scholarly journals Charge transfer complexation of N,N-dimethyl-p-toluidine with nitrogen heteroaromatic cations as a model for association complexes in hydride transfer reactions

1988 ◽  
Vol 66 (10) ◽  
pp. 2532-2539 ◽  
Author(s):  
John W. Bunting ◽  
Mark A. Luscher
Keyword(s):  
Charge Transfer ◽  
Reaction Pathway ◽  
Hydride Transfer ◽  
Transfer Reactions ◽  
Acetonitrile Solution ◽  
Extinction Coefficients ◽  
Wavelength Absorption ◽  
Pyridinium Cations ◽  
Charge Transfer Complexation ◽  
Donor Species

Charge-transfer complexation of N,N-dimethyl-p-toluidine (DMT) with each of the following N-methyl cations has been investigated in acetonitrile solution at 25 °C: acridinium; phenanthridinium; 3-X-quinolinium and 4-X-isoquinolinium (X = H, Br, CONH2, CN); 5-nitroisoquinolinium; 3-X-pyridinium (X = CONH2, CN) (also the N-benzyl pyridinium cations); N,N′-dimethyl-4,4′-dipyridylium dication. Charge-transfer absorption maxima are reported, and extinction coefficients (εmax) at these maxima and association constants (K) for 1:1 complex formation have been evaluated from the dependence of absorbance upon [DMT]. In general, the longest wavelength absorption maximum increases with increasing association constant. There is a strictly linear relationship between εmax and 1/K. These observations are considered in the context of theories of charge-transfer spectra. Such charge-transfer species are considered as models for the association complexes that are believed to exist upon the reaction pathway for hydride transfer between heteroaromatic cations. Although some significant qualitative relationships are apparent, variations in susceptibility of heteroaromatic cations to charge-transfer complexation are much smaller than variations in the reactivity of these cations towards hydride donor species.

Hydride transfer reactions. Oxidation of N-methylacridan by π acceptors

1977 ◽  
Vol 55 (14) ◽  
pp. 2741-2751 ◽  
Author(s):  
Allan K. Colter ◽  
Gunzi Saito ◽  
Frances J. Sharom
Keyword(s):  
Charge Transfer ◽  
Isotope Effect ◽  
Isotopic Exchange ◽  
Hydride Transfer ◽  
Transfer Reactions ◽  
Kinetic Measurements ◽  
Rate Of Reaction ◽  
Hydride Transfer Reactions ◽  
Isotope Partitioning

The oxidation of N-methylacridan (1) to N-methylacridinium ion (2) by the π acceptors p-benzoquinone (BQ), 7,7,8,8-tetracyanoquinodimethane (TCNQ), p-chloranil (CA), tetracyanoethylene (TCNE), and 2,3-dicyano-1,4-benzoquinone (DCBQ) has been investigated. Second-order rate constants in acetonitrile (AN) vary by a factor of more than 107 for this series. The rate of reaction of 1 with BQ increases 45-fold as the solvent composition is varied from AN to 50% (v/v) AN–water, but is insensitive to changes in buffer ratio or concentration in 75% AN. Spectroscopic evidence for charge-transfer complexing between the reactants was obtained with BQ and CA, and kinetic evidence for complexing was obtained with BQ in 75% AN. The primary isotope effect, p, calculated from the rates of oxidation of 1, 1-9-d, and 1-9,9-d2 (1(HH), 1(HD), and 1(DD)) in AN varied from 4.5 (TCNE) to 13 (BQ), while the secondary isotope effect, s, was approximately constant (∼1.1). Values of the isotope partitioning ratio, ipr (the ratio of 2(D) to 2(H) formed in reaction of 1(HD)) were determined for BQ in three AN-water mixtures and for CA, TCNE, and DCBQ in AN. For all systems studied, except BQ in 90% AN, where determination of the ipr is complicated by isotopic exchange between unreacted 1 and product (2), the ipr agrees with p/s from the kinetic measurements. These results are discussed in terms of mechanism and compared with those of other hydride transfer reactions involving dihydronicotinamide donors.

scholarly journals A Methodology to Discriminate Between Hydroxyl Radical-induced Processes and Direct Charge-transfer Reactions in Heterogeneous Photocatalysis

2016 ◽  
Vol 19 (2) ◽  
Author(s):  
Stefano Bertinetti ◽  
Marco Minella ◽  
Francesco Barsotti ◽  
Valter Maurino ◽  
Claudio Minero ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Charge Transfer ◽  
Hydroxyl Radicals ◽  
Reaction Pathway ◽  
Phenol Degradation ◽  
Heterogeneous Photocatalysis ◽  
Transfer Reactions ◽  
Hydroxybenzoic Acid ◽  
Transfer Processes ◽  
Charge Transfer Reactions

AbstractA method to assess the ability of a photocatalyst to induce reactions with free or trapped hydroxyl radicals versus direct charge-transfer processes is here proposed, based on the use of phenol and 2-hydroxybenzoic acid (salicylic acid) as test substrates. The rationale is that phenol degradation would be preferentially (although not exclusively) induced by hydroxyl radicals, while salicylic acid would mainly undergo direct charge-transfer oxidation. The use of t-butanol as selective ·OH scavenger is helpful to understand how much each substrate is a selective indicator of the intended reaction pathway in the presence of a given semiconductor oxide. Phenol and salicylic acid should be used at low concentration (e.g. 25 μmol L

scholarly journals Molecular Modeling of the Reaction Pathway and Hydride Transfer Reactions of HMG-CoA Reductase

Biochemistry ◽  
2012 ◽  
Vol 51 (40) ◽  
pp. 7983-7995 ◽  
Author(s):  
Brandon E. Haines ◽  
C. Nicklaus Steussy ◽  
Cynthia V. Stauffacher ◽  
Olaf Wiest
Keyword(s):  
Molecular Modeling ◽  
Reaction Pathway ◽  
Hydride Transfer ◽  
Transfer Reactions ◽  
Hmg Coa Reductase ◽  
Hydride Transfer Reactions ◽  
Coa Reductase

scholarly journals Freeze the dynamicity: charge transfer complexation assisted control over the reaction pathway

2019 ◽  
Vol 10 (43) ◽  
pp. 10035-10039 ◽  
Author(s):  
Nilotpal Singha ◽  
Basab Kanti Das ◽  
Bapan Pramanik ◽  
Saurav Das ◽  
Debapratim Das
Keyword(s):  
Charge Transfer ◽  
Solid State ◽  
Reaction Pathway ◽  
Thiol Groups ◽  
Donor And Acceptor ◽  
Charge Transfer Complexation ◽  
Ct Complexes ◽  
Acceptor Molecules

Aqueous CT complexes of donor and acceptor molecules with reactive thiol groups were frozen and lyophilized to get alternate D–A assemblies in the solid state. Oxidation of the thiols resulted in asymmetric disulfides exclusively.

Charge Transfer Complexation Boosts Molecular Conductance Through Fermi Level Pinning

2018 ◽  
Author(s):  
Kun Wang ◽  
Andrea Vezzoli ◽  
Iain Grace ◽  
Maeve McLaughlin ◽  
Richard Nichols ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Single Molecule ◽  
Quantum Interference ◽  
Transmission Function ◽  
Scanning Tunneling ◽  
Charge Transfer Complexes ◽  
Tunneling Microscopy ◽  
Quantum Interference Effect ◽  
Single Molecule Junctions ◽  
Charge Transfer Complexation

We have used scanning tunneling microscopy to create and study single molecule junctions with thioether-terminated oligothiophene molecules. We find that the conductance of these junctions increases upon formation of charge transfer complexes of the molecules with tetracyanoethene, and that the extent of the conductance increase is greater the longer is the oligothiophene, i.e. the lower is the conductance of the uncomplexed molecule in the junction. We use non-equilibrium Green's function transport calculations to explore the reasons for this theoretically, and find that new resonances appear in the transmission function, pinned close to the Fermi energy of the contacts, as a consequence of the charge transfer interaction. This is an example of a room temperature quantum interference effect, which in this case boosts junction conductance in contrast to earlier observations of QI that result in diminished conductance.<br>

Dioxastilbenophanes—synthesis and charge transfer complexation studies

Tetrahedron ◽  
2004 ◽  
Vol 60 (10) ◽  
pp. 2351-2360 ◽  
Author(s):  
Perumal Rajakumar ◽  
Venghatraghavan Murali
Keyword(s):  
Charge Transfer ◽  
Complexation Studies ◽  
Charge Transfer Complexation

Charge Transfer Reactions in CO 2 Electroreduction on Manganese Doped Ceria

2019 ◽  
Vol 6 (6) ◽  
pp. 1668-1672 ◽  
Author(s):  
Zhidong Huang ◽  
Lei Shang ◽  
Huiying Qi ◽  
Zhe Zhao ◽  
Baofeng Tu ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Transfer Reactions ◽  
Doped Ceria ◽  
Charge Transfer Reactions

scholarly journals Charge Transfer Reactions in Lithium-ion Batteries

Hyomen Kagaku ◽  
2006 ◽  
Vol 27 (10) ◽  
pp. 609-612 ◽  
Author(s):  
Takeshi ABE ◽  
Zempachi OGUMI
Keyword(s):  
Charge Transfer ◽  
Lithium Ion Batteries ◽  
Lithium Ion ◽  
Transfer Reactions ◽  
Charge Transfer Reactions
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