Go toArchive
Browse byFacets
Bookbag ( 0 )
'Hydrogen Bonds' in keywords Facet   section ZfN Section A  [X]
Results  17 Items
Sorted by   
Publication Year
2000 (3)
1999 (2)
1998 (1)
1996 (1)
1994 (1)
1993 (2)
1992 (4)
1991 (1)
1990 (2)
1Author    Snezhana BakalovaRequires cookie*
 Title     
 Abstract    o lv e n t E f fe c ts o n th e F lu o re s c e n c e P r o p e r tie s o f M e th y ld ih y d ro q u in o lin o n e s The absorption and fluorescence spectra and the fluorescence quantum yields of two methyl-2,3-dihydro-4(lH)-quinolinones in various solvents are reported. In some solvents deuteration-induced fluorescence enhancement has been observed. The solvent effects in aprotic solvents are consistent with the general type of solvent interaction. For protic solvents, solute-solvent complexation in the excited state is suggested. 
  Reference    Z. Naturforsch. 46a, 823—827 (1991); received May 24 1991 
  Published    1991 
  Keywords    Fluorescence, Dihydroquinolinones, Hydrogen bond 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/46/ZNA-1991-46a-0823.pdf 
 Identifier    ZNA-1991-46a-0823 
 Volume    46 
2Author    M. Grottel, A. Kozak, Z. PająkRequires cookie*
 Title    *H and 19 F NMR Study of Cation and Anion Motions in Guanidinium Hexafluorozirconate  
 Abstract    Proton and fluorine NMR second moments and spin-lattice relaxation times of polycrystalline guanidinium hexafluorozirconate and its deuterated analogue were studied in laboratory (60 MHz) and rotating (H, = 20 G) frames over a wide range of temperature. An analysis of the experimental results enabled us to reveal a dynamical inequivalence of two crystallographically independent cations and an unexpected high mobility of nonspherical anion dimers. A comparison of the ions dynamics in 2:1 complex studied with the guanidinium 1:1 and 3:1 complexes has shown a significant contribution of the hydrogen bonds to the potential barriers hindering the anion reorien-tations. At low temperatures a proton motion in the hydrogen bond and at 400 K a solid-solid phase transition have been discerned. 
  Reference    Z. Naturforsch. 51a, 991—996 (1996); received May 14 1996 
  Published    1996 
  Keywords    NMR, Ion Motions, Hydrogen Bonds, Phase Transitions 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0991.pdf 
 Identifier    ZNA-1996-51a-0991 
 Volume    51 
3Author    Nobuo Nakamura, Hirotsugo Masui, Takahiro UedaRequires cookie*
 Title    Effect of Intermolecular Hydrogen Bonding on the Nuclear Quadrupole Interaction in Imidazole and its Derivatives as Studied by ab initio Molecular Orbital Calculations  
 Abstract    Ab initio Hartree-Fock molecular orbital calculations were applied to the crystalline imidazole and its derivatives in order to examine systematically the effect of possible N-H---N type hydrogen bond-ing on the nuclear quadrupole interaction parameters in these materials. The nitrogen quadrupole coupling constant (QCC) and the asymmetry parameter (r?) of the electric field gradient (EFG) were found to depend strongly on the size of the molecular clusters, from single molecule, to dimer, trimer and to the infinite molecular chain, i.e., crystalline state, implying that the intermolecular N-H -N hydrogen bond affects significantly the electronic structure of imidazole molecule. A certain correla-tion between the QCC of l4 N and the N-H bond distance R was also found and interpreted on the basis of the molecular orbital theory. However, we found that the value of the calculated EFG at the hy-drogen position of the N-H group, or the corresponding QCC value of 2 H, increases drastically as /C* when R is shorter than about 0.1 nm, due probably to the inapplicability of the Gaussian basis sets to the very short chemical bond as revealed in the actual imidazole derivatives. We suggested that the ob-served N-H distances in imidazole derivatives should be re-examined. 
  Reference    Z. Naturforsch. 55a, 315—322 (2000); received August 26 1999 
  Published    2000 
  Keywords    Hydrogen Bond, Nuclear Quadrupole Interaction, Molecular Orbital, Imidazole 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/55/ZNA-2000-55a-0315.pdf 
 Identifier    ZNA-2000-55a-0315 
 Volume    55 
4Author    Taka-Aki Nihei, Shin'. Ichi, Ishimaru, Ryuichi IkedaRequires cookie*
 Title    C1 NQR Studies of Hydrogen Transfer in Crystalline /7-Chlorobenzoic Acid  
 Abstract    35 C1 NQR frequencies and spin-lattice relaxation times 7, Q were measured inp-ClC 6 H 4 C0 2 H(PCB A) and p-ClQF^CC^DtPCBA-d,) at 77-333 K. T lQ in PCB A gave a shallow minimum of 8.0 ms at ca. 110 K, which could be explained by a double proton transfer mechanism in the carboxylic acid dimer referring to *H NMR data giving a T 1H minimum at almost the same temperature. PCBA-d, showed temperature dependent NQR frequencies quite analogous to those in PCBA, whereas their r 1Q behavi-our was quite different in its minimum value and its temperature as well as temperature gradient. These results were explained by suppressed deuteron tunnelling and the Ubbelohde effect. 
  Reference    Z. Naturforsch. 55a, 355—358 (2000); received August 27 1999 
  Published    2000 
  Keywords    CI NQR, Hydrogen-Bond, Hydrogen-transfer, Tunneling 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/55/ZNA-2000-55a-0355.pdf 
 Identifier    ZNA-2000-55a-0355 
 Volume    55 
5Author    Masao Hashimoto, Akiko Shono, Yoshiyuki Mido, Haruo Niki, Hiroshi Hentona, Koichi ManoRequires cookie*
 Title    Narrowing of the 3 5 CI NQR Lines of Trichloroacetamide Caused by Its Ferroelectric Phase Transition  
 Abstract    Dielectric measurements on single crystals and DSC of the title compound (monoclinic, space group P2 X) revealed a ferroelectric transition at ca. 355 K (AH xs 0.5 kJ mol"Powder x-ray diffraction indicated that the high temperature phase is also monoclinic and the change in volume at the transition is very small. A displacement of hydrogen atoms is considered as responsible for the appearance of ferroelectricity. The 35 C1 NQR signals at ca. 77 K were considerably broad, but a drastic narrowing took place after the compound had once experienced the phase transition. A tentative assignment of the NQR spectrum was made from a calculation of the NQR frequencies based on the CNDO/2 method. Another phase transition was evidenced by a small drift of the DSC curve and a slight anomaly of the dielectric behavior around 358 K. The present *H NMR experi-ments gave no indication of the onset of torsional motion of the NH 2 group reported to occur at ca. 210 K. 
  Reference    Z. Naturforsch. 45a, 327—333 (1990); received August 26 1989 in revised form November 1 1989 
  Published    1990 
  Keywords    NQR, Phase transition, Ferroelectricity, Hydrogen bond, Disordered structure 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/45/ZNA-1990-45a-0327.pdf 
 Identifier    ZNA-1990-45a-0327 
 Volume    45 
6Author    Masao Hashimoto, Takahiro Isono, Haruo Niki, Takuya HigaRequires cookie*
 Title    Fade-Out of 35 C1 NQR in Chloral n-Butylhemiacetal  
 Abstract    Continuous wave and pulsed NQR, dielectric absorption and infrared (IR) measurements were carried out to investigate the origin of the peculiar temperature dependence of the S/N ratio of the 35 C1 NQR in the title compound. The dielectric and IR experiments evidenced a thermally activated jumping motion of the H atom participating in O-H O H-bonds. As T x and T 2 below 120 K were much longer than T 2 * of about 10 us, the line broadening in this temperature region was attributed to static lattice defects. A random freezing of the jumping motion may be the origin of the defects. In the range 120-170 K, S/N was extremely low and T 2 was less than 10 |is, probably having a minimum in between. The short T 2 is considered to be responsible for the low S/N. A minimum of S/N at about 240 K is attributed to a 7\ minimum (less than 10 (is) at that temperature. 
  Reference    Z. Naturforsch. 45a, 472—476 (1990); received August 26 1989 in revised form December 1 1989 
  Published    1990 
  Keywords    NQR, Relaxation times, Hydrogen bond, Dielectric absorption, Disordered structure 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/45/ZNA-1990-45a-0472.pdf 
 Identifier    ZNA-1990-45a-0472 
 Volume    45 
7Author    Takashige Shimizu, Tetsuo Asaji, Daiyu Nakamura, Ryuichi IkedaRequires cookie*
 Title    Uniaxial Reorientation of Octahedral Complex Anions Excited in Triethylammonium Hexachlorostannate (IV) Crystals  
 Abstract    The temperature dependence of the 35 C1 NQR spin-latticew relaxation time T1Q has been deter-mined for the three resonance lines observed in [(C2H5)3NH]2SnCl6. The higher frequency lines fade out around 150 K upon heating, whereas the lowest line shows up to room temperature no anomaly, although these three lines are assigned to chlorines belonging to the same complex anion. The T1Q values of the higher two lines decrease exponentially around the fade-out temperature, where T iq of the lowest line shows no such behavior. These results are explained by the onset of uniaxial reorientations of the octahedral complex ions by 90° about the Cl-Sn-Cl axis containing the lowest frequency chlorines. The activation energy (£J of this reorientation (22-24 kJ moP 1) is the lowest so far reportd for [SnCl6] 2-ions. £a about the other axes is 67 kJ mop 1 , indicating a remarkable anisotropic reorientation. 
  Reference    Z. Naturforsch. 47a, 283—287 (1992); received July 19 1991 
  Published    1992 
  Keywords    Spin-Lattice Relaxation, NQR, NMR, Reorientational Motion, Hydrogen Bond 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/47/ZNA-1992-47a-0283.pdf 
 Identifier    ZNA-1992-47a-0283 
 Volume    47 
8Author    Yoshio Kume, Maki Tokoro, Tetsuo Asaji, Ryuichi Ikeda, Daiyu NakamuraRequires cookie*
 Title    Reorientational Motion of Hydrogen Bonded Octahedral Complex Anions in Hydrazinium Hexachlorostannate(IV), (N 2 H 5 ) 2 SnCl 6 , as Studied by 35 C1 NQR Spin-Lattice Relaxation Measurements  
 Abstract    The temperature dependences of NQR frequencies and spin-lattice relaxation times, T1Q, of 35 C1 in (N2H5)2SnCl6 were measured. Four NQR signals distributed in a fairly wide frequency range were observed, the lowest-frequency line exhibiting an anomalous positive temperature coefficient. The highest-frequency line showed a steep temperature dependence. These results could be interpreted by considering the intermolecular interaction between CI and -NH2 in N2H^. Below ca. 250 K, T1Q of the upper three signals exhibited a gradual decrease upon heating, explainable by lattice vibra-tions, while a shallow Tig minimum, ascribable to the modulation of electric quadrupole interaction, was observed at ca. 11ÖK for the lowest-frequency signal. The reorientation of [SnCl6] 2 ~ was elucidated to be highly anisotropic, in that it reorients about one of the CI-Sn-Cl axes much more frequently than about the other two axes. The activation energies were determined to be 62 and 94 kj mol -1 for the respective reorientations. 
  Reference    Z. Naturforsch. 47a, 288—292 (1992); received July 17 1991 
  Published    1992 
  Keywords    Key word: Spin-Lattice Relaxation, NQR, NMR, Reorientational Motion, Hydrogen Bond 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/47/ZNA-1992-47a-0288.pdf 
 Identifier    ZNA-1992-47a-0288 
 Volume    47 
9Author    Takeshi Kyan, Hamagawa, Takahiro Isono, Masao HashimotoRequires cookie*
 Title    Hiroshi  
 Abstract    The crystal structure of cyclohexylhemiacetal (cycHx-CH) was determined at 296 K: monoclinic, space group P2 Jc, a =1028.7 (9), b = 609.5 (1), c = 1811.9 (4) pm, and ß = 99.79 (3)°, Z -4, R = 0.0552. The three 5s Cl NQR lines in cycHx-CH, T., T2, and T2*, were measured by a pulsed method at 80-300 K. Below 200 K Tf 1 obeyed the T law well, indicating that the spin lattice relaxation is governed by lattice vibrations. The reorientation of CC13 seems to be responsible for the sharp T: drop observed above 250 K. Shoulders in the T { vs. 1/T curves indicate the presence of Ti minima at about 240 K. A fluctuation of the EFG due to a dynamic disorder of hydrogen atoms in the OH groups is assumed to explain the T x minima. 
  Reference    Z. Naturforsch. 47a, 299 (1992); received July 25 1991 
  Published    1992 
  Keywords    Chlorine NQR, Spin-lattice relaxation, Hydrogen bond, Crystal structure 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/47/ZNA-1992-47a-0299.pdf 
 Identifier    ZNA-1992-47a-0299 
 Volume    47 
10Author    Ivar Olovsson, Halina Ptasiewicz-Bak, GarryJ. MclntyreRequires cookie*
 Title    Superposition and Polarization Effects on the Electron Density of Lone Pairs  
 Abstract    There appears to be conflicting experimental evidence on the redistribution of the electron density in the lone-pair and other regions of a molecule due to the interaction with its nearest neighbours. In some experimental as well as theoretical deformation density maps a decrease in the lone-pair density has been reported, whereas in other cases an increase has been found. It appears that two major, counteracting factors are responsible for these differences (apart from experimental errors in the diffraction studies and limited accuracy in the theoretical calculations): an increase in the lone-pair density is expected due to the polarizing influence of the neighbours, whereas simple superposition of the isolated monomer deformation densities will lead to an apparent decrease due to the overlap with the negative contours of the neighbouring atom. Depending on which of these factors is the dominant one, an increase or decrease may thus be observed. These points are illustrated by recent results on nickel sulfate hexahydrate and some other hydrogen-bonded compounds. The electron density based on the fitted deformation functions of all atoms in the structure is compared with the individual densities calculated from deformation functions of the separate monomers. In this way the effects of simple superposition of the individual densities have been studied, and a partitioning of the electrostatic and polarization contributions to the hydrogen bonds and other relatively weak bonds to the oxygen lone-pairs attempted. 
  Reference    Z. Naturforsch. 48a, 3—11 (1993); received January 30 1992 
  Published    1993 
  Keywords    Electron density, Superposition effects, Polarization effects, Lone pairs, Hydrogen bonds 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/48/ZNA-1993-48a-0003.pdf 
 Identifier    ZNA-1993-48a-0003 
 Volume    48 
11Author    Masao Hashimoto, Shuji Matsumoto, Masakazu Kunitomo, Haruo Niki, Hirotaka Odahara, Katsuji TamakiRequires cookie*
 Title    35C1 NQR Relaxation and Hydrogen Bond in Some Chloral Hemiacetals  
 Abstract    The crystal structure of chloral ethylhemiacetal has been determined at 291 K: monoclinic, space group C f -P 2 lt Z = 2, a = 854.5(1), b = 594.0(3), c = 853.3(1) pm, ß = 108.30(2)°, R = 0.0962. A sharp decrease of the spin lattice relaxation time 7i found for the 35C1 N Q R o f the CC13 groups in chloral methyl-, ethyl-and n-heptylhemiacetals is attributed to the onset of reorientation of the group over a potential barrier o f ca. 39, 37, and 32 kJ/m ol, respectively. An unusual vs. 1/T curve with a 7i minimum superimposed on the sharp decrease of 7\ due to the reorientation was observed for each of the three Cl N Q R lines of nH p-C H . This phenom enon is tentatively ascribed to a fluctuation of EFG caused by jum ping m otion o f the hydrogen atom s in the OH groups. 
  Reference    Z. Naturforsch. 49a, 279 (1994); received August 16 1993 
  Published    1994 
  Keywords    Crystal structure, Hydrogen bond, Chlorine N Q R, Spin lattice relaxation 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/49/ZNA-1994-49a-0279.pdf 
 Identifier    ZNA-1994-49a-0279 
 Volume    49 
12Author    J.M M CordeiroRequires cookie*
 Title    Effective Pair Potentials and Structure of Water  
 Abstract    Classical Monte Carlo calculations have been performed in order to investigate the ability of the TIP4P, SPC, and SPCE water models to reproduce the structural features of liquid water. The simula-tions were carried out in the NPT ensemble at 4 thermodynamic conditions. The results are compared with recent neutron diffraction data. Essentially, the three models capture equally well the thermody-namic and structural features of water. Although they were parametrized to reproduce the water prop-erties at ambient conditions, the agreement with the experimental pair correlation functions was even better at supercritical conditions. This is because the effective pair potentials have some difficulty to re-produce cooperative interactions, like hydrogen bonds. These interactions are less effective at super-critical conditions, where the liquid behaves roughly like a gas 
  Reference    Z. Naturforsch. 54a, 311—316 (1999); received December 16 1998 
  Published    1999 
  Keywords    Monte Carle Simulation, Non-polarizable Water Models, Radial Distribution Functions, Hydrogen-bonds 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0311.pdf 
 Identifier    ZNA-1999-54a-0311 
 Volume    54 
13Author    Masao Hashimoto, Takahiro Isono, Noriko Yomesaka, Haruo Niki, Hiroshi Kyan, Takeshi HamagawaRequires cookie*
 Title    Reorientation of the CC1 3 Group in Chloral 4-Chlorobenzyl- hemiacetal. A Pulsed 35 C1 NQR and X-ray Study  
 Abstract    The crystal structure of the title compound was determined at 291 K: monoclinic, space group C^h-P21/n, Z = 4, a = 1693.2(1), 6 = 579.3(1), c = 1232.5(1) pm, and ß = 107.21 (1)°, R = 0.0415. A sharp decrease of of Cl NQR found at T> 270 K for the CC13 group is attributed to the reorientation of the group over a potential barrier of ca. 50 kJ/mol. Intermolecular interactions between the CC13 and the neighboring atoms seem to dominate the magnitude of the potential barrier. T{~ 1 of the 35 C1 NQR of the Cl atom on the benzene ring obeyed the T 2 law well in the range 80 < T/K <270, while at T>280 K it deviated from the T 2 law. 
  Reference    Z. Naturforsch. 47a, 293—298 (1992); received July 25 1991 
  Published    1992 
  Keywords    Crystal structure, Hydrogen bond, Chlorine NQR, Spin lattice relaxation, Atom-atom potential method 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/47/ZNA-1992-47a-0293.pdf 
 Identifier    ZNA-1992-47a-0293 
 Volume    47 
14Author    B. N. Figgis, E. S. Kucharski, M. VrtisRequires cookie*
 Title    Spin Transfer through Hydrogen Bonding in [CO(NH 3 ) S (OH 2 )| |Cr(CN) 6 | ?  
 Abstract    A polarised-neutron diffraction experiment on [Co(NH 3) 5 (H 2 0)][Cr(CN) 6 ] shows the unexpected features of spin populations on the cobalt ((0.5(2) e) and the "ammine" hydrogen (0.8(1) e in total) atoms. A local density approximation DV-Xa calculation on a unit that models the molecular geometry in the crystal returns features that are broadly in agreement with the experiment. The calculation also reproduces the major features of a charge density experiment on the complex, including the low (+1.6 e) charges on the ions, in place of the formal ±3 e. 
  Reference    Z. Naturforsch. 48a, 123—126 (1993); received October 14 1991 
  Published    1993 
  Keywords    Spin density, Hydrogen bond, Local density approximation calculation, Charge den-sity, Spin transfer 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/48/ZNA-1993-48a-0123.pdf 
 Identifier    ZNA-1993-48a-0123 
 Volume    48 
15Author    Hiroshi Miyoshi, Keizo Horiuchi, Narumi Sakagami, Kenichi Okamoto, Ryuichi IkedaRequires cookie*
 Title    C1 NQR, *H NMR, and X-Ray Diffraction Studies in a Hydrogen Bonded Complex Na 2 PtCl 6 * 6H z O  
 Abstract    The 35 C1 NQR frequencies, spin-lattice relaxation time and X H NMR relaxation time were measured on crystalline Na 2 PtCl 6 • 6H z O at 77-350 K. The presence of three nonequivalent chlo-rine sites found by X-ray diffraction measurement is in agreement with the observed three NQR lines, which have different temperature dependences attributable to differences in the direction of H-bonding with water molecules. The three NQR lines correspond to three kinds of chlorines with different Pt-Cl distances and H-bond directions. 
  Reference    Z. Naturforsch. 53a, 603—607 (1998); received October 31 1997 
  Published    1998 
  Keywords    CI NQR, X-Ray Diffraction, Spin-Lattice Relaxation, Quadrupole Coupling Constant, Hydrogen Bond 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/53/ZNA-1998-53a-0603.pdf 
 Identifier    ZNA-1998-53a-0603 
 Volume    53 
16Author    Takahiro Ueda, Shigenori Nagatomo, Hirotsugu Masui, Nobuo Nakamura, Shigenobu HayashiRequires cookie*
 Title    Hydrogen Bonds in Crystalline Imidazoles Studied by 15 N NMR and ab initio MO Calculations  
 Abstract    Intermolecular hydrogen bonds of the type N-H...N in crystals of imidazole and its 4-substituted and 4,5-disubstituted derivatives were studied by 15 N CP/MAS NMR and an ab initio molecular orbital (MO) calculation. In the 15 N CP/MAS NMR spectrum of each of the imidazole derivatives, two peaks due to the two different functional groups, >NH and =N-, were observed. The value of the I 5 N isotrop-ic chemical shift for each nitrogen atom depends on both the length of the intermolecular hydrogen bond and the kind of the substituent or substituents. It was found that the difference between the experimen-tal chemical shifts of >NH and =N-varies predominantly with the hydrogen bond length but does not show any systematic dependence on the kind of substituent. The ab initio MO calculations suggest that the hydrogen bond formation influences the 15 N isotropic chemical shift predominantly, and that the difference between the 15 N isotropic chemical shift of >NH and =N-varies linearly with the hydrogen bond length. 
  Reference    Z. Naturforsch. 54a, 437—442 (1999); received March 31 1999 
  Published    1999 
  Keywords    15 N CP/MAS NMR, Imidazoles, Hydrogen Bond, 15 N Chemical Shift, ab initio MO Calculation 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0437.pdf 
 Identifier    ZNA-1999-54a-0437 
 Volume    54 
17Author    Takahiro Ueda, Nobuo NakamuraRequires cookie*
 Title    Nature of Hydration Water in (±)-Tris(ethylenediamine)cobalt(III) Chloride Hydrate, (±)-[Co(en) 3 ]Cl 3 -/iH 2 0, as Studied by *H, 2 H, and 17 O Solid State NMR  
 Abstract    The static and dynamics properties of hydration water molecules in (±)-[Co(en) 3 ]Cl 3 were studied by means of 'H, 2 H, and ,7 0 solid state NMR. By 'H pulsed field gradient (PFG) NMR the apparent diffusion coefficient of mobile water through a micropore along the crystalline unique c-axis was found to be 1.0 x 10~ 9 m 2 s -1 . The 2 H NMR spectrum at 141 K consists of two components, one being a Pake doublet corresponding to a quadrupole coupling constant (QCC) of (226 ± 2) kHz and an asymmetry parameter of the electric field gradient 77 of 0.08 ± 0.01, and another being a Gaussian line with a linewidth of 3.5 kHz. The 17 0 NMR spectrum at 300 K also consists of a narrow Gaussian peak and a broad powder pattern with a second order quadrupole effect corresponding to QCC = (6.3 ± 0.5) MHz and 77 = 0.55±0.02. The broad and narrow components are assigned to water molecules accommodated at general 12g positions and special 2a and 2b positions in the trigonal lattice with space group Plcl. From the ratio of the populations at these positions their potential energy difference was estimated to be between (2.7 ±0.1) and (3.5 ± 0.1) kJmol -1 . The 2 H NMR spectrum at room temperature indicates a finite quadrupole interaction which is attributable to the rapid rotation of water molecule about the molecular C 2 -axis. When the water content exceeds 2.7, the QCC is reduced sharply to (5.0 ±0.1) kHz at 285 K, suggesting that there occurs rapid rotation of water and rapid exchange of 2 H between nonequivalent positions. 
  Reference    Z. Naturforsch. 55a, 362—368 (2000); received August 23 1999 
  Published    2000 
  Keywords    (±)-[Co(en) 3 ]Cl 3, Absorbed Water, Molecular Motion, Hydrogen Bond, Quadrupole Interaction 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_A/55/ZNA-2000-55a-0362.pdf 
 Identifier    ZNA-2000-55a-0362 
 Volume    55