Dinuclear niobium(III) and tantalum(III) complexes with thioether and selenoether ligands [{MIIIX2(L)}2(μ-X)2(μ-L)] (M = Nb, Ta; X = Cl, Br; L = R2S, R2Se): Syntheses, structures, and the optimal conditions and the mechanism of the catalysis for regioselective cyclotrimerization of alkynes
作者:Masatoshi Matsuura、Takashi Fujihara、Masaki Kakeya、Tomoaki Sugaya、Akira Nagasawa
DOI:10.1016/j.jorganchem.2013.07.035
日期:2013.11
catalytic activity. The niobium(III) chloride complexes with selenoether (L = dimethyl selenide (Me2Se), tetrahydroselenophene (C4H8Se, THSe, selenolane) have higher rates for the reaction with alkynes, but low activity for the cyclotrimerization. Tantalum(III) chloride complexes (L = Me2S, THT, tetrahydrothiopyran (C5H10S, THTP, thiane)) have lower catalytic activities than the niobium(III) ones, because
一系列具有硫属元素供体[M III X 2(L)} 2(μ-X)2(μ-L)]的双核卤化铌(III)和钽(III)络合物(M = Nb; X = Cl, Br; L = R 2 S,R 2 Se)(M = Ta; X = Cl,Br; L = R 2 S)已通过二金属(V)十卤化物(M 2 X 10)和镁和L。通过X射线晶体学测定,其中五个新配合物的结构具有MM双键。事实证明,溶剂和温度在实现炔烃的环三聚化的高产率和区域选择性中起重要作用。氯化铌(III)配合物(L =二甲基硫醚(Me 2 S),四氢噻吩(C 4 H 8 S,THT,噻吩)在室温下在甲苯中与苯乙炔反应,得到了首尾相接的三环三聚体炔,1,3,5- (Ph)3 -2,4,6-(H)3-苯和头对头环加成的1,2,4-(Ph)3 -3,5,6- (高)3-苯,收率高。硫醚配体越小,催化活性越高。氯化铌与硒醚(L =二甲基硒化物(Me