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Intraparticle Charge Delocalization of Carbene-Functionalized Ruthenium Nanoparticles Manipulated by Selective Ion Binding.
MedLine Citation:
PMID:  21894955     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Olefin metathesis reactions of carbene-stabilized ruthenium nanoparticles were exploited for the incorporation of multiple functional moieties onto the nanoparticle surface. When the nanoparticles were co-functionalized with 4-vinylbenzo-18-crown-6 and 1-vinylpyrene, the resulting particles exhibited fluorescence characteristics that were consistent with dimeric pyrene with a conjugated chemical bridge, with three peaks observed in the emission spectra at 391 nm, 410 nm, and 485 nm. The behaviors were ascribed to intraparticle charge delocalization between the pyrene moieties afforded by the conjugated Ru=carbene interfacial linkages. Notably, upon the binding of metal ions into the crown ether cavity, the emission intensity of the nanoparticle fluorescence was found to diminish at 485 nm and concurrently increase at 391 and 410 nm rather markedly, with the most significant effects observed with K+ ions. This was accounted for by the selective binding of 18-crown-6 to potassium ions, where the positively charged ions led to polarization of the nanoparticle core electrons that was facililated by the conjugated linkage to the metal surface and hence impeded intraparticle charge delocalization. Control experiments with a pyrene-crown ether conjugate (2) and with ruthenium nanoparticles co-functionalized with 4-vinylbenzo-18-crown-6 and 1-allylpyrene suggested that the through-bond pathway played a predominant role in the manipulation of intraparticle electronic communication whereas the contributions from simple electrostatic interactions (i.e., through-space pathway) were minimal.
Authors:
Xiongwu Kang; Wei Chen; Nathaniel B Zuckerman; Joseph P Konopelski; Shaowei Chen
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-9-6
Journal Detail:
Title:  Langmuir : the ACS journal of surfaces and colloids     Volume:  -     ISSN:  1520-5827     ISO Abbreviation:  -     Publication Date:  2011 Sep 
Date Detail:
Created Date:  2011-9-7     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9882736     Medline TA:  Langmuir     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
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