Abstract:The title peptide, C7H14N2O3, crystallizes with seven independent molecules in the asymmetric unit. All have essentially the same overall conformation, but some flexibility is exhibited by the glycine residue. It appears that the high Z' value, observed only three times before for an organic compound, permits formation of shorter hydrogen bonds in one of the two head-to-tail chains involving the N-terminal amino groups and the C-terminal carboxylate groups than found in a hypothetical model structure of glycyl… Show more
“…The lattice parameters are evaluated for GLV as a = 5.5238(7)Å, b = 26.581(3)Å and c = 44.093(5)Å with space group P2 1 2 1 2 1 . The calculated lattice parameters from the PXRD are in good agreement with the reported values [13].Fig. 2(a) PXRD (b) SCXRD data of the GLV generated (Ref.…”
Section: Resultssupporting
confidence: 86%
“…The crystal structure of glycyl-L-Valine (GLV) crystal was reported by C. H. Gorbitz et.al. [13]. Based on these information, steps have been taken to grow glycyl-L-Valine (GLV) single crystal by slow evaporation method.…”
Glycyl-L-Valine (GLV) crystals were grown using distilled water as the solvent at room temperature by solution growth technique. Powder X-ray diffraction confirms the crystalline quality of GLV crystal. The molecular structure of GLV crystal was identified by
13
C NMR spectral studies. The nonlinear optical (NLO) behavior of the crystal was found to be ∼4.3 times greater than that of potassium dihydrogen orthophosphate. FT-Raman and FT-IR spectra of the GLV were recorded and complete functional group assignment of the determined vibrational bands of GLV have been reported. Density functional theoretical method (DFT) was performed using B3LYP with the 6-311+G (d, p) basis set and the results were compared with the experimental values which confirm the intermolecular interactions responsible for the enhanced NLO activity of the molecule, as evident from NBO and Hirshfeld analyses. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. In addition, the molecular electrostatic potential (MEP) analysis, Mulliken atomic charges of the GLV molecule has been investigated using theoretical calculations.
“…The lattice parameters are evaluated for GLV as a = 5.5238(7)Å, b = 26.581(3)Å and c = 44.093(5)Å with space group P2 1 2 1 2 1 . The calculated lattice parameters from the PXRD are in good agreement with the reported values [13].Fig. 2(a) PXRD (b) SCXRD data of the GLV generated (Ref.…”
Section: Resultssupporting
confidence: 86%
“…The crystal structure of glycyl-L-Valine (GLV) crystal was reported by C. H. Gorbitz et.al. [13]. Based on these information, steps have been taken to grow glycyl-L-Valine (GLV) single crystal by slow evaporation method.…”
Glycyl-L-Valine (GLV) crystals were grown using distilled water as the solvent at room temperature by solution growth technique. Powder X-ray diffraction confirms the crystalline quality of GLV crystal. The molecular structure of GLV crystal was identified by
13
C NMR spectral studies. The nonlinear optical (NLO) behavior of the crystal was found to be ∼4.3 times greater than that of potassium dihydrogen orthophosphate. FT-Raman and FT-IR spectra of the GLV were recorded and complete functional group assignment of the determined vibrational bands of GLV have been reported. Density functional theoretical method (DFT) was performed using B3LYP with the 6-311+G (d, p) basis set and the results were compared with the experimental values which confirm the intermolecular interactions responsible for the enhanced NLO activity of the molecule, as evident from NBO and Hirshfeld analyses. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. In addition, the molecular electrostatic potential (MEP) analysis, Mulliken atomic charges of the GLV molecule has been investigated using theoretical calculations.
“…15 Some explanatory references focusing on organic molecular crystals, in particular, have been given by Schonleber 13,16,17 and by Pinheiro and Abakumov. 18 Here we report on the known Z′ = 7 (WEVWOK) 19 and a newly discovered Z′ = 1 high-temperature phase of glycyl-Lvaline (Gly-L-Val). The latter phase is a nonmodulated version of the former.…”
Section: ■ Introductionmentioning
confidence: 92%
“…Here we report on the known Z ′ = 7 (WEVWOK) and a newly discovered Z ′ = 1 high-temperature phase of glycyl- l -valine (Gly- l -Val). The latter phase is a nonmodulated version of the former.…”
The high-Z′ (Z′
= 7) structure of glycyl-l-valine has been redetermined at
298 K, using synchrotron radiation and exploiting the superspace
approach. The analysis of the diffraction data reveals that the structure
can be described as a commensurately modulated crystal structure with
superspace group P212121(0σ20)000 and modulation wave vector q = (0, 2/7, 0). A new Z′ = 1 phase
has been discovered for this compound at 323 K that is related
to the known Z′ = 7 phase. The origin of the
modulated phase has been explored by analyzing intermolecular interactions
and molecular conformations in terms of t-plots and
through a comparison to (1) the newly discovered high-temperature
phase, (2) a hypothetical Z′ = 1 structure
at 298 K, and (3) a similar Z′ = 1
structure of the related compound glycyl-l-leucine. The results
show that the conformational flexibility of the glycyl-l-valine
molecule ensures optimization of the hydrogen-bond network which causes
the modulation and thus a high Z′ value of
the supercell. This study highlights the elegance and convenience
of the superspace approach to explain the occurrence of at least part
of the rarely occurring high-Z′ structures
of molecular compounds.
“…X-ray crystallographic analysis , (Figure ) revealed that the asymmetric unit of the crystal contains seven crystallographically independent molecules whose structures are essentially similar to each other. While a number of crystals containing several crystallographically independent molecules in the asymmetric unit have been reported, the ones containing seven are quite rare . Each molecule of [L 2 Pd 2 ] has two square-planar metal moieties lying almost parallel to one another at a distance of 3.4 Å (Figure a).…”
Unique helix of helix structures were formed via intermolecular π-stacking and metal-metal interactions in the crystal of single-helical dinuclear complexes [L(2)M(2)] (M = Pd, Ni) having an acyclic bis(N(2)O(2))-type ligand. The difference in the helical winding angle of the constituents (401.7° for [L(2)Pd(2)]; 421.3° for [L(2)Ni(2)]) led to variation of the helical pitches of the helical array (7(2) helix for [L(2)Pd(2)]; 6(2) helix for [L(2)Ni(2)]).
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