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Titolo:
Synthesis, structural characterization, solvatochromism, and electrochemistry of tetra-osium carbonyl clusters containing azo-ligands
Autore:
Li, Y; Lin, ZY; Wong, WT;
Indirizzi:
Univ Hong Kong, Dept Chem, Hong Kong, Hong Kong, Peoples R China Univ HongKong Hong Kong Hong Kong Peoples R China Kong, Peoples R China Univ Sci & Technol, Dept Chem, Hong Kong, Hong Kong, Peoples R China Univ Sci & Technol Hong Kong Hong Kong Peoples R China , Peoples R China
Titolo Testata:
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
fascicolo: 12, , anno: 2001,
pagine: 3163 - 3173
SICI:
1434-1948(200112):12<3163:SSCSAE>2.0.ZU;2-Q
Fonte:
ISI
Lingua:
ENG
Soggetto:
ELECTRONIC INTERACTIONS; CRYSTAL-STRUCTURES; MOLECULAR-STRUCTURES; DINUCLEAR COMPLEXES; MULTICLUSTER ARRAYS; BRIDGING LIGANDS; N=N BOND; CLEAVAGE; RUTHENIUM; REDUCTION;
Keywords:
electrochemistry; solvatochromism; azo-compounds; osmium; cluster compounds;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
59
Recensione:
Indirizzi per estratti:
Indirizzo: Wong, WT Univ Hong Kong, Dept Chem, Pokfulam Rd, Hong Kong, Hong Kong, Peoples R China Univ Hong Kong Pokfulam Rd Hong Kong Hong Kong Peoples R China a
Citazione:
Y. Li et al., "Synthesis, structural characterization, solvatochromism, and electrochemistry of tetra-osium carbonyl clusters containing azo-ligands", EUR J INORG, (12), 2001, pp. 3163-3173

Abstract

The reaction of [Os-4(p-H)(4)(CO)(12)] with 4-(2-pyridylazo)-N,N-dimethylaniline (PNNDA) in dichloromethane afforded the new clusters [Os-4(p-H)(4)(CO)(11)[NC5H4(N=N)C6H4NMe2}] (1) and [Os-4(mu -H)(4)(CO)(10)(eta (2)-NC5H4(N=N)C6H4NMe2)] (2) 34% and 15% yields, respectively. Upon heating in tolueneunder reflux, compound 1 converted into 2 in 80% yield. The MLCT transition of compound 2 shows strong solvent dependency, displaying unusually largepositive solvatochromism in different organic solvents. Treatment of [Os4(pH)4(CO)12] with 2-(5-bromo-2-pyridylazo)-5-(diethylamino)phenol (Br-PADAP)in dichloromethane gives [Os-4(mu -H)(3)(CO)(10)[mu-eta (3)-Et2NC6H3(O)(N=N)C5NH3Br)] (3). The O-H bond activation is observed and the azo-ligand behaves as a five-electron donor. The clusters [Os-4(mu -H)(2)(CO)(10)[mu-eta (3)-NC5H4(N=N)C5H4N}] (4) and [Os-4(mu -H)(4)(CO)(10)[mu-eta (2)-NC5H4(N=N)C5H4N}](2) (5) were isolated from the reaction of [Os-4(mu -H)(4)(CO)(10)(NCMe)(2)] with 2,2'-azopyridine and 3,3'-azopyridine, respectively. In compound 4, both pyridine and azo nitrogen atoms were found to coordinate to thecluster core. Dehydrogenation was also observed in this compound. For compound 5, two tetra-osmium metal cores were connected by two azo ligands through their pyridyl nitrogen atoms to form a novel cyclic structure. The redox properties of the compounds described herein were investigated by means of cyclic voltammetry and controlled potential coulometry. Both compound 2 and 5 exhibit a reversible cathodic wave, which indicates that they undergo addition of one electron without significant structural changes. Furthermore, compound 5 displays an electronic interaction between two redox centers,the extra electrons are believed to delocalize throughout the cyclic structure.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 05/04/20 alle ore 03:57:24