摘要
Distorted square planar [Ni(CO)(SR) n (SePh) 3-n ] - (n = 0 (1), 3 (2), 1 (3) or 2 (4); R = Ph or C 4 H 3 S) complexes, were prepared by unique Cp - /PhS - (PhSe - ) exchange reactions and oxidative addition. (SC 4 H 3 S) 2 , [NiCp(CO)] 2 and 2 equivalents of fac-[N(PPh 3 ) 2 ][Fe(CO) 3 (SC 4 H 3 S) 3 ] in thf led to the isolation of [N(PPh 3 ) 2 ][Ni(CO)(SC 4 H 3 S) 3 ] and [FeCp(CO) 2 (SC 4 H 3 S)]. Complex [Ni 0 (CO) 3 (SePh)] - was obtained upon chemical reduction of complex [Ni II (CO)(SePh) 3 ] - with [BH 4 ] - under a CO atmosphere in thf. [Ni II (CO)(SePh) 3 ] - was reobtained upon oxidative addition of diphenyl diselenide and benzeneselenol to [Ni 0 (CO) 3 (SePh)] - in thf. The mixed-chalcogenolate nickel(II) carbonyl complexes [Ni(CO)(SPh) n (SePh) 3-n ] - (n = 1 or 2) were prepared by PhSe - /PhS - ligand exchange reaction and oxidative addition of diphenyl disulfide to [Ni(CO) 3 (SePh)] - individually. Complexes [Ni II (CO)(SePh) 3 ] - , [Ni II (SC 5 H 4 N) 3 ] - , [Ni 0 (CO) 3 (SC 5 H 4 N)] - and [Ni 0 (CO) 3 (SePh)] - are chemically interconvertible at ambient temperature. Coordinative addition of the metalloanion [Mn(CO) 5 ] - ([Fe(CO) 4 (SePh)] - ) to complex [Ni(CO) -(SePh) 3 ] - and subsequent redox under a CO atmosphere led to formation of cis-[Mn(CO) 4 (SePh) 2 ] - (fac-[Fe(CO) 3 -(SePh) 3 ] - ) and [Ni 0 (CO) 3 (SePh)] - . Nickel(IIl)/nickel(0) carbonyl thiolate complexes are more unstable thermally than the corresponding carbonyl selenolate complexes. Isotopic shift experiments demonstrate the lability of carbonyl ligand(s) of complexes 1-4 and [Ni(CO) 3 (SePh)] - species. The vibrational spectroscopy of the Ni II (CO) fragment (v(CO) ranges from 2023 to 2043 cm -1 ) found in 1-4 may be regarded as a spectroscopic reference for the carbonyl binding site of [NiFe] hydrogenases and CO dehydrogenase. © The Royal Society of Chemistry 2001.