Nitronyl Nitroxide Substituted Anilineo-APNN with a Three-dimensional Hydrogen Bond Network Showing Ferromagnetic Interaction

2003 ◽  
Vol 32 (6) ◽  
pp. 544-545 ◽  
Author(s):  
Kentaro Doi ◽  
Takayuki Ishida ◽  
Takashi Nogami
Keyword(s):  
Hydrogen Bond ◽  
Three Dimensional ◽  
Hydrogen Bond Network ◽  
Nitronyl Nitroxide ◽  
Ferromagnetic Interaction ◽  
Bond Network

(NH4)[B3PO6(OH)3]·0.5H2O

2007 ◽  
Vol 63 (11) ◽  
pp. i185-i185 ◽  
Author(s):  
Wei Liu ◽  
Jingtai Zhao
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Water Molecules ◽  
Hydrogen Bond Network ◽  
Ammonium Ions ◽  
One Dimensional ◽  
Bond Network ◽  
Solvothermal Conditions

The title compound, ammonium catena-[monoboro-monodihydrogendiborate-monohydrogenphosphate] hemihydrate, was obtained under solvothermal conditions using glycol as the solvent. The crystal structure is constructed of one-dimensional infinite borophosphate chains, which are interconnected by ammonium ions and water molecules via a complex hydrogen-bond network to form a three-dimensional structure. The water molecules of crystallization are disordered over inversion centres, and their H atoms were not located.

scholarly journals (Acetonitrile-κN)aqua[N,N′-bis(pyridin-2-ylmethyl)ethane-1,2-diamine-κ4N,N′,N′′,N′′′]zinc(II) perchlorate

2017 ◽  
Vol 73 (10) ◽  
pp. 1568-1571
Author(s):  
Ugochukwu Okeke ◽  
Yilma Gultneh ◽  
Ray J. Butcher
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Three Dimensional ◽  
Structural Features ◽  
Hydrogen Bond Network ◽  
Asymmetric Unit ◽  
Bond Network ◽  
Bifurcated Hydrogen Bond ◽  
Coordinated Water ◽  
Ionic Hydrogen Bonding

The structure of the title compound, [Zn(C14H18N4)(C2H3N)(H2O)](ClO4)2, contains a six-coordinate cation consisting of the tetradentate bispicen ligand, coordinated water, and coordinated acetonitrile, with the latter two ligands adopting acisconfiguration. There are two formula units in the asymmetric unit. Both cations show almost identical structural features with the bispicen ligand adopting the more commoncis-β conformation. One of the four perchlorate anions is disordered over two positions, with occupancies of 0.9090 (15) and 0.0910 (15). There is extensive inter-ionic hydrogen bonding between the perchlorate anions and O—H and N—H groups in the cations, including a bifurcated hydrogen bond between an N—H group and two O atoms of one perchlorate anion. As a result of this extended hydrogen-bond network, the ions are linked into a complex three-dimensional array.

scholarly journals Reorientation-induced relaxation of free OH at the air/water interface revealed by ultrafast heterodyne-detected nonlinear spectroscopy

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Ken-ichi Inoue ◽  
Mohammed Ahmed ◽  
Satoshi Nihonyanagi ◽  
Tahei Tahara
Keyword(s):  
Hydrogen Bond ◽  
Vibrational Relaxation ◽  
Three Dimensional ◽  
Technical Difficulty ◽  
Nonlinear Spectroscopy ◽  
Water Interface ◽  
Hydrogen Bond Network ◽  
Relaxation Dynamics ◽  
Air Water Interface ◽  
Bond Network

Abstract The uniqueness of water originates from its three-dimensional hydrogen-bond network, but this hydrogen-bond network is suddenly truncated at the interface and non-hydrogen-bonded OH (free OH) appears. Although this free OH is the most characteristic feature of interfacial water, the molecular-level understanding of its dynamic property is still limited due to the technical difficulty. We study ultrafast vibrational relaxation dynamics of the free OH at the air/water interface using time-resolved heterodyne-detected vibrational sum frequency generation (TR-HD-VSFG) spectroscopy. With the use of singular value decomposition (SVD) analysis, the vibrational relaxation (T1) times of the free OH at the neat H2O and isotopically-diluted water interfaces are determined to be 0.87 ± 0.06 ps (neat H2O), 0.84 ± 0.09 ps (H2O/HOD/D2O = 1/2/1), and 0.88 ± 0.16 ps (H2O/HOD/D2O = 1/8/16). The absence of the isotope effect on the T1 time indicates that the main mechanism of the vibrational relaxation of the free OH is reorientation of the topmost water molecules. The determined sub-picosecond T1 time also suggests that the free OH reorients diffusively without the switching of the hydrogen-bond partner by the topmost water molecule.

A hydrogen-bond network at the active site of subtilisin BPN'

1970 ◽  
Vol 257 (813) ◽  
pp. 119-124 ◽  
Keyword(s):  
Hydrogen Bond ◽  
Active Site ◽  
Serine Proteases ◽  
Catalytic Mechanism ◽  
Three Dimensional ◽  
Hydrogen Bond Network ◽  
The Common ◽  
Bond Network ◽  
The One ◽  
Active Site Region

Further examination of the active site region in our X-ray crystallographic model of subtilisin BPN' reveals a hydrogen-bond network that bears a remarkable resemblance to the one found in a- chymotrypsin. It involves the side chains of the reactive Ser-221, His-64, Asp-32 and Ser-33. Otherwise the two enzymes have entirely different three-dimensional structures. This observation suggests that the common hydrogen bond network plays some essential role in the catalytic mechanism of serine proteases generally.

Two polymorphs of bis(2-carbamoylguanidinium) fluorophosphonate dihydrate

2012 ◽  
Vol 68 (2) ◽  
pp. o71-o75 ◽  
Author(s):  
Jan Fábry ◽  
Michaela Fridrichová ◽  
Michal Dušek ◽  
Karla Fejfarová ◽  
Radmila Krupková
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Water Molecule ◽  
Three Dimensional ◽  
Mirror Plane ◽  
Water Molecules ◽  
Hydrogen Bond Network ◽  
Hydrogen Bond Networks ◽  
Bond Network ◽  
Graph Set

Two polymorphs of bis(2-carbamoylguanidinium) fluorophosphonate dihydrate, 2C2H7N4O+·FO3P2−·2H2O, are presented. Polymorph (I), crystallizing in the space groupPnma, is slightly less densely packed than polymorph (II), which crystallizes inPbca. In (I), the fluorophosphonate anion is situated on a crystallographic mirror plane and the O atom of the water molecule is disordered over two positions, in contrast with its H atoms. The hydrogen-bond patterns in both polymorphs share similar features. There are O—H...O and N—H...O hydrogen bonds in both structures. The water molecules donate their H atoms to the O atoms of the fluorophosphonates exclusively. The water molecules and the fluorophosphonates participate in the formation ofR44(10) graph-set motifs. These motifs extend along theaaxis in each structure. The water molecules are also acceptors of either one [in (I) and (II)] or two [in (II)] N—H...O hydrogen bonds. The water molecules are significant building elements in the formation of a three-dimensional hydrogen-bond network in both structures. Despite these similarities, there are substantial differences between the hydrogen-bond networks of (I) and (II). The N—H...O and O—H...O hydrogen bonds in (I) are stronger and weaker, respectively, than those in (II). Moreover, in (I), the shortest N—H...O hydrogen bonds are shorter than the shortest O—H...O hydrogen bonds, which is an unusual feature. The properties of the hydrogen-bond network in (II) can be related to an unusually long P—O bond length for an unhydrogenated fluorophosphonate anion that is present in this structure. In both structures, the N—H...F interactions are far weaker than the N—H...O hydrogen bonds. It follows from the structure analysis that (II) seems to be thermodynamically more stable than (I).

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