Hydrogen Bond Critical Points Research Articles

A refreshing approach to understanding the action on DNA of vanadium (IV) and (V) complexes derived from the anticancer VCp2Cl2

A computational study based on derivatives of the anticancer VCp2Cl2 compound and their interaction with representative models of deoxyribonucleic acid (DNA) is presented. The derivatives were obtained by substituting the cyclopentadienes of VCp2Cl2 with H2O, NH3, OH−, Cl−, O2− and C2O42− ligands. The oxidation states IV and V of vanadium were considered, so a total of 20 derivative complexes are included. The complexes interactions with DNA were studied using two different models, the first model considers the interactions of the complexes with the pair Guanine-Cytosine (G-C) and the second involves the interaction of the complexes with adjacent pairs, that is, d(GG). This study compares methodologies based on density functional theory with coupled cluster like calculations (DLPNO-CCSD(T)), the gold standard of electronic structure methods. Furthermore, the change in the electron density of the hydrogen bonds that keep bonded the G-C pair and d(GG) pairs, due to the presence of vanadium (IV) and (V) complexes is rationalize. To this aim, quantities obtained from the topology of the electron densities are inspected, particularly the value of the electron density at the hydrogen bond critical points. The approach allowed to identify vanadium complexes that lead to significant changes in the hydrogen bonds indicated above, a key aspect in the understanding, development, and proposal of mechanisms of action between metal complexes and DNA.

Evaluation of the electronic density at critical points of hydrogen bonds: PM7 a good alternative to ab‐initio methods

AbstractHydrogen bonds are of vital importance in the formation and functioning of organic molecules; their characterization with theoretical tools is a task of interest to the scientific community. Commonly, the electron density at the bond critical point is used to characterize bonds. Generally this task is carried out with ab‐initio methods. In this study, the PM7 semi‐empirical approach is used to evaluate the quality of the electron density at the hydrogen bond critical points (HBCPs). The research takes into account dimers, nucleobases and alpha‐helices bonded by hydrogen bonds: , , , , , and . The results are compared with second‐order Møller–Plesset and density functional theory. The findings demonstrate that PM7 is a reliable alternative for explaining the electron density trends at the HBCPs.

Quantification of hydrogen bond energy based on equations using spectroscopic, structural, QTAIM-based, and NBO-based descriptors which calibrated by the molecular tailoring approach

ContextHydrogen bonds critically influence the structure and properties of both organic molecules and biomolecules, as well as supramolecular assemblies. For this reason, the development and elaboration of methods for quantitative assessment of hydrogen bond energy is an urgent challenge. In this study, using a large series of hydroxycarbonyl aliphatic compounds with the O‒H···O = C intramolecular hydrogen bond, a bank of hydrogen bond descriptors was created, including spectroscopic, structural, QTAIM-based, and NBO-based parameters. It was shown that the O‒H vibration frequency, OH chemical shift as the spectroscopic descriptors, the O···H hydrogen bond length, O···O distance, and O‒H covalent bond length as the structural descriptors, the electron density and its Laplacian, electron potential energy density in the hydrogen bond critical point, the electron density at the ring critical point as the QTAIM-based descriptors change in a correlated manner. The same correlation is found in change of the charge transfer energy through a hydrogen bond, the occupancy of the O‒H bond antibonding orbital, the Wiberg indices of the O···H hydrogen bond, and the O‒H covalent bond, as well as the polarization of the O‒H bond, which are the NBO-based descriptors. It was also recognized that the specified descriptors from the spectroscopic, structural, QTAIM-based, and NBO-based categories are functionally related to the values of intramolecular hydrogen bond energy, quantified via the molecular tailoring approach. This allowed one to obtain a system of equations for quantitative estimation of intramolecular hydrogen bond energy based on the spectroscopic, structural, QTAIM, and NBO descriptors, which makes such quantification more dependable and reliable.MethodsTo obtain the spectroscopic descriptors, the vibrational spectra and shielding constants were calculated using the GIAO method. Structural descriptors were obtained for the equilibrium geometry of molecules, calculated at the MP2(FC)/6–311 + + (2d,2p) level using the Gaussian 09 program. The QTAIM-based descriptors were calculated using the AIMAll program within the framework of the quantum theory “Atoms in Molecules.” The NBO-based descriptors were calculated using the NBO 3.1 program implemented into Gaussian 09. To quantify the energy of intramolecular hydrogen bonds, molecular fragmentation was used within the molecular tailoring approach.

Analysis of the Electron Density of a Water Molecule Encapsulated by Two Cholic Acid Residues

Cholic acid is a trihydroxy bile acid with a nice peculiarity: the average distance between the oxygen atoms (O7 and O12) of the hydroxy groups located at C7 and C12 carbon atoms is 4.5 Å, a value which perfectly matches with the O/O tetrahedral edge distance in Ih ice. In the solid phase, they are involved in the formation of hydrogen bonds with other cholic acid units and solvents. This fact was satisfactorily used for designing a cholic dimer which encapsulates one single water molecule between two cholic residues, its oxygen atom (Ow) being exactly located at the centroid of a distorted tetrahedron formed by the four steroid hydroxy groups. The water molecule participates in four hydrogen bonds, with the water simultaneously being an acceptor from the 2 O12 (hydrogen lengths are 2.177 Å and 2.114 Å) and a donor towards the 2 O7 (hydrogen bond lengths are 1.866 Å and 1.920 Å). These facts suggest that this system can be a nice model for the theoretical study of the formation of ice-like structures. These are frequently proposed to describe the water structure found in a plethora of systems (water interfaces, metal complexes, solubilized hydrophobic species, proteins, and confined carbon nanotubes). The above tetrahedral structure is proposed as a reference model for those systems, and the results obtained from the application of the atoms in molecules theory are presented here. Furthermore, the structure of the whole system allows a division into two interesting subsystems in which water is the acceptor of one hydrogen bond and the donor of another. The analysis of the calculated electron density is performed through its gradient vector and the Laplacian. The calculation of the complexation energy used correction of the basis set superposition error (BSSE) with the counterpoise method. As expected, four critical points located in the H…O bond paths were identified. All calculated parameters obey the proposed criteria for hydrogen bonds. The total energy for the interaction in the tetrahedral structure is 54.29 kJ/mol, while the summation obtained of the two independent subsystems and the one between the alkyl rings without water is only 2.5 kJ/mol higher. This concordance, together with the calculated values for the electron density, the Laplacian of the electron density, and the lengths of the oxygen atom and the hydrogen atom (involved in the formation of each hydrogen bond) to the hydrogen bond critical point, suggests that each pair of hydrogen bonds can be considered independent of each other.

Water-dispersible polymer coated silica nanoparticle for turn-on fluorometric detection of Cephalexin

Nanostructured molecular imprinted polymer for the sensitive and selective fluorometric detection of Cephalexin has been developed using a core-shell imprinting technology. The polymer coat on silica nanoparticles acquires a large surface area to adsorb the analytes. A hydrophilic functional monomer N-[Tris(hydroxymethyl)methyl]acrylamide and crosslinker ethylene glycol dimethylacrylate were used to synthesize the imprinted polymer to enhance the water dispersibility. The imprinted polymer was characterized with FTIR, FESEM and HRTEM. The diameter of the imprinted polymer appears to be ∼200–500 nm size. An environment-sensitive coumarin-based fluorescent monomer was integrated into the polymer as a signaling unit. The polymer shows a turn-on emission behaviour upon adsorption of Cephalexin on the surface. The limit of detection of Cephalexin is 1.6 μM. The imprinted polymer efficiently detects the drug molecule in synthetic urine samples also. The interaction of the monomer and the drug molecules was further supported with the optimized geometries, electron density calculation at the hydrogen bond critical points, and reduced density gradient (RDG) analysis calculated at ωB97X-D/6-311 + G(d,p) level of theory.

Understanding Hydrogen Bonding Effects on the Reversibility and Redox Potential of Redox Organic Molecules in Deep Eutectic Solvents

Deep eutectic solvent (DES) systems offer unique properties as electrolytes for redox flow batteries. They consist of hydrogen bond donor and acceptor pairs and often offer larger electrochemical windows than traditional aqueous electrolytes with lower vapor pressure than other non-aqueous systems like acetonitrile. They can contain a large concentration of charge carries and have the potential to be high energy density electrolytes1. When paired with redox organic species it is possible to tune both the electrolyte and redox actives to obtain desirable electrochemical properties such as the solubility of active species, kinetic and transport behaviors and even thermodynamic properties such as redox potential2. When attempting to understand these behaviors in DES it becomes important to understand the redox organic molecule’s interaction with the hydrogen bond network. For example, it has been show that altering the ratio of hydrogen bond donor to acceptor sites in a molecule can have dramatic effects on its solubility3. Hydrogen bonding between the DES and the redox organic in its varying charge states can dramatically impact many aspects of the electrochemical behavior.This work focuses on interactions that can have apparent effects on the kinetic and thermodynamic behavior of redox organics. We explore several molecules such as viologen derivatives, PTIO and N-methyl-phthalimide, some of which exhibit reversible behavior in both acetonitrile and a choline chloride and ethylene glycol based DES while other do not. Some see a dramatic shift in redox potential while other do not. We correlate these changes in behavior to influences of hydrogen bonding through the use of IR spectroscopy paired with voltammetry. Red shift in the stretching frequencies of redox active functional groups indicates the presence or lack of hydrogen bonding and this is related to changes in voltammetry as ethylene glycol, a hydrogen bond donor, is added to the redox organic in acetonitrile electrolyte system. It was observed that radical/cation reactions such as PTIO/PTIO+ or viologen were unaffected both kinetically and thermodynamically while reactions involving anionic species such as PTIO-/PTIO or N-methyl-phthalimide would either become irreversible or shift potential. This can be observed for PTIO in the accompanying figure where the cation reaction (more positive couple) does not change while the anion reaction (more negative couple) changes potential dramatically. We propose that some anionic species hydrogen bond more strongly at the redox active sites due to their higher electron density at a hydrogen bond critical point. Electron density has been strongly correlated to hydrogen bond strength4 and molecular modeling is being done to determine the comparative hydrogen bond strength of the anion and cation species as well as reversible and irreversible cationic species. These insights can lead to the intelligent design of highly soluble redox species that remain reversible and make use of the full electrochemical window of a given DES. E. L. Smith, A. P. Abbott and K. S. Ryder, Chem. Rev., 114, 11060–11082 (2014).N. S. Sinclair, D. Poe, R. F. Savinell, E. J. Maginn and J. S. Wainright, J. Electrochem. Soc., 168, 020527 (2021).B. Chen, S. Mitchell, N. Sinclair, J. Wainright, E. Pentzer and B. Gurkan, Mol. Syst. Des. Eng., 5, 1147–1157 (2020).G. Gilli and P. Gilli, J. Mol. Struct., 552, 1–15 (2000). Figure 1

An explanation of the unusual strength of the hydrogen bond in small water clusters

AbstractWe seek to explain why the hydrogen bond possesses unusual strength in small water clusters that account for many of the complex behaviors of water. We have investigated and visualized the donation of covalent character from covalent (sigma) to hydrogen bonds by calculating the eigenvector coupling properties of quantum theory of atoms in molecules (QTAIM), stress tensor σ(r), and Ehrenfest Force F(r) on the F(r) molecular graph. The next‐generation three‐dimensional (3‐D) bond‐path framework sets are presented, and only the F(r) bond‐path framework sets reproduce the earlier finding on the coupling between covalent (sigma) and hydrogen bonds that possess a degree of covalent character. Exploration of the bond‐path between the covalent (sigma) and hydrogen bond's critical points provides an explanation for the previously obtained coupling results. The directional character of the covalent (sigma) and hydrogen bonds' 3‐D bond‐path framework sets for the F(r) explains differences found in the earlier results from QTAIM and the stress tensor σ(r).

Investigation of bound and unbound phosphoserine phosphatase conformations through elastic network models and molecular dynamics simulations

The human phosphoserine phosphatase (hPSP) catalyses the last step in the biosynthesis of L-serine. It involves conformational changes of the enzyme lid once the substrate, phosphoserine (PSer), is bound in the active site. Here, Elastic Network Model (ENM) is applied to the crystal structure of hPSP to probe the transition between open and closed conformations of hPSP. Molecular Dynamics (MD) simulations are carried out on several PSer-hPSP systems to characterise the intermolecular interactions and their effect on the dynamics of the enzyme lid. Systems involving either Ca++ or Mg++ are considered. The first ENM normal mode shows that an open-closed transition can be explained from a simple description of the enzyme in terms of harmonic potentials. Principal Component Analyses applied to the MD trajectories also highlight a trend for a closing/opening motion. Different PSer orientations inside the enzyme cavity are identified, i.e. either the carboxylate, the phosphate group of PSer, or both, are oriented towards the cation. The interaction patterns are analysed in terms of hydrogen bonds, electrostatics, and bond critical points of the electron density distributions. The latter approach yields a global description of the bonding intermolecular interactions. The PSer orientation determines the content of the cation coordination shell and the mobility of the substrate, while Lys158 and Thr182, involved in the reaction mechanism, are always in interaction with the substrate. Closed enzyme conformations involve Met52-Gln204, Arg49-Glu29, and Arg50-Glu29 interactions. Met52, as well as Arg49 and Arg50, also stabilize PSer inside the cavity. Communicated by Ramaswamy H. Sarma

Electronic substituent effect on Se-H⋯N hydrogen bond: A computational study of para-substituted pyridine-SeH2 complexes

Complexes between para-substituted pyridine and SeH2 have been investigated at the MP2/aug-cc-pVTZ level. Various electron donating and withdrawing substituents (-NH2, -OH, -CH3, -H, -F, -Cl, -CN, and -NO2) are chosen in order to characterize their influence on Se-H⋯N intermolecular hydrogen-bonding interaction. The electron donating substituents lead to an increase of the stabilization energy along with elongation in the Se-H bond length and red-shift in Se-H stretching frequency. Conventional electronic substitution effect has been observed on various hydrogen-bond parameters, such as, stabilization energy, change in Se-H bond length and stretching frequency, charge transfer, bond order, electron density at hydrogen-bond critical point.

Electron Density, Interaction Energy and Hydrogen-Bond Radius of C–H...O Interaction

Atoms in theoretical analysis of molecules was used to study C–H...O interaction taking five different molecules with the same acceptor, O of water. The relation between electron density at hydrogen-bond critical point and interaction energy has been studied and hydrogen-bond radii were derived. Although a linear relationship was obtained like other intermolecular interactions, the value of linear parameters was found to be different when a similar type of interaction was compared suggesting that the parameters depend on the type of acceptor and donor and not the type of interaction. The H-bond radii for this type of interaction were found to have significant variance.

Systematic Characterization of Gas Phase Binary Pre-Nucleation Complexes Containing H2SO4 + X, [ X = NH3, (CH3)NH2, (CH3)2NH, (CH3)3N, H2O, (CH3)OH, (CH3)2O, HF, CH3F, PH3, (CH3)PH2, (CH3)2PH, (CH3)3P, H2S, (CH3)SH, (CH3)2S, HCl, (CH3)Cl)]. A Computational Study.

A systematic characterization of gas phase binary prenucleation complexes between H2SO4 (SA) and other molecules present in the atmosphere (NH3, (CH3)NH2, (CH3)2NH, (CH3)3N, H2O, (CH3)OH, (CH3)2O, HF, CH3 F, PH3, (CH3)PH2, (CH3)2PH, (CH3)3P, H2S, (CH3)SH, (CH3)2S, HCl, (CH3)Cl) has been carried out using the ωB97X-D/6-311++(2d,2p) method at the DFT level of theory. A relationship between the energy gap of the SA's LUMO and the partner molecule's HOMO, and the increasing number of methyl groups -CH3 in the SA's partner molecule is provided. The binding energies of the bimolecular complexes are found to be related to the electron density in the hydrogen bond critical point, the HOMO-LUMO energy gap, the nature of the hydrogen acceptor atom, and the frequencies shift of acid OH bonds. The results show how the frontier orbital compatibility determines the binding energy and that the properties of SA's OH bond which remains free of interactions are affected by the bimolecular adduct formation.

A DFT Study of the Geometrical, Spectroscopical and Reactivity Properties of Diindolylmethane-Phenylboronic Acid Hybrids.

The structure of the ortho-, meta- and para- hybrid diindolylmethane-phenylboronic acids and their interactions were optimized with by a quantum chemical method, using density functional theory at the (DFT) level. Thus, infrared bands were assigned based on the scaled theoretical wavenumbers by correlating the respective experimental data of the molecules. In addition, the corresponding 1H-/13C-/11B-NMR experimental and theoretical chemical shifts were correlated. The target molecules showed a poor treatment of the OH shifts in the GIAO method due to the absence of explicit solvent effects in these calculations; therefore, they were explicitly considered with acetone molecules. Moreover, the electron density at the hydrogen bond critical point increased, generating stabilization energy, from weak to moderate or weak to strong, serving as an indicator of the strength of the hydrogen bond between the different intermolecular interactions. Finally, some properties related to the reactive behavior of the target molecules associated with their cytotoxic effects and metabolic pathways were also calculated.

Theoretical Study of Intramolecular Interactions in Peri-Substituted Naphthalenes: Chalcogen and Hydrogen Bonds.

A theoretical study of the peri interactions, both intramolecular hydrogen (HB) and chalcogen bonds (YB), in 1-hydroxy-8YH-naphthalene, 1,4-dihydroxy-5,8-di-YH-naphthalene, and 1,5-dihydroxy-4,8-di-YH-naphthalene, with Y = O, S, and Se was carried out. The systems with a OH:Y hydrogen bond are the most stable ones followed by those with a chalcogen O:Y interaction, those with a YH:O hydrogen bond (Y = S and Se) being the least stable ones. The electron density values at the hydrogen bond critical points indicate that they have partial covalent character. Natural Bond Orbital (NBO) analysis shows stabilization due to the charge transfer between lone pair orbitals towards empty Y–H that correlate with the interatomic distances. The electron density shift maps and non-covalent indexes in the different systems are consistent with the relative strength of the interactions. The structures found on the CSD were used to compare the experimental and calculated results.

Effect of ionic charge on O[formula omitted]H⋯Se hydrogen bond: A computational study

Complexes between para-substituted cationic phenol and SeH2 have been investigated in electronic ground state at the B3LYP, B3PW91, and ωB97xD levels of theory using 6-311++G(3df,3pd) basis set. Various electron-donating and withdrawing substituents (NH2, OH, CH3, H, F, Cl, CN, and NO2) are used to characterize electronic substituent effect on intermolecular +OH⋯Se hydrogen bond. Electron withdrawing substituent increases hydrogen bond stabilization energy and red shift in OH stretching frequency. Introduction of a positive charge transforms weak hydrogen bond of neutral OH⋯Se type into a strong hydrogen bond. Complexation induced changes on various hydrogen bond parameters, such as, stabilization energy, change in OH bond length, change in OH stretching frequency, extent of charge transfer from hydrogen bond acceptor to donor, hydrogen bond orders, electron density at the hydrogen bond critical point exhibit conventional electronic substitution effect. Stabilization energy of +OH⋯Y hydrogen bond are similar in the complexes between cationic phenol and SH2/SeH2, whereas it is almost twice with OH2 in case of +OH⋯Y hydrogen bond.

The influence of CH…π interaction on hydrogen bonding ability of –CONH2 functional group of benzamide

Interplay between CH…π and hydrogen bond interactions of benzamide has been investigated by quantum mechanical calculations. The effect of the substituents on geometrical parameters has also been studied at the B3LYP level with 6-311++G(d,p) basis set. The electron-withdrawing substituents enhance the total interaction energy of the complexes. The results indicated that the cooperativity of interactions leads to extra stability of the ternary complexes. The CH…π interaction and the hydrogen bond energies have been estimated using the electron densities calculated by the atoms in molecules (AIM) method at hydrogen bond critical points. The strength of hydrogen bonding increases in the presence of CH…π interaction in the ternary complexes. The effect of CH…π interaction on the hydrogen bond interaction has also been studied by the natural bond orbital, AIM and the molecular electrostatic potential analyses.

Estimating the energy of intramolecular hydrogen bonds from 1H NMR and QTAIM calculations.

The values of the downfield chemical shift of the bridge hydrogen atom were estimated for a series of compounds containing an intramolecular hydrogen bond O-HO, O-HN, O-HHal, N-HO, N-HN, C-HO, C-HN and C-HHal. Based on these values, the empirical estimation of the hydrogen bond energy was obtained by using known relationships. For the compounds containing an intramolecular hydrogen bond, the DFT B3LYP/6-311++G(d,p) method was used both for geometry optimization and for QTAIM calculations of the topological parameters (electron density ρBCP and the density of potential energy V in the critical point of the hydrogen bond). The calculated geometric and topological parameters of hydrogen bonds were also used to evaluate the energy of the hydrogen bond based on the equations from the literature. Comparison of calibrating energies from the 1H NMR data with the energies predicted by calculations showed that the most reliable are the linear dependence on the topological ρBCP and V parameters. However, the correct prediction of the hydrogen bond energy is determined by proper fitting of the linear regression coefficients. To obtain them, new linear relationships were found between the calculated ρBCP and V parameters and the hydrogen bond energies obtained from empirical 1H NMR data. These relationships allow the comparison of the energies of different types of hydrogen bonds for various molecules and biological ensembles.

The effect of hydrogen bond strength on emission properties in 2-(2′-hydroxyphenyl)imidazo[1,2-a]pyridines

Abstract The correlation between the structures and molecular properties on the one hand and the fluorescence properties on the other for a set of 2-(2′-hydroxyphenyl)imidazo[1,2- a ]pyridines exhibiting excited-state intramolecular proton transfer (ESIPT) was analyzed via comparison of the optical data and computational results. Ab initio calculations were used to characterize the electronic transitions of 2-(2′-hydroxyphenyl)imidazo[1,2- a ]pyridine and its three derivatives both in non-polar and polar solvents by using DFT and TDDFT methods and the IEFPCM model. The calculations involving geometry optimization in the excited state allow to precisely predict the emission wavelength from the excited keto state. We constructed and studied the correlations between the positions of the emission maximum for the compounds considered and the hydrogen bond energies values for ρ ( r ) and ▽ 2 ρ ( r ) at the hydrogen bond critical point and the aromaticity of chosen structural fragments. It was found that the fluorescence properties of ESIPT molecules could be manipulated by directed modification of their chemical structure, most importantly by the introduction of electron-withdrawing functionalities into their proton donor moieties. The electron-withdrawing CN group hypsochromically shifts the emission from the keto excited state by ∼60 nm and strengthens at the same time the intramolecular hydrogen bond.

Physical meaning of the QTAIM topological parameters in hydrogen bonding.

This work examined the local topological parameters of charge density at the hydrogen bond (H-bond) critical points of a set of substituted formamide cyclic dimers and enolic tautomers. The analysis was performed not only on the total electron density of the hydrogen bonded complexes but also on the intermediate electron density differences derived from the Morokuma energy decomposition scheme. Through the connection between these intermediate electron density differences and the corresponding differences in topological parameters, the meaning of topological parameters variation due to hydrogen bonding (H-bonding) becomes evident. Thus, for example, we show in a plausible way that the potential energy density differences at the H-bond critical point properly describe the electrostatics of H-bonding, and local kinetic energy density differences account for the localization/delocalization degree of the electrons at that point. The results also support the idea that the total electronic energy density differences at the H-bond critical point describe the strength of the interaction rather than its covalent character as is commonly considered.

A study of intramolecular hydrogen bonds C-H⋯X (X = N, O) within the theory of the electron localization function

Electron localization functions (ELFs) are calculated at the hydrogen bond critical points for a number of molecules having the intramolecular hydrogen bond C-H⋯X (X = N, O). It is shown that the values of the core and valence electrons bifurcation index (CVBI) are positive in all cases. This enables the characterization of the studied hydrogen bonds as weak interactions of mainly electrostatic nature. For stronger intramolecular hydrogen bonds N-H⋯O with a significant contribution of covalence to the bonding, the bifurcation index is negative. A relationship between the parameters calculated within the theory of the electron localization function (ELF) and the quantum theory “Atoms in Molecules” (QTAIM) is observed. In the 1H NMR spectra, the resonance shift of the bridging hydrogen atom, induced by a hydrogen bond is much smaller for the hydrogen bonds having a positive bifurcation index than that for the hydrogen bonds with the negative bifurcation index, and the interatomic H⋯X distance is much longer in the former case. In the IR spectra the positive bifurcation index corresponds to a blue shift of the stretching vibration of the covalent bond of the hydrogen donor due to the hydrogen bonding and the negative bifurcation index corresponds to the red shift of this band.

The hydrogen bond interactions in glycine–nitrosamine complexes: a DFT study

The strong and directional hydrogen bonding interaction between glycine (G) and nitrosamine (NA) have been investigated using B3LYP and B3PW91 methods with a wide range of basis sets. With four preferential interaction sites in the vicinity of the glycine, eight different conformations (GNA1-8) with two intermolecular hydrogen bonds [NHNA···N(O)G and O(N)NA···HXG (X = O, N, C)] were found on the potential energy surface. The influence of the hydrogen bond on the molecular and topological properties, as well as nuclear magnetic resonance one- and two-bond spin–spin coupling constants in the gas phase was investigated. The most stable complexes labeled GNA1 and GNA2 are formed in S1 site. Natural bond orbital analysis shows that in the most stable complexes GNA1 and GNA2 the charge transfer takes place from NA to G, whereas, the reverse happens in other complexes. The results predict that in all complexes, the LPO(N)NA → σ*(X–H)Gly (X = O, N, C) and LPN(O)Gly → σ*(N–H)NA donor–acceptor interactions are the most important interactions. Atom in molecule analysis confirms that all hydrogen bonds have partially covalent nature. The covalent nature of proton donor groups decreases upon complexation. The relationship between spin–spin coupling constant (1h JH···Y and 2h JH···Y) with interaction energy and electronic density at corresponding hydrogen bond critical points and H-bonds distances are investigated.