New Light on Late Transition Metal Complexes

本项目隶属于无机、生物无机和有机金属化学专业，旨在阐明铂（II）和铜（II）四配位配合物的方形平面激发态弛豫机制。这项工作是基于早期的观察，即这些化合物的激发态的寿命强烈地受到配合物与其环境的二次相互作用的影响。因此，它们具有作为分子探针和传感器的潜力。具体的研究将包括铂（II）三联吡啶和铜（II）卟啉配合物在流体介质和嵌入DNA中的光化学表征，并尝试通过取代对三联吡啶配体进行修饰来增加前者配合物的激发态寿命。将采用的技术包括发光、吸收和CD光谱，以及猝灭反应和温度相关测量。电磁辐射的吸收产生激发态，这些激发态可以通过非辐射（产生热量）或辐射（发射光）途径恢复（松弛）到基态。通过对辐照弛豫化合物发射光谱的研究，可以获得有关其电子结构的大量信息。辐射弛豫可以高度依赖于分子所处的环境，在有利的情况下，对发射光谱的观察可以用作分子环境的探针。这个项目的主要目标是更好地理解某些过渡金属化合物的激发态弛豫发生的方式，以及这些是如何由分子环境决定的。在许多领域有许多潜在的应用，包括光传感器、光动力癌症治疗和分子电子学。

This project, in the Inorganic, Bioinorganic, and Organometallic Chemistry Program, is concerned with elucidation of the mechanisms of excited state relaxation in square planar, four- coordinate complexes of platinum(II) and copper(II). The work is based upon earlier observations that the lifetimes of excited states of such compounds are strongly affected by secondary interactions of the complexes with their environments. As a result they have potential as molecular probes and sensors. Specific studies will include characterization of the photochemistry of platinum(II) terpyridine and copper(II) porphyrin complexes both in fluid media and intercalated into DNA, and attempts to increase the excited state lifetimes of the former complexes by modification of the terpyridine ligand through substitution. Techniques to be employed will include luminescence, absorption and CD spectroscopies in conjunction with quenching reactions and temperature dependent measurements. Absorption of electromagnetic radiation generates excited electronic states that may revert (relax) to the ground state by non-irradiative (heat generating) or irradiative (emission of light) pathways. A great deal of information can be obtained about the electronic structure of compounds that undergo irradiative relaxation by studies of their emission spectra. Irradiative relaxation can be highly dependent upon the environment in which the molecule resides and under favorable circumstances the observation of an emission spectrum can be used as a probe of the molecular environment. This project has as its major objective the development of a better understanding of the ways in which relaxation of excited states of certain transition metal compounds occur and how these are determined by the molecular environment. There are many potential applications in a number of areas including photosensors, photodynamic cancer therapy, and molecular electronics.