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Mohapatra SK, Fonari A, Risko C, Yesudas K, Moudgil K, Delcamp JH, Timofeeva TV, Brédas JL, Marder SR, Barlow S. Dimers of Nineteen-Electron Sandwich Compounds: Crystal and Electronic Structures, and Comparison of Reducing Strengths. Chemistry 2014; 20:15385-94. [DOI: 10.1002/chem.201404007] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Indexed: 11/11/2022]
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Rüchardt C, Beckhaus HD. Steric and electronic substituent effects on the carbon-carbon bond. Top Curr Chem (Cham) 2005. [DOI: 10.1007/3-540-15810-3_1] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2023]
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Cao C, Yuan H. A new approach of evaluating bond dissociation energy from eigenvalue of bonding orbital-connection matrix for C-C and C-H bonds in alkane. JOURNAL OF CHEMICAL INFORMATION AND COMPUTER SCIENCES 2003; 43:600-8. [PMID: 12653527 DOI: 10.1021/ci020295v] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A new bonding orbital-connection matrix was constructed, in which the diagonal elements were assigned the chemical potentials E(1) and E(2) of two radicals R(i)* and R(j)* obtained by cutting the interested bond, and the off-diagonal elements, representing bonding connections, were assigned values 1. The eigenvalues X(1CC) and X(1CH) of the bonding orbital-connection matrix were obtained for C-C and C-H bonds, respectively. Also a steric effect parameter S(ij) was proposed for C-C bond. Using X(1CC), X(1CH), and S(ij) as bond descriptors, good correlations with the Bond Dissociation Energies (BDEs) of the C-C and C-H bonds were obtained for alkanes. The result shows that the eigenvalue of bonding orbital-connection matrix is a good descriptor for expressing the relative bond energies of C-C and C-H bonds in alkane. This work provides a new physical insight and a principally novel general approach to the evaluation of the bond dissociation energies of carbon-carbon (C-C) and carbon-hydrogen (C-H) bonds in alkane. Also it builds a simple bridge linking the adjacent matrix of radicals R(i)* and R(j)* with the BDE of R(i)-R(j) and R(i)-H. Furthermore, the Heat of Atomization (HA) and Heat of Formation in Gas (HFG(0)) of alkane can be estimated well with the parameters X(1CC), X(1CH), and S(ij).
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Affiliation(s)
- Chenzhong Cao
- Department of Chemistry, Xiangtan Normal University, Xiangtan, 411201, People's Republic of China.
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Zavitsas AA. The Relation between Bond Lengths and Dissociation Energies of Carbon−Carbon Bonds. J Phys Chem A 2003. [DOI: 10.1021/jp0269367] [Citation(s) in RCA: 152] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Andreas A. Zavitsas
- Department of Chemistry and Biochemistry, Long Island University, University Plaza, Brooklyn, New York 11201
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Rüchardt C, Gerst M, Ebenhoch J. Nichtkatalysierte Transferhydrierung und Transferhydrogenolyse: neue Wege der Wasserstoffübertragung. Angew Chem Int Ed Engl 1997. [DOI: 10.1002/ange.19971091306] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Suzuki T, Nishida JI, Tsuji T. Hexaphenylethan-Derivate mit neuartigem elektrochromem Verhalten. Angew Chem Int Ed Engl 1997. [DOI: 10.1002/ange.19971091226] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Welle FM, Beckhaus HD, Rüchardt C. Thermochemical Stability of alpha-Amino-alpha-carbonylmethyl Radicals and Their Resonance As Measured by ESR. J Org Chem 1997; 62:552-558. [PMID: 11671448 DOI: 10.1021/jo961703v] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
ESR spectra of the captodative alpha-amino-alpha-carbonylmethyl radicals 8 have been recorded. No coalescence temperature for the rotation of the two NMe groups was found at temperatures below the decomposition temperature of the radicals. From known coalescence temperatures and rotational barriers of substituted methyl radicals the rotational barrier of >/=17 kcal mol(-)(1) was estimated for the (*)C-N bond in the radicals 8. Enthalpies DeltaH(diss) and entropies DeltaS(diss) of the homolytic dissociation of 7a,c,d into 8a,c,d have been obtained from equilibrium measurements by ESR. By correcting for substituent interaction enthalpies in 7 (steric and geminal), a radical stabilization enthalpy RSE = -20.7 +/- 1.0 kcal mol(-)(1) was obtained for 8. By addition of the known RSEs of dialkylamino- and carbonyl groups, a RSE = -9.9 kcal mol(-)(1) is predicted for 8. The difference between the experimental and predicted values of 10.8 kcal mol(-)(1) is attributed to a synergistic captodative substituent effect. A linear correlation between the radical stabilization enthalpies of the radicals 8 and of other mono- and disubstituted alkyl radicals and their ESR aH(alpha) coupling constants was found. According to this correlation the reduction of aH(alpha) by 1 G corresponds to an increase in RSE of 1.57 kcal mol(-)(1). The large resonance of the captodative alpha-amino-alpha-carbonylmethyl radicals 3, expressed by their high RSE, their small aH(alpha) coupling constant, and their high rotational barrier, can be rationalized by a strong interaction between the alpha-amino and the alpha-carbonyl groups similar to that in amides and expressed in the resonance structures 6.
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Affiliation(s)
- Frank M. Welle
- Institut für Organische Chemie und Biochemie der Universität Freiburg, Albertstr. 21, D-79104 Freiburg i. Br., Germany
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Welle FM, Verevkin SP, Beckhaus HD, Rüchardt C. Substituent Effects on the CC Bond Strength, 20. – Geminal Substituent Effects, 14. – Stabilization of the Cyano(dimethylamino)methyl Radical – Synergistic effect Due to Interaction Between α-Amino and α-Cyano Groups on the Radical Stabilization Energy. ACTA ACUST UNITED AC 1997. [DOI: 10.1002/jlac.199719970122] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Maslak P, Chapman WH. Mesolytic Scission of C-C Bonds as a Probe for Photoinduced Electron Transfer Reactions of Quinones. J Org Chem 1996; 61:2647-2656. [PMID: 11667094 DOI: 10.1021/jo952102r] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Photoinduced electron transfer reactions of chlorinated benzoquinones are investigated using bibenzylic donors that undergo rapid fragmentation upon oxidation. The fragmentation rates and the quantum yields are used to probe the dynamics of back-electron transfer (BET) in two types of radical ion pairs. The triplet ion pairs formed by interception of excited state quinones give products with high quantum yields. The singlet ion pairs formed by irradiation of the charge-transfer (CT) complexes between the quinones and the donors undergo reactions with significantly lower efficiency. The advantage of the first method (triplet quenching) over the CT-irradiation depends on the energetics of BET. It is large for reactions with relatively small DeltaG(et) for BET and it decreases for reactions with more negative DeltaG(bet). The indirectly obtained rates of BET are in excellent agreement with literature data for similar, but unreactive systems, and the rates of C-C bond scission in radical cations generated in these systems are consistent with the thermodynamics of these processes.
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Affiliation(s)
- Przemyslaw Maslak
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
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Herberg C, Peyman A, Nölke M, Beckhaus HD, Rüchardt C. Substituent effects on the CC bond strength, 18. Stabilization of alkyl radicals by 4-pyridyl, 1-naphthyl or 2-naphthyl substituents in α-position. European J Org Chem 1995. [DOI: 10.1002/jlac.1995199505128] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Maslak P, Vallombroso TM, Chapman WH, Narvaez JN. Free-Energy Relationship for Mesolytic Cleavage of C?C Bonds. ACTA ACUST UNITED AC 1994. [DOI: 10.1002/anie.199400731] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Maslak P, Chapman WH, Narvaez JN, Vallombroso TM. Gibbs-Energie-Beziehung für die mesolytische Spaltung von C-C-Bindungen. Angew Chem Int Ed Engl 1994. [DOI: 10.1002/ange.19941060123] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Birkhofer H, Beckhaus HD, Peters K, Schnering HGV, Rüchardt C. Substituenteneffekte auf die C–C-Bindungsstärke, 12[1]. Thermolysen aromatischer Pinakol-dimethylether zur Bestimmung der Stabilisierungsenergie von α-Methoxybenzyl-Radikalen[2]. ACTA ACUST UNITED AC 1993. [DOI: 10.1002/cber.19931260728] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Schulze R, Beckhaus HD, Rüchardt C. Substituenteneffekte auf die CC-Bindungsstärke, 13. Kinetische und thermodynamische Stabilität von α1-alkylierten α1-Amino-carbonsäureestern – Stabilisierungsenergie von α1-Amino-α1-(ethoxycarbonyl)alkyl-Radikalen. ACTA ACUST UNITED AC 1993. [DOI: 10.1002/cber.19931260425] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Pakusch J, Beckhaus HD, Rüchardt C. Substituenteneffekte auf die CC-Bindungsstärke, 10. Resonanzstabilisierung von Alkylradikalen durch zwei geminale Cyangruppen. ACTA ACUST UNITED AC 1991. [DOI: 10.1002/cber.19911240535] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Maslak P, Narvaez JN. Mesolytische Spaltung von C-C-Bindungen, ein Vergleich mit homolytischen und heterolytischen Prozessen am gleichen Substrat. Angew Chem Int Ed Engl 1990. [DOI: 10.1002/ange.19901020315] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Maslak P, Chapman WH. Dicyanobenzene sensitized carbon-carbon bond cleavage in methoxybicumenes. Products and mechanistic studies. Tetrahedron 1990. [DOI: 10.1016/s0040-4020(01)88366-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Peyman A, Hickl E, Beckhaus HD. Anwendung von Kraftfeldrechnungen, 7 Synthese und Thermolyse 1,1′-disubstituiertertrans-Azoneopentane. – Resonanzeffekt und sterischer Einfluß der Substituenten auf die thermische Stabilität sekundärer Azoalkane. ACTA ACUST UNITED AC 1987. [DOI: 10.1002/cber.19871200508] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Okamoto A, Snow MS, Arnold DR. Photosensitized (electron transfer) carbon-carbon bond cleavage of radical cations. Tetrahedron 1986. [DOI: 10.1016/s0040-4020(01)88078-9] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Meer MAFT, Beckhaus HD, Peters K, von Schnering HG, Rüchardt C. Thermolabile Hydrocarbons, XXVII. 2,3-Di-1-adamantyl-2,3-dimethylbutane; Long Bonds and Low Thermal Stability. ACTA ACUST UNITED AC 1985. [DOI: 10.1002/cber.19851181203] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Bernlöhr W, Beckhaus HD, Lindner HJ, Rüchardt C. Thermolabile Kohlenwasserstoffe, XXV1). Zusammenhänge zwischen thermischer Stabilität, Spannung und Struktur von 1,1′-Diphenyl-1,1′-bicycloalkylen. ACTA ACUST UNITED AC 1984. [DOI: 10.1002/cber.19841171115] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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