L-histidine Hydrochloride Monohydrate Research Articles

High-pressure Raman spectra of l-histidine hydrochloride monohydrate crystal

Single-crystals of l-histidine hydrochloride monohydrate, C 6H 9N 3O 2·HCl·H 2O, were studied by Raman spectroscopy as a function of pressure in a diamond anvil cell up to 7.5 GPa at room temperature over the spectral range 3450–30 cm −1. The effect of changing pressure on the vibrational spectrum is discussed. From the analysis of results we inferred that the crystal undergoes a reversible structural phase transition between 2.7 and 3.1 GPa. This transition is characterized by the splitting of a band related to torsion of CO 2 −, the disappearance and appearance of modes related with stretching of OH − and deformation of CO 2 −, as well as with bands of low wavenumber which are assigned as lattice modes, and by the discontinuities of the curves of wavenumber versus pressure. Pressure coefficients for all modes observed in this work are also given.

Crystal growth and characterization of semiorganic single crystals of l-histidine family for NLO applications

Single crystals of l-histidine hydrochloride monohydrate and tartaric acid mixed l-histidine hydrochloride monohydrate have been grown by slow evaporation solution growth technique from appropriate mixtures of respective chemicals. Single crystal and powder X-ray diffraction analyses, Fourier transform infrared, nuclear magnetic resonance spectral analysis, thermo-gravimetric (TG), differential thermal analysis (DTA) have been employed to characterize the as-grown crystals. It is observed to be a wide transparency window for both the crystals from 300 to 1000 nm, which is suitable for second harmonic generation of laser in the blue region. Nonlinear optical characteristics have been studied using Q switched Nd: YAG laser ( λ=1064 nm). The second harmonic generation conversion efficiency of the grown crystal shows the suitability for frequency conversion applications.

Spectral, optical and mechanical studies on l-histidine hydrochloride monohydrate (LHC) single crystals grown by unidirectional growth technique

Single crystals of nonlinear optical l-histidine hydrochloride monohydrate (LHC) were grown in an aqueous solution by the unidirectional crystal growth method within a period of 45 days along (1 0 1) plane. The grown crystals were subjected to single crystal X-ray diffraction analysis to confirm their orthorhombic structure having space group P2 12 12 1. Values of several physical parameters were determined for the grown crystal. Optical transmission studies revealed very low absorption and band gap energy was calculated for the LHC crystals. Further, some optical constant were also determined for the grown crystals. Anisotropy in Vicker's microhardness led to the assessment of fracture toughness, brittleness index and yield strength for the synthesized crystals. Nonlinear optical studies were carried out for the grown crystal and second harmonic generation (SHG) efficiency was found to be three times that of KDP crystals.

Estimation of internuclear couplings in the solid-state NMR of multiple-spin systems. Selective spin echoes and off-magic-angle sample spinning

Internuclear couplings between selected homonuclear spin pairs in a multiply-labelled spin system are determined by NMR spin echo experiments in the solid-state. The spin echoes are induced by an amplitude-modulated shaped pulse. The time shift in the echo modulation curve is treated by average Hamiltonian theory and verified by numerical simulation. The J-couplings may be estimated by experiments on samples spinning at the magic-angle, while the direct dipole–dipole couplings may be estimated by off-magic-angle spinning. The concept is tested on a uniformly 13C-enriched sample of l-histidine hydrochloride monohydrate.

Piezoelectric coefficients of L-histidine hydrochloride monohydrate obtained by synchrotronx-ray Renninger scanning

The method for determining piezoelectric coefficients based on synchrotronradiation x-ray multiple diffraction (Avanci et al 1998 Phys. Rev. Lett. 815426) has been used in the case of a single crystal of the amino acidL-histidine·HCl·H2O. The methodrelates the E-induced strain with the angular shift in the multiple diffractionpeak position. Thus, it allowed us to determine all three(d14 = 2.25(9) × 10−10 C N−1,d25 = 4.1(5) × 10−11 C N−1 andd36 = 2.3(2) × 10−10 C N−1) piezoelectriccoefficients of L-histidine·HCl·H2O, using the (10 0 0) and (0 0 4) primary reflections.

Deuterium Quadrupolar Tensors of l-Histidine Hydrochloride Monohydrate-d7

A deuterium NMR study at 14 T of a single crystal of L-histidine hydrochloride monohydrate has determined the deuteron quadrupole coupling constants CQ, asymmetry parameters eta, and electric field gradient orientation for the imidazolium and primary ammonium groups and for a water of crystallization. The imidazolium deuterons, which have very long relaxation times, have quite different coupling constants, reflecting different hydrogen bonding but nearly identical orientations, with the most distinct principal axis in both cases nearly parallel to the N-D vector. The -ND3 groups undergo 3-fold hops about the C-N bond axis and have typical quadrupole couplings; the D2O undergoes 2-fold hops, leading to a tensor with a large asymmetry parameter. With appropriate corrections for vibrational averaging, density functional cluster calculations give an excellent fit to the imidazolium tensor magnitudes and orientations.

Raman spectra of L‐histidine hydrochloride monohydrate crystal

AbstractSingle‐crystal samples of L‐histidine hydrochloride monohydrate (LHICL), C6H9N3O2·HCl·H2O, were studied by Raman spectroscopy at temperatures ranging from 295 to 40 K over the spectral range 20–3400 cm−1. A tentative assignment of the bands is given. The effect of temperature change on the vibrational spectrum is discussed. The behavior of the Raman spectra, in particular the emergence of new modes in the low‐wavenumber region, indicates that LHICL undergoes a structural phase transition between 140 and 110 K. There are further indications that, possibly, a second change of structure occurs for temperatures between 80 and 60 K. Copyright © 2004 John Wiley & Sons, Ltd.

Double Nuclear Coherence Transfer (DONUT)-HYSCORE: A New Tool for the Assignment of Nuclear Frequencies in Pulsed EPR Experiments

A two-dimensional experiment, termed DONUT-HYSCORE (double nuclear coherence transfer hyperfine sublevel correlation) designed to obtain correlations between nuclear frequencies belonging to the same electron spin manifold is presented. The sequence employed is π/2−τ1−π/2−t1−π−τ2−π−t2−π/2−τ1−echo, and the echo is measured as a function of t1 and t2 whereas τ1 and τ2 are held constant. It is complementary to the standard HYSCORE experiment which generates correlations between nuclear frequencies belonging to different MS manifolds and is particularly useful for 14N nuclei. The experiment is first demonstrated on a single crystal of copper-doped l-histidine hydrochloride monohydrate where the modulations are induced by a single 14N nucleus, the remote nitrogen in the imidazole group. HYSCORE and DONUT-HYSCORE experiments were carried out on two crystal orientations. In the first, one Cu2+ site contributes to the echo and all six nuclear frequencies together with the expected correlation were observed. In the second, 12 frequencies corresponding to two Cu2+ ions at different crystallographic sites appeared and all expected correlations were detected as well. This rather trivial example demonstrates that the DONUT-HYSCORE pulse sequence indeed generates correlations within the MS manifolds. The value of the DONUT-HYSCORE experiment is demonstrated on a frozen solution of a vanadyl complex with a bis-hydroxamate ion binder (VO-RL515). The modulations in this complex arise from the two 14N nuclei in the hydroxamate groups, and orientation-selective three-pulse ESEEM (electron spin−echo envelope modulation) spectra showed a number of well-resolved peaks. An unambiguous assignment of all peaks and their orientation dependences could not be achieved through HYSCORE alone because at certain orientations frequencies of one of the MS manifolds were absent or overlapped with those of the other manifold. The application of the DONUT-HYSCORE experiment provided new correlations that led to the complete assignment of the ESEEM frequencies, thus paving the way for future systematic spectral simulations for the determination of the best-fit Hamiltonian parameters. This example shows that, in the case that the HYSCORE experiment cannot distinguish between two sets of frequencies belonging to the same MS manifold in different centers (or orientations) because signals from the other manifold are missing or overlapping, the DONUT-HYSCORE becomes most valuable.

An electron spin-echo envelope modulation study of copper(II)-doped single crystals of L-histidine hydrochloride monohydrate

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAn electron spin-echo envelope modulation study of copper(II)-doped single crystals of L-histidine hydrochloride monohydrateMichael J. Colaneri and Jack PeisachCite this: J. Am. Chem. Soc. 1992, 114, 13, 5335–5341Publication Date (Print):June 1, 1992Publication History Published online1 May 2002Published inissue 1 June 1992https://doi.org/10.1021/ja00039a051RIGHTS & PERMISSIONSArticle Views178Altmetric-Citations47LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (870 KB) Get e-Alerts Get e-Alerts

Determination of the 14N quadrupole coupling tensors in a single crystal of l-histidine hydrochloride monohydrate by NMR spectroscopy

The 14N quadrupole coupling tensors of the NH 3 +, N2, and N3 nitrogen nuclei in a single crystal of l-histidine hydrochloride monohydrate were determined using proton enhanced 14N NMR with high-power proton decoupling. The signs of the 14N quadrupole coupling constant, e 2Qg h , for the three chemically distinct nitrogen nuclei could be determined by analyzing the lineshapes of the 13C CP-MAS NMR signals of the C2, C4, and C6 carbon nuclei which are directly bonding to one of those nitrogen nuclei. The 14N quadrupole coupling constants including their signs and the asymmetry parameters, η, were evaluated to be e 2Qg h = 1.147 MHz and η = 0.189 for the NH 3 + nitrogen nucleus, e 2Qg h = 1.465 MHz and η = 0.268 for the N2 nitrogen nucleus, and e 2Qg h = −1.287 MHz and η = 0.946 for the N3 nitrogen nucleus. The direction of the largest principal axis of the 14N quadrupole coupling tensor for the NH 3 + nitrogen nucleus is almost parallel to the NlC2 bond direction, while that for the N2 nitrogen nucleus makes an angle of 33° with the N2C4 bond direction in the C4N2C5 plane, and for the N3 nitrogen nucleus it is perpendicular to the C5N3C6 plane. Application of the Townes and Dailey model shows the orbital populations of the p μ and the NH orbitals are larger than those of the NC orbital of the N2 and N3 nitrogen nuclei. The difference between the 14N quadrupole coupling tensors of N2 and N3, can be attributed to the difference in the hydrogen bonding at those two sites.

The kinetics of radical decay in crystalline amino acids. 7. Monohydrates

The kinetics of radical decay in x-irradiated single crystals of L-arginine hydrochloride monohydrate, L-asparagine monohydrate, and L-histidine hydrochloride monohydrate have been studied. At temperatures sufficiently low that no measurable dehydration occurs, radical decay fits a model which includes distinct activation energies for the combination of nearby radicals and for diffusion of distant radicals to within a critical reaction distance. At temperatures sufficiently high that significant dehydration occurs on the time scale of radical decay, two types of behavior were observed. In L-asparagine monohydrate and L-histidine hydrochloride monohydrate, radical decay became rapid only upon completion of dehydration, whereas in L-arginine hydrochloride monohydrate radical decay became rapid at the start of dehydration and was completed well before dehydration was complete. At intermediate temperatures the radical decay kinetics appear to be a combination of the diffusion-controlled process and the dehydration-assisted one. No radical conversions were observed during decay.

Neutron diffraction study of L-histidine hydrochloride monohydrate

Neutron diffraction study of L-histidine hydrochloride monohydrate

Nuclear quadrupole resonance of 14N in imidazole and related compounds

Using the technique of nuclear double resonance with spin mixing by level crossing, the nuclear quadrupole resonance of 14N has been measured in L-histidine, D-L-histidine, L-histidine hydrochloride monohydrate, sodium urocanate and urocanic acid at 77 K. The nuclear quadrupole resonance of both 14N and 2D has been measured in deuterated imidazole at 77 K. The previously measured spectra for normal imidazole have been positively assigned with the electric field gradient parameters for the tri-coordinated nitrogen site given by e 2 qQ/h = 1424 kHz and η = 0.980, and for the di-coordinated nitrogen site by e 2 qQ/h = 3267 kHz and η = 0.129.

Electron Paramagnetic Resonance and Polarized Absorption Spectra of Cu(II)-Doped Single Crystal of L-Histidine Hydrochloride Monohydrate

The electron paramagnetic resonance of copper(II) doped in a single crystal of L-histidine· HCl monohydrate indicates that the Cu2+ ion is incorporated in a different environment from that in the ordinary bis(L-histidinyl)copper(II) complex. The coefficients of the ground state Kramer's doublet were determined from the observed g tensor (gz = 2.013, gx = 2.262, gv = 2.153) in such a way that the hyperfine parameters calculated from the coefficients closely reproduce the observed values. The results show that the half-filled d orbital is of the dz2 type, suggesting an axially compressed structure. The polarized single crystal absorption spectra taken in the three perpendicular crystal faces exhibit three d-d transitions at 14 000, 12 800 and 11 100 cm−1, which are polarized mostly along the c, b, and a crystal axes, respectively. By combining the optical and the paramagnetic resonance results, the one-electron orbital sequence was found to be dz2>dx2-y2>dyz>dxy>dxz. For a possible site of copper incorporation an interstitial position was chosen which has approximately D2 symmetry.