Molecular structures of vinylarsine, vinyldichloroarsine and arsine studied by gas-phase electron diffraction and quantum chemical calculations

The molecular structures of vinylarsine (CH2CHAsH2), vinyldichloroarsine (CH2CHAsCl2) and arsine (AsH3) have been determined from gas-phase electron diffraction data and, in the case of vinylarsine, rotation constants, employing the SARACEN method. The structure of vinylarsine represents the first complete gas-phase structure of a primary arsine. The experimental geometric parameters generally show good agreement with those obtained using ab initio calculations. Key structural parameters (rh1) for vinylarsine are rAs–H = 150.5(4) pm, rAs–C = 195.1(1) pm and ∠C–C–As = 119.4(2)°. The bonding and conformational trends in both vinylarsine and vinyldichloroarsine are compared to those found in the analogous amines and phosphines.