Similarity Searching in Files of Three-Dimensional Chemical Structures. Alignment of Molecular Electrostatic Potential Fields with a Genetic Algorithm

1996 ◽  
Vol 36 (2) ◽  
pp. 159-167 ◽  
Author(s):  
David J. Wild ◽  
Peter Willett
2019 ◽  
Vol 75 (11) ◽  
pp. 1582-1585 ◽  
Author(s):  
Adnan M. Qadir ◽  
Sevgi Kansiz ◽  
Necmi Dege ◽  
Georgina M. Rosair ◽  
Igor O. Fritsky

In the title compound, bis(2-methoxyethyl xanthato-κS)(N,N,N′,N′-tetramethylethylenediamine-κ2 N,N′)zinc(II) acetone hemisolvate, [Zn(C4H7O2S2)2(C6H16N2)]·0.5C3H6O, the ZnII ion is coordinated by two N atoms of the N,N,N′,N′-tetramethylethylenediamine ligand and two S atoms from two 2-methoxyethyl xanthate ligands. The amine ligand is disordered over two orientations and was modelled with refined occupancies of 0.538 (6) and 0.462 (6). The molecular structure features two C—H...O and two C—H...S intramolecular interactions. In the crystal, molecules are linked by weak C—H...O and C—H...S hydrogen bonds, forming a three-dimensional supramolecular architecture. The molecular structure was optimized using density functional theory (DFT) at the B3LYP/6–311 G(d,p) level. The smallest HOMO–LUMO energy gap (3.19 eV) indicates the suitability of this crystal for optoelectronic applications. The molecular electrostatic potential (MEP) further identifies the positive, negative and neutral electrostatic potential regions of the molecules. Half a molecule of disordered acetone was removed with the solvent-mask procedure in OLEX2 [Dolomanov et al. (2009). J. Appl. Cryst. 42, 339–341] and this contribition is included in the formula.


2017 ◽  
Vol 232 (5) ◽  
pp. 385-394 ◽  
Author(s):  
Paramita Chatterjee ◽  
Tanusri Dey ◽  
Sarbani Pal ◽  
Alok K. Mukherjee

AbstractTwo mefenamic acid (1) derivatives, prop-2-ynyl 2-(2,3-dimethylphynylamino)benzoate (2) and N′-(dihydro-2H-pyran-4(3H)-ylidene)-2-((2,3-dimethylphenyl)amino)benzohydrazide (3), have been synthesized and their crystal structures have been determined from laboratory powder X-ray diffraction data. The DFT optimized molecular geometry in 2 and 3 agrees closely to that obtained from the crystallographic study. The nature of intermolecular interactions in 2 and 3 has been analyzed through Hirshfeld surfaces and two-dimensional fingerprint plots, and compared with that in the mefenamic acid polymorphs. Intermolecular N–H···N, C–H···O/N and C–H···π(arene) interactions in 2 and 3 assemble molecules into two and three-dimensional supramolecular frameworks, respectively. Hydrogen-bond based interactions in 2 and 3 have been complimented by calculating molecular electrostatic potential surfaces. Hirshfeld surface analyses of 2, 3, three mefenamic acid polymorphs and a few related mefenamic acid derivatives retrieved from the Cambridge Structural Database (CSD) indicate that about 80% of the Hirshfeld surface areas in these compounds are due to H···H and C···H/H···C contacts.


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