Metal Complexes Of The Weak Interaction In The Matter

Molecular recognitions based on all kinds of intermolecular weak interaction are the formation foundation of supermolecular compound constructed by the general chemical compound. For the coordination chemistry, weak interactions usually behave as either intraligand or interligand interaction in the metal complexes. So investigating the ligand-ligand interaction is an easy way to understand the supermolecular structure formed by coordination compounds. This thesis focuses on discussing intermolecular interaction in the metal complex and searches the relationship between the intermolecular interaction and the formation reasons of supermolecular coordination compound. The whole thesis consists of nine chapters, and is divided into four parts. Chapters 1-2 are the first section. Some concepts and current researches are concisely introduced, as well as the some questions it will be resolved in this work. Chapters 3-8 are the main research content of this text. Chapter 9 gives the conclusions.The research contents of this thesis is divided into three parts: In the first part (chapters 3-4), the stabilities of the ternary complexes of Copper(II) and Zinc(II) with amino acid and dipeptide are determined using the potentiometric titration experiments and theoretical calculation method. The crystal structure of copper complex with phenylalanyl-L-leuine is also reported. In the second part (chapter 5), the geometries of the ternary complexes of Copper(II) and Cadmium(II) with four substituted malonic acids and aromatic nitrogen-containing ligand are optimized with the MM+ method. Binding energies and relativity properties are calculated by the semiempirical ZINDO/1 method. The relationship between the complex structure and intermolecular interaction are discussed by the calculation results. In the third part (chapters 6-8), five transition metal complex structures are reported. Through the crystal structures of complex, the weak interactions, such as hydrogen bonding, aromatic stacking and CH interaction, are found to be very important to the supramolecular architectures. The brief outline is as follows:The formation arid stability constants of binary and ternary complexes of Copper(II) and Zinc(II) with dipeptide and amino acids have beendetermined by potentiometric pH titration at 25 C and an ionic strength of 0.10mol/L NaNOj in aqueous solution. The stability data show there are extra stabilities in all the ternary complexes. The possible reasons may be the weak interactions between the groups of ligand presented in the complexes, such as hydrogen bonding and hydrophobic interaction. It should be emphasized that the weak interactions may also take place in the ML type complex and the orientation of the side group of ligand could be changed by the configuration of the metal ion.The copper complex with phenylalanyl-L-leucine has been synthesized and crystal structure had also been determined by X-ray diffraction. It has been verified the results of solution experiments and observed that the conformation of PL dipeptide ligand had been changed in the coordination compound to favor the hydrophobic interaction between noncoordination side-groups of the dipeptide ligand. The intramolecular and intermolecular aromatic ring stacking and/or hydrophobic interactions presented extensively in the crystal structure of the complex and become the most important factor to stabilize the crystal structure. An ion channel exists in the crystal structure of the copper complex.The molecular geometries and binding energies of the Copper(II) and Zinc(II) complexes with amino acid and dipeptide were calculated by the semiempirical PM3 method. The theoretical calculation results show there are hydrogen bonding and hydrophobic interaction between the groups of ligand presented in the metal complexes. For the Copper(II) and Zinc(II) complexes, the differences of the extra stabilities of ternary complexes mainly come from the different coordination configurations of the central metal ion. The theoretical calculation results are s...