화학공학소재연구정보센터
Inorganic Chemistry, Vol.44, No.22, 8135-8144, 2005
Synthesis of nickel-monocarbollide complexes by oxidative insertion
Treatment of the 11-vertex carborane anion [closo-2-CB10H11](-) with Ni(O) reagents in tetrahydrofuran (THF) affords(-) via oxidative insertion reactions-12-vertex Ni(II) complexes, isolated as the salts [N(PPh3)(2)][2,2-L-2-closo-2,1-NiCB10H11] (L = CO (1a), CNBut (1b), and CNXyl (1C; Xyl = C6H3Me2-2,6); L-2 = cod (1d; cod = 1,2:5,6-77-cyclo-octa-1,5diene)). One CO ligand in la is readily replaced by donors L' in the presence of Me3NO to give the species [N(pph(3))(2)][2-CO-2-L'-closo-2,1-NiCB10H11] (L' = PEt3 (1e), PPh3 (1f), CNBut (1g), and CNXyl (1h)). The anionic complexes themselves readily react with hydride abstracting reagents in the presence of donor ligands to yield zwitterionic complexes in which boron vertexes bear substituents that are bound through C, N, or 0 atoms. Thus, for example, 1c with H+ and CNXyl gives [2,2,7-(CNXyl)(3)-closo-2,1-NiCB10H10] (2b), while 1f with Me+ in the presence of OEt2 affords [2-CO-2,11-{mu-PPh2(C6H4-o)}-7-OEt2-closo-2,1-NiCB10H9] (4), in which an additional cycloboronation of one phosphine phenyl ring has occurred. In contrast, If with Me+ in the presence of NCMe gives a mixture of the isomers [2-CO-2-PPh3-7-{(X)-N(Me)=C(H)Me}-closo-2,1-NiCB10H10] (X &3bond; E(5c) and Z(5d)). X-ray diffraction analyses of compounds la, 2b, 4, and 5c confirmed their important structural features.