scholarly journals Self-association of an indole based guanidinium-carboxylate-zwitterion: formation of stable dimers in solution and the solid state

2010 ◽  
Vol 6 ◽  
Author(s):  
Carolin Rether ◽  
Wilhelm Sicking ◽  
Roland Boese ◽  
Carsten Schmuck
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Binding Sites ◽  
Ion Pairs ◽  
Ph Titration ◽  
X Ray ◽  
Ideal Orientation ◽  
Guanidinium Group ◽  
Self Association ◽  
Zwitterion Formation

The indole based zwitterion 2 forms stable dimers held together by H-bond assisted ion pairs. Dimerisation was confirmed in the solid state and studied in solution using dilution NMR experiments. Even though zwitterion 2 forms very stable dimers even in DMSO, their stability is lower than of an analogous pyrrole based zwitterion 1. As revealed by the X-ray crystal structure the two binding sites in 2 cannot be planar due to steric interactions between the guanidinium group and a neighbouring aromatic CH. Hence the guanidinium moiety is twisted out of planarity from the rest of the molecule forcing the two monomers in dimer 2·2 to interact in a non-ideal orientation. Furthermore, the acidity of the NHs is lower than in 1 (as determined by UV-pH-titration) also leading to less efficient binding interactions.

X-ray Crystal Structure of Gallium Tris- (8-hydroxyquinoline):  Intermolecular π−π Stacking Interactions in the Solid State

1999 ◽  
Vol 11 (3) ◽  
pp. 530-532 ◽  
Author(s):  
Yue Wang ◽  
Weixing Zhang ◽  
Yanqin Li ◽  
Ling Ye ◽  
Guangdi Yang
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Stacking Interactions ◽  
X Ray ◽  
Π Stacking

A MOF based on a lead(II) 2-oxido-6-methylpyridine-4-carboxylate network

2020 ◽  
Vol 75 (4) ◽  
pp. 365-369
Author(s):  
Long Tang ◽  
Yu Pei Fu ◽  
Na Cui ◽  
Ji Jiang Wang ◽  
Xiang Yang Hou ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Carboxylic Acid ◽  
Thermogravimetric Analysis ◽  
Metal Organic Framework ◽  
X Ray Diffraction ◽  
X Ray ◽  
Connected Node ◽  
Metal Organic ◽  
Solid State Fluorescence

AbstractA new metal-organic framework, [Pb(hmpcaH)2]n (1), has been hydrothermally synthesized from Pb(OAc)2 · 3H2O and 2-hydroxy-6-methylpyridine-4-carboxylic acid (hmpcaH2; 2), and characterized by IR spectroscopy, elemental and thermogravimetric analysis, and single-crystal X-ray diffraction. In complex 1, each hmpcaH− ligand represents a three-connected node to combine with the hexacoordinated Pb(II) ions, generating a 3D binodal (3,6)-connected ant network. The crystal structure of 2 was determined. The solid-state fluorescence properties of 1 and 2 were investigated.

scholarly journals Investigation of Solvatomorphism and Its Photophysical Implications for Archetypal Trinuclear Au3(1-Methylimidazolate)3

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4404
Author(s):  
Shengyang Guan ◽  
David C. Mayer ◽  
Christian Jandl ◽  
Sebastian J. Weishäupl ◽  
Angela Casini ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Density Functional ◽  
Bulk Material ◽  
Variable Temperature ◽  
Active Phase ◽  
Solvent Free ◽  
X Ray Diffraction ◽  
X Ray ◽  
Aurophilic Interactions

A new solvatomorph of [Au3(1-Methylimidazolate)3] (Au3(MeIm)3)—the simplest congener of imidazolate-based Au(I) cyclic trinuclear complexes (CTCs)—has been identified and structurally characterized. Single-crystal X-ray diffraction revealed a dichloromethane solvate exhibiting remarkably short intermolecular Au⋯Au distances (3.2190(7) Å). This goes along with a dimer formation in the solid state, which is not observed in a previously reported solvent-free crystal structure. Hirshfeld analysis, in combination with density functional theory (DFT) calculations, indicates that the dimerization is generally driven by attractive aurophilic interactions, which are commonly associated with the luminescence properties of CTCs. Since Au3(MeIm)3 has previously been reported to be emissive in the solid-state, we conducted a thorough photophysical study combined with phase analysis by means of powder X-ray diffraction (PXRD), to correctly attribute the photophysically active phase of the bulk material. Interestingly, all investigated powder samples accessed via different preparation methods can be assigned to the pristine solvent-free crystal structure, showing no aurophilic interactions. Finally, the observed strong thermochromism of the solid-state material was investigated by means of variable-temperature PXRD, ruling out a significant phase transition being responsible for the drastic change of the emission properties (hypsochromic shift from 710 nm to 510 nm) when lowering the temperature down to 77 K.

Solid state stereochemistry of crown ethers: X-ray crystal structure and 13C NMR studies of the LiNCS complex of 1,4,7,11-tetraoxacyclotetradecane

2000 ◽  
Vol 78 (3) ◽  
pp. 316-321
Author(s):  
G W Buchanan ◽  
A B Driega ◽  
G PA Yap
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Crown Ether ◽  
13C Nmr ◽  
Title Complex ◽  
Nmr Studies ◽  
Nmr Spectrum ◽  
X Ray ◽  
Large Amplitude Motion ◽  
C Nmr

The title complex is asymmetric in the crystal due to the spatial orientation of the NCS function. The space group has been determined to be P21 with a = 9.496(3), b = 8.736(3), c = 9.676(3) Å, β = 117.859(5)°, and Z = 2. The solid state 13C NMR spectrum is consistent with the lack of symmetry in the crystal and there is little evidence for large amplitude motion in the macrocycle as determined from the dipolar dephased spectrum.Key words: macrocyclic crown ether, lithium complex.

scholarly journals Crystal structure and tautomerism of Pigment Yellow 138 determined by X-ray powder diffraction and solid-state NMR

2016 ◽  
Vol 131 ◽  
pp. 364-372 ◽  
Author(s):  
Silke D. Gumbert ◽  
Meike Körbitzer ◽  
Edith Alig ◽  
Martin U. Schmidt ◽  
Michele R. Chierotti ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Powder Diffraction ◽  
Solid State Nmr ◽  
X Ray

scholarly journals Incensfuran: isolation, X-ray crystal structure and absolute configuration by means of chiroptical studies in solution and solid state

RSC Advances ◽  
2017 ◽  
Vol 7 (67) ◽  
pp. 42357-42362 ◽  
Author(s):  
Najeeb Ur Rehman ◽  
Hidayat Hussain ◽  
Sulaiman Al-Shidhani ◽  
Satya Kumar Avula ◽  
Ghulam Abbas ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Absolute Configuration ◽  
X Ray ◽  
Crude Extracts ◽  
Boswellia Papyrifera

A new cembrane diterpene named incensfuran (1), biogenetically derived from incensole (2), was isolated from crude extracts of the Boswellia papyrifera Hochst.

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