S?ntese e investiga??o fotof?sica de difluoroboro flavanonas in?ditas.

Programa de P?s-Gradua??o em Qu?mica. Departamento de Qu?mica, Instituto de Ci?ncias Exatas e Biol?gicas, Universidade Federal de Ouro Preto.Os complexos ?-dicetonatos de difluoroboro s?o altamente luminescentes apresentando v?rias propriedades como forte fluoresc?ncia, tanto em solu??o quanto no estado s?lido, e grandes coeficientes de extin??o molar. Devido ?s suas ricas propriedades ?ticas, estes compostos mostram amplas aplica??es em diversas ?reas dentro da qu?mica sint?tica e a eletr?nica org?nica como em automontagens e aplica??es em biossensores, bio-imagens e dispositivos optoeletr?nicos. O f?cil e r?pido processo de s?ntese faz ainda mais atrativo o desenvolvimento deste tipo de compostos, pois permite obter uma grande variedade de mol?culas com diferentes padr?es de substitui??o. S?o amplamente conhecidos os estudos de s?ntese dos compostos derivados de ?-dicetonatos assim como tamb?m suas propriedades ?ticas, mas no caso das flavanonas n?o existem trabalhos relatados na literatura. Portanto, no presente trabalho o objetivo foi sintetizar uma s?rie de novas difluoroboro-flavanonas e estudar suas propriedades foto-f?sicas por diferentes t?cnicas de emiss?o como fluoresc?ncia estacionaria e fluoresc?ncia resolvida no tempo. O mecanismo de s?ntese empregado foi baseado na rea??o de condensa??o de Claisen para a obten??o de ?-dicetonas substitu?das e subsequentemente as flavanonas, a partir das quais foram obtidas as difluoroboro-flavanonas in?ditas, por meio da rea??o de complexa??o entre as flavanonas sintetizadas e o BF3.Et2O. Os estudos foto-f?sicos por meio das t?cnicas de absor??o na regi?o do UV-vis?vel, emiss?o por fluoresc?ncia estacionaria e fluoresc?ncia resolvida no tempo permitiram obter os valores de rendimento qu?ntico em solu??o, sendo o composto 57 o mais fluorescente na presen?a de CHCl3 como solvente, ?=0,75012. Al?m disso, cada mol?cula analisada apresentou s? um tempo de decaimento em cada solvente o que significa que na solu??o a emiss?o observada foi devida somente a um processo de decaimento e, portanto, s? uma esp?cie ? respons?vel pela emiss?o de fluoresc?ncia. Foram feitos tamb?m os c?lculos experimentais dos n?veis de energia HOMO e LUMO por meio da t?cnica de voltametria c?clica, sendo os valores similares entre os compostos obtidos e estudados.Difluoroboro ?-dicetonate complexes are highly luminescent with extensive properties such as fluorescence both in solution and in solid state and high molar extinction coefficients. Due to the rich optical properties, these compounds show wide applications in various areas within synthetic chemistry and organic electronics such as in self-assembly and applications in biosensors, bio-imaging and optoelectronic devices. The easy and fast synthesis process makes the development of these ?-dicetonatederived compounds and their optical properties even more attractive, but in the case of flavanones there are no reported works in the literature. Therefore, in the present work the aim is to synthesize a range of molecules and study their photo-physical properties by different emission techniques such as stationary fluorescence and time-resolved fluorescence. The mechanism of synthesis applied is based on a Baker?Venkataraman reaction in order to obtain substituted diketones which were subsequently reacted with aldehydes to afford the proposed flavanones. The complexation was achieved from the optimized reaction between the synthesized flavanones and BF3. Et2O. The photophysical studies were carried out using UV-visible absorption, emission by stationary fluorescence and fluorescence resolved in time techniques which allowed us to determine the quantum yield (?) in solution. Compound 57 was the most fluorescent in the presence of CHCl3 as a solvent (?=0,75012 and 4,78?0,03 ns as decay time). In addition, each molecule analyzed presented only one decay time in each solvent which means that in the solution the observed emission is due to a single decay process and therefore only one species is responsible for the emission of fluorescence. The experimental calculations of the HOMO and LUMO energy levels were also performed by means of the cyclic voltametry technique, being all the values similar among the molecules under study

Synthesis, photophysical and electrochemical properties of novel and highly fluorescent difluoroboron flavanone beta-diketonate complexes

Difluoroboron β-diketonates complexes are highly luminescent with extensive properties such as their fluorescence both in solution and in solid state and their high molar extinction coefficients. Due to their rich optical properties, these compounds have been studied for their applications in organic electronics such as in self-assembly and applications in biosensors, bio-imaging and optoelectronic devices. The easy and fast synthesis of difluoroboron β-diketonate (BF2dbm) complexes makes their applications even more attractive. Although many different types of difluoroboron β-diketonates complexes have been studied, the cyclic flavanone analogues of these compounds have never been reported in the literature. Therefore, the present work aims to synthesize difluouroboron flavanone β-diketonate complexes, study their photophysical and electrochemical properties and assess their suitability for applications in optoelectronic devices. The synthesis was based on a Baker-Venkataraman reaction which initially provided substituted diketones, which were subsequently reacted with aldehydes to afford the proposed flavanones. The complexation was achieved by reacting flavanones and BF3·Et2O and in total 9 novel compounds were obtained. A representative difluoroboron flavanone complex was subjected to single crystal X-ray diffraction to unequivocally confirm the chemical structure. A stability study indicated only partial degradation of these compounds over a few days in a protic solvent at elevated temperatures. Photophysical studies revealed that the substituent groups and the solvent media significantly influence the electrochemical and photophysical properties of the final compounds, especially the molar absorption coefficient, fluorescence quantum yields, and the band gap. Moreover, the compounds exhibited a single excited-state lifetime in all studied solvents. Computational studies were employed to evaluate ground and excited state properties and carry out DFT and TDDFT level analysis. These studies clarify the role of each state in the experimental absorption spectra as well as the effect of the solvent

CCDC 1996094: Experimental Crystal Structure Determination

Related Article: Elida Betania Ariza Paez, Sergio Curcio, Natália P. Neme, Matheus J. S. Matos, Rodrigo S. Correa, Fabio Junio Pereira, Flaviane Francisco Hilário, Thiago Cazati, Jason Guy Taylor|2020|New J.Chem.|44|14615|doi:10.1039/D0NJ03525