Phosphatranes as unusual stabilizing structures for hypervalent phosphorus: 10-P-5 mono- and divalent cations

Five-Coordinate and Quasi-Five-Coordinate Phosphorus

“…The 3 Ψ chemical shift of this compound (-2.2 ppm) is upfield as expected, and 10 11 no P=0 stretching frequency is detected in its IR spectrum. We observed similar results for the reaction of prophosphatrane 12 with BF3 (6) as well as with the other Lewis acids shown in reactions 7-13 (6,7,79). Although no structural metrics could be determined for 13-19, reaction 14 gave a crystalline product 21 which was structured by X-ray means (7, 79) whereas reactions 15-17 (7) did not provide single crystals.…”

Hypervalent phosphorus compounds as ligands

“…A large upfield shift of the 31 P NMR resonance was observed for both complexes consistent with a five-coordinate phosphorus center (Tables 1 and 2). The 31 P NMR chemical shifts are comparable to those observed for phosphatranes produced from protonation or alkylation of the chalcogenide [8][9][10]. In addition, new 31 P-1 H and 31 P- 13 C NMR couplings to the NCH 2 groups were observed.…”

“…We began our search for hypervalent phosphorus ligands with the phosphate triesters 1 and 2 prepared by Verkade and coworkers (Scheme 1) [8][9][10]. These phosphate triesters are named "pro-phosphatranes" and form hypervalent phosphorus compounds upon formation of a P-N transannular bond to form "phosphatranes."…”

“…[Co(NH 3 ) 5 (CF 3 SO 3 )](CF 3 SO 3 ) 2 [14], AuI 3 (P(CH 2 -CH) 3 ) 3 [15], MeHg(NO) 3 [16], and the phosphatranes 1 and 2 [8][9][10] were prepared as reported previously.…”

The preparation and reactions of 1,6-diphosphatricyclo[4.4.4.0]tetradecanediium ditrifluoromethanesulfonate

“…We see no evidence in these reactions for dicationic addends such as compounds 14 and 15 observed by Verkade et a1. 13 In fact, the 13C NMR spectra of the Fand MeO-adducts are broadened in a way that suggests that addition of these species to the dication may be reversible. Reduction of 10 with NaBH4 gives 16, which is formally the monoprotonated ion of diphosphine 1 (Scheme 3).…”