Attempts to prepare W2(?-diketonate)4(M4-M) complexes by reductiye elimination fromd 3 -d 3 ditungsten complexes. Preparation and structures of W2 R 2(NMe2)2 (Bu t -acac)2 and W2 R 2(OPr i )2 (Bu t -acac)2 compounds, whereR = Et, Ph, CH2Ph, and BC i

Abstract

The reactions between 1,2-W2R2(NMe2)4 (R=Et and Ph) and 1,2-W2R2(OPri)4 (R=CH2Ph and But) and But-CHCOCH2COBut (But-acacH) (4 equiv)in pentane or hexane give, respectively, W2R2NMe2)2 (But-acac)2 and W2R2(OPri)2 (But-acac)2 that are remarkably thermally and photochemically robust with respect to further reaction and reductive elimination to give the targeted compounds W2(But-acac)4. The new compounds have been characterized by elemental analysis, infrared, and1H NMR spectroscopy and forR = Et and CH2Ph by single crystal X-ray studies. In each compound there are four coordinate W atoms united by unbridged W-W triple bonds. Crystal data for W2Et2(NMe2)2 (But-acac)2 at −165°C:a=17.115(2) A,b=10.542(1) A,c = 19.786(3) A.β = 98.55(1)°,Z = 4, and space group C2/c; for W2(CH2Ph)2 (OPri)2 (But-acac)2 at −157°C:a=23.547(5) A,b = 10.784(2)A,c = 21.105(5) A,β = 127.20(1)°,Z = 4, and space group C2/c.