Complexes of cobalt(II) with α-diimines. The crystal structure of CoCl2(t-BuNCHCHNt-Bu)

Synthesis of cobalt(II)-α-diimines complexes and their activity as mediators in organometallic mediated radical polymerization of vinyl acetate

“…The bands in the region of 300-345 cm À1 are assigned to m(CoACl) stretching vibrations. This assignment is quite reasonable and in agreement with previous assignments for related tetrahedral complexes [16][17][18][19].…”

“…The bands at higher energy arise from n-p ⁄ transitions and are associated with the azomethine chromophore, whereas the bands at lower energy are attributable to p-p ⁄ transitions within the phenyl rings [35]. All compounds display an intense band at approximately 230 nm; this excitation is attributed to the p-p ⁄ transitions arising from the azomethine group [16,17].…”

“…These ligands are bidentate, very rigid, and can easily have their backbone changed to modify the electronic and steric effects at the metal centre [16][17][18][19][20]. Moreover, diazabutadiene (or a-diimine)…”

Ligand and solvent effects on cobalt(I)-catalysed reactions: Alkyne dimerisation versus [2+2+2]-cyclotrimerisation versus Diels–Alder reaction versus [4+2+2]-cycloaddition

“…The complexes were synthesised by suspending anhydrous CoBr 2 (2.18 g, 10.0 mmol) and the ligand (10.0 mmol) in anhydrous THF (40 mL) at room temperature [17]. After stirring overnight the solvent was removed in vacuo and the solid product was used without further purification.…”

“…(1Z,3Z,6Z)-6-Methyl-2,3-diphenyl-cycloocta-1,3,6-trien ( 1, 140.6, 138.9, 135.1, 128.4, 127.1, 127.0, 126.8, 126.7, 123.9, 123.4, 120.2, 34.0, 28.3, 27 (14), 178 (17), 165 (23), 115 (19), 91 (17). HRMS calculated for C 21 H 20 : m/z=272.1565, found: m/z = 272.1559.…”