The crystal structures of 10,10'-bis(phenoxarsine) oxide and selenide

Abstract The reaction between 10,10′-bis(phenoxarsine) oxide (I) and HI gives 10-iodophenoxarsine. The latter, on treatment with H2Se give 10,10′-bis(phenoxarsine) selenide (II). The crystal structures of I and II have been determined from single crystal X-ray data. The unit cell for I is monoclinic, P21/c (No. 14) with a = 15.976(3) A, b = 10.582(2) A, c = 12.581(2) A, β = 111.70(1)° V = 2018.6 A3; d(calc.) = 1.65Mg/m3 at 23°C for four molecules per unit cell. From 3279 reflections for which I>0.5σ(I), F>σ(F), R = 0.041 with anisotropic thermal parameters for all non-hydrogen atoms and with fixed positions and thermal parameters for hydrogens. One of the phenoxarsina rings deviates from planarity by approximately 5° while the other deviates by more than 24°. The (As[sbnd]O) distances are 1.810(3) and 1.821(3) A for the flat and bent ring and the (As[sbnd]O[sbnd]As) angle is 122.3(1)°. The bond distances to As and O from C are nearly the same for both rings, but the bond angles with As and the ring O as t...