NHC‐stabilized Parent Arsanylalanes and ‐gallanes

The synthesis and characterization of the unprecedented compounds IDipp⋅E′H(2)AsH(2) (E′=Al, Ga; IDipp=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐ylidene) are reported, the first monomeric, parent representatives of an arsanylalane and arsanylgallane, respectively, stabilized only by a LB (LB=Lewis Base). They are prepared by a salt metathesis reaction of KAsH(2) with IDipp⋅E′H(2)Cl (E′=Al, Ga). The H(2)‐elimination pathway through the reaction of AsH(3) with IDipp⋅E′H(3) (E′=Al, Ga) was found to be a possible synthetic route with some disadvantages compared to the salt metathesis reaction. The corresponding organo‐substituted compounds IDipp⋅GaH(2)AsPh(2) (1) and IDipp⋅AlH(2)AsPh(2) (2) were obtained by the reaction of KAsPh(2) with IDipp⋅E′H(2)Cl (E′=Al, Ga). The novel branched parent compounds IDipp⋅E′H(EH(2))(2) (E′=Al, Ga; E=P, As) were synthesized by salt metathesis reactions starting from IDipp⋅E′HCl(2) (E′=Al, Ga). Supporting DFT computations give insight into the different synthetic pathways and the stability of the products.