Document Detail

Structural Refinement of Ladder-Type Perylenediimide Dimers: A Classical Tale of Conformational Dynamics.
MedLine Citation:
PMID:  23941640     Owner:  NLM     Status:  Publisher    
We have synthesized and thoroughly characterized two representative ladder-type acetylene-bridged perylenediimide dimers bearing long alkyl chain solubilizing groups, bis[1-ethynyl-N,N'-bis(1-hexylheptyl)-perylene-3,4:9,10-tetracarboxylic diimide] ([PDICC]2, 1) and 1,1'-ethynyl-bis[N,N'-bis(1-hexylheptyl)-perylene-3,4:9,10-tetracarboxylic diimide] ([PDI]2CC, 2). In these dimeric PDI molecules, NMR-based structural characterization became non-trivial as severe 1H spectral broadening and greater than expected numbers of observed 13C resonances substantially complicated the interpretation of traditional 1-D spectra. However, rational two-dimensional NMR approaches, based on both homo- and heteronuclear couplings (1H-1H COSY; 1H-13C HSQC), in conjunction with high level structural DFT calculations (GIAO/B3LYP/6-31G(d,p)/PCM, chloroform), were readily applied to these structures producing well-defined analytical characterization and the associated methodology is described in detail. Furthermore, based on dynamic NMR experiments, both 1 and 2 were found to exist in a perylene-centered conformational dynamic equilibrium (free energy of activation = 13-17 kcal/mol) which primarily caused the observed ambiguities in conventional 1-D spectra.
Mykhaylo Myahkostupov; Valentina Prusakova; Daniel G Oblinsky; Gregory D Scholes; Phil Castellano
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2013-8-13
Journal Detail:
Title:  The Journal of organic chemistry     Volume:  -     ISSN:  1520-6904     ISO Abbreviation:  J. Org. Chem.     Publication Date:  2013 Aug 
Date Detail:
Created Date:  2013-8-14     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  2985193R     Medline TA:  J Org Chem     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
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