The tungsten-tungsten triple bond. 8. Dinuclear alkoxides of tungsten(III) and structural characterization of hexaisopropoxybis(pyridine)ditungsten, the first compound with four-coordinated tungsten atoms united by a triple bond

Metal-metal bonds and metal-carbon bonds in the chemistry of molybdenum and tungsten alkoxides

“…6 2 The structure of the W(OBut)3(NO)(py) 6 3 molecule is shown in Figure 19. Again, the local trigonal bipyramidal geometry is seen and extensive W(dxz dyz)4-to-NO * bonding is evident from the extremely short For molybdenum, the overall reaction proceeds according to 9 Also, CO dissociation from Mo 2 (OR) 6 (p-CO) is blocked when the dimer is ligated.…”

“…There can be little, if any, doubt that the other alkoxides of formula Mo 2 (OR) 6 Rather interestingly, alcoholysis reactions involving W 2 (NMe 2 ) 6 8 do not lead to an extensive series of compounds of formula W 2 (OR) 6 . 9 Only W 2 (OBut) 6 has been isolated, though amine adducts W 2 (OR) 6 (HNMe2) 2 have been i t 10 obtained for R = Pr and CH 2 Bu . Tungsten appears to differ from molybdenum in three important respects with regard to the formation and stability of M2(OR) 6 compounds.…”

“…Both of these points will be elaborated upon further in this article. (3) Whereas Mo 2 (OR) 6 compounds readily sublime when heated in vacuo, W 2 (OBut) 6 and the i t amine adducts W2(OR)6(HNMe2) 2 9 where R =Sie 3 , Pr and CH 2Bu , decompose when heated in vacuo above 80°C. 9 In the mass spectrometer, however, W (OR)6 + ions are observed.…”

“…(3) Whereas Mo 2 (OR) 6 compounds readily sublime when heated in vacuo, W 2 (OBut) 6 and the i t amine adducts W2(OR)6(HNMe2) 2 9 where R =Sie 3 , Pr and CH 2Bu , decompose when heated in vacuo above 80°C. 9 In the mass spectrometer, however, W (OR)6 + ions are observed. The most striking feature of the aforementioned compounds of formula M 2 (OR) 6 and M 2 X n(OR) 6-n is the presence of the M-M triple bond, unsupported by bridging alkoxide ligands.…”

The tetradecaisopropoxydihydridotetratungsten story

“…The hydride resonance appears as a singlet at 6 = 7.87 ppm, flanked by satellites of roughly one fifth intensity due to coupling two tungsten -183 nuclei (' 1 3 W, I = *, 14.4% natural abundance), J183W.,H 96 Hz. W 4 (p-H) 2 (OPri) 4 reacts with pyridine to form a Lewis base adduct or solvent compound W2(M-H)(OPri) 7 (py)x , but does not eliminate PrioH to give the known compound W2(OPri )(py)2.…”