Remote Substituent Effects on the Structures and Stabilities of PE π‑Stabilized Diphosphatetrylenes (R2P)2E (E = Ge, Sn)

• Published in: Inorganic chemistry Vol. 55; no. 20; pp. 10510 - 10522
• Main Authors: Izod, Keith, Evans, Peter, Waddell, Paul G., Probert, Michael R.
• Format: Journal Article
• Language: English
• Published: American Chemical Society 17.10.2016
• ISSN: 0020-1669; 1520-510X; 1520-510X
• DOI: 10.1021/acs.inorgchem.6b01566

A rare P–E π interaction between the lone pair of a planar P center and the vacant p orbital at the Ge or Sn center provides efficient stabilization for P-substituted tetrylenes (R2P)2E (E = Ge, Sn) and enables isolation of the first example of a compound with a crystallographically authenticated PSn bond. Subtle changes in the electronic properties of the bulky aryl substituents in these compounds change the preference for planar versus pyramidal P centers in the solid state; however, variable-temperature NMR spectroscopy indicates that in solution these species are subject to a dynamic equilibrium, which interconverts the planar and pyramidal P centers. Consistent with this, density functional theory studies suggest that there is only a small energy difference between the planar and pyramidal forms of these compounds and reveal a small singlet–triplet energy separation, suggesting potentially interesting reactivities.