Molecular Structure of Phenylphosphine and Its Analogs by Gas-Phase Electron Diffraction and Quantum-Chemical Calculations

The molecular structures of phenylphosphine and its analogs, aniline and phenylarsine, were studied by gas-phase electron diffraction and quantum-chemical methods. The geometry and force constants were calculated at the HF/6-31G and B3LYP/6-31G^* levels of theory. Phenylphosphine and phenylarsine possess a bisector conformation with asymmetric phenyl rings. The main geometric parameters are as follows (r _a): P-C 1.833(6), C-Cav 1.397(1)Å. The structures of molecules like X₂YPh (X = H, F, Cl; Y = N, P, As) were discussed.     

Molecular Structure of Tetrahydroxycalix[4]arene [-(C<Subscript>6</Subscript>H<Subscript>3</Subscript>OH)-CH<Subscript>2</Subscript>-]<Subscript>4</Subscript> in the Gas Phase

Gas-phase electron diffraction and HF/6-31G*, HF/6-31G**, and B3LYP/6-31G* ab initio calculations were used to find that in the gas phase at 242°C the calix[4]arene [-(C₆H₃OH)-CH₂-]₄ molecule possesses a C₄ conformation. Geometric parameters of the molecule were determined, and the energies of C-H?O hydrogen bonds (7.3 kcal mol^?1) were estimated by the AM1 method.     

Molecular Structure of Diphenylamine by Gas-Phase Electron Diffraction and Quantum Chemistry

Geometric parameters of the diphenylamine molecule were determined by gas-phase electron diffraction and quantum-chemical calculations. By gas-phase electron diffraction, the molecule has an asymmetric structure with torsion angles about N-C bonds of ?45.6(23)° and 173.4(46)°, which agrees with RHF/6-31G** calculations. Density functional theory (DFT) calculations at the B3LYP/6-31G** level of theory lead to a C ₂ molecular conformation in the ground electronic state. The principal experimental geometric parameters are as follows: bond lengths: C-N 1.417(1), C-C_av 1.403(1) Å; and bond angles: CNC 123.9(5)°, and NCC 121.5° (assumed) and 116.4°.     

Molecular Structure of 1,3,2-Diheterophospholenes in the Gas Phase. Effect of the Nature of Atoms in the Nearest Environment of the Phosphorous Atom on the P-X (X = F,Cl) Bond Length

Molecular parameters of 2-chloro-5-methyl-1,3,2-oxazaphospholene were repeatedly determined invoking nomempirical quantum-chemical calculations. The molecule has a P-envelope conformation with an axial P-Cl bond. Analysis of the molecular structures of 1,3,2-diheterophospholenes, studied experimentally and predicted by quantum-chemical calculations at different levels of theory is performed.     

Molecular Structure of Triphenylphosphine by Gas-Phase Electron Diffraction and ab initio Calculations

The molecular structure of triphenylphosphine was determined by gas-phase electron diffraction and quantum-chemical calculations. The symmetry of the molecule is C ₃ with the L_pPCC torsion angle of 32.2(3.0)°. The main geometrical parameters are as follows: bond distances, Å: P-Cl 1.839(2), C-Cav 1.400(1), and C-H 1.098(3); bond angles, deg: CPC 102.2(3), PCC 115.3(5), and CC _ipso C 119.4(4).     

Molecular Structure of Diphenylphosphine As Determined by Gas-Phase Electron Diffraction and Quantum-Chemical Calculations

Gas-phase electron diffraction was used to show the title molecule has an asymmetric structure with torsion angles around P-C bonds of 65° and 154(7)°. The principal geometric parameters are as follows: interatomic distances, Å: P-C 1.829 and 1.833(4), C-Cav 1.401(1); bond angles, deg: CPC 101.0(20), PCC 120.4 and 119.4(16). Quantum-chemical calculations of chlorodiphenylphosphine were performed.