Study of redox reactions of bis(arene) chromium complexes by the rotating disk electrode technique IV. Electrochemical oxidation and ionization potentials of bis(arene) chromium complexes

Yur'eva, L. P.; Peregudova, Svetlana M.; Kravtsov, D. N.; Vasil’kov, A. Yu.; Nekrasov, L. N.; Asfandiarov, N. L.; Timoshenko, M. M.; Chizhov, Yu. V.

doi:10.1016/0022-328x(87)85196-3

Cited by 16 publications

(4 citation statements)

References 17 publications

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“…Chemical Reactions and Reduction of TCT. To form charge-transfer complexes and electron-transfer salts, TCT was reacted with tetrathiafulvalene (TTF) ( E 1/ 2 ° = +0.30 V vs SCE in MeCN), N , N , N ‘, N ‘-tetramethyl- p -phenylenediamine (TMPD) ( E 1/ 2 ° = +0.10 and 0.72 V), bis(mesitylene)chromium(0), Cr(mes) 2 ( E 1/ 2 ° = −0.92 V), Co II Cp* 2 (Cp* = pentamethylcyclopentadieneide) ( E 1/ 2 ° = −1.47 V), and the two-electron donor tetrakis(dimethylamino)ethylene, TDAE ( E 1/ 2 ° = −0.53 and −0.68 V) . The −0.39 V irreversible reduction potential for TCT requires strong reducing agents for electron transfer to occur and this is only expected for the latter three electron donors.…”

Section: Resultsmentioning

confidence: 99%

Chemical Reduction of 2,4,6-Tricyano-1,3,5-triazine and 1,3,5-Tricyanobenzene. Formation of Novel 4,4‘,6,6‘-Tetracyano-2,2‘-bitriazine and Its Radical Anion

et al. 2002

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Chemical reduction of 2,4,6-tricyano-1,3,5-triazine, TCT, results in the formation of an unstable radical anion that undergoes immediate dimerization at a ring carbon to form [C(12)N(12)](2-), [TCT](2)(2-), characterized by a long 1.570 (4) A central C[bond]C. [TCT](2)(2-) can decompose into the radical anion of 4,4',6,6'-tetracyano-2,2'-bitriazine, [TCBT]*-, the one-electron reduced form of planar (D(2h)) TCBT, which is also structurally characterized as the [TMPD][TCBT] charge-transfer complex (TMPD = N,N,N',N'-tetramethyl-p-phenylenediamine) with a 1.492 (2) A central sp(2)[bond]sp(2) C[bond]C. Although crystals could not be obtained for the radical anion [TCBT]*-, the electrochemistry (E degrees = +0.03 V), EPR (g = 2.003, (2)A((14)N) = 3.347 G, and (4)A((14)N) = 0.765 G and a line width of 0.24 G), and theoretical calculations support the formation of [TCBT]*-. In addition, thermolysis of [TCT](2)(2-) yields [TCBT]*-. Chemical reduction of 2,4,6-tricyanobenzene, TCB, forms an unstable radical anion that immediately undergoes dimerization at a ring carbon to form [C(12)H(6)N(6)](2-), [TCB](2)(2-), which has a long 1.560 (5) A central C[bond]C. Reaction of TCT with tetrathiafulvalene (TTF) forms structurally characterized [TTF][TCT], and in the presence of water, TCT hydrolyzes to 2,4-dicyano-6-hydroxy-s-triazine, DCTOH. In contrast, the reaction of TCT with TMPD forms [TMPD][TCT], which in the presence of water forms structurally characterized [HTMPD](+)[DCTO](-).

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Section: Resultsmentioning

confidence: 99%

Chemical Reduction of 2,4,6-Tricyano-1,3,5-triazine and 1,3,5-Tricyanobenzene. Formation of Novel 4,4‘,6,6‘-Tetracyano-2,2‘-bitriazine and Its Radical Anion

et al. 2002

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“…E 0 − IP Correlations and Ionization Potentials of Solvated Molecules. Since 1980 a number of linear correlations − between E 0 and experimental gas-phase IP's were established for structurally related organic and organometallic compounds, but up to now their physical meaning has not been recognized. Only some selected data are given below: …”

Section: Resultsmentioning

confidence: 99%

“…The finding of an essentially linear relationship with very similar parameters cannot be accidental. To reveal the underlying physical reasons, we revised all relevant available data concerning ferrocene derivatives and bis(benzene)chromium (BBCr) derivatives. − As a result, a representative data set covering a wide range of potentials from −0.98 to +1.3 V and IP's from 5.01 to 7.40 eV were obtained. After all electrochemical data were reduced to the same experimental conditions (reference electrode SCE, solvent dichloromethane, supporting electrolyte [Bu 4 N][B(C 6 F 5 ) 4 ]) with corresponding corrections, a generalized linear regression was obtained for these 28 sandwich Fe and Cr complexes with E 0 (Fc 0/+ ) = 0.46 V and E 0 (BBCr 0/+ ) = −0.66 V as reference points.…”

Section: Resultsmentioning

confidence: 99%

α,ω-Diferrocenyl Cumulene Molecular Wires Studied by Density Functional Theory

2004

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Density functional theory calculations for neutral and oxidized diferrocenyldiphenylcumulenes, [Fc(Ph)C n (Ph)Fc] with n ) 2, 4, 6, 8, were performed at the B3LYP/6-31G level without any restrictions in symmetry. Geometrically, of the four possible diasteromeric structures of the neutral cumulenes, no preferential conformation was revealed, and the calculated structures reproduce the experimental X-ray structural data quite well. The spin density of all mono-and dications is located on the iron atoms, but not on the cumulene chain. Calculations of the ionization potentials for monocations show a breakdown of Koopmans' theorem. A calibration procedure was proposed for evaluation of vertical ionization potentials, resulting in values with experimental accuracy. UV-visible absorptions are assigned in terms of their band maximums, transition energies, and bandwidths on the basis of deconvoluted experimental spectra and on the basis of comparison with structurally related compounds. Calculations of the characteristic high-frequency symmetric vibrations of the cumulene chain show a very good match with experimental Raman bands. Redox potentials in solution are calculated by a simplified model on the basis of empirical findings; the results reproduce the experimental half-wave potentials quite satisfactorily and allow an estimate of an electrochemical decay slope and an effective conjugation limit in these cumulene molecular wires. The structural, chemical, optical, electrochemical, and molecular orbital properties of 2-31 make ferrocenyl cumulenes very promising molecular objects with great potential in molecular-scale electronics in comparison with pure organic molecular wires.

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“…We have previously described the synthesis of a series of non-symmetric complexes (C 6 H 5 CN)Cr(C 6 H 5 R), where R = CN (2), H, CH 3 (3), OCH 3 , COCH 3 , Cl, F and CF 3 (4) (Nesmeyanov et al, 1981;Vasil'kov et al, 1982;Sergeev et al, 1984). Their ionization potentials and behavior in redox processes were studied (Yur'eva et al, 1987). The use of electrochemical methods allows one to quantitatively estimate the influence of substituents on the redox parameters of the compounds.…”

Section: Introductionmentioning

confidence: 99%

Substituent effects in bis(arene)chromium compounds containing a CN group in the aromatic ring

Khrustalev

Vasil’kov

Antipin

2005

Acta Crystallogr Sect B

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The crystal structures of Cr(PhCN)(2) (2), (PhCN)Cr(PhCH(3)) (3) and (PhCN)Cr(PhCF(3)) (4) prepared by means of the Metal Vapor Synthesis (MVS) technique have been determined. Compounds (2), (3) and (4) crystallize as discrete sandwich complexes having intrinsic C(2v)(mm2), C(s)(m) and C(1)(1) symmetries, respectively. The X-ray diffraction study has revealed a synperiplanar conformation for (2) and (3), and a synclinal conformation for (4) with a torsion angle (C(ipso)1-Centroid1-Centroid2-C(ipso)2) of phi = 63.5 degrees . The angles between the ligand planes are 2.2, 3.9 and 1.8 degrees , respectively. The Cr atom is slightly (by 0.04-0.06 A) displaced towards the substituents from the line connecting the centers of the opposite aromatic rings. The Cr-C(ipso) distances are 2.115 (2)-2.137 (2), 2.112 (2) and 2.185 (3) A for CN, CF(3) and CH(3) groups, respectively. The CN groups as well as the H atoms lie out of the C(6) ring planes and are bent towards the Cr atom, but the C atom of the CH(3) group also lying out of the C(6) ring plane is bent away from the Cr atom. The C atom of the CF(3) group is essentially coplanar to the C(6) ring plane. There are no unusual intermolecular contacts in the structures of (2)-(4).

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Study of redox reactions of bis(arene) chromium complexes by the rotating disk electrode technique IV. Electrochemical oxidation and ionization potentials of bis(arene) chromium complexes

Cited by 16 publications

References 17 publications

Chemical Reduction of 2,4,6-Tricyano-1,3,5-triazine and 1,3,5-Tricyanobenzene. Formation of Novel 4,4‘,6,6‘-Tetracyano-2,2‘-bitriazine and Its Radical Anion

Chemical Reduction of 2,4,6-Tricyano-1,3,5-triazine and 1,3,5-Tricyanobenzene. Formation of Novel 4,4‘,6,6‘-Tetracyano-2,2‘-bitriazine and Its Radical Anion

α,ω-Diferrocenyl Cumulene Molecular Wires Studied by Density Functional Theory

Substituent effects in bis(arene)chromium compounds containing a CN group in the aromatic ring

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