<h3>Title</h3>
<p><span style="color: #0000ff;">Organic Photoredox catalysis inside Supramolecular Cavities</span></p>
<p><strong><span style="text-decoration: underline;">Abstract</span> :</strong></p>
<p>Natural enzymes carry out organic transformations efficiently via pre-organizing substrates inside hydrophobic cavities to achieve selectivity and specificity during reaction turnover. Chemists have mimicked the enzymes by creating supramolecular cavities which can serve as active sites for catalysis. Recently it has been demonstrated that organic C-H activation reactions can be carried out inside a metal-based cationic water-soluble nanocage with visible light activation. To completely report a metal-free photoactivation scheme for carrying out catalysis, we planned to synthesize an all-organic cationic nanocage ExBox<sup>4+</sup>. By incarcerating a series of polyaromatic hydrocarbon (PAH) guests inside the ExBox<sup>4+</sup> we were able to generate host-guest CT states that enabled a completely new metal-free C-H activation chemistry in acetonitrile under ambient conditions. The characterization of the host-guest complexes with PAHs of different sizes and their photoexcited dynamics for C-H bond activation using transient absorption spectroscopy will be discussed in the first part of the talk.            </p>
<p>The second part of my talk will be dedicated to the formation of C-C bonds through sp C-H activation in aqueous confinement.  A Pd-based hybrid metal-organic supramolecular cavity was used in this case to encapsulate the guest phenyl acetylene. Upon visible light photoirradiation we found dimer products which indicated C-C bond formation after proton-coupled electron transfer steps. Characterization of photoproducts via GCMS and the mechanistic insights towards the formation of coupling products will be demonstrated using time-resolved absorption measurements.</p>