Übergangsmetall-fulven-komplexe: XXVIII. Reaktionen von (fulven)Cr(CO) 3-komplexen und α-ferrocenyl-carbeniumionen mit nukleophilen

Abstract

Tricarbonyl(fulvene)chromium complexes react with anionic nucleophiles to give functionally substituted cyclopentadienyl derivatives. The nucleophilic attack occurs at the exocyclic carbon atom of the fulvene ligand. Addition of PPh 2 − to (η 6-6,6-dimethylfulvene)Cr(CO) 3 ( 1) yields the novel anion [(η 5-C 5H 4C(CH 3) 2PPh 2)Cr-(CO) 3] −, which can be isolated as a K +, (C 2H 5) 4N +, (C 6H 5) 4P +, or Tl + derivative ( 2–5). The potassium salt of the uncoordinated C 5H 4C(CH 3) 2PPh 2 − anion ( 7) is obtained by treatment of 6,6-dimethylfulvene with KPPh 2·2C 4H 8O 2. Similarly, NaC 5H 5 reacts with 1 to give Na[(η 5-C 5H 4C(CH 3) 2C 5H 5)Cr(CO) 3] ( 8). The reactions of (6-dimethylaminofulvene)Cr(CO) 3 ( 15) with nucleophiles are accompanied by elimination of dimethylamine. Addition of Ph 3PCH 2 to 15 gives an unstable product, but after reaction of 6-dimethylaminofulvene with Ph 3PCH 2, the free ligand C 5H 4CHCHPPh 3 ( 17) can be isolated in moderate yields. Deeply colored anions of the type [(η 5:η 5-C 5H 4C(R)C 5H 4)Cr 2(CO) 6] − (R = H, N(CH 3) 2) are synthesized by reaction of 15 or (6-dimethylamino-6-methylthiofulvene)Cr(CO) 3 with NaC 5H 5 and subsequent complexation of the mononuclear intermediate with (CH 3CN) 3Cr(CO) 3. In addition, the synthesis of the new fulvene complexes [C 5H 4CH(CHCH) 2N(CH 3)Ph]M(CO) 3 ( 23, 24; M = Cr, Mo) is described. The investigation is extended to α-ferrocenylcarbenium ions, which are isoelectronic with (fulvene)Cr(CO) 3 complexes. [(η 5-C 5H 5)Fe(C 5H 4CPh 2)] + BF 4 − ( 25) adds tertiary phosphines at the exocyclic carbon atom to give phosphonium salts of the type [(η 5-C 5H 5)Fe(C 5H 4CPh 2PR 3)] +BF 4 −. A CO-substititution product of a tricarbonyl (fulvene)chromium complex is obtained for the first time by irradiation of (η 6-6,6-diphenylfulvene)Cr(CO) 3 in the presence of PPh 3. In addition, an improved synthesis of the (CH 3CN) 3M(CO) 3 complexes (M = Cr, Mo, W) is reported.