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Three new mononuclear complexes of copper(II), viz. [Cu(L)(N 3 )Cl] ( 1 ), [Cu(L′)(H 2 O)]ClO 4 ( 2 ) and [Cu(L″)] ( 3 ) where L = N -(3-aminopropyl)- N -methylpropane-1,3-diamine, L′ = 2-( N -{3-[(3-aminopropyl)(methyl)amino]propyl}ethanimidoyl)phenolate ion and L″ = 2,2′-{(methylimino)bis[propane-3,1-diylnitrilo(1 E )eth-1-yl-1-ylidene]}diphenolate ion, have been prepared. The synthesis of complex 1 has been achieved by reacting copper chloride with the triamine (L) and sodium azide in a 1:1:1 M ratio. The other two compounds have been synthesized by the reaction of copper perchlorate with the same triamine, L, plus 2-hydroxyacetophenone in a molar ratio of 1:1:1 (for 2 ) and 1:1:2 (for 3 ), so that the respective tetradentate and pentadentate Schiff bases HL′ and H 2 L″ are formed in situ to bind the copper(II) ions. The complexes have been characterized by microanalytical, spectroscopic and single crystal X-ray diffraction studies. Structural studies reveal that the mononuclear units of all the three complexes adopt a distorted square pyramidal geometry and are held together by either intermolecular H-bonding (in 1 and 2 ) or C–H⋯π interactions (in 3 ) to form supramolecular networks in the solid state.

Three new thiocyanato-bridged polymers of cadmium(II), [Cd(me4dpt)(SCN)2] n (1) [me4dpt = 3,3′-iminobis(N,N-dimethylpropylamine], [Cd(me2tn)(SCN)2] n (2) (me2tn = N,N′-dimethyl-1,3-propanediamine) and [{amphyH} {Cd(SCN)3}] n (3) (ampyH = 4-aminopyridinium cation), have been synthesized and their molecular structures determined through X-ray crystallography. In Complex 1 each square pyramidal mononuclear fragment is H-bonded (N − H…S) to form a 1D supramolecular chain. Complex 2 is a 1D coordination polymer in which each distorted octahedral cadmium(II) ion is linked with the four bridging thiocyanates and one diamine. The structure of 3 reveals anionic [Cd(SCN)3]− zigzag chains arranged in an approximately hexagonal array with the 4-aminopyridinum cations occupying triangular channels. Each chain is H-bonded (N−H…N) to form a 2D supramolecular network. Upon heating, 1 and 2 melt and transform to transparent solid masses at ambient temperature over a few days. On scratching, these turn to a fine powder. Th...

A mononuclear [Mn(mal)(bipy)(H2O)2] (1) and a dinuclear [Mn2(mal)(phen)3(H2O)2(Cl)]Cl (2) (mal=malonate dianion; bipy=2,2′-bipyridine and phen=1,10-phenanthroline) have been synthesised and structurally characterized by X-ray crystallography. The structure of complex 1 shows that each Mn(II) is linked with one bipy, two water molecules and a malonate ligand forming distorted octahedral environment and each mononuclear fragment through H-bonding interactions form 2D supramolecular network. The structure of complex 2 comprises to an asymmetric dinuclear cation which is bridged by a single anti–anti malonate ligand and chloride anions. The two distorted Mn(II) centres are separated by large distance 6.256(3) A due to the anti–anti bridging mode. The magnetic behavior of complex 2 studied in the temperature range 300–2 K corresponds to a weak antiferromagnetic coupling through the MnOCOMn anti–anti conformation. The magnetic data were fitted based on H=−2JS1·S2, yielding the intramolecular coupling constant J=−0.35 cm−1 with g=1.92 and R=1.255×10−4.

A tetranuclear ‘stepped wise’ copper(II) complex, [Cu4(μ2-OH)2(μ3-OH)2(2,2′-bipy)4Cl2]Cl2·6H2O has been synthesized and the crystal structure of the complex redetermined. The magnetic behavior has been investigated in the temperature range 300–4.2 K based on its novel binding modes of the OH−, i.e. OH− anions bridge the copper(II) centers in a bidentate (μ-2) as well as tridentate (μ-3) fashion and this shows ferromagnetic interactions. The fit of the experimental data was made by the irreducible tensor operator formalism (ITO) using the clumag program based on the Hamiltonian; H=−J1(S1S2+S3S4)−J2(S1S4)−J3(S1S3+S2S4) and the best fit parameters, assuming the g factors are identical and J2=J3, leads to J1=22.71 cm−1; J2=J3=0.34 cm−1 and g=2.10. The magnetic results are interpreted with structural parameters.

Two novel polymeric networks of cadmium(II), [Cd2(ibn)(SeCN)4]n (1) (ibn=1,2-diamino-2-methylpropane) and [Cd(pyz)(SeCN)2]n (2) (pyz=pyrazine) have been synthesised and their molecular structures have been determined by X-ray crystallography. The polymer 1 consists of two 1D parallel chains of Cd(II), each having alternate tetrahedral (CdSe4) and octahedral (CdN6) Cd(II) centres bridged through selenocyanate, exhibiting symbiotic phenomena. The octahedral Cd(II) centre of one chain is linked with the tetrahedral Cd(II) centre of another chain through selenocyanate ligand resulting 1D ladder like structure. The complex 2 is a 2D network of octahedral Cd(II) (CdN4Se2) in which doubly selenocyanato bridged 1D coordination polymeric chains are linked through pyrazine ligand in a bc plane forming rectangular grid like structure.

A three-dimensional supramolecular polymer of manganese(II), [{Mn(4,4′-bipy)(H2O)4}(C5O5)(H2O)2]n has been prepared and characterized by X-ray single crystal analysis. The polymer results from the mutual relationship of each coordination unit, [Mn(4,4′-bipy)(H2O)4]2+ through H-bonding between crystalline water and the encapsulated croconate dianion. Solid state thermal investigation shows stepwise elimination of water molecules and the 4,4′-bipyridine ligand.

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.