Structural study on quasi‐phosphonium salts containing phosphorus–oxygen, phosphorus–oxygen, phosphorus–nitrogen and phosphorus‐sulphur bonds

Abstract

The crystal and molecular structures of six quasi-phosphonium salts containing phosphorus-heteroatom (heteroatom = oxygen, sulphur or nitrogen) bonds were determined. Comparison of the molecular parameters obtained with those available for reference structures demonstrated that the 'double bond' character for the P'-Y bond decreases in the order Y = N w 0 > S.

Oxophosphonium-alkyne cycloaddition reactions: reversible formation of 1,2-oxaphosphetes and six-membered phosphorus heterocycles

“…The C1–C2 bond (1.314 Å) and the C2–O bond (1.413 Å) are in the range of typical CC double and C–O single bonds, respectively. The P–O bond of 1.677 Å is considerably elongated compared to the similarly substituted phosphine oxide t Bu­( i PrHN) 2 PO (1.489 Å) and to the acyclic phosphonium salt [Me­(Me 2 N) 2 ­POCH 2 t Bu]­[I] (1.546 Å), which indicates a rather weak P–O bond in [ 2a ] + . The cycloaddition reaction between [ 1 ]­[OTf] and phenylacetylene is less selective (cf.…”

(Isopropylamino)(methyl)diphenylphosphonium iodide

“…Amidophosphonium salts are useful precursors for phosphazenes, which are necessary for the aza-Wittig reaction. They can be synthesized by different methods: addition of alkylhalides or methyltriflate to a phosphorus-nitrogen-single bond (Payne et al, 1965;Mizuta et al, 2007), addition of alkylhalides to a phosphorus-nitrogen double bond (Imrie et al, 1995), via intramolecular addition of alkylhalides (Aladzheva et al, 2003) or via other routes (Demange et al, 2006). We became interested in this class of compounds, because the starting compound Ph 2 PN( i Pr)P(Ph)N( i Pr)H acts as a superb ligand in the chromium catalyzed trimerization of ethene (Peitz et al, 2010).…”

“…For the synthesis of Ph 2 PN( i Pr)P(Ph)N( i Pr)H, see: Peitz et al (2010). For the structures of amidophosphonium salts with similar substituents, see: Payne et al (1965); Imrie et al (1995); Aladzheva et al (2003); Demange et al (2006); Mizuta et al (2007). Table 1 Hydrogen-bond geometry (Å , ).…”

Tetrahydropentalenyl-phosphazene constrained geometry complexes of rare-earth metal alkyls

“…652(2) Å is rather long. This can be better compared with the values found in phosphonium salts [Ph 3 P-NH(iso-Pr)]-Br (P-N = 1.621(3) Å) 27. The C-C bonds of the Cp ring of L Ad H are conjugated (average bond length d(C-C) = 1.41 Å, maximum C-C bond difference d = 0.07 Å).…”