Monophosphanes and disphosphanes with the hypersilyl substituent

• Published in: European journal of inorganic chemistry no. 22; pp. 4589 - 4599
• Main Authors: Cappello, Vittorio, Baumgartner, Judith, Dransfeld, Alk, Hassler, Karl
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 20.11.2006
• Subjects: Chemistry; Chemistry, Inorganic & Nuclear; Physical Sciences; Science & Technology; PHOSPHORUS; SILYLPHOSPHANES; PYRAMIDAL INVERSION; DEPENDENCE; ab initio calculations; silicon; hypersilylphosphanes; potassium phosphanides; MOLECULAR-STRUCTURES; CHEMISTRY; SPECTRA; DERIVATIVES; P-silylhalophosphanes
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.200600444

The synthesis of (SiMe3)(3)SiPH2 (1) (further on denoted as hypersilylphoshane, HypPH(2)) was achieved by two methods: by the reaction of (SiMe3)(3)Si(OSO2CF3) with PH3, and alternatively, by the reaction of Na PH2 with (SiMe3)(3)SiCl (hypersilylchloride). The latter reaction also affored bis(hypersilyi)phosphane Hyp(2)PH (2). By the reaction of 1 and known hypersilylbis(trimethylsily)phosphane (3) with tBuOK, the noval hypersilylphosphanides HypPHK (4) and Hpy(SiMe3)-PK (5) were prepared. Compound 1 also reacted with nBuLi to form HpyPHLi (6) and HypPLi(2) (7). Furthermore, 3 reacted with hexachloroethane and 1,2-dibromotetrachloethane to give HypPCl(SiMe3) (8) and HypPBr(SiMe3) (9) as well as HypHPPHHyp (12) as a mixture of the meso- and rac-D-L-diastereomers and Hyp(SiMe3)pp(SiMe3)Hyp (13) as the D,L-modification only. By reducing the known compound tBuHypPVl with potassium, D,L-modification of tBuHypPPHyptBu (14) was obtained. All compounds were charaacterized by Si-29- and P-31 NMR spectroscopy and elemental analyses with the exception of the phosphanides which were characterized specroscopically only. The crystal structures of 3 and 4 and of diphosphanes 10, 11 and 13 are reported. From temperature-dependent P-31 NMR experiments, the coalescence temperature for the meso -><- D,L interconversion of 12 was determined at 100 degrees C and gave an inversion barrier of roughly 69.4 kJ mol(-1), which is corroborated by results of ab initio calculations at the B3LYP/6-31G(d) level. Two diasteromeric inversion transition structures for P-H bond and the phosphorus lone pair of electrons could be located; bulky substituents seem to prefer the anti arrangement.