The Structures,Properties And Mechanism Of The Subgroup ? Metal Complexes

In this treatise, we have investigated several compounds of the Subgroup I metals which are of importance in orgnic syntheses and crystalline materials. We focused on the non-covalent interactions involved them by quantum chemical calculations. The main results are as follows:?1? An Au???X interaction has been predicted in the complexes between the organic gold compound RAu?R = CH₃, C₂H₃, and C₂H? and the organic halogen compound R'X?R' = CH₃, C₂ H, C₂H₃, and CF3; X = Cl, Br, and I? using quantum chemical calculations. Upon the basis of the anisotropic distribution of molecular electrostatic potentials on the Au and X atoms, two types of structures, represented as GB and XB, respectively, were obtained. In the GB structure, Au atom acts as a Lewis acid and X is a Lewis base, but the reverse roles are found for Au and X in XB. Interestingly, the former structure is far more stable than the latter one. Their differe nce in stability is regulated by the substitution and hybridization effects, similarly to those in hydrogen bonds. The partially covalent- interaction nature of GBs was characterized with the large charge transfer and the negative energy density as well as the high interaction energy. GB interaction is dominated by electrostatic and polarization energies, whereas electrostatic and dispersion energies are responsible for the stability of most XB complexes.?2? High- level quantum chemical calculations have bee n performed to investigate the influence of substituents on the metal···? interaction and its cooperative effect with halogen bond in C₂X₄···MCN···Cl F?X = H, CN, CH₃; M = Cu, Ag, Au?. The strong electron-withdrawing group CN weakens the metal···? covalent interaction, while the weak electron-withdrawing group CH₃ strengthens it. The metal···? covalent interaction is dominated by electrostatic energy although the Au CN complex has approximately equal electrostatic and polarization contributions. However, the metal···? covalent interaction is governed by polarization energy due to the CN substitution. A cooperative effect is found for the halogen bond and metal···? interactions in C₂H₄···MCN···Cl F, while a diminutive effect occurs in the triads by the CN substituent. Orbital interaction analysis indicates that the strong electron-withdrawing group CN causes the C=C group vary from a stronger donor orbital to a stronger acceptor orbital.?3? We investigated the interplay between the anion···? and coinage-metal···Lp interactions in the complexes involving three hetero-aromatic compounds of pyrazine, 1,4-dicyanobenzene and 1,4-benzoquinone. The physical nature of both interactions has been unveiled by means of molecular electrostatic potential and energy decomposition. Interesting cooperativity effects are observed when the anion···? and coinage-metal···Lp interactions coexist in the same multicomponent. These effects have been theoretically studied in terms of energetic and geometric features of the complexes as well as the charge transfer and orbital interactions. Weaker anion···? interaction shows a greater enhancement in the presence of stronger metal···Lp interaction.?4? The interplay between cation···? and coinage- metal···oxygen interactions are investigated in the ternary systems N···Ph CCM···O(N = Li⁺, Na+, Mg²⁺; M = Ag, Au; O = water, methanol, ethanol). A synergetic effect is observed when cation–p and coinage- metal···oxygen interactions coexist in the same complex. The cation···? interaction in most triads has a greater enhancing effect on the coinage- metal···oxygen interaction. This effect is analyzed in terms of the binding distance, interaction energy, and electrostatic potential in the complexes. Furthermore, the formation, strength, and nature of both the cation···? and coinage- metal···oxygen interactions can be understood in terms of electrostatic potential and energy decomposition.