Ảnh hưởng của nhóm thế đến liên kết hiđro chuyển dời xanh trong các phức của sự tương tác giữa RCHO với CH3CHO (R = H, F, Cl, Br, CH3, NH2)

Abstract

Nine stable structures of the interactions between CH₃CHO and RCHO (R = H, F, Cl, Br, CH₃, NH₂) on the potential energy surface are obtained theoretically. Their interaction energies with both ZPE and BSSE corrections at the CCSD(T)/6-311++G(d,p)//MP2/6-311++G(d,p) level of theory range from -7.47 to -12.99 kJ.mol^-1. The substituents of one H atom in HCHO by one of halogens (F, Cl, Br) or CH₃ group, or NH₂ one make the strength of obtained complexes enhanced. In addition, the strength ordering of the complexes decreases in the order of the halogen (Br, Cl, F) derivatives via NH₂ group and finally to CH₃ group. The blue shifting of CH valence bond in the C-H∙∙∙O and C-H∙∙∙X (X = F, Cl, Br) hydrogen bonds decreases when replacing one H atom by one halogen atom, however it increases in the CH₃ and NH₂ derivative complexes. It is noteworthy that the blue shifting of CH bond in the various halogen-substituted complexes differs slightly.