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Four succinato-bridged complexes of copper(II) have been synthesized. Complex 1, [Cu(2)(mu-OH(2))(2)L(bpy)(2)(NO(3))(2)](n) and 2, [Cu(2)(mu-OH(2))(2)L(phen)(2)(NO(3))(2)](n)(bpy = 2,2[prime or minute]-bipyridine; phen = 1,10-phenanthroline and LH(2)= succinic acid) exhibit 1D coordination polymer structures where both the nitrate ions are directly linked to the copper(ii) producing synthons in a 2D sheet. A novel 2D grid-like network, ([Cu(4)L(2)(bpy)(4)(H(2)O)(2)](ClO(4))(4)(H(2)O))n3, is obtained upon changing the nitrate by perchlorate anion in complex 1, where the channels are occupied by the anions. On changing the nitrate by tetrafluoroborate anion in complex 2, a novel octanuclear complex, [Cu(8)L(4)(phen)(12)](BF(4))(8).8H(2)O 4, is isolated. The coligand bpy and phen in these complexes show face-to-face (in 1,2,3,4) or edge-to-face (in 4 )pi-pi interactions forming the multidimensional supramolecular architectures. Interestingly, the appearance of edge-to-face pi-pi interactions in complex facilitates the formation of discrete octanuclear entities. Variable-temperature (300-2 K) magnetic measurements of complexes have been done. Complexes 1 and 2 show very weak antiferromagnetic (OOC-CH(2)-CH(2)-COO) and ferromagnetic coupling (mu-H(2)O). Complex 3 also shows antiferromagnetic (syn-syn mu-OCO), and ferromagnetic coupling (mu-O of the -COO group). Complex 4 with two types (syn-syn and syn-anti) of binding modes of the carboxylate group shows strong antiferromagnetic interaction.

A deep green complex, [Cu(L)(μ-Br)Br]2 (L = 1,4-diazacycloheptane) was synthesized and its crystal structure and magnetic properties have been studied. The structure determination reveals that in the binuclear unit each copper(II) occupies a distorted square pyramidal geometry in which each bridging bromine atom is simultaneously ligated in axial and equatorial positions between two adjacent copper(II) centres. The binuclear units are packed along the [101] direction. Each dimer is connected to its two nearest neighbours by two Cu–(μ-Br)⋯H–N–Cu hydrogen bonding interactions resulting in an infinite 1D ladder-like chain. The magnetic data were fitted considering the interdimer interactions using different models to obtain precise results and the susceptibility vs. temperature curve for the complex exhibits a maximum at 12 K indicating antiferromagnetic behaviour. Magneto-structural correlations have also been carried out.

Two novel 2D polymers of cadmium(II), [Cd(medien)(SeCN)2]n (1) (medien = N″-methyldiethylenetriamine) and [Cd2(iprdien)(SeCN)4]n (2) (iprdien = N′-isopropyldiethylenetriamine) have been synthesized and their molecular structure determined by X-ray crystallography. In complex 1 each octahedral cadmium(II) unit of a 1D coordination chain contains one pendant SeCN, binding through Se. These pendant SeCN form mutual relationships with other 1D chains through non-covalent interactions (H-bonding) giving rise to a 2D infinite sheet like structure. The molecular structure of 2 reveals a 2D infinite coordination polymer possessing alternating N-bonded octahedral and Se-bonded tetrahedral cadmium(II) centres exhibiting symbiotic phenomena. Both complexes undergo melting but complex 1 remains as a supercooled liquid in the temperature region 78–131 °C.

A one pot reaction of Cu(NO3)2, malonate dianion (mal) and 1,2-bis(4-pyridyl)ethane (bpe) leads to a novel 3D open framework, [{Cu3(mal)2(bpe)3(H2O)2}(NO3)2(H2O)2]n (1), composed of Cu–malonate layers pillared by bidentate bpe ligands encapsulating NO3− and water molecules in bidirectional intersecting channels; the framework's secondary building unit comprises unprecedented two hexa- and four penta-coordinate copper(II) nodes which are 6- and 4-connecting, respectively, and the magnetic properties of the complex show the highest overall ferromagnetic interaction (J = 22 cm−1) of the previously reported syn–anti carboxylate bridged complexes.

A unique three-dimensional coordination polymer of cadmium(II), [Cd(C4O4)(H2O)2]n1 (C4O42−⊕=⊕squarate dianion), has been synthesized and characterized by single crystal structural analysis. The molecular structure shows that each bridging squarate dianion functions as a four-fold monodentate ligand to form a cage-like channel network. The compound crystallizes in the rhombohedral system, space group R (no. 148) with a⊕=⊕b⊕=⊕11.765(6) A and c⊕=⊕14.920(7) A, γ⊕=⊕120°, Z⊕=⊕9, V⊕=⊕1788.5(15) A3. Thermal investigation reveals that the dehydrated compound is remarkably stable.