SYNTHESIS AND STRUCTURE OF PYRIDO[2,3-H]P YRROLO[1,2-A]QUINOXALINIUM TETRACHLOROPLATINATE(II) MONOHYDRATE, [C14H11N3][PTCL4].H2O

The structure of the title compound, 5H+,8H+-pyrido[2,3-h]pyrrolo[1,2- a]quinoxalinium tetrachloroplatinate monohydrate, consists of a square planar (PtCl4)2- anion and a PPQH22+ cation, where PPQH2+ is the prot onated organic ligand. The protonation on the N(5) and N(8) atoms give s rise to an opening of the angles C(4)-N(5)-C(14) and C(9)-N(8)-C(15) when compared with the homologous values in the neutral PPQ form. Alt hough each ring of the PPQH22+ ion is almost planar to within experime ntal error, the ion as a whole is not, as shown by the value of the di hedral angle [18.8 (2)-degrees] between the mean planes of the pyrrole (P1) and the pyridine (P4). A hydrogen bond between the water O atom and a PPQH22+ N atom exists.