Synthesis and alkylation of [Fe(CN) 2(C 5H 5)(CO)] −, [Mo(CN) 2(C 5H 5)(CO) 2] −, [W(CN) 2(C 2H 5)(CO) 2] − and [W(CN)(C 5H 5)(CO) 3] −

Abstract

[Fe(CN) 2(C 5H 5)(CO)] − was best prepared by reacting [FeBr(C 5H 5)(CO) 2] with potassium cyanide in aqueous ethanol. Two other syntheses were also found. Alkylation of the anion with alkyl halides gave two series of isocyanide complexes: neutral [Fe(CN)(C 5H 5)(CO)(CNR)] and cationic [Fe(C 5H 5)(CO)(CNR)] +. The reaction of potassium cyanide with [WCl(C 5H 5)(CO) 3] gave [W(CN)(C 5H 5)(CO) 3] and K[W(CN) 2(C 5H 5)(CO) 2]; [MoCl(C 5H 5)(CO) 3] gave only K[Mo(CN) 2·(C 5H 5)(CO) 2]. Alkylation of the tungsten monocyanide complex with methyl iodide gave the isocyanide complex [W(C 5H 5)(CO) 3(CNCH 3)]I and alkylation of the molybdenum dicyanide complex gave [Mo(C 5H 5)(CO) 2(CNCH 3) 2]I. Attempts to form other cyclopentadienyl-carbonyl-cyanide complexes were unsuccessful.