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Article: Computational studies on the photophysical properties and NMR fluxionality of dinuclear platinum(II) a-frame alkynyl diphosphine complexes

TitleComputational studies on the photophysical properties and NMR fluxionality of dinuclear platinum(II) a-frame alkynyl diphosphine complexes
Authors
Issue Date2010
PublisherAmerican Chemical Society. The Journal's web site is located at http://pubs.acs.org/ic
Citation
Inorganic Chemistry, 2010, v. 49 n. 23, p. 10930-10939 How to Cite?
AbstractThe structural geometry, electronic structure, photophysical properties, and the fluxional behavior of a series of A-frame diplatinum alkynyl complexes, [Pt2(μ-dppm)2(μ-C≡CR)(C≡CR) 2]+ [R = tBu (1), C6H5 (2), C6H4Ph-p (3), C6H4Et-p (4), C6H4OMe-p (5); dppm = bis(diphenylphosphino)methane], have been studied by density functional theory (DFT) and time-dependent TD-DFT associated with conductor-like polarizable continuum model (CPCM) calculations. The results show that the Pt⋯Pt distance strongly depends on the binding mode of the alkynyl ligands. A significantly shorter Pt⋯Pt distance is found in the symmetrical form, in which the bridging alkynyl ligand is σ-bound to the two metal centers, than in the unsymmetrical form where the alkynyl ligand is σ-bound to one metal and π-bound to another. For the two structural forms in 1-5, both the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energy levels show a dependence on the nature of the substituents attached to the alkynyl ligand. The energies of the HOMO and LUMO are found to increase and decrease, respectively, from R = tBu to R = Ph and to R = C6H4Ph-p, because of the increase of the π- conjugation of the alkynyl ligand. On the basis of the TDDFT/CPCM calculations, the low-energy absorption band consists of two types of transitions, which are ligand-to-ligand charge-transfer (LLCT) [π(alkynyl) → σ*(dppm)]/metal-centered MC [dσ*(Pt2) → pσ(Pt2)] transitions as well as interligand π → π* transition from the terminal alkynyl ligands to the bridging alkynyl ligand mixed with metal-metal-to-ligand charge transfer MMLCT [dσ*(Pt2) → π*(bridging alkynyl)] transition. The latter transition is lower in energy than the former. The calculation also indicates that the emission for the complexes originates from the triplet interligand π(terminal alkynyls) → π*(bridging alkynyl)/MMLCT [dσ*(Pt2) → π*(bridging alkynyl)] excited state. In terms of the fluxional behavior, calculations have been performed to study the details of the mechanisms for the three fluxional processes, which are the σ,π-alkynyl exchange, the ring-flipping, and the bridging-to-terminal alkynyl exchange processes. © 2010 American Chemical Society.
Persistent Identifierhttp://hdl.handle.net/10722/133602
ISSN
2015 Impact Factor: 4.82
2015 SCImago Journal Rankings: 1.873
ISI Accession Number ID
Funding AgencyGrant Number
University of Hong Kong200905159002
URC
University Grants CommitteeAoE/P-03/08
Funding Information:

V.W.-W.Y. acknowledges support from The University of Hong Kong under the Distinguished Research Achievement Award Scheme and the URC Strategic Research Theme on Molecular Materials. This work has been supported by the University Grants Committee Areas of Excellence Scheme (AoE/P-03/08). W.H.L. acknowledges support from the URC Seed Funding for Basic Research from The University of Hong Kong (200905159002). We also thank the Computer Center at The University of Hong Kong for providing the computational resources.

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DC FieldValueLanguage
dc.contributor.authorLam, WHen_HK
dc.contributor.authorYam, VWWen_HK
dc.date.accessioned2011-05-24T02:11:37Z-
dc.date.available2011-05-24T02:11:37Z-
dc.date.issued2010en_HK
dc.identifier.citationInorganic Chemistry, 2010, v. 49 n. 23, p. 10930-10939en_HK
dc.identifier.issn0020-1669en_HK
dc.identifier.urihttp://hdl.handle.net/10722/133602-
dc.description.abstractThe structural geometry, electronic structure, photophysical properties, and the fluxional behavior of a series of A-frame diplatinum alkynyl complexes, [Pt2(μ-dppm)2(μ-C≡CR)(C≡CR) 2]+ [R = tBu (1), C6H5 (2), C6H4Ph-p (3), C6H4Et-p (4), C6H4OMe-p (5); dppm = bis(diphenylphosphino)methane], have been studied by density functional theory (DFT) and time-dependent TD-DFT associated with conductor-like polarizable continuum model (CPCM) calculations. The results show that the Pt⋯Pt distance strongly depends on the binding mode of the alkynyl ligands. A significantly shorter Pt⋯Pt distance is found in the symmetrical form, in which the bridging alkynyl ligand is σ-bound to the two metal centers, than in the unsymmetrical form where the alkynyl ligand is σ-bound to one metal and π-bound to another. For the two structural forms in 1-5, both the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energy levels show a dependence on the nature of the substituents attached to the alkynyl ligand. The energies of the HOMO and LUMO are found to increase and decrease, respectively, from R = tBu to R = Ph and to R = C6H4Ph-p, because of the increase of the π- conjugation of the alkynyl ligand. On the basis of the TDDFT/CPCM calculations, the low-energy absorption band consists of two types of transitions, which are ligand-to-ligand charge-transfer (LLCT) [π(alkynyl) → σ*(dppm)]/metal-centered MC [dσ*(Pt2) → pσ(Pt2)] transitions as well as interligand π → π* transition from the terminal alkynyl ligands to the bridging alkynyl ligand mixed with metal-metal-to-ligand charge transfer MMLCT [dσ*(Pt2) → π*(bridging alkynyl)] transition. The latter transition is lower in energy than the former. The calculation also indicates that the emission for the complexes originates from the triplet interligand π(terminal alkynyls) → π*(bridging alkynyl)/MMLCT [dσ*(Pt2) → π*(bridging alkynyl)] excited state. In terms of the fluxional behavior, calculations have been performed to study the details of the mechanisms for the three fluxional processes, which are the σ,π-alkynyl exchange, the ring-flipping, and the bridging-to-terminal alkynyl exchange processes. © 2010 American Chemical Society.en_HK
dc.languageengen_US
dc.publisherAmerican Chemical Society. The Journal's web site is located at http://pubs.acs.org/icen_HK
dc.relation.ispartofInorganic Chemistryen_HK
dc.titleComputational studies on the photophysical properties and NMR fluxionality of dinuclear platinum(II) a-frame alkynyl diphosphine complexesen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0020-1669&volume=49&issue=23&spage=10930&epage=10939&date=2010&atitle=Computational+studies+on+the+photophysical+properties+and+NMR+fluxionality+of+dinuclear+platinum(II)+a-frame+alkynyl+diphosphine+complexes-
dc.identifier.emailLam, WH:chsue@hku.hken_HK
dc.identifier.emailYam, VWW:wwyam@hku.hken_HK
dc.identifier.authorityLam, WH=rp00719en_HK
dc.identifier.authorityYam, VWW=rp00822en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1021/ic101271den_HK
dc.identifier.pmid21062025-
dc.identifier.scopuseid_2-s2.0-78650230132en_HK
dc.identifier.hkuros185279en_US
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-78650230132&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume49en_HK
dc.identifier.issue23en_HK
dc.identifier.spage10930en_HK
dc.identifier.epage10939en_HK
dc.identifier.eissn1520-510X-
dc.identifier.isiWOS:000284518800025-
dc.publisher.placeUnited Statesen_HK
dc.relation.projectInstitute of Molecular Functional Materials-
dc.identifier.scopusauthoridLam, WH=26642862800en_HK
dc.identifier.scopusauthoridYam, VWW=18539304700en_HK

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