For reactions between [M(NBut)2Cl2] (M = Cr or Mo) or [Mo(NAr)2Cl2]·dme, Ar = 2,6-Pri2C6H3, dme = 1,2-dimethoxyethane, and tetraphenyldisiloxanediol, [O(Ph2SiOH)2] (2∶1), in the presence of a nitrogen donor base, changing the nitrogen donor from pyridine, py, to triethylamine, NEt3, inhibited the protonation of imido groups and facilitated the formation of bis-imido compounds. Thus the compounds [Cr(NBut)2(O(Ph2SiO)2)]21, [Mo(NBut)2(O(Ph2SiO)2)2] 2 and [Mo(NAr)2(O(Ph2SiO)2)]23 were isolated when NEt3 was used as base. Compound 3 was also formed when the dilithium reagent [O(Ph2SiOLi)2] was used. The pyridine adduct [Mo(NAr)2Cl2]·2py 4 was isolated from the reaction between [Mo(NAr)2Cl2] and O(Ph2SiOH)2 and py (1∶1∶2 molar ratio). Compounds 2, 3·C6H6 and 4·0.5C6H5Me have been characterised by X-ray crystallography. The dimeric composition of 1 in the gas phase and in benzene was confirmed by mass spectroscopy and cryoscopic molecular weight determination respectively. All compounds were characterised by NMR spectroscopy.
对于 [M(NBut)2Cl2](M = Cr 或 Mo)或 [Mo(NAr)2Cl2]·dme、Ar = 2,6-Pri2C6H3、dme = 1,2-
二甲氧基乙烷和四苯基二
硅氧烷二醇之间的反应,[O( Ph2SiOH)2](2∶1)在氮供体碱存在下,将氮供体从
吡啶py改为
三乙胺NEt3,抑制亚
氨基的质子化,促进双亚
氨基化合物的形成。因此化合物 [Cr(NBut)2(O(Ph2SiO)2)]21、[Mo(NBut)2(O(Ph2SiO)2)2] 2 和 [Mo(NAr)2(O(Ph2SiO)2)]当使用NEt3作为碱时,分离出23个。当使用二
锂试剂[O(Ph2SiOLi)2]时也形成化合物3。由[Mo(NAr)2Cl2]与O(Ph2SiOH)2和py(摩尔比1∶1∶2)反应分离得到
吡啶加合物[Mo(NAr)2Cl2]·2py 4 。化合物2、3·
C6H6 和4·0.5C6H5Me 已通过X 射线晶体学进行了表征。分别通过质谱和低温分子量测定证实了气相中和苯中1的二聚体组成。所有化合物均通过核磁共振波谱进行表征。