Grenon Nicole, Baumgartner Thomas
Department of Chemistry and Centre for Advanced Solar Materials, University of Calgary , 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada.
Inorg Chem. 2018 Feb 5;57(3):1630-1644. doi: 10.1021/acs.inorgchem.7b03008. Epub 2018 Jan 22.
The synthesis of a series of conjugated organophosphorus materials with intramolecular Lewis acid/base interactions and the exploration of the electronic nature of the bonding around the resulting hypervalent phosphorus centers are reported. To further establish the influence of increasing the size of the π-conjugated backbone, two scaffolds, thiazolyl-thiophene and benzothiazolyl-thiophene, were included in this study. Single-crystal X-ray crystallography of several of the compounds supports the hypervalent nature of the phosphorus center in the new species. Surprisingly, altering the Lewis acidity of the phosphorus center via oxidation or methylation impacts the coordinating mode of the thiazolyl substituent, which also has considerable impact on the photophysical and electrochemical properties of the π-conjugated molecular scaffolds. Through theoretical calculations involving natural bond orbital (NBO) analysis and atom-in-molecules (AIM) correlation, the existence and electronic nature of weak hypervalent bonding interactions around the phosphorus center was solidified as weak 3c-4e and/or σ-hole bonds, depending on the coordination mode of the peripheral thiazolyl substituent as well as the Lewis acidity of the phosphorus center.
本文报道了一系列具有分子内路易斯酸/碱相互作用的共轭有机磷材料的合成，以及对所得高价磷中心周围键合电子性质的探索。为了进一步确定增加π共轭主链尺寸的影响，本研究纳入了两种骨架结构，即噻唑基-噻吩和苯并噻唑基-噻吩。几种化合物的单晶X射线晶体学研究证实了新物种中磷中心的高价性质。令人惊讶的是，通过氧化或甲基化改变磷中心的路易斯酸度会影响噻唑基取代基的配位模式，这对π共轭分子骨架的光物理和电化学性质也有相当大的影响。通过涉及自然键轨道（NBO）分析和分子中的原子（AIM）相关性的理论计算，根据外围噻唑基取代基的配位模式以及磷中心的路易斯酸度，磷中心周围弱高价键相互作用的存在及其电子性质被确定为弱3c-4e和/或σ-空穴键。
