名称:
Zinc, Cadmium, and Mercury Metallocenes Incorporating 1,2-Diaza-3,5-diborolyl Ligands
摘要:
Sandwich compounds incorporating 1,2-diaza-3,5-diborolidine ligands have been prepared by metathesis reactions between zinc, cadmium, and mercury dihalides and M[cyclo-MeC(BR)(2)(NiPr)(2)] (M = Li, K; R = Me, Ph). The metallocenes M[cyclo-MeC(BR)(2)(NiPr)(2))](2) (M = Zn, R = Me (2a), Ph (2b); M = Cd, R = Me (3a), Ph (3b); M = Hg, R = Me (4a)) have been isolated and characterized by multinuclear NMR and mass spectrometry. The molecular structures of complexes 2a,b, 3a center dot BrLi(THF)(3), 3b, and 4a were determined by single-crystal X-ray diffraction and displayed strong similarities to the structures of their cyclopentadienyl analogues. All molecules are monomeric in the solid state, containing nearly parallel ligands featuring an eta(3) coordination mode in 2a and eta(1) coordination modes in the remaining complexes. Spectroscopic evidence indicates that the solid-state structure is maintained in solution and that Lewis basic solvents have the ability to coordinate reversibly to the metal centers. For comparison, the sigma-bonded analogues [cyclo-MeC(BR)(2)(NiPr)(2)]SiCl3 (R = Me (5a), Ph (5b)) were prepared, and the structure of 5b was determined using single-crystal X-ray diffractometry.