Asmis Knut R, Beele Björn B, Jenne Carsten, Kawa Sebastian, Knorke Harald, Nierstenhöfer Marc C, Wang Xue-Bin, Warneke Jonas, Warneke Ziyan, Yuan Qinqin
Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstr. 2, 04103, Leipzig, Germany.
Fakultät für Mathematik und Naturwissenschaften, Anorganische Chemie, Bergische Universität Wuppertal, Gaußstr. 20, 42119, Wuppertal, Germany.
Chemistry. 2020 Nov 17;26(64):14594-14601. doi: 10.1002/chem.202003537. Epub 2020 Oct 5.
Nitro-functionalized undecahalogenated closo-dodecaborates [B X (NO )] were synthesized in high purities and characterized by NMR, IR, and Raman spectroscopy, single crystal X-diffraction, mass spectrometry, and gas-phase ion vibrational spectroscopy. The NO substituent leads to an enhanced electronic and electrochemical stability compared to the parent perhalogenated [B X ] (X=F-I) dianions evidenced by photoelectron spectroscopy, cyclic voltammetry, and quantum-chemical calculations. The stabilizing effect decreases from X=F to X=I. Thermogravimetric measurements of the salts indicate the loss of the nitric oxide radical (NO ). The homolytic NO elimination from the dianion under very soft collisional excitation in gas-phase ion experiments results in the formation of the radical [B X O] . Theoretical investigations suggest that the loss of NO proceeds via the rearrangement product [B X (ONO)] . The O-bonded nitrosooxy structure is thermodynamically more stable than the N-bonded nitro structure and its formation by radical recombination of [B X O] and NO is demonstrated.
硝基官能化的十一卤代闭式十二硼酸盐[B₁₂X₁₁(NO₂)]以高纯度合成，并通过核磁共振、红外和拉曼光谱、单晶X射线衍射、质谱和气相离子振动光谱进行表征。与母体全卤代[B₁₂X₁₂]²⁻（X = F - I）二价阴离子相比，NO₂取代基导致电子和电化学稳定性增强，光电子能谱、循环伏安法和量子化学计算证明了这一点。稳定作用从X = F到X = I逐渐减弱。盐的热重测量表明一氧化氮自由基（NO₂）的损失。在气相离子实验中，在非常温和的碰撞激发下，二价阴离子发生均裂NO消除，生成自由基[B₁₂X₁₁O]⁻。理论研究表明，NO的损失通过重排产物[B₁₂X₁₁(ONO)]⁻进行。O键合的亚硝基氧基结构在热力学上比N键合的硝基结构更稳定，并且证明了它是由[B₁₂X₁₁O]⁻和NO通过自由基重组形成的。
