Synthesis and crystal structures of [Ph3PCH2PPh3]I2 di-chloro-methane disolvate and [Ph3PCH2PPh3](BI4)2.

Abstract

Reaction of BI3 with carbodi-phospho-rane, C(PPh3)2, gives a mixture of the dicationic compounds, methyl-enebis(tri-phenyl-phospho-nium) diiodide di-chloro-methane disolvate, C37H32P22+·2I-·2CH2Cl2 or [Ph3PCH2PPh3]I2·2CH2Cl2 (I), methyl-enebis(tri-phenyl-phospho-nium) bis-(tetra-iodo-borate), C37H32P22+·2BI4- or [Ph3PCH2PPh3](BI4)2 (II). Solvents are the source of the protons at the ylidic C atom. The P-C-P angle is 124.1 (2)° for (I) and 121.7 (3)° for (II), while the two P-C bond lengths are 1.804 (4) and 1.807 (5) Å in (I), and 1.817 (5) and 1.829 (5) Å in (II). In the crystal of (I), the protons of the central P-CH2-P C atom exhibit weak C-H⋯I hydrogen bonds with the respective anions. The anions in turn are linked to the di-chloro-methane solvent mol-ecules by C-H⋯I hydrogen bonds. In the crystal of (II), one of the BI4- anions is linked to a phenyl H atom via a weak C-H⋯I hydrogen bond.