H-ZSM-5沸石表面吸附态烯烃正离子自由基的不等价磁相互作用的ESR研究

本文报道在经氧气高温处理后的H-ZSM-5沸石所生成的多种开链及闭环的乙烯正离子基衍生物、利用计算机模拟了解在沸石孔洞内的化学吸附情形、同时帮助判定正确的超精细作用产生的非等价质子偶合常数,利用-乙烯正离子基的磁不对称性了解自由基与沸石产生的作用及离子-分子间的化学反应.本文提出一个新方程式,它利用分子的对称性来了解这些正离子自由基的非平面性的几何形状.

H-ZSM-5 CATALYTIC MATERIALS FOR CHEMICAL REACTIONS AND MAGNETIC NON-EQUIVALENCE STUDIED BY ELECTRON SPIN RESONANCE TECHNIQUES

We reported both the open-chain and closed-ring ethene cation radicals derivatives formation on pretreated H-ZSM-5 studied by ESR techniques and the use of colnputer simulations at various stages to understand the details of chemical reactions inside the three-dimensional channels of the zeolite. The comparison of these four related open chain cation radicals with two related closed ring cyclopentene and cyclohexene canon radicals shows that the unequivalent β-proton hyperfine splittings in the 2,3-dimethyl-2-hexene cation radicals can be understood by the contact of these canon molecules within the three-dimensional pore structure. Thus, we use the computer simulations to help us correct assignment of the isotropic proton hyperfine splittings on the surface as well as to study both the intramolecular hindered torsional motions of the solid-gas interactions and ion-molecule reactions.A new equation relating the observed proton hyperfine splitting to the non-planar structure of the cation radicals is proposed. The equation is supported by the basic symmetry principle as well as our experimental results.