Department of Chemistry and Applied Biosciences, ETH Zürich, 8093 Zürich, Switzerland.
Department of Chemistry & Biochemistry, 1306 E. University Blvd., Tucson, AZ 85719, USA.
Molecules. 2020 Oct 15;25(20):4742. doi: 10.3390/molecules25204742.
The synthesis, isolation and full characterization of ion pairs between alkaline metal ions (Li, Na, K) and mono-anions and dianions obtained from -dibenzo[,]cycloheptenyl (CH = trop) is reported. According to Nuclear Magnetic Resonance (NMR) spectroscopy, single crystal X-ray analysis and Density Functional Theory (DFT) calculations, the trop and trop anions show anti-aromatic properties which are dependent on the counter cation M and solvent molecules serving as co-ligands. For comparison, the disodium and dipotassium salt of the dianion of dibenzo[]cyclooctatetraene (CH = dbcot) were prepared, which show classical aromatic character. A d-Rh(I) complex of trop was prepared and the structure shows a distortion of the CH ligand into a conjugated 10π -benzo pentadienide unit-to which the Rh(I) center is coordinated-and an aromatic 6π electron benzo group which is non-coordinated. Electron transfer reactions between neutral and anionic trop and dbcot species show that the anti-aromatic compounds obtained from trop are significantly stronger reductants.
报道了从 -二苯并[,]环庚烯（CH = trop）中获得的碱金属离子（Li、Na、K）与一价和二价阴离子形成的离子对的合成、分离和全谱学表征。根据核磁共振（NMR）光谱、单晶 X 射线分析和密度泛函理论（DFT）计算，trop 和 trop 阴离子显示反芳香性质，这取决于抗衡阳离子 M 和作为共配体的溶剂分子。作为比较，制备了二阴离子的二钠盐和二钾盐，它们显示出典型的芳香性。制备了 trop 的 d-Rh(I)配合物，结构显示 CH 配体扭曲成共轭的 10π-苯并戊二烯化物单元，Rh(I)中心与之配位，以及非配位的芳香 6π 电子苯基团。中性和阴离子 trop 和 dbcot 物种之间的电子转移反应表明，从 trop 获得的反芳香化合物是明显更强的还原剂。
