【摘要】 文章考察了Mo—SiO₂催化剂体系在丙烯歧化反应过程中的动态ESR波谱,发现在催化歧化反应过程中有两种Mo⁵⁺顺磁中心,一种为扰动八面体配位,g（?）=1.89,g=1.94;另一种为扰动四棱锥配位,g=1。86,g=1.95。测得同位素95,97Mo⁵⁺的各向异性超精细耦合常数;观测到反应产生的积炭信号,g≈2.002;氧阴离子自由基信号g₁=2.018,g₂=2.011,g₃=2.005用LCAO—MO理论对上述Mo⁵⁺的ESR波谱进行计算,求得分子轨道系数,发现并总结出与△g成直线关系,并建议用之比值作为衡量C_4v扰动程度的尺度。更多还原

【Abstract】 ESR Spectra of molybdenum supported catalysts（Mo-Sio₂） were recorded with various contact time with propene.Two types of Mo⁵⁺_- paramegnetic centers were formed during the course of reaction. The one having g=1.89, g = 1.94 is due to the distorted octahadral coordination, while the other with g = 1.86, g = 1.95 is a square pyramidal distorted species.However,they are both approximately of Civ symmetry. The anisotropic surperfine coupling contants A =90.3 10（-4） cm（-1）,A = 44.8 10^-4 cm^-1 of ^95,97Mo⁵⁺_- were also detected. Meanwhile, the signals occurerd at ca. g = 2.002 and g1 = 2.018,g2 = 2.011,g3 = 2.005 were assigned to coking from propene and anionic radical 02- respectively. LCAO-MO approximate calculations of data led to a set of molecular orbital coefficients. It was found that theplot of vs. △g is linear. Suggestion was made to employas a better measure of the extent of C4v distortion for Mo5 +更多还原