The ability to modulate the rate of Z/E isomerization of azobenzene (AB) derivatives is crucial to the practical applications of biological and photofunctional systems. Four kinds of AB–OC₄H₈–R derivatives (AB-1, R = NMe₃⁺I^–; AB-2, R = NH₂; AB-3, R = C₆H₁₃; AB-4, R = SH) were incorporated into liquid-exfoliated black phosphorus (BP) nanosheets through noncovalent functionalization. Experiments indicated that the switching process between the two states, trans (E) and cis (Z), especially the Z-to-E thermal conversion of AB derivatives, was accelerated 2–23 times by the presence of phosphorene at temperatures of 293–313 K. The acceleration phenomenon was rationalized by density functional theory (DFT) calculations, which reveals that the interaction between phosphorene and AB derivatives stabilized the Z isomer and transition state of azobenzene in a less degree than the E isomer, hence lowering the activation energy (E_a) of the Z-to-E isomerization. A close correlation is shown between the extent of charge transfer, the binding energy, and the Z-to-E thermal activation energy. The reactive molecular dynamics simulations also demonstrated a threefold faster isomerization process for AB@BP hybrids to accomplish the thermal relaxation relative to the free-standing AB. The predicted energy difference between E and Z isomers of AB@BP hybrids are enhanced 2–3 times upon deposition on the BP substrate. The photoresponsive AB@BP system suggests a new platform for energy conversion and potential applications in the biological field.

中文翻译：

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与磷的非共价相互作用促进偶氮苯衍生物的Z-to-E热异构化：理论预测和实验研究

调节偶氮苯（AB）衍生物的Z / E异构化速率的能力对于生物和光功能系统的实际应用至关重要。四种AB–OC ₄ H ₈ –R衍生物（AB-1，R = NMe ₃ ⁺ I ^–； AB-2，R = NH ₂； AB-3，R = C ₆ H ₁₃； AB-4，R通过非共价官能团将其掺入液体剥落的黑磷（BP）纳米片中。实验表明，反态（E）和顺态在两种状态之间的切换过程（Z），特别是AB衍生物从Z到E的热转化，在293-313 K的温度下由于存在磷而加速了2-23倍。加速现象通过密度泛函理论（DFT）计算得到合理化，这表明磷烯与AB衍生物之间的相互作用使Z异构体和偶氮苯的过渡态比E异构体稳定的程度小，从而降低了活化能（E _aZ-to-E异构化）。电荷转移的程度，结合能和Z-to-E热活化能之间显示出密切的相关性。反应性分子动力学模拟还证明了AB @ BP杂化物的异构化过程快了三倍，相对于独立式AB而言，它可以实现热弛豫。在BP底物上沉积后，AB @ BP杂化物的E和Z异构体之间的预测能量差增加了2-3倍。光响应AB @ BP系统为生物领域的能量转换和潜在应用提供了一个新平台。