Relaxation Spectra and Association Constants of 1:1 Charge‐Transfer Complexes

1968 ◽  
Vol 49 (7) ◽  
pp. 3273-3286 ◽  
Author(s):  
H. J. G. Hayman
Keyword(s):  
Charge Transfer ◽  
Association Constants ◽  
Charge Transfer Complexes ◽  
Relaxation Spectra

Chemical behavior of charge-transfer complexes. VII. Solvolysis of alkyl arenesulfonate donors in the presence of aromatic acceptors

1978 ◽  
Vol 56 (4) ◽  
pp. 585-590 ◽  
Author(s):  
Allan K. Colter ◽  
Robert E. C. Turkos
Keyword(s):  
Acetic Acid ◽  
Charge Transfer ◽  
Kinetic Data ◽  
Association Constants ◽  
Charge Transfer Complexes ◽  
Chemical Behavior ◽  
Measurable Rate ◽  
Leaving Groups

Rates of solvolysis of several ethyl and 2-propyl arenesulfonates having π donor leaving groups were measured in the absence of accepter and in the presence of the π acceptors 1,3,5-trinitrobenzene (TNB) and 2,4,7-trinitrofluorenone (TNF). With four of the nine combinations investigated, added accepter produced small but measurable rate enhancements. Ester–TNF 1:1 association constants were measured spectrophotometrically at 20, 30, and 40 °C in acetic acid for 2-propyl 4-methoxy-1-naphthalenesulfonate (3b), 4,8-dimethoxy-1-naphthalenesulfonate (4), 3,7-dimethyl-1-naphthalenesulfonate (5), and 1-pyrenesulfonate (6). From the equilibrium and kinetic data, the reactivity of the 1:1 ester–TNF complex relative to that of the uncomplexed ester (kc/ku) in acetolysis at 85.73 °C was estimated to be lessthan 4.2 and 1.4 for 3b and 4, respectively, 4.4 ± 2.0 for 5, and 2.8 ± 0.4 for 6. The value of kc/ku for 6 determined from analysis of the kinetic data alone is 2.7 ± 0.8.

Photochemical reactions of charge-transfer complexes. The irradiation of the charge-transfer complexes between 1,4-, 1,5-, and 2,3-dimethoxynaphthalenes and 1,2-dicyanoethylenes

1980 ◽  
Vol 58 (9) ◽  
pp. 918-927 ◽  
Author(s):  
P. C. Wong ◽  
D. R. Arnold
Keyword(s):  
Charge Transfer ◽  
Triplet State ◽  
Ion Pair ◽  
Photochemical Reactions ◽  
Association Constants ◽  
Charge Transfer Complexes ◽  
Polar Solvents ◽  
Photostationary State ◽  
Ct Complex ◽  
Ct Complexes

The first part of this paper describes the experimental search for a donor which would complex preferentially one of the isomers of 1,2-dicyanoethylene. This involved measuring the association constants (KcDA) of the charge-transfer (ct) complexes of several dimethoxynaphthalenes (DMN) with maleonitrile (MN) and fumaronitrile (FN). From the measured KcDA, we found that MN complexes more strongly than FN with 1,4- and 1,5-DMN but that FN complexes more strongly with 2,3-DMN than does MN. These results are explained in terms of more than one favourable geometry for the ct complexes, since the donors are relatively large compared to the acceptors.Irradiation of the ct complexes between 1,4-, 1,5-, or 2,3-DMN and 1,2-dicyanoethylene led to isomerization of the olefins. The photostationary state depends on the absorption spectra of the ct complexes formed between the donor and the isomeric olefins. From spectroscopic and photo-CIDNP studies, we find evidence that the isomerization in polar solvents takes place via the triplet state of the olefin. The triplet is formed from the radical ion pair resulting after excitation of the ct complex.

Charge transfer complexes of diquat and paraquat with halide anions

1987 ◽  
Vol 65 (10) ◽  
pp. 2425-2427 ◽  
Author(s):  
S. G. Bertolotti ◽  
J. J. Cosa ◽  
H. E. Gsponer ◽  
C. M. Previtali
Keyword(s):  
Charge Transfer ◽  
Charge Transfer Band ◽  
Association Constants ◽  
Charge Transfer Complexes ◽  
Ion Selective Electrodes ◽  
Halide Ions ◽  
Ultraviolet Spectrophotometry ◽  
A Charge ◽  
Difference Absorption ◽  
Absorption Measurements

The association of methylviologen, 1,1′-dimethyl-4,4′-bipyridynium (PQ2+), with halide and pseudo-halide ions was studied in water at 25 °C by ultraviolet spectrophotometry. A charge transfer band could be observed in the region around 300 nm. From difference absorption measurements the first association constant (K1,) was obtained as 1.7 (Cl−), 3.3 (Br−), 3.9 (I−), 0.7 (CN−), and 2.0(SCN−) M−1. Similar results were obtained for the dication, 6,7-dihydrodipyrido[1,2-a:2′,1′-c]pyrazinium (DQ2+), with first association constants 3.3 (Cl−), 4.1 (Br−) and 4.6 (I−) M−1. First and second (K2) association constants were also determined by a potentiometric technique using ion selective electrodes: K1 = 2.0 M−1; K2 = 0.4 M−1 for the system PQ2+–Cl− and K1 = 5.3 M−1; K2 = 0.3 M−1 for DQ2+Br−.

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