Structure, stability and spectral signatures of monoprotic carborane acid–water clusters (CBWn, where n = 1–6)

Abstract

The gas phase structure, stability, spectra, and proton transfer properties of monoprotic carborane acid-water clusters [CB(11)F(m)H(11-m)(OH(2))(1)]-(H(2)O)(n) (where m = 0, 5, and 10; n = 1-6) have been calculated using density functional theory (DFT) with the Becke's three-parameter hybrid exchange functional and Lee-Yang-Parr correlation functional (B3LYP) using 6-31+G* basis set. Results reveal that Eigen cation defects are found in CBW(n) (where n = 2-6) clusters and these clusters are significantly more stable than the non-Eigen geometry. In addition to the conventional hydrogen bond (H-bond) the role of dihydrogen bond (DHB) and halogen bond (XB) in the stabilization of these clusters can be observed from the molecular graphs derived from the atoms in molecules (AIM) analysis. Spectral information shows the features of Eigen cation and proton oscillation involved in the proton transfer process. The dissociation of proton from the perfluoro derivatives with two water molecules is more favorable when compared to the other derivatives.

Twisted Eigen Can Induce Proton Transfer at a Hydrophobic–Hydrophilic Interface

“…It was found from earlier reports that protons in the water chain ( i.e. linear) are more stable than the cyclic PWCs. − , Even though BZH + W 4e is stabilized by cyclic water tetramer conformation, because of the primary shell C–H + ···O interaction, the energies are reduced. When geometry optimization was carried out using MP2/6-311++G**, this isomer is stabilized by O–H + ···π (2.181 Å) interaction (BZH + W 4b (*) ).…”

“…The calculated vibrational stretching frequencies of the BZH + W n (where n = 1–4) clusters at the B3LYP/6-311++G** level of theory are provided in Table along with the available experimental values. − The spectral details of other water clusters ( n = 5–6) are given in Table S2 (Supporting Information). Earlier reports state that the B3LYP method is reliable to predict the harmonic vibrational frequencies of water and PWCs. − Thus, we have chosen the B3LYP method to study the spectral features of the BZH + W n clusters. The calculated and experimental ν OH stretching frequency of the water molecule is 3757 and 3756 cm –1 , respectively .…”

“…n = 1–6) along with the spectral signatures of PWC ( i.e. Eigen and Zundel) isomers using various ab initio and density functional theory (DFT) methods. − These studies reveal that the DFT-B3LYP method is more suitable for the predictions of structure, stability, and infrared (IR) spectral features of the water clusters …”

“…It was found from earlier reports that protons in the water chain (i.e. linear) are more stable than the cyclic PWCs [18][19][20][21]…”

Anisotropic diffusion of water molecules in hydroxyapatite nanopores

“…These substitutions HAP-based materials allowed the investigation of the interactions between HAP surfaces with biomolecules (Almora- Barrios et al 2009;Katti et al 2010;Kandori et al 2000a;Hernandez et al 2015;Lukasheva and Tolmachev 2015), water (Zhao et al 2014), ions (de Leeuw 2004a , b;Sakhno et al 2010 ), and gases (Chi-atti et al 2013). Water plays a crucial role during bone mineralization and in the protein interaction (Corno et al 2010;Qin et al 2012;Nair et al 2014;Lemaire et al 2015a) as they can act as a prominent charge carrier, transporting ions (Prakash et al 2009;Prakash and Subramanian 2011) and maintaining the pH of the medium. When considering cells nanopores of transmembrane proteins (Hille 2001) or bone nanopores (Pham et al 2015), the interactions between water molecules and the polar groups of HAP (calcium (Ca 2+ ), phosphate (PO 3 4 − ), and hydroxyl (OH − ) ions) may affect the local environment of the interface, modifying the diffusion of water mole-cules, which tend to be reduced when compared with the bulk (Bhide and Berkowitz 2005;von Hansen et al 2013;Lemaire et al 2015b).…”