Microwave spectroscopic and computational analyses of the phenylacetylene⋯methanol complex: insights into intermolecular interactions.

The microwave spectra of five isotopologues of phenylacetylene⋯methanol complex, CHCCH⋯CHOH, CHCCH⋯CHOD, CHCCH⋯CDOD, CHCCD⋯CHOH and CHCCH⋯CHOH, have been observed through Fourier transform microwave spectroscopy. Rotational spectra unambiguously unveil a specific structural arrangement characterised by dual interactions between the phenylacetylene and methanol. CHOH serves as a hydrogen bond donor to the acetylenic π-cloud while concurrently accepting a hydrogen bond from the C-H group of the PhAc moiety.

Unified classification of non-covalent bonds formed by main group elements: a bridge to chemical bonding.

Using correlation plots of binding energy and electron density at the bond critical point, we investigated the nature of intermolecular non-covalent bonds (D-X⋯A, where D = O/S/F/Cl/Br/H, mostly, X = main group elements (except noble gases), A = HO, NH, HS, PH, HCHO, CH, HCN, CO, CHOH, and CHOCH). The binding energies were calculated at the MP2 level of theory, followed by Atoms in Molecules (AIM) analysis of the wave functions to obtain the electron density at the bond critical point (BCP). For each non-covalent bond, the slopes of the binding energy electron density plot have been determined.

Recent advances in design and characterization of superalkali-based materials and their potential applications: A review.

In the advancement of novel materials, chemistry plays a vital role in developing the realm where we survive. Superalkalis are a group of clusters/molecules having lower ionization potentials (IPs) than that of the cesium atom (3.89 eV) and thus, show excellent reducing properties.

Non-covalent bonds in group 1 and group 2 elements: the 'alkalene bond'.

The non-covalent bonds formed by group 1 and group 2 elements were systematically analysed by calculations at the MP2/aug-cc-pVDZ (for Ca, 6-311++G(2df,p) basis sets were used) level of theory to classify the weak bonds, followed by Atoms in Molecules (AIM) analysis of the wave functions. It has been established that there is a strong correlation between the electron density at the non-covalent bond critical point (BCP) and the binding energy for each homogeneous sample of complexes. The slopes of the electron density binding energy plot have been obtained for group 1 and group 2 donor molecules (D-X⋯A, for X = H, D = F/-OH/-SH, for X = Li, Na, D = F/Cl/Br and for X = Be, Mg, and Ca, D = F/Cl/H) with a set of acceptor molecules (A), which includes HO, NH, HS, PH, HCHO, CH, HCN, CO, CHOH and CHOCH.

Structure and Internal Motions of a Multifunctional Alcohol-Water Complex: Rotational Spectroscopy of the Propargyl Alcohol···HO Dimer.

We have studied the rotational spectra of the propargyl alcohol (PA)-water complex using a pulsed-nozzle Fourier transform microwave spectrometer. A hydrogen-bonded ring structure is observed. The propargyl alcohol acts as an H-bond donor to form a strong O-H···O bond with HO, and HO donates back an H-bond to the acetylenic moiety, forming a weak O-H···π bond.

A review on hydroxyapatite coatings for the biomedical applications: experimental and theoretical perspectives.

The production of hydroxyapatite (HAP) composite coatings has continuously been investigated for bone tissue applications during the last few decades due to their significant bioactivity and osteoconductivity. Herein, we highlight the recent experimental and theoretical progresses on HAP coatings, which may bridge the existing gap between theory and practice. The experimental studies mainly deal with electrochemical (EC) and electrophoretic (EP) deposition for the synthesis of nano-HAP in the form of coatings.

Isolation of a Halogen-Bonded Complex Formed between Methane and Chlorine Monofluoride and Characterisation by Rotational Spectroscopy and Ab Initio Calculations.

A halogen-bonded complex formed between methane and chlorine monofluoride has been isolated in the gas phase before the reaction between the components and has been characterised through its rotational spectrum, which is of the symmetric-top type but only exhibits = 0 type transitions at the low effective temperature of the pulsed-jet experiment. Spectroscopic constants for two low-lying states that result from internal rotation of the CH subunit were detected for each of the two isotopic varieties HC···ClF and HC···ClF and were analysed to show that ClF lies on the symmetry axis with Cl located closer than F to the C atom, at the distance (C···Cl) ≅ 3.28 Å and with an intermolecular stretching force constant ≅ 4 N m.

Inter/Intramolecular Bonds in TH (T = C/Si/Ge): H as Tetrel Bond Acceptor and the Uniqueness of Carbon Bonds.

Atoms in molecules (AIM), natural bond orbital (NBO), and normal coordinate analysis have been carried out at the global minimum structures of TH (T = C/Si/Ge). All these analyses lead to a consistent structure for these three protonated TH molecules. The CH has a structure with three short and two long C-H covalent bonds and no H-H bond.

The H S Dimer is Hydrogen-Bonded: Direct Confirmation from Microwave Spectroscopy.

Ice and solid H S look as different as pears and oranges, leading Pauling to conclude that H O has hydrogen bonds and H S has van der Waals interactions. Now it is shown that the H S dimer, like the H O dimer, is indeed hydrogen-bonded.

H2O-CH4 and H2S-CH4 complexes: a direct comparison through molecular beam experiments and ab initio calculations.

New molecular beam scattering experiments have been performed to measure the total (elastic plus inelastic) cross sections as a function of the velocity in collisions between water and hydrogen sulfide projectile molecules and the methane target. Measured data have been exploited to characterize the range and strength of the intermolecular interaction in such systems, which are of relevance as they drive the gas phase molecular dynamics and the clathrate formation. Complementary information has been obtained by rotational spectra, recorded for the hydrogen sulfide-methane complex, with a pulsed nozzle Fourier transform microwave spectrometer.

Microwave spectroscopic and theoretical investigations of the strongly hydrogen bonded hexafluoroisopropanol···water complex.

This paper reports microwave spectroscopic and theoretical investigations on the interaction of water with hexafluoroisopropanol (HFIP). The HFIP monomer can exist in two conformations, antiperiplanar (AP) and synclinical (SC). The former is about 5 kJ mol(-1) more stable than the latter.

Microwave Spectrum of Hexafluoroisopropanol and Torsional Behavior of Molecules with a CF3-C-CF3 Group.

This paper presents the first microwave spectroscopic investigation on hexafluoroisopropanol (HFIP). A pulsed nozzle Fourier transform microwave spectrometer has been used to determine the rotational constants for HFIP as A = 2105.12166(18) MHz, B = 1053.

Conformational stability and intramolecular hydrogen bonding in 1,2-ethanediol and 1,4-butanediol.

The gas-phase infrared spectra of 1,2-ED and 1,4-BD have been recorded at three different temperatures using a multipass gas cell of 6 m optical path length. DFT calculation has also been carried out using 6-311++G** and aug-cc-pVDZ basis sets to look for the existence of intramolecular hydrogen bonding in them from the red shift and infrared absorption intensity enhancement of the bonded O-H band compared to that of the free O-H band. Equilibrium population analysis with 10 conformers of 1,2-ED and 1,4-BD at experimental temperatures were carried out for the reconstruction of the observed vibrational spectra at that temperature using standard statistical relationships.

Three centered hydrogen bonds of the type C=O···H(N)···X-C in diphenyloxamide derivatives involving halogens and a rotating CF3 group: NMR, QTAIM, NCI and NBO studies.

The existence of three centered C=O···H(N)···X-C hydrogen bonds (H-bonds) involving organic fluorine and other halogens in diphenyloxamide derivatives has been explored by NMR spectroscopy and quantum theoretical studies. The three centered H-bond with the participation of a rotating CF3 group and the F···H-N intramolecular hydrogen bonds, a rare observation of its kind in organofluorine compounds, has been detected. It is also unambiguously established by a number of one and two dimensional NMR experiments, such as temperature perturbation, solvent titration, (15)N-(1)H HSQC, and (19)F-(1)H HOESY, and is also confirmed by theoretical calculations, such as quantum theory of atoms in molecules (QTAIM), natural bond orbital (NBO) and non-covalent interaction (NCI).

Dynamics of the chemical bond: inter- and intra-molecular hydrogen bond.

In this discussion, we show that a static definition of a 'bond' is not viable by looking at a few examples for both inter- and intra-molecular hydrogen bonding. This follows from our earlier work (Goswami and Arunan, Phys. Chem.

Rotational spectra of propargyl alcohol dimer: a dimer bound with three different types of hydrogen bonds.

Pure rotational spectra of the propargyl alcohol dimer and its three deuterium isotopologues have been observed in the 4 to 13 GHz range using a pulsed-nozzle Fourier transform microwave spectrometer. For the parent dimer, a total of 51 transitions could be observed and fitted within experimental uncertainty. For two mono-substituted and one bi-substituted deuterium isotopologues, a total of 14, 17, and 19 transitions were observed, respectively.

The X-C···π (X = F, Cl, Br, CN) carbon bond.

High-level ab initio calculations have been used to study the interactions between the CH3 group of CH3X (X = F, Cl, Br, CN) molecules and π-electrons. These interactions are important because of the abundance of both the CH3 groups and π-electrons in biological systems. Complexes between C2H4/C2H2 and CH3X molecules have been used as model systems.

Hydrogen bonding, halogen bonding and lithium bonding: an atoms in molecules and natural bond orbital perspective towards conservation of total bond order, inter- and intra-molecular bonding.

One hundred complexes have been investigated exhibiting D-X···A interactions, where X = H, Cl or Li and DX is the 'X bond' donor and A is the acceptor. The optimized structures of all these complexes have been used to propose a generalized 'Legon-Millen rule' for the angular geometry in all these interactions. A detailed Atoms in Molecules (AIM) theoretical analysis confirms an important conclusion, known in the literature: there is a strong correlation between the electron density at the XA bond critical point (BCP) and the interaction energy for all these interactions.

Thermal decomposition of propargyl alcohol: single pulse shock tube experimental and ab initio theoretical study.

Thermal decomposition of propargyl alcohol (C3H3OH), a molecule of interest in interstellar chemistry and combustion, was investigated using a single pulse shock tube in the temperature ranging from 953 to 1262 K. The products identified include acetylene, propyne, vinylacetylene, propynal, propenal, and benzene. The experimentally observed overall rate constant for thermal decomposition of propargyl alcohol was found to be k = 10((10.

Microwave, infrared-microwave double resonance, and theoretical studies of C2H4···H2S complex.

In this manuscript, rotational spectra of four new isotopologues of the S-H···π bonded C2H4···H2S complex, i.e., C2D4···H2S, C2D4···D2S, C2D4···HDS, and (13)CCH4···H2S have been reported and analyzed.