DFT Calculation On The Complexes Containing Ru-Ru Bonds With ESBO And FSBO Symmetry

The study of the electronic structure characteristics of metal-metal bonds of transition complexes has always been a challenging subject in the field of quantum chemistry,because not only it has a relatively large molecular size,but also the electronic effects related to metal-metal bonding are very strong,leading to traditional ab initio methods are difficult to calculate these properties accurately.Recent developments in density functional theory calculations?DFT?show that the traditional quantum chemical calculation method DFT has become the most powerful tool in the field of computing.Our laboratory is dedicated to explore the application of the DFT method in the study of the electronic structural characteristics of metal-metal bonding systems.The interaction between the metal atoms in the dioctahedral symmetrical structure of the edge-sharing?ESBO?and face-sharing?FSBO?compounds in the field of metal multiple bonds is a research direction that has continuously attracted much attention.In this article,we use the experimentally obtained crystal structures of ESBO and FSBO complexes,to construct a calculation model,and use DFT theory to geometrically optimize the calculation model.We successfully obtained information about molecular orbitals.On the basis of geometric optimization,a natural bond orbit?NBO?analysis was performed to obtain its metal-metal bond.Combining the electron transition spectra obtained from the experiment,we also performed time-dependent density functional theory calculations?TD-DFT?on these two types of complexes.The theory and experiment are combined to provide an in-depth understanding of the characteristics of these two types of Ru₂complexes.The main research results are as follows:??Density Functional Theory Calculation of the Ru₂^?/?Ru₂O₂?CO₃?₂ESBO ComplexesDFT was used to calculate compounds Ru₂O₂?CO₃?₂?H₂O?₂?pip?₂?1??{M?H₂O?₄?OH?₂}₂Ru₂O₂?CO₃?₂[M=Mg?2?,Ni?3?],and energy level orbital diagrams,frontal molecular orbitals,metal-metal bond analysis,electronic spectroscopy?UV-Vis?,and electronic transitions were obtained.The highest occupied orbital?HOMO?of the compound?1?is?*_Ru-O,the lowest unoccupied orbital?LUMO?is?.The calculated Ru-Ru distance is 2.3806?,which is slightly smaller than the experimental value?2.38569??,and other bond lengths and bond angles are similar.NBO analysis revealed that metal-metal double bonds were formed between Ru atoms in this complex.In the compound?2?,HOMO is?*orbital and LUMO is?orbital.The solid structure of the complex was reproduced from the calculated bond length and bond angle.The information obtained by NBO analysis indicated that double bonds were formed between Ru atom.The electronic spectrum calculated by TD-DFT is helpful to analyze the ultraviolet absorption spectrum measured in the experiment,and to obtain the excitation and transition that cannot be obtained in the experiment.??Density Functional Theory Calculation of the Ru₂?PDP?₂X₂[X=Cl^-?4?,Br^-?5?] FSBO ComplexesThe density functional theory calculations of these two compounds,including geometric optimization,electronic structure,and electronic spectrum,were performed using two different computing methods B3LYP and BVP86.The front-line molecular orbitals of these two compounds have been listed in detail,they are both open-shell structures,and?and?are described separately.The analysis chart of the natural bond orbital provides the existence of a single bond between the Ru-Ru bonds of these two compounds.The spin density calculations indicate that the spin density of the two compounds is mainly distributed around Ru₂,the total spin density is 1,and the contribution of metal Ru atoms is the largest.Our calculations reproduce the electronic spectra of the compounds very well,and help to explain some experimental data that the ligand is halogen.