Synthesis and Spectroscopic Investigation of Diketopyrrolopyrrole - Spiropyran Dyad for Fluorescent Switch Application

Abstract

We report the synthesis and characterization of a new fluorescent dyad SP-DPP-SP(9) via efficient palladium-catalyzed Sonogashira coupling of prop-2-yn-1-yl 3-(3',3'dimethyl-6-nitrospiro[chromene-2,2'-indolin]-1'-yl)propanoatespiropyran, SP(8), a well known photochromic accepter, with 3,6-bis(5-bromothiophen-2-yl)-2,5-bis((R)-2-ethylhexyl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione, DPP(4), a highly fluorescent donor. Under visible light exposure the SP unit is in a closed hydrophobic form, whereas under UV irradiation it converts to a polar, hydrophilic open form named Merocyanine (MC), which is responsible for functioning of photo-switch application. The photochemistry pertaining to fluorescence switch, 'on/off' behaviour, of model dyad SP-DPP-SP(9) is experimentally analyzed in solution as well as in solid state in polymer matrices by photoluminescence(PL) and absorption spectroscopy. After absorption of UV light the spiropyran unit of the dyad under goes the rupture of the spiro C-O bond leading to the formation of MC. The absorption band of MC fairly overlaps to the fluorescence of DPP unit resulting quenching of fluorescence via fluorescence resonance energy transfer from exited DPP unit to ground state MC. In contrary, the fluorescence of DPP is fully regained upon transformation of MC to SP by exposure to visible light or thermal stimuli. Hence, the fluorescence intensity of dyad 9 is regulated by reversible conversion among the two states of the photochromic spiropyran units and the fluorescence resonance energy transfer (FRET) between the MC form of SP and the DPP unit. Conversely, these scrutiny of the experiment express that the design of dyad 9 is viable as efficient fluorescent switch molecule in many probable commercial applications, such as, logic gates and photonic and optical communications.

Design and Crystal Structures of Two New Compounds Fused with 3,4,5-Trimethoxybenzyl Group and 6,10-Dioxaspiro Group

“…Packing arrangement in the unit cell of J1 and J2 are displayed in Figure 2, respectively. 128.22 (15) 109.48(13) C(10)-C(12)-C (11) 114.83 (14) 113.71(15) C(13)-C(12)-C (11) 116.91 (14) 112.53(13) As can be seen from Figure 1, two compounds both comprise the 3,4,5-trimethoxybenzyl group and the dioxaspiro group. From the bond length data, the C10-C12 bond length of 1.535(2) Å (J2) is longer that of 1.359(4) (J1), which indicates that the 3,4,5-trimethoxybenzyl group connects with the dioxaspiro group by the central C(10) atoms via double bond (J1) and single bond (J2), respectively.…”

“…Spiro-thiazine derivatives act as antimycobacterial activity [6]. Recently, spiro compounds have also drawn much attention due to diverse applications in organic functional materials such as circularly polarized luminescence (CPL) materials [7], a new rhodamine-based chemosensor [8], organic light emitting diodes (OLEDs) [9], a high-performance electrophosphorescent device [10], a fluorescent switch [11], optical data storage [12], and so on.…”

Crystal structure of 8-(3,4-dimethylbenzylidene)-6,10-dioxaspiro[4.5]decane-7,9-dione, C17H18O4

“…Spiro compounds and their derivatives have been extensively studied due to their diverse biological application in antitumor [5], cytotoxic [6] antimicrobial [7], antioxidant [8], antineuroinflammatory [9] and antineoplastic [10]. In recent years, application of spiro compounds in optical fields such as organic semiconductor [11], fluorescent switches [12] and deep-blue emitting materials [13] has also received much attention. A large number of spiro compounds were synthesized for ten years [14][15][16][17][18].…”

The crystal structure of 3-cyclohexyl-1,5-dioxaspiro[5.5]undecane-2,4-dione, C15H22O4

“…Recently, a great deal of oxaspirocyclic compounds were designed and synthesized because of their wide application in medicine [4,5], asymmetric catalysis [6], fluorescent probe [7], fluorescent switch [8], high-density jet fuels [9] and so on. During ten years, our group prepared many oxaspirocyclic compounds [10][11][12].…”