Halogenated (F, Cl, Br, or I) Diphenylhexatrienes: Crystal Structures, Fluorescence Spectroscopic Properties, and Quantum Chemical Calculations

2016 ◽  
Vol 16 (7) ◽  
pp. 4060-4071 ◽  
Author(s):  
Yoriko Sonoda ◽  
Midori Goto ◽  
Yuki Matsumoto ◽  
Yukihiro Shimoi ◽  
Fumio Sasaki ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Spectroscopic Properties

Cyclisierung von Di(tert-butyl-methyl)ketazin zu 1,2-Diaza-3-bora- und 1,2-Diaza-3-sila-cyclopent-5-enen / Cyclization of Di(tert-butyl-methyl)ketazine to 1,2-Diaza-3-bora- and 1,2-Diaza-3-sila-cyclopent-5-enes

2006 ◽  
Vol 61 (10) ◽  
pp. 1261-1274 ◽  
Author(s):  
Florian Armbruster ◽  
Nina Armbruster ◽  
Uwe Klingebiel ◽  
Mathias Noltemeyer ◽  
Stefan Schmatz
Keyword(s):  
Crystal Structures ◽  
Quantum Chemical Calculations ◽  
Chlorine Atom ◽  
Quantum Chemical ◽  
Membered Ring ◽  
Substitution Product ◽  
Tert Butyl ◽  
Isomeric Structures

The results of quantum chemical calculations on lithium ketazides suggest mainly four isomeric structures with different modes of lithium coordination (A-D). A monolithium ketazide thf-adduct (1) was isolated supporting the results of the quantum chemical calculations. In reactions of the lithiated di(tert-butyl-methyl)ketazine with BCl3 and Cl2BPh, 1,2-aza-azonia-3-borata-cyclopent-5-enes (2, 3) were isolated. Substitution of a chlorine atom of 2 and 3 with t-BuLi leads to the formation of derivatives 4 and 5. HCl elimination from 2 with Et3N gives - via a diazaboracyclopentene (6) - a bicyclus 7. In the reaction of the dilithiated ketazine with F2BN(SiMe3)2, the diaza-boracyclopentene 8 is obtained while with Cl4Si, F3SiN(SiMe3)2, and Cl2SiMe2 the diazasilacyclopentenes 9 - 11 are generated. SiF4 reacts with the dilithium ketazide to give a spirocyclus (12). The monolithium ketazide and Cl2SiMe2 react at 30 °C to give a four-membered ring isomer of the substitution product which is formed via a 1,3-chlorine shift from silicon to carbon (13). A tetrameric silanolate was isolated as a by-product in this reaction. It gives evidence for the structure of lithium ketazide A. Crystal structures of 5, 7, 10, and 14 are reported.

Halogen bonds as a tool in the design of high energetic materials: evidence from crystal structures and quantum chemical calculations

CrystEngComm ◽  
2021 ◽  
Author(s):  
Aleksandra B. Đunović ◽  
Dušan Ž Veljković
Keyword(s):  
Crystal Structures ◽  
Quantum Chemical Calculations ◽  
Electrostatic Potential ◽  
Energetic Materials ◽  
Quantum Chemical ◽  
Central Area ◽  
Molecular Surface ◽  
Halogen Bonds ◽  
Positive Electrostatic Potential

Positive electrostatic potential over the central area of the molecular surface is one of the main characteristics of high energetic materials (HEM) that determines their sensitivity towards detonation. The influence...

Stacking interactions of resonance-assisted hydrogen-bridged rings and C6-aromatic rings

2020 ◽  
Vol 22 (24) ◽  
pp. 13721-13728 ◽  
Author(s):  
Jelena P. Blagojević Filipović ◽  
Michael B. Hall ◽  
Snežana D. Zarić
Keyword(s):  
Crystal Structures ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Cambridge Structural Database ◽  
Stacking Interactions ◽  
Aromatic Rings ◽  
Structural Database

Stacking interactions between six-membered resonance-assisted hydrogen-bridged (RAHB) rings and C6-aromatic rings have been studied by analyzing crystal structures in the Cambridge Structural Database and performing quantum chemical calculations.

C,C- and N,C-Coupled Dimers of 2-Aminotetraphenylporphyrins: Regiocontrolled Synthesis, Spectroscopic Properties, and Quantum-Chemical Calculations

2014 ◽  
Vol 20 (14) ◽  
pp. 3998-4006 ◽  
Author(s):  
Torsten Bruhn ◽  
Franziska Witterauf ◽  
Daniel C. G. Götz ◽  
Carina T. Grimmer ◽  
Max Würtemberger ◽  
...  
Keyword(s):  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Spectroscopic Properties ◽  
C And N ◽  
Regiocontrolled Synthesis

Influence of ortho-substituent on the molecular and crystal structures of 2-(N-arylimino)coumarin-3-carboxamide: isotypic and polymorphic structures

2019 ◽  
Vol 75 (5) ◽  
pp. 887-902 ◽  
Author(s):  
Svitlana V. Shishkina ◽  
Irina S. Konovalova ◽  
Sergiy M. Kovalenko ◽  
Pavlo V. Trostianko ◽  
Anna O. Geleverya ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Polymorphic Modification ◽  
Aryl Group ◽  
Group Iii ◽  
Pairwise Interactions ◽  
Group I ◽  
Polymorphic Modifications ◽  
Molecular And Crystal Structures

During a comprehensive study of a series of 2-(N-arylimino)coumarin-3-carboxamides with the aryl group substituted in the ortho-position by either a halogen atom, a methyl group or a methoxy group, the existence of three groups of isotypic crystal structures has been revealed. The similarity of crystal structures belonging to the same groups was confirmed by the analysis based on the comparison of pairwise interactions energies obtained from quantum chemical calculations. Group I includes unsubstituted, methyl-substituted and polymorphic modification 1 of fluoro-substituted 2-(N-arylimino)coumarin-3-carboxamide. Structures of polymorphic modification 2 of fluoro-substituted derivative, chloro-substituted and polymorphic modification 1 of bromo-substituted 2-(N-arylimino)coumarin-3-carboxamide may represent group II. Group III contains structures of polymorphic modification 2 of bromo-substituted derivative, iodine- and methoxy-substituted 2-(N-arylimino)coumarin-3-carboxamides. Structures of the same type group have extremely close parameters of the unit cell as well as those of molecular and crystal structures. But they are not identical. Polymorphic modifications of fluoro- and bromo-substituted 2-(N-arylimino)coumarin-3-carboxamides belong to different crystal types mainly due to different arrangement of basic structural motifs separated out using quantum chemical calculations.

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