Nano Archive

Tuning the Size and Optical Properties in Molecular Nano/Microcrystals: Manifestation of Hierarchical Interactions

Patra, A. and Hebalkar, N. and Sreedhar, B. and Sarkar, M. and Samanta, A. and Radhakrishnan, T. P. (2006) Tuning the Size and Optical Properties in Molecular Nano/Microcrystals: Manifestation of Hierarchical Interactions. Small, 2 (5). 650-659.

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Intermolecular interactions, such as hydrogen bonding, dipolar and van der Waals, occurring in molecular crystals cover a range of magnitudes. As the crystal evolves from a relatively softer state in the nanoscopic size regime to a harder one in the microcrystalline and bulk solid state, the impact of the hierarchy of intermolecular interactions can be expected to emerge in a progressive fashion. The strongest interactions alone would be manifested at small sizes; as the crystal grows, the effect of the weaker ones will be added on, with the bulk crystals exhibiting the cumulative impact of the different interactions. We demonstrate this phenomenon through investigations of the solution, colloid, and solid state of a novel zwitterionic molecule based on the diaminodicyanoquinodimethane framework. A reprecipitation-digestion protocol is developed for the fabrication of nano/microcrystals of varying sizes. Microscopic and spectroscopic characterizations reveal tuning of the size and optical properties of this material. The optical absorption of the colloidal particles evolves with size towards that of the bulk solid, the emission showing a steady enhancement of intensity. Crystallographic investigations coupled with semiempirical computations provide a viable model to describe the range of observations in terms of the gradual accumulation of hierarchical intermolecular interactions

Item Type:Article
Subjects:Material Science > Nanochemistry
Divisions:Faculty of Engineering, Science and Mathematics > School of Chemistry
ID Code:4463
Deposited By:JNCASR
Deposited On:02 Apr 2009 10:50
Last Modified:02 Apr 2009 10:50

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