Mononuclear half-sandwich rhodium complexes containing phenylchalcogenolato ligands: a multinuclear ( 1H, 13C, 31P, 77Se, 103Rh, 125Te) magnetic resonance study

Abstract

Diphenyl dichalcogenides react with CpRh(PMe 3)(CO) ( 1) to give the cyclopentadienyl complexes CpRh(PMe 3)(EPh) 2 (E=S ( 2a), Se ( 2b) and Te ( 2c)) and carbon monoxide. The analogous pentamethylcyclopentadienyl complexes Cp*Rh(PMe 3)(EPh) 2 (E=S ( 4a), Se ( 4b) and Te ( 4c)) were prepared from Cp*Rh(PMe 3)Cl 2 ( 3) and the chalcogenolates, NaSPh or LiEPh (E=Se, Te). With 1,2-benzenedithiol in the presence of triethylamine, CpRh(PMe 3)(S 2C 6H 4), ( 6a) and Cp*Rh(PMe 3)(S 2C 6H 4) ( 7a) could be obtained starting from either CpRh(PMe 3)I 2 ( 5) or Cp*Rh(PMe 3)Cl 2 ( 3), respectively. The molecular geometry of Cp*Rh(PMe 3)(SePh) 2 ( 4b) was determined by a single crystal structure analysis which confirmed a distorted tetrahedral arrangement of the ligands. All compounds were characterised by 1H-, 13C-, 31P-, 103Rh- and, where possible, by 77Se- or 125Te-NMR spectroscopy. A negative sign of 1 J( 103Rh, 13C Cp) (reduced coupling constant 1 K( 103Rh, 13C Cp)>0) was determined by selective 13C{ 1H, 31P} triple resonance experiments for 2a and 4a– 4c.