New functionalized homoleptic dithiocarbamates of the form [M(L) 2 ] (M = Ni(II), L = L1, N-(3-methoxybenzyl)-N-(methylbenzyl)dithiocarbamate (1), L3, N-(3,4,5-trimethoxybenzyl)-N-(3-methylpyridyl)dithiocarbamate (3), L4, N-(4-methoxybenzyl)-N-benzyldithiocarbamate (4); Pd(II), L2, N-(N 0 -methyl-2-pyrrole)-N-benzyldithiocarbamate (2)) have been synthesized and characterized by microanalysis and their structures have been investigated using X-ray crystallography. All the four structures are centrosymmetric with the metal located in a square plane with minor distortions, Pd(II) greater than Ni(II). The crystal structures of 1 and 2 revealed the existence of unique intermolecular C-HÁ Á ÁM (Ni, Pd) anagostic interactions between the methylene hydrogen atom on the ligand substituents and the metal centres and these enable the formation of 1-D polymeric chains. Particularly, geometric parameters (PdÁ Á ÁH-C = 2.61 Å; +PdÁ Á ÁH-C = 1731) for the C-HÁ Á ÁPd interactions in 2 are at the border of anagostic and hydrogen bonding. By contrast, 4 shows interactions between the methylene hydrogen atom and the CS 2 Ni ring rather than the metal alone, while the interaction in 3 is intermediate between the two aforementioned types. These interactions are not shown in solution as revealed by their 1 H NMR studies. DFT calculations have been performed to analyse these rare interactions. 1, 3 and 4 are weakly conducting, s rt = 10 À10 -10 À12 S cm À1 , and show semiconductor behaviour in the 313-373 K range.

No abstract

No abstract

New heteroleptic complexes, [M(dithiolate-dppf)] (M=Ni(II) 1,Pd (II) 2, dithiolate = 2-(methylene-1,1'-dithiolato)-1,3-indandione (L1); Pd(II) 3, 2-(methylene-1,1'-dithiolato)-5,5'-dimethylcyclohexane-1,3-dione (L2); dppf = 1,1'-bis(diphenylphosphino)ferrocene) have been synthesized and characterized by elemental analysis, spectroscopy (IR, UV-Vis., 1 H, 13 C and 31 P NMR) and cyclic voltammetry. X-ray crystallography revealed distorted square planar geometry with P 2 MS 2 cores in 1-3, displaying M···HÀC intramolecular anagostic interactions. Complexes 1-3show luminescent characteristics in CH 2 Cl 2 solution at room temperature emanating from the MLCT charge-transfer state. Based on their optical and electrochemical properties, the sensitizing activities of 1-3 have been explored; the Ni complex 1 has shown significant light to electrical energy conversion efficiency with h value of 0.78%. All the three complexes with s rt , 10 À6 -10 À7 S cm À1 and E a = 1.00-1.35 eV are weakly conducting but show semiconducting characteristic in the 303-363 K temperature range.