Self-assembly of a columnar polymeric calcium phosphinate derived from camphene

(2,2-Dimethylbicyclo[2.2.1] hept-3-ylmethyl)phosphinic acid (RPO₂H₂), readily prepared from camphene and hypophosphorous acid, formed a polymeric calcium salt [{Ca(RPO₂H) ₂ (RPO₂H₂)(H₂O)}n], with both terminal and triply bridging phosphinate groups, and an overall columnar structure with an inorganic core and a pseudo-close-packed sheath of terpene moieties

Platinum(II) phosphonate complexes derived from endo-8-camphanylphosphonic acid

The reactions of cis-[PtCl₂L₂] [L = PPh₃, PMe₂Ph or L₂ = Ph₂P(CH₂)₂PPh₂ (dppe)] with endo-8-camphanylphosphonic acid (CamPO₃H₂) and Ag₂O in refluxing dichloromethane gave platinum(II) phosphonate complexes [Pt(O₃PCam)L₂]. The X-ray crystal structure of [Pt(O₃PCam)(PPh₃)₂]•₂CHCl₃ shows that the bulky camphanyl group, rather than being directed away from the platinum, is instead directed into a pocket formed by the Pt and the two PPh₃ ligands. This allows the O₃P–CH₂ group to have a preferred staggered conformation. The complexes were studied in detail by NMR spectroscopy, which demonstrates non-fluxional behaviour for the sterically bulky PPh₃ and dppe derivatives, which contain inequivalent phosphine ligands in their ³¹P NMR spectra. These findings are backed up by theoretical calculations on the PPh₃ and PPhMe₂ derivatives, which show, respectively, high and low energy barriers to rotation of the camphanyl group in the PPh₃ and PPhMe₂ complexes. The X-ray crystal structure of CamPO₃H₂ is also reported, and consists of hydrogen-bonded hexameric aggregates, which assemble to form a columnar structure containing hydrophilic phosphonic acid channels surrounded by a sheath of bulky, hydrophobic camphanyl groups

Camphene-derived primary and hydroxymethyl phosphines

Thermal disproportionation of (2,2-dimethylbicyclo[2.2.1]hept-3-ylmethyl)phosphinic acid (endo-8-camphanylphosphinic acid, camPO₂H₂) yields the primary phosphine (2,2-dimethylbicyclo[2.2.1]hept-3-ylmethyl)phosphine (camPH₂). The compound has been characterised by NMR spectroscopy, and as its tris(hydroxymethyl)phosphonium chloride salt [camP(CH₂OH)₃]Cl, synthesised by reaction with excess formaldehyde and hydrochloric acid. The X-ray crystal structure of this phosphonium salt is reported, confirming the endo position of the phosphonium group. On treatment with triethylamine base, camP(CH₂OH)₃ ⁺Cl⁻ is converted to the hydroxymethylphosphine camP(CH₂OH)₂. The sulfide and selenide of this phosphine have been prepared, together with the platinum(II) complex cis-[PtCl₂{camP(CH₂OH)₂}₂]. The gas-phase decomposition of camPH₂ has been investigated using the technique of IR laser powered homogeneous pyrolysis. Results indicate the initial elimination of phosphine, followed by the rearrangement and decomposition of camphene through two distinct pathways

Camphene-derived primary and hydroxymethyl phosphines

Thermal disproportionation of (2,2-dimethylbicyclo[2.2.1]hept-3-ylmethyl)phosphinic acid (endo-8-camphanylphosphinic acid, camPO₂H₂) yields the primary phosphine (2,2-dimethylbicyclo[2.2.1]hept-3-ylmethyl)phosphine (camPH₂). The compound has been characterised by NMR spectroscopy, and as its tris(hydroxymethyl)phosphonium chloride salt [camP(CH₂OH)₃]Cl, synthesised by reaction with excess formaldehyde and hydrochloric acid. The X-ray crystal structure of this phosphonium salt is reported, confirming the endo position of the phosphonium group. On treatment with triethylamine base, camP(CH₂OH)₃ ⁺Cl⁻ is converted to the hydroxymethylphosphine camP(CH₂OH)₂. The sulfide and selenide of this phosphine have been prepared, together with the platinum(II) complex cis-[PtCl₂{camP(CH₂OH)₂}₂]. The gas-phase decomposition of camPH₂ has been investigated using the technique of IR laser powered homogeneous pyrolysis. Results indicate the initial elimination of phosphine, followed by the rearrangement and decomposition of camphene through two distinct pathways