Synthesis and crystal structure of two new heteropolynuclear [NiIICdIICdIINiII] and [NiIICdIINiII] Schiff base complexes involving bridging chlorine and oxygen functions

Polyhedron 30 (2011) 2678–2683

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Synthesis and crystal structure of two new heteropolynuclear [NiIICdIICdIINiII] and [NiIICdIINiII] Schiff base complexes involving bridging chlorine and oxygen functions Debasis Bandyopadhyay a,⇑, Debasis Karmakar a, Guillaume Pilet b, Michel Fleck c a

Department of Chemistry, Bankura Christian College, Bankura, West Bengal, India Laboratoire des Multi-matériaux et Interfaces, Groupe de Cristallographie et Ingénierie Moléculaire, UMR 5615, CNRS – Université Claude Bernard Lyon 1, 2 Avenue Grignard, 69622 Villeurbanne cedex, France c Institute of Mineralogy and Crystallography Geozentrum, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria b

a r t i c l e

i n f o

Article history: Received 10 June 2011 Accepted 15 July 2011 Available online 5 August 2011 Keywords: Nickel(II) Cadmium(II) Heteropolynuclear complexes Schiff base Crystal structure Chloro and phenoxo bridges

a b s t r a c t Two new heteropolynuclear Schiff base complexes, [Ni2Cd2L2Cl2(l-Cl)2] (1) and [Ni2CdL0 2Cl(H2O)]ClO4H2O (2) where L = [N,N0 -bis(2-hydroxyacetophenylidene)]propane-1,2-diamine and L0 = [N,N0 bis(2-hydroxypropiophenylidene)]propane-1,2-diamine, have been synthesized by refluxing equimolar amounts of nickel perchlorate, cadmium chloride and the respective tetradentate Schiff base ligand, H2L or H2L0 in methanol medium. The complexes have been characterized by microanalytical, spectroscopic, single crystal X-ray diffraction and other physicochemical studies. Structural studies on 1 reveal the presence of a bis(heterodinuclear) [NiIICdII]2 unit in which the two central cadmium ions are doubly chloro-bridged with each other and each of them is connected to a nickel(II) center through two phenolate oxygen bridges. In contrast, complex 2 contains a heterotrinuclear [NiIICdIINiII] unit in which the central cadmium ion is connected to two nickel(II) centers through two doubly bridging phenolate oxygen atoms. The Cd(II) ions in 1 and 2 adopt distorted, square pyramidal (CdO2Cl3) and octahedral (CdO5Cl) geometries respectively. On the other hand, the Ni(II) ions in both 1 and 2 assume the same coordination geometry, i.e. a distorted square planar (NiO2N2) arrangement. Intermolecular C–H  Cl or O–H  Cl and O–H  O hydrogen bonding interactions are operative in the complexes to build up 2D supramolecular structures in their solid states. Ó 2011 Elsevier Ltd. All rights reserved.

1. Introduction Transition metal complexes containing Schiff base ligands have been of specific interest for many years. Studies on such complexes of nickel(II) or cadmium(II) have received overwhelming attention due to their extensive use in the design and preparation of molecule based materials [1–6]. The structural diversity leading to supramolecular architecture through various non-covalent intermolecular interactions in the solid state gives further impetus to the extensive study of these complexes [7,8]. Innumerous mononuclear and homopolynuclear Schiff base complexes of nickel(II) and cadmium(II) are well known, but heteropolynuclear complexes containing both nickel(II) and cadmium(II) centers have not received adequate attention. Although a limited number of such complexes have been reported very recently [9–11], reports on the synthesis of heterometallic Ni(II)–Cd(II) complexes involving heterobridging chlorine and/or phenolate oxygen functions are lacking. ⇑ Corresponding author. Tel./fax: +91 3242 250924. E-mail address: [email protected] (D. Bandyopadhyay). 0277-5387/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.poly.2011.07.026

Ligand dependent assembly of different metal ions, polydentate Schiff base ligands and bridging anions has always been a good choice for preparing bridged heteronuclear complexes [9–12]. We describe here the syntheses of two new heterometallic Schiff base complexes, viz. tetranuclear [Ni2Cd2L2Cl2(l-Cl)2] (1) where L = [N,N0 -bis(2-hydroxyacetophenylidene)]propane-1,2-diamine and trinuclear [Ni2CdL0 2Cl(H2O)]ClO4H2O (2) where L0 = [N,N0 -bis (2-hydroxypropiophenylidene)]propane-1,2-diamine, without using any extra bridging anions. The tetradentate Schiff base ligands were prepared by the condensation of 1,2-diaminopropane with 2-hydroxyacetophenone for H2L and with 2-hydroxypropiophenone for H2L0 . The complexes have been characterized by microanalytical, spectroscopic, thermogravimetric and single crystal X-ray diffraction studies. Structural studies indicate the presence of two doubly chloro-bridged square pyramidal cadmium(II) centers in 1 and a single octahedral cadmium(II) center in 2. The cadmium(II) complex unit is linked to one square planar [NiL] moiety for each cadmium center in 1 and to two similar [NiL0 ] moieties in 2 through one and two doubly bridging phenolate oxygen atoms, respectively. These molecular units of 1 and 2 are further linked by weak intermolecular H-bonding in their solid states.

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2927(m), 2850(w), 1599(s), 1585(s), 1439(m), 1321(s), 1245(m), 1145(w), 864(w), 755(m). UV–Vis (k, nm): 388, 340, 318, 289. KM (MeOH, X1 cm2 mol1): 6. Diamagnetic.

2. Experimental 2.1. Physical measurements Elemental analyses for carbon, hydrogen and nitrogen were carried out using a Perkin-Elmer 2400-II elemental analyzer. The nickel content was determined gravimetrically by converting it to its dimethylglyoximate complex. The infrared spectra were recorded on a Perkin-Elmer Spectrum 65 FTIR spectrophotometer with KBr discs (4000–400 cm1). The electronic spectra were obtained on a Systronics 2202 spectrophotometer using methanol as the solvent at 104 M concentration. Room temperature solid phase magnetic susceptibilities were measured at 298 K with a PAR 155 vibrating sample magnetometer with Hg[Co(NCS)4] as the calibrant. Molar conductances of the complexes in dry methanol were measured using a direct reading conductivity meter of Systronics (Type 304). Thermogravimetric analyses were carried out using a Netzsch STA409PC instrument from 30 to 700 °C in an atmosphere of dinitrogen at the heating rate of 10 °C min1. 2.2. Materials Commercially available reagent grade 2-hydroxyacetophenone, 2-hydroxypropiophenone, 1,2-diaminopropane, nickel(II) perchlorate hexahydrate, cadmium chloride monohydrate and methanol were used without further purification. The tetradentate Schiff base ligands H2L and H2L0 were obtained by the condensation of 1,2-diaminopropane with the respective carbonyl compounds using similar methods as described earlier [13].

OH N

HO N

R CH3

R

H2L (R = CH3); H2L (R = C2H5)

2.3.2. Synthesis of [Ni2CdL0 2Cl(H2O)]ClO4H2O (2) The synthetic route described for 1 in Section 2.3.1 above was followed for the preparation of 2, except that a 10 mL methanolic solution of H2L0 (0.17 g, 0.5 mmol) was used instead of H2L. Red crystals of 2 appeared after a week in this case. Yield: 0.15 g, 56% (based on Ni). Anal. Calc. for C42H52CdCl2N4Ni2O10: C, 46.99; H, 4.88; N, 5.22; Ni, 10.93. Found: C, 47.03; H, 4.86; N, 5.21; Ni, 10.82%. FTIR (KBr, cm1): 3460(s), 2974(m), 2934(m), 1599(s), 1585(s), 1439(s), 1321(s), 1255(m), 1095(s), 855(w), 755(m). UV– Vis (k, nm): 398, 344, 315, 304. KM (MeOH, X1 cm2 mol1): 120. Diamagnetic. 2.4. Crystal structure determination and refinement Suitable single crystals of 1 and 2 with dimensions of 0.09  0.06  0.06 and 0.08  0.06  0.04 mm3, respectively were mounted on a Nonius Kappa diffractometer, equipped with a CCD area detector and graphite monochromated Mo Ka radiation (k = 0.71073 Å). The reflection data were collected and processed using the Bruker-Nonius program suites COLLECT, DENZO-SMN and related analysis software [14–16]. An absorption correction based on the crystal faces was applied to the data sets (analytical) of 1. The structures were solved by direct methods and subsequent Fourier and difference Fourier syntheses, followed by full-matrix least-square refinements on F, using the programs SIR97 [17] and 2 CRYSTALS [18] (for 1) and on F using the program SHELX [19] (for 2). All atomic displacements parameters for non-hydrogen atoms have been refined with anisotropic terms. The hydrogen atoms were theoretically located on the basis of the conformation of the supporting atom and refined keeping restrains (riding mode). It is to be noted that the hydrogen atoms of the water molecule (involving O2W) in compound 2 could not be located in the Table 1 Crystallographic data for 1 and 2.

Caution! Perchlorate salts, especially in presence of organic ligands, are potentially explosive. Therefore, only a small amount of the materials should be used at a time and handled with proper care. However, no problems were encountered during our studies, including the thermogravimetric analyses of the compounds within the experimental range of temperature under an inert atmosphere. 2.3. Synthesis of the complexes 2.3.1. Synthesis of [Ni2Cd2L2Cl2(l-Cl)2] (1) A solution of nickel(II) perchlorate hexahydrate (0.18 g, 0.5 mmol) in methanol (10 mL) was added slowly with constant stirring to a methanolic solution (10 mL) of the Schiff base ligand, H2L (0.16 g, 0.5 mmol). Cadmium chloride monohydrate (0.1 g, 0.5 mmol) dissolved in a few drops of water followed by methanol (10 mL), was added dropwise to the mixture. The resulting red solution was refluxed for an hour and then left for slow evaporation at room temperature in a beaker open to the atmosphere. After about 5 days, bright red crystals of compound 1 appeared. The crystals were collected by filtration, washed with a little methanol and finally dried. Yield: 0.12 g, 44% (based on Ni). Anal. Calc. for C38H40Cd2Cl4N4Ni2O4: C, 41.46; H, 3.66; N, 5.09; Ni, 10.66. Found: C, 41.53; H, 3.72; N, 5.12; Ni, 10.52%. FTIR (KBr, cm1): 2970(m),

a

Parameters

1

2

Formula Formula weight (g mol1) Crystal system Space group a (Å) b (Å) c (Å) a (°) b (°) c (°) V (Å3) Z Dcalc (g cm3) l (mm1) F (0 0 0) Crystal size (mm3) hkl range T (K) k (Mo Ka) (Å) h Range for data collection (°) Reflections collected No. of unique reflections Rint No. of reflections used No. of parameters refined Ra wRa S Dqmax, Dqmin (e Å3)

C38H40Cd2Cl4N4Ni2O4 1100.8 triclinic  P1

C42H52CdCl2N4Ni2O10 1073.58 triclinic  P1

10.0528(7) 10.1120(7) 12.5541(8) 113.484(2) 91.629(3) 117.404(3) 1003.3(1) 1 1.822 2.281 548 0.09  0.06  0.06 ±15, ±15, ±19 296(2) 0.71073 2.5–29.4 13 093 6539 0.026 4394 244 0.0377 0.0486 1.00 1.31, 0.70

13.0753(8) 13.5555(7) 14.9097(9) 69.789(3) 68.401(3) 73.245(2) 2266.1(2) 2 1.570 1.465 1096 0.08  0.06  0.04 ±18, ±19, ±20 296(2) 0.71073 5.0–24.4 24 196 13 099 0.031 8402 558 0.0920 0.1104 1.025 0.72, 0.48

I > 3.0r(I) > 1 for 1; I > 2.0r(I) > 2 for 2.

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100

(1) (2)

90

% Weight Loss

80 70 60 50 40 30 100

200

300

400

500

600

700

o

Temperature ( C)

3.2. FTIR and electronic spectra The infrared spectra of compounds 1 and 2 have some common features as expected from their structural similarities. Both of them exhibit strong absorption bands at 1585 and 1599 cm1 corresponding to the stretching vibrations of the C@N bond [mCN] of the Schiff base ligands. A broad and strong band at around 3460 cm1 indicates the presence of H2O molecules in compound 2. The asymmetric single and sharp band expected for ClO4 is also observed at 1095 cm1 in compound 2. All other characteristic vibrations of the metal-bound ligands are located in the range 600–1600 cm1. Thus, the IR spectra of the compounds agree well [20] with the respective structural features of 1 and 2. The electronic spectra of compounds 1 and 2 in methanolic solutions show intense absorption bands at kmax values of 388 and 398 nm, respectively, attributable to the transitions of the respective C@N groups. The other high intensity bands observed in the UV region of both compounds are assignable to intraligand n–p⁄/p–p⁄ transitions [21].

Fig. 1. Thermograms of complexes 1 and 2.

3.3. Thermogravimetric analysis difference Fourier map. Although several geometrical positions were possible, refinement of hydrogen atoms placed there did not give reproducible results. Therefore, these atoms were omitted from the refinement but included in the molecular formula for all derived data. Crystallographic data and refinement details for the compounds are summarized in Table 1. 3. Results and discussion 3.1. Synthesis Both the complexes 1 and 2 were obtained as red crystalline solids by reacting nickel perchlorate, cadmium chloride and the respective tetradentate Schiff base ligand in a 1:1:1 molar ratio in methanol medium. It was observed that a change in the alkyl group (CH3 group in H2L to C2H5 in H2L0 ) of the Schiff base ligand yielded two different bimetallic species, tetranuclear 1 and trinuclear 2. The complexes have been characterized by elemental analysis, IR spectroscopy, electrical conductivity and magnetic susceptibility measurements, as well as by thermogravimetric and single crystal X-ray structural analysis. In methanol solution, complex 1 behaves as a non-electrolyte while 2 behaves as a 1:1 electrolyte, as is evident from their KM values (ca. 6 and 120 X1 cm2 mol1, respectively). Room temperature magnetic susceptibility measurements show that both the complexes are diamagnetic, indicating the absence of unpaired electrons. This is in conformity with the presence of square planar low spin 3d8 system of Ni(II) as well as the invariably diamagnetic 4d10 system of Cd(II) in both 1 and 2.

The TGA thermograms reveal that both compounds 1 and 2 are stable up to around 110 °C (Fig. 1). After this temperature, a steep weight loss up to 240 °C is observed in 1, followed by a gradual loss in weight up to 700 °C. In 2, however, the first stage of weight loss (3.4%) occurs between 110 and 160 °C, corresponding to the removal of the lattice water molecule simultaneously with the coordinated one. A horizontal portion of the TGA curve in the narrow region 160–210 °C suggests that no weight loss takes place in this temperature zone for 2. This is followed by a steep loss in weight up to 310 °C and a gradual loss up to the maximum temperature of the study. In summary, the thermogravimetric analyses reveal that compounds 1 and 2 undergo decomposition on heating without the formation of any intermediate product of good stability or definite composition. 3.4. Crystal structures of 1 and 2 The molecular structures of complexes 1 and 2 are displayed in Fig. 2. A few selected bond distances and angles are summarized in Table 2. The X-ray structural studies reveal that both compounds 1 and 2 consist of heterometallic assemblies of nickel(II) and cadmium(II) and have some common structural features. However, compound 1 comprises a tetranuclear unit of two nickel(II) and two cadmium(II) centers, unlike 2 in which a trinuclear unit of two nickel(II) and one cadmium(II) is present. The metal ions in 1 are arranged in the fashion Ni  Cd  Cd  Ni while those in 2 are Ni  Cd  Ni. The Cd  Cd and Ni  Cd distances in the former are 3.27 and 3.69 Å, respectively, whereas the two unequal Ni  Cd distances in the latter are 3.24 (Ni1  Cd1) and 3.25 Å (Ni2  Cd1).

Fig. 2. Molecular structures of the complexes 1 and 2.

D. Bandyopadhyay et al. / Polyhedron 30 (2011) 2678–2683 Table 2 Selected bond parameters of compounds 1 and 2. 1

2

Bond lengths (Å) Cd1–O1 Cd1–O23 Cd1–Cl32 Cd1–Cl31 Cd1–Cl31⁄

2.385(4) 2.248(3) 2.409(1) 2.499(2) 2.592(2)

Cd1–O1A Cd1–O2A Cd1–O1B Cd1–O2B Cd1–O1W Cd1–Cl2

2.270(2) 2.370(2) 2.281(2) 2.406(2) 2.342(3) 2.477(8)

Ni4–O1 Ni4–O23 Ni4–N10 Ni4–N14

1.824(3) 1.853(4) 1.848(4) 1.852(4)

Ni1–O1A Ni1–O2A Ni1–N1A Ni1–N2A Ni2–O1B Ni2–O2B Ni2–N1B Ni2–N2B

1.844(2) 1.834(2) 1.851(3) 1.848(3) 1.839(2) 1.834(2) 1.855(3) 1.857(2)

Cd1  Ni1 Cd1  Ni2 Ni1  Ni2

3.243 3.254 4.237

O1A–Cd1–O1B O1A–Cd1–O1W O1B–Cd1–O1W O1A–Cd1–O2A O1B–Cd1–O2A O1W–Cd1–O2A O1A–Cd1–O2B O1B–Cd1–O2B O1W–Cd1–O2B O12–Cd1–O2B O1A–Cd1–Cl2 O1B–Cd1–Cl2 O1W–Cd1–Cl2 O2A–Cd1–Cl2 O2B–Cd1–Cl2 O2A–Ni1–O1A O2A–Ni1–N2A O1A–Ni1–N2A O2A–Ni1–N1A O1A–Ni1–N1A N2A–Ni1–N1A Ni1–O1A–Cd1 Ni1–O2A–Cd1 O2B–Ni2–O1B O2B–Ni2–N1B O1B–Ni2–N1B O2B–Ni2–N2B O1B–Ni2–N2B N1B–Ni2–N2B Ni2–O2B–Cd1 Ni2–O1B–Cd1

137.1(7) 103.0(1) 103.6(1) 64.3(7) 88.5(8) 166.9(1) 83.6(7) 62.8(7) 91.4(1) 89.8(8) 109.7(6) 107.0(6) 81.6(7) 99.7(6) 166.0(6) 84.3(1) 95.3(1) 177.2(1) 173.3(1) 92.5(1) 88.1(1) 103.5(1) 100.2(1) 83.4(1) 171.5(1) 94.0(1) 94.8(1) 173.0(1) 88.7(1) 99.4(1) 103.8(1)

Intramolecular metal–metal distances (Å) 3.693 Cd1  Cd1⁄ Cd1  Ni4 3.274 Ni4  Ni4⁄ 8.879 Bond angles (°) O1–Cd1–O23 O1–Cd1–Cl32 O1–Cd1–Cl31 O1–Cd1–Cl31⁄ O23–Cd1–Cl32 O23–Cd1–Cl31 O23–Cd1–Cl31⁄ Cl32–Cd1–Cl31 Cl32–Cd1–Cl31⁄ Cl31–Cd1–Cl31⁄ Cd1–Cl31–Cd1⁄ Cd1–O1–Ni4 Cd1–O23–Ni4 O1–Ni4–O23 O1–Ni4–N10 O1–Ni4–N14 N10–Ni4–N14 N10–Ni4–O23 N14–Ni4–O23

64.4(1) 99.6(1) 89.0(1) 154.9(1) 118.6(1) 115.1(1) 95.0(1) 123.9(6) 103.3(6) 87.0(4) 93.0(4) 101.3(2) 105.6(2) 84.5(2) 95.0(2) 175.5(2) 88.2(2) 179.0(2) 92.4(2)

Hydrogen bond dimensions Donor (D)

Hydrogen (H)

Acceptor (A)

\(DHA) (°)

D(D–H) (Å)

D(H  A) (Å)

D(D  A) (Å)

1 C9 C9 C16

H91 H92 H163

Cl32 Cl32 Cl32

150 158 145

0.96 0.97 0.97

2.87 2.79 2.89

3.732 3.703 3.722

2 O1W O1W

H1W1 H2W1

O2W Cl2

165 127

0.94 0.94

1.81 2.82

2.725 3.465

In 1, the two cadmium(II) centers in the complex unit are linked through doubly bridging chlorine functions and each Cd(II) center is connected to one of the [NiL] units via two bridging phenolate oxygen atoms contributed by the Schiff base ligand L2. In 2, however, the single central cadmium(II) ion is connected simultaneously to two [NiL0 ] units through two doubly bridged phenolate oxygen atoms contributed by L0 2. Thus, every cadmium(II) ion adopts a distorted square pyramidal geometry

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(CdO2Cl3) in 1. The bridging two chlorine (Cl31, Cl31) and two oxygen atoms (O1, O23) constitute the basal plane while another chlorine atom (Cl32) occupies the apical position to form the five-coordinated coordination sphere around each cadmium(II) ion. In the case of 2, the cadmium ion adopts a severely distorted octahedral geometry with a CdO5Cl chromophore. The irregular hexacoordination environment around the Cd(II) ion comprises a chloride ion (Cl2) and five oxygen atoms, four (O1A, O2A, O1B, and O2B) of which are bridging phenolate oxygen atoms and the fifth (O1W) is from a water molecule. In both 1 and 2, all the nickel(II) ions adopt distorted square planar geometries with NiN2O2 chromophores. The four coordination of nickel(II) in 1 is completed by two imino nitrogen atoms (N10, N14) and the above-mentioned two oxygen atoms (O1, O23) donated by L2. However, the two nickel(II) centers in 2 are non-equivalent and the four coordination of each is satisfied by two imino nitrogen and two phenolic oxygen atoms, viz., N1A, N2A, O1A, O2A for the Ni1 ion and N1B, N2B, O1B, O2B for the Ni2 ion. The electroneutrality of 2 is maintained by the presence of the perchlorate anions in the lattice. The distortions in the coordination spheres of the metal ions from the ideal geometries are obvious due to the structural constraints imposed by the polydentate ligand frameworks present in 1 and 2, which are neither planar nor symmetric. The Ni–N and Ni–O bond distances in the [NiL] and [NiL0 ] units, ranging from 1.824 to 1.857 Å, agree well with other similar Schiff base complexes of nickel(II). All the Cd–Cl (2.409–2.592 Å) and Cd–O (2.270–2.406 Å) bond distances in 1 and 2 are well matched with previously reported cadmium(II) complexes. All the relevant bond angles around the metallic centers in the two complexes are also more or less similar as expected from a stereochemical point of view. The cisoid and transoid angles around the nickel(II) ions in 1 and 2 range from 83.4–95.3° to 171.5–179.0°, respectively. The [CdO2Cl3] unit in 1 undergoes distortions from an ideal square pyramidal geometry, which is evident from its wide ranges of cisoid and transoid angles, being 64.4–123.9° and 115.1–154.9°, respectively. Again, it is observed that both the two chlorine bridging angles (Cd1–Cl31–Cd1⁄) are the same but the corresponding phenolate oxygen bridging angles (Ni4–O1–Cd1) and (Ni4–O23–Cd1) differ to some extent in 1. In 2, however, the distortion of the [CdO5Cl] unit from an ideal octahedral geometry is much larger as is reflected from its wider ranges of bond angles, viz. 64.25–166.94°. Thus, a binuclear core of two symmetry-related [LNiCdCl] units connected together via two chlorine atom bridges are formed in compound 1. A crystallographic center of inversion lies at the midpoint of the Cd  Cd vector. Compound 2 is much more distorted and strained, unlike 1, as is evident from its bond parameters; all the Ni–O–Cd angles are unequal and the Ni  Cd  Ni angle is only 81.40°. The magnitudes of all the bond parameters of 1 and 2, however, are comparable to those of similar other chloro-bridged cadmium(II) and oxo-bridged nickel(II) complexes reported earlier [9–12,22–24]. The crystal packing diagrams of compounds 1 and 2 are presented in Fig. 3. The molecules of 1 are rather loosely held and are isolated from each other, as is evident from their packing in the ac plane (Fig. 3a), but when viewed through the bc plane of the lattice (Fig. 3b), C–H  Cl hydrogen bonding is found to be operative, holding the molecules together. Each Cl32 atom of the [CdO2Cl3] units in one molecule interacts with three hydrogen atoms (H91, H92, H163) linked to carbon atoms (C9, C16) of the Schiff base ligand of another molecule. The respective Cl  H distances are 2.868, 2.788 and 2.887 Å (Table 2). Thus, weak intermolecular attractions operate in 1 to build up a hydrogen-bonded 2D supramolecular network in its solid state. It is observed that the bridging chlorine atoms (Cl31) of the [CdO2Cl3] units are not involved in such hydrogen bonding. Similar weak intermolecular H-bonding interactions are also operative in 2 (Fig. 3c). Each Cl2 atom of the [CdO5Cl] units in

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Fig. 3. Structural packing diagrams: projection along the (ac) plane (a) and the (bc) plane (b) of the unit cell of 1; projection along the (bc) plane (c) of the unit cell of 2.

one molecule interacts with the hydrogen atom (H2W1) linked to the oxygen atom (O1W) of the coordinated water of another molecule. Similarly, the O2W atom present in the lattice water molecule is also involved in H-bonding via another hydrogen atom (H1W1) linked to the oxygen atom (O1W). However, since discrete hydrogen atom positions could not be located or refined, no hydrogen bond extending from O2W is noticed. The perchlorate anions within the interstices of the lattice of 2 are connected only loosely by van der Waals interactions.

Acknowledgements

4. Conclusion

CCDC 815140 and 826098 contain the supplementary crystallographic data for 1 and 2. These data can be obtained free of charge via http://www.ccdc.cam.ac.uk/conts/retrieving.html, or from the Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: (+44) 1223-336-033; or e-mail: [email protected].

The synthesis and characterization of two new heteropolynuclear Schiff base complexes containing cadmium(II) and nickel(II) metal centers with different geometries have been described in this paper. The characteristic features of the complexes include the presence of doubly bridging phenolate oxygen and chlorine functions between Cd(II)  Ni(II) and between Cd(II)  Cd(II) ions, respectively. Intermolecular C–H  Cl, O–H  Cl and O–H  O hydrogen bonding interactions have been observed that build up 2D supramolecular structures in the solid state of the complexes. In addition to the synthetic investigation, this study demonstrates the interesting structural variations of heteropolymetallic Schiff base complexes containing both 3d and 4d transition metal ions.

Our thanks are extended to Rt. Revd. Dr. P.K. Dutta (Chairman of Governing Body), Dr. R.N. Bajpai (Principal) and Dr. S.K. Roy (Head, Chemistry Department) of Bankura Christian College for their constant encouragement and valuable suggestions on carrying out this work. We also thank Mr. Kalyan Dana for his assistance. Appendix A. Supplementary data

References [1] V. Balzani, M.G. Lopez, J.F. Stoddart, Acc. Chem. Res. 31 (1998) 405. [2] Special Issue on ‘‘Molecular Materials in Electronic and Optoelectronic Devices’’, Acc. Chem. Res. 32 (1999) 191. [3] P. Comba, T.W. Hambley, Molecular Modelling of Inorganic and Coordination Compounds, second ed., VCH, Weinheim, 2001. [4] T. Soma, H. Yuge, T. Iwamoto, Angew. Chem., Int. Ed. Engl. 33 (1994) 1665.

D. Bandyopadhyay et al. / Polyhedron 30 (2011) 2678–2683 [5] B.F. Abraham, M.J. Hardie, B.F. Hoskins, R. Robson, E.E. Sutherland, J. Chem. Soc., Chem. Commun. (1994) 1049. [6] M. Veith, S. Mathur, V. Huch, J. Am. Chem. Soc. 118 (1996) 903. [7] J.-M. Lehn, Supramolecular Chemistry, Concepts and Perspectives, VCH, Weinheim, Germany, 1995. [8] J.W. Steed, J.L. Atwood, Supramolecular Chemistry, John Wiley and Sons, New York, 2000. [9] Y.-Y. Ge, G.-B. Li, H.-C. Fang, X.-L. Zhan, Z.-G. Gu, J.-H. Chen, F. Sun, Y.-P. Cai, P.K. Thallapally, Cryst. Growth Des. 10 (2010) 4987. [10] D. Bose, Sk.H. Rahaman, R. Ghosh, G. Mostafa, J. Ribas, C.-H. Hung, B.K. Ghosh, Polyhedron 25 (2006) 645. [11] D. Maity, P. Mukherjee, A. Ghosh, M.G.B. Drew, G. Mukhopadhyay, Inorg. Chim. Acta 361 (2008) 1515. [12] C.N. Verani, E. Rentschler, T. Weyhermüller, E. Bill, P. Chaudhuri, J. Chem. Soc., Dalton Trans. (2000) 251. [13] S. Mandal, G. Rosair, J. Ribas, D. Bandyopadhyay, Inorg. Chim. Acta 362 (2009) 2200. [14] NONIUS, Kappa CCD Program Package: COLLECT, DENZO, SCALEPACK, SORTAV, Nonius BV, Delft, The Netherlands, 1999.

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[15] Bruker-Nonius, Apex-II and Saint-Plus (Version 7.06a), Bruker AXS Inc., Madison, Wisconsin, USA, 2004. [16] Z. Otwinowski, W. Minor, Methods Enzymol., Part A 276 (1997) 307. [17] A. Altomare, M.C. Burla, M. Camalli, G.L. Cascarano, C. Giacovazzo, A. Guagliardi, A.G.G. Moliterni, G. Polidori, R. Spagna, J. Appl. Crystallogr. 32 (1999) 115. [18] D.J. Watkin, C.K. Prout, J.R. Carruthers, P.W. Betteridge, CRYSTALS 11, Chemical Crystallography Laboratory, Oxford, UK, 1999. [19] G.M. Sheldrick, Acta Crystallogr., Sect. A 64 (2008) 112. [20] K. Nakamoto, Infrared and Raman Spectra of Inorganic and Coordination Compounds, sixth ed., John Wiley and Sons, Inc., New Jersey, 2009. [21] A.B.P. Lever, Inorganic Electronic Spectroscopy, second ed., Elsevier Science, New York, 1984. [22] C.F. Huang, H.H. Wei, G.H. Lee, Y. Wang, Inorg. Chim. Acta 279 (1998) 233. [23] C. Hopa, M. Alkan, C. Kazak, N.B. Arslan, R. Kurtaran, J. Chem. Crystallogr. 40 (2010) 160. [24] R. Karmakar, C.R. Choudhury, D.L. Hughes, S. Mitra, Inorg. Chim. Acta 360 (2007) 2631.