Computational study of the cooperative effects between tetrel bond and halogen bond in XCN⋅⋅⋅F2CO⋅⋅⋅YCN complexes (X = H,F, Cl,Br; Y = F,Cl, Br)

ABSTRACT

Ab initio calculations have been accomplished to study the cooperativity between the halogen bond and tetrel bond in the XCN???F2CO???YCN (X = H, F, Cl, Br; Y = F, Cl, Br) complexes. F₂CO at the same time plays the role of Lewis acid with the π-hole on the C atom and Lewis base with the O atom to participate in the tetrel bond and in halogen bond, respectively. According to the geometry survey, the effect of a tetrel bond on a halogen bond is more pronounced than that of a halogen bond on a tetrel bond and the intermolecular distances in the triads are always smaller than the corresponding values in the dyads. In all cases, the halogen bond and tetrel bond in the termolecular complexes are stronger compared with those in the bimolecular complexes. So, from the intermolecular distances, interaction energies and many-body interactions demonstrate that there is positive cooperativity between the halogen bond and tetrel bond. The molecular electrostatic potential, atoms in molecules and natural bond orbital methodologies are used to analyse the nature of interactions of the complexes.     

On difference of properties between organic fluorine hydrogen bond C–H···F–C and conventional hydrogen bond

The existence of C–H···F–C hydrogen bonds in the complexes of trifluoromethane and cyclic molecule (oxirane, cyclobutanone, dioxane, and pyridine) has been experimentally proven by Caminati and co-workers. This study presents a theoretical investigation on these C–H···F–C hydrogen bonds at B97D/6-311++G^** and MP2/6-311++G^** levels, in terms of C–H vibrational frequency shifts, atoms in molecules characteristics, and the bonding feature of C–H···F–C hydrogen bonds. It is found that in three important aspects, there are significant differences in properties between C–H···F–C and conventional hydrogen bonds. The C–H···F–C hydrogen bonds show a blueshift in the C–H vibrational frequencies, instead of the X–H normal redshift in X–H···Y conventional hydrogen bonds. The natural bond orbital (NBO) analyses show that σ and p types of lone pair orbitals of the F atom to an antibonding σ^*_H–C orbital form a dual C–H···F–C hydrogen bond. Such a dual hydrogen bonding leads to the proton acceptor directionality of the C–H···F–C hydrogen bond softer. Our studies also show that the Laplacian of the electron density (▽²ρ_BCP) is not always a good criterion for hydrogen bonds. Therefore, we should not recommend the use of the Laplacian of the electron density as a criterion for C–H···F–C hydrogen bonds.     

Cooperative effects between tetrel bond and other σ–hole bond interactions: a comparative investigation

Covalently bonded atoms of Groups IV–VII tend to have anisotropic charge distributions, the electronic densities being less on the extensions of the bonds (σ–holes) than in the intervening regions. These σ–holes often give rise to positive electrostatic potentials through which the atom can interact attractively and highly directionally with negative sites. In this work, cooperative effects between tetrel bond and halogen/chalcogen/pnicogen bond interactions are studied in multi-component YH₃M···NCX···NH₃ complexes, where Y = F, CN; M = C, Si and X = Cl, SH and PH₂. These effects are analysed in detail in terms of the structural, energetic, charge-transfer and electron density properties of the complexes. The nature of the σ–hole bonds is unveiled by quantum theory of atoms in molecules and natural bond orbital theory. A favourable cooperativity is found with values that range between ?0.34 and ?1.15 kcal/mol. Many-body decomposition of interaction energies indicate that two-body energy term is the most important source of the attraction, which its contribution accounts for 87%–96% of the total interaction energy.     

Theoretical study of cooperativity between hydrogen bond‒hydrogen bond,halogen bond‒halogen bond and hydrogen bond‒halogen bond in ternary FX…diazine…XF (X = H and Cl) complexes

ABSTRACT

In the present work, the cooperativity between hydrogen bond?hydrogen bond, halogen bond?halogen bond and hydrogen bond?halogen bond in ternary FX…diazine…XF (X = H and Cl) complexes is theoretically investigated. The sign of cooperative energy (E_coop) obtained in all of the triads is positive which indicates that the ternary complex is less stable than the sum of the two isolated binary complexes. Moreover, our calculations show that E_coop value in triads increases as FX…pyridazine…XF > FX…pyrimidine…XF > FX…pyrazine…XF. In agreement with energetic, geometrical and topological properties, electrostatic potentials and coupling constants across ¹⁵N…X?¹⁹F (X = ¹H or ³⁵Cl) hydrogen and halogen bonds indicate that hydrogen and halogen bonds are weakened in the considered complexes where two hydrogen and halogen bonds coexist. As compared to N…H hydrogen bond, it is also observed that cooperativity has greater effect on N…Cl halogen bond.     

Strengthening of the halogen-bonding by an aerogen bond interaction: substitution and cooperative effects in O3Z···NCX···NCY (Z = Ar,Kr, Xe; X = Cl,Br, I; Y = H,F, OH) complexes

The geometry, interaction energy and bonding properties of ternary complexes O₃Z···NCX···NCY (Z= Ar, Kr, Xe; X = Cl, Br, I and Y = H, F, OH) are investigated with ab initio calculations at the MP2/aug-cc-pVTZ level. Two different types of intermolecular interactions are present in these complexes, namely, aerogen bond (Z···N) and halogen bond (X···N). The formation mechanism and bonding properties of these complexes are analysed with molecular electrostatic potentials, quantum theory of atoms in molecules and non-covalent interaction index. It is found that the cooperativity energies in the ternary complexes are all negative; that is, the interaction energy of the ternary complex is greater (more negative) than the sum of the interaction energies of the corresponding binary systems. Also, the cooperativity energies increase with the increase of the interaction energies. The cooperative effects in the ternary complexes make a decrease in the total spin–spin coupling constants across the aerogen bonding, J(Z–N), which can be regarded as a proof for the reinforce of Z···N interactions in the ternary complexes with respect to the binary systems.     

Tuning of tetrel bonds interactions by substitution and cooperative effects in XH3Si···NCH···HM (X = H,F, Cl,Br; M = Li,Na, BeH and MgH) complexes

In this work, the interplay between the tetrel bond and the dihydrogen bond is investigated in ternary XH₃Si···NCH···HM complexes, where X = H, F, Cl, Br and M = Li, Na, BeH, MgH. The nature of Si···N and H···H interactions is studied by molecular electrostatic potential (MEP), noncovalent interaction and electron localisation function analyses. All binding distances in the ternary complexes are shorter than those of isolated XH₃Si···NCH and NCH···HM systems. That is, the two types of interactions have a cooperative effect on each other. The results of the MEP analysis indicate that the enhancement of the Si···N and H···H bonds can mainly be attributed to the electrostatic interaction. The plot of the reduced density gradient versus sign (λ₂)ρ indicates that the location of the spike associated with each interaction in the ternary systems moves slightly towards the negative (λ₂)ρ values with respect to the binary systems. This confirms that both Si···N and H···H interactions in the ternary complexes are strengthened by the presence of other. Besides, cooperative effects lead to a considerable change in the ¹⁴N nuclear quadrupole coupling constant values of the ternary complexes relative to the XH₃Si···NCH complexes.     

Cooperative interaction between π-hole and single-electron σ-hole interactions in O2S···NCX···CH3 and O2Se···NCX···CH3 complexes (X = F,Cl, Br and I)

Ab initio calculations are performed to analyse the cooperative effects between π-hole and single-electron σ-hole interactions in O₂S···NCX···CH₃ and O₂Se···NCX···CH₃ complexes, where X = F, Cl, Br and I. These effects are investigated in terms of geometric and energetic features of the complexes, which are computed by UMP2/aug-cc-pVTZ(-PP) method. Our results indicate that the shortening of the each π-hole bond distance in the complexes is dependent on the strength of the σ-hole interaction. The maximum and minimum energetic cooperativity values correspond to the most and least stable complexes studied in the present work. The cooperativity between both types of interaction is chiefly caused by the electrostatic effects. The topological analysis, based on the quantum theory of atoms in molecules, is used to characterise the interactions and analyse their enhancement with varying electron density at bond critical points.     

Competition between σ-hole pnicogen bond and π-hole tetrel bond in complexes of CF2=CFZH2 (Z = P,As, and Sb)

ABSTRACT

A computational study of the complexes formed by F₂C=CFZH₂ (Z?=?P, As, and Sb) and F₂C=CFPF₂ with two Lewis bases (NH₃ and NMe₃) has been carried out. In general, two minima complexes are found, one with a σ-hole pnicogen bond and the other one with a π-hole tetrel bond in most complexes but two σ-hole pnicogen bonded complexes are obtained for F₂C=CFZH₂ and NH₃. They have similar stability though F₂C=CFSbH₂ engages in a much stronger σ-hole pnicogen bond with NMe₃. The –PF₂ substitution makes the π-hole on the terminal carbon form a tetrel bond with NH₃. A heavier –ZH₂ group engages in a stronger σ-hole pnicogen bond but results in a weaker π-hole tetrel bond. Other than electrostatic interaction, the stability of both complexes is attributed to the charge transfer from the N lone pair into the C–Z/H–Z anti-bonding orbital in the pnicogen bond and the C=C anti-bonding orbital in the tetrel bond.

The σ-hole pnicogen bonded and π-hole tetrel bonded complexes between F₂C=CFZH₂ (Z = P, As, and Sb) and two Lewis bases (NH₃ and NMe₃) have been compared. The results indicate that both interactions can compete, dependent on the nature of the N base.     

Enhancement effect of lithium bonding on the strength of pnicogen bonds: XH2P···NCLi···NCY as a working model (X = F,Cl; Y = H,F, Cl,CN)

MP2 calculations with aug-cc-pVDZ basis set were used to analyse intermolecular interactions in XH₂P···NCLi···NCY triads (X = F, Cl; Y = H, F, Cl, CN) which are connected via pnicogen bond and lithium bond. To understand the properties of the systems better, the corresponding dyads are also studied. Molecular geometries and interaction energies of dyads, and triads are investigated at the MP2/aug-cc-pVDZ computational level. Particular attention is paid to parameters such as cooperative energies and many-body interaction energies. All studied complexes, with the simultaneous presence of a lithium bond and a pnicogen bond, show cooperativity with energy values ranging between ?4.73 and ?8.88 kJ mol^?1. A linear correlation was found between the interaction energies and magnitude of the product of most positive and negative electrostatic potentials. According to energy decomposition analysis, it is revealed that the electrostatic interactions are the major source of the attraction in the title complexes.     

The strengthening effect of a hydrogen or lithium bond on the Z···N aerogen bond (Z = Ar,Kr and Xe): a comparative study

An ab initio study is performed on O₃Z···NCM···NCX (Z = Ar, Kr and Xe; M = H and Li; X = H, F and CH₃) complexes to investigate cooperativity effects between aerogen and hydrogen or lithium bonding interactions in these systems. To understand the cooperative effects, a detailed analysis of the binding distances, interaction energies and bonding properties is performed on these complexes. The results indicate that all Z···N and H/Li···N binding distances in the ternary complexes are shorter than those of corresponding binary systems. For a given M or X, cooperative energies increase as Z = Xe > Kr > Ar. Moreover, O₃Z···NCLi···NCX complexes exhibit a larger cooperative energy than O₃Z···NCH···NCX ones. The non-covalent interaction (NCI) index analysis indicates that the formation of an H/Li···N interaction in the ternary complexes shifts the location of the spike associated with the Z···N interaction towards the negative λ₂ρ values. This indicates that NCI analysis can be regarded as a useful tool for the study of cooperative effects between two different non-covalent interactions. Also, cooperative effects in O₃Z···NCM···NCX complexes make a decrease in ¹⁴N nuclear quadrupole coupling constants of NCH or NCLi molecule.     

Cooperativity between the hydrogen bonding and halogen bonding in F3CX ··· NCH(CNH) ··· NCH(CNH) complexes (X=Cl,Br)

MP2 calculations with the cc-pVTZ basis set were used to analyse the intermolecular interactions in F₃CX?···?NCH(CNH)?···?NCH(CNH) triads (X=Cl, Br), which are connected via hydrogen and halogen bonds. Molecular geometries, binding energies, and infrared spectra of the dyads and triads were investigated at the MP2/cc-pVTZ computational level. Particular attention was given to parameters such as the cooperative energies, cooperative dipole moments, and many-body interaction energies. All studied complexes, with the simultaneous presence of a halogen bond and a hydrogen bond, show cooperativity with energy values ranging between ?1.32 and ?2.88?kJ?mol^?1. The electronic properties of the complexes were analysed using the Molecular Electrostatic Potential (MEP), electron density shift maps and the parameters derived from the Atoms in Molecules (AIM) methodology.     

A computational study of interplay between hydride bonding and cation–π interactions: H-Mg-H···X···Y triads (X = Li+, Na+, Y = C2H2, C2H4, C6H6) as model systems

In the present study, H-Mg-H···X···Y (X = Li⁺, Na⁺ and Y = C₂H₂, C₂H₄, C₆H₆) triads have been investigated at MP2/6-311++G(2d,2p) computational level to characterise cooperative effects between hydride bonding and cation–π interactions. Molecular geometries, binding energies, cooperative energies and many-body interaction energies were evaluated. The diminutive energy values in triads with Li⁺ are larger than respective values in triads with Na⁺. The electronic properties of the complexes are analysed using parameters derived from the quantum theory of atoms in molecules methodology.     

Mutual influence between covalent and noncovalent interactions in H3N–MCN–XF (X = H,Li, Cl,Br; M = Ag,Cu, Au)

The interplay between covalent and noncovalent interactions has been investigated in H₃N–MCN–XF (X = H, Li, Cl, Br; M = Ag, Cu, Au) complexes using ab initio calculations at the MP2 level of theory. The coinage metal as a substituent has an irregular enhancing effect (Au < Cu < Ag) on the strength of noncovalent interaction in MCN–XF, while the covalent interaction in H₃N–MCN becomes stronger with the reverse order. Interesting cooperativity effects were observed when covalent and noncovalent interactions coexist in the same complex, and they become more prominent for the stronger covalent and noncovalent interactions. These effects have been characterised in detail with the structural, spectroscopic, energetic, and charge transfer features of the complexes.     

Metal hydrides as sodium bond acceptors: hydride-sodium bond in the XH ··· NaH (X = HBe,LiBe, NaBe,HMg, LiMg,and NaMg) complexes

New kinds of sodium bonding complexes XH?···?NaH (X?=?HBe, LiBe, NaBe, HMg, LiMg, and NaMg) have been predicted and characterized in the present paper. For each XH?···?NaH complex, the hydride-sodium bond is formed between the negatively charged H atom of XH and the positively charged Na atom of NaH. Due to the formation of the complexes, both the X–H and the Na–H bonds are elongated, and the Na–H stretching vibrational frequency is redshifted. The interaction energies in the XH?···?NaH complexes at the MP2/6-311++G(3df, 3pd) level increased in the order: HBeH?···?NaH (?4.50?kcal/mol)?相似文献   

超越F=ma

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Prediction of binding bond energy between phosphorous-based ionic liquids and CO2. Assessment of the CO2–anion interactions

The absorption of carbon dioxide (CO₂) in phosphorous-based ionic liquids was studied theoretically by the molecular modeling ab initio density functional theory (dispersion-corrected B3LYP) and second-order M?ller-Plesset perturbation methods. Several types of phosphate- and phosphite-based anions were employed and the calculation results were compared with recent published papers. The interaction energy between CO₂ and anion, following the result of Bhargava and Balasubramanian, was calculated in order to have a better understanding on the effect of different functional groups on the interaction between CO₂ and anion. The computational results indicated that the molar volume of the anion molecules played an important role on the absorption mechanism of CO₂ due to the CO₂-philicity of carbonyl and alkyl groups.     

The triel bond: a potential force for tuning anion–π interactions

Using ab-initio calculations, the mutual influence between anion–π and B···N or B···C triel bond interactions is investigated in some model complexes. The properties of these complexes are studied by molecular electrostatic potential, noncovalent interaction index, quantum theory of atoms in molecules (QTAIM) and natural bond orbital (NBO) analyses. According to the results, the formation of B···N or B···C triel bond interactions in the multi-component systems makes a significant shortening of anion–π distance. Such remarkable variation in the anion–π distances has not been reported previously. The strengthening of the anion–π bonding in the multi-component systems depend significantly on the nature of the anion, and it becomes larger in the order Br^? > Cl^? > F^?. The parameters derived from the QTAIM and NBO methodologies are used to study the mechanism of the cooperativity between the anion–π and triel bond interactions in the multi-component complexes.     

Computational study of non-covalent interactions in oxirane…XF complexes (X = H,F, Cl,Br, Li) and their F-/Li-substituted analogues

A computational study found oxirane^…XF (X = H, Cl, Br, F, Li) dimers to be energetically stable, with their interaction energies increasing with the magnitude of the XF dipole moment in the order XF = LiF > BrF ～ HF > ClF > F₂. Their relative stabilities roughly correlate with the amount of charge transferred from the lone pairs on the O atom of oxirane to the antibonding σ* orbital of XF. However, the most strongly bound dimer, oxirane^…LiF, is stabilised by the largest dipole but involves the smallest charge transfer. The variation in the strength of the oxirane^…XF interaction was subsequently investigated by the sequential substitution of the protons on oxirane by either electron-donating Li or electron-withdrawing F atoms.     

Delocalized π state between molecules through a surface confined pseudodihydrogen bond

When 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) and coronene molecules coadsorb on the Ag(111) surface, one-dimensional PTCDA molecular oligomers with efficient electronic connection via noncovalent bonds are observed by low temperature scanning tunneling microscopy. Density functional theory calculations indicate the neighboring PTCDA molecules form oligomers due to strong PTCDA-metal interactions, which result in overlapping of π orbitals and pseudodihydrogen surface bonds between molecules. Our results provide a potential approach for electron transport from molecule to molecule directly through noncovalent bond.