Remarkable Blue Shifts of C−H and N−H Stretching Frequencies in the Interaction of Monosubstituted Formaldehyde and Thioformaldehyde with Nitrosyl Hydride

Abstract

Weak interactions of monosubstituted formaldehydes and thioformaldehydes with nitrosyl hydride were investigated by using ab initio MO calculations at the MP2/aug-cc-pVTZ level. Thirty two equilibrium structures having different complex forms were located on the corresponding potential energy surfaces (all having C(s) symmetry). Obtained binding energies, which include both ZPE and BSSE corrections, range from 7 to 14 kJ x mol(-1) and 6 to 12 kJ x mol(-1) for complexes of substituted formaldehydes and thioformaldehydes, respectively. In each geometrical structure, the (XCHO,HNO) complex is consistently more stable than the (XCHS,HNO) complex. The H-bond strength significantly increases when one H atom is replaced by a methyl group in both formaldehyde and thioformaldehyde. When replacing H by a halogen atom, the binding energy tends to decrease. It is remarkable that all the C-H and N-H bonds are shortened upon complexation, resulting in an increase of their stretching frequencies. Furthermore, the blue shifts are consistently observed for the interacting N-H bonds in N-H...X, Z, with X = F, Cl, Br, and Z = O, S; such contraction of a covalent N-H bond is extremely rare. In addition, the N-H bond length contraction and its frequency blue shift in the N-H...S complex have been revealed for the first time.

Computational investigations of HNO in biology

“…HNO can form various kinds of complexes with non-metal molecules, such as CO [31], HNO [32,33], HOX (X = F, Cl, Br, I) [34], CH 3 X (X = F, Cl, Br) [35], HFSO 2 [36], CH 3 CHO [37], HCONH 2 [38], XCHY (X = H, F, Cl, Br, CH 3 ; Y = O, S) [39], C 2 H 2 [40], HArF [41], and O 3 [42]. Based on the computational investigations, it is interesting to note that in these complexes, as long as the geometries allow, the most stable isomers prefer to involve both the terminal H and O atoms of HNO in the interactions, as illustrated in Fig.…”

Roles of H2O to hydrogen bonds, structure and strength of complexes of CH3CHS and H2O

“…Therefore, we want to have an insight into this issue in the complexes of CH3CHS with nH2O (n=1-3) and explain the role of water in hydrogen bonding to help us understand more about stability and the nature of H-bond in these systems, the effect of water on cooperativity and strength of complexes. The results will help contribute to shed more light on the origin of the C-H blue shifting Hbond and classification of H-bonds, [11,12,13] helping further to synthesize drugs for life and improving human health. [14] 2.…”

Understanding Interaction Capacity of CO2 with Organic Compounds at Molecular Level: A Theoretical Approach

“…In more recent investigations, the Lewis acid-base interaction between CO 2 and some carbonyl-functionalized compounds has been reported [34,44,[64][65][66][67]. The existence of the C─H•••O hydrogen bond in complexes was confirmed clearly by Wallen et al [38,39,60].…”