DFT calculations: Bridged-azo working with visible light

The photochemical trans → cis and thermal cis → trans isomerization pathways of azobenzo-13-crown ether: A computational study on a strained cyclic azobenzene system

The isomerization of azobenzo-13-crown ether can be expected to be hindered due to the polyoxyethylene linkage connecting the 2,2'-positions of azobenzene. The mixed reference spin-flip time-dependent density functional theory results reveal that the planar and rotational minima of the first photo-excited singlet state (S1) of the trans-isomer pass through a barrier (2.5-5.0 kcal/mol) as it goes toward the torsional conical intersection (S0/S1) geometry ( Collapse

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Dilawar Singh Sisodiya Department of Chemistry, Birla Institute of Technology and Science (BITS), Pilani, K. K. Birla Goa Campus, Zuarinagar, India
Anjan Chattopadhyay Department of Chemistry, Birla Institute of Technology and Science (BITS), Pilani, K. K. Birla Goa Campus, Zuarinagar, India

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Unexplored Isomerization Pathways of Azobis(benzo-15-crown-5): Computational Studies on a Butterfly Crown Ether

Computational studies on trans → cis and cis → trans isomerizations of photoresponsive azobis(benzo-15-crown-5) have been reported in this work. The photoexcited ππ* state (S2) of the trans isomer relaxes through the planar S2 minimum and the planar S2/S1 conical intersection (both situated around 9 kcal/mol below the vertically excited S2 state) arising along the N═N stretching coordinate. The nπ* state (S1) of this isomer has both planar and rotated (clockwise and anticlockwise) minima, which may lead to a torsional conical intersection (S0/S1) geometry having a Collapse

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Affiliation(s)

Dilawar Singh Sisodiya Department of Chemistry, Birla Institute of Technology and Science (BITS), Pilani, K.K. Birla Goa Campus, Zuarinagar 403726, India
Sk Musharaf Ali Chemical Engineering Division, Bhabha Atomic Research Centre (BARC), Mumbai 400085, India
Anjan Chattopadhyay Department of Chemistry, Birla Institute of Technology and Science (BITS), Pilani, K.K. Birla Goa Campus, Zuarinagar 403726, India

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One-Pot Difunctionalization of Aryldiazonium Salts for Synthesis of para-Azophenols

A novel difunctionalization of aryldiazonium salts was realized for the one-step generation of symmetric and asymmetric p-azophenols. This approach is proceeded by the sequentially regioselective aromatic C-O and C-N bond construction under mild reaction conditions, unlocking a new reaction strategy to facilitate the synthesis of p-azophenols.