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The synthesis of two new lead(II) coordination polymers, [Pb 2 (mpic) 4 (H 2 O)]·0.5H 2 O ( 1 ) and [Pb 2 (phen) 2 (cit)(mes)]·2H 2 O ( 2 ) has been reported, where mpic=3-methyl picolinate, phen= o -phenanthroline, H 2 cit=citraconic acid, H 2 mes mesaconic acid. X-ray single crystal diffraction analyses showed that the complexes comprise topologically different 1D polymeric chains stabilized by weak interactions and both containing tetranuclear Pb 4 units connected by carboxylate groups. In compound 1 3-methylpicolinic acid is formed in situ from 3-methyl piconitrile, and mesaconate and citraconate anions were surprisingly formed from itaconic acid during the synthesis of 2. The photoluminescence and thermal properties of the complexes have been studied.

Two new coordination polymers of Mn(II), of formula C12H18MnN8O6 (1) and C21H16MnO9 (2), have been synthesized by using two different kind of ligands, namely 5-methyl-7-oxo-(1,2,4)triazolo(1,5-a)pyrimidine (HmtpO) and 3-(2-furyl)prop-2-enoic acid (fproH). The X-ray single crystal structure analysis shows that complex 1 is a discrete molecular complex that turns into a 3D network through hydrogen bonding and π–π stacking interactions. Complex 2 is 1D polymeric chain comprising hexacoordinated Mn(II) centers. Luminescence study revealed the presence of intraligand π*–π transitions. The thermal stability of the complexes has been also investigated by thermogravimetric analysis. Two new coordination polymer of Mn(II) have been synthesized. X-ray single crystal structure analysis revealed that complex 1 is 3D via supramolecular interactions and complex 2 is a 1D chain. Luminescence and thermal characterization has been done for the complexes.

The structural determination of two interesting lead(II) coordination polymers, namely [Pb(ind)2(H2O)]n (1) and [Pb2(dbsf)2(bipy)]n (2) (Hind = indane-2-carboxylic acid, H2dbsf = 4,4′-sulfonyldibenzoic acid, and bipy 4,4′-bipyridine), reveals in the second an unexpected polyrotaxane 1D → 1D interpenetrated coordination polymer thanks to the hemidirected coordination geometry of the metal and the rings formed by the dicarboxybiphenyl sulfone ligands along the 1D chain.

A new 3D silver complex [Ag(mela)(H2O)(NO3)]n (1) (mela = melamine or 2,4,6-triaminotriazine) is synthesized and characterized by single crystal X-ray diffraction, IR, and elemental analysis. The structural characterization shows that the compound crystallizes in space group C c, a = 8.181(2), b = 10.269(3) c = 11.347(3) A, β = 105.88(2)°, Z = 4. Out of several structurally characterized transition metal compounds comprising melamine, the titled complex represents a rare example of μ 3 -melamine coordination mode realized through the heterocycle nitrogen donors. The fluorescent property of complex 1 was investigated and the mechanism was validated by means of a density functional theory (DFT) calculation. A new 3D silver complex was synthesized using the 2,4,6-triaminotriazine ligand. The X-ray structural analysis shows a highly distorted trigonal bipyramidal geometry of Ag(I) ion with a rare μ3-coordination mode of the ligand achieved through the heterocyclic nitrogen donors. Emission study reveals intraligand and ligand-to-metal charge transfer in the complex.

Three new coordination polymers of manganese(II) of formulae [Mn3(phen)2(phdac)3]·2H2O (1), [Mn(4,4′-bipy)(H2O)4](cbprop)(2) and [Mn(2,2′-bipy)(4-nph)(H2O)2]2 (3) (phen = 1,10-phenanthroline, 4,4′-bipy = 4,4′-bipyridine, 2,2′-bipy = 2,2′-bipyridine, H2phdac = 1,4-phenylenediacetic acid, H2cbprop = 4-carboxybenzenepropanoic acid and H2nph = 4-nitrophthalic acid) have been synthesized and structurally characterized by X-ray single-crystal diffraction analysis. The metal complexes possess 2D (1), 1D (2) and 0D (3) dimensionalities. In each case, the crystal packing shows three-dimensional architecture by means of π–π interactions and/or hydrogen bonding supported by coordinated and lattice water molecules. The emission spectra show metal-perturbed intra-ligand π*–π charge transfer transitions for 1 and π*–π and π*–n charge transfer transitions for 3.

Three coordination polymers of zinc(II) and cadmium(II) of formula {[Zn(bipy)(NIPH)]0.1·5H2O}n (1), {[Cd2(bipy)2(NIPH)2]·2H2O} n (2) and {[Cd2(bipy)4(BDAC)(NO3)](NO3)·6H2O}n (3) (NIPH = 5-nitro-isophthalic acid, H2BDAC = 1,4-benzenediacrylic acid and bipy = 2,2′-bipyridine) have been synthesized and structurally characterized by X-ray single crystal diffraction analysis. All the complexes display 1D coordination polymers where M(bipy) units are connected by dicarboxylate anions(and also by nitrate in 3)acting as bridging ligands. While in 1 and 3 a zig–zag chain is generated, in case of 2 a double linear chain is formed by the two crystallographic distinct Cd atoms. In solid state all the complexes expand the dimensionality to 3D by means of π–π interactions among π rings and H-bonds generated by lattice water molecules. The fluorescence study indicates intraligand π–π* charge transfer is the reason for emission in all the complexes.

Two lead(II) compounds [Pb3(idiac)3(phen)2(H2O)]·2(H2O) (1) and [Pb(ndc)]n (2), where H2idiac=iminodiacetic acid, phen=1,10-phenanthroline and H2ndc=naphthalene-2,6-dicarboxylic acid, have been synthesized and structurally characterized. Single crystal X-ray diffraction analysis showed that compound 1 is a discrete trinuclear complex (of two-fold symmetry) which evolves to a supramolecular 3D network via π–π interactions, while in compound 2 the naphthalene dicarboxylate anion act as a linker to form a three dimensional architecture, where the anion adopts a bis-(bidentate bridging) coordination mode connecting four Pb(II) centers. The photoluminescence property of the two complexes has been studied.

Two new cadmium coordination polymers have been synthesized with composition {[Cd2(tma)(atz)(H2O)]·(H2O)} n (1) (tmaH3 = benzene-1,3,5-tricarboxylicacid, atzH = 5-aminotetrazole) and [Cd(isoor)2(H2O)2] (2) (isoorH = isoorotic acid). X-ray single crystal structure analysis reveals that complex 1 is 3D coordination polymer. However 2 is mononuclear and turned 3D via hydrogen bonding. Thermogravimetric and luminescence characterization of the complexes were done. Two new 3D coordination polymers of cadmium have been synthesized by using benzene-1,3,5-tricarboxylicacid, 5-aminotetrazole and isoorotic acid. Both the complexes are characterized by X-ray single crystal structure, thermal and photoluminescence study.

Two new Ag(I) coordination polymers [Ag2(mepyz)](2,6-ndc)] n (1) and [Ag4(4,4′-bipy)]4(2,6-ndc)2·8(H2O) (2) (where 2,6-ndcH2 = 2,6-napthalene dicarboxylic acid, mepyz = 2-methyl pyrazine and 4,4′-bipy = 4,4′-bipyridine) have been synthesized and characterized by single crystal X-ray diffraction analysis. Complex 1 displays a 2D rectangular grid architecture comprising short Ag···Ag interactions, while 2 is a 1D coordination polymer: both enlarge their dimensionality to 3D via weak interactions. Luminescence study performed on complexes as well on ligands shows metal perturbed intraligand CT transition. Two new luminescent coordination polymers of Ag(I) have been synthesized. The X-ray structural determination analysis revealed 2D and 1D coordination polymers that enlarge dimensionality to 3D via weak supramolecular interactions.