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Inorganica Chimica Acta 317 (2001) 45–52

Synthesis and characterisation of silver, zinc and cadmiumcompounds with an N3O2 Schiff base macrocycle: the crystal andmolecular structures of the silver(I) and cadmium(II) complexes

Laura Valencia a, Harry Adams b, Rufina Bastida a,*, David E. Fenton b,Alejandro Macıas a

a Departamento de Quımica Inorganica, Uni�ersidad de Santiago, 15706 Santiago de Compostela, Spainb Department of Chemistry, The Uni�ersity of Sheffield, Sheffield S3 7HF, UK

Received 11 August 2000; accepted 8 January 2001

Abstract

The metal-templated cyclocondensation of 2,6-diformylpyridine and 1,4-bis(2-aminophenoxy)butane in the presence of silver(I),zinc(II) and cadmium(II) salts gave the following di-imine macrocyclic complexes: [AgL](ClO4) (1), [ZnL](ClO4)2·2H2O (2),[ZnL](NO3)2 (3), [CdL(H2O)2](ClO4)2 (4) and [CdL(NO3)(CH3OH)](NO3) (5) (L=macrocyclic ligand). All compounds have beencharacterised by microanalysis, IR, conductivity measurements, MS-FAB and 1H NMR spectroscopic studies. Compounds 1, 4and 5 were also studied by single-crystal X-ray diffraction. © 2001 Elsevier Science B.V. All rights reserved.

Keywords: Crystal structures; Template synthesis; Macrocyclic ligand complexes; Metal complexes

1. Introduction

The capability of metal ions to promote the templatesynthesis of macrocyclic ligands has been studied exten-sively and depends on several factors related to theligand characteristics, as well as on the nature of themetal ion [1].

We are interested in the metal-templated synthesis ofdi-imine macrocyclic ligands derived from 2,6-di-formylpyridine. The cyclocondensation of 2,6-di-formylpyridine and 1,5-bis(2-aminophenoxy)-3-oxo-pentane in the presence of lead(II) [2] or Ln(III) [3] ionshas been found to yield the corresponding Schiff basemacrocyclic complexes of L1. Transition and post-tran-sition metal ions were not effective as templates in thesynthesis of this ligand. When the donor atom sequenceof the precursor diamine was modified by replacing the

central oxygen atom of the ether linker with a sec-ondary amino-group we saw that zinc(II) and cadmiu-m(II) were effective in the synthesis of the 18-memberedN4O2 oxaaza-Schiff base macrocyclic ligand L2 [4].

Manganese(II) has been shown to be an effectivetemplate agent in the cyclocondensation of 2,6-di-formylpyridine and 1,4-bis(2-aminophenoxy)butane toproduce the 17-membered N3O2-oxaazadiimine macro-cyclic ligand L as its manganese(II) complex [5]. Thecorresponding reduced oxaazamacrocyclic ligand Lr, isreadily obtained by an in situ reduction of the man-ganese(II) complex with sodium tetrahydroborate andforms stable complexes with both transition and post-transition metal ions.

* Corresponding author. Fax: +34-81-597525.E-mail address: qibastid@usc.es (R. Bastida).

0020-1693/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.

PII: S 0 0 20 -1693 (01 )00322 -X

L. Valencia et al. / Inorganica Chimica Acta 317 (2001) 45–5246

As part of our studies on coordination chemistry ofoxaaza-Schiff base macrocyclic ligands, we have investi-gated the opportunity for different metals, silver(I),zinc(II) and cadmium(II) as nitrates or perchlorates, toact as templating agents in the synthesis of L. Thesyntheses of the corresponding metal complexes and theX-ray crystal structures of [AgL](ClO4) (1),[CdL(H2O)2](ClO4)2 (4), [CdL(NO3)(CH3OH)](NO3) (5)are reported herein.

2. Experimental

2.1. Synthetic procedures

2,6-Diformylpyridine was prepared according to theliterature method [6,7]. The diamine 1,4-bis(2-aminophenoxy)butane was prepared by reduction ofthe corresponding dinitro precursor using a proceduresimilar to that described previously [8,9]. Metal nitratesand perchlorates were commercial products from Alfaand Aldrich laboratories and used without furtherpurification. Solvents used were of reagent grade andpurified by the usual methods. Caution: perchlorate saltsare potentially explosi�e.

2.2. Preparation of the complexes

The appropriate metal salt (1 mmol), MX or MX2

(M=Ag, Zn and Cd, and X=NO3− or ClO4

−) and2,6-diformylpyridine (1 mmol), was dissolved andrefluxed in acetonitrile (50 ml) for 30 min. After that, asolution of 1,4-bis(2-aminophenoxy)butane (1 mmol) inacetonitrile (30 ml) was added dropwise. The mixturewas refluxed for 3 h. Then, the solution was partiallyconcentrated under vacuum to give a solid. In somecases the precipitation was aided by addition of somediethyl ether. The products were filtered off, washedwith a little cold acetonitrile and then diethyl ether andfinally air-dried.

2.2.1. [AgL](ClO4) (1)Anal. Found: C, 47.4, H, 3.8; N, 7.4. Calc. for

C23H21AgClN3O6: C, 47.7; H, 3.6; N, 7.3%. Yield: 70%.IR (KBr, cm−1): 1616m [�(C�N)], 1581s, 1491s, 1449m[�(C�C) and �(C�N)py], 1094, 620, [�(ClO4

−)]. MS(FAB, m/z): 480 [AgL]+. �M/�−1 cm2 mol−1(inCH3CN): 146 (1:1). Crystals suitable for X-ray studieswere obtained by concentration of an acetonitrile solu-tion of this complex at room temperature.

2.2.2. [ZnL](ClO4)2 ·2H2O (2)Anal. Found: C, 41.4, H, 3.8; N, 7.0. Calc. for

C23H25Cl2N3O12Zn: C, 41.1; H, 3.7; N, 6.3%. Yield:54%. IR (KBr, cm−1): 1623m [�(C�N)], 1588s, 1495s,1453m [�(C�C) and �(C�N)py], 1123, 623, [�(ClO4

−)].MS (FAB, m/z): 534 [ZnL][ClO4]+, 435 [ZnL]+. �M/�−1 cm2 mol−1(in CH3CN): 256 (2:1).

2.2.3. [ZnL](NO3)2 (3)Anal. Found: C, 49.5, H, 4.6; N, 12.1. Calc. for

C23H21N5O8Zn: C, 49.2; H, 3.8; N, 12.5%. Yield: 40%.IR (KBr, cm−1): 1620m [�(C�N)], 1592s, 1493s,[�(C�C) and �(C�N)py], 746, 812, 1037, 1286, 1385,[�(NO3

−)]. MS (FAB, m/z): 868 [Zn(L)2(NO3)]+, 806[Zn(L)2]+.

2.2.4. [CdL(H2O)2](ClO4)2 (4)Anal. Found: C, 38.7, H, 3.8; N, 5.6. Calc. for

C23H25CdCl2N3O12: C, 38.4; H, 3.5; N, 5.8%. Yield:56%. IR (KBr, cm−1): 1618m [�(C�N)], 1588s, 1495s,1455m [�(C�C) and �(C�N)py], 1119, 1100, 620,[�(ClO4

−)]. MS (FAB, m/z): 584 [CdL][ClO4]+, 485[CdL]+. �M/�−1 cm2 mol−1 (in CH3CN): 302 (2:1).Recrystallisation from acetonitrile gave crystals suitablefor X-ray diffraction studies.

2.2.5. [CdL(NO3)(CH3OH)](NO3) (5)Anal. Found: C, 45.4, H, 3.8; N, 11.3%. Calc. for

C24H25CdN5O9: C, 45.4; H, 3.5; N, 11.5%. Yield: 62%.IR (KBr, cm−1): 1615m [�(C�N)], 1588s, 1495s,[�(C�C) and �(C�N)py], 743, 809, 1027, 1295, 1384,1444 [�(NO3

−)]. MS (FAB, m/z): 547 [CdL(NO3)]+.�M/�−1 cm2 mol−1 (in CH3CN): 136 (1:1). Crystalssuitable for X-ray diffraction were obtained by recrys-tallisation of the complex from a methanol–acetonitrilemixture.

2.3. Physical measurements

Elemental analyses were performed in a Carlo-ErbaEA microanalyser. Infrared spectra were recorded asKBr discs on a Bruker IFS-66V spectrophotometer.FAB mass spectra were recorded using a Kratos-MS-50T spectrometer connected to a DS90 data systemusing 3-nitrobenzyl alcohol as the matrix. 1H NMRspectra were recorded on a Bruker AMX 300 MHz

L. Valencia et al. / Inorganica Chimica Acta 317 (2001) 45–52 47

instrument with TMS as the internal standard.Conductometric measurements were carried out in10−3 mol dm−3 acetonitrile solutions at 20°C using aWTW LF3 conductivimeter.

2.4. Crystal structure data and determination

Crystal data and experimental conditions are listed inTable 1. A yellow block of 1, a yellow needle of 4 anda yellow block of 5 were mounted on glass fibres andused for data collection. Measurements were made on aSiemens P4 four-circle diffractometer for [AgL](ClO4)(1) and on a Siemens SMART CCD area diffractome-ter for [CdL(H2O)2](ClO4)2 (4) and [CdL(NO3)(CH3-OH)](NO3) (5).

The structures were solved by direct methods usingthe SHELX93 [10] for 1 and SHELX97 [11] software for 4and 5, and refined by full-matrix least-squares methodson F2. Hydrogen atoms were included in calculated

positions and refined in riding mode. An absorptioncorrection was made by analysis of ten azimuthal scans(minimum and maximum transmission coefficients0.104 and 0.949) for 1 and using the SADABS [12]program for 4 and 5 (maximum and minimum effectivetransmission factors 1.000 000 and 0.284 368 for 4 and1.000 000 and 0.782 753 for 5). ORTEP-3 [13] was usedto provide the molecular graphics.

3. Results and discussion

The Schiff-base cyclocondensation of 2,6-di-formylpyridine and 1,5-bis(2-aminophenoxy)butane inacetonitrile in the presence of the appropriate hydratedmetal salt and in 1:1:1 mole ratio gave good yields ofthe analytically pure products [AgL](ClO4) (1), [ZnL]-(ClO4)2·2H2O (2), [ZnL](NO3)2 (3), [CdL(H2O)2](ClO4)2

(4) and [CdL(NO3)(CH3OH)](NO3) (5).

Table 1Crystal data and structure refinement for [AgL](ClO4) (1), [CdL(H2O)2](ClO4)2 (4) and [CdL(NO3)(CH3OH)](NO3) (5)

541

Empirical formula C23H21AgClN3O6 C23H25CdCl2N3O12 C24H24CdN5O9

718.76Formula weight 578.75 638.88173(2)293(2)293(2)Temperature (K)0.710 73Wavelength (A� ) 0.710 73 0.710 73

monoclinictriclinic monoclinicCrystal systemP21/nP1� P21/nSpace group

Unit cell dimensions8.5282(2)10.406(4) 8.26730(10)a (A� )

10.661(5)b (A� ) 10.8570(2) 16.8028(3)18.3648(3)29.9135(7)c (A� ) 11.562(6)

90.90� (°)93.6880(8)107.65(3) 95.2680(10)� (°)

113.90(2)� (°)1103.3(9)Volume (A� 3) 2763.98(10) 2540.35(7)1Z 4 4

1.6701.727Calculated density (Mg m−3) 1.7421.082Absorption coefficient (mm−1) 1.051 0.923584F(000) 1448 12920.75×0.43×0.32Crystal size (mm3) 0.65×0.20×0.15 0.45×0.40×0.30

1.36 to 28.29Theta range for data collection 1.65 to 28.311.87 to 25.12(°)

−1�h�12, −12�k�11,Index ranges −8�h�11, −21�k�22,−8�h�11, −14�k�11,−13�l�13 −21�l�24−38�l�394582/3893, 0.0509Reflections collected/unique, Rint 14 867/6771, 0.0944 17 406/6262, 0.0272

28.29°, 93.8%Completeness to 2� 28.31°, 96.0%Full-matrix least-squares on F2Refinement method Full-matrix least-squares on F2 Full-matrix least-squares on F2

3893/0/308Data/restraints/parameters 6771/0/370 6262/0/3521.044Goodness-of-fit on F2 0.967 1.053

Final R indices [I�2�(I)]0.0444R1 0.0801 0.0317

wR2 0.1175 0.1784 0.0872R Indices (all data)

0.0386R1 0.15670.05310.1250 0.2129wR2 0.09100.013(2)Extinction coefficient0.801 and −1.010 1.029 and −1.7361.621 and −2.595Largest diff. peak and hole

(e A� −3)

L. Valencia et al. / Inorganica Chimica Acta 317 (2001) 45–5248

Table 21H NMR data (�, ppm) in CD3CN for [AgL](ClO4) (1), [ZnL](ClO4)2·2H2O (2) and [CdL(H2O)2](ClO4)2 (4) and in CD3OD for[CdL(NO3)(CH3OH)](NO3) (5) a

2 4 51

8.62 (t, 1H)Ha 8.90 (t, 1H)8.30 (t, 1H) 8.47 (t, 1H)Hb 8.02 (d, 2H) 8.36 (d, 2H) 8.34 (d, 2H) 8.24 (d, 2H)

8.98 (s, 2H)Hc 9.34 (s, 2H) 9.40 (s, 2H) 9.49 (s, 2H)7.98–7.26 (m, 8H) 8.01–7.30 (m, 8H)7.66–7.11 (m, 8H) 7.94–7.12 (m, 8H)Har

4.21 (d, 4H)Hd 4.61 (d, 4H) 4.54 (d, 4H) 4.34 (d, 4H)He 2.26 (q, 4H)2.28 (q, 4H) 2.48 (q, 4H) 2.31 (q, 4H)

a s, singlet; d, doublet; t, triplet; q, quintuplet; m, multiplet.

All of the complexes exhibit a �(C�N) vibration inthe range 1623–1615 cm−1, and also bands at approxi-mately 1600 and 1450 cm−1 associated with �(C�N)py

and �(C�C) vibrations from the pyridine and phenylrings [14]. Individual spectra are consistent with thepresence of water, or with other solvent molecules whenindicated to be present from the microanalytical data.For the perchlorate complexes, absorptions attributableto ionic perchlorate were found at approximately 1100and 625 cm−1 [15]. The lack of splitting of these bandssuggests that the perchlorate anions are not coordi-nated. This result is supported by the conductancemeasurements of the complexes in acetonitrile andconfirmed by the solution of the crystal structures ofcomplexes 1 and 4. The presence of several bands in theregion associated with nitrate vibrations clearly iden-tifies these species as containing coordinated nitrategroups [16]. In the spectra of all nitrate-containingcomplexes the absorption bands appear in the regions1430–1455, 1290–1328 and 1020–1040 cm−1, whichare assignable to the �(N�O) (�1), �asym(NO2) (�5) and�sym(NO2) (�2) vibrations respectively [17].

The molar conductance values for the perchloratecomplexes, measured in acetonitrile at 25°C are in therange characteristic of 1:1 electrolytes for 1 and 2:1electrolytes for 2 and 4 [18]. For 5, measured under thesame conditions, the value is in the range characteristicfor a 1:1 electrolyte and indicating the higher coordi-nating capability of the nitrate anion. It was not possi-ble to determine the conductivity value for 3 due to thelow solubility of the compound.

Positive-ion FAB mass spectrometry provided fur-ther evidence for cyclocondensation and the formationof di-imine complexes. The spectra show, in most cases,

peaks assignable to [MLX]+ and [ML]+ (M=Ag(I),Zn(II), Cd(II), X=NO3

−, ClO4−), and all assigned

peaks show the isotopic contribution of the metals. Inthe complex [ZnL(NO3)2] two peaks at 868 a.m.u. and806 a.m.u., corresponding to [Zn(L)2(NO3)]+ and[Zn(L2�H)]+ respectively, are present, suggesting thepresence of the tetraiminic macrocycle — oligomerisa-tion within the matrix is also possible under the condi-tions of the FAB experiment.

The 1H NMR spectra (Table 2) were taken inCD3CN for [AgL](ClO4) (1), [ZnL](ClO4)2·2H2O, (2)and [CdL(H2O)2](ClO4)2 (4) and in CD3OD for[CdL(NO3)(CH3OH)](NO3) (5) and show the presenceof the di-iminic ligand for all the complexes, showingthat the integrity of the complex is retained in solution.The signal corresponding to the iminic proton, Hc,appears in the range (�, ppm) 9.49–8.98. In the Cdcomplexes this signal appears with satellite signals dueto the coupling with 113Cd, 3J(113Cd–1H) 42 Hz for 4and 41 Hz for 5, values that correspond to those re-ported in the literature [19]. Complex 3 could not bestudied by NMR due to its low solubility in deuteratedsolvents.

3.1. Crystal structure of [AgL](ClO4) (1)

The structure of the complex with atom labelling isillustrated in Fig. 1. Selected bond lengths and angles atthe metal, with standard deviations in parentheses, aregiven in the caption to the figure. Atomic coordinatesand equivalent isotropic displacements are given inTable 3. The silver atom is in a distorted pentagonalplanar endomacrocyclic environment coordinated by alldonor atoms of the N3O2-macrocyclic ligand. The

L. Valencia et al. / Inorganica Chimica Acta 317 (2001) 45–52 49

Ag�N bond distances observed are different: the short-est corresponds to the Ag� Npyridinyl bond, 2.325(4) A� ,and the other two, 2.484(4) and 2.508(4) A� , to theAg�Niminic bonds. The Ag�Oether bond distances of2.659(4) and 2.685(4) A� are greater than the covalentbond value for Ag�O, but shorter than the sum of thevan der Waals radii (3.24 A� ). The sum of the anglessubtended by the donor atoms at Ag is 359.87° and theplane containing N(1), N(2), N(3), O(1) and O(2) hasan r.m.s. of 0.1519 with the metal atom being 0.1908 A�out of this plane. The shortness of the Ag�N bonds,relative to the Ag�O bonds, reflects the greater affinityof the metal for the softer iminic N environment, andthe bond angles at the metal reflect the greater rigidityof the pyridinyl–diimine–phenylic fragment of themolecule, in which all of the chelating rings are five-membered relative to the flexibility of the aliphaticspacer, which provides a seven-membered chelate ring.Within the macrocyclic ligand the two planar phenylrings (r.m.s. 0.0040 and 0.0053) are tilted at an angle of12° to each other, and the dihedral angles between thepyridine ring and the phenyl rings are 4° and 12°respectively.

3.2. Crystal structure of [CdL(H2O)2](ClO4)2 (4)

The structure of the cation from 4, [CdL(H2O)2]2+, isillustrated in Fig. 2. Selected bond lengths and angles,with standard deviations in parentheses, are given incaption to the figure. Atomic coordinates and equiva-

Table 3Atomic coordinates (×104) and equivalent isotropic displacements(A� ×103) for [AgL](ClO4) (1)

y z Ueqx

4515(1)7562(1) 64(1)120(1)Ag(1)59(1)Cl(2) 3551(1) 6774(1) 1565(1)

−970(4) 5613(4)N(1) 5589(3) 50(1)N(2) 972(4) 8274(3) 6626(3) 48(1)

49(1)5089(3)10 126(3)N(3) 1746(4)5253(3)O(1) 66(1)3157(3)−2247(4)

O(2) 9018(3)638(4) 2727(3) 65(1)−539(5) 6744(4) 52(1)C(1) 5935(4)

612(4)C(2) 51(1)7341(4) 7365(4)C(3) 60(1)8628(4)7650(5)1291(5)

65(1)9137(4)8982(5)C(4) 2394(5)9950(5)C(5) 61(1)8379(4)2768(5)

C(6) 9556(4)2021(4) 7111(4) 50(1)6237(4)2407(5) 52(1)10 521(4)C(7)

11 024(4) 4233(4) 49(1)C(8) 2118(4)4549(5)3010(5) 59(1)12 452(5)C(9)

C(10) 67(1)3659(5)13 261(5)3307(6)2447(5)12 668(6) 72(1)2719(6)C(11)

C(12) 68(1)1849(6) 11 253(6) 2108(S)1529(5)C(13) 55(1)10 425(5) 2997(4)

C(14) 73(1)1491(4)8333(6)161(6)69(1)1435(5)6828(6)−821(6)C(15)

6588(6)C(16) 69(1)1550(5)−2308(5)C(17) 5198(5)−3074(5) 1906(4) 68(1)

3700(4)−2717(5) 56(1)4098(5)C(18)2790(5) 3047(5) 65(1)C(19) −3780(5)1669(5) 3659(6) 71(1)C(20) −4202(5)

69(1)4922(6)1832(5)C(21) −3578(5)3119(5) 5571(5) 60(1)C(22) −2513(5)

−2071(4) 4262(4)C(23) 4978(4) 52(1)93(1)2017(4)8099(4)O(3) 3713(5)

2013(4) 5845(5)O(4) 1119(4) 103(1)4329(5) 2545(4) 101(1)O(5) 6291(5)

95(1)608(4)4163(5) 6927(5)O(6)

Fig. 1. The molecular structure of [AgL](ClO4) (1) together withselected bond lengths (A� ) and angles (°). Bond lengths: Ag(1)�N(1),2.484(4); Ag(1)�N(2), 2.325(4); Ag(1)�N(3), 2.508(4); Ag(1)�O(1),2.685(4); Ag(1)�O(2), 2.659(4). Bond angles: N(2)�Ag(1)�N(1),68.55(12); N(2)�Ag(1)�N(3), 68.35(12); O(1)�Ag(1)�N(2), 126.50(12);O(2)�Ag(1)�N(1), 161.05(12); O(2)�Ag(1)�N(3), 61.80(12); N(1)�Ag(1)�N(3), 136.72(12); O(1)�Ag(1)�N(1), 61.95(12); O(1)�Ag(1)�N(3), 155.50(12); O(2)�Ag(1)�N(2), 130.19(12); O(2)�Ag(1)�O(1),99.22(12). Sum of the angles subtended by the donor atoms at Ag:O(1)�Ag(1)�N(1), 61.95°; N(1)�Ag(1)�N(2), 68.55°; N(2)�Ag(1)�N(3), 68.35°; N(3)�Ag(1)�O(2), 61.80°; O(2)�Ag(1)�O(1), 99.22°.

lent isotropic displacements are given in Table 4. Themetal ion is in a distorted pentagonal bipyramidalendomacrocyclic environment involving the full donoratom set of the N3O2-macrocyclic ligand and the oxy-gen atoms of two water molecules of solvation. The twoO atoms from the water molecules occupy the axialpositions of the bipyramid with a trans-axial angle[O(2W)�Cd�O(1W)] of 160.3(2)°. The sum of the anglessubtended by the donor atoms at Cd is 360.67° and theplane containing N(1), N(2), N(3), O(1) and O(2) hasan r.m.s. of 0.1179 and the metal atom is close toco-planarity, being only 0.025 A� out of this plane. Inthe macrocyclic ligand the two planar phenyl rings(r.m.s. 0.0119 and 0.0184) are tilted at an angle of 10°to each other, and the dihedral angles between thepyridine ring and the phenyl rings are 10.78° and 3.29°respectively.

The three Cd�N bond distances varied from2.281(6) A� for the Cd�Npyridinyl bond to 2.463(6) and2.421(6) A� for the Cd�Nimine; the Cd�O bond distancesare also varied, being 2.239(5) and 2.253(5) A� for the

L. Valencia et al. / Inorganica Chimica Acta 317 (2001) 45–5250

Cd�Owater bonds and 2.646(5) and 2.673(5) A� for theCd�Oether bonds. The bond distances observed betweenthe Cd and the macrocyclic ring donors again reflectthe hard and soft character of the donors. The distancesbetween the Cd atom and the Oether atoms are longerthan the covalent bond value for Cd�O, but shorterthan the sum of the van der Waals radii (3.10 A� ) [20].The Oether interactions are also longer than the Owater

interactions, reflecting the stronger donor capability ofthe water molecules. The perchlorate anions are non-coordinating, in contrast to the nitrate anions in 5.

3.3. Crystal structure of [CdL(NO3)(CH3OH)](NO3) (5)

The molecular structure of the cation from the com-plex [CdL(NO3)(CH3OH)]+ is given in Fig. 3 withselected bond lengths and angles, with standard devia-tions in parentheses, presented in the caption to thefigure. Atomic coordinates and equivalent isotropic dis-placements are given in Table 5. The data for the[CdL(NO3)(CH3OH)](NO3) complex were collected at173 K because the crystals are unstable at higher tem-peratures due to loss of solvent. The X-ray structureconfirms that 5 is a mononuclear endomacrocyclic com-plex. The metal atom is seven-coordinated with a dis-

Table 4Atomic coordinates (×104) and equivalent isotropic displacements(A� ×103) for [CdL(H2O)2](ClO4)2 (4)

x Ueqzy

3804(1) 1412(1) 1274(1)Cd(1) 46(1)824(2) 56(1)O(1) 887(5)1076(6)

4260(6) −799(5) 1631(2) 54(1)O(2)47(2)N(1) 3157(6)5295(7) 1291(2)

2393(7) 3108(6) 909(2) 45(1)N(2)N(3) 45(1)1685(2)6355(7) 1039(6)

6764(9) 3126(8) 1492(3) 54(2)C(1)7681(12) 4184(9) 1524(3)C(2) 73(3)

77(3)C(3) 7129(13) 1327(3)5244(9)5648(11) 5250(8) 1104(3) 64(2)C(4)4768(10) 4189(7) 1105(2) 52(2)C(5)

53(2)886(3)4094(8)C(6) 3179(9)49(2)C(7) 3028(8)819(9) 708(2)

C(8) 65(2)562(3)−56(11) 4036(9)−1563(11) 3900(9) 362(3) 72(3)C(9)

70(2)C(10) 2752(10)−2157(10) 321(3)473(3) 65(2)C(11) 1724(9)−1363(9)

182(9) 1859(8) 668(2) 51(2)C(12)67(2)C(13) −351(8)535(10) 714(3)61(2)C(14) −1244(8)1653(10) 913(3)68(2)1420(3)−1270(8)C(15) 1592(10)65(2)C(16) 3114(10) −1768(8) 1652(3)

C(17) 52(2)1842(2)5714(9) −1062(8)6119(11) −2221(9) 2011(3) 64(2)C(18)7614(11) −2423(10) 2208(3) 73(3)C(19)

75(3)2255(3)−1464(11)C(20) 8686(11)64(2)C(21) −343(9)8292(9) 2094(3)

C(22) 52(2)1873(2)6817(9) −118(8)7290(10) 1964(8) 1693(3) 56(2)C(23)

64(2)O(1W) 1628(5)2303(7) 1861(2)660(2) 63(2)O(2W) 619(6)4787(6)

1850(2) 5094(2) 2052(1) 60(1)Cl(1)55(1)Cl(2) 2219(2)3146(2) −366(1)

106(3)O(11) 5860(8)1058(10) 2339(3)107(3)1607(2)5485(8)O(12) 1442(10)

1270(11) 3878(7) 2097(3)O(13) 105(3)O(14) 5196(11) 2145(4)3466(9) 158(4)

2865(8) 1167(6) −92(2) 83(2)O(21)3939(9) 3165(7) −116(2) 94(2)O(22)

130(4)−710(3)1853(7)O(23) 4004(13)1690(9) 2716(8) −533(3)O(24) 123(3)

Fig. 2. The molecular structure of the cation from 4, [CdL(H2O)2]2+,together with selected bond distances (A� ) and angles (°). Bondlengths: Cd(1)�N(1), 2.281(6); Cd(1)�N(2), 2.421(6); Cd(1)�N(3),2.463(6); Cd(1)�O(1), 2.673(5); Cd(1)�O(2), 2.646(5); Cd(1)�O(1W),2.253(5); Cd(1)�O(2W), 2.239(5). Bond angles: O(2W)�Cd(1)�O(1W),160.3(2); O(1W)�Cd(1)�N(10), 103.8(2); O(1W)�Cd(1)�N(2),88.93(19); O(2W)�Cd(1)�N(3), 89.0(2); N(1)�Cd(1)�N(3), 69.6(2);O(2W)�Cd(1)�O(2), 85.96(19); N(1)�Cd(1)�O(2), 132.6(2); N(3)�Cd(1)�O(2), 63.07(18); O(1)�Cd(1)�O(1W), 83.95(2); O(1)�Cd(1)�N(2), 62.86(2); O(2W)�Cd(1)�N(1), 95.8(2); O(2W)�Cd(1)�N(2), 97.1(2); N(1)�Cd(1)�N(2), 68.8(2); O(1W)�Cd(1)�N(3), 98.9(2);N(2)�Cd(1)�N(3), 138.4(2); O(1W)�Cd(1)�O(2), 81.70(18); N(2)�Cd(1)�O(2), 158.11(18); O(1)�Cd(1)�O(2W), 82.26(2); O(1)�Cd(1)�N(1), 130.89(2). Sum of the angles subtended by the donor atoms atCd: O(2)�Cd(1)�N(3), 63.07; N(3)�Cd(1)�N(1), 69.6; N(1)�Cd(1)�N(2), 68.8; N(2)�Cd(1)�O(1), 62.86; O(1)�Cd�O(2), 96.34.

torted pentagonal bipyramidal geometry arising fromcoordination by all donor atoms of the N3O2-macro-cyclic ligand, the O atom of a methanol of solvationand an O atom, O(8), from a monodentate nitrateanion — the methanol and nitrate groups are sitedtrans to each other.

The equatorial interactions between the macrocyclicligand and the Cd compare favourably with those notedin 4. The three Cd�N bond distances vary from2.2955(19) A� for the Cd�Npyridinyl bond to 2.448(2) and2.407(2) A� for the Cd�Nimine, and the Cd�Oether bonddistances are 2.6454(16) and 2.6617(16) A� . As in 4, theaxial distances are shorter: the Cd�Omethanol distance is2.2936(17) A� and the Cd�Onitrate distance [Cd(1)�O(8)]is 2.2671(18) A� . A second oxygen atom, (O7), of the

L. Valencia et al. / Inorganica Chimica Acta 317 (2001) 45–52 51

nitrate group sits at 2.7233 A� from the metal. Thisdistance is considerably shorter than the sum of the vander Waals radii, and so the nitrate anion could beviewed as a weak asymmetric chelating anion; thiswould give a distorted eight coordination at the metalcentre. The second nitrate anion is not coordinated tothe metal. The sum of the angles subtended by thedonor atoms at Cd is 361.91° and the plane containingN(1), N(2), N(3), O(1) and O(2) has an r.m.s. of 0.2123and the metal atom is displaced from this towards themonodentate nitrate oxygen atom, O(8), by 0.1127 A� .In the macrocyclic ligand the dihedral angles betweenthe planar pyridine ring and the planar phenyl ringsC(7)�C(12) and C(17)�C(22) are 7.18° and 17.85° re-spectively. The dihedral angle between the two aro-matic rings is 19.27°. The r.m.s. values of the aromaticrings are 0.0028 and 0.0106. The second nitrate anion isnot coordinated.

4. Conclusions

Mononuclear cadmium(II) zinc(II) and silver(I)macrocyclic Schiff base complexes have been prepared

Table 5Atomic coordinates (×104) and equivalent isotropic displacements(A� ×103) for [CdL(NO3)(CH3OH)](NO3) (5)

x y z Ueq

Cd(1) 5708(1) 21(1)201(1) 7813(1)N(1) 4392(2) −931(1) 8136(1) 22(1)N(2) 6343(2) −106(1) 22(1)9111(1)N(3) 3847(2) 23(1)−251(1) 6814(1)N(4) 2854(3) 2324(1) 36(1)9362(1)N(5) 8439(2) −593(1) 7243(1) 28(1)O(1) 7240(2) 1316(1) 8627(1) 26(1)O(2) 5919(2) 910(1) 29(1)6529(1)O(3) 4036(2) 1875(1) 9240(1) 37(1)O(4) 1763(3) 2466(1) 42(1)8883(1)O(5) 2773(4) 92(1)2572(2) 9988(2)O(6) 9740(3) −786(2) 57(1)7026(2)O(7) 7150(2) 37(1)−943(1) 7044(1)O(8) 8379(2) −14(1) 7695(1) 31(1)O(9) 3660(2) 1079(1) 30(1)7996(1)C(1) 3428(3) −1315(1) 7628(1) 23(1)C(2) 2692(3) −2037(1) 28(1)7782(1)C(3) 2985(3) 30(1)−2353(2) 8479(1)C(4) 4000(3) −1954(1) 28(1)9003(1)C(5) 23(1)4676(3) −1235(1) 8807(1)C(6) 5738(3) −756(1) 9324(1) 25(1)C(7) 7399(3) 368(1) 23(1)9585(1)C(8) 8030(3) 28(1)125(2) 10 282(1)C(9) 9112(3) 599(2) 10 707(1) 31(1)C(10) 9564(3) 1327(2) 32(1)10 437(1)C(11) 8950(3) 1588(2) 9751(1) 29(1)C(12) 7866(3) 1106(1) 9317(1) 23(1)C(13) 7443(3) 2137(1) 30(1)8401(1)C(14) 6792(3) 2188(1) 7609(1) 30(1)C(15) 7916(3) 1789(2) 31(1)7100(1)C(16) 7026(3) 34(1)1549(2) 6385(1)C(17) 4727(3) 736(1) 26(1)5981(1)C(18) 4602(3) 1113(2) 5301(1) 34(1)C(19) 3335(4) 914(2) 41(1)4781(2)C(20) 2204(4) 349(2) 4933(2) 45(1)C(21) 2334(3) −42(2) 5604(2) 38(1)C(22) 3609(3) 140(1) 26(1)6126(1)C(23) 3195(3) −928(1) 6909(1) 25(1)C(24) 1979(3) 872(2) 7838(2) 32(1)

Fig. 3. The molecular structure of the cation from 5,[CdL(NO3)(CH3OH)]+, together with selected bond lengths (A� ) andangles (°). Bond lengths: Cd(1)�N(1), 2.2955(19); Cd(1)�N(2),2.448(2); Cd(1)�N(3), 2.407(2); Cd(1)�O(1), 2.6454(16); Cd(1)�O(2),2.6617(16); Cd(1)�O(7), 2.7233(19); Cd(1)�O(8), 2.2671(18);Cd(1)�O(9), 2.2936(17). Bond angles: O(8)�Cd(1)�O(9), 148.72(7);O(8)�Cd(1)�N(1), 112.47(7); O(9)�Cd(1)�N(1), 96.95(6); O(8)�Cd(1)�N(3), 115.94(7); O(9)�Cd(1)�N(3), 83.43(6); N(1)�Cd(1)�N(3),69.55(7); O(8)�Cd(1)�N(2), 86.31(7); O(9)�Cd(1)�N(2), 95.06(6);N(1)�Cd(1)�N(2), 68.82(7); N(3)�Cd(1)�N(2), 137.82(7); O(8)�Cd(1)�O(1), 75.31(6); O(9)�Cd(1)�O(1), 77.48(6); N(1)�Cd(1)�O(1),130.87(6); N(3)�Cd(1)�O(1), 153.30(6); N(2)�Cd(1)�O(1), 63.27(6);O(8)�Cd(1)�O(2), 80.97(6); O(9)�Cd(1)�O(2), 87.18(6); N(1)�Cd(1)�O(2), 132.12(6); N(3)�Cd(1)�O(2), 63.58(6); N(2)�Cd(1)�O(2),158.60(6); O(1)�Cd(1)�O(2), 96.69(5); O(8)�Cd(1)�O(7), 50.37(6);O(9)�Cd(1)�O(7), 153.35(6); N(1)�Cd(1)�O(7), 77.87(6); N(3)�Cd(1)�O(7), 70.21(6); N(2)�Cd(1)�O(7), 106.95(6); O(1)�Cd(1)�O(7),125.68(5); O(2)�Cd(1)�O(7), 77.83(6). Sum of the angles sub-tended by the donor atoms at Cd: O(2)�Cd(1)�N(3), 63.58;N(3)�Cd(1)�N(1), 69.55; N(1)�Cd(1)�N(2), 68.82; N(2)�Cd(1)�O(1),63.27; O(1)�Cd�O(2), 96.69.

by the metal-templated cyclocondensation of 2,6-pyridinedicarbaldehyde and 1,4-bis(2-aminophe-noxy)butane. The crystal structures of the [AgL](ClO4),[CdL(H2O)2](ClO4)2 and [CdL(NO3)(CH3OH)](NO3)compounds show that the nitrate anions are metalcoordinated whereas the perchlorate anions are not,clearly indicating their relative coordination strengths.

Acknowledgements

We thank the Xunta de Galicia (XUGA20903B96and PGIDT99PXI20902B), Spain for financial supportand the EPSRC for funds towards the purchase of adiffractometer.

L. Valencia et al. / Inorganica Chimica Acta 317 (2001) 45–5252

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