101
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Schuster DI, Resnick BM. Photochemistry of ketones in solution. XLI. Absolute stereochemistry of photorearrangement of a simple chiral 4,4-dialkylcyclohexenone. J Am Chem Soc 2002. [DOI: 10.1021/ja00826a067] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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102
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Schuster DI, Wang L. Photochemistry of ketones in solution. 70. Stereospecific photodecarbonylation of cis- and trans-2,7-dimethyl-3,5-cycloheptadienone: observation of an apparent symmetry-forbidden concerted cheletropic fragmentation. J Am Chem Soc 2002. [DOI: 10.1021/ja00347a065] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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103
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Schuster DI, Prabhu KV. Photochemistry of ketones in solution. XXXIX. 3,4-Dimethyl-4-trichloromethyl-2,5-cyclohexadien-1-one. J Am Chem Soc 2002. [DOI: 10.1021/ja00818a026] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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104
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Schuster DI, Hussain S. Photochemistry of ketones in solution. 57. Synthesis and photochemistry of a constrained 2-cyclohexenone. J Am Chem Soc 2002. [DOI: 10.1021/ja00521a085] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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105
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Lem G, Kaprinidis NA, Schuster DI, Ghatlia ND, Turro NJ. Regioselective photodimerization of enones in zeolites. J Am Chem Soc 2002. [DOI: 10.1021/ja00068a083] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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106
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Chang SLP, Schuster DI. Fluorescence quenching of 9,10-dicyanoanthracene by dienes and alkenes. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100297a036] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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107
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108
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Lem G, Schuster DI, Courtney SH, Lu Q, Wilson SR. Addition of Alcohols and Hydrocarbons to Fullerenes by Photosensitized Electron Transfer. J Am Chem Soc 2002. [DOI: 10.1021/ja00106a073] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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109
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Schuster DI, Patel DJ. The Radical Fragmentation Route on Photolysis of 2,5-Cyclohexadienones. 4-Methyl-4-trichloromethyl-2,5-cyclohexadienone1,2. J Am Chem Soc 2002. [DOI: 10.1021/ja01089a053] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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110
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Patel DJ, Schuster DI. Photochemistry of 4-methyl-4-trichloromethyl-2,5-cyclohexadienone. I. The nature of the products. J Am Chem Soc 2002. [DOI: 10.1021/ja01021a015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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111
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Schuster DI, Goldstein MD, Bane P. Photochemistry of unsaturated ketones in solution. 51. Photophysical and photochemical studies of Michler's ketone. J Am Chem Soc 2002. [DOI: 10.1021/ja00443a034] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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112
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Schuster DI, Kaprinidis N, Wink DJ, Dewan JC. Stereochemistry of [2 + 2] photocycloaddition of cyclic enones to alkenes: structural and mechanistic considerations in formation of trans-fused cycloadducts. J Org Chem 2002. [DOI: 10.1021/jo00002a016] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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113
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Schuster DI, Rao JM. Alkyl substituent effects on the photorearrangement of cyclohex-2-en-1-ones to lumiketones. J Org Chem 2002. [DOI: 10.1021/jo00321a001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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114
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Schuster DI. Mechanisms of photochemical transformations of cross-conjugated cyclohexadienones. Acc Chem Res 2002. [DOI: 10.1021/ar50122a003] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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115
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Schuster DI, Kim CW. Site selectivity on hydrogenation of bicyclo[4.2.1]nona-2,4,7-trien-9-one. Possible effect of homoaromatic delocalization. J Org Chem 2002. [DOI: 10.1021/jo00892a029] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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116
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Schuster DI, Woning J, Kaprinidis NA, Pan Y, Cai B, Barra M, Rhodes CA. Photochemical and photophysical studies of bicyclo[4.3.0]non-1(6)-en-2-one. [Erratum to document cited in CA117(12):121274k]. J Am Chem Soc 2002. [DOI: 10.1021/ja00051a071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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117
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Schuster DI, Heibel GE, Brown PB, Turro NJ, Kumar CV. Are triplet exciplexes involved in [2 + 2] photocycloaddition of cyclic enones to alkenes? J Am Chem Soc 2002. [DOI: 10.1021/ja00232a063] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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118
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Schuster DI, Resnick BM. Photochemistry of unsaturated ketones in solution. XXVIII. Flash photolysis of a conjugated cyclohexenone. A reinvestigation. J Am Chem Soc 2002. [DOI: 10.1021/ja00728a061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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119
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Schuster DI, Weil TM, Halpern AM. Photochemistry of ketones in solution. XXXVI. Measurement of decay rates of triplet excited states using time-correlated single photon counting. Benzophenone triplets in aromatic solvents. J Am Chem Soc 2002. [DOI: 10.1021/ja00778a061] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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120
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Kaprinidis NA, Woning J, Schuster DI, Ghatlia ND. Photochemistry of steroidal ketones: formation of an exceptionally stable ketene by an .alpha.-cleavage reaction. J Org Chem 2002. [DOI: 10.1021/jo00028a067] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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121
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Schuster DI, Greenberg MM, Nunez IM, Tucker PC. Photochemistry of ketones in solutions. 70. Identification of the reactive electronic excited state in the photocycloaddition of alkenes to cyclic enones. J Org Chem 2002. [DOI: 10.1021/jo00163a043] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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122
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Schuster DI, Palmer JM, Dickerman SC. Selectivity in Hydride Reductions of Tropone. A Mechanism for Apparent Double Hydride Transfer. J Org Chem 2002. [DOI: 10.1021/jo01350a532] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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123
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Schuster DI, Smith KJ, Brisimitzakis AC, Van der Veen JM, Gruska RP. Photochemistry of ketones in solution. 61. Unprecedented rearrangement products from ultraviolet irradiation of a model 2,5-cyclohexadienone. J Org Chem 2002. [DOI: 10.1021/jo00315a056] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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124
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Schuster DI, Brizzolara DF. Mechanism of photoisomerization of cyclohexenones. 10-Hydroxymethyl-.DELTA.1,9-2-octalone. Question of hydrogen abstraction from benzene by ketone triplets. J Am Chem Soc 2002. [DOI: 10.1021/ja00717a037] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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125
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Schuster DI, Patel DJ. Stereospecificity and Solvent Control of Lumiproduct Formation vs. Fragmentation in Dienone Photochemistry1,2. J Am Chem Soc 2002. [DOI: 10.1021/ja00960a050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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126
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Schuster DI, Wang L, Van der Veen JM. Photochemistry of ketones in solution. Part 75. Photodecarbonylation of cis- and trans-2,7-dimethyl-3,5-cycloheptadienones: applicability of orbital symmetry theory to photochemical cheletropic fragmentations. J Am Chem Soc 2002. [DOI: 10.1021/ja00310a048] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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127
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Schuster DI, Underwood GR, Knudsen TP. Photochemistry of ketones in solution. XXX. Application of simple theoretical methods to the solution of chemical problems. V. Divergent behavior of singlet and triplet excited states of .beta.,.gamma.-unsaturated ketones. Explanation based on spin distribution. J Am Chem Soc 2002. [DOI: 10.1021/ja00746a043] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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128
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Schuster DI, Polowczyk CJ. The Photolysis of Spiro[2.5]octa-1,4-dien-3-one in Ethyl Ether. A Note on the Mechanism of Photolysis of 2,5-Cyclohexadienones. J Am Chem Soc 2002. [DOI: 10.1021/ja01074a066] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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129
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Schuster DI, Lem G, Kaprinidis NA. New insights into an old mechanism: [2 + 2] photocycloaddition of enones to alkenes. Chem Rev 2002. [DOI: 10.1021/cr00017a001] [Citation(s) in RCA: 230] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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130
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Zimmerman HE, Schuster DI. A New Approach to Mechanistic Organic Photochemistry. IV. Photochemical Rearrangements of 4,4-Diphenylcyclohexadienone. J Am Chem Soc 2002. [DOI: 10.1021/ja00882a032] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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131
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Schuster DI, Liu KC. Photochemistry of ketones in solution. XXXIII. Nucleophilic trapping of photochemically generated zwitterions. Evidence for the intermediacy of zwitterions in the photochemical rearrangement of cyclohexadienones. J Am Chem Soc 2002. [DOI: 10.1021/ja00753a083] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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132
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Schuster DI, Weil TM. Photochemistry of ketones in solution. XXXVIII. Mechanism for photoreduction of benzophenone in benzene. Evidence for self-quenching of benzophenone triplets in solution and for hydrogen abstreuction from benzophenone ground state. J Am Chem Soc 2002. [DOI: 10.1021/ja00793a068] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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133
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Schuster DI, Prabhu KV, Adcock S, Van der Veen J, Fujiwara H. Stereoselectivity in the photochemical rearrangement of 3,4-dimethyl-4-trichloromethyl-2,5-cyclohexadienone. J Am Chem Soc 2002. [DOI: 10.1021/ja00735a071] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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134
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Schuster DI, Calcaterra LT. Photochemistry of ketones in solution. 66. Experimental evidence for the intermediacy of singlet (S1) and triplet (T2) n,.pi.* states in the [1,3]-sigmatropic acyl shift of photoexcited 3-methyl-3-(1-cyclopentenyl)butan-2-one. J Am Chem Soc 2002. [DOI: 10.1021/ja00387a041] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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135
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Wilson SR, Kaprinidis N, Wu Y, Schuster DI. A new reaction of fullerenes: [2+2]-photocycloaddition of enones. J Am Chem Soc 2002. [DOI: 10.1021/ja00071a088] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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136
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Chan CB, Schuster DI. Photochemistry of ketones in solution. 64. Reactivity of n,.pi.* and .pi.,.pi.* triplet excited states of 4a-methyl-4,4a,9,10-tetrahydro-2(3H)-phenanthrone. J Am Chem Soc 2002. [DOI: 10.1021/ja00374a041] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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137
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Wilson SR, Wu Y, Kaprinidis NA, Schuster DI, Welch CJ. Resolution of enantiomers of cis- and trans-fused C60-enone [2+2] photoadducts. J Org Chem 2002. [DOI: 10.1021/jo00076a007] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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138
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Schuster DI, Brown RH, Resnick BM. Photochemistry of ketones in solution. 53. Stereospecific triplet-state photorearrangements of chiral 2-cyclohexenones: type A lumiketone rearrangement and phenyl migrations. J Am Chem Soc 2002. [DOI: 10.1021/ja00482a031] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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139
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Schuster DI, Dunn DA, Heibel GE, Brown PB, Rao JM, Woning J, Bonneau R. Enone photochemistry. Dynamic properties of triplet excited states of cyclic conjugated enones as revealed by transient absorption spectroscopy. J Am Chem Soc 2002. [DOI: 10.1021/ja00016a048] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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140
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Schuster DI, Eriksen J, Engel PS, Schexnayder MA. Photochemistry of ketones in solution. 50. Fluorescence lifetimes of .beta.,.gamma.-unsaturated ketones. Structural dependence of rate constants for reaction and decay of singlet excited states. J Am Chem Soc 2002. [DOI: 10.1021/ja00432a059] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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141
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Schuster DI, Jarowski PD, Kirschner AN, Wilson SR. Molecular modelling of fullerene–porphyrin dyads. ACTA ACUST UNITED AC 2002. [DOI: 10.1039/b201011a] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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142
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Wolff DJ, Barbieri CM, Richardson CF, Schuster DI, Wilson SR. Trisamine C(60)-fullerene adducts inhibit neuronal nitric oxide synthase by acting as highly potent calmodulin antagonists. Arch Biochem Biophys 2002; 399:130-41. [PMID: 11888198 DOI: 10.1006/abbi.2002.2766] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
C(60)-Fullerene trisamine adducts inhibit neuronal nitric oxide synthase and calcineurin phosphatase activities in a manner completely reversible by calmodulin. As measured by difference spectroscopy, D(3)-trisamine and C(3)-semiamine fullerene adducts displace trifluoperazine bound to calmodulin coincident with their binding. These binding events are complete at a molar ratio of 4 mol added fullerene per mole calmodulin. Trisamine fullerene adducts alter the native electrophoretic mobility of calmodulin, producing a heterogeneity of bands with associated fullerene. D(3)- and C(3)-trisamine fullerene adducts interact with dansylated calmodulin, producing a 50% loss of maximal fluorescence at concentrations of 30 nM. At higher concentrations than those required to inhibit neuronal nitric oxide synthase, trisamine fullerene adducts inhibit nitric oxide formation by the cytokine-inducible nitric oxide synthase isoform. These inhibitions are fully reversible by calmodulin and skeletal muscle troponin C but not by skeletal muscle parvalbumin. Of the trisamine fullerene adducts tested only the C(3)- and D(3)-semiamine adducts inhibit Ca(2+)-dependent nitric oxide production in GH(3) pituitary cells. These observations support the proposal that trisamine C(60)-fullerene adducts are potent calmodulin antagonists, some of which display activity in intact cellular systems.
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143
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Wilson SR, Yurchenko ME, Schuster DI, Yurchenko EN, Sokolova O, Braslavsky SE, Klihm G. Preparation and photophysical studies of a fluorous phase-soluble fullerene derivative. J Am Chem Soc 2002; 124:1977-81. [PMID: 11866611 DOI: 10.1021/ja0119200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report the first synthesis of a well-characterized "Teflon ponytail" fullerene adduct (3) via the Hirsch-Bingel reaction with a malonate bearing two perfluorinated alkyl chains. This C3 tris-adduct shows excellent solubility in perfluorinated solvents, such as FC-72 and FC-75. Compound 3 was found to be an efficient sensitizer for singlet oxygen formation in fluorous media, which has potential in biphasic systems and in photobiology.
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144
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Schuster DI. Understanding and Manipulating Excited-State Processes. Molecular and Supramolecular Photochemistry. Vol. 8 Edited by V. Ramamurthy (Tulane University) and Kirk S. Schanze (University of Florida). Marcel Dekker, Inc.: New York, Basel. 2001. xx + 758 pp. $195.00. ISBN: 0-8247-0579-3. J Am Chem Soc 2002. [DOI: 10.1021/ja0153518] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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145
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Schuster DI, Rosenthal J, MacMahon S, Jarowski PD, Alabi CA, Guldi DM. Formation and photophysics of a stable concave–convex supramolecular complex of C60and a substituted s-triazine derivative. Chem Commun (Camb) 2002. [DOI: 10.1039/b207661f] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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146
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MacMahon S, Fong R, Baran PS, Safonov I, Wilson SR, Schuster DI. Synthetic approaches to a variety of covalently linked porphyrin--fullerene hybrids. J Org Chem 2001; 66:5449-55. [PMID: 11485469 DOI: 10.1021/jo010317x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
There is substantial interest in dyads in which C(60) is covalently linked to electron donors, such as porphyrins, which absorb light strongly in the visible region. We present here the details of the syntheses of such compounds, which can be broadly organized into categories depending upon the nature of the linker joining the two chromophores. The structural aspects of intramolecular electronic interaction that we have sought to explore have dictated the synthetic strategies employed to generate these classes of molecules. Flexible glycol linkers were used to allow close approach between the fullerene and porphyrin, facilitating through-space interactions. These linkers also allowed studies of the effects of metal cation complexation. Naphthalene and alkyne linkers were used to examine the possible effects a conjugated or aromatic linker might have on photophysical properties. Finally, steroids were used as linkers in dyads expected to possess a large distance between the two chromophores, in which only through-bond interactions between the fullerene and porphyrin should be possible.
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147
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Sun Y, Wilson SR, Schuster DI. High dissolution and strong light emission of carbon nanotubes in aromatic amine solvents. J Am Chem Soc 2001; 123:5348-9. [PMID: 11457398 DOI: 10.1021/ja0041730] [Citation(s) in RCA: 349] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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148
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Guo LW, Gao X, Zhang DW, Wu SH, Wu HM, Li YJ, Wilson SR, Richardson CF, Schuster DI. Alkaloid-fullerene systems through photocycloaddition reactions. J Org Chem 2000; 65:3804-10. [PMID: 10864768 DOI: 10.1021/jo000156h] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The photocycloaddition of tertiary amines to ¿60fullerene (C(60)) is an interesting and useful reaction. We wished to extend the applications of this type of reaction through an investigation of the photoaddition of alkaloids to C(60) for the purpose of synthesizing novel and complex photoadducts that are difficult to obtain by usual methods. Irradiation of tazettine (2) or gramine (3) with C(60) in toluene leads to formation of one monoadduct (6 or 7), whereas scandine (1a) or 10-hydroxyscandine (1b) reacts with C(60) photochemically to give two products, the expected ¿6,6 monoadduct (5a, 5b) and a new type of monoadduct with a bis-¿6, 6 closed structure (4a, 4b). These new structures were characterized by UV-vis, FT-IR, (1)H NMR, (13)C NMR, (1)H-(1)H COSY, ROESY, HMQC (heteronuclear multiple-quantum coherence), and HMBC (heteronuclear multiple-bond connectivity) spectroscopy. The techniques of time-of-flight secondary ion MS (TOF-SIMS) and field desorption MS (FD-MS) were used for the mass determination. (3)He NMR analysis of the product mixture from photoaddition of 1a to C(60) containing a (3)He atom ((3)He@C(60)) led to two peaks at -9.091 and -11.090 ppm relative to gaseous (3)He, consistent with formation of a ¿6, 6-closed monoadduct and a bis-¿6,6 closed adduct. Presumably, the bis-¿6, 6 closed adducts are formed by an intramolecular ¿2 + 2 cycloaddition of the vinyl group to the adjacent 6,6-ring junction of C(60) after the initial photocycloaddition.
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149
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Wolff DJ, Papoiu AD, Mialkowski K, Richardson CF, Schuster DI, Wilson SR. Inhibition of nitric oxide synthase isoforms by tris-malonyl-C(60)-fullerene adducts. Arch Biochem Biophys 2000; 378:216-23. [PMID: 10860539 DOI: 10.1006/abbi.2000.1843] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
C(3)-tris-malonyl-C(60)-fullerene and D(3)-tris-malonyl-C(60)-fullerene derivatives inhibit citrulline and NO formation by all three nitric oxide synthase isoforms in a manner fully reversible by dilution. The inhibition of citrulline formation by C(3)-tris-malonyl-C(60)-fullerene occurs with IC(50) values of 24, 17, and 123 microM for the neuronal, endothelial, and inducible nitric oxide synthase (NOS) isoforms, respectively. As measured at 100 microM l-arginine, neuronal NOS-catalyzed nitric oxide formation was inhibited 50% at a concentration of 25 microM C(3)-tris-malonyl-C(60)-fullerene. This inhibition was a multisite, positively cooperative inhibition with a Hill coefficient of 2.0. C(3)-tris-malonyl-C(60)-fullerene inhibited the arginine-independent NADPH-oxidase activity of nNOS with an IC(50) value of 22 microM but had no effects on its cytochrome c reductase activity at concentrations as high as 300 microM. The inhibition of nNOS activity by C(3)-tris-malonyl-C(60)-fullerene reduced the maximal velocity of product formation but did not alter the EC(50) value for activation by calmodulin. C(3)-tris-malonyl-C(60)-fullerene reduced the maximal velocity of citrulline formation by inducible NOS without altering the K(m) for l-arginine substrate or the EC(50) value for tetrahydrobiopterin cofactor. As measured by sucrose density gradient centrifugation, fully inhibitory concentrations of C(3)-tris-malonyl-C(60)-fullerene did not produce a dissociation of nNOS dimers into monomers. These observations are consistent with the proposal that C(3)-tris-malonyl-C(60)-fullerene inhibits the inter-subunit transfer of electrons, presumably by a reversible distortion of the dimer interface.
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