Synthesis and characterization of Group 13 hydrides and metal-metal bondeddimers stabilized by the macrocyclic bis(amidophosphine) ligand [P2N2] ([P2N2] = [PhP(CH2SiMe2NSiMe2CH2)2PPh])
Md. Fryzuk et al., Synthesis and characterization of Group 13 hydrides and metal-metal bondeddimers stabilized by the macrocyclic bis(amidophosphine) ligand [P2N2] ([P2N2] = [PhP(CH2SiMe2NSiMe2CH2)2PPh]), J ORGMET CH, 591(1-2), 1999, pp. 63-70
Addition of LiAlH4 to the monomeric chlorides syn-MCl[P2N2] (M = Al (1), Ga
(2), In (3)) results in the formation of the aluminum hydride syn-AlH[P2N2
] (4). The solution H-1- and P-31{H-1}-NMR spectra are consistent with a C-
20 symmetric species in solution. The X-ray crystal structure shows the hyd
ride to be monomeric, and free from interaction with either salt (LiCl) or
external base (Et2O). The coordination of both phosphines of the macrocycle
to the metal center is found in the solid state. Solution molecular weight
measurements are consistent with a monomeric structure. The gallium hydrid
e syn-GaH[P2N2] (5) is synthesized by the addition of LiGaH4 to syn-MCl[P2N
2] (M = Ga (2), In (3)). This species is unstable and could only be charact
erized in solution. Reduction of syn-MCl[P2N2] (M = Ga (2), In (3)) with KC
8 yields the reduced, dimeric species {syn-M[P2N2]}(2) (M = Ga (6), In (7))
. The solution H-1- and P-31{H-1}-NMR spectra are consistent with C-2v symm
etric species in solution. The X-ray crystal structures of the gallium and
indium complexes confirm the presence of unsupported metal-metal bonds in b
oth cases. The features of the solution H-1- and P-31{H-1}-NMR spectra sugg
est that both dimers are fluxional in solution. (C) 1999 Elsevier Science S
.A. All rights reserved.