Health & Environmental Research Online (HERO)


Print Feedback Export to File
6919046 
Journal Article 
Rhodium complexes of 3,5-di-tert-butylcatechol : synthesis, structure and, spectral and electrochemical properties 
Sengupta, P; Bhattacharya, S; , 
2013 
Yes 
Journal of the Indian Chemical Society
ISSN: 0019-4522 
SCIENTIFIC PUBL-INDIA 
JODHPUR 
90 
2 
169-179 
English 
WOS:000209278900005 
Reaction of [Rh(PPh3)(3)Cl] with 3,5-di-tert-butylcatechol (H2DBC) in dry benzene affords a bis-semiquinonato rhodium(III) complex, [Rh(PPh3)(DBSQ)(2)Cl]. A similar reaction of [Rh(PPh3)(3)Cl] with a mixture of H2DBC and quinolin-8-ol (Hq) in 1 : 1 : 1 mole ratio affords a mixed-his complex or rhodium(III), [Rh(PPh3)(DBSQ)(q)Cl]. Formation of complexes [Rh(PPh3)(DBSQ)(2)Cl] and [Rh(PBh(3))(DBSQ)(q)Cl] is delieved to proceed through the intermediacy of a reactive hydrido complex, generated in the initial step via oxidative insertion of rhodium into the acidic O-H fragment of the ligand. Reaction of H2DBC with RhCl3 center dot 3H(2)O in ethanol yields a tris-semiquinonato complex of rhodium(III), [Rh(DBSQ)(3)]. Formation of this [Rh(DBSQ)(3)] complex proceeds through simple displacement reaction. Structures of all the three complexes have been determined by X-ray crystallography. The [Rh(PPh3)(DBSQ)(2)Cl] complex is diamagnetic and shows characteristic H-1 NMR spectrum, while complexes [Rh(PPh3)(DBSQ)(q)Cl] and [Rh(DBSQ)(3)] are one-electron paramagnetic, and show sharp ESR signal with g similar to 2.0. All the complexes show intense absorptions in the visible and ultraviolet regions. Cyclic voltammetry on all the three complexes shows an oxidation on the positive side of SCE and a reduction on the negative side, both of which are irreversible and ligand (DBSQ/q)-based.