A novel definition for the hydrogen bond is recommended here. It takes into account theoretical and experimental knowledge acquired over past century. This insists on some evidence. Six criteria are listed that could be used as evidence presence of a bond.

The topological and energetic properties of the electron density distribution ρ(r) isolated pairwise H⋯F interaction have been theoretically calculated at several geometries (0.8<d<2.5 Å) represented against corresponding internuclear distances. From long to short geometries, results presented here lead three characteristic regions, which correspond different states. While extreme regions are associated pure closed-shell (CS) shared-shell (SS) interactions, middle one has...

The hydrogen bond (HB) basicity of a series ylides containing nitrogen, oxygen, or carbon as heavy atoms, well the influence formation HB complexes on their structure, has been studied. In addition, in this paper we propose some rather strong HBs (that could be considered low-barrier bonds, LBHBs) between and different neutral molecules. chosen for study were H3N+−N-H, Me3N+−N-H, H2O+−N-H, Me2O+−N-H, H2O+−O-, Me2O+−O-, Me3N+−C-H2. As donors, classical donors such HF, HCN, HCCH used. analysis...

The term “hydrogen bond” has been used in the literature for nearly a century now. While its importance realized by physicists, chemists, biologists, and material scientists, there continual debate about what this means. This intensified following some important experimental results, especially last decade, which questioned basis of traditional view on hydrogen bonding. Most among them are direct evidence partial covalent nature observation blue-shift stretching frequency X – H···Y bond...

The complexes formed by a variety of anions with perfluoro derivatives benzene, naphthalene, pyridine, thiophene, and furan have been calculated using DFT (B3LYP/6-31++G**) MP2 (MP2/6-31++G** MP2/6-311++G**) ab initio methods. minimum structures show the anion interacting pi-cloud aromatic compounds. interaction energies obtained range between -8 -19 kcal mol(-1). results at MP2/6-31++G** MP2/6-311++G** levels are similar. However, B3LYP/6-31++G** provide longer distances smaller than do...

In this review, we provide a consistent description of noncovalent interactions, covering most groups the Periodic Table. Different types bonds are discussed using their trivial names. Moreover, new name “Spodium bonds” is proposed for group 12 since interactions involving elements as electron acceptors have not yet been named. Excluding hydrogen bonds, following will be discussed: alkali, alkaline earth, regium, spodium, triel, tetrel, pnictogen, chalcogen, halogen, and aerogen, which...

In this article, we report a comprehensive theoretical study of halogen, chalcogen, and pnicogen bonding interactions using large set pure hybrid functionals some ab initio methods. We have observed that the largely overestimate interaction energies when donor atom is anionic (Cl(-) or Br(-)), especially in halogen complexes. To evaluate reliability different DFT (BP86, BP86-D3, BLYP, BLYP-D3, B3LYP, B97-D, B97-D3, PBE0, HSE06, APFD, M06-2X) (MP2, RI-MP2, HF) methods, compared binding...

Abstract The term spodium (Sp) bond is proposed to refer a net attractive interaction between any element of Group 12 and electron‐rich atoms (Lewis bases or anions). These noncovalent interactions are markedly different from coordination bonds (antibonding Sp–ligand orbital involved). Evidence provided for the existence this by calculations at RI‐MP2/aug‐cc‐pVTZ level theory, atoms‐in‐molecules, natural analyses examining solid‐state structures in Cambridge Structure Database.

At the molecular – supramolecular border lie water clusters. Such clusters, Wi, for i=2 to i=10, have been used discuss some fundamental problems, such as covalent nature of hydrogen bonds, properties bulk water, and their conformations. The picture represents examples W8.

Topological analyses of the theoretically calculated electron densities for a large set 163 hydrogen-bonded complexes show that HX interactions can be classified in families according to X (X=atom or pi orbital). Each family is characterised by intrinsic dependencies between topological and energetic properties density at hydrogen-bond critical point, as well each them bonding distance. Comparing different atom-acceptor families, these are function van der Waals radius r(X) electronegativity...

The nature of bifurcated or three-centered hydrogen bonds (HB) has been investigated. Different families compounds were chosen: monomers with intramolecular HB, dimers a HB donor (HBD) and molecule two acceptor (HBA) groups, trimers one HBD HBAs. All the systems optimized at B3LYP/6-31G* level, and, in case complexes, interaction energies evaluated corrected basis set superposition error (BSSE). electronic these HBs was analyzed by means atoms molecules (AIM) approach. present study...

Theoretical calculations on a series of SiXY3···ZW complexes, where X and Y are H, F, Cl, Z corresponds to an electron donor atom (ZW = NH3, NCH, CNH, OH2, FH), were performed. The carried out using B3LYP/6-311++G**, MP2/6-311++G** MP2/6-311++G(2d,2p) computational methods. density was characterized by means the atoms in molecules (AIM) methodology, interaction nature studied with NBO method. Finally, effect complexation nuclear chemical shieldings evaluated GIAO results display wide range...

The (13)C and (15)N absolute shieldings of 28 compounds have been calculated at the GIAO/B3LYP/6-311 + G** level to complete a collection data already published. This has allowed us devise new equations relating delta sigma for these nuclei based on 461 points ((13)C) 70(72) ((15)N).

A theoretical study of the charge-transfer complexes formed by dihalogen compounds (F2, Cl2, Br2, FBr, FCl, and ClBr) electron donors (FH, OH2, NH3, CO, NCH, C2H2) has been carried out. The geometries, energies, electronic spectroscopic properties these have compared with corresponding hydrogen bonded FH same donors. hybrid HF-DFT, B3LYP, second-order Møllet−Plesset perturbation, MP2, methods used. analyzed include geometry, energy, distribution using atoms in molecules (AIM) methodology,...

Ab initio calculations have been carried out in a systematic investigation of P···N pnicogen complexes H(2)XP:NXH(2) for X ═ H, CH(3), NH(2), OH, F, and Cl, as well selected with different substituents bonded to P N. Binding energies range from 8 27 kJ mol(-1) increase 39 H(2)FP:N(CH(3))H(2). Equilibrium structures nearly linear A-P-N arrangement, A being the atom directly P. correlate intermolecular N-P distances bonding parameters obtained AIM SAPT analyses. Complexation increases (31)P...

A theoretical study of the complexes formed by hypohalous acids (HOX, X = F, Cl, Br, I, and At) with three nitrogenated bases (NH3, N2, NCH) has been carried out means ab initio methods, up to MP2/aug-cc-pVTZ computational method. In general, two minima are found, one an OH···N hydrogen bond other a X···N halogen bond. While first is more stable for smallest derivatives, present similar stabilities iodine case halogen-bonded structure most hypoastatous acid complexes.

The complexes between BeX2 (X = H, F, Cl, OH) with different Lewis bases have been investigated through the use of B3LYP, MP2, and CCSD(T) approaches. This theoretical survey showed that these are stabilized interaction Be atom basic center base, which characterized by electron densities at corresponding bond critical points larger than those found in conventional hydrogen bonds (HBs). Actually, all bonding indices indicate that, although interactions we named "beryllium bonds" general...

An ab initio MP2/aug′-cc-pVTZ study has been carried out on complexes formed between PO2X (X = F and Cl) as the Lewis acids a series of nitrogen bases ZN, including NH3, H2C═NH, NH2F, NP, NCH, NCF, NF3, N2. Binding energies these vary from −10 to −150 kJ/mol, P—N distances 1.88 2.72 Å. Complexes ZN:PO2F have stronger P...N bonds shorter than corresponding ZN:PO2Cl. Charge transfer N lone pair through π-hole P—X P—O σ* orbitals leads stabilization complexes, although charge-transfer can be...

Abstract A theoretical study of the HTeXH (X=O, S, Se and Te) monomers homodimers was carried out by means second‐order Møller‐Plesset perturbation theory (MP2) computational methods. In case monomers, isomerization energy from to H 2 Te=X X=Te Se, rotational transition‐state barriers were obtained. Due chiral nature these compounds, homo heterochiral dimers found. The electron density complexes characterized with atoms‐in‐molecules (AIM) methodology, finding a large variety interactions....

Ab initio MP2/aug′-cc-pVTZ calculations have been carried out to investigate the influence of F–H···F hydrogen bonds on P···P pnicogen bond in complexes nFH:(PH2F)2 for n = 1–3. The formation leads a shortening P–P distance, lengthening P–F distance involved bond, strengthening interaction, and changes atomic populations, NMR 31P chemical shieldings, 1pJ(P–P) coupling constants. magnitude these depends number FH molecules their positions complex are relatively modest except 2FH:(PH2F)2...