Azaborolinyl-Komplexe, XII [1] Gemischte η4 -1.2-Azaborolin-η5-cyclopentadienyl- und η5-1.2-Azaborolinyl-η5-cyclopentadienyl-Cobalt-Sandwich-Komplexe / Azaborolinyl Complexes, XII [1] Mixed η4-1,2-Azaboroline-η5-cyclopentadienyl-, and η5 -1,2-Azaborolinyl-η5-cyclopentadienyl Cobalt Sandwich Complexes

Abstract

Abstract Neutral 1-tert-butyl-2-methyl-Δ3-1,2-azaboroline and 2-methyl-1-trimethylsilyl-Δ3-1,2- azaboroline act as 4π electron donors in the mixed sandwich complexes 1-tert-butyl-2-methyl-η4-1,2-azaboroline-η5-cyclopentadienyl cobalt (1) and 2-methyl-1-trimethylsilyl-η4-1,2-azaboroline-η5-cyclopentadienyl cobalt (2), respectively. They are formed by the reaction of (C5H5)Co(C2H4)2 with the free ligands without any solvent and are isolated as green oily liquids. 1 and 2 can be transformed into mixed sandwich complexes with η5-1,2- azaborolinyl ring ligands by loss of a hydrogen atom of the CH2 group. This occurs at room temperature to give 1-tert-butyl-2-methyl-η5-1,2-azaborolinyl-η5-cyclopentadienyl cobalt (3) and 2-methyl-1-trimethylsilyl-η5-1,2-azaborolmyl-η5-cyclopentadienyl cobalt (4) in low yields. Mass, 1H, and 11B NMR spectra are discussed.