摘要
运用休克尔分子轨道 (HMO)理论对紫红质中的色基 -视黄醛骨架异构化现象进行了讨论。近似计算结果表明 :紫红质中视黄醛骨架共轭体系π→π* 跃迁的最大吸收峰λmax=5 63 nm,这与紫红质的 λmax=498nm相近 ,但更接近受压紫红质的实验结果 λmax=5 3 4nm;且视黄醛骨架结构共轭体系中 C11-C12 之间激发态的 π键级为 1 .5 860 ,明显小于基态 π键级 1 .7469值 ,故当紫红质吸收光能进入激发态之后 ,1 1
When rhodopsin absorbs a photon of light,11 cis retinal portion of rhodopsin is ultimately isomerized to the all trans form of metarhodopsin Ⅱ. Why? the phenomena is quantitatively interpreted to use Hückel molecular orbital(HMO) method. The calculation results show that the conjugated double bonds of 11 cis retinal portion of rhodopsin has an absorption maximum at 563 nm,which is the difference between π(HOMO) and π *(LUMO),and it is close to the experimental results(498 nm for rhodopsin and 534 nm for prelumirhodopsin).The π bond order between C 11 and C 12 is 1.586 0 in excited state less than 1.746 9 in ground state, so excited state 11 cis retinal portion of rhodopsin is easily isomerized to the all trans form of metarhodopsin Ⅱ when rhodopsin absorbs a photon of light.
出处
《宝鸡文理学院学报（自然科学版）》
CAS
2000年第2期126-129,共4页
Journal of Baoji University of Arts and Sciences(Natural Science Edition)
