| Popis: |
Department of Chemistry, Inorganic Chemistry Section, Jadavpur University, Kolkata-700 032, India E-mail : samaresh _ b@hotmail. com Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, UK Manuscript received 20 December 2011, revised 30 December 2011, accepted 30 December 2011 Reaction of a series of N-(aryl)picolinamide ligands (HL-R, where H denotes the acidic proton and R (R=OCH3, CH3, H, Cl and N02) is the para substituent in the aryl fragment) with RhCI3 ·3H20 in rcfluxing ethanol in the presence of a base (NEt3) affords two groups of yellow complexes of type [Rh(HL-R)(L-R)CI2) and [Rh(L-R)2 (H20)CI]. In [Rh(HL-R)(L-R)CI2], IIL-R is coordinated as neutral N,O-donor and L-R as monoanionic N,N-donm·, and the two chlorides are mutually trans. In [Rh(L-R)2(H20)Cl]both the amide ligands arc coordinated as monoanionic N,N-donor, and the chloro and aquo ligands are mutually cis. Structures of the [Rh(HL-OCH3)(L-OCH3)CI2) and [Rh(L-CI)2(H20)CI] complexes have been determined by X-ray crystallography. All the complexes show characteristic 1H NMR signals and intense LLCT transitions in the ultraviolet region. Cyclic voltammetry on the complexes shows an oxidation of the coordinated amide ligand within 0. 78-1.80 V vs SCE and a reductive response within -0.20 to -0.75 V vs SCE. DFT calculations have been done to explain the electronic spectral and electrochemical properties. |
