Seven‐Coordinate MoII−Diiodo Complexes with Benzothiazole−N‐Heterocyclic‐Carbene Ligands and Their Mo0 Precursors: Synthesis, Structures, and Catalytic Application in the Epoxidation of cis‐Cyclooctene

Abstract

AbstractThe oxidative addition of I2 to molybdenum(0) complexes [Mo(CO)4(LNC)] (1–3; LNC1=1‐(benzothiazolin‐2‐yl)‐3‐allyl‐2‐ylidene; LNC2=1‐(benzothiazolin‐2‐yl)‐3‐benzylimidazol‐2‐ylidene; LNC3=1‐(benzothiazolin‐2‐yl)‐3‐methylimidazol‐2‐ylidene) afforded the first isolable and crystallographically elucidated seven‐coordinate MoII−diiodo complexes, [Mo(CO)3I2(LNC)] (4–6), with N‐heterocyclic carbene (NHC) ligands. The application of complexes 1–6 as precatalysts for the epoxidation of cis‐cyclooctene with tert‐butyl hydroperoxide (TBHP) as an oxidant has also been studied. Complexes 1–3 performed better than previously reported Mo0−carbonyl−NHC complexes, thereby producing the epoxide in 80–90 % yield after 24 h. Complexes 4–6 were superior to complexes 1–3. Complex 5 was the most‐active MoII−NHC complex, thereby achieving the epoxide in quantitative yield after 6 h.