One-Pot and Step-by-Step N-Assisted C(Ph)-H Activation in 2-(4-Bromophenyl)imidazol[1,2-a]pyridine: Synthesis of a New C,N-Cyclometalated Compound [{Pt(C(boolean AND)N)(mu-Cl)}(2)] as Precursor of Luminescent Platinum(II) Compounds

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dc.contributor.authorFornies, J.en
dc.contributor.authorSicilia, V.en
dc.contributor.authorLarraz, C.en
dc.contributor.authorCamerano, J. A.en
dc.contributor.authorMartin, A.en
dc.contributor.authorCasas, J. M.en
dc.contributor.authorTsipis, A. C.en
dc.date.accessioned2015-11-24T16:43:20Z
dc.date.available2015-11-24T16:43:20Z
dc.identifier.issn0276-7333-
dc.identifier.urihttps://olympias.lib.uoi.gr/jspui/handle/123456789/8686
dc.rightsDefault Licence-
dc.subjectmetal-carbon bondsen
dc.subjectcyclometalated pt(ii) complexesen
dc.subject5-membered ring compoundsen
dc.subjectray crystal-structureen
dc.subjectstructural-characterizationen
dc.subjectiridium(iii) complexesen
dc.subjectspectroscopic propertiesen
dc.subjectphotophysical propertiesen
dc.subjectelectronic spectroscopyen
dc.subjectisocyanide ligandsen
dc.titleOne-Pot and Step-by-Step N-Assisted C(Ph)-H Activation in 2-(4-Bromophenyl)imidazol[1,2-a]pyridine: Synthesis of a New C,N-Cyclometalated Compound [{Pt(C(boolean AND)N)(mu-Cl)}(2)] as Precursor of Luminescent Platinum(II) Compoundsen
heal.abstractThe activation of a C(ph)-H bond in the phenyl ring of 2-(4-bromophenyl)imidazol[1,2-a]pyridine (HC(boolean AND)N) by [{Pt(eta(3)-C(4)H(7))(mu-Cl)}(2)](eta(3)-C(4)H(7) = eta(3)-2-methylallyl) renders the new cyclometalated complex [Ppt(C(boolean AND)N)(mu-Cl)}(2)] (2) with high yield and selectivity. Complex 2 can be achieved directly in a one-pot reaction or step by step through the intermediate [Pt(eta(3)-C(4)H(7))Cl(HC(boolean AND)N-kappa N)] (1). Compound I could be isolated and fully characterized. The X-ray structure shows the coordination of HCA(boolean AND)N through only the N and the existence of a weak Pt center dot center dot center dot H-C hydrogen bridging bond (Pt center dot center dot center dot H1 = 2.78 angstrom, Pt center dot center dot center dot Cl = 3.365(3) angstrom, Pt-Hl-Cl = 120.9 degrees). Hence, the formation of this intermediate could be considered the first step in the cyclometalation process. The mononuclear complexes [PtCl(C(boolean AND)N)L] (L = tht (3), PPh(3) (4), CN-Xyl (5), CN-(t)Bu (6)) were obtained by cleavage of the bridging system in [{Pt(C(boolean AND)N)mu-Cl)}(2)] (2) by the neutral ligands, L. The resulting geometry (trans C, Cl) is that expected from the electronic preferences, taking into account the degree of transphobia (T) of pairs of trans ligands, T[C(C(boolean AND)N)/L(CI)] < T[C(C(boolean AND)N)/L(S, P, C)]. Complexes [PtCI(C(boolean AND)N)L] (L = CN-Xyl (5), CN-(t)Bu (6)) containing two strong-field ligands, a C(C)boolean AND N sigma-abonded and an isocyanide ligand, are luminescent. TD-DFT calculations were performed for the singlet ground state, S(0), as well as for the first triplet excited state of 6 in both the gas phase and solution. Calculations indicate that the lowest-lying absorption involves mainly (1)IL (C(boolean AND)N) mixed with a small contribution of (1)MLCT/(1)L'LCT (L = C(boolean AND)N; L' = Cl) transitions. Complex 5 exhibits "luminescent thermochromism" in the solid state; at 77 K it shows a green phosphorescence band assigned to (3)IL transitions located on the C(boolean AND)N group of monomer species, while at 298 K an orange-red emission is observed, being tentatively assigned to excited states of emissive aggregates ((3)MMLCT/(3)pi-pi*). However complex 6 shows phosphorescence only at 77 K both in Solution and in the solid state with the emissions arising from (3)IL and 3L'MLCT excited states of monomer species.en
heal.accesscampus-
heal.fullTextAvailabilityTRUE-
heal.identifier.primaryDoi 10.1021/Om901032v-
heal.identifier.secondary<Go to ISI>://000275410300013-
heal.identifier.secondaryhttp://pubs.acs.org/doi/abs/10.1021/om901032v-
heal.journalNameOrganometallicsen
heal.journalTypepeer reviewed-
heal.languageen-
heal.publicationDate2010-
heal.recordProviderΠανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείαςel
heal.typejournalArticle-
heal.type.elΆρθρο Περιοδικούel
heal.type.enJournal articleen

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