Two monomeric, octahedral complexes of alkaline earth metal salts: syntheses, physical characteristics, and crystal structures of Srl2·4HMPA and Sr(NCS)2·4HMPA [HMPA = O : P(NMe2)3

Abstract

The complexes (Srl2·4HMPA)n, (1), and [Sr(NCS)2·4HMPA]n, (2), [HMPA = O : P(NMe2)3], were synthesised by reactions of Sr metal, NH4X solids (X = I and SCN, respectively), and HMPA (1:2:4 molar amounts) in toluene, and several HMPA complexes of calcium and barium halide and thiocyanate salts have been made by analogous routes; X-ray diffraction has shown that both Sr species have discrete molecular (n=1), octahedral structures, the X groups being trans in (1) but cis in (2).