Takeshita Tyler Y, Dunning Thom H
Department of Chemistry, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States.
J Phys Chem A. 2016 Sep 1;120(34):6846-50. doi: 10.1021/acs.jpca.6b06283. Epub 2016 Aug 19.
Crabtree et al. recently reported the microwave spectrum of nitrosyl-O-hydroxide (trans-NOOH), an isomer of nitrous acid, and found that this molecule has the longest O-O bond ever observed: 1.9149 Å ± 0.0005 Å. This is in marked contrast to the structure of the valence isoelectronic trans-NSOH molecule, which has a normal NS-OH bond length and strength. Generalized valence bond calculations show that the long bond in trans-NOOH is the result of a weak through-pair interaction that singlet couples the spins of the electrons in singly occupied orbitals on the hydroxyl radical and nitrogen atom, an interaction that is enhanced by the intervening lone pair of the oxygen atom in NO. The NS-OH bond is the result of the formation of a stable recoupled pair bond dyad, which accounts for both its length and strength.
克拉布特里等人最近报道了亚硝酸的一种异构体——亚硝酰基 - 氢氧化物（反式 - NOOH）的微波光谱，并发现该分子具有迄今观测到的最长的O - O键：1.9149 Å ± 0.0005 Å。这与价电子等电子体反式 - NSOH分子的结构形成显著对比，后者具有正常的NS - OH键长和键强。广义价键计算表明，反式 - NOOH中的长键是一种弱的通过对相互作用的结果，这种相互作用使单重态耦合了羟基自由基和氮原子上单占据轨道中电子的自旋，而NO中氧原子的居间孤对电子增强了这种相互作用。NS - OH键是形成稳定的重新耦合对键二元组的结果，这解释了其键长和键强。
