Bidentate Phosphanyl‐ and Arsanylboranes

A new class of neutral bidentate ligands with pnictogenyl‐functional sites has been obtained. The reaction of tmeda⋅(BH 2 I) 2 ( 1 , tmeda=tetramethylethylendiamine) with different phosphanides yields the corresponding bidentate phosphanylboranes tmeda⋅(BH 2 PH 2 ) 2 ( 2 a ), tmeda⋅(BH 2 PPh 2 ) 2 ( 2 b ), and tmeda⋅(BH 2 t BuPH) 2 ( 2 c ). This reaction strategy could be further extended to synthesize the first bidentate arsanylborane tmeda⋅(BH 2 AsPh 2 ) 2 ( 3 ). Depending on the substituents on the phosphorus, these compounds form different Au I complexes, to build either polymeric tmeda⋅(BH 2 PH 2 AuCl) 2 ( 4 a ), or monomeric tmeda⋅(BH 2 PPh 2 AuCl) 2 ( 4 b ) products. These compounds form also neutral oligomeric group 13/15 chain‐like molecules by coordination to a boron moiety such as tmeda⋅(BH 2 PH 2 BH 3 ) 2 ( 5 a ) and tmeda⋅(BH 2 AsPh 2 BH 3 ) 2 ( 5 b ). DFT calculations provide insight into the differences between the syntheses of mono‐ and bidentate pnictogenylboranes.