Metal Complexes with a New Tetrapyridyl Pendant Armed Macrocyclic Ligand.X-ray Crystal Structures of CuII and NiII ComplexesLaura Valencia, Rufina Bastida*, Montserrat Lopez-Deber, Alejandro Macıas, Adolfo Rodrıguez, andManuel Vicente

Santiago de Compostela / Spain, Universidad, Departamento de Quımica Inorganica

Received October 9th, 2002.

Dedicated to Professor Alfonso Castineiras on the Occasion of his 60th Birthday

Abstract. A new pendant-armed macrocyclic ligand, L1, bearingfour pyridyl pendant groups has been synthesized by N-alkylationof the tetraazamacrocyclic precursor L with 2-picolyl chloride hy-drochloride. Metal complexes of L1 have been synthesized andcharacterized by microanalysis, MS-FAB, conductivity measure-ments, IR, UV-Vis, 1H and 13C NMR spectroscopy and magneticstudies. Crystal structures of the ligand L1 as well as of the com-plexes [Ni2L1](ClO4)4·5CH3CN and [Cu2L1](ClO4)4·4.5CH3CN

Metallkomplexe mit einem neuen Tetrapyridyl-armierten makrocyclischen Liganden.Kristallstrukturen von Komplexen mit CuII und NiII

Inhaltsübersicht. Ein neuer seitenarmbestückter makrocyclischerLigand, L1 mit vier Pyridyl-Seitenarmen, wurde durch N-Alkylie-rung des Tetraazamakrocyclus L mit 2-Picolylchlorid-Hydrochloridsynthetisiert. Metallkomplexe von L1 wurden hergestellt und durchMikroanalysen, MS-FAB-Spektrometrie, Leitfähigkeitsmessungen,IR-, UV-Vis-, 1H- und 13C-NMR-Spektroskopie sowie magneto-

1 Introduction

The polyfunctional macrocyclic ligands display a specificcoordination behaviour, highly selective and pH dependent,and form stable complexes with a large variety of metal ions[13]. The stability of the chelates depends on the relativedimensions of both the macrocyclic cavity and the ionicradius of the metal, as well as on the degree of flexibility ofthe ligand and the number and nature of their donor atoms.In previous work we have reported the coordination behav-iour of the pendant armed macrocyclic ligands L2 and L3

(Chart 1) derived from the same N6-donor 18-memberedmacrocycle [4, 5]. Different macrocyclic disposition hasbeen found for the tetracyanomethylated macrocyclic ligandL2 in relation to the metal ion employed and even whendifferent salts of the same metal are used. The X-ray studiesshow the presence of two metal atoms within the macro-cyclic ligand in the nitrate and perchlorate silver complexes

* Dr. R. BatistaDepartamento de Quımica InorganicaFacultad de QuımicaAvenida de las Ciencias s/n15782 Santiago de Compostela, Spain.Fax: 00 34 981597525e-mail: qibastid@usc.es

268 2003 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim 00442313/03/629/268274 $ 20.00.50/0 Z. Anorg. Allg. Chem. 2003, 629, 268274

have been determined by single crystal X-ray crystallography. TheX ray studies show the presence of two metal atoms within themacrocyclic ligand in both metal complexes showing five coordi-nation arrangement for the metal ions.

Keywords: Copper; Nickel; Zinc; Macrocyclic ligands; Crystalstructure

chemisch charakterisiert. Die Kristallstrukturen von L1 und derKomplexe [Ni2L1](ClO4)4·5CH3CN und [Cu2L1](ClO4)4·4,5CH3CNwurden anhand von Einkristallen ermittelt. Die Strukturen zeigendie Anwesenheit zweier Metallatome innerhalb des Makrocyclusmit Fünffach-Koordination an den Metallionen.

Metal Complexes with a New Tetrapyridyl Pendant Armed Macrocyclic Ligand.

showing a monomeric and a polymeric nature, respectively.The crystal structure of the zinc nitrate complex shows alsoa mononuclear endomacrocyclic nature. The tetrapyridylpendant armed macrocyclic ligand L3 is able to form monoand/or dinuclear metal complexes with transitional andpostransitional metal ions, and whilst with AgI a dinuclearendomacrocyclic complex was obtained, when the metal ionused was CuII, mononuclear and dinuclear complexes werepossible to obtain, and the X-ray diffraction studies revealan endomacrocyclic coordination for the mononuclearcomplex whilst the dinuclear complex has both metal ionsout from the macrocyclic cavity. In this case, we have pre-pared the new tetrapyridyl pendant armed macrocycle L1.It has been synthesized by the N-alkylation of the N6-donor20-membered macrocycle L, obtained from a [22] tem-plate reaction between 2,6-diformylpyridine and 1,5-diaza-pentane, and we have found that the complexation reactionsbetween L1 and transitional and postransitional metal ionsgive rise to di or trinuclear metal complexes, but mononuc-lear complexes could not be obtained.

2 Results and Discussion

The metal-free macrocyclic ligand L was synthesized by the[22] barium(II) templated cyclocondensation of 2,6-difor-mylpyridine and 1,3-propilendiamine in methanol followedby an in situ reductive demetallation of the Schiff basemacrocyclic barium(II) complex using excess sodiumborohydride as has been described previously [6]. The li-gand L1 has been synthesized by the N-alkylation of thesecondary aromatic amines present in the ligand L, using2-picolyl chloride hydrochloride in acetonitrile as describedin the experimental section. The macrocycle was charac-terized by elemental analysis, IR, NMR (1H and 13C) andFAB MS. The IR spectrum showed no bands adscribable

Table 1 1H and 13C NMR spectra for L1, [Zn3L1](ClO4)6·4H2O and [Cd3L1](ClO4)6·2H2O in CD3CN

L1 [Zn3L1](ClO4)6·4H2O [Cd3L1](ClO4)6·2H2O

1H 13C 1H 13C 1H 13C

Assign. δ/ppm Assign. δ/ppm Assign. δ/ppm Assign. δ/ppm Assign. δ/ppm Assign. δ/ppm

H1 7.43 (t, 4H) C1 136.6 C1 144.5 H1 7.94 (t, 2H) C1 143.0H2 7.14 (d, 8H) C2 121.1 C2 126.0 H2 7.26 (d, 4H) C2 122.2

C3 158.7 C3 155.4 C3 155.5H4 3.73 (s, 8H) C4 61.2 H4a 4.57 (d, 4H) C4 62.6 H4 4.214.32 (m, 8H) C4 63.3

H4b 4.41 (d, 4H)H5 2.44 (t, 8H) C5 51.6 H5a 2.74 (m, 4H) C5 57.0 H5a 2.592.67 (m, 4H) C5 57.7

H5b 2.87 (m, 4H) H5b 2.842.89 (m, 4H)H6 1.69 (q, 4H) C6 22.4 H6a 0.96 (m, 4H) C6 27.4 H6 0.981.02 (m, 4H) C6 26.3

H6b 1.24 (m, 4H)H7 3.57 (s, 8H) C7 59.6 H7a 4.29 (d, 4H) C7 59.3 H7a 3.96 (d, 4H) C7 58.0

H7b 4.05 (m, 4H) H7b 4.11 (d, 4H)C8 160.1 C8 155.3 C8 155.2

H9 7.45 (d, 4H) C9 122.7 7.377.42 (m, 8H) C9 123.7 H9 7.60 (d, 4H) C9 125.7H10 7.59 (t, 4H) C10 136.3 H1,H2, 7.62 (d, 4H) C10 142.4 H10 8.06 (t, 4H) C10 141.2

H9,H10,H11,H12

H11 7.08 (t, 4H) C11 121.8 7.978.07 (m,10H) C11 126.2 H11 7.46 (t, 4H) C11 125.2H12 8.46 (d, 4H) C12 149.0 C12 149.3 H12 8.26 (d, 4H) C12 150.0

Z. Anorg. Allg. Chem. 2003, 629, 268274 269

to the secondary amines confirming that the alkylation re-action took place. The spectrum also shows two splittingbands with maxima at 1590, 1572 and 1459, 1435 cm1, inthe region associated with the appearance of the ν(CN)and ν(CC) vibrations from the pyridine groups. The FABMS gave a parent peak at m/z 719 [L1 1] correspondingto the incorporation of four pyridyl pendant groups in themacrocycle L.

The 1H and 13C NMR spectra of L1 (Table 1) have beenrecorded using deuterated acetonitrile as solvent, and con-firm the integrity of the ligand and its stability in solution.The assignment of the proton signals was based uponstandard 2D homonuclear (COSY) and 1H/13C heteronu-clear spectra (HMQC). The aliphatic protons of the ligandH4a/H4b and H7a/H7b, appear as singlet signals at 3.73 and2.57 ppm, respectively, whilst H5a/H5b and H6a/H6b appearsas a triplet and a quadruplet signals at 2.44 and 1.69 ppm,respectively. The aromatic region of the spectrum is consis-tent with the presence of a triplet and a doublet from thepyridine backbone hydrogen atoms, and two triplets andtwo doublets from the pyridine pendants hydrogen atoms.

The X-ray crystal structure of the ligand L1, recrys-tallized from acetonitrile, confirms the incorporation of thefour pendant groups in the macrocyclic framework. Themolecular structure is given in Figure 1 together with bondlengths. The bond lengths and angles do not show any sig-nificant deviations from the expected values. The macro-cyclic ring is completely bent in contrast with the relatedmacrocyclic ligands L2 and L3, which have a markedlystepped conformation [4, 5]. In L1 the pyridyl rings (r.m.s.deviation from planarity, 0.0123 A) are almost coplanarforming a dihedral angle of 7.4°. As in L2 and L3, the crys-tal structure reveals an intramolecular π-stacking interac-tion between the pyridine rings of the macrocyclic ligand.In this case, the intramolecular distance between the centro-

L. Valencia, R. Bastida, M. Lopez-Deber, A. Macıas, A. Rodrıguez, M. Vicente

Figure 1 Crystal structure and bond lengths/A for L1.

C(1)N(1) 1.350(3), C(1)C(2) 1.382(4), C(1)C(8) 1.513(3), C(2)C(3)1.388(4), C(3)C(4) 1.378(4), C(4)C(5) 1.380(4), C(5)N(1) 1.353(3),C(5)C(6) 1.512(4), C(6)N(2) 1.474(3), C(7)N(2) 1.474(3),C(7)C(10)#1 1.525(4), C(8)N(3) 1.468(3), C(9)N(3) 1.468(3),C(9)C(10) 1.528(4), C(10)C(7)#1 1.525(4), C(11)N(2) 1.468(3),C(11)C(12) 1.507(3), C(12)N(4) 1.344(3), C(12)C(13) 1.388(4),C(13)C(14) 1.378(4), C(14)C(15) 1.378(4), C(15)C(16) 1.374(4),C(16)N(4) 1.338(3), C(17)N(3) 1.458(3), C(17)C(18) 1.506(4),C(18)N(5) 1.331(3), C(18)C(19) 1.382(4), C(19)C(20) 1.380(4),C(20)C(21) 1.367(4), C(21)C(22) 1.367(4), C(22)N(5) 1.340(4).

ids of the pyridine rings is 4.04 A, being shorter than inthe previous ligands. The macrocycle shows all the pendantgroups lying on the same side of the great ring.

The metal complexes of L1 were synthesized by reactionof the ligand and the appropriate metal salt in refluxingacetonitrile in a 1:2.5 molar ratio as described in the Experi-mental Section. Attempts to obtain mononuclear com-plexes with L1 using a 1:1 molar ratio between the ligandand the metal ion were not successful and the free ligandwas obtained in all cases. The complexes were characterizedby elemental analysis, IR, NMR (1H and 13C) and FABMS. The elemental analysis shows the presence of dinuclearmetal complexes in most cases, with formula:[M2L1](X)4·yH2O·zCH3CN for M: CdII, NiII, ZnII (X:NO3

) and M: CuII, NiII (X: ClO4). Nevertheless they re-

vealed the presence of trinuclear complexes with formula[M3L1](ClO4)6·xH2O for M: Cd2, Zn2.

The IR spectra of the complexes showed no bands corres-ponding to secondary amine present in the ligand con-firming the alkylation of all the secondary amine groupspresent in the ligand. The bands ca. 1610 and 1455 cm1

are associated with ν(CN) and ν(CC) vibrations fromthe pyridyl rings [7], which undergo a shift towards highfrequencies on complexation, suggesting an interaction be-tween the metal and the pyridine nitrogen atoms [8].

For the perchlorate complexes different results have beenfound in relation with the bands attributable to the per-chlorate absorptions. For [Zn3L1](ClO4)6·4H2O and[Cd3L1](ClO4)6·2H2O complexes, the splitting of bands at1100 and 626 cm1 suggests the coordination of some per-chlorate groups to the metal ions. For[Cu2L1](ClO4)4·4CH3CN and [Ni2L1](ClO4)4·2CH3CN onlytwo perchlorate absorptions were observed in the spectra,

Z. Anorg. Allg. Chem. 2003, 629, 268274270

one centered ca. 1100 (ν3) and the other ca. 630 cm1 (ν4).The lack of splitting of these bands indicates the presenceof ionic perchlorate anions [9, 10], without coordination tothe metal atom. This result is supported by the conductancemeasurements of the complexes in acetonitrile. The molarconductance values for all the perchlorate complexes, meas-ured in acetonitrile at 25 °C are in the range characteristicof 4:1 electrolytes [11], suggesting that in[Zn3L1](ClO4)6·4H2O and [Cd3L1](ClO4)6·2H2O complexes,two perchlorate ions are coordinated to the metal ions, andthey are no-coordinated in [Cu2L1](ClO4)4·4CH3CN and[Ni2L1](ClO4)4·2CH3CN complexes. These results are alsoin accordance with the X-ray structural analysis of the[Ni2L1](ClO4)4·5CH3CN and [Cu2L1](ClO4)4·4.5CH3CNcomplexes, where the metal ions are coordinated to the do-nor atoms from the macrocyclic ligand and the perchlorateanions are not involved in coordination.

For the nitrate complexes the presence of several bandsin the region associated with nitrate vibrations clearly ident-ifies these species as containing co-ordinated nitrate groups[1214]. The vibrations associated with a coordinated ni-trate were noted together with a band arising from ionicnitrate. These results are also supported by the conductancemeasurements of the complexes in acetonitrile. The molarconductivities indicated that all the nitrate complexes are3:1 electrolytes ([Ni2L1](NO3)4·2CH3CN, [Zn2L1](NO3)4-·4H2O and [Cd2L1](NO3)4·3CH3CN·2H2O) in that solventsuggesting the coordination of one or two nitrate ions tothe metal atoms.

Positive-ion FAB mass spectrometry indicates the pre-sence of the macrocyclic ligand and metal ions, and as it iscommon with complexes of this type, a characteristic frag-mentation pattern resulting from stepwise loss of coun-terions from the neutral parent ion is observed.

The FAB mass spectra of the dinuclear complexes showpeaks assignable to [M2L1(X)3] in all cases, and all as-signed peaks show the isotopic contribution of the metals.

In the complexes [Cu2L1](ClO4)4·4CH3CN and[Zn2L1](NO3)4·4H2O peaks assigned to species such as[M4L1(X)5], [M3L1(X)5], [M3L1(X)4] are also present inthe spectra, which can be due to oligomerisation within thematrix under the conditions of the FAB experiment, al-though it also could be indicative of the polymeric natureof the compound.

For the ZnII trinuclear complex a fragment assigned tothe specie [Zn3L1(ClO4)5], containing three metal ions ispresent, whilst for the CdII trinuclear complex only onepeak at m/z 1244 attributable to [Cd2L1(ClO4)3] is presentin the spectrum.

The UV-Vis spectra were registered for the NiII, CoII andCuII complexes.

The solid-state electronic spectrum of[Ni2L1](NO3)4·2CH3CN shows bands at 10870 (ν1), 17182(ν2) and 28011 cm1 (ν3). These values are well within therange for octahedral NiII complexes, and the bands can ac-cordingly be attributed to 3A2g3T2g(F), 3A2g3T1g(F)and 3A2g3T1g(P) transitions [15].

Metal Complexes with a New Tetrapyridyl Pendant Armed Macrocyclic Ligand.

Nevertheless the electronic spectrum of[Ni2L1](ClO4)4·2CH3CN shows bands in the 26300 and17000 cm1 regions which could be assigned to3B1(F)3E(F) and 3B1(F)A2,3E(P) transitions, respec-tively. This values are consistent with a pentacoordinate en-vironment around NiII [16].

The electronic reflectance spectrum for[Cu2L1](ClO4)4·4CH3CN consists of two equally intensepeaks at ca.12000 and 16000 cm1, that are similar to thosedescribed in the literature for five coordinated CuII com-plexes [17]. That is in agreement with the X-ray crystalstructure.

The room temperature effective magnetic moment of[Ni2L1](NO3)4·2CH3CN (5.1 BM) is in agreement with thepresence of a dinuclear octahedral NiII complex. The valueis of 4.4 BM for [Ni2L1](ClO4)4·2CH3CN indicating thepresence of a dinuclear five coordinated NiII complex. Thisresult supports the evidence of the reflectance spectrum andis in agreement with the crystal structure. The room tem-perature effective magnetic moment of[Cu2L1](ClO4)4·4CH3CN (2.9 BM) lies within the rangeusually observed for a dinuclear five coordinated CuII com-plexes [18].

The 1H NMR spectra of the diamagnetic complexes[Zn3L1](ClO4)6·4H2O and [Cd3L1](ClO4)6·2H2O recorded inCD3CN, are listed in Table 1. The assignments for the spec-tra correspond to the labeling shown in Chart 2.

The aromatic region of the 1H NMR spectrum of[Zn3L1](ClO4)6·4H2O shows three multiplets correspondingto the pyridyl H1 and H2 and to the aromatic protons fromthe pendant groups (H9-H12). A complete assignment of thearomatic protons was not possible. The 1H signals from theCH2 groups are not equivalent in the complex, and H4a,H4b, H7a and H7b appear as four doublets at 4.57, 4.41, 4.29and 4.05 ppm; and H5a and H5b appear as two multipletsat 2.74 and 2.87 ppm whilst the remaining two multipletsthat appear at 0.96 and 1.24 ppm are assigned to H6a and

Z. Anorg. Allg. Chem. 2003, 629, 268274 271

H6b respectively. The 1H NMR spectra of the complexesshowed, in general, downfield shifts of signals when com-pared with the free ligand due to the coordination to themetal atoms.

The 1H NMR spectrum of [Zn2L1](NO3)4·4H2O inCD3CN could not be fully assigned because of its com-plexity. The large number of signals indicated that the li-gand has lost its 4-fold symmetry, or may be due to thepresence of several species in solution.

The 1H NMR spectrum of [Cd3L1](ClO4)6·2H2O re-corded in CD3CN shows as in the [Zn3L1](ClO4)6·4H2Ospectrum the coordination of the nitrogen donor atoms tothe metal ions. The proton signals from the macrocyclicbackbone and the pendant groups are shifted downfieldwhen compared with the free ligand. Again the CH2 pro-tons are not equivalent as in the free ligand and differentsignals have been found for each one of H4a, H4b, H5a, H5b,H6a, H6b, H7a and H7b.

The 1H NMR spectrum of [Cd2L1](NO3)4·3CH3CN-·2H2O is very similar to the previous CdII complex showingthat both have the same conformation in solution.

Crystal structure of [Ni2L1](ClO4)4·5CH3CN

Crystals of [Ni2L1](ClO4)4·5CH3CN were grown by slowrecrystallisation of [Ni2L1](ClO4)4·2CH3CN from an aceto-nitrile solution. The molecular structure of the cationic unit[Ni2L1]4 is given in Figure 2 together with selected bond

Figure 2 Crystal structure and selected bond lengths/A andangles/° for [Ni2L1](ClO4)4·5CH3CN

N(1)Ni(1) 1.945(3), N(2)Ni(1) 2.114(2), N(3)Ni(2) 2.117(2),N(4)Ni(2) 1.952(3), N(5)Ni(2) 2.105(3), N(6)Ni(1) 2.109(2),N(7)Ni(1) 2.030(2), N(8)Ni(2) 2.022(2), N(9)Ni(2) 2.037(3),N(10)Ni(1) 2.032(3), N(1)Ni(1)N(7) 162.39(10), N(1)Ni(1)N(10)94.59(10), N(7)Ni(1)N(10) 92.17(10), N(1)Ni(1)N(6) 83.16(10),N(7)Ni(1)N(6) 114.04(10), N(10)Ni(1)N(6) 80.34(10),N(1)Ni(1)N(2) 81.09(10), N(7)Ni(1)N(2) 81.32(10),N(10)Ni(1)N(2) 115.12(10), N(6)Ni(1)N(2) 158.68(10),N(4)Ni(2)N(8) 162.04(10), N(4)Ni(2)N(9) 97.09(11),N(8)Ni(2)N(9) 92.09(10), N(4)Ni(2)N(5) 82.56(11),N(8)Ni(2)N(5) 114.32(10), N(9)Ni(2)N(5) 80.21(11),N(4)Ni(2)N(3) 81.25(10), N(8)Ni(2)N(3) 80.82(10),N(9)Ni(2)N(3) 117.68(10), N(5)Ni(2)N(3) 157.19(10).

L. Valencia, R. Bastida, M. Lopez-Deber, A. Macıas, A. Rodrıguez, M. Vicente

lengths and angles relating to the coordination environmentof the metal ions. Bond lengths and angles in the structureare all within the normal ranges. The X-ray crystal structureconfirms the presence of a dinuclear complex being bothmetal ions sited into the macrocyclic cavity. Both metal ionsare in a very similar sligtly distorted square pyramidal en-vironment arising from coordination by five nitrogen atomsfrom the macrocyclic ligand. Each metal ion is coordinatedby one nitrogen atom from the pyrine rings from the macro-cyclic backbone, by two amine nitrogen atoms and by twonitrogen atoms from the pyridyl pendant groups attachedto those amine nitrogen atoms. The pyridinic nitrogenatoms N(1) and N(9) provide the shortest distances to themetal ions (N(1)Ni(1) 1.945(3), N(4)Ni(2) 1.952(3)). Inthe present case, where the nickel atoms are both five coor-dinated by five macrocycle N atoms, it is possible to use theindex of trigonality formula to show that the arrangementat Ni(1) is clearly square pyramidal with τ 0.06. Thepolyhedron is such that the amine nitrogen atom N(10) isat the apex and the base is provided by the planeN(1)N(2)N(6)N(7) which has a r.m.s deviation from planar-ity of 0.1194 A. Applying the same criteria to Ni(2) gives avery similar result. The surrounding at Ni(2) is also squarepyramidal with τ 0.08. The nitrogen atom N(9) is at theapex and the base is provided by the planeN(3)N(4)N(5)N(8) which has a r.m.s deviation from planar-ity of 0.1196 A. The nitrogen atoms sited in the apex of thesquare pyramide N(10) and N(9) belongs to one pyridylpendant group in both square pyramids. The nickel atomsare 5.70 A apart showing no interaction between them. Themacrocycle is bent, and the pyridyl rings (r.m.s. deviationfrom planarity, 0.0111 and 0.0081 A) form a dihedral angleof 30.32°. As in the free ligand, the crystal structure revealsan intramolecular π-stacking interaction between the pyri-dyl rings of the macrocyclic ligand. The intramolecular dis-tance between the centroids of the pyridyl rings is 4.15 A.

Crystal structure of [Cu2L1](ClO4)4·4.5CH3CN

By slow recrystallisation of [Cu2L1](ClO4)4·4CH3CN froman acetonitrile solution crystals with formula[Cu2L1](ClO4)4·4.5CH3CN were obtained. The molecularstructure of the cationic unit [Cu2L1]4 is given in Figure 3together with selected bond lengths and angles relating tothe coordination environment of the metalions. The crystalstructure is very similar to that obtained for[Ni2L1](ClO4)4·5CH3CN. Both copper ions are sited intothe macrocyclic cavity, and are again five coordinated in avery similar slightly distorted square pyramidal environ-ment. The macrocyclic ligand is again bent with a dihedralangle between the pyridyl rings (r.m.s. N(1)C(5) 0.0138and N(4)C(15) 0.0078 A) of 29.83° and an intramolecularπ-stacking interaction between the pyridyl rings of themacrocyclic ligand also exists, being 4.18 A the intramole-cular distance between the centroids of the rings. As in theprevious structure the arrangement at copper atoms isclearly square pyramidal with τ 0.10 for Cu(1) and τ

Z. Anorg. Allg. Chem. 2003, 629, 268274272

Figure 3 Crystal structure and selected bond lengths/A andangles/° for [Cu2L1](ClO4)4·4.5CH3CN

N(1)Cu(2) 1.891(9), N(2)Cu(2) 2.136(8), N(3)Cu(1) 2.121(8),N(4)Cu(1) 1.886(9), N(5)Cu(1) 2.056(8), N(6)Cu(2) 2.064(8),N(7)Cu(2) 2.191(10), N(8)Cu(1) 2.202(9), N(9)Cu(1) 1.958(8),N(10)Cu(2) 1.925(9), N(4)Cu(1)N(9) 165.1(4),N(4)Cu(1)N(5)82.4(4), N(9)Cu(1)N(5) 82.7(4), N(4)Cu(1)N(3) 83.2(4),N(9)Cu(1)N(3) 111.3(4), N(5)Cu(1)N(3) 158.8(3),N(4)Cu(1)N(8) 93.4(3), N(9)Cu(1)N(8) 92.9(3), N(5)Cu(1)N(8)118.4(3), N(3)Cu(1)N(8) 77.9(3), N(1)Cu(2)N(10) 164.3(4),N(1)Cu(2)N(6) 82.1(4), N(10)Cu(2)N(6) 82.2(4), N(1)Cu(2)N(2)83.0(4), N(10)Cu(2)N(2) 112.1(4), N(6)Cu(2)N(2) 157.5(4),N(1)Cu(2)N(7) 97.9(4), N(10)Cu(2)N(7) 90.0(4), N(6)Cu(2)N(7)122.0(4), N(2)Cu(2)N(7) 76.8(4).

0.11 for Cu(2) where each metal ion is coordinated by onenitrogen atom from the pyrine rings from the macrocyclicbackbone, by two amine nitrogen atoms and by two nitro-gen atoms from the pyridyl pendant groups attached tothose amine nitrogen atoms. The pyridinic nitrogen atomsN(1) and N(4) provide the shortest distances to the metalions (N(1)Cu(2) 1.891(9), N(4)Cu(1) 1.886(9)). The ni-trogen atom N(8) is at the apex of the square pyramidaround Cu(1) and the base is provided by the planeN(3)N(4)N(5)N(9) which has a r.m.s deviation from planar-ity of 0.1295 A. The nitrogen atom N(7) is at the apex ofthe square pyramid around Cu(2) and the base is providedby the plane N(1)N(2)N(6)N(10) which has a r.m.s devi-ation from planarity of 0.1387 A. There is no interactionbetween the metal atoms being the distance Cu(1)Cu(2)5.711 A.

3 Experimental

3.1 Synthetic Procedures

Chemicals and Starting Materials: Compound L was synthesizedas described [6]; 2,6-pyridinedimethanol, 1,3-propilendiamine,2-picolyl chloride hydrochloride and metal salts were commercialproducts (from Alfa and Aldrich) and were used without furtherpurifications. Solvents were of reagent grade and were purified bythe usual methods. Caution: Perchlorate salts are potentially explo-sive!

Metal Complexes with a New Tetrapyridyl Pendant Armed Macrocyclic Ligand.

3.2 Synthesis of L1.

L (2 mmol, 0.71 g) was dissolved in acetonitrile (40 mL) under re-flux and 2-picolyl chloride hydrochloride (11 mmol, 1.80 g) andNa2CO3 (20 mmol, 2.12 g) were added. The mixture was refluxedfor eight hours and stand to cool. The solution was filtered off andevaporated to dryness. The residue was then extracted with water-chloroform. The organic layer was dried over MgSO4 and evapo-rated to yield an orange solid that was recrystallised in acetonitrilegiving the ligand L1 as a white solid.C44H50N10 (718.9); C, 73.7 (calc. 73.5); H, 6.9 (7.0); N, 19.7(19.5) %. Yield: 37 %.IR (KBr, cm1): ν(CC)ar and ν(CN)py 1590, 1459. (FAB, m/z):[L1H] 719. Colour: white.

3.3 General procedure for the preparation ofcomplexes

To an acetonitrile solution (20 mL) of L1 (0.07 mmol, 0.1205 g) wasadded a solution of the appropriate metal salt (0.175 mmol) inacetonitrile (10 mL) and the solution was heated at reflux for 4hours and stand to cool. The solucion was concentrated until ca.10 mL. The product obtained was filtered off and dried under vacu-um. The complexes were found to be air-stable and soluble inacetonitrile, dimethyl sulfoxide and dimethyl formamide, some ofthem are soluble in water, and are in general insoluble in absoluteethanol, methanol, diethyl ether, chloroform, dichloromethaneand acetone.

3.4. L1 complexes

3.4.1 [Ni2L1](NO3)4·2CH3CNC48H56N16O12Ni2 (1166.5); C, 49.2 (calc. 49.4); H, 5.0 (4.8); N, 18.9(19.2) %. Yield: 36 %. IR (KBr, cm1): ν(CC)ar and ν(CN)py

1607, 1588, 1460, 1442, [ν(NO3)] 728, 836, 1024, 1285, 1383, 1498.

MS (FAB, m/z): [Ni2L1(NO3)3] 1020, [NiL1(NO3)] 838, [NiL1]

776. ΛM (103 M, DMF): 268 Ω1cm2mol1 (3:1 electrolyte). Col-our: blue

3.4.2 [Ni2L1](ClO4)4·2CH3CNC48H56N12Cl4O16Ni2 (1316.2); C, 44.3 (calc. 43.8); H, 4.3 (4.3); N,12.7 (12.8) %. Yield: 47 %. IR (KBr, cm1): ν(CC)ar and ν(C

N)py 1608, 1583, 1461, 1444, [ν(ClO4)] 1088, 625. MS (FAB, m/z):

[Ni2L1(ClO4)3] 1131, [Ni2L1(ClO4)2] 1035. ΛM (103 M, DMF):430 Ω1cm2mol1 (4:1 electrolyte). Colour: blue.

3.4.3 [Cu2L1](ClO4)4·4CH3CNC52H62N14Cl4O16Cu2 (1408.1); C, 44.3 (calc. 44.4); H, 4.5 (4.4); N,13.7 (13.9) %. Yield: 46 %. IR (KBr, cm1): ν(CC)ar and ν(C

N)py 1608, 1583, 1460, 1442, [ν(ClO4)] 1088, 627. MS (FAB, m/z):

[Cu4L1(ClO4)6] 1564, [Cu4L1(ClO4)5] 1469, [Cu3L1(ClO4)5]

1406, [Cu3L1(ClO4)4] 1307,[Cu3L1(ClO4)3] 1208,[Cu2L1(ClO4)3] 1143, [Cu2L1(ClO4)2] 1045, [Cu2L1(ClO4)] 945,[Cu2L1] 846, [CuL1] 781. ΛM (103 M, DMF): 462Ω1cm2mol1 (4:1 electrolyte). Colour: blue.

3.4.4 [Zn2L1](NO3)4·4H2OC44H58N14O16Zn2 (1169.8); C, 45.4 (calc. 45.2); H, 4.8 (5.0); N,16.9 (16.8) %. Yield: 38 %. IR (KBr, cm1): ν(CC)ar and ν(C

N)py 1607, 1580, 1460, 1442 [ν(NO3)] 746, 834, 1021, 1295, 1384,

Z. Anorg. Allg. Chem. 2003, 629, 268274 273

1462. MS (FAB, m/z): [Zn4L1(NO3)5] 1297, [Zn3L1(NO3)4] 1163,[Zn2L1(NO3)4] 1094, [Zn2L1(NO3)3] 1032, [ZnL1(NO3)] 844.ΛM (103 M, DMF): 251 Ω1cm2mol1 (3:1 electrolyte). Colour:white

3.4.5 [Zn3L1](ClO4)6·4H2OC44H58N10Cl6O28Zn3 (1583.9); C, 33.3 (calc. 33.4); H, 3.8 (3.7); N,8.7 (8.8) %. Yield: 42 %. IR (KBr, cm1): ν(CC)ar and ν(CN)py

1608, 1581, 1460, 1444, [ν(ClO4)] 1088, 1114, 1145, 636, 627. MS

(FAB, m/z): [Zn3L1(ClO4)5] 1417, [Zn2L1(ClO4)3] 1153,[Zn2L1(ClO4)2] 1054, [ZnL1(ClO4)] 881. ΛM (103 M, DMF):482 Ω1cm2mol1 (4:1 electrolyte). Colour: white.

3.4.6 [Cd2L1](NO3)4·3CH3CN·2H2OC50H63N17O14Cd2 (1350.9); C, 44.0 (calc. 44.5); H, 4.9 (4.7); N,17.6 (17.6) %. Yield: 37 %. IR (KBr, cm1): ν(CC)ar and ν(C

N)py 1603, 1581, 1460, 1442, [ν(NO3)] 738, 838, 1017, 1288, 1384,

1480. MS (FAB, m/z): [Cd2L1(NO3)3] 1129, [CdL1(NO3)] 894.ΛM (103 M, DMF): 265 Ω1cm2mol1 (3:1 electrolyte). Colour:white

3.4.7 [Cd3L1](ClO4)6·2H2OC44H54N10Cl6O26Cd3 (1688.9); C, 31.1 (calc. 31.3); H, 3.4 (3.2); N,8.2 (8.3) %. Yield: 43 %. IR (KBr, cm1): ν(CC)ar and ν(CN)py

1603, 1580, 1461, 1442, [ν(ClO4)] 1088, 1114, 1145, 636, 627. MS

(FAB, m/z): [Cd2L1(ClO4)3] 1244. ΛM (103 M, DMF): 453Ω1cm2mol1 (4:1 electrolyte). Colour: white.

3.5 Physical measurements

Elemental analysis were performed in a Carlo-Erba EA microana-lyser. Infra-red spectra were recorded as KBr discs on a BrukerIFS-66V spectrophotometer. FAB mass spectra were recordedusing a Kratos-MS-50T spectrometer connected to a DS90 datasystem using 3-nitrobenzyl alcohol as the matrix. Conductivitymeasurements were carried out in 103 mol dm3 DMF solutionsat 20 °C using a WTW LF3 conductivimeter. 1H and 13C NMRspectra were recorded on a Brucker AMX 300 MHz instrumentagainst TMS as internal standard and DEPT 135 and HMQC 1H-13C on a Bruker 500 MHz. Solid state electronic spectra were re-corded on a Hitachi 4-3200 spectrophotometer using MgCO3 asreference. Magnetic studies were determined at r.t. on a vibrationsample magnetometer (VSM) Digital Measurement System 1660with a magnetic field of 5000 G.

3.6 Crystal structure data and determination for L1,[Ni2L1](ClO4)4·5CH3CN and[Cu2L1](ClO4)4·4.5CH3CN

The crystals were obtained by slow recrystallisation from aceto-nitrile in all cases. The details of the X-ray crystal data, and thestructure solution and refinement are given in Table 2. Measure-ments were made on a Bruker SMART CCD area diffractometerwith graphite-monochromated Mo-Kα radiation. All data werecorrected for Lorentz and polarization effects. Absorption correc-tions (empirical) [19] were applied for all crystal structures. Com-plex scattering factors were taken from the program packageSHELXTL [20]. The structures were solved by direct methods,which revealed the position of all non-hydrogen atoms. All thestructures were refined on F2 by a full-matrix least-squares pro-cedure using anisotropic displacement parameters for all non hy-drogen atoms. The hydrogen atoms were located in their calculated

L. Valencia, R. Bastida, M. Lopez-Deber, A. Macıas, A. Rodrıguez, M. Vicente

Table 2 Crystal data and structure refinement for L1, [Ni2L1](ClO4)4·5CH3CN and [Cu2L1](ClO4)4·4.5CH3CN

L1 [Ni2L1](ClO4)4·5CH3CN [Cu2L1](ClO4)4·4.5CH3CN

Empirical formula C44 H50 N10 C54 H65 Cl4 N15 O16 Ni2 C53 H63.5 Cl4 N14.5 O16 Cu2

Formula weight 718.94 1459.56 1414.96Temperature 293(2) K 293(2) K 293(2) KWavelength 0.71073 A 0.71073 A 0.71073 ACrystal system monoclinic triclinic triclinicSpace group C2/c P1 P1Unit cell dimensions a 15.169(5) A a 12.888(4) A α 98.013(5)° a 12.878(5) A α 98.193(8)°

b 12.186(4) A β 105.800(6)° b 14.356(4) A β104.186(5)° b 14.812(6) A β103.281(7)°c 21.598(7) A c 20.020(6) A γ114.893(4)° c 19.867(8) A γ114.548(8)°

Volume 3841(2) A3 3131.2(16) A3 3231(2) A3

Z 4 2 2Density (calculated) 1.243 Mg/m3 1.527 Mg/m3 1.802 Mg/m3

Absorption coefficient 0.076 mm1 0.851 mm1 0.899 mm1

Crystal size 0.51 x 0.18 x 0.07 mm3 0.77 x 0.40 x 0.20 mm3 0.42 x 0.19 x 0.04 mm3

Theta range for data collection 1.96 to 26.51° 1.09 to 26.39° 1.09 to 23.26°Index ranges 18h18, 0k15, 0l26 16h15, 17k17, 0l25 14h13, 16k16, 0l22Reflections collected 11827 34855 15302Independent reflections 4113 [R(int) 0.0568] 12696 [R(int) 0.0319] 9228 [R(int) 0.0802]Completeness to theta 98.4 % (26.51°) 99.0 %(26.39°) 99.4 % (23.26°)Absorption correction Empirical Empirical EmpiricalMax. and min. transmission 0.9947 and 0.9621 0.8482 and 0.5602 0.9649 and 0.7039Refinement method Full-matrix least-squares on F2 Full-matrix least-squares on F2 Full-matrix least-squares on F2

Data / restraints / parameters 4113 / 0 / 244 12696 / 0 / 825 9228 / 0 / 826Goodness-of-fit on F2 1.051 1.056 0.964Final R indices [I>2sigma(I)] R1 0.0487, wR2 0.1102 R1 0.0466, wR2 0.1231 R1 0.0813, wR2 0.1941R indices (all data) R1 0.1312, wR2 0.1534 R1 0.0646, wR2 0.1395 R1 0.2010, wR2 0.2668Largest diff. peak and hole 0.206 and 0.269 e·A3 1.545 and 0.981 e·A3 0.703 and 0.491 e·A3

positions and refined using a riding model. Molecular graphicswere generated using ORTEP-3 [21].Crystallographic data (excluding structure factors) for the struc-tures reported in this paper have been deposited with the Cam-bridge Crystallographic Data Centre as supplementary publication:CCDC 194900 for L1, CCDC 194901 for [Ni2L1](ClO4)4·5CH3CNand CCDC 194902 for [Cu2L1](ClO4)4·4.5CH3CN. Copies of thedata can be obtained free of charge on application to the CCDC,12 Union Road, Cambridge CB2 IEZ, U.K. [Fax: (internat.) 44(0)1223 336033; E-mail: deposit@ccdc.cam.ac.uk]. CCDC194900-194902

Acknowledgments. We thank Xunta de Galicia(PGIDT01PXI20901PR) for financial support.Intensity measurements were performed at the Unidade de RaiosX. RIAIDT. University of Santiago de Compostela. SPAIN.

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