2. Structure-Property Relationships of pi-Electron Systems

Functional pi-electron systems account for numerous unique properties and chemical phenomena as exemplified by organic semiconductors, photovoltaic devices, crystal structure of organic molecules and gas storage materials. Interactions of pi-conjugated systems also contribute importantly to the stability of DNA and to the ability of proteins to bind drugs. Understanding the peculiar electronic properties associated with pi-resonance and pi-pi stacking interactions is thus crucial to the elaboration of novel molecules with predefined properties. In this context, the development of quantum chemical methods enabling the direct probing and tuning of electron delocalization effects on materials/(bio)molecules properties represent an exceptional prospect. 

LCMD has proposed schemes to compute the molecular properties of specific resonance structures (i.e. Lewis), in which conjugative interactions are disabled by using a block-Localized wavefunction. Jerome has also proposed a computational criterion, LOLIPOP, which detects pi-conjugated framework exhibiting enhanced pi-stacking ability. In collaboration with LCS, the scheme has been successfully used to identify improved caffeine fluoresent sensors.

For a proof a principle example, check here Stephan and Daniel’s article in Angew. Chem. Int. Ed. (ACIE2009).

The scheme has been used for solving a long-standing mystery of organic chemistry, check in the special emerging investigator issue of Chemical Communcations (Chem.Commun.2011). 

For a recent applications on molecular scalar fields, see PCCP2011.

 

Together with Yirong Mo (Western Michigain U.), we proposed a scheme that combines the BLW energy decomposition analysis with Stephan’s density-dependent correction (dDsC). Such a scheme (JPCA2011) provides an insightful energy decomposition analysis including the separation between polarization and CT in complexes for which vDW interactions are also of key importance (e.g. TTF-TCNQ in JCTC2012).