STUDIES OF CIS-[PTCL2(PPH2NPR)(BZS(O)BZ)] BY SOLID-STATE CP MAS P-31 NMR-SPECTROSCOPY, SINGLE-CRYSTAL X-RAY-DIFFRACTION AND X-RAY-POWDER DIFFRACTION - INVESTIGATION OF A QUESTION CONCERNING POLYMORPHISM VERSUS SPACE GROUP AMBIGUITY

The P-31 CP/MAS NMR spectrum of cis-[PtCl2(PPh2nPr)(BzS{O}Bz)] was found to exhibit two central resonances with appropriate couplings to Pt-195, despite the fact that a single-crystal x-ray diffraction study indicated that the complex crystallized in the monoclinic space group P2(1)/n with Z = 4, i.e. that there is only a single crystallographically unique phosphorus atom. The possibility that the 2(1) screw axis was absent (i.e. that the space group was actually Pn) was examined by a reinvestigation of the original x-ray data, but no definitive evidence for the alternative space group could be obtained. An examination of a bulk sample of cis-[PtCl2(PPh2nPr)(BzS{O}Bz)] by x-ray powder diffraction and comparison of the results with data from the single-crystal x-ray diffraction experiment revealed that the crystal selected for diffraction studies was a different polymorph from the bulk of the sample which was used for the P-31 CP/MAS NMR measurements. X-ray powder diffraction is thus shown to provide a valuable bridge between solid-state CP/MAS NMR measurements and single-crystal x-ray diffraction data.