Theoretical Studies Of The Interactions Between Guanine-uracil Base Pairs And Copper, Silver And Gold Using Density Functional Theory

In recent years,,the T-Hg₂^?-A base pair containing two equivalents of Hg???has been prepared and characterized experimentally.Its optical and high metal-ion load proterties mean a multi-application era of metal meidiated base pairs has begun.In this paper,the geometric and electronic structures,bonding proterties,and proton transfer processes of GUM₂^—/0/2+?G = guanine,U = uracil,M = Cu,Ag and Au?and GUAun?n = 1 – 10?were investigated using density functional approaches.The main research content of this paper is as follows: 1.The theoretical studies of dinuclear metal and guanine-uracil base pair: GUM₂^—/0?G = guanine,U = uracil,M = Cu,Ag and Au?using Density Function Theory Metal-mediated base pairs have received considerable attention in supramolecular chemistry and nanotechnology.In this paper,the geometric structures and bonding modes of the neutrally and negatively charged binuclear metal-mediated guanine-uracil base pairs were studied using density functional approaches.Guanine interacts with different isomers of uracil through stable hydrogen bonds,while a set of M₂ unit prefers to interact with N atoms in K-N9 H guanine in GUM₂.In anionic complexes,there is a weak interaction between M₂.N-H???M and C-H???M unconventional hydrogen bonds were formed.The bond order and AIM analyses show that the weak interactions between N···M and strong single bonds between M-M have been formed in neutrally charged GUM₂.Then,the structures of neutral GUCu₂ and GUAg₂ are stable through photoelectron spectroscopy and the structures of neutral GUAu₂ is instable.There's another way to do it through the experiment to verify this theory.2.Dinuclear Metal-Mediated Guanine-Uracil Base Pairs: Theoretical Studies of GUM₂²⁺?M = Cu,Ag and Au?Ions Dinuclear metal-mediated hetero base pairs with the d¹⁰-d¹⁰ closed-shellinteractions have significant stability.Geometric structures and energy of the lowest-lying isomers of GUM₂²⁺?G = guanine,U = uracil,M = Cu,Ag and Au?cluster ions were investigated with density functional theory.In the lowest-lying isomers of these dinuclear metal-mediated base pairs,the 2-oxo-4-hydroxy-trans-N1 H isomer of uracil is derived from the canonical tautomer of uracil by the hydrogen atom transfer.M₂²⁺ cations remain as an unbroken unit and interact with the G···U ligand through two sets of closely linear N-M-O units,while the reciprocal hydrogen bonds between the Wobble base pair?G–U?are entirely substituted by the M–N or M–O interactions in these complexes.The atoms in molecules and EDA–NOCV calculations really reveal that the ? interactions in GUM₂²⁺ cations are the paramount term of ?E_Orb.The obtained instantaneous interaction energies ?E_int and bond dissociation energies of the metal–ligand interactions give the trend of the bond strength as Cu?Au>Ag.3.The theoretical studies of gold cluster and guanine-uracil base pair: GUAu_n?n=1-10?using Density Function Theory The main purpose of this chapter was to analyze the electronic structure of gold cluster interacting with G·· U ligand and to establish a simple model based on density functional theory.In the lowest-nergy isomers of GUAun,when n?4?except n=2?,the gold clusters are prone to form a weak interaction with N3 and they lie in the same plane as guanine-uracil base pair.When 4<n?10?except n=9?,gold clusters are prone to form weak interaction with N7 and they together with guanine-uracil are noncoplanar.In this paper,the bond lengthes and electron binding energies show that the gold clusters exhibit strong electrophilic activities when these gold clusters were in the same plane as G···U,indicating that it may provide theoretical support for scientific experiments.