Theoretical model study of adsorbed antimalarial-graphene dimers: doping effects, photophysical parameters, intermolecular interactions, edge adsorption, and SERS

Future diagnostics and therapy applications are in part riding on the discovery and implementation of new optical techniques and strategies (which often derive from dyads) for example, prediction of features in surface-enhanced Raman spectroscopy requires the study of chromophore-chromophore interactions involve intermolecular forces, drug delivery, and photo mechanisms which are of great interest. New matches between chromophore systems (i.e. FRET), and π-delocalized surfaces are important to study. We explore low-molecular weight drug molecules and their interaction with the reporter material/surface of graphene. Bonding, charge transfer and orbital interactions for 2-amino-5-(1-methyl-5-nitro-2-imidazolyl)-1,3,4-thiadiazole (megazol or AMIT) on graphene were carried out. The graphene model substrate was monotonically/monatomically substituted (doped) with one neutral heteroatom (N/O/S/B) in place of one carbon center; chemical adsorption of AMIT is due to charge transfer from doped graphene to AMIT (DFT). Our AMIT-nanocluster studies show that the nanoclusters will act as a sensor component for the detection of drugs due to SERS. Our findings identified that the greater the energy of the charge transfer, the stronger the calculated chemical adsorption. Additionally, charge transfer is highest for the N-doped systems and least for pristine graphene, resulting in a stronger adsorption energy for N-doped graphene. Mulliken charge analysis of structures confirms enhancement found in QD-AMIT systems. Communicated by Ramaswamy H. Sarma未来的诊断与治疗应用，在一定程度上有赖于新型光学技术与策略（此类技术通常源自二元体系）的发现与应用。例如，表面增强拉曼光谱（surface-enhanced Raman spectroscopy, SERS）的特征预测，需要研究生色团-生色团相互作用，这类相互作用涉及分子间作用力、药物递送以及光作用机制，均具有重要研究价值。 生色团体系（即福斯特共振能量转移，FRET）与π离域表面之间的新型匹配关系，同样具有重要研究意义。 本研究探究了低分子量药物分子及其与石墨烯报告材料/表面的相互作用。针对石墨烯表面的2-氨基-5-(1-甲基-5-硝基-2-咪唑基)-1,3,4-噻二唑（megazol，简称AMIT），我们开展了成键、电荷转移及轨道相互作用相关研究。石墨烯模型基底通过单原子取代（掺杂）方式，以一个中性杂原子（N/O/S/B）替换其中一个碳原子中心；AMIT的化学吸附源于掺杂石墨烯向AMIT发生的电荷转移（密度泛函理论，DFT）。 我们针对AMIT-纳米团簇的研究表明，借助表面增强拉曼散射效应（SERS），该纳米团簇可作为药物检测的传感元件。研究结果显示，电荷转移能量越高，计算得到的化学吸附作用越强。此外，氮掺杂体系的电荷转移量最高，原始石墨烯的电荷转移量最低，因此氮掺杂石墨烯的吸附能更强。 对结构的马利肯电荷分析证实了量子点（QD）-AMIT体系中的增强效应。本文由Ramaswamy H. Sarma通讯。