Langer Peter, Amiri Shadi, Bodtke Anja, Saleh Nehad N R, Weisz Klaus, Görls Helmar, Schreiner Peter R
Institut für Chemie, Universität Rostock, Albert-Einstein-Str. 3a, D-18059 Rostock, Germany.
J Org Chem. 2008 Jul 4;73(13):5048-63. doi: 10.1021/jo8005123. Epub 2008 May 22.
Toward the goal of preparing stable, neutral open-shell systems, we synthesized a novel series of p-phenyl-substituted 3,5,7,9-hexaazaacridine and 3,5,7,9-hexaazaanthracene derivatives. The effects of substitution on the molecular electronic properties were probed both experimentally and computationally [B3LYP/6-311G(d,p)//B3LYP/6-31G(d,p)]. While the experimentally prepared structures already have small (20-25 kcal/mol) singlet-triplet energy gaps, systems with even smaller (<9 kcal/mol) singlet-triplet energy separations can be realized through systematic variation of the substituent numbers, types, and patterns. Hexaazaanthracenes show generally smaller singlet-triplet energy gaps than hexaazaacridines. Nitrogen-bonded sigma- and pi-acceptor substituents that cause positive inductive and mesomeric effects as well as carbon-bonded sigma-donor substituents make substituted hexaazaanthracenes promising candidates for purely organic high-spin systems.
为了实现制备稳定的中性开壳体系这一目标，我们合成了一系列新型的对苯基取代的3,5,7,9-六氮杂吖啶和3,5,7,9-六氮杂蒽衍生物。通过实验和计算[B3LYP/6-311G(d,p)//B3LYP/6-31G(d,p)]探究了取代基对分子电子性质的影响。虽然实验制备的结构已经具有较小（20-25千卡/摩尔）的单重态-三重态能隙，但通过系统改变取代基的数量、类型和模式，可以实现具有更小（<9千卡/摩尔）单重态-三重态能量间隔的体系。六氮杂蒽的单重态-三重态能隙通常比六氮杂吖啶小。导致正诱导效应和中介效应的氮键合σ和π受体取代基以及碳键合σ供体取代基使得取代的六氮杂蒽成为纯有机高自旋体系的有前途的候选物。
