Muñoz Salomé, Alvarado-Soto Leonor, Gaete José, Morales-Verdejo Cesar, Ramírez-Tagle Rodrigo
Centro Integrativo de Biología y Química Aplicada (CIBQA), Universidad Bernardo OHiggins, General Gana 1702, Santiago, Chile.
Dirección de Investigación y Postgrado, Universidad de Aconcagua, Pedro de Villagra 2265, Vitacura.
ACS Omega. 2022 Jun 1;7(23):19152-19157. doi: 10.1021/acsomega.1c07202. eCollection 2022 Jun 14.
This contribution describes a novel method for the detection of trace amounts of trinitrotoluene (TNT) using a cluster of hexamolybdenum with general formula [MoCl]. The molybdenum cluster was characterized by UV-visible, FT-IR, and fluorescence techniques, and the synthesis was efficient and reproducible. The evaluation of the molybdenum cluster by TNT detection was perfomed by fluoresecent measurements, and the results were interpreted by the Stern-Volmer equation, obtaining values of 2.9 × 10 and 1.6 × 10 M in different concentration ranges. Further, the results suggest that at TNT concentrations higher than 4 × 10 mM (0.01 mg L) it is possible to measure the quenching of the cluster fluorescence. The DFT calculations indicate that the contribution of the TNT in the active lowest unoccupied molecular orbitals that are involved in the higher intensity transitions in the complex cluster-TNT are significant. This situation differs from all the luminescent [MXL] clusters (M = Mo; X = facial bridging ligand, and L = labile axial ligands), where most of the closely spaced excited states are located in the {MX} core. Thus, the TNT switches off the cluster luminescence. The approach using a [MoCl]-based fluorescence sensor has the potential to be a sensing technology for the detection of nitroaromatic explosives.
本论文描述了一种使用通式为[MoCl]的六钼簇检测痕量三硝基甲苯（TNT）的新方法。通过紫外可见光谱、傅里叶变换红外光谱和荧光技术对钼簇进行了表征，其合成方法高效且可重复。通过荧光测量对钼簇进行TNT检测评估，并根据斯特恩-沃尔默方程解释结果，在不同浓度范围内得到的值分别为2.9×10和1.6×10 M。此外，结果表明，当TNT浓度高于4×10 mM（0.01 mg L）时，可以测量簇荧光的猝灭。密度泛函理论计算表明，TNT在参与簇-TNT复合物中高强度跃迁的活性最低未占据分子轨道中的贡献显著。这种情况与所有发光的[MXL]簇（M = Mo；X = 面桥连配体，L = 不稳定轴向配体）不同，在这些簇中，大多数紧密间隔的激发态位于{MX}核中。因此，TNT会关闭簇的发光。使用基于[MoCl]的荧光传感器的方法有潜力成为一种检测硝基芳香族炸药的传感技术。
