Boche Gernot, Möbus Konrad, Harms Klaus, Lohrenz John C W, Marsch Michael
Fachbereich Chemie der Philipps-Universität Marburg D-35032 Marburg (Germany) Fax: Int. code +(6421)28-8917.
Chemistry. 1996 May;2(5):604-607. doi: 10.1002/chem.19960020521.
The X-ray crystal structure of the dodecameric lithium tert-butylperoxide [2] is the first of an alkali or alkaline earth peroxide. It shows the lithium ion bridging the two oxygen atoms of the peroxide unit and a slight lenghtening of the O-O bond, in agreement with quantum-chemical calculations. A calculation for the model reaction of MeLi with LiOOH to give MeOLi and LiOH reveals the importance of Li bridging the O-O bond in the transition state of this reaction, as similarly discussed for many oxidation reactions of (transition-) metal peroxides. Preliminary theoretical studies of the O-O bond length (and thus of the oxenoid character) as a function of the aggregation of 2 disclose that increasing aggregation leads to stabilization of the charge at the anionic oxygen atom and thus to a reduction of the O-O bond length (oxenoid character). Related considerations of the effect of aggregation should also be valid for other lithium (organometallic) compounds and their structure and reactivity as well as other properties.
十二聚体叔丁基过氧化锂[2]的X射线晶体结构是碱金属或碱土金属过氧化物中的首例。它显示锂离子桥连过氧化物单元的两个氧原子，且O-O键略有伸长，这与量子化学计算结果一致。对甲基锂与氢氧化锂反应生成甲氧基锂和氢氧化锂的模型反应进行的计算表明，在该反应的过渡态中，锂桥连O-O键很重要，这与许多（过渡）金属过氧化物的氧化反应情况类似。对O-O键长度（进而对氧烯特征）随2的聚集情况变化的初步理论研究表明，聚集程度增加会导致阴离子氧原子上的电荷稳定，从而使O-O键长度缩短（氧烯特征减弱）。关于聚集效应的相关考量对于其他锂（有机金属）化合物及其结构、反应性以及其他性质也应是有效的。
