Derivatives of substituted 3-trichlorogermyl propionic acid

Abstract

In the course of systematic structural studies of dicitratoborates the investigation of the crystal structure of NH2CSHNH2[(C6H6O7)2B] has been carried out. The dicitratoborate complex with thiourea (L) was synthesized according to [1]. The structure is formed by cations of thiourea (HL) + and spiran-type complex anions [(C6H6O7)2B] -. In the complex anions two citric acid resides are coordinated bidentatically to the BO4-terahedron. The values of the chemical bond lengths and bond angles in the complex anions are in accordance with those determined earlier for the crystal structures of dicitratoborates. The boron-containing five-membered rings are approximately planar. The cation (NH2CSHNH2) + is protonated at the sulphur atom. The protonation gives rise to delocalization of p-electron density at the C-S and N-C bonds. The bond lengths are: C-S 1.738(2) Å; N-C 1.317(3) Å and 1.298(3) Å. The bond C(sp 2 )-S is lengthened for 0.10 Å, but the C(sp 2 )-N bonds are shortened for 0.04 Å in average in the cation (HL) + when compared with the neutral molecule (L). In the crystals each organic cation is bonded with three nonidentical complex anions by five hydrogen bonds N-H … O (2+2) and S-H … O. The complex anions are bonded directly by four strong hydrogen bonds O-H … O (length from 2.589 to 2.692 Å).