880549-29-1Relevant articles and documents
Steric and electronic effects of substituents on planar nickel(II) complexes: Synthesis, NMR spectral and single crystal X-ray structural studies on nickel(II) dithiocarbamates with NiS2PN, NiS2PC, and NiS2P2 chromophores
Prakasam, Balasubramaniam Arul,Ramalingam, Kuppukkannu,Bocelli, Gabriele,Cantoni, Andrea
, p. 113 - 117 (2007/10/03)
Four new dithiocarbamatonickel(II) complexes [Ni(dchdtc)(NCS)(PPh 3)] (1), [Ni(dchdtc)(CN)(PPh3)] (2), [Ni-(dchdtc)(PPh 3)2]ClO4 (3), and [Ni(dchdtc)(dppe)]ClO 4 (4) (dchdtc = N,N-dicyclohexyldithiocarbamate anion, PPh 3 = triphenylphosphine, and dppe = 1,2-bis(diphenylphosphino)ethane) were prepared from the parent [Ni(dchdtc)2]. All four complexes were analyzed by CV, UV-vis, IR, and NMR (1H, 13C, and 31P) spectra. 13C NMR spectra of the complexes (1-4) show the most notable >N-...13CS2 signals at around 200 ppm. In the cyclohexyl ring, the α-CH carbon is deshielded to a greater extent on complexation. Extraordinary deshielding was observed for the 31P signal in all of the cases, indicating the effective bonding of phosphorus to the metal center. Single crystal X-ray structural analysis of the mixed ligand complexes (1-3) indicates a decrease in S-Ni-S bite angle when compared to that of the parent bis(dithiocarbamate), due to an increase in steric crowding around the central metal by the introduction of a bulky PPh 3. The trans effects on Ni-S bonds can be arranged in the following order: NCS- 3 -. The S 2C-...NA), because of the steric effect exerted by two PPh3 groups and dchdtc. The observed negative reduction potentials follow the order: 1 > 2 > 3, indicating the presence of a higher relative electron density on 1 compared to 2 and 3.
