Solid state, structural and solution studies on bis(2-methylbenzyl)-selenide, methyl(2,4,6-tri-t-butylphenyl)-selenide, bis(2,4,6-tri-methylphenyl)-diselenide, and bis(2,4,6-tri-t-butylphenyl)-diselenide

摘要

Two selenides, (2-MeBz)_2Se (1) and MeMes~*Se (2) and two diselenides, Mes_2Se_2 (3) and Mes_2~* Se_2 (4) have been prepared and characterized by single-crystal X-ray diffraction and by NMR spectroscopy. The structure of 1 was solved in the orthorhombic space group Pbca (no. 61) with cell constants a = b = 13.944 (10) A, c = 14.30 (2) A. The structure of 2 was determined in space group P1 (no. 2) with cell constants a = 5,9443 (5) A, b = 18.665 (2) A, c = 26.372 (3) A, #alpha# = 99.392(2)deg, #beta#=90.890 (2) deg and #gamma#=92.703 (2) deg. The structures of 3 and 4 were determined in the monoclinic space group P2_1/c (no. 14) with unit cell parameters for 3 of a = 6.333 (1) A, b = 18.370 (4) A, c = 5.122(3) A, #beta# = 97.42(3) deg and for 4, a = 11.359 (5) A, b = 10.520 (8) A, c = 30.22 (2) A and #beta# = 98.94(4)deg . A rotational process has been studied in 4 and the kinetics and thermodynamic parameters for this process are determined from DNMR measurements using three different methods, measurement of coalescence temperatures, calculation of kinetic parameters using the line half-width approximation, and by full line shape analysis. The results from these three methods were compared.