Non-order-disorder allotwinning of the rhenium pincer complex cis-Re[(PNP-iPr)(CO)Cl].

Crystals of cis-Re[(PNP-iPr)(CO)Cl] (1) are made up of two geometrically non-equivalent polytypes with respective symmetries of P2/c and I2/a. The structures were determined in a concurrent refinement, taking into account overlap of diffraction spots. The polytypes are composed of layers with p12/c1 symmetry and are of the non-order-disorder (OD) type (the layer interfaces are non-equivalent). Whereas the molecules of (1) differ in both polytypes, the Re atoms are located at nearly identical positions.