The synthesis and characterization for trifluoromethanesulfonate (triflate) salts of the first definitive examples of cyclotriphosphinophosphonium and cyclodiphosphinophosphonium cations are described, representing new prototypical frameworks in the rational and systematic development of catena-phosphorus chemistry. Addition of methyl triflate (MeOTf) or triflic acid (HOTf) to cyclotetraphosphines (tBuP)4 (1a) or (CyP)4 (1b) gives [(tBuP)3PtBuMe][OTf] (2a[OTf]), [(CyP)3PCyMe][OTf] (2b[OTf]), [(tBuP)3PtBuH][OTf] (3a[OTf]), and [(CyP)3PCyH][OTf] (3b[OTf]), respectively. Cyclotriphosphine (tBuP)3 (4a) reacts with HOTF or Me2PCl/Me3SiOTf to give the ring expanded cations 3a[OTf] and [(tBuP)3PMe2][OTf] (5[OTf]), respectively, but reactions with MeOTf and HCl give cyclic diphosphinophosphonium cation [(tBuP)2PtBuMe][OTf] (6a[OTf]) and ring-opened triphosphine HtBuP-PtBu-PtBuCl (7), respectively. The analogous diphosphinophosphonium cation [(CyP)2PCyMe][OTf] (6b[OTf]) is formed along with 2b[OTf] in reactions of MeOTf with (CyP)3 (4b). Compounds 2a[OTf], 2b[OTf], 3a[OTf], 5[OTf], and 6a[OTf] have been crystallographically characterized. 1H NMR spectra of 2a[OTf], 2b[OTf], 5[OTf], and 6a[OTf] demonstrate that 3JPH coupling is only observed for methyl protons if they are in a cis orientation to the lone pairs on the adjacent phosphine sites.
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Chem Sci
April 2016
Department of Chemistry , University of Victoria, P.O. Box 3065, Stn CSC , Victoria , BC V8W 3V6 , Canada . Email: ; Email: ; ; Tel: +1 250-721-7150 ; Tel: +1 250-721-7181.
A series of phosphinophosphonium cations ([RPPMe]; R = Me, Et, Pr, Bu, Cy, Ph and N Pr) have been prepared and examined by collision-induced dissociation (CID) to determine the fragmentation pathways accessible to these prototypical -phosphorus cations in the gas-phase. Experimental evidence for fission of P-P and P-E (E = P, C) bonds, and β-hydride elimination has been obtained. Comparison of appearance potentials for the P-P bond dissociation fragments [RP] (P-P heterolysis) and [PMe]˙ (P-P homolysis) shows that heterolytic P-P cleavage is more sensitive than P-P homolysis towards changes in substitution at the trivalent phosphorus center.
View Article and Find Full Text PDFInorg Chem
September 2015
Chemical Faculty, Department of Inorganic Chemistry, Gdansk University of Technology, G. Narutowicza St. 11/12, Pl-80-233 Gdansk, Poland.
The reactivity of an anionic phosphanylphosphinidene complex of tungsten(VI), [(2,6-i-Pr2C6H3N)2(Cl)W(η(2)-t-Bu2P═P)]Li·3DME toward PMe3, halogenophosphines, and iodine was investigated. Reaction of the starting complex with Me3P led to formation of a new neutral phosphanylphosphinidene complex, [(2,6-i-Pr2C6H3N)2(Me3P)W(η(2)-t-Bu2P═P)]. Reactions with halogenophosphines yielded new catena-phosphorus complexes.
View Article and Find Full Text PDFJ Am Chem Soc
October 2014
Department of Chemistry, University of Victoria, Victoria, British Columbia V8W 3V6, Canada.
The cyclo-diphosphinophosphonium salt [(PtBu)3Me][OTf] (2) has been shown to be highly reactive toward Lewis bases, exhibiting diverse reactivity with phosphines, 4-(dimethylamino)pyridine (dmap) and chlorophosphines, providing approaches to new open-chain and cyclic catena-phosphorus frameworks. Reaction of 2 with R3P (R = Me or nPr) or dmap led to the ring-opened adducts [R3P-PtBu-PtBu-P(Me)tBu][OTf] (R = Me (4a), nPr (4b)) and [(dmap)-PtBu-PtBu-P(Me)tBu][OTf] (6), respectively. The complicated (31)P{(1)H} NMR spectra of the three compounds were simulated, evidencing the presence of two diastereomeric forms of 4a, and single diastereomers of 4b and 6.
View Article and Find Full Text PDFInorg Chem
April 2011
Department of Chemistry, Dalhousie University, Halifax, NS, B3H 4J3, Canada.
New examples of chlorophosphinochlorophosphonium (4) and chlorophosphinodichlorophosphonium (5) cations have been prepared and spectroscopically characterized. These bifunctional phosphinophosphonium cations offer a new approach to the development of phosphinophosphonium frameworks using reductive coupling reactions and have been exploited as synthons to assemble larger catena-phosphorus cations. The reactions of 4 and 5 with stibine reducing agents have been studied using (31)P NMR spectroscopy and have been shown to produce a variety of new and known frameworks in a facile manner, depending on the reducing agent selection and the stoichiometry of the reaction.
View Article and Find Full Text PDFJ Am Chem Soc
December 2009
Department of Inorganic and Analytical Chemistry, Westfälische Wilhelms-University Münster, Germany.
Chlorination of 1,2,3,4-tetracyclohexyl-cyclo-tetraphosphine (2) by PhICl(2) or PCl(5) in the presence of Me(3)SiOTf or GaCl(3) provides a stepwise approach to salts of the first cyclo-phosphino-chlorophosphonium cations [Cy(4)P(4)Cl](+) ([19](+)) and [Cy(4)P(4)Cl(2)](2+) ([20](2+)). The analogous iodo derivative [Cy(4)P(4)I](+) ([17](+)) is obtained as the tetraiodogallate salt from reaction of 2 with I(2) in the presence of GaI(3). Reactions of the dication [20](2+) with PMe(3) or dmpe effect a dissociation of the cyclic framework resulting in the formation of salts containing [Me(3)PPCyPCyPMe(3)](2+) ([27](2+)), [dmpeCyP](2+) ([29](2+)), and [dmpeCyPCyP](2+) ([30](2+)), respectively.
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