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Abinitio MP2/aug-cc-pvDZ and density functional B3LYP calculationswith the 6-311(d,p) basis set are performed to investigate theconformation of desflurane (CHF2OCHFCF3), itsacidity/basicity and its interaction with one water molecule. Thecalculations include the optimized geometries, the harmonic frequenciesof relevant vibrational modes, the binding energies with water, anda detailed natural bond orbital (NBO) analysis Iincluding the NBOcharges, the hybridization of the C atoms and the intra- and intermolecularhyperconjugations. The relative energies of the two most stable conformersare discussed as a function of the total hyperconjugative energiesresulting from the interaction of lone pairs of the O and F atomsto the different antibonding orbitals of desflurane. The proton affinityis the same for both conformers but the acidity of the CH bond islarger for the less stable conformer. The binding energies of thecomplexes of two desflurane conformers with one water molecule rangefrom −2.75 to −3.23 kcal mol–1. Dependingon the structure of the complexes, the CH bonds involved in the interactionare contracted or elongated. The σ*(CH) occupation predominatesover the hybridization effect in determining the CH bond length. Thereis an unexpected charge transfer to the external OH bond of the watermolecule. This effect is in good agreement with theoretical data onthe complexes between fluorinated dimethyl ethers and water and seemsto depend on the number of F atoms implanted on the ethermolecule. [ABSTRACT FROM AUTHOR]

In this work, one new centrosymmetric trinuclear Zn(II) complex 1 , [{(OCN)Zn(L)} 2 Zn], using a salen-type ligand (H 2 L) in the presence of OCN - was synthesized and characterized via elemental, spectral, SEM-EDX, and single-crystal X-ray diffraction (SCXRD) study. In 1 , SCXRD reveals two different stereochemical environments of zinc metal ions; one terminal Zn(II) center adopts square pyramidal geometries with the Addison parameter (τ) 0.095, and the central Zn(II) is tetracoordinated tetrahedral geometry. This article provides evidence of the significance and presence of spodium bonds (SpBs) in solid-state crystal structures involving a pseudotetrahedral environment of the central Zn-atom. X-ray structures reveal intramolecular Zn···O SpBs caused by the methoxy (-OCH 3 ) substituent O-atom adjacent to the coordinated phenoxy O-atom. These noncovalent interactions have been thoroughly studied using density functional theory calculations at the RI-BP86[2]-D3[3]/def2-TZVP level of theory that characterizes the nature of SpBs, including the Baders quantum theory of atoms-in-molecules "QTAIM", molecular electrostatic potential (MEP) surface, and noncovalent index plot (NCI). In addition, a unique complex-isomer-based theoretical model has been vividly employed to estimate the SpBs energy in the complex. Natural bond orbital (NBO) analysis also tries to establish the differentiation between σ-hole and π-hole SpBs' natures more authentically. The complex energy frameworks were used to investigate noncovalent interactions. To better understand the different intermolecular interactions, we conducted a Hirshfeld surface, which revealed N···H (15.4%) and O···H (9.1%) contacts and Zn···O (5.1%) (SpBs)., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

Ab initio MP2/aug-cc-pVTZ calculations have been carried out in order to study the nature of P···Cl halogen bonding interaction between a phosphorus atom in an aromatic ring in para-substituted phosphabenzene (PPBZ) and ClF molecule. The interaction of PPBZ with ClF results in two different types of complexes: (i) complex formation through the chlorine-shared halogen bond (T1-X-PPBZ·ClF) and (ii) complex formation via halogen-π interaction (T2-X-PPBZ·ClF). T1-X-PPBZ·ClF complexes are found to be more stable than the T2-X-PPBZ·ClF complexes. This work also presents a general criterion to distinguish a chlorine-shared halogen bond from a traditional halogen bond and sheds light on the formation of the chlorine-shared halogen bond. The binding energy of T1-X-PPBZ·ClF complexes correlates well with the negative electrostatic potential of the P atom and PA value of the substituted PPBZ. The properties of both T1-X-PPBZ·ClF and T2-X-PPBZ·ClF complexes are analyzed using atom-in-molecule, natural bond orbital, and symmetry-adapted perturbation theory calculations. The variation of the Cl-F bond distances and the redshifts of the ν(ClF) vibration resulting from the interaction with PPBZs are discussed., Competing Interests: The authors declare no competing financial interest., (Copyright © 2020 American Chemical Society.)

Theoretical investigations are carried out on the interaction between fluorinated dimethyl ethers (FDME, nF = 0-4) and the Cl atom. Short intermolecular O···Cl distances between 2.401 and 2.938 Å reveal the formation of a new class of complexes. The interaction energies calculated with the G2(MP2) method range between -9.1 (nF = 4) and -26.0 (nF = 0) kJ/mol. The charge transfer occurring from the ethers to atomic Cl is moderate and ranges between 0.012 e (nF = 4) to 0.188 e (nF = 0). The binding energies are linearly related to the proton affinity, to the charge transfer (CT) occurring in the molecular system and inversely proportional to the ionization potential and electron affinity (IP-EA) values. The CT and spin density data indicate substantial two-center-three-electron O···Cl interaction in CH3OCH3···Cl and CH3OCH2F···Cl systems, whereas for highly fluorinated ethers the interaction is predominantly electrostatic in nature. The formation of the complex results in a contraction of the CH bonds, especially in the gauche position. The blue shifts of the C-H stretching vibrations calculated in the partially deuterated isotopomers range between 2 and 54 cm(-1) and are correlated to the variation of the CH distances.