MICROWAVE-SPECTRUM OF PREPARATION OF TETRAHYDRO-SELENOPHENE-ALPHA-D4 - STRUCTURE OF RING OF MOLECULE AND ALPHA-METHYLENE GROUPS

A study has been made of the microwave spectra of molecules of tetrahydroselenophene: alphaD4 - (C4H4Se)-C-12-Se-80 (I), alphaD3 - (C4H5Sc)-C-12-Sc-80 (II), alphaD4 - alphaC-13-(C3H4Se)-C-12-Se-80 (III), alphaD4 - betaC-13-(C3H4Se)-C-12-Se-80 (IV), alphD4 - (C4H4Se)-C-12-Se-72 (V). The rotational constants and centrifugal distortion constants of I have been determined, as well as the rotational constants of II-V, and the r(s)-structure of the nonplanar ring of the molecule (C2 symmetry without accounting for inversion) and of the a-methylene groups of I: C-Se = 1.963, C2-C3 = 1.535, C3-C4 = 1.524, C-D = 1.094 angstrom; also the angles CSeC = 90.3, SeCC = 105.5, CCC = 107.6, DCD = 109.3 and dihedral angle of ring twist phi = 28.2-degrees. It has been found that the local C2V symmetry in the structure of the a-methylene groups is disrupted.