Infrared studies of water in crystalline hydrates: K2HgCl4.H2O

Infrared spectra of polycrystalline K2HgCl4.H2O at different degrees of deuteration were recorded, in the 4000–250 cm−1 region, at temperatures between liquid-nitrogen and 130 °C. The spectra confirm the existence of a single type of water molecule, engaged in two equivalent hydrogen bonds. The value of 2548 cm−1 for the isolated O—D stretching frequency leads to an estimate of 3.25(3) Å for the O … Cl hydrogen-bond distance, in excellent agreement with the results of X-ray and neutron diffraction. Dynamic coupling is appreciable for stretch, bend, and librational fundamentals but is weaker than in CuCl2.2H2O or K2CuCl4.2H2O, in which the water molecules in the crystal are more tightly bonded.A number of corrected values are reported of isolated O—D stretching frequencies in hydrates studied previously.

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Infrared Studies of Water in Crystalline Hydrates: LiI.3H2O

Canadian Journal of Chemistry ◽

10.1139/v71-058 ◽

1971 ◽

Vol 49 (3) ◽

pp. 347-351 ◽

Cited By ~ 19

Author(s):

George Brink ◽

Michael Falk

Keyword(s):

Hydrogen Bond ◽

Water Molecule ◽

Water Molecules ◽

X Ray Diffraction ◽

Space Group ◽

X Ray ◽

Infrared Studies ◽

Librational Motion ◽

Increasing Temperature ◽

Crystalline Hydrates

The infrared spectra of undeuterated and partially deuterated LiI.3H2O were recorded between 4000 and 1000 cm−1. The splitting of the fundamentals of isotopically dilute HDO indicates that the water molecules are distorted and form one strong, linear OH … I− hydrogen bond and one weak, non-linear hydrogen bond. The non-equivalence of the two hydrogens of the water molecule disagrees with the space group P63mc − C6υ4 for this hydrate, proposed on the basis of X-ray diffraction studies. It is concluded that the space group, including hydrogens, is one of lower symmetry, P63 − C66. The gradual broadening and convergence of the HDO fundamentals at increasing temperature is explained by increasing librational motion of the water molecules.

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Infrared studies of water in crystalline hydrates: NaClO4•H2O, LiClO4•3H2O, and Ba(ClO4)2•3H2O

Canadian Journal of Chemistry ◽

10.1139/v70-347 ◽

1970 ◽

Vol 48 (13) ◽

pp. 2096-2103 ◽

Cited By ~ 50

Author(s):

George Brink ◽

Michael Falk

Keyword(s):

Hydrogen Bond ◽

Hydrogen Atom ◽

Room Temperature ◽

Water Molecules ◽

Weak Hydrogen Bond ◽

Kcal Mole ◽

Hydrogen Bond Energy ◽

Weak Hydrogen Bonds ◽

Infrared Studies ◽

Crystalline Hydrates

Infrared spectra of undeuterated and partially deuterated NaclO4•H2O, LiClO4•3H2O, and Ba(ClO4)2•3H2O were examined. Crystallographic data point to a weak hydrogen bond between water molecules and the perchlorate ions in LiClO•3H2O. This is confirmed by the high HDO stretching frequencies for this compound. The nearly identical HDO stretching frequencies in LiClO4•3H2O, NaClO4•H2O, Ba(ClO4)2•3H2O, and in aqueous solutions of these salts show that similar weak hydrogen bonds occur in all three hydrates and in solution. The hydrogen bond energy is of the order of 2 kcal/mole. In all three compounds the water molecules are symmetric at room temperature. At −165° the water molecules become highly distorted in the sodium compound, slightly distorted in the barium compound, and remain undistorted in the lithium compound. Very narrow OD stretching bands are observed, showing that the hydrogen atom positions are ordered in all three hydrates.

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Neutron crystal structure of human FPPS complexed with risedronate

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273314087798 ◽

2014 ◽

Vol 70 (a1) ◽

pp. C1220-C1220

Author(s):

Takeshi Yokoyama ◽

Andreas Ostermann ◽

Mineyuki Mizuguchi ◽

Nobuo Niimura ◽

Tobias Schrader ◽

...

Keyword(s):

Hydrogen Bond ◽

Neutron Diffraction ◽

Antitumor Agents ◽

Structural Characteristics ◽

Water Soluble ◽

Water Molecules ◽

Protonation State ◽

Hydrogen Atoms ◽

X Ray ◽

Hydrogen Bond Networks

Nitrogen-containing bisphosphonates (N-BPs), such as risedronate and zoledronate, are currently used as clinical drug for bone-resorption diseases and are potent inhibitor of farnesyl pyrophosphate synthase (FPPS). The potential of N-BPs as antitumor agents has also been suggested by the several in vitro and in vivo preclinical studies. However, BP drugs limit their therapeutic use to bone-related diseases, because BPs are highly charged and water soluble molecules. X-ray crystallographic analyses of FPPS with N-BPs have revealed that N-BPs bind to FPPS with three magnesium ions and several water molecules. In order to develop a novel FPPS inhibitor, the hydrogen-bond networks formed by FPPS, BPs and water molecules are necessary to be elucidated. To understand the structural characteristics of N-BPs bound to FPPS, including hydrogen atoms and hydration by water, neutron diffraction studies were initiated using BIODIFF at the Heinz Maier-Leibnitz Zentrum (MLZ). FPPS-risedronate complex crystals of approximate dimensions 2.8 × 2.5 × 1.5 mm (~ 3.5 mm3) were obtained by repeated macro-seeding. Monochromatic neutron diffraction data were collected to 2.4 Å resolution with 98.4% overall completeness and 10.7% Rmerge. As a result of X-ray/neutron joint refinment, R and Rfree values for the neutron data were 19.6 and 23.3%, respectively. This neutron structure clearly reveals the protonation state of risedronate, hydration in the inhibitor-binding region. Furthermore, the amide H/D exchange analysis showed that there is a highly rigid region which regulate the structural change upon the binding of the ligands. Here we will discuss the detailed hydrogen-bond network and the protonation state of FPPS and risedronate.

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Infrared Studies of Water in Crystalline Hydrates: Location of Hydrogen Atoms and Evidence for a Bifurcated Hydrogen Bond in K2SnCl4•H2O

Canadian Journal of Chemistry ◽

10.1139/v74-345 ◽

1974 ◽

Vol 52 (13) ◽

pp. 2380-2388 ◽

Cited By ~ 42

Author(s):

Michael Falk ◽

Chung-Hsi Huang ◽

Osvald Knop

Keyword(s):

Hydrogen Bonding ◽

Spectral Characteristics ◽

Supplementary Information ◽

Water Molecules ◽

Dynamic Coupling ◽

Hydrogen Atoms ◽

Infrared Studies ◽

Infrared Spectral ◽

Bifurcated Hydrogen Bond ◽

Crystalline Hydrates

Infrared spectra of polycrystalline K2SnCl4•H2O at different degrees of deuteration were recorded between 4000 and 300 cm−1 at temperatures between 30 and −160 °C. The spectra are consistent with the crystal structure proposed by Kamenar and Grdenić. The water molecules are all equivalent and asymmetric. They are sufficiently well separated from one another for the dynamic coupling of vibrations to be negligible. Both hydrogens of the water molecule participate in hydrogen bonding; one of the hydrogen bonds is weak and bifurcated. Positional parameters of the hydrogen atoms have been calculated using supplementary information from available n.m.r. studies. Infrared spectral characteristics of water molecules engaged in bifurcated hydrogen bonding are discussed.

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Synthesis and Complexation Properties of 2-Hydroxy-5-methoxyphenylphosphonic Acid (H3L1). Crystal Structure of the [Cu(H2L1)2(Н2О)2] Complex

Russian Journal of General Chemistry ◽

10.1134/s1070363221110074 ◽

2021 ◽

Vol 91 (11) ◽

pp. 2176-2186

Author(s):

G. S. Tsebrikova ◽

Yu. I. Rogacheva ◽

I. S. Ivanova ◽

A. B. Ilyukhin ◽

V. P. Soloviev ◽

...

Keyword(s):

Crystal Structure ◽

Hydrogen Bond ◽

Methoxy Group ◽

Protonation Constants ◽

Water Molecules ◽

X Ray Diffraction ◽

X Ray ◽

The Stability ◽

Intramolecular Hydrogen ◽

Oxygen Atoms

Abstract 2-Hydroxy-5-methoxyphenylphosphonic acid (H3L1) and the complex [Cu(H2L1)2(H2O)2] were synthesized and characterized by IR spectroscopy, thermogravimetry, and X-ray diffraction analysis. The polyhedron of the copper atom is an axially elongated square bipyramid with oxygen atoms of phenolic and of monodeprotonated phosphonic groups at the base and oxygen atoms of water molecules at the vertices. The protonation constants of the H3L1 acid and the stability constants of its Cu2+ complexes in water were determined by potentiometric titration. The protonation constants of the acid in water are significantly influenced by the intramolecular hydrogen bond and the methoxy group. The H3L1 acid forms complexes CuL‒ and CuL24‒ with Cu2+ in water.

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Infrared Studies of Water in Crystalline Hydrates: Sodium Nitroprusside Dihydrate, Na2[Fe(CN)5NO]•2H2O

Canadian Journal of Chemistry ◽

10.1139/v71-233 ◽

1971 ◽

Vol 49 (9) ◽

pp. 1413-1424 ◽

Cited By ~ 33

Author(s):

Michaela Holzbecher ◽

Osvald Knop ◽

Michael Falk

Keyword(s):

Water Molecule ◽

Sodium Nitroprusside ◽

Infrared Spectra ◽

Structure Determination ◽

The Other ◽

Water Molecules ◽

Infrared Studies ◽

Increasing Temperature ◽

Crystalline Hydrates ◽

The Ideal

Infrared spectra of polycrystalline Na2[Fe(CN)5NO] 2H2O at different degrees of deuteration were studied as a function of temperature. The single peaks observed for the bending fundamentals of isotopically dilute H2O and D2O show that all the water molecules are equivalent, as required by Manoharan and Hamilton's structure determination; the doublets observed for the three fundamentals of isotopically dilute HDO show that the water molecules are asymmetric. Doublet separation decreases gradually with increasing temperature, indicating decreasing asymmetry. The water molecule appears to orient itself so as to maximize the strength of one [Formula: see text] bond, while the other OH group interacts only very weakly with another CN group. The hitherto unknown extent to which the nitroprusside ion deviates from the ideal C4v symmetry has been estimated from the 13C14N stretching spectrum. The 15N16O and 14N18O stretching spectrum was used to confirm that only one type of NO group is present in the crystal, and hence that all nitroprusside ions are equivalent.

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Engineering short, strong hydrogen bonds in urea di-carboxylic acid complexes

CrystEngComm ◽

10.1039/c4ce00587b ◽

2014 ◽

Vol 16 (35) ◽

pp. 8177-8184 ◽

Cited By ~ 17

Author(s):

Andrew O. F. Jones ◽

Charlotte K. Leech ◽

Garry J. McIntyre ◽

Chick C. Wilson ◽

Lynne H. Thomas

Keyword(s):

Hydrogen Bond ◽

Carboxylic Acid ◽

Hydrogen Bonds ◽

Neutron Diffraction ◽

Structural Changes ◽

Acid Amide ◽

Molecular Complexes ◽

Temperature Dependent ◽

X Ray ◽

Methyl Substitution

The persistence of the acid⋯amide heterodimer and the effect of methyl substitution on the short strong O–H⋯O hydrogen bond is investigated in urea and methylurea di-carboxylic acid molecular complexes. Temperature dependent structural changes are also reported utilising X-ray and neutron diffraction in tandem.

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