NHC-Stabilised Parent Tripentelyltrielanes

Abstract

A missing family of the extremely air sensitive tripentelyltrielanes was discovered. Their stabilisation was achieved by using the bulky NHC IDipp (NHC=N-heterocyclic carbene, IDipp=1,3-bis(2,6-diisopropylphenyl)-imidazolin-2-ylidene). The tripentelylgallanes and tripentelylalanes IDipp ⋅ Ga(PH2)3 (1 a), IDipp ⋅ Ga(AsH2)3 (1 b), IDipp ⋅ Al(PH2)3 (2 a) and IDipp ⋅ Al(AsH2)3 (2 b) were synthesised by salt metathesis of IDipp ⋅ ECl3 (E=Al, Ga, In) with alkali metal pnictogenides such as NaPH2/LiPH2 ⋅ DME and KAsH2, respectively. Moreover, the detection of the first NHC-stabilised tripentelylindiumane IDipp ⋅ In(PH2)3 (3) was possible by multinuclear NMR spectroscopy. Initial investigations of the coordination ability of these compounds resulted in the successful isolation of the coordination compound [IDipp ⋅ Ga(PH2)2(μ3-PH2{HgC6F4}3)] (4) by reaction of 1 a with (HgC6F4)3. The compounds were characterised by multinuclear NMR spectroscopy as well as single crystal X-ray diffraction studies. Supporting computational studies highlight the electronic features of the products.