The stabilization of monomeric parent compounds of phosphanyl- and arsanylboranes

The structures of the parent compounds of phosphanyl- and arsanylboranes, H(2)BPH(2) and H(2)BAsH(2), were calculated by DFT-B3LYP methods. Such compounds have not previously been obtained preparatively. By applying the concept of Lewis acid/base stabilisation, (CO)(5)W(H(2)EBH(2).NMe(3))] (E=P (3), As (4)) derivatives have been synthesised by the metathesis reactions between Li(CO)(5)WEH(2)] and ClH(2)BNMe(3) (E=P, As). Comprehensive thermodynamic studies on these systems verify the high stability of the Lewis acid/base stabilised complexes. Unexpected based on the thermodynamic calculations, UV radiation of the phosphanylborane 3 leads to the dinuclear phosphanido-bridged complex (CO)(8)W(2)(mu-PHBH(2).NMe(3))(2)] (5) by H(2) and CO elimination.