Department of Chemistry, Middle Tennessee State University, Murfreesboro, TN, 37132, USA.
Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363, Łódź, Poland.
Chemistry. 2019 Feb 18;25(10):2616-2630. doi: 10.1002/chem.201805392. Epub 2019 Jan 21.
Two series of 1,12-bis-zwitterionic derivatives of the [closo-B H ] anion (B), containing either two 4-alkoxypyridinium groups (1B[n]-p) or one 4-alkoxypyridinium and one 4-pentylthianium groups (2B[n]-p), were prepared and their structural (XRD, DFT), thermal, and photophysical properties were compared with those of the analogous derivatives of the [closo-B H ] anion (1A[n]-p and 2A[n]-p). Some 1,7-derivatives of B were isolated and investigated. Both series 1[n] and 2[n] exhibit nematic and crystalline polymorphism; the 12-vertex derivatives (B) have higher transition temperatures than those of the 10-vertex analogues (A). All compounds fluoresce with quantum yields higher for 1B (Φ =0.37 for 1B[7]-p and Φ =0.27 for 2B[7]-p) than those for the 10-vertex analogues (Φ =0.04 for 2A[5]-p). DFT calculations demonstrate an order of magnitude lower first hyperpolarizability, β , for 2B[7]-p than that for the 10-vertex analogue 2A[7]-p (1.7×10 vs. 18.9×10 esu at ω=0).
两个系列的 1,12-双两性离子衍生物的[closo-B H ]阴离子（B），含有两个 4-烷氧基吡啶鎓基团（1B[n]-p）或一个 4-烷氧基吡啶鎓和一个 4-戊基噻鎓基团（2B[n]-p），被制备并比较了它们的结构（XRD，DFT），热和光物理性质与[closo-B H ]阴离子的类似衍生物（1A[n]-p 和 2A[n]-p）。分离并研究了一些 1,7-衍生物的 B。两个系列 1[n]和 2[n]都表现出向列相和结晶多态性；12 顶点衍生物（B）比 10 顶点类似物（A）具有更高的转变温度。所有化合物都具有荧光量子产率，1B 的荧光量子产率更高（1B[7]-p 的 Φ =0.37，2B[7]-p 的 Φ =0.27），而 10 顶点类似物的荧光量子产率更低（2A[5]-p 的 Φ =0.04）。DFT 计算表明，2B[7]-p 的第一个超极化率β比 10-顶点类似物 2A[7]-p 低一个数量级（ω=0 时，1.7×10 与 18.9×10 ，esu）。
