Possibilities of organic ferromagnets and ferrimagnets by the use of charge-transfer (CT) complexes with radical substituents. Ab initio MO studies

Conformation of nicotinamide (I), 3-carbamoylpyridinium (IIa), 1-methyl-3-carbamoylpyridinium (IIb), and 1-methyl-1,4-dihydronicotinamide (IIIa) has been studied in the rigid rotor approximation on the basis of non-empirical STO-3G wave functions. The rotation barriers decrease in the order: IIIa > I ~ IIb > IIa. When confronted with semiempirical calculations, the conformation curves of molecular energy show a better qualitative similarity to the EHT than to NDDO and particularly to CNDO/2 curves. Relation of the calculated characteristics to experimental findings is discussed.

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Charge Transfer Complexes of Ketotifen with 2,3-Dichloro-5,6-dicyano-p-benzoquinone and 7,7,8,8-Tetracyanoquodimethane: Spectroscopic Characterization Studies

Molecules ◽

10.3390/molecules26072039 ◽

2021 ◽

Vol 26 (7) ◽

pp. 2039

Author(s):

Gamal A. E. Mostafa ◽

Ahmed Bakheit ◽

Najla AlMasoud ◽

Haitham AlRabiah

Keyword(s):

Charge Transfer ◽

Spectroscopic Characterization ◽

Molar Ratio ◽

Charge Transfer Complexes ◽

Physical Parameters ◽

Spectrophotometric Methods ◽

Theoretical Approaches ◽

The Stability ◽

Ct Complexes

The reactions of ketotifen fumarate (KT) with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and 7,7,8,8-tetracyanoquinodimethane (TCNQ) as π acceptors to form charge transfer (CT) complexes were evaluated in this study. Experimental and theoretical approaches, including density function theory (DFT), were used to obtain the comprehensive, reliable, and accurate structure elucidation of the developed CT complexes. The CT complexes (KT-DDQ and KT-TCNQ) were monitored at 485 and 843 nm, respectively, and the calibration curve ranged from 10 to 100 ppm for KT-DDQ and 2.5 to 40 ppm for KT-TCNQ. The spectrophotometric methods were validated for the determination of KT, and the stability of the CT complexes was assessed by studying the corresponding spectroscopic physical parameters. The molar ratio of KT:DDQ and KT:TCNQ was estimated at 1:1 using Job’s method, which was compatible with the results obtained using the Benesi–Hildebrand equation. Using these complexes, the quantitative determination of KT in its dosage form was successful.

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Structural Parameters and Internal Rotational Barriers of tert-Butylammonium Ion: AM1 and ab initio Calculations

Zeitschrift für Naturforschung A ◽

10.1515/zna-1992-1215 ◽

1992 ◽

Vol 47 (12) ◽

pp. 1255-1256

Author(s):

Hiroyuki Ishida ◽

Yoshihiro Kubozono ◽

Setsuo Kashino ◽

Ryuichi Ikeda

Keyword(s):

Ab Initio Calculations ◽

Ab Initio ◽

Internal Rotation ◽

Barrier Height ◽

Structural Parameters ◽

Mo Calculations ◽

Ab Initio Mo Calculations ◽

Rotational Barriers ◽

Ab Initio Mo ◽

Internal Rotational Barriers

Semiempirical and ab initio MO calculations were performed to estimate the structural parameters of tert-butylammonium ion and its potential energies for the internal rotation of the CH3 and NH3+ groups. The barrier height for the rotation of NH3+ was found to be lower than for that of CH3 , corresponding to the C - N bond being longer than the C - C bond.

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