Gallaphosphene L(Cl)GaPGaL: A novel phosphinidene transfer reagent.

Gallaphosphene L(Cl)GaPGaL 1 (L=HC[C(Me)N(Ar)] 2 ; Ar=2,6-iPr 2 C 6 H 3 ) reacts with N-heterocyclic carbenes R NHC ( R NHC=[CMeN(R)] 2 C; R=Me, iPr) to R NHC-coordinated phosphinidenes R NHC→PGa(Cl)L (R=Me 2 a, iPr 2 b) and with isonitriles RNC (R=iPr, Cy) to 1,3-phosphaazaallenes L(Cl)GaP=C=N-R (R=iPr 3 a, Cy 3 b), respectively. Quantum chemical calculations reveal that 2 a/2 b possess two localized lone pair of electrons, whereas 3 a/3 b only show one localized lone pair as was reported for gallaphosphene 1. 2 b reacts with 2.5 equivalents of a borane (THF ⋅ BH 3 ) to the NHC-stabilized phosphinidene-borane complex [ iPr NHC→P(BH 2 )] 2 (BH 3 ) 3 4 with concomitant formation of LGa(H)Cl 5. 2-5 are characterized by heteronuclear ( 1 H, 13 C{ 1 H}, 31 P{ 1 H}) NMR and IR spectroscopy, elemental analysis, and single crystal X-ray diffraction (sc-XRD).