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1. Collective Vibrational Strong Coupling Effects on Molecular Vibrational Relaxation and Energy Transfer: Numerical Insights via Cavity Molecular Dynamics Simulations

   Li, T.E. Li; Nitzan, A.; Subotnik, J.E. (May 2021, Angewandte Chemie)

   null (Ed.)

   We use classical cavity molecular dynamics simulations to investigate the effect of optical cavity environment on vibrational energy transfer and relaxation. For a small fraction of vibrationally hot CO2 molecules immersed in a liquid-phase CO2 thermal bath, in a cavity that supports a cavity mode in resonance with the CO asymmetric stretch vibration, forming collective vibrational strong coupling (VSC) and a cavity mode accelerates hot molecule relaxation. This acceleration stems from the fact that polaritons can be transiently excited during the nonequilibrium process, which facilitates intermolecular vibrational energy transfer. The VSC effects on these rates (i) resonantly depend on the cavity mode detuning, (ii) cooperatively depend on Rabi splitting, and (iii) collectively scale with the number of hot molecules. This behavior weakens with increasing cavity size (at constant molecular density), that is, constant Rabi splitting) but remains meaningful up to cavities containing 10^4 molecules 

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2. Tunable assembly of host–guest colloidal crystals

   https://doi.org/10.1039/D3SM00891F  

   Dwyer, Tobias; Moore, Timothy C; Anderson, Joshua A; Glotzer, Sharon C (September 2023, Soft Matter)

   Entropy compartmentalization provides new self-assembly routes to colloidal host–guest (HG) struc- tures. Leveraging host particle shape to drive the assembly of HG structures has only recently been proposed and demonstrated. However, the extent to which the guest particles can dictate the structure of the porous network of host particles has not been explored. In this work, by modifying only the guest shape, we show athermal, binary mixtures of star-shaped host particles and convex polygon-shaped guest particles assemble as many as five distinct crystal structures, including rotator and discrete rotator guest crystals, two homoporous host crystals, and one heteroporous host crystal. Edge-to-edge alignment of neighboring stars results in the formation of three distinct pore motifs, whose preferential formation is controlled by the size and shape of the guest particles. Finally, we confirm, via free volume calculations, that assembly is driven by entropy compartmentalization, where the hosts and guests contribute differently to the free energy of the system; free volume calculations also explain differences in assembly based on guest shape. These results provide guest design rules for assembling colloidal HG structures, especially on surfaces and interfaces. 

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3. Manipulating nonadiabatic conical intersection dynamics by optical cavities

   https://doi.org/10.1039/C9SC04992D  

   Gu, Bing; Mukamel, Shaul (February 2020, Chemical Science)

   Optical cavities hold great promise to manipulate and control the photochemistry of molecules. We demonstrate how molecular photochemical processes can be manipulated by strong light–matter coupling. For a molecule with an inherent conical intersection, optical cavities can induce significant changes in the nonadiabatic dynamics by either splitting the pristine conical intersections into two novel polaritonic conical intersections or by creating light-induced avoided crossings in the polaritonic surfaces. This is demonstrated by exact real-time quantum dynamics simulations of a three-state two-mode model of pyrazine strongly coupled to a single cavity photon mode. We further explore the effects of external environments through dissipative polaritonic dynamics computed using the hierarchical equation of motion method. We find that cavity-controlled photochemistry can be immune to external environments. We also demonstrate that the polariton-induced changes in the dynamics can be monitored by transient absorption spectroscopy. 

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4. Polariton ring currents and circular dichroism of Mg-porphyrin in a chiral cavity

   https://doi.org/10.1039/D1SC04341B  

   Sun, Shichao; Gu, Bing; Mukamel, Shaul (January 2022, Chemical Science)

   By placing Mg-porphyrin molecules in a chiral optical cavity, time reversal symmetry is broken, and polariton ring currents can be generated with linearly polarized light, resulting in a circular dichroism signal. Since the electronic state degeneracy in the molecule is lifted by the formation of chiral polaritons, this signal is one order of magnitude stronger than the bare molecule signal induced by circularly polarized light. Enantiomer-selective photochemical processes in chiral optical cavities is an intriguing future possibility. 

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5. Customizable molecular recognition: advancements in design, synthesis, and application of molecularly imprinted polymers

   https://doi.org/10.1039/D1PY01472B  

   Reville, Erinn K.; Sylvester, Elizabeth H.; Benware, Sarah J.; Negi, Shreeya S.; Berda, Erik B. (June 2022, Polymer Chemistry)

   Molecularly imprinted polymers (MIPs) are where the complexity of receptor proteins meets the tunability of synthetic research. Receptor proteins, such as enzymes or antibodies, have functional cavities that act as docking platforms by recognizing and binding to complementary ligands. Once bound, a receptor–ligand complex may generate any multitude of cellular responses, including the regulation, uptake, and/or release of certain hormones, neurotransmitters, inorganic minerals, antigens, enzymes, and other molecules within an organism. Just like receptor proteins, MIPs are polymers with carefully selected functional groups that are spacially arranged to recognize target molecules. MIPs are generated by templating a functionalized polymer with a molecule, leaving a cavity that is complementary to the molecule upon removal. That cavity then has an affinity for the molecule that was templeted for later rebinding. The aim of MIP research is to recognize a desired target molecule with the precision of receptor proteins, and to maintain specificity and sensitivity towards the target molecule while tailoring functional properties for advanced applications. Resarchers are far from perfecting the delicate intricacy of mimicking such elegant biological processes, and improvements in all areas of MIP synthesis remain a vibrant and active topic. Various methods explored to synthesize MIPs with impressive recognition capabilities towards target molecules and the recent applications of MIPs are found herein. This review aims to dissect the synthetic steps required to generate MIPs, with emphasis on the more recent routes utilized and overall application advances. 

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