Interesting fluorine anion water clusters [F−·(H2O)n] in metal complex crystals

CrystEngComm ◽  
2018 ◽  
Vol 20 (27) ◽  
pp. 3849-3857 ◽  
Author(s):  
Fang Fang Jian ◽  
E. Liu ◽  
Jun Ying Ma

Three crystalline complexes containing fluorine anion water cluster were reported. The fluoride anions and water molecules are H-bonded to each other in an alternating fashion within the fluoride–water hybrid cluster, where a fluoride anion plays the important role.

2019 ◽  
Vol 91 (2) ◽  
pp. 301-316 ◽  
Author(s):  
Misako Aida ◽  
Dai Akase

Abstract Hydrogen-bond (HB) patterns correspond to topologically distinct isomers of water clusters, and can be expressed by digraphs. The HB pattern is used to divide the configuration space of water cluster at a finite temperature. The populations of the HB patterns are transformed into the relative Helmholtz energies. The method is based on the combination of molecular simulation with graph theory. At a finite temperature it can be observed that other isomers than local minimum structures on the potential energy surface are highly populated. The dipole moment of a constituent molecule in a water cluster is enhanced depending on the local HB network around the water molecule. Rooted digraph is used to represent topologically distinct isomers of protonated water (PW) clusters. O–H bonds of PW clusters are classified into 10 topological types based on the combination of the local HB types of the contributing water molecules to the O–H bond. If the topological type is the same, vibrational frequencies of those O–H bonds of PW clusters are similar even in different isomers; i.e. vibrational frequency of O–H bond is transferable, and can be used as a vibrational spectral signature of PW clusters.


2019 ◽  
Vol 116 (45) ◽  
pp. 22540-22544 ◽  
Author(s):  
Linda Feketeová ◽  
Paul Bertier ◽  
Thibaud Salbaing ◽  
Toshiyuki Azuma ◽  
Florent Calvo ◽  
...  

Atmospheric aerosols are one of the major factors affecting planetary climate, and the addition of anthropogenic molecules into the atmosphere is known to strongly affect cloud formation. The broad variety of compounds present in such dilute media and their specific underlying thermalization processes at the nanoscale make a complete quantitative description of atmospheric aerosol formation certainly challenging. In particular, it requires fundamental knowledge about the role of impurities in water cluster growth, a crucial step in the early stage of aerosol and cloud formation. Here, we show how a hydrophobic pyridinium ion within a water cluster drastically changes the thermalization properties, which will in turn change the corresponding propensity for water cluster growth. The combination of velocity map imaging with a recently developed mass spectrometry technique allows the direct measurement of the velocity distribution of the water molecules evaporated from excited clusters. In contrast to previous results on pure water clusters, the low-velocity part of the distributions for pyridinium-doped water clusters is composed of 2 distinct Maxwell–Boltzmann distributions, indicating out-of-equilibrium evaporation. More generally, the evaporation of water molecules from excited clusters is found to be much slower when the cluster is doped with a pyridinium ion. Therefore, the presence of a contaminant molecule in the nascent cluster changes the energy storage and disposal in the early stages of gas-to-particle conversion, thereby leading to an increased rate of formation of water clusters and consequently facilitating homogeneous nucleation at the early stages of atmospheric aerosol formation.


Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2787
Author(s):  
Kajetan Dąbrowa ◽  
Magdalena Ceborska ◽  
Janusz Jurczak

In this paper, we present a comparative analysis of the solid state structures of three well-resolved hydrates of macrocyclic host molecules 1a, 1b, and 2 containing an intrannular amide-aryl substituent (lariat arm) connected to a fixed 26-membered ring in a normal (-NHCOAr, hosts 1a and 1b) or reverse manner (-CONHAr, host 2). Despite different chemical structures, these hosts crystallize as isostructural tetrahydrates in the same P-1 space group. Moreover, their crystals exhibit identical hydrogen bond motifs resulting in a stabilization of an almost identical unusual octameric water cluster built from the cyclic tetramer core and four water molecules, attached sequentially in an “up-and-down” manner. Further analysis reveals that, among the series, the structure of host 2 provides the most suitable environment for the accommodation of this type of water cluster.


2021 ◽  
Author(s):  
Igor Shevchenko

Abstract The variations of solar activity and distribution of solar energy due to the rotation of the Earth around its axis and around the Sun exert a strong influence on the self-organization of water molecules. As a result, the rate of hydrolytic processes with the participation of water clusters displays diurnal, very large annual variations, and is also modulated by the 11-year cycles of solar activity. It also depends on the geographic latitude and can be different at the same time in the Northern and Southern Hemispheres. This phenomenon is well accounted for by the influence of muons on the self-organization of water molecules. Muons are constantly generated in the upper atmosphere by the solar wind. They reach the surface of the Earth and can penetrate to some depth underground. Buildings also absorb muons. For this reason, the rate of hydrolysis outside and inside buildings, as well as underground, can differ significantly from each other.


2019 ◽  
Vol 31 (8) ◽  
pp. 1755-1761
Author(s):  
K. Naresh ◽  
B.N. Sivasankar

A new copper complex of pyridine-2,6-dicarboxylate containing hydrazinium cation, formulated as (N2H5)2[Cu(PDC)2]·4H2O (PDC = pyridine-2,6-dicarboxylate) has been synthesized from copper(II) nitrate, hydrazine hydrate and pyridine-2,6-dicarboxylic acid as a single crystal and characterized by elemental analysis and spectroscopic (IR and UV-visible), thermal (TG/DTG), single crystal X-ray diffraction and biological studies. A six-coordinate complex with a distorted octahedral geometry around Cu(II) ion is proposed and confirmed by X-ray single crystal method. The structure reveals that two pyridine-2,6-dicarboxylate species acting as tridentate ligands and hydrazinium cation present as a counter ion along with non-coordinated four water molecules. The structural units of copper(II) is mutually held by the hydrogen bonds and π···π and C–O···π interactions. The copper(II) complex is connected to one another via O–H···O hydrogen bonds, forming water clusters, which plays an important role in the stabilization of the crystal structure. In the water clusters, the water molecules are trapped by the cooperative association of coordination interactions as well as hydrogen bonds. Both cation and anion interactions and crystal from various types of intermolecular contacts and their importance were explored using Hirshfeld surface analysis. This indicates that O···H/H···O interactions are the superior interactions conforming excessive H-bond in the molecular structure. The interaction of copper(II) complex with calf thymus DNA (CT-DNA) was investigated by electronic absorption spectroscopic technique. The electronic evidence strongly shows that the compound interacts with calf thymus through intercalation with a binding constant of Kb = 5.7 × 104 M–1.


2019 ◽  
Vol 15 ◽  
pp. 1592-1600 ◽  
Author(s):  
Stiliyana Pereva ◽  
Valya Nikolova ◽  
Silvia Angelova ◽  
Tony Spassov ◽  
Todor Dudev

Cyclodextrins (CDs) are native host systems with inherent ability to form inclusion complexes with various molecular entities, mostly hydrophobic substances. Host cyclodextrins are accommodative to water molecules as well and contain water in the native state. For β-cyclodextrin (β-CD), there is no consensus regarding the number of bound water molecules and the location of their coordination. A number of intriguing questions remain: (1) Which localities of the host’s macrocycle are the strongest attractors for the guest water molecules? (2) What are the stabilizing factors for the water clusters in the interior of β-CD and what type of interactions between water molecules and cavity walls or between the water molecules themselves are dominating the energetics of the β-CD hydration? (3) What is the maximum number of water molecules inside the cavity of β-CD? (4) How do the thermodynamic characteristics of β-CD hydration compare with those of its smaller α-cyclodextrin (α-CD) counterpart? In this study, we address these questions by employing a combination of experimental (DSC/TG) and theoretical (DFT) approaches.


2014 ◽  
Vol 70 (2) ◽  
pp. 198-201 ◽  
Author(s):  
Ji Qi ◽  
Xiang-Sheng Zhai ◽  
Hong-Lin Zhu ◽  
Jian-Li Lin

A tetranuclear CoIIIoxide complex with cubane topology, tetrakis(2,2′-bipyridine-κ2N,N′)di-μ2-carbonato-κ4O:O′-tetra-μ3-oxido-tetracobalt(III) pentadecahydrate, [Co4(CO3)2O4(C10H8N2)4]·15H2O, with an unbounded hydrogen-bonded water layer, has been synthesized by reaction of CoCO3and 2,2′-bipyridine. The solvent water molecules form a hydrogen-bonded net with tetrameric and pentameric water clusters as subunits. The Co4O4cubane-like cores are sandwiched between the water layers, which are further stacked into a three-dimensional metallo-supramolecular network.


2020 ◽  
Vol 20 (8) ◽  
pp. 4799-4806
Author(s):  
Peng Xie ◽  
Shubin Jin ◽  
Chenggang Sun ◽  
Yushu Xie

We performed MD simulations to examine dimethyl sulfoxide (DMSO) nanocluster structures in NaCl aqueous solution with different concentrations (0.45 g/100 mL, 0.9 g/100 mL, 1.8 g/100 mL, 2.7 g/100 mL, and 3.6 g/100 mL). Results showed that interaction between Na+ and DMSO at the first solvation shells was weakened due to acceleration rotational influence of ion driven by NaCl concentration. We investigated the tetrahedral order parameter and average H-B number of water molecules. These results indicated that NaCl influenced the solvation structure of water cluster, but that of DMSO was not affected by NaCl. We also found that Na+ was prior solvated by water solution in these mixture systems, and Cl− only existed in the water cluster in our simulation systems. Consequently, we herein proposed a decentralized model that depicts microphysical structure images of DMSO in NaCl aqueous solution systems.


2007 ◽  
Vol 06 (03) ◽  
pp. 595-609 ◽  
Author(s):  
CLARA JIAYUN MEN ◽  
FU-MING TAO

The structure, stability, and properties of the hydrated clusters of calcium hydroxide, Ca ( OH )2( H 2 O )n, n = 1–6, were investigated using density functional and ab initio quantum chemical methods. The results show that six water molecules are needed to result in the complete dissociation of Ca ( OH )2. The stable and ionic conformer of Ca ( OH )2( H 2 O )6 has C 3 symmetry. Its surprising stability and high IR activity render hydrated clusters of Ca ( OH )2 potentially significant in the nucleation of noctilucent clouds in the mesosphere. Trends in the interaction energies (ΔEe) of the complexes show that water molecules in the first shell of Ca 2+ are highly stable, further alluding to the role of hydrated Ca ( OH )2 in aerosol formation.


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