IC19 Plenary and
Keynote Abstracts
Wollongong, Australia
15th‐19th December
2019
1
Inorganic 19 Plenary Speakers
Sir Fraser Stoddart (University of New South Wales)
Sir Fraser has wide‐ranging research interests. Most well‐
known for his research on mechanically interlocked
molecules and molecular machines, leading to the award of
a Nobel prize, he has made contributions to the area of
porous crystalline polymers and will talk about metal‐
organic frameworks made from cyclodextrins.
Professor Christine McKenzie (University of Southern
Denmark)
Christine's interests centre on coordination and bioinorganic
chemistry. In particular, small molecule activation and gaining
spin‐state control over first row transition metal complexes so
they can selectively activate terminal oxidants for
implementation in range of catalytic C‐H oxidations. I will talk
about molecular iron chemistry, terminal oxidant activation and
catalysis.
Professor Hai‐Bo Yang (ECNU Shanghai)
Dr. Yang's research interests span the areas of organic,
organometallic, and supramolecular chemistry. In particular, he is
very interested in supramolecular coordination complexes (SCCs)
and their applications in materials science. His presentation will
concern the construction of stimuli‐responsive functional materials
through hierarchical self‐assembly involving coordination bonds.
2
Professor Eva Hevia (University of Bern)
Eva's research focuses on polar organometallic chemistry at the
crossroads of inorganic, organic, and green chemistry. Some of her
recent contributions include the use of cooperative bimetallic
compounds for the activation of pharmaceutically relevant organic
molecules, as well as the advancement of new methods that
replace the use of toxic organic solvents in this chemistry by more
sustainable and biorenewable systems.
Professor Hongzhe Sun (University of Hong Kong)
Hongzhe’s research lies in the chemical biology of metals,
particularly metals in biology and medicine. He is a pioneer in
bioinorganic metalloproteomics chemistry and recognized for his
work at the cutting edge between inorganic chemistry and
biology/medicine to uncover potential metallodrug binding
proteins in pathogens, metallobiology, and overcoming
antimicrobial resistance.
Professor Michaele Hardie (University of Leeds)
Research interests are in the areas of metallosupramolecular
chemistry, new molecular hosts and chemical crystallography, with
particular interests in the self‐assembly of discrete nano‐scale
(metallo)supramolecular cages using host‐type ligand scaffolds,
functional multi‐nuclear complexes, and coordination polymers
and metal‐organic frameworks.
3
Inorganic19 Keynote Speakers
Dr Gilles Gasser (Chimie ParisTech)
Research in the Gasser group lies at the interface between
inorganic chemistry, medicinal chemistry, chemical biology and
biology and concerns the utilisation of metal complexes for
biological and medicinal purposes. He will present the latest
results of his group on the use of metal‐based compounds in
medicine.
Associate Professor Colette Boskovic (University of Melbourne)
Research in the Boskovic Group is focused on inorganic molecular
materials relevant to the fields of molecular magnetism,
lanthanoid chemistry, redox‐active ligands and switchable
molecules. In her talk at IC19, Colette will present recent research
results concerning switchable molecular materials with redox‐
active ligands.
Professor Martyn Coles (Victoria University of Wellington)
Research in the Coles group is focussed on the chemistry of main
group elements in low oxidation‐states with recent emphasis on
antimony and bismuth complexes in 1+ or 2+ oxidation‐states. He
will present his recent results on the synthesis and reactivity of low
oxidation‐state aluminyl and indyl anions.
Associate Professor Pheobe Glazer (University of Kentucky)
Research in the Glazer group seeks to understand dynamic
biological and chemical processes utilising photoactive metal
complexes as probes and photoswitchable molecules for pro‐
drugs. A range of biochemical techniques, and biophysics
approaches, are used to interrogate biomolecules. Our recent
results will be presented at IC19.
4
Professor Mark MacLachlan (University of British Columbia)
Mark's research interests range from macrocyclic and coordination
chemistry to new materials based on cellulose nanocrystals where
he has developed a new family of templated mesoporous inorganic
materials with photonic properties.
Professor Penelope Brothers (Australian National University)
Current research interests centre around the intriguing chemistry
of boron coordinated to porphyrin and corrole ligands, metallated
BODIPY fluorophores for sugar recognition and photocatalytic
hydrogen production and supramolecular surface patterning using
molecular pentagons. The latest results from our research will be
presented at IC19.
Professor Shane Telfer (Massey University)
Shane is a synthetic chemist at heart, with a particular interest in
things inorganic and chiral. Lately, this has extended to porous and
catalytically‐active materials. I will present a talk on gas
separations using some straightforward and robust metal‐organic
frameworks and relay how we can understand the performance of
these materials using X‐ray crystallography.
Dr Rebecca Melen (Cardiff University)
Main Group chemistry has undergone a renaissance in recent years
with the realisation that the reactivity of main group elements
often closely resembles that of transition metals in small molecule
activation and catalysis. Research in the Melen group focuses on
main group catalyst design as well as the applications of main
group Lewis acids in organic synthesis and catalytic processes. Dr
Melen's talk will discuss recent developments in the Melen group
that investigate new directions in metal free catalysis to provide
new openings in both the synthesis and applications of main group
compounds.
5
Monday 16 December 2019
Room 67‐107 Page
09:00‐10:00 Plenary 1 A Janus‐faced iron catalyst
Professor Christine McKenzie (University of Southern Denmark) Chair: Stephen Ralph
9
14:00‐15:00 Plenary 2 Stimuli‐responsive functional materials via hierarchical self‐assembly involving coordination interactions
Professor Haibo Yang (East China Normal University) Chair: Nicholas White
10
Tuesday 17 December 2019
Room 67‐107
09:00‐10:00 Plenary 3 Towards a paradigm shift in main group polar organometallic chemistry
Professor Eva Hevia (University of Bern) Chair: Victoria Blair
11
14:00‐15:00 Plenary 4 From metalloproteomics to drug development: bismuth‐based agents as inhibitors against metallo‐β‐lactamase
Professor Hongzhe Sun (The University of Hong Kong) Chair: Professor Janice Aldrich‐Wright
12
Wednesday 18th December 2019
Room 67‐107
09:00‐10:00 Plenary 5 Taking cyclodextrin metal‐organic frameworks from the research laboratory to the market place
Professor Fraser Stoddart (Northwestern University) Chair: Jonathan Beves
13
Thursday 19 December 2019
Room 67‐107
09:00‐10:00 Plenary 6 Coordination cages and other assemblies from pyramidal ligands: self‐sorting, shape‐changing, guest binding and more
Professor Michaele Hardie (University of Leeds) Chair: Chris Richardson
14
16:00‐17:00 Burrows Award lecture Understanding metal‐catalysed reactions using electrochemistry
Professor Paul Bernhardt (University of Queensland) Chair: Louis Rendina
15
6
Monday 16 December 2019
Room 67‐107 Page
10:00‐10:30 Keynote 1 Switchable cobalt complexes with redox‐active ligands A/Prof Colette Boskovic (University of Melbourne)
Chair: Stephen Ralph
17
13:30‐14:00 Keynote 2 Adventures with metal‐containing macrocycles
Professor Mark MacLachlan (University of British Columbia) Chair: Nicholas White
18
Tuesday 17 December 2019
Room 67‐107
10:00‐10:30 Keynote 3 Synthesis and reactivity of indyl‐anions
Professor Martyn Coles (Victoria University of Wellington) Chair: Victoria Blair
19
13:30‐14:00 Keynote 4 Controlling coordinative bonds in metallodrugs and metallotargets for medical applications
Professor Phoebe Glazer (University of Kentucky) Chair: Professor Janice Aldrich‐Wright
20
Wednesday 18th December 2019
Room 67‐107
10:00‐10:30 Keynote 5 Gas separations using sustainable and robust metal‐organic frameworks
Professor Shane Telfer (Massey University) Chair: Jonathan Beves
21
Thursday 19 December 2019
Room 67‐107
10:00‐10:30 Keynote 6 Metal complexes in medicinal chemistry Dr Gilles Gasser (Chemie ParisTech)
Chair: Chris Richardson
22
13:30‐14:00 Keynote 7 Lewis acidic boranes in synthesis and catalysis
Dr Rebecca Melen (Cardiff University) Chair: Annie Colebatch
23
15:30‐16:00 Keynote 8 Fluorescent sugars and other applications of boron pyrrole complexes
Professor Penelope Brothers (Australian National University) Chair: Louis Rendina
24
7
Plenary Abstracts
8
A JANUS-FACED IRON CATALYST
Christine J. McKenzie1
1Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark.
E-mail: [email protected]
Clean catalysis of oxidation reactions remains a challenge for chemists. Through coordinative flexibility, an
ostensibly coordinatively saturated iron(III) complex can catalyse substrate C-H oxidation by H-atom
abstraction, or, at the other end of the reactivity scale, selective oxygenation. These mechanistic extremes
open-up for new methodologies for doing greener catalytic oxidation reactions in fields as divergent as water
remediation and fine chemicals synthesis.
Catalytic oxidations using peroxides[1] as the terminal chemical oxidant can be performed in water, however
intriguingly electrocatalysis[2] - where water is part of the atom balance - can be applied in place of a terminal
chemical oxidant. A spectroscopically detected Fe(IV)oxo species is the catalytically competent oxidant. We
are currently investigating this technique for its potential as an electrocatalytic method for the total
mineralization of trace organic pollutants like pesticides in water. In non-protic solvents, the practical, but
highly insoluble polymeric oxidant, “hypervalent” iodosylbenzene [PhIO]n is readily mobilized.[3,4] Here a
detected Fe-OIPh adduct, or an undetected Fe(V)oxo derivative, transfers an O atom to substrates.
The time-resolved spectroscopic characterisation of the various intermediates will be described along with the
rationalisation behind the mechanisms proposed. In the absence of water, or chemical oxidants, sunlight
triggers the decarboxylation of the resting state complex and an ensuing O2-dependent oxidation of the
ligand.[5]
[1] C. Wegeberg, W. R. Browne, C. J. McKenzie. ACS Catalysis, 2018, 8, 9980; C. Wegeberg, F. R.
Lauritsen, C. Frandsen, S. Mørup, W. R. Browne, C. J. McKenzie, Chem., A Eur. J. 2018, 24, 5134.
[2] D. P. de Sousa, C. J. Miller, Y. Chang, T. D. Waite, C. J. McKenzie, Inorg. Chem., 2017, 56, 14936.
[3] C. Wegeberg, C. G. Frankær and C. J. McKenzie, Dalton Trans, 2016, 45, 17714.
[4] D. P. de Sousa, C. Wegeberg, M. V. Sørensen, S. Mørup, C. Frandsen, W. A. Donald and C. J. McKenzie,
Chem, Eur. J. 2016, 22, 3521; A. Lennartson and C. J. McKenzie, Angew. Chem., Int. Ed., 2012, 51, 6767.
[5] C. Wegeberg, V. M. Fernández-Alvarez, A. de Aguirre, C. Frandsen, W. R. Browne, F. Maseras, C. J.
McKenzie, J. Am. Chem. Soc., 2018, 140, 14150.
9
STIMULI-RESPONSIVE FUNCTIONAL MATERIALS VIA HIERARCHICAL SELF-ASSEMBLY INVOLVING
COORDINATION INTERACTIONS
Hai-Bo Yang*
East China Normal University, Shanghai, 200062, China Email: [email protected]
Figure 1. Hierarchical self-assembly involving coordination interactions
Hierarchical self-assembly is omnipresent in many biological systems and has been widely explored in
construction of artificial functional supramolecular systems. Based on our previous research on coordination-
driven self-assembly of functional metallacycles[1], recently, we have expanded our research towards the
construction of stimuli-responsive functional materials via hierarchical self-assembly involving coordination
interactions[2]. The judicious combination of reversible coordination in metallacycles with other non-covalent
interactions allows for the fabrication of a variety of stimuli-responsive nanostructures and functional
materials. For example, various nanostructures, supramolecular metallohydrogels, stimuli-responsive
supramolecular polymers, and vapochromic materails have been successfully prepared by this strategy with
the tailored chemical and physical properties[3]. In addtion, the first example of the rotaxane-branched
dendrimers with high generation was successfully realized by using the similar strategy[4].
References:
[1] (a) L. Xu, Y.-X. Wang, L.-J. Chen, H.-B. Yang*. Chem. Soc. Rev. 2015, 44, 2148; (b) W. Wang, Y.-X. Wang, H.-B.
Yang,* Chem. Soc. Rev. 2016, 45, 2656; (c) L.-J. Chen, H.-B. Yang,* M. Shionoya*. Chem. Soc. Rev. 2017, 46, 2555.
[2] L.-J.Chen, H.-B. Yang*. Acc. Chem. Res., 2018, 51, 2699.
[3] (a) Z.-Y. Li, Y. Zhang, C.-W. Zhang, L.-J. Chen, C. Wang, H. Tan, Y. Yu, X. Li, H.-B. Yang*. J. Am. Chem. Soc.
2014, 136, 8577 (Page Cover); (b) B. Jiang, J. Zhang, J.-Q. Ma, W. Zheng, L.-J. Chen, B. Sun, C. Li, B.-W. Hu, H.
Tan, X. Li, H.-B. Yang*. J. Am. Chem. Soc. 2016, 138, 738; (c) W. Zheng, G. Yang, N. Shao, L.-J. Chen, B. Ou, S.-T.
Jiang, G. Chen,* H.-B. Yang*. J. Am. Chem. Soc. 2017, 139, 13811; (d) W. Zheng, L.-J. Chen, G. Yang, B. Sun, X.
Wang, B. Jiang, G.-Q. Yin, L. Zhang, X. Li, M. Liu, G. Chen,* H.-B. Yang*. J. Am. Chem. Soc. 2016, 138, 4927; (e)
G.-Q. Yin, H. Wang, X.-Q. Wang, B. Song, L.-J. Chen, L. Wang, X.-Q. Hao, H.-B. Yang,* X. Li*. Nat. Commun.
2018, 9, 567.
[4] (a) W. Wang, L.-J. Chen, X.-Q. Wang, B. Sun, X. Li, Y. Zhang, J. Shi, Y. Yu, L. Zhang, M. Liu, H.-B. Yang*. PNAS,
2015, 112, 5597; (b) X.-Q. Wang, W. Wang, W.-J. Li, L.-J. Chen, R. Yao, G.-Q. Yin, Y.-X. Wang, Y. Zhang, J.
Huang, H. Tan, Y. Yu, X. Li, L. Xu,* H.-B. Yang*. Nat. Commun. 2018, 9, 3190.
10
TOWARDS A PARADIGM SHIFT IN MAIN GROUP POLAR ORGANOMETALLIC CHEMISTRY
Eva Hevia* Department of Chemistry and Biochemisty, University of Bern, Switzerland
Email: [email protected] Organolithium compounds (e.g., alkyls, aryls and amides) have been and remain pivotal to the development of synthetic chemistry. Staple reagents in academic laboratories and chemical industries worldwide, their extensive utilization reflects their high reactivity and selectivity (notably in directed ortho-metallation and metal-halogen exchange). However, in many cases this high reactivity can also compromise their functional group tolerance, imposing the use of severely restrictive protocols (e.g., moisture- and oxygen-free organic solvents, inert atmospheres, extremely low temperatures etc.) and frequently the lithiated organic intermediates can be unstable and decompose. This presentation will explore alternative organometallic strategies to overcome some of these major drawbacks faced by standard organolithium reagents. This includes the use of bimetallic combinations for deprotonative metallation and metal halogen exchange reactions, which enable the trapping of sensitive anions while operating at room temperature (see Scheme).1 Furthermore, the promising use of non-conventional solvent systems such as Deep Eutectic Solvents (DES) in organolithium chemistry will also be discussed,2 edging closer towards developing greener and air and moisture compatible methodologies. References 1. (a) R. McLellan, M. Uzelac, A. R. Kennedy, E. Hevia, R. E. Mulvey, Angew. Chem. Int. Ed. 2017, 56,
9566. (b) L. C. H. Maddock, T. Nixon, A. R. Kennedy, M. R. Probert, W. Clegg and E. Hevia, Angew. Chem. Int. Ed. 2018, 57, 187. (c) M. Balkenhohl, D. S. Ziegler, A. Desaintjean, L. J. Bole, A. R. Kennedy, E. Hevia, P. Knochel, Angew. Chem. Int. Ed. 2019, early view.
2. (a) C. Vidal, J. Garcia-Alvarez, A. Hernan-Gomez, A. R. Kennedy, E. Hevia, Angew. Chem. Int. Ed. 2016, 55, 16145. (c) M. J. Rodriguez-Alvarez, J. Garcia-Alvarez, M. Uzelac, M. Fairley, C. T. O’Hara, E. Hevia, Chem. Eur. J. 2018, 24, 1720. (d) A. Sanchez-Condado, G. A. Carriedo, A. Presa-Soto, M. J. Rodriguez-Alvarez, J. Garcia-Alvarez, E. Hevia, ChemSusChem, 2019, 12, 334.
OMe
I 2 LiOtBu. ZnsBu2
rt, 30min, THF- 2 sBuI
OMe
Zn.2LiOtBu2
F
H
Direct Zn-Halogen exchage1c
Sodium mediated ferration1b
dioxane, 80oC, 10h
F
Fe
NNa
N
N = N(SiMe3)2
[NaFe{N(SiMe3)2}3]
11
FROM METALLOPROTEOMICS TO DRUG DEVELOPMENT: BISMUTH-BASED AGENTS AS INHIBITORS AGAINST
METALLO--LACTAMASE
Hongzhe Sun,1* Runming Wang1,2, Pak-Leung Ho2, Richard Yi-Tsun Kao2, Hongyan Li1
1Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, P.R. China 2Department of Microbiology, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, P.R. China
Email: [email protected]
Metal compounds have long been used in medicine and healthcare. Metal- and metallodrug-protein
interactions play a crucial role for transition metals and the action of metallodrugs. It is important to identify
metal-protein interactions at a proteome-wide scale, which is difficult due to the diversity of metal-protein
interactions.1,2 We developed an integrated approach to identify metal-associated proteins using bismuth,
silver and gallium as an example3 as well as to quantify the metals for rapid metallome/proteome-wide
profiling of metal-binding proteins.
Based on our integrative metallomic approach, we have found that Bi(III) interferes with Zn(II) biochemistry
in pathogens and propose to use Bi(III) compounds to inhibit metallo-β-lactamases (MBLs). Infections caused
by metallo-β-lactamases (MBLs), e.g., New Delhi metallo-β-lactamase 1(NDM-1) producing bacteria are
extremely difficult to treat.4 We show that an anti-ulcer agent, colloidal bismuth subcitrate (CBS), and related
Bi(III) compounds irreversibly inhibit different types of MBLs. CBS restores meropenem (MER) efficacy
against MBL-positive bacteria in vitro, and in animal infection models.5 Surprisingly, one Bi(III) replaces two
Zn(II)ions in the active site, and Bi(III) drugs can slow down the development of resistance. We demonstrate
the high potential of Bi(III) compounds as the first broad-spectrum MBL inhibitors to treat MBL producing
bacterial infection in combined use with existing carbapenems. Our approach has been successfully extended
to Ga(III) and Ag(I), opening a new horizon for metals in biology and toxicology.
We thank the Research Grants Council of Hong Kong (R7070-18) and the University of Hong Kong (URC and
Norman and Cecilia Yip Foundation) for support.
[1] K. J. Waldron, J. C. Rutherford, D. Ford, N. J. Robinson, Nature 2009, 460, 823-830.
[2] X. S. Sun, C.N. Tsang, H. Sun, Metallomics 2009, 1, 25-31.
[3] Y. C. Wang, B.J. Han, Y. X. Xie, H.B. Wang, R .M. Wang, X. Xia, H. Li, H. Sun, Chem Sci 2019, 10,
6099-6016.
[4] A. M. King, S. A. Reid-Yu, G. D. Wright, et al, Nature 2014, 510, 503-506.
[5] R. M. Wang, T. P. Lai, P. L. Ho, P. C. Woo, R. Y. Kao, H. Li, H. Sun et al, Nat Commun 2018, 9, 439.
12
TAKING CYCLODEXTRIN METAL-ORGANIC FRAMEWORKS FROM THE RESEARCH LABORATORY TO THE
MARKET PLACE
J. Fraser Stoddart1*
1 Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA Email: [email protected]
Porous metal–organic frameworks (MOFs) have been studied in the context of a wide variety of applications, particularly in relation to molecular storage and separation sciences. In 2010, we reported a green, renewable framework material composed of γ-cyclodextrin (γ-CD) and alkali metal salts—namely, CD-MOF.1 These cubic CD-MOFs are (i) stable to the removal of solvents, (ii) permanently porous, with surface areas of ∼1200 m2g–1, and (iii) capable of storing gases and small molecules within their pores.2 They have been shown to facilitate the separation of mixtures of alkyl/aromatic compounds, including the BTEX mixture (benzene, toluene, ethylbenzene, and the regioisomers of xylene), into their pure components, in both the liquid and gas phases, in an energy-efficient manner which could have implications for the petrochemical industry.3 In particular, CD-MOF has the ability to separate a wide variety of mixtures, including ethylbenzene from styrene, haloaromatics, terpinenes, pinenes and other chiral compounds.4 Since CD-MOF is a homochiral framework, it is also able to resolve the enantiomers of chiral analytes, including those of limonene and 1-phenylethanol. In 2017, we incorporated ibuprofen within CD-MOF-1 either by (i) a crystallization process using the potassium salt of ibuprofen as the alkali cation source for production of the MOF or by (ii) absorption and deprotonation of the free-acid, leading to an uptake of 23–26 wt% of ibuprofen within the CD-MOF.5 These inexpensive, green, nanoporous materials exhibit absorption properties which make them realistic candidates for commercial development, not least of all because edible derivatives, fit for human consumption, can be prepared entirely from food-grade ingredients. In this lecture, the story of CD-MOFs will be presented, as we venture from the lab to the market place. [1] R. A. Smaldone, R. S. Forgan, H. Furukawa, J. J. Gassensmith, A. M. Z. Slawin, O. M. Yaghi and J. F. Stoddart, Angew. Chemie Int. Ed. 2010, 49, 8630. [2] D. Wu, J. J. Gassensmith, D. Gouvêa, S. Ushakov, J. F. Stoddart and A. Navrotsky, J. Am. Chem. Soc. 2013, 135, 6790. [3] J. M Holcroft, K. J. Hartlieb, P. Z. Moghadam, J. G. Bell, G. Barin, D. P. Ferris, E. D. Bloch, M. M. Algaradah, M. S. Nassar, Y. Y. Botros, K. M. Thomas, J. R. Long, R. Q. Snurr and J. F. Stoddart, J. Am. Chem. Soc. 2015, 137, 5706. [4] K. J. Hartlieb, J. M. Holcroft, P. Z. Moghadam, N. A. Vermeulen, M. M. Algaradah, M. S. Nassar, Y. Y. Botros, R. Q. Snurr and J. F. Stoddart, J. Am. Chem. Soc. 2016, 138, 2292. [5] K. J. Hartlieb, D. P. Ferris, J. M. Holcroft, I. Kandela, C. L. Stern, M. S. Nassar, Y. Y. Botros and J. F. Stoddart, Mol. Pharmaceutics 2017, 14, 1831.
13
COORDINATION CAGES AND OTHER ASSEMBLIES FROM PYRAMIDAL LIGANDS: SELF-SORTING, SHAPE-CHANGING, GUEST-BINDING AND MORE
Edward Britton1, James Henkelis1, Samuel Oldknow1, Victoria Pritchard1, Diego Rota Martir2, FloraThorp-Greenwood1, Eli Zysman-Colman2 and Michaele J. Hardie1*
1School of Chemistry, University of Leeds, Leeds LS2 9 JT, UK2EaStCHEM School of Chemistry, University of St Andrews, St Andrews KY16 9ST, UK
Email: [email protected]
Cyclotriveratrylene (= CTV) is a pyramidal host molecule. We have developed a range of chiral tripodal CTV-analogues (L-type ligands) where the CTV scaffold has been functionalized with metal-binding ligand groups,and form discrete metallated cavitands, coordination cages, coordination polymers and other networkedassemblies. These include unusual topologically complicated assemblies including a self-knotted cube [1] and aunique chain-mail of Borromean rings.[2] A family of [Pd6L8] stella octangula cages can be synthesised, wheresmall variations to the L ligand leads to different solution self-assembly and chiral self-sorting behaviour andstabilities. These differences can be exploited to dynamically control mixed ligand Pd6L8 speciation insolution.[3] The smallest class of cages are M3L2 capsule assemblies analogous to organic cryptophanes. M3L2
metallo-cryptophanes can be formed from a variety of metal and ligand combinations and frequently form asdimeric interlocked cage-catenane assemblies. Formation of M3L2 cages often requires a protecting chelatingligand on the metal which can be organometallic in nature. For example, [Pd3(bis-NHC)3L2] cages (pictured)where bis-NHC is a chelating N-heterocyclic carbene ligand form crystalline materials that bind I2,[4] and[{Ir(ppy)2}3L2]3+ metallocryptophanes, where ppy is 2-phenylpyridine are luminescent.[5] We have recentlydeveloped a series of [{Ir(C^N)2}3L2]3+ cages with embedded photo-switchable azo-groups. These show photo-induced trans-to-cis structure switching, the first examples of such switching of a structurally integral azo-unitwithin a metallo-cage (pictured).[6]
[1] T. K. Ronson, J. Fisher, L.P. Harding, P. J. Rizkallah, J. E. Warren,. M. J. Hardie, Nature Chem. 2009, 1,212.[2] F. L. Thorp-Greenwood, A. N. Kulak, M. J. Hardie, Nature Chem. 2015, 7, 526.[3] J. J. Henkelis, J. Fisher, S. L. Warriner, M. J. Hardie, Chem. Eur. J. 2014, 20, 4117.[4] J. J. Henkelis, C. J. Carruthers, S. E. Chambers, R. Clowes, A. I. Cooper, J. Fisher, M. J. Hardie, J. Am.Chem. Soc. 2014, 136, 14393.[5] V. E. Pritchard, D. Rota Martir, S. Oldknow, S. Kai, S. Hiraoka, N. J. Cookson, E. Zysman-Colman, M. J.Hardie, Chem. Eur. J. 2017, 23, 6290.[6] S. Oldknow, D. Rota Martir, V. E. Pritchard, M. A. Blitz, C. W. G. Fishwick, E. Zysman-Colman, M. J.Hardie, Chem. Sci. 2018, 9, 8150.
14
UNDERSTANDING METAL-CATALYSED REACTIONS USING ELECTROCHEMISTRY Paul V. Bernhardt
School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072 Email: [email protected]
Transition elements are unique in their ability to stabilise multiple oxidation states, which is facilitated by their flexible d-electron configurations. Reversible electron transfer reactions of transition metals are central to the function of both synthetic and biological catalytic processes where electron transfer is coupled to atom transfer involving a substrate/ligand to achieve a redox reaction that otherwise is kinetically unfavourable. We have used electrochemical methods such as cyclic voltammetry to investigate the mechanisms of both synthetic and biological redox catalysis. Under suitable conditions the rates of individual steps of the reaction mechanism may be extracted to provide information that is not measurable by any other method.
Mred Mox
e-
S P
electrode
Our investigations have provided new insight into synthetic catalysts employed in polymer chemistry[1,2] and organic synthesis.[3] Similar approaches have been taken to interrogate the active sites of metalloenzymes, most notably the mononuclear molybdenum enzyme family[4,5] where we have investigated a range of enzymes using direct and mediated electrochemical methods. Our research has revealed some unusual reactive intermediates and unanticipated side products. References [1] C. A. Bell, P. V. Bernhardt, M. J. Monteiro, J. Am. Chem. Soc. 2011, 133, 11944–11947. [2] T. J. Zerk, L. R. Gahan, E. H. Krenske, P. V. Bernhardt, Polym. Chem. 2019, 10, 1460-
1470. [3] T. J. Zerk, P. W. Moore, C. M. Williams, P. V. Bernhardt, Chem. Commun. 2016, 52, 10301-
10304. [4] P. Kalimuthu, P. V. Bernhardt, in Molybdenum and Tungsten Enzymes: Spectroscopic and
Theoretical Investigations (Eds.: R. Hille, C. Schulzke, M. L. Kirk), Royal Society of Chemistry, Cambridge, UK, 2017, pp. 168-222.
[5] P. V. Bernhardt, Chem. Commun. 2011, 47, 1663-1673.
15
Keynote Abstracts
16
SWITCHABLE COBALT COMPLEXES WITH REDOX-ACTIVE LIGANDS
Gemma K. Gransbury1, Tina Tezgerevska,1 Brooke N. Livesay,2 Matthew P. Shores,2 Alyona A. Starikova3 and Colette Boskovic1*
1School of Chemistry, University of Melbourne, VIC, Australia 2 Department of Chemistry, Colorado State University, USA
3 Institute of Physical & Organic Chemistry, Southern Federal University, Russian Federation Email: [email protected]
Molecular materials that can be switched between different forms by application of an external stimulus are of interest for future applications in display devices, high-density data storage and molecular spintronics. Important examples include spin crossover (SCO) complexes that can be interconverted between low and high spin states of the metal centre and valence tautomeric (VT) complexes, which undergo a stimulated intramolecular electron transfer between the metal and a redox-active ligand.1,2 For cobalt-dioxolene systems, the most common type of VT complexes, a spin transition at the cobalt accompanies the electron transfer. Our recent work in this field has focussed on exploring families of cobalt-dioxolene complexes, for which different members exhibit either SCO or VT transitions.3,4 We have employed density functional theory to predict whether analogues will undergo SCO or VT transitions, which we have verified experimentally.5 In tandem, we have developed a generally applicable electrochemistry-based approach to assess whether a VT interconversion is likely to be observed. We have extended this approach to dinuclear systems and have elucidated the role of intramolecular electronic communication in engendering two-step VT transitions.6 This understanding has allowed us to establish design guidelines for dinuclear complexes that can be switched between three distinguishable electronic states. References 1 H. A. Goodwin. Top. Curr. Chem. 2004, 234, 23. 2 T. Tezgerevska, K. G. Alley, C. Boskovic, Coord. Chem. Rev. 2014, 268, 23. 3 M. Graf, G. Wolmershäuser, H. Kelm, S. Demeschko, F. Meyer, H.-J. Krüger. Angew. Chem. Int. Ed.
Engl. 2010, 49, 950. 4 T. Tezgerevska, E. Rousset, R. W. Gable, G. N. L. Jameson, E. C. Sañudo, A. A. Starikova, C. Boskovic.
Dalton Trans. 2019, doi: 10.1039/C9DT02372K. 5 G. K. Gransbury, M. E. Boulon, S. Petrie, R. W. Gable, R. J. Mulder, L. Sorace, R. Stranger, C.
Boskovic. Inorg. Chem. 2019, 58, 4230. 6 G. K. Gransbury, B. N. Livesay, R. W. Gable, M. P. Shores, A. A. Starikova, C. Boskovic, "Valence
Tautomerism in Dinuclear Cobalt Complexes Bridged by a Brominated Spiro Ligand", manuscript in preparation.
17
ADVENTURES WITH METAL-CONTAINING MACROCYCLES
Mark J. MacLachlan1*, Mohammad T. Chaudhry1 and Zhengyu Chen1
1Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1 Canada Email: [email protected]
Figure 1. (a) Chemical structure of Pt-containing macrocycle without substituents. (b) Structure of Pt-
containing macrocycle shows a rigid, porous structure. (c) Chemical structure of a campestarene macrocycle.
(d) Structure of campestarene macrocycle shows strong intramolecular hydrogen bonding and a nearly-planar
macrocycle.
Macrocycles have been central to the development of supramolecular chemistry and offer unique, tunable
environments for coordination chemistry.1 The condensation of aldehydes and amines can create novel
compounds with Schiff bases, ranging from macrocycles2 to Borromean rings.3 Although the reversibility of
this reaction is often a menace in preparative chemistry of imine-containing molecules, it enables the isolation
of thermodynamically stable complex products. We have been exploring the synthesis, self-assembly, and
coordination chemistry of Schiff base macrocycles for many years. In this talk, I will present some of our
group’s research on the synthesis and properties of new macrocycles, such as platinum-containing pyridyl-
containing macrocycles4,5 and campestarenes and their emerging coordination chemistry.6-8 Figure 1 shows the
structures of the rigid Pt-containing macrocycles and campestarenes that we have been investigating.
1 L. F. Lindoy, The Chemistry of Macrocyclic Ligand Complexes, Cambridge University Press: Cambridge,
1989. 2 N. E. Borisova, M. D. Reshetova, Y. A. Ustynyuk. Chem. Rev. 2007, 107, 46. 3 K. S. Chichak, S. J. Cantrill, A. R. Pease, S.-H. Chiu, G. W. V. Cave, J. F. Stoddart. Science 2004, 304, 1308. 4 P. D. Frischmann, S. Guieu, R. Tabeshi, M. J. MacLachlan. J. Am. Chem. Soc. 2010, 132, 3893. 5 Z. Chen, B. J. Sahli, M. J. MacLachlan. Inorg. Chem. 2017, 56, 5383. 6 S. Guieu, A. K. Crane, M. J. MacLachlan. Chem. Commun. 2011, 47, 1169. 7 Z. Chen, S. Guieu, N. G. White, F. Lelj, M. J. MacLachlan. Chem. Eur. J. 2016, 22, 17657. 8 M. T. Chaudhry, F. Lelj, M. J. MacLachlan. Chem. Commun. 2018, 54, 11869.
18
SYNTHESIS AND REACTIVITY OF INDYL-ANIONS
Mathew D. Anker,1 Ryan J. Schwamm and Martyn P. Coles*
1School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand Email: [email protected]
Recent developments in the chemistry of low-valent indyl-anions A, supported by chelating bis(amidodimethyl)disiloxane ligands will be presented.[1] The In(I) centre in A reduces organic azides RN3 to afford indium-imides, that behave chemically as In=NR multiple bonds.[2] The nucleophilic properties of A have also been demonstrated through the formation of complexes containing In–M' bonds (M' = Zn, Cd). The reactivity of these bimetallic compounds displays behaviour that is reminiscent of either (i) early-late heterobimetallic (ELHB) compounds of the transition elements, or (ii) highly reducing homobimetallic compounds of Mg(I) or Zn(I). The factors that determine which pathway dominates the reactivity profile has been explored. References [1] R. J. Schwamm, M. D. Anker, M. Lein, M. P. Coles, C. M. Fitchett, Angew. Chem. Int. Ed. 2018, 57,
5885-5887. [2] M. D. Anker, M. Lein, M. P. Coles, Chem. Sci. 2019, 10, 1212-1218.
19
CONTROLLING COORDINATIVE BONDS IN METALLODRUGS AND METALLOTARGETS FOR MEDICAL
APPLICATIONS
Edith (Phoebe) Glazer1
1 Department of Chemistry, University of Kentucky, Lexington, Kentucky, United States Email: [email protected]
Metal-containing systems exhibit highly variable chemistries, and greatly expand the repertoire of chemical interactions and reactions that can be achieved utilizing compounds with standard covalent bonds. This enhanced chemistry is a result of the unique and often plastic features of coordinative bonds, which have allowed both nature and chemists to create molecules and materials with a wide range of properties, ranging from enzymes to essential industrial catalysts to drugs. Our goal is to develop an integrated platform for drug discovery centered around 1) inorganic compounds containing exchangeable coordinative bonds to ligands, and 2) drug-inspired ligands that form coordinative bonds to metal-containing biomolecules. Our approach to the first research topic is the development of ruthenium complexes that can be triggered by specific stimuli to release ligands to subsequently form new covalent bonds to biomolecules or to deliver biologically active ligands in a spatially and temporally controlled fashion. The second component of the platform involves targeting Cytochrome P450 (CYP) metalloproteins, which can be inactivated by coordinating ligands that have been developed for both active site- and metal-center complementarities. Using a building block approach for both projects, we are able to rapidly generate chemical diversity from synthetically accessible starting materials. However, the very versatility of inorganic systems is a double-edged sword, as our understanding of the structural and electronic features in metal complexes that are the cause that results in a specific photophysical, photochemical, or biological effect has lagged behind our ability to design and test novel systems. Structural and spectroscopic studies will be presented that are yielding new insights as we attempt to define the “rules” of photochemical transformations of ruthenium compounds. In a complementary approach, we are working towards an understanding of P450 structural flexibility and dynamics that can be exploited for the development of drugs selective for specific P450 enzymes that play a role in cancer initiation, progression, and resistance to treatment.
20
GAS SEPARATIONS USING SUSTAINABLE AND ROBUST METAL-ORGANIC FRAMEWORKS Shane Telfer
MacDiarmid Institute for Advanced Materials and Nanotechnology, Massey University, Palmerston North, New Zealand
Email: [email protected]
Metal-organic frameworks (MOFs) are porous crystalline materials that can often sequester molecular guests.
MOFs are distinguished from other porous materials by their diversity and structural regularity. Bottom-up self-
assembly of these frameworks allows for control over the shape, size and chemical characteristics of their pore
spaces. While many MOFs are too expensive or sensitive to consider for bulk separations, robust high-
performance materials can be prepared using readily-available components. Advances in this area are likely to
underpin sustainable solutions to real-world challenges.
I will report on our recent research on molecular separations using a series of robust MOFs using inexpensive
precursors. The spatial environment in these materials can be precisely tailored to the selective capture of
particular guest molecules. Owing to these characteristics, these materials can effect the separation of very
similar gases and remove low-level impurities. I will highlight our recent work on the capture of carbon dioxide
and the separation of ethane, ethylene, and acetylene.[1]
[1] O. T. Qazvini, R. Babarao, Z. L. Shi, Y. B. Zhang, and S. G. Telfer, J. Am. Chem. Soc. 2019, 141, 5014.
21
LEWIS ACIDIC BORANES IN SYNTHESIS AND CATALYSIS
Rebecca L. Melen1*
1 School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK
Email: [email protected]
As main group chemistry, in particular boron chemistry, has expanded and developed over the past 20 years,
one reagent has risen to prominence as well. Tris(pentafluorophenyl)borane, B(C6F5)3, (commonly known as
BCF) has demonstrated extensive applications in a wide variety of chemistry, including borylations,
hydrogenations, hydrosilylations, frustrated Lewis pair chemistry, Lewis acid catalysis and more.1 The high
Lewis acidity of B(C6F5)3 is achieved from the electronic effects of its three C6F5 rings, rendering it a versatile
reagent for a great number of reactions. The talk will show our recent uses of Lewis acidic boranes in organic
synthesis and catalysis (Figure 1) and will also focus on our latest advances in novel borane and borocation
usage.2-5
Figure 1
1. G. Erker, Dalton Trans., 2005, 1883; G. C. Welch, R. R. San Juan, J. D. Masuda, D. W. Stephan, Science,
2006, 314, 1124; R. L. Melen, Chem. Commun., 2014, 50, 1161.
2. L. C. Wilkins, B. A. R. Günther, M. Walther, J. R. Lawson, T. Wirth, R. L. Melen, Angew. Chem. Int. Ed.,
2016, 55, 11292.
3. I. Khan, B. G. Reed-Berendt, R. L. Melen, L. C. Morrill, Angew. Chem. Int. Ed., 2018, 57, 12356.
4. I. Khan, M. Manzotti, G. J. Tizzard, S. J. Coles, R. L. Melen, L. C. Morrill, ACS Catalysis, 2017, 7, 7748.
5. M. Santi, D. M. C. Ould, J. Wenz, Y. Soltani, R. L. Melen, T. Wirth, Angew. Chem. Int. Ed., 2019, 58, 7861.
22
METAL COMPLEXES IN MEDICINAL CHEMISTRY
Gilles Gasser1*
1Chimie ParisTech, PSL University, CNRS, Institute of Chemistry for Life and Health Sciences, Laboratory for Inorganic Chemistry, 75005 Paris, France
Email: [email protected]
Metal complexes are currently playing a tremendous role in medicine. For example, the platinum complex
cisplatin and its derivatives oxaliplatin and carboplatin (Fig. 1) are employed in more than 50% of the treatment
regimes for patients suffering from cancer!
Over the last years, our research group focused its attention on the development of novel metal complexes as
imaging and therapeutic agents against cancer and parasitic diseases.1-6 During this talk, we will present our
latest results, including in vivo results, on these topics.
Figure 1. Structures of cisplatin, oxaliplatin and carboplatin.
Acknowledgements
Support for this work was provided by the European Research Council, the Swiss National Science Foundation
through GA 681679, SNSF 205321_157216 and ANR-10-IDEX-0001-02 PSL, respectively.
References
[1] F. W. Heinemann, J. Karges and G. Gasser. Acc. Chem. Res., 2017, 50, 2727.
[2] M. Patra and G. Gasser. Nature Rev. Chem., 2017, 1, 0066, and references therein.
[3] A. Notaro and G. Gasser. Chem. Soc. Rev., 2017, 46, 7317.
[4] M. Patra, K. Zarschler, H.-J. Pietzsch, H. Stephan and G. Gasser. Chem. Soc. Rev., 2016, 45, 6415.
[5] Y. C. Ong, S. Roy, P. C. Andrews and G. Gasser. Chem. Rev., 2019, 119, 730.
[6] M. Brandt, J. Cardinale, M. L. Aulsebrook, G. Gasser and T. L. Mindt. J. Nucl. Med., 2018, 59, 1500.
23
FLUORESCENT SUGARS AND OTHER APPLICATIONS OF BORON PYRROLE COMPLEXES
Penelope J. Brothers
Research School of Chemistry, Australian National University, ACT 2601, Australia Email: [email protected]
In this International Year of the Periodic Table, porphyrins stand out as ligands which can coordinate an
extraordinary number of elements. Most adopt the conventional coordination modes in which the element
resides in the N4 hole of the ligand, the quintessential example being iron porphyrin in hemoglobin. However,
the small, light element boron stands out by being different – two boron atoms can coordinate in the hole as in
the FBOBF porphyrin shown in Fig. 1. We have studied this chemistry extensively with a range of ligands from
the tetrapyrrole family and observe unusual chemistry for both boron and the ligand. For example, a boron
corrole contains a Ph-B-H-B-Ph group threaded through the N4 hole (Fig. 2).
Fig. 1. B2OF2(porphyin)
Fig. 2. B2HPh2(corrole)
More recently, we have used our experience manipulating the chemistry of boron in pyrrole ligands to
investigate new applications of the highly fluorescent BODIPY (which can be imagined as half of a diboron
porphyrin). As an example we have explored the direct connection of O-BODIPY to carbohydrates through B-
O-C links and have produced examples of BODIPY saccharide complexes, shown in cartoon form in Fig. 3.2
We have also incorporated BODIPY into a cobalt complex capable photocatalytic hydrogen production.
Fig. 3. BODIPY-sugar
1. Boron complexes of pyrrolyl Ligands. Brothers, P. J. Inorg. Chem. 2011, 50, 12374-12386.
2. Lighting up sugars: fluorescent BODIPY-gluco-furanose and -septanose conjugates linked by direct B-
O-C bonds. Liu, B.; Novikova, N.; Simpson, M. C.; Timmer, M. S.; Stocker, B. L.; Söhnel, T.; Ware,
D. C.; Brothers, P. J. Org. Biomolec. Chem. 2016, 14, 5205-5209.
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