A molecular photoswitch based on an ‘axial-bonding’ type phosphorus(v) porphyrin

Abstract

Reversible isomerization of the two axial azobenzene subunits leads to modulation of the fluorescence due to the basal tetrapyrrolic chromophore in a new hexa-coordinated phosphorus(V) porphyrin 3, illustrating its utility as a molecular photoswitch.

Design, Synthesis, In Vitro Evaluation and Docking Studies of Pyrazole‐Thiazole Hybrids as Antimicrobial and Antibiofilm Agents

“…The complete reaction conditions involved in the synthesis of titled compounds 4 a-l are illustrated in Scheme 1 and Scheme 2. The Vilsmeier-Haack formylation of hydrazone [31] achieved the key intermediate 1,3-disubstituted 4-functionalized pyrazole (1) [32,33] in 7-8 h, which in turn obtained by the condensation of 3-acetyl coumarin [34] and benzothiazole hydrazine in refluxing methanol in the presence of catalytic amount of glacial acetic acid for 4-5 h. [35,36] Further, the reaction of an aldehyde 1 with thiosemicarbazide 2 and various α-bromoketones 3 a-l by refluxing in ethanol for about 4-6 h in the presence of catalytic amount of glacial acetic acid leads to the target hybrid compounds 4 a-l in excellent yields (85-95%). Structural assignments have been made by FTIR, NMR ( 1 H and 13 C), mass spectrometry and CHN analysis data, which is summarized in supporting information.…”

Molecular Scale Conductance Photoswitching in Engineered Bacteriorhodopsin

“…6,10−13 The conformational changes in the receptor induce a charge separation that is coupled to proton transport 14 and involves a succession of charge displacements across the molecule resulting in a quantifiable photoelectric response. 7 Similarly, the photoresponse of a number of organic molecules, such as azobenzenes, spyropyrans and fulgides, triggers conformational changes that modulate the distance between electron donors and acceptors (for example, appended to the para position of phenylene rings in porphyrin−azobenzene−porphyrin 15 or azobenzene−porphyrin−azobenzene) 16 or between chromophore and electrodes in a proximal probe junction, to which, in most cases, current modulation of the reversible switching has been assigned. 17 Scanning probe techniques present a powerful means of elucidating molecular scale properties.…”

A novel zinc tetraphenylporphyrinate substituted in the axial position with one E-stilbazole: Synthesis, structure, and nonlinear optics

“…5. As a consequence, one can clearly see that the strong nonlinear refraction produces a valley-peak signature, with a pre-focal minimum followed by a post-focal maximum, corresponding to a selfdefocusing effect, which demonstrates a nonlinear refractive index with a positive sign [20]. It can be seen in Fig.…”

“…Upon excitation at 420 nm, ZnTPP displays emission bands at 593 and 645 nm that originate from the S1-S0 transition. Following excitation at the same wavelength, the emission intensity of the axial ligand L in ZnTPPL is decreased by 84% when compared to L, implying that the quenching process is probably due to the photo-induced energy transfer process from L to porphyrin [7,15,20]. Upon excitation at 420 nm, the axial ligand L is pumped into excited states, and then quenched significantly by the porphyrin core through strong intramolecular energy transfer.…”