New synthetic procedures to catena-phosphorus cations: preparation and dissociation of the first cyclo-phosphino-halophosphonium salts.

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. The new cations represent phosphine complexes of the [PCy](2+) and [P(2)Cy(2)](2+) cationic fragments from [20](2+), demonstrating the coordinate nature of the phosphinophosphonium bonds in cyclo-phosphino-halophosphonium cations. The compounds have been characterized by NMR spectroscopy, single crystal X-ray crystallography, and Raman spectroscopy.

Understanding the electronic structure, reactivity, and hydrogen bonding for a 1,2-diphosphonium dication.

The experimental charge density for hexamethyldiphosphonium ditriflate has been determined from low-temperature high-resolution X-ray diffraction data. These results have been compared with theoretically calculated values for the isolated gas-phase compound. Analysis of the topological and atomic basin properties has provided insight into the exact nature of the P-P bond in both the crystalline and the gas-phase structures. The rho(b)(r) and nabla2rho(b)(r) values highlight the covalent nature of the P-P bond, while the atomic charges indicate a localization of the positive charges on the two phosphorus atoms. This seems to indicate that a covalent bond is formed despite a strong electrostatic repulsion between these two heteroatoms. The topological properties and electrostatic potentials have also been shown to provide significant insight into the chemical reactivity of the title compound. A topological analysis of P2Me4, P2Me5(+), and P2Me6(+2) species has provided information about the progression of the P-P bond in the synthesis of the title compound. An investigation of the different hydrogen-bonding networks present in the crystalline and gas-phase structures, along with their affect on the electronic structure of the title compound has also been investigated. This has all led to significant new insight into the electronic structure, reactivity, and weak hydrogen bonding in prototypical 1,2-diphosphonium dications.

Bifunctional diphosphorus Lewis acids from cyclodiphosphadiazanes.

The quantitative displacement of triflate groups in 1,3-ditriflato-2,4-bis(2,6-dimethylphenyl)cyclodiphospha-2,4-diazane by DMAP (4-dimethylaminopyridine) or Me(3)P gives dicationic complexes containing bifunctional diphosphorus Lewis acceptors.

A second polymorph of bis(dimethylphosphino)dimethylphosphonium trifluoromethanesulfonate.

The title compound, C(6)H(18)P(3)(+) x CF(3)SO(3)(-), crystallizes in two polymorphic forms in the space groups P2(1)/c and Pnma. In the orthorhombic form, the two crystallographically independent molecular units lie across a crystallographic mirror plane. The compound lacks traditional hydrogen-bond donors and, hence, is held together by weak C-H...O and C-H...F interactions, forming layers. The second polymorph was obtained as a by-product from the reaction of 1,3-bis(2,6-dimethylphenyl)-2,4-ditriflato-1,3,2,4-diazadiphosphetidine with tetramethyldiphosphine.

Substituent effects on indium-phosphorus bonding in (4-RC6H4S)3In.PR'3 adducts (R = H, Me, F; R' = Et, Cy, Ph): a spectroscopic, structural, and thermal decomposition study.

The tris(arylthiolate)indium(III) complexes (4-RC(6)H(4)S)(3)In [R = H (5), Me (6), F (7)] were prepared from the 2:3 reaction of elemental indium and the corresponding aryl disulfide in methanol. Reaction of 5-7 with 2 equiv of the appropriate triorganylphosphine in benzene or toluene resulted in isolation of the indium-phosphine adduct series (4-RC(6)H(4)S)(3)In.PR'(3) [R = H, R' = Et (5a), Cy (5b), Ph (5c); R = Me, R' = Et (6a), Cy (6b), Ph (6c); R = F, R' = Et (7a), Cy (7b), Ph (7c)]. These compounds were characterized via elemental analysis, FT-IR, FT-Raman, solution (1)H, (13)C{(1)H}, (31)P{(1)H}, and (19)F (7a-c) NMR spectroscopy, and X-ray crystallography (5c, 6a, 6c, and 7a). NMR spectra show retention of the In-P bond in benzene-d(6) solution, with phosphine (31)P{(1)H} signals shifted downfield compared to the uncoordinated ligand. The X-ray structures show monomeric 1:1 adduct complexes in all cases. The In-P bond distance [2.5863(5)-2.6493(12) A] is influenced significantly by the phosphine substituents but is unaffected by the substituted phenylthiolate ligand. Relatively low melting points (88-130 degrees C) are observed for all adducts, while high-temperature thermal decomposition is observed for the indium thiolate reactants 5-7. DSC/TGA and EI-MS data show a two-step thermal decomposition process, involving an initial loss of the phosphine moiety followed by loss of thiolate ligand.