Übergangsmetall‐Stannyl‐Komplexe, 7. Darstellung von Carben‐Komplexen (π1‐Aromat)(CO)₂CrCR₂ durch Umsetzung der anionischen Stannyl‐Komplexe [(π1‐Aromat)(CO)₂CrSnPh₃]^– mit R₂CX₂ oder [R₂CX]Y

Abstract

Transition Metal Stannyl Complexes, 7 [1] . – Preparation of Carbene Complexes (π1‐Arene)(CO) 2 CrCR 2 by the Reaction of the Anionic Stannyl Complexes [(π1‐Arene)(CO) 2 CrSnPh 3 ] – with R 2 CX 2 or [R 2 CX]Y Carbene complexes (π1‐arene)(CO) 2 CrCR 2 are formed in substitution/elimination reactions from the anionic stannyl complexes K[(π1‐arene)(CO) 2 CrSnPh 3 ] [π1‐areneC 6 H 6 ( 1a ), 1,3,5‐Me 3 C 6 H 3 ( 1b ), 1,2,4,5‐Me 4 C 6 H 2 ( 1c )] C 6 Me 6 ( 1d ) and organic dihalides R 2 CX 2 containing activated C – X bonds or ionic halides [R 2 CX]Y. Bis(stannyl) complexes (π1‐arene)(CO) 2 Cr(SnPh 3 ) 2 ( 3 ) and hydrido(stannyl)complexes (π1‐arene)(CO) 2 Cr(H)SnPh 3 are formed as byproducts due to the reaction of the eliminated Ph 3 SnCl with the anionic starting complexes or electron transfer reactions, respectively. The portion and ratio of the byproducts is largely influenced by the steric properties of both the (π1‐arene)(CO) 2 Cr fragment and the organic halide. Pyridinylidene complexes 2 ) are only obtained from 2‐chloro‐ N 1‐methylpyridinium tetrafluoroborat with 1a – c , but not with 1d . With the sterically less demanding halides [R 2 NC(H)Cl]Cl [NR 2 NMe 2 , ( n 3, 4)] or 3,3‐dichloro‐1,2‐diphenylcyclopropene the carbene complexes (π1‐arene)(CO) 2 CrC(H)NR 2 or are obtained with all employed π1‐arene ligands.