Speciation of Copper鈥揚eptide Complexes in Water Solution Using DFTB and DFT Approaches: Case of the [Cu(HGGG)(Py)] Complex

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• 作者：Maurizio Bruschi ; Luca Bertini ; Vlasta Bona膷i膰-Kouteck媒 ; Luca De Gioia ; Roland Mitri膰 ; Giuseppe Zampella ; Piercarlo Fantucci
• 刊名：The Journal of Physical Chemistry B
• 出版年：2012
• 出版时间：June 7, 2012
• 年：2012
• 卷：116
• 期：22
• 页码：6250-6260
• 全文大小：401K
• 年卷期：v.116,no.22(June 7, 2012)
• ISSN：1520-5207

文摘

The DFTB and DFT methods are applied to the study of different forms of the [Cu(HGGG)(Py)] complex in water, with the aim of identifying the most stable isomer. The DFTB calculations were possible thanks to a careful parametrization of the atom鈥揳tom repulsive energy terms for Cu鈥揌, Cu鈥揅, Cu鈥揘, and Cu鈥揙. The speciation process is carried out by computing different DFTB-steered molecular dynamics (SMD) trajectories, each of which ends in a well-defined different form. The last frame of each trajectory is subjected to geometry optimization at both DFTB and DFT levels, leading to a different isomer. From the corresponding energy values, a rank of relative stability of the isomers can be established. The computational protocol developed here is of general applicability to other metal鈥損eptide systems and represents a new powerful tool for the study of speciation of metal-containing systems in water solution, particularly useful when the full characterization of the compound cannot be carried out on the basis of experimental results only.