Synthesis of Cationic R2P5+ Cages and Subsequent Chalcogenation Reactions

Cationic R2P5(+) cage compounds (1(+)) have been synthesized by the stoichiometric reaction of R2PCl, GaCl3 and P4. The reaction conditions depend on the substituent R. Alkyl-substituted derivatives (1 a-1 d[GaCl4]) are best synthesized under solvent-free conditions, whereas aryl-substituted derivatives (1 e-1 h[GaCl4]) are formed in C6H5F. All compounds have been prepared on a multi-gram scale in good to excellent yields and have been fully characterized with an emphasis on (31P NMR spectroscopy in solution and single-crystal structure determination. Subsequent chalcogenation reactions of cations R2P5(+) (1 a(+), 1 e(+)) and trication Ph6P7(3+) (3(3+)) with elemental sulfur (α-S8) or grey selenium (Se(grey)) yielded a series of unique polyphosphorus-chalcogen cations (4 a(+), 4 e(+), 5 a(+), 6(2+) and 7(2+)), possessing nortricyclane-type molecular structures. An in-depth study of the (31)P{(1)H} and (77)Se NMR spectroscopic parameters is presented, and correlations between the substitution pattern and the observed structural features have been investigated in detail.