THE USE OF SILYLETHERS AND SILYLTHIOETHERS IN SYNTHESES OF OXOHALIDE AND THIOHALIDE COMPOUNDS OF MOLYBDENUM AND TUNGSTEN

Convenient procedures for the preparation of molybdenum and tungsten oxo- and thiohalides are described which exploit reactions between transition metal halides and bis(silyl)ether and -thioether reagents, according to the general equation: MCIx+(Me3Si)2Y (Y = O,S)→M(Y)Clx-2+2Me3SiCl. W(O)Cl4 (1) and Mo(O)Cl3 (5) are formed in high yield by room temperature treatment of WCl6 and MoCl5 with (Me3Si)2O in CH2Cl2 solvent. Mo(O)2Cl2 (6) may be obtained from Mo(O)Cl4 by an analogous room temperature procedure; efficient generation of W(O)2Cl2 (2) requires warming of W(O)Cl4 with (Me3Si)2O at 80°C in octane. In acetonitrile solvent, W(O)Cl4 reacts with one equivalent of (Me3Si)2O to give W(O)2Cl2(CH3CN)2 (3) in 70% yield. Treatment of W(O)Cl4 with two equivalents of (Me3Si)2O in CH2Cl2 leads to blue crystalline W(O)2Cl(OSiMe3) (4), which is stable to elimination of Me3SiCl to 1OO°C. W(S)Cl4 (7), W(S)2Cl2 (8) and Mo(S)Cl3 (9) are obtained by low temperature treatment of WCl6, W(S)Cl4 and MoCl5, respectively, with one equivalent of (Me3Si)2S in CH2Cl2 solvent. The mixed oxothiohalide compounds W(O)(S)Cl2 (10) and Mo(O)(S)Cl2 (11) may be isolated in good yield through the reaction of W(O)Cl4 or Mo(O)Cl4 with (Me3Si)2S in CH2Cl2 at low temperature. © 1990.