Thiazetidin-2-ylidenes as Four Membered N-heterocyclic Carbenes: Theoretical Studies and the Generation of Complexes with N+ Center

2021 ◽  
Author(s):  
Gurudutt Dubey ◽  
Nutan Mahawar ◽  
Tejender Singh ◽  
Nirjhar Saha ◽  
Subash Chandra Sahoo ◽  
...  
Keyword(s):  
Quantum Chemical ◽  
Heterocyclic Carbenes ◽  
Theoretical Studies ◽  
Chemical Studies ◽  
Quantum Chemical Studies

Thiazetidin-2-ylidenes have been designed as four membered N-heterocyclic carbenes (NHCs) using quantum chemical studies. These species are smaller analogs of thiazol-2-ylidenes, possess high singlet stability (57 kcal/mol) and large nucleophilicity...

scholarly journals Experimental and quantum chemical studies of anionic analogues of N-heterocyclic carbenes

2018 ◽  
Vol 47 (22) ◽  
pp. 7445-7455 ◽  
Author(s):  
Haoyu Niu ◽  
Robert J. Mangan ◽  
Andrey V. Protchenko ◽  
Nicholas Phillips ◽  
Wiebke Unkrig ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Quantum Chemical ◽  
Heterocyclic Carbenes ◽  
Anionic Ligands ◽  
Chemical Studies ◽  
Quantum Chemical Studies

A combination of quantum chemical and synthetic/crystallographic methods have been employed to probe electronic structure in two series of anionic ligands related to the well-known NHC donor class.

scholarly journals Deeper insight into the properties of the newly synthesized macrocycles as drug receptors – some preliminary quantum chemical studies

2017 ◽  
Vol 41 (2) ◽  
pp. 521-529 ◽  
Author(s):  
Anna Ignaczak ◽  
Stanisław Porwański ◽  
Michalina Szyszka
Keyword(s):  
Quantum Chemical ◽  
Theoretical Studies ◽  
Chemical Studies ◽  
Quantum Chemical Studies ◽  
Drug Receptors ◽  
Experimental And Theoretical Studies ◽  
Insight Into

We present the results of our experimental and theoretical studies on 1,10-N,N′-bis-(β-d-ureidocellobiosyl)-4,7,13-trioxa-1,10-diazacyclopentadecane, its complex with aspirin and the corresponding host–guest interactions.

Quantum Chemical Studies of Hole Transfer in Liquid Hexane

2017 ◽  
Vol 137 (7) ◽  
pp. 435-441
Author(s):  
Masahiro Sato ◽  
Akiko Kumada ◽  
Kunihiko Hidaka ◽  
Toshiyuki Hirano ◽  
Fumitoshi Sato
Keyword(s):  
Quantum Chemical ◽  
Hole Transfer ◽  
Chemical Studies ◽  
Quantum Chemical Studies

ESR, spectroscopic, and quantum-chemical studies on the electronic structures of complexes formed by Cu(I) with radicals

1986 ◽  
Vol 22 (1) ◽  
pp. 27-33
Author(s):  
N. P. Gritsan ◽  
O. M. Usov ◽  
N. V. Shokhirev ◽  
I. V. Khmelinskii ◽  
V. F. Plyusnin ◽  
...  
Keyword(s):  
Electronic Structures ◽  
Quantum Chemical ◽  
Chemical Studies ◽  
Quantum Chemical Studies

scholarly journals Quantum-Chemical Search for Keto Tautomers of Azulenols in Vacuo and Aqueous Solution

Symmetry ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 497
Author(s):  
Ewa D. Raczyńska
Keyword(s):  
Aqueous Solution ◽  
Quantum Chemical ◽  
Biologically Active ◽  
Deprotonation Reaction ◽  
Chemical Studies ◽  
Quantum Chemical Studies ◽  
Scanty Information ◽  
Derivatives Of ◽  
Common Anion ◽  
Tautomeric Mixture

Keto-enol prototropic conversions for carbonyl compounds and phenols have been extensively studied, and many interesting review articles and even books appeared in the last 50 years. Quite a different situation takes place for derivatives of biologically active azulene, for which only scanty information on this phenomenon can be found in the literature. In this work, quantum-chemical studies have been undertaken for symmetrically and unsymmetrically substituted azulenols (constitutional isomers of naphthols). Stabilities of two enol (OH) rotamers and all possible keto (CH) tautomers have been analyzed in the gas phase {DFT(B3LYP)/6-311+G(d,p)} and also in aqueous solution {PCM(water)//DFT(B3LYP)/6-311+G(d,p)}. Contrary to naphthols, for which the keto forms can be neglected, at least one keto isomer (C1H, C2H, and/or C3H) contributes significantly to the tautomeric mixture of each azulenol to a higher degree in vacuo (non-polar environment) than in water (polar amphoteric solvent). The highest amounts of the CH forms have been found for 2- and 5-hydroxyazulenes, and the smallest ones for 1- and 6-hydroxy derivatives. The keto tautomer(s), together with the enol rotamers, can also participate in deprotonation reaction leading to a common anion and influence its acid-base properties. The strongest acidity in vacuo exhibits 6-hydroxyazulene, and the weakest one displays 1-hydroxyazulene, but all azulenols are stronger acids than phenol and naphthols. Bond length alternation in all DFT-optimized structures has been measured using the harmonic oscillator model of electron delocalization (HOMED) index. Generally, the HOMED values decrease for the keto tautomers, particularly for the ring containing the labile proton. Even for the keto tautomers possessing energetic parameters close to those of the enol isomers, the HOMED indices are low. However, some kind of parallelism exists for the keto forms between their relative energies and HOMEDs estimated for the entire molecules.

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