Document Detail

Emissive Osmium(II) Complexes Supported by N-Heterocyclic Carbene-based C(∧)C(∧)C-Pincer Ligands and Aromatic Diimines.
MedLine Citation:
PMID:  22873818     Owner:  NLM     Status:  Publisher    
Osmium(II) complexes containing N-heterocyclic carbene (NHC)-based pincer ligand 1,3-bis(1-methylimidazolin-2-ylidene)phenyl anion (C(1)(∧)C(∧)C(1)) or 1,3-bis(3-methylbenzimidazolin-2-ylidene)phenyl anion (C(2)(∧)C(∧)C(2)) and aromatic diimine (2,2'-bipyridine (bpy), 1,10-phenanthroline (phen), or 4,4'-diphenyl-2,2'-bipyridine (Ph(2)bpy)) in the form of [Os(C(∧)C(∧)C)(N(∧)N)(CO)](+) have been prepared. Crystal structures for these complexes show that the Os-C(NHC) bonds are essentially single (Os-C(NHC) distances = 2.079(5)-2.103(7) Å). Spectroscopic comparisons and time-dependent density functional theory (TD-DFT) calculations suggest that the lowest-energy electronic transition associated with these complexes (λ(max) = 493-536 nm, ε(max) = (5-10) × 10(3) dm(3) mol(-1) cm(-1), solvent = CH(3)CN) originate from a d(π)(Os(II)) → π*(N(∧)N) metal-to-ligand charge transfer transition, where the d(π)(Os(II)) and π*(N(∧)N) levels contain significant contribution from the C(∧)C(∧)C ligands. All these complexes are emissive in the red-spectral region (674-731 nm) with quantum yields of 10(-4)-10(-2) and emission lifetimes of around 1-6 μs. Transient absorption spectroscopy and spectroelectrochemical measurements have also been used to probe the nature of the emissive excited-states. Overall, this joint experimental and theoretical investigation reveals that the C(∧)C(∧)C ligands can be used to modulate the photophysical properties of a [Os(N(∧)N)] core via the formation of the hybrid [Os + C(∧)C(∧)C] frontier orbitals.
Lai-Hon Chung; Siu-Chung Chan; Wing-Chun Lee; Chun-Yuen Wong
Related Documents :
17566918 - Two new alkaloidal glycosides from the root bark of ailanthus altissima.
22079438 - What makes a simple partial seizure complex?
16599268 - Sesquiterpenes with various carbon skeletons from ligularia virgaurea spp. oligocephala.
21583998 - Methyl 5-bromo-2-[meth-yl(methyl-sulfon-yl)amino]benzoate.
20831208 - Fe(ii)-fe(iii)-bearing phases as a mineralogical control on the heterogeneity of arseni...
15041288 - Identification and behavior of reaction products formed by chlorination of ethynylestra...
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-8-8
Journal Detail:
Title:  Inorganic chemistry     Volume:  -     ISSN:  1520-510X     ISO Abbreviation:  Inorg Chem     Publication Date:  2012 Aug 
Date Detail:
Created Date:  2012-8-9     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0366543     Medline TA:  Inorg Chem     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Department of Biology and Chemistry, City University of Hong Kong , Tat Chee Avenue, Kowloon, Hong Kong SAR, People's Republic of China.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

Previous Document:  Mass spectrometric method for determining the uronic acid epimerization in heparan sulfate disacchar...
Next Document:  Ondansetron and Granisetron Binding Orientation in the 5-HT3 Receptor Determined by Unnatural Amino ...