Highs and Lows of Bond Lengths: Is There Any Limit?

Abstract

Tw od istinct points on the potential energy curve (PEC) of apairwise interaction, the zero-energy crossing point and the point where the stretching force constant vanishes, allowu st oa nticipate the range of possible distances between two atoms in diatomic,m olecular moieties and crystalline systems.W es howt hat these bond-stability boundaries are unambiguously defined and correlate with topological descriptors of electron-density-based scalar fields,a nd can be calculated using generic PECs.C hemical databases and quantum-mechanical calculations are used to analyzeafull set of diatomic bonds of atoms from the s-p main block. Emphasis is placed on the effect of substituents in C À C covalent bonds,c oncluding that distances shorter than 1.14 or longer than 2.0 are unlikely to be achieved, in agreement with ultra-high-pressure data and transition-state distances, respectively.Presumed exceptions are used to place our model in the correct framework and to formulate ac onjecture for chained interactions,w hicho ffers an explanation for the multimodal histogram of O À Hdistances reported for hundreds of chemical systems.

N/O→B dative bonds supplemented by N–HN/HC hydrogen bonds make BN-cages an attractive candidate for DNA-nucleobase adsorption – an MP2 prediction

“…In this structure, the N–H bond distance of 1.688 Å is shortest compared with other such N–HN bonds in guanine and adenine complexes. The B–O bond is stronger 71,72 than the BN bond in the diatomic molecular system and the B–O bond (1.525 Å) is shorter than the B–N bond (1.625 Å). Although the B–O dative bond distance of 1.528 Å in G3 is closer to the diatomic molecular distance, the G3 structure is less stable by about 6.0 kcal mol −1 than other B 12 N 12 -guanine complexes.…”

Spectroscopically Visualizing the Evolution of Hydrogen-Bonding Interactions

“…Thus, the proton-donating abilities of these typical proton donors were determined to be in the following order: HPW (δ 13 C = 235, 246 ppm) > H-Beta (δ 13 C = 224 ppm) > H-ZSM-5 (δ 13 C = 223 ppm) > H-MOR (δ 13 C = 221 ppm) > H-SSZ-13 (δ 13 C = 220 ppm) > H-SAPO-34 (δ 13 C = 218 ppm). However, the dependence of the 13 C signal of 2-13 C-acetone and the corresponding 1 H resonance of the Hbonding proton in a specific interaction configuration is still unclear. For example, it is unknown how to correlate the two 13 C signals (i.e., 235 and 246 ppm) and two 1 H resonances (i.e., 15.9 and 21.8 ppm) in the 2-13 C-acetone-loaded HPW.…”

“…As a magical and unique interaction in nature, the ubiquitous hydrogen bond (H-bond) is of great importance and is extensively involved in various chemical, biochemical, and material systems. − For example, the complex H-bond network in water governs its miraculous physicochemical properties. − The double helical structures of DNA are closely related to H-bonds . Furthermore, the adsorption, activation, and conversion of various reactant molecules and the sequential formation of diverse intermediates and products during many important Brønsted acid-catalyzed reactions are accompanied by the dynamic variation of H-bonds as well. − Numerous experimental and theoretical techniques have been devoted to the investigation of the origins, definitions, and types of H-bonds; − however, obtaining a precise molecular description of the detailed characteristics of H-bonds is still a rather challenging task. Recently, Tokmakoff et al carried out highly groundbreaking experiments to distinguish H-bonds and covalent bonds .…”

Crystal structure and Hirshfeld surface analysis of poly[[tetraaqua(μ-1,3,4,7,8,10,12,13,16,17,19,22-dodecaazatetracyclo[8.8.4.13,17.18,12]tetracosane-5,6,14,15,20,21-hexaonato)iron(IV)dilithium] tetrahydrate]

“…In addition, the crystal structure is consolidated by an extensive system of hydrogen bonds (Table 2). Based on the results of recent studies (Lobato et al, 2021), the distance of 2.14 A ˚was used as a criterion for the demarcation of O-H� � �O hydrogen bonds and O� � �H van der Waals interactions. According to this criterion, 14 O� � �H contacts were identified as hydrogen bonds.…”