Costa José C S, Lima Marco A L, Mendes Adélio, Santos Luís M N B F
CIQUP, Centro de Investigação em Química da Universidade do Porto, Department of Chemistry and Biochemistry, Faculty of Science, University of Porto Portugal
LEPABE, Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto Portugal.
RSC Adv. 2020 Mar 24;10(20):11766-11776. doi: 10.1039/d0ra01518k. eCollection 2020 Mar 19.
The impact of structural differentiation between phenylcarbazoles (PhC, mCP, CBP, TCB) and phenylamines (TPA, BDB, TPB, TDAB) on the phase equilibria, optical spectrum, band gap, and thin-film morphology is evaluated and discussed. The carbazolyl units lead to a lower electronic conjugation contributing to a wide band gap when compared with the diphenylamine analogs. The fusion and sublimation equilibria indicate that entropic contribution is the key factor for the distinguished melting behavior and solid-phase volatility between phenylcarbazole derivatives and phenylamine analogs. The molecular differentiation between the two classes of compounds is not reflected in the crystal packing and intermolecular interactions. However, compared with the diphenylamino groups, the incorporation of carbazolyl moieties contributes to a less flexible molecule. Moreover, the results evidence that intermolecular bonding disruption along the fusion transition is more extensive for phenylamine derivatives. Due to the asymmetric nonplanar structure, mCP is characterized by a ratio of { / ≈ 3/4} while the more symmetric CBP and TCB molecules display ratios closer to { / ≈ 2/3}. Vapor-deposited thin films of mCP, CBP, and TCB are amorphous and their morphology is highly dependent on the substrate roughness. The lower flexibility of nonplanar phenylcarbazoles induces the formation of a glassy state due to the harder packing mechanism leading to the lower ability of the crystallization process.
评估并讨论了苯基咔唑（PhC、mCP、CBP、TCB）和苯胺（TPA、BDB、TPB、TDAB）之间的结构差异对相平衡、光谱、带隙和薄膜形态的影响。与二苯胺类似物相比，咔唑基单元导致较低的电子共轭，从而产生较宽的带隙。熔融和升华平衡表明，熵的贡献是苯基咔唑衍生物和苯胺类似物之间显著的熔化行为和固相挥发性的关键因素。这两类化合物之间的分子差异并未体现在晶体堆积和分子间相互作用中。然而，与二苯胺基相比，咔唑基部分的引入使分子的柔韧性降低。此外，结果表明，对于苯胺衍生物，沿熔融转变的分子间键破坏更为广泛。由于不对称的非平面结构，mCP的{ / ≈ 3/4}，而对称性更高的CBP和TCB分子的该比例更接近{ / ≈ 2/3}。mCP、CBP和TCB的气相沉积薄膜是非晶态的，其形态高度依赖于衬底粗糙度。非平面苯基咔唑较低的柔韧性由于更紧密的堆积机制导致结晶过程能力较低，从而诱导形成玻璃态。
