Synthesis and structure of [Sb{(PriN)2CNHPri}{(Pr iN)2CNPri}]; a distorted trigonal-bipyramidal antimony(iii) complex with a helical hydrogen-bond network

1,2,3-Triisopropylguanidine [(Pr i NH) 2 CNPr i ], reacts with antimony tris(dimethylamide) [Sb(NMe 2 ) 3 ] to provide [Sb{(Pr i N) 2 CNHPr i }{(Pr i N) 2 CNPr i }] 1, a heavily distorted trigonal-bipyramidal complex in which the Sb is chelated by a [C(NPr i ) 3 ] 2- dianion and a [(Pr i N) 2 CNHPr i ] - monoanion; in the solid state the complexes form helices by N–H···N hydrogen bonding of the single proton.