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SUMMARY:Highly Polar Supramolecular Species with Enhanced IR Activity - Pr
 ofessor Fedor Naumkin\, University of Ontario
DTSTART:20190515T131500Z
DTEND:20190515T141500Z
UID:TALK115180@talks.cam.ac.uk
CONTACT:Lisa Masters
DESCRIPTION:Highly polar molecular systems are in need for many important 
 practical applications based on light-matter interactions\, e.g. solar ene
 rgy utilization.\n   Novel insertion complexes of polar molecules non-cova
 lently trapped between alkali-halide (MX) counter-ions are compared to non
 -polar-based counterparts [1-3]. The M-molecule-X systems can exhibit from
  a metastability to a stability by up to 1 eV relative to molecule + MX. T
 he polar-molecule insertion complexes can be even more strongly bound than
  the common dipole-dipole MX-molecule conformers and separated from those 
 by significant energy barriers\, thus being thermodynamically stable speci
 es with very large dipoles of up to > 25 D.\n   Interesting features inclu
 de the nonobvious contributions of the molecule polarity to the system sta
 bility and dipole moment\, the cooperative non-additivity of pair interact
 ions\, molecule reshaping and linking by framing ion-pairs. The latter is 
 demonstrated by a (M-molecule-X)2 dimer\, stable to dissociation and extre
 mely polar at about 50 D.\n   For the corresponding (M-molecule-X)– anio
 ns\, relative stabilities of various conformers and barriers between them 
 vary significantly relative to the neutral counterparts. Feasible pathways
  for experimental production of the M-molecule-X species are analyzed usin
 g the energy profiles for the neutral and anionic systems.\n   Due to neut
 ralization of the M-X charge-transfer in the excited triplet state\, these
  complexes represent unique spin-controlled dipole-switch molecular system
 s with a large dipole reversibly turned off or even inverted by the spin s
 tate\, potentially allowing various spin/optoelectronic applications. The 
 IR spectra are predicted to considerably vary and sensitively indicate the
  formation of both the M-molecule-X and MX-molecule conformers\, with inte
 nsities up to an order of magnitude higher in the complexes\, facilitating
  their reliable detection and differentiation in experiments. The above in
 dicates possible ways of adding polarity (via attached ion-pairs) to nonpo
 lar molecules and thus of their efficient experimental detection and chara
 cterization. The so increased attraction could promote molecular self-asse
 mbly and chemical reactions as well. While metastable systems suggest poss
 ible applications for high-capacity energy storage. \n\n[1]   F. Y. Naumki
 n\, J. Phys. Chem. A 121\, 4545 (2017). \n[2]   S. Kerr\, F. Y. Naumkin\, 
 New J. Chem.\, 41\, 13576 (2017).\n[3]   B. Cochrane\, F. Y. Naumkin\, Che
 m. Phys. Lett. 643\, 137 (2016).\n
LOCATION:Department of Chemistry\, Cambridge\, Unilever lecture theatre
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