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The phenanthridinone heterocyclic system has attracted considerable attention in recent years due to the diverse array of physical, chemical and pharmacological properties demonstrated by natural and synthetic derivatives. As a consequence there has been considerable development of synthetic methodology for the synthesis of this and related heterocyclic ring systems. The synthetic literature is discussed and is compared with a direct arylation methodology for the intramolecular cyclization of tertiary (2-iodo)benzoylamides to generate the biaryl bond of these compounds. The efficient methodology allowed the synthesis of a number of previously unknown phenanthridinone products. The photoluminescent properties of representative examples were characterized and it is proposed that the previously unknown compound 1s reveals dual fluorescence in a manner similar to the known compound 1r.

The phenanthridinone heterocyclic system has attracted considerable attention in recent years due to the diverse array of physical, chemical and pharmacological properties demonstrated by natural and synthetic derivatives. As a consequence there has been considerable development of synthetic methodology for the synthesis of this and related heterocyclic ring systems. The synthetic literature is discussed and is compared with a direct arylation methodology for the intramolecular cyclization of tertiary (2-iodo)benzoylamides to generate the biaryl bond of these compounds. The efficient methodology allowed the synthesis of a number of previously unknown phenanthridinone products. The photoluminescent properties of representative examples were characterized and it is proposed that the previously unknown compound 1s reveals dual fluorescence in a manner similar to the known compound 1r.

Rate constants for the quenching of 1,3-indandione (1) triplet by olefins and by hydrogen and electron donors were obtained employing the laser flash photolysis technique in benzene solution. These rate constants ranged from 2.5x10(5) Lmol-1s-1 (for 2-propanol) to 5.9x10(9) Lmol-1s-1 (for DABCO). From the quenching rate constants by 1,3-cyclohexadiene, trans- and cis-stilbene a value between 49.3 and 52.4 kcal/mol was estimated for the energy of the triplet state of 1,3-indandione. The npi* character of this triplet state was evidenced by the quenching rate constants obtained when typical hydrogen donors were employed as quenchers. For 2-phenyl-1,3-indandione (2, R=phenyl) a fast Norrish type I reaction is operating which prevents the determination of kinetic and spectroscopic data of its triplet state.

Rate constants for the quenching of 1,3-indandione (1) triplet by olefins and by hydrogen and electron donors were obtained employing the laser flash photolysis technique in benzene solution. These rate constants ranged from 2.5x10(5) Lmol-1s-1 (for 2-propanol) to 5.9x10(9) Lmol-1s-1 (for DABCO). From the quenching rate constants by 1,3-cyclohexadiene, trans- and cis-stilbene a value between 49.3 and 52.4 kcal/mol was estimated for the energy of the triplet state of 1,3-indandione. The npi* character of this triplet state was evidenced by the quenching rate constants obtained when typical hydrogen donors were employed as quenchers. For 2-phenyl-1,3-indandione (2, R=phenyl) a fast Norrish type I reaction is operating which prevents the determination of kinetic and spectroscopic data of its triplet state.

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2021-11-19T00:04:03Z No. of bitstreams: 1 2019 - Romulo Correia Ferreira.pdf: 8143730 bytes, checksum: 59e974a1c44f2c81587bf799b0058a69 (MD5) Made available in DSpace on 2021-11-19T00:04:03Z (GMT). No. of bitstreams: 1 2019 - Romulo Correia Ferreira.pdf: 8143730 bytes, checksum: 59e974a1c44f2c81587bf799b0058a69 (MD5) Previous issue date: 2019-07-22 CAPES - Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior CNPq - Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico Studies by UV/Vis absorption spectroscopy, fluorescence emission and 77K phosphorescence emission indicated that the dimethoxylated xanthones 1,2-dimethoxy-9H-xanthen-9-one (1,2MX), 2,3-dimethoxy- 9H-xanthen-9-one (2,3MX) and 3,4-dimethoxy-9H-xanthen-9-one (3,4MX) present triplet excited state with a ??* configuration. Studies by laser flash photolysis (?exc=355 nm) were performed to investigate the reactivity of the triplet excited state of the dimethoxylated xanthones 1,2MX, 2,3MX and 3,4MX toward different types of quenchers. Quenching of 1,2MX, 2,3MX and 3,4MX by 1-methylnaphthalene and 1,3-cyclohexadiene, in acetonitrile, results in the formation of the corresponding triplet excited states through a triplet-triplet energy transfer process controlled by diffusion. The hydrogen transfer reaction of these dimethoxylated xanthones employing alcohols (methanol, ethanol and 2-propanol) and 1,4-cyclohexadiene occurs through the pure mechanism, with rate constants consistent with the involvement of a triplet excited state with ??* character, confirming the experimental results of the phosphorescence studies. In all cases the formation of the corresponding ketyl radicals was observed. Using the electron donors DABCO and triethylamine as quenchers of the triplet excited state of 1,2MX, 2,3MX and 3,4MX the formation of the corresponding radical anion by electron transfer was observed. On the other hand, quenching with phenol and its derivatives led to the formation of the ketyl/phenoxyl radical pair, while using indole or the methyl ester of N-acetyl tryptophan (NATME) the ketyl/indolyl radical pair was formed. In all cases, the reaction takes place through a mechanism involving an electron transfer coupled to an ultra-fast proton transfer. Comparing the quenching rate constants for the dimethoxylated xanthones1,2MX, 2,3MX and 3,4MX, it can be concluded that there is no relevant difference between their reactivities. Photolysis of 2,3MX in H2O/acetonitrile solution (1:1 v/v) (?exc=266 nm) resulted in its photoionization with the formation of the corresponding radical cation (?max~390 nm). The characterization of this radical cation through the use of the nucleophilic quenchers chloride, bromide and acetate lead to quenching rate constants with diffusion-controlled values. Finally, 1,2MX, 2,3MX and 3,4MX were used as photosensitizers for singlet oxygen formation, although presenting very low efficiency (? ?1O2: 1,2MX = 0.19; 2,3MX = 0.12 and 3,4MX = 0.06). Os estudos por espectroscopia de absor??o no UV/Vis, emiss?o de fluoresc?ncia e emiss?o de fosforesc?ncia a 77K indicaram que as xantonas dimetoxiladas 1,2-dimetoxi-9H-xanten-9-ona (1,2MX), 2,3-dimetoxi-9H-xanten-9-ona (2,3MX) e 3,4-dimetoxi-9H-xanten-9-ona (3,4MX) apresentam estado excitado triplete com configura??o ??*. Estudos por fot?lise por pulso de laser (?exc=355 nm) foram realizados a fim de investigar a reatividade do estado excitado triplete das xantonas dimetoxiladas 1,2MX, 2,3MX e 3,4MX com diferentes tipos de supressores. A supress?o de 1,2MX, 2,3MX e 3,4MX por 1-metilnaftaleno e 1,3-cicloexadieno, em acetonitrila, resulta na forma??o dos estados excitados triplete correspondentes, atrav?s de um processo de transfer?ncia de energia triplete-triplete controlado por difus?o. As rea??es de transfer?ncia de hidrog?nio dessas xantonas dimetoxiladas empregando ?lcoois (metanol, etanol e 2-propanol) e 1,4-cicloexadieno ocorrem atrav?s de um mecanismo puro, com constantes de velocidade condizentes com o envolvimento de um estado excitado caracter?stico de tripletes ??*, confirmando os resultados experimentais dos estudos de fosforesc?ncia. Em todos os casos observou-se a forma??o dos radicais cetila correspondentes. Empregando os doadores de el?tron (DABCO e trietilamina) como supressores do estado excitado triplete de 1,2MX, 2,3MX e 3,4MX, observou-se a forma??o do ?nion radical correspondente por transfer?ncia de el?tron. Por outro lado, a supress?o com fenol e seus derivados levou ? forma??o do par de radicais cetila/fenoxila, enquanto que com indol ou o ?ster met?lico do N-acetil-triptofano (NATME) houve a forma??o do par de radicais cetila/indolila. Em todos esses casos, a rea??o se passa por um mecanismo de transfer?ncia de el?tron acoplada a uma transfer?ncia de pr?ton ultra-r?pida. As constantes de velocidade de supress?o para as xantonas dimetoxiladas 1,2MX, 2,3MX e 3,4MX, mostraram que n?o h? diferen?a relevante entre as suas reatividades. A fot?lise de 2,3MX em uma solu??o de H2O/Acetonitrila (1:1 v/v) (266 nm) resultou na sua fotoioniza??o, com a forma??o do c?tion radical correspondente, (?max~390 nm). A caracteriza??o desse c?tion radical atrav?s do uso dos supressores nucleof?licos cloreto, brometo e acetato forneceu constantes de velocidade de supress?o com valores controlados pela difus?o. Finalmente, 1,2MX, 2,3MX e 3,4MX foram empregadas como fotossensibilizadores para a forma??o de oxig?nio singlete, apresentando efici?ncia muito baixa (? ?1O2: 1,2MX = 0,19; 2,3MX = 0,12 e 3,4MX = 0,06).

Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2017-05-09T14:28:22Z No. of bitstreams: 1 2016 - Leonardo Santos de Barros.pdf: 6766023 bytes, checksum: 16ce8cf6e87d3cfab0a3d73fc9a6e46c (MD5) Made available in DSpace on 2017-05-09T14:28:22Z (GMT). No. of bitstreams: 1 2016 - Leonardo Santos de Barros.pdf: 6766023 bytes, checksum: 16ce8cf6e87d3cfab0a3d73fc9a6e46c (MD5) Previous issue date: 2016-11-19 Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES The photochemical reactivity of chalcone (CH) nanocrystals and its fluorinated derivatives (CH4F, CH23F, CH25F, CH26F, CH34F, CH35F, PFCB and the DFC) in a suspension of aqueous CTAB (0.04 mM) was studied by ultraviolet spectroscopy (UV), hydrogen nuclear magnetic resonance (H1NMR) and dynamic light scattering (DLS). The suspension of chalcone nanocrystals was prepared by the reprecipitation method in an aqueous solution of CTAB. The ultraviolet spectrum for the chalcone nanocrystals prior to irradiation showed hypochromic and bathochromic effects when compared to the methanolic solution. The DLS spectrum for CH CH23F, CH25F, CH26F and PFCB nanocrystals in aqueous CTAB showed a polydispersed system containing three different particle sizes, whereas CH34F, CH35F and DFC nanocrystals showed a clear monodispersivity. After irradiation, the DLS spectrum for these nanocrystals did not show significant changes, however for the monodispersed chalcones a shift towards larger particle sizes was observed. After irradiation the UV spectrum for the chalcone nanocrystals indicated a hypochromic effect on the longer wavelength band, which may be related to the consumption of their E-isomer. The kinetic monitoring of the E-isomer consumption for the chalcones CH, CH4F, CH23F, CH25F, CH26F CH34F, CH35F, PFCB and DFC as a function of irradiation time indicated that after a certain time the reaction reaches a steady state, with no more changes on their absorbance. The H1NMR spectrum for the irradiation product of CH4F and CH23F showed the formation of a mixture of ?-, ??-, and ?-truxillic dimers. On the other hand, irradiation of CH25F and CH26F derivatives led to the formation of the ?-truxinic dimer. Photolysis of CH34F and CH35F nanocrystals showed the conversion of the reactant to a cyclobutane through a stereospecific reaction. For CH35F only the ?-truxillic dimer has been formed, in nearly 100% conversion. However, for nanocrystals of the chalcone CH34F the Z-isomer is formed together with the ?-truxillic dimer CH34F, which may be related to a chalcone fraction that was solubilized in the CTAB containing aqueous phase. Irradiation of DFC nanocrystals occurred at a conversion of almost 100% to the cycloaddition product, the ?-truxillic dimer. For chalcone (CH) a high yield formation of the Z-chalcone isomer and dimers that are not formed from its E-isomer was observed, while PFCB appeared as a stable molecule during the irradiation process, and the presence of the five fluorine atoms on the benzyl ring can account for its stability A reatividade fotoqu?mica de nanocristais de chalcona (CH) e seus derivados fluorados (CH4F, CH23F, CH25F, CH26F, CH34F, CH35F, PFCB e DFC) foi estudada por espectroscopia de ultravioleta (UV), Resson?ncia magn?tica nuclear de hidrog?nio (RMN1H) e Espalhamento de luz din?mico (DLS). A suspens?o dos nanocristais das chalconas foi preparada pelo m?todo de reprecipita??o em uma solu??o aquosa de CTAB. Os espectros no ultravioleta para a suspens?o dos nanocristais das chalconas antes da irradia??o mostraram um efeito hipocr?mico e batocr?mico em rela??o ? solu??o metan?lica. Os espectros de DLS para os nanocristais da suspens?o das chalconas em solu??o aquosa de CTAB se apresentaram como um sistema polidisperso apresentando 3 tamanhos de part?culas para CH, CH23F, CH25F, CH26F, PFCB e monodisperso para CH34F, CH35F e DFC. Ap?s a irradia??o n?o se observou mudan?as significativas na estrutura dos espectros de DLS para os nanocristais, ocorrendo um deslocamento para tamanhos de part?culas maiores nas chalconas monodispersas. O espectro de UV para a suspens?o dos nanocristais das chalconas ap?s a irradia??o indicou um efeito hipocr?mico da banda de maior absor??o, o que pode estar relacionado ao consumo dos compostos de configura??o E. O acompanhamento cin?tico do consumo do is?mero E das chalconas CH, CH4F, CH23F, CH25F, CH26F CH34F, CH35F, PFCB e DFC contra tempo de irradia??o de uma suspens?o dos nanocristais destas chalconas em solu??o aquosa de CTAB (0,04 mM) indicou que a partir de um determinado tempo a rea??o atinge um estado estacion?rio, n?o apresentando mais mudan?as em sua absorb?ncia. Os espectros de RMN1H para o produto da irradia??o dos nanocristais das chalconas contendo fl?or na posi??o 4 (CH4F) e nas posi??es 2 e 3 (CH23F) mostraram a forma??o de uma mistura de d?meros ?????? e ?-trux?licos. A irradia??o dos derivados CH25F e CH26F levou ? forma??o do d?mero do tipo ?-trux?nico. Para os derivados CH34F e CH35F a convers?o dos reagentes ao fotociclobutano foi feita em uma forma estereoespec?fica, tendo sido formado somente o d?mero ?-trux?lico, com uma convers?o de quase 100% para o CH35F. No entanto, para os nanocristais da chalcona CH34F o is?mero Z-CH34F foi formado juntamente com o d?mero ?-trux?lico, o que pode estar relacionado a fra??es da chalcona que ficaram solubilizadas na fase aquosa contendo CTAB e n?o formaram suspens?o de nanocristais. A irradia??o dos nanocristais da chalcona DFC ocorreu com uma convers?o de quase 100% ao produto de fotocicloadi??o, sendo o d?mero formado o do tipo ?-trux?lico. Para chalcona (CH) observou-se um elevado rendimento de forma??o do is?mero Z-chalcona e de d?meros que n?o s?o provenientes do is?mero E, enquanto que PFCB apresentou-se como uma mol?cula est?vel durante o processo de irradia??o, com a presen?a dos cinco ?tomos de fl?or no anel benz?lico podendo ser respons?vel pela sua estabilidade

Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2017-01-12T11:50:46Z No. of bitstreams: 1 2016 - Otavio Augusto Chaves.pdf: 6300833 bytes, checksum: 156947ce06fa4e3b0674f5eaeaa4ef06 (MD5) Made available in DSpace on 2017-01-12T11:50:46Z (GMT). No. of bitstreams: 1 2016 - Otavio Augusto Chaves.pdf: 6300833 bytes, checksum: 156947ce06fa4e3b0674f5eaeaa4ef06 (MD5) Previous issue date: 2016-07-19 CNPq - Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico The interactions between human serum albumin (HSA) with 18-PF, BZL, MTZ and MZ and between bovine serum albumin (BSA) with t-DCTN, PF, LF-B, PIA and ?-lap were studied by spectroscopic techniques (molecular absorption in the UV-Vis region, circular dichroism, emission fluorescence in the steady state and temporal resolution) under physiological conditions. Theoretical calculations by molecular docking were performed to complement the experimental data and thus offer accurate to the results. The results obtained for the fluorescence quenching rate constant (kq) is greater than the diffusion rate constant in water (kdiff ? 5,00x109 L/mol), indicating that there is formation of complex between albumin and biologically active molecules in the ground state (for the sample PIA we confirmed this data with time resolved fluorescence experiments). For t-DCTN and LF-B beyond the static mechanism it was observed the presence of dynamic fluorescence quenching mechanism. Finally, for PF and PIA F?rster theory shows that the energy transfer between the fluorophore and the quenchers can occurs with high probability. The thermodynamic values for Gibbs? free energy are in accordance with the spontaneity of the association, for all the samples. Thermodynamic parameters ?H? and ?S? provided evidence of the main intermolecular interactions in the association. The samples 18-FP, t-DCTN, LF-B, PIA, ?-lap, BZL and MTZ interact with albumin by hydrogen bonding and hydrophobic interactions. On the other hand, PF and MZ interact by hydrogen bonding and electrostatic forces. The number of binding sites shows that there is only one main cavity of the protein to the interaction. For 18-PF, PF and LF-B the binding is weak, for t-DCTN the binding is moderate and for PIA, ?-lap, BZL, MTZ and MZ the binding is strong. Circular dichroism results show that upon binding of samples with the albumin there are no significant perturbations on the secondary structure of the protein. Theoretical calculations by molecular docking are in full agreement with the spectroscopic results As intera??es entre albumina s?rica humana (ASH) com 18-FP, BZL, MTZ e MZ e entre albumina s?rica bovina (ASB) com t-DCTN, PF, LF-B, PIA e ?-lap foram estudadas por t?cnicas espectrosc?picas (absor??o molecular no UV-Vis, dicro?smo circular, emiss?o de fluoresc?ncia no estado estacion?rio e com resolu??o temporal) sobre condi??es fisiol?gicas. C?lculos te?ricos por ancoramento molecular (do ingl?s molecular docking) foram executados para complementa??o dos dados experimentais e dessa forma obter resultados mais precisos. Os resultados obtidos para as constantes de velocidade de supress?o de fluoresc?ncia das albuminas (kq) s?o maiores do que a velocidade de difus?o em ?gua (kdiff ? 5,00x109 L/mols), indicando que h? forma??o de um complexo no estado fundamental entre as albuminas com as mol?culas biologicamente ativas (para amostra PIA tal dado foi confirmado com a fluoresc?ncia resolvida no tempo). Para as amostras t-DCTN e LF-B al?m do mecanismo est?tico foi observado ? presen?a do mecanismo din?mico e j? para as amostras PF e PIA o c?lculo de F?rster mostra alta probabilidade de ocorr?ncia de transfer?ncia de energia entre o fluor?foro e os supressores. Os valores termodin?micos de energia livre de Gibbs, calculados para todas as amostras est?o de acordo com a espontaneidade da associa??o. Par?metros termodin?micos de ?H? e ?S? forneceram ind?cios das principais intera??es intermoleculares na associa??o. As amostras 18-FP, t-DCTN, LF-B, PIA, ?-lap, BZL e MTZ associam com a albumina via liga??o de hidrog?nio e intera??es hidrof?bicas e j? PF e MZ por liga??o de hidrog?nio e intera??es eletrost?ticas. O n?mero de s?tios de liga??o para todas as amostras indicam que h? apenas uma principal cavidade da prote?na para a associa??o das mol?culas estudadas, sendo que essa associa??o ? moderada para 18-FP, PF e LF-B, fraca para t-DCTN e forte para PIA, ?-lap, BZL, MTZ e MZ. Estudos de dicro?smo circular demonstram que n?o h? perturba??es significativas na estrutura secund?ria da albumina com a associa??o. C?lculos te?ricos via ancoramento molecular est?o em total acordo com os resultados espectrosc?picos

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-05-10T19:35:53Z No. of bitstreams: 1 2016 - Julio Eduardo Paiva Sena Maia.pdf: 4252378 bytes, checksum: c4558d5e8e37e740e16bcf9b41d1c55b (MD5) Made available in DSpace on 2017-05-10T19:35:53Z (GMT). No. of bitstreams: 1 2016 - Julio Eduardo Paiva Sena Maia.pdf: 4252378 bytes, checksum: c4558d5e8e37e740e16bcf9b41d1c55b (MD5) Previous issue date: 2016-06-10 Laser flash photolysis (LFP) studies have been performed in order to investigate the triplet reactivity toward hydrogen and electron donors of the benzo-fused furan psoralens 3-ethoxycarbonyl-2H-benzofuro [2,3-e]-1-benzopyran-2-one (1) and 3-ethoxycarbonyl-2H-benzofuro[3,2-d]-1-benzopyran-2-one (2). Photolysis of the psoralens 1 and 2 results in the formation of the corresponding triplet excited state which is efficiently quenched by DABCO, triethylamine and phenols containing polar substituents. The reaction of the triplet state of 1 and 2 with electron donors (DABCO and triethylamine) leads to the formation of the corresponding anion radical whereas with phenols the corresponding aryloxyl radical was easily detected. Quenching rate constants for psoralen 2 are at least one order of magnitude greater than for 1. The Hammett plot for the reaction of 1 and 2 with phenols yielded a reaction constant ? of - 1.88?0.29 and -1.60?0.21, respectively, which reflects the high electrophilicity of the carbonyl group of both psoralens. Estudos empregando a t?cnica de Fot?lise por Pulso de Laser foram realizados a fim de investigar a reatividade dos estados excitados triplete dos benzopsoralenos 3-etoxicarbonil-2-H-benzofuro [2,3-e]-1-benzopiran-2-ona (Pso 1) e 3-etoxicarbonil-2-H-benzofuro[3,2-d]-1-benzopiran-2-ona (Pso 2) frente a doadores de el?tron e hidrog?nio. A fot?lise dos psoralenos Pso 1 e Pso 2 resulta na forma??o do estado excitado triplete correspondente os quais reagem de forma eficiente com DABCO, trietilamina, fenol e seus derivados contendo substituintes polares. A rea??o dos estados excitados triplete de Pso 1 e Pso 2 com doadores de el?tron (DABCO e trietilamina) levou ? forma??o do ?nion radical correspondente, enquanto que na presen?a de doadores de hidrog?nio como o fenol e seus derivados houve forma??o dos radicais fenoxila correspondentes. As constantes de velocidade obtidos para Pso 2 s?o pelo menos uma ordem de grandeza maior do que as obtidas para Pso 1. Um gr?fico de Hammett para as rea??es do triplete de Pso 1 e Pso 2 frente a fen?is e seus derivados produziu constante de rea??o (?? de - 1,88?0,29 e de -1,60 ? 0,21, respectivamente, o que reflete a alta eletrofilicidade do grupo carbon?lico para ambos os benzopsoralenos.

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2019-05-09T18:14:58Z No. of bitstreams: 1 2014 - Cosme Henrique Co?lho dos Santos de Oliveira.pdf: 3059616 bytes, checksum: 7069e5519179fda62853e8818d421b6c (MD5) Made available in DSpace on 2019-05-09T18:14:58Z (GMT). No. of bitstreams: 1 2014 - Cosme Henrique Co?lho dos Santos de Oliveira.pdf: 3059616 bytes, checksum: 7069e5519179fda62853e8818d421b6c (MD5) Previous issue date: 2014-05-19 CAPES The interaction between human serum albumin and derivatives 1,2-naphtoquinones in buffered solution was studied by UV - Visible, circular dichroism spectroscopy, fluorescence emission spectroscopy and fluorescence emission spectroscopy with temporal resolution. The results obtained for the rate constants of fluorescence quenching of HSA [Kq = 1012 L . (mol.s)-1] and fluorescence lifetime ?2 (? 6.6 ns ) suggest a static mechanism for the quenching process . Thermodynamic values for Gibbs energy free found for the interaction between 1,2-naphtoquinones and ASH (? -24 to -29 kJ . mol-1) suggest the occurrence of a spontaneous process via reversible mechanism. Already positive and negative values of ?Ho and ?So found in all cases (-6.60 to -21.82 kJ/mol and a +64.61 to 10.79 J/mol.K), respectively , indicating that the interaction occurs by formation of a hydrogen bond at room hydrophobic . Studies about distances of the rays of Foster, r, between donor and acceptor (? 2-3 nm), indicates a strong interaction between 1,2-naphthoquinone and ASH, which is independent of temperature. The decrease in the percentage of ?-helix verified in studies of circular dichroism (53 to 60%) indicating the interaction between HSA with 1,2-naphthoquinonas which may reflect the conformational change of the protein to better accommodate the compounds in the hydrophobic cavity serum albumin near the tryptophan residue. A intera??o entre albumina s?rica humana (ASH) e os derivados da 1,2-naftoquinona (LF, LF4Me, LF24Me, LF4Br, LF4Cl, LP4F,LP4Me e LP24Me), em solu??o tamponada (PBS, pH = 7,4), foi estudada por espectroscopia no ultravioleta-vis?vel (UV-Vis), dicro?smo circular (DC), espectroscopia de emiss?o de fluoresc?ncia e espectroscopia de emiss?o de fluoresc?ncia com resolu??o temporal. Os resultados obtidos para as constantes de velocidade supress?o de fluoresc?ncia de ASH (kq ? 1012 L/mol.s) e para o tempo de vida de fluoresc?ncia ?2 (? 6,6 ns) sugerem um mecanismo est?tico para o processo de supress?o. Os valores termodin?micos de energia livre de Gibbs, encontrados para a intera??o das 1,2-naftoquinonas com a ASH (? -24 a -29 kJ/mol) sugerem a ocorr?ncia de um processo espont?neo via um mecanismo revers?vel. J? os valores negativos de ?H? e positivos de ?S? encontrados em todos os casos (-6,60 a -21,82 kJ/mol e +10,79 a +64,61 J/mol.K, respectivamente) indicam que o processo de intera??o ocorre pela forma??o de uma liga??o de hidrog?nio em ambiente hidrof?bico. Os estudos das distancias do raio de F?srter r, entre doador e aceptor, (? 2 a 3 nm), indica a ocorr?ncia de uma forte intera??o entre 1,2-naftoquinona/ASH que independe da temperatura. A diminui??o na porcentagem de h?lice-? verificado nos estudos de dicro?smo circular (? 60 a 53 %) indicam a ocorr?ncia da intera??o entre as 1,2-naftoquinonas com ASH o que pode ser reflexo da mudan?a conformacional da prote?na para acomodar melhor os compostos na cavidade hidrof?bica da albumina s?rica pr?ximo ao res?duo de triptofano.

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-02-15T17:02:45Z No. of bitstreams: 1 2009 - William Pereira.pdf: 3794972 bytes, checksum: 64fbf9758bbf44329031caf3b369b79a (MD5) Made available in DSpace on 2017-02-15T17:02:45Z (GMT). No. of bitstreams: 1 2009 - William Pereira.pdf: 3794972 bytes, checksum: 64fbf9758bbf44329031caf3b369b79a (MD5) Previous issue date: 2009-10-22 CAPES The present study has two specific phases: Early, was studied the isathine irradiation with the presence of diisopropil-phosphoril-dimethylidrazone (diisopfh), in chloroform, at room temperature and 300nm. The structure of photo-product was elucidated by GC/MS, IR, NMR 1H, 13C and 31P, as well as hety-cosy, homo-cosy and other techniques. The proposal mechanism involve a bi-radical from triplet excited state of isathine that react with C=N of the diisopfh and has a ring expansion. The successive pass would be thermal and with propanone elimination, as thermal rearrangement on phosphoric derivates described in the literature. In a second phase was studied, by Laser Flash Photolysis, the kinetic effect of the six aromatic derived of phosphoril-hidrazone (H, p-Cl, p-NO2, p-CN, p-NMe2 e p-CO2H) on the triplet excited state of four aromatic ketones: Xanthone, Tioxanthone, Benzophenone and Benzyl. The observed process to quencher, in all cases, was energy transference, because the rate constants are in the order of 1010M-1s-1. In this form was possible to estimate the energy of triplet excited state of these six phosphoril-hidrazone derivates. O presente estudo divide-se em duas etapas bem distintas: Inicialmente, estudou-se a irradia??o de isatina na presen?a de diisopropil-dimetilfosforilidrazona (diisopfh) em clorof?rmio, a temperatura ambiente e comprimento de onda de 300nm. H? forma??o de um produto majorit?rio cujo peso molecular corresponde ? soma dos reagentes, diminu?do de 58g/mol. A estrutura deste produto foi elucidada por CG/EM, IV e RMN de 1H, 13C e 31P, al?m de t?cnicas como homocosy, hetycosy e outros. Prop?e-se um mecanismo via bi-radical formado a partir do estado excitado triplete da isatina com a liga??o C=N do composto diisopfh e conseq?ente expans?o do anel isat?nico; levando ? forma??o de um prov?vel produto fotoqu?mico prim?rio resultante de cicloadi??o. Numa segunda etapa, por processo t?rmico de elimina??o de propanona, similar a processo descrito na literatura por Olah, levaria a forma??o do fotoproduto detectado (derivado fosforil-benzodiazep?nico). Numa segunda etapa, estudou-se, por Fot?lise por Pulso de laser, o efeito cin?tico da presen?a de seis derivados arom?ticos de fosforilidrazona (H, p-Cl, p-NO2, p-CN, p-N (CH3)2 e p-CO2H) sobre o estado excitado triplete de quatro cetonas arom?ticas: tioxantona, xantona, benzofenona e benzil, todos em solu??o de acetonitrila. As constantes de velocidades obtidas (da ordem de difus?o da acetonitrila 1,9x1010 M-1s-1) indicam que o processo de supress?o de estado excitado se faz por transfer?ncia de energia. Desta forma foi poss?vel estimar a energia de estado excitado triplete destes derivados arom?ticos de fosforilidrazona.

Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2020-12-01T13:16:24Z No. of bitstreams: 1 2005 - Janaina de Faria Rodrigues.pdf: 1196806 bytes, checksum: f61a437bf82c569086de5d2f6df540e1 (MD5) Made available in DSpace on 2020-12-01T13:16:24Z (GMT). No. of bitstreams: 1 2005 - Janaina de Faria Rodrigues.pdf: 1196806 bytes, checksum: f61a437bf82c569086de5d2f6df540e1 (MD5) Previous issue date: 2005-08-19 Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq This work had as objective the determination of the rate constants for quenching of triplet state excited of Thioxanthone by hydrogen, electron and energy donors, being by the nanossecond laser flash photolysis technique in Acetonitrile solution. Also were studied its behavior in solvents of differents polarities. The substance produced in commercial scale and, for exemple, is a photoinitiator in photopolymerization reactions. The study of its photochemistry reactions with differents quencchers is necessary to analysis of possible transients. The obtained results show rate constants of reaction are of the order of (1,98 ? 0,04) x 1010 to (1,96 ? 0,04) x 105 L. mol-1, that depends on the process involved in the suppression reaction: energy, electron transfer or abstraction of hydrogen. Preliminary analyses demonstrate that the state excited triplet of lower energy of Thioxanthone presents a character n?*, in other words, there is no inversion of states triplet, although it is still necessary to accomplish other experiments for this confirmation Este trabalho teve como alvo de pesquisa a determina??o das constantes de velocidade da rea??o de supress?o do estado excitado triplete de tioxantona empregando-se a t?cnica de fot?lise por pulso de laser em nanossegundo, em acetonitrila, bem como o seu comportamento frente a varia??o da polaridade do meio. O interesse no estudo fotoqu?mico deste composto se deu por ser esta subst?ncia produzida em escala comercial e por ter uma grande ?rea de aplica??o, inclusive na ?rea fotoqu?mica sendo utilizada, por exemplo, como fotoiniciadora de processos de polimeriza??o e que apesar disto, ainda n?o havia sido realizado o seu estudo fotoqu?mico. Os resultados obtidos mostram uma varia??o das constantes de velocidade de supress?o do triplete de tioxantona que vai de (1,98 ? 0,04) x 1010 L . mol-1 a (1,96 ? 0,04) x 105 L . mol-1, dependendo do processo envolvido na rea??o de supress?o: transfer?ncia de energia, transfer?ncia de el?tron ou abstra??o de hidrog?nio. An?lises preliminares demonstram que o estado excitado triplete de mais baixa energia da Tioxantona apresenta um car?ter n?*, ou seja, n?o h? invers?o de estados triplete, embora ainda seja necess?rio realizar outros experimentos para esta confirma??o.