Nucleophilic attack on coordinated CO in [Tc(CO) 4(PPh 3) 2]BF 4

Abstract

Several new technetium nucleophile-carbonyl adducts have been synthesized and characterized. Treatment of the Tc I cation, trans-[Tc(CO) 4(PPh 3) 2]BF 4 ( 1 with LiEt 3BH affords the Tc formyl complex Tc(CO) 3(C(O)H)(PPh 3) 2 ( 2) in 76% yield. Reaction of 2 with 1 equiv. of CH 3SO 3CF 3 in toluene produces the Fischer carbene [Tc(CO) 3(C(OMe)H)(PPh 3) 2]SO 3CF 3 ( 3) The nucleophile OH − reacts with 1 to give the hydroxycarbonyl complex Tc(CO) 3(C(O)OH)(PPh 3) 2 ( 4). If this reaction is carried out in the presence of alkyl alcohols, ROH [R = Me ( 5), Et ( 6)] the corresponding alkoxycarbonyl complexes Tc(CO) 3(C(O)OR)(PPh 3) 2 are obtained. Thearyloxycarbonyl complex Tc(CO) 3(C(O)OR)(PPh 3) 2 ( 7) (where R = C 6H 4CH 3) was prepared from the reaction of 4 with excess KOR in THF. Treatment of 1 with NaN 3 gives the isocyanate complex Tc(CO) 3(NCO)(PPh 3) 2 ( 8).