In order to design biosensors, it is quite necessary to have an insight upon the nature of interaction between the modified nucleic bases (MNBs) and carbonaceous materials. This study is focussed upon the interaction of the various doped graphene models like graphene (GR), aluminium doped graphene (AlG), sulphur doped graphene (SG), nickel doped graphene (NiG), chromium doped graphene (CrG) and germanium doped graphene (GeG) with MNBs (caffeine, hypoxanthine, uric acid and xanthine) by employing the electronic structure calculations and the associated methodology. All the geometries considered in this study (MNBs and graphene models) were initially optimized at M06-2X/6-31+G** basis set without any constraints followed by the single point energy calculation at three different and well established methods using the Gaussian 09 software package. A detailed comparison of the interaction energy is accomplished in this study. The interaction energy values were further corrected for the basis set superposition error. The theory of atoms in molecules analysis is also performed in detail, which showcases the bond critical points, Laplacian and various other parameters of interest. The variation of frontier molecular orbitals, i.e., highest occupied molecular orbital–lowest unoccupied molecular orbital gap for different models of graphene have been discussed in detail upon the adsorption of MNBs. Among the doped graphene models, the graphene model doped with Cr seems to be more suitable for the application of sensors, also it is found that the MNBs interact primarily via $$\pi $$ π – $$\pi $$ π interaction. The results highlight that the CrG can act as a sensor for the detection of MNBs.

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修饰的核酸碱基与石墨烯和掺杂石墨烯的相互作用：DFT 研究

为了设计生物传感器，非常有必要了解修饰的核酸碱基 (MNB) 与含碳材料之间的相互作用的性质。本研究侧重于各种掺杂石墨烯模型的相互作用，如石墨烯 (GR)、铝掺杂石墨烯 (AlG)、硫掺杂石墨烯 (SG)、镍掺杂石墨烯 (NiG)、铬掺杂石墨烯 (CrG) 和锗掺杂石墨烯(GeG) 与 MNB（咖啡因、次黄嘌呤、尿酸和黄嘌呤）通过电子结构计算和相关方法。本研究中考虑的所有几何形状（MNB 和石墨烯模型）最初在 M06-2X/6-31+G** 基组上进行优化，没有任何限制，然后使用高斯分布在三种不同且完善的方法中进行单点能量计算09 软件包。在这项研究中完成了相互作用能的详细比较。针对基组叠加误差进一步校正相互作用能值。还详细介绍了分子分析中的原子理论，其中展示了键临界点、拉普拉斯算子和其他各种感兴趣的参数。前沿分子轨道的变化，即不同模型石墨烯的最高占据分子轨道 - 最低未占据分子轨道间隙已经在 MNB 吸附时进行了详细讨论。在掺杂的石墨烯模型中，掺杂Cr的石墨烯模型似乎更适合传感器的应用，并且发现MNB主要通过$$\pi $$ π-$$\pi $$π相互作用进行相互作用。结果突出表明，CrG 可以作为检测 MNB 的传感器。