Luminescence, electrochemistry and host–guest properties of dinuclear platinum(ii) terpyridyl complexes of sulfur-containing bridging ligands

Tang, Rowena Pui-Ling; Wong, Keith Man‐Chung; Zhu, Nianyong; Yam, Vivian Wing‐Wah

doi:10.1039/b821264c

Cited by 26 publications

(15 citation statements)

References 65 publications

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“…A slight variation in Pt–S bond distances was noticed in all the three structures: 2.37−2.39 Å for for 4a-I , 2.36–2.37 Å for 4b-II , and 2.37–2.39 Å for 4c-III . These distances match well with the Pt–S bond distances in analogous complex [Pt 2 (μ- o -SC 6 H 4 (CF 3 )) 2 (dppe) 2 ](OTf) 2 (2.38 Å) but are longer than those in in [Pt 2 (dppf) 2 (C 8 H 8 NS)](BF 4 ) (2.34 Å) and [Pt 2 (terpyridine) 2 (1,3-SC 6 H 4 S)] 2 (PF 6 ) 2 (2.31 Å) . The bite angles (101–102°) for 4a-I and 4b-II agree well with those of complexes [Pt(Xantphos)Cl 2 ] (101°) and [Pt 3 (Xantphos) 2 {(SeCH 2 ) 2 C(CH 2 OH) 2 }]Cl 2 ] (101°) but are smaller than that of the allyl complex [Pt(η 3 -allyl)(Xantphos)](OTf) (107°), whereas the bite angles 98–99° for 3c-III are shorter than the usual values for a wide bite angle (>101°) in Xantphos complexes.…”

Section: Resultssupporting

confidence: 78%

“…However, the calculations showed that the similar complex [M′ 2 (Xantphos) 2 (1,3-SC 6 H 4 S)] 2 (OTf) 4 ( II′ ) with phenylene-1,3-dithiolate and the possibility of another neutral complex [M′ 2 (Xantphos) 2 (SC 6 H 4 S) 2 ] ( IV ) are inherently unstable, probably due to the overcrowding of ligands (Scheme S1). The reported platinum complex [Pt 2 (terpyridine) 2 (1,3-SC 6 H 4 S)](PF 6 ) 2 exist as linear dimeric complex …”

Section: Resultsmentioning

confidence: 99%

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Xantphos-Capped Pd(II) and Pt(II) Macrocycles of Aryldithiolates: Structural Variation and Catalysis in C–C Coupling Reaction

et al. 2019

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The self-assembly of Xantphos-capped M(OTf)2 (M = cis-[M′(Xantphos)]2+; M′ = Pd, Pt) with bridging ligands 1,4-benezenedithiol or 4,4′-biphenyldithiol has been investigated. The reactions have yielded complexes [M{S(C6H4) n SH}]2(OTf)2 (I) and [M 2{S(C6H4) n S}]2(OTf)4 (II) (n = 1 or 2). The equilibrium between I and II has been established in platinum complexes for n = 2, whereas the analogous Pd complex exclusively exist as II. These results are different from our previously reported dppe or triethyl phosphine-capped complexes which showed only type II. The same reaction with 1,3-benezenedithiol lead to the complex [M 2(SC6H4SSC6H4S)](OTf)2 (III), containing a S–S bond between two thiolate ligands, formed via a complex of type I in solution. Characterization of the complexes was accomplished by NMR spectroscopy, UV–vis spectroscopy and mass spectrometry, and X-ray crystallography. Density functional calculations were performed to estimate the relative stability of three types of complexes. The palladium complexes are excellent catalysts in Suzuki C–C cross coupling reactions under mild conditions, and can be reused eight times without losing significant yield. The activity of the Pd catalysts derived from three dithiol ligand follows opposite trend of the stability as III > II > I. The comparative catalytic activity of the tetranuclear Pd complexes (II) of bis-phosphines of varied bite angles, including the structurally characterized [Pd2(dppf)2(SC12H8S)]2(OTf)4 has also been demonstrated.

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Section: Resultssupporting

confidence: 78%

Section: Resultsmentioning

confidence: 99%

Xantphos-Capped Pd(II) and Pt(II) Macrocycles of Aryldithiolates: Structural Variation and Catalysis in C–C Coupling Reaction

et al. 2019

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“…For example the two ppy ligands of 3a give two different sets of signals with the chemical shifts of the protons of the overlapping ppy being 0.4–0.9 ppm lower than that of the nonoverlapping one. Most of the protons of the terpy do not overlap with L, but the H 13 , which is covered significantly by L, shows an upfield-shifted signal, that is, the H 13 signals of 3a (δ 8.34) and 4a (δ 8.39) are lower than that of the corresponding proton in similar complexes such as [Pt 2 (terpy) 2 (μ-SMe)](ClO 4 ) 3 (δ 9.7), and [Pt(terpy)(SCH 2 CH 2 OH)](PF 6 ) (δ 9.16) . The results indicate that the rings remain overlapped in the solutions and probably have the same conformations as depicted in the X-ray crystal structures.…”

Section: Resultsmentioning

confidence: 99%

Coupling d⁶ Ir(III) and d⁸ Pt(II) Chromophores

2018

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Two classes of widely studied luminescent metal complexes are octahedral d (i.e., Ir) and square planar d (i.e., Pt) polypyridyl complexes, which have distinctly different photophysics and photoreactivity. In this study we report a series of d-d Ir-Pt hybrid complexes arising from coordination of metalloligands IrL(benzene-1-thioether-2-thiolate) or Ir(L)(benzene-1,2-dithiolate) anion [L = 2-phenylpyridine (ppy), 2-(2,4-difluorophenyl)pyridine (dfppy), or 1-phenylisoquinoline (piq)] to Pt(terpy) (terpy = 2,2':6',2″-terpyridine). X-ray crystal structures of the Ir-Pt complexes show the IrL and Pt(terpy) chromophores are cofacially oriented with interplanar distances of 3.268-3.442 Å. Density functional theory (DFT) calculations show that the highest occupied molecular orbital and the lowest unoccupied molecular orbital are localized in the IrL and the Pt(terpy), respectively. All the complexes display a low-energy absorption band (λ = 460-534 nm, ε = (0.75-2.13) × 10 M cm), which is attributed to interchromophore-charge-transfer (ICCT) transition, according to time-dependent DFT calculations. The ICCT excited state is emissive, giving long-lived phosphorescence that reaches as low as near-infrared (λ = 668-710 nm, τ = 0.17-0.79 μs).

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“…Bimetallic complexes exhibit unique structural and optical properties that differ from mononuclear metal center complexes, as facilitated by the presence of the metal–metal bond. − With small bond lengths, metal-to-ligand charge transfer (MLCT) is induced, but with longer bonds metal–metal-to-ligand charge transfer (MMLCT) occurs. Platinum–platinum dimers showcase such phenomena across a broad range of complex structures …”

Section: Introductionmentioning

confidence: 99%

Orbital Control and Coherent Charge Transport in Transition Metal Platinum(II)–Platinum(II) Lantern Complexes in Molecular Junctions

Jones¹,

Mosquera²,

Ratner

et al. 2020

J. Phys. Chem. C

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Platinum(II) dimers in organometallic complexes exhibit oscillatory vibrational charge transfer with optical excitation and whose nature depends strongly on the Pt–Pt distance. Yet, the electronic transport of such devices has not been studied. We take a well-reported Pt(II) dimer complex that is ideal for transport in a molecular junction and subject it to a battery of electronic structure–property calculations. With DFT, we find the orbital nature of the HOMO level to not be solely induced by the 5d z 2 orbital as long thought, but rather a complex mixture with significant contributions from 6s orbital states from the Au electrodes that have not been considered before. We probe how the chemical tuning of the ligand affects the Pt–Pt bond length and thus conduction, by systematically modifying both the bridging ligands (BL) and cyclometallating ligands (CMLs) with donor (methyl) and acceptor (fluorine) derivatives. With nonequilibrium Green’s functions (NEGF-DFT), we find patterns between the conductivity, substituent and ligand type. Methyl groups tend to increase the conduction and fluorine does vice versa, but it is strongly dependent on the ligand. We modify the atoms on the bridging ligand in contact with the Pt centers and derivatize with N, O, S and Se. The heavy elements such as S and Se give a decreasing conductance due to the interaction of the bonding π orbitals with the antibonding HOMO level. This is evident from the bond orders being ∼1 with no ligands but ≪1 with ligands, as revealed with Mayer, Gophinatan–Jug (G-J) and Nalewajski–Mrozek (N-M) indices. The same heavy elements also bind strongly to Pt, making the ligands a more viable pathway for the conduction and giving rise to destructive quantum interference at the second Pt site. The projected density of states (DOS) show the bonding states to be in the occupied eigenchannel, and the Seebeck thermopower function confirms the majority charge carrier to be p-type. The donor/acceptor correlation with the ligand type and degree of substitution shows enhanced chemical tuning is possible for transition-metal complex (TMC) junctions.

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Luminescence, electrochemistry and host–guest properties of dinuclear platinum(ii) terpyridyl complexes of sulfur-containing bridging ligands

Cited by 26 publications

References 65 publications

Xantphos-Capped Pd(II) and Pt(II) Macrocycles of Aryldithiolates: Structural Variation and Catalysis in C–C Coupling Reaction

Xantphos-Capped Pd(II) and Pt(II) Macrocycles of Aryldithiolates: Structural Variation and Catalysis in C–C Coupling Reaction

Coupling d⁶ Ir(III) and d⁸ Pt(II) Chromophores

Orbital Control and Coherent Charge Transport in Transition Metal Platinum(II)–Platinum(II) Lantern Complexes in Molecular Junctions

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Luminescence, electrochemistry and host–guest properties of dinuclear platinum(ii) terpyridyl complexes of sulfur-containing bridging ligands

Cited by 26 publications

References 65 publications

Xantphos-Capped Pd(II) and Pt(II) Macrocycles of Aryldithiolates: Structural Variation and Catalysis in C–C Coupling Reaction

Xantphos-Capped Pd(II) and Pt(II) Macrocycles of Aryldithiolates: Structural Variation and Catalysis in C–C Coupling Reaction

Coupling d6 Ir(III) and d8 Pt(II) Chromophores

Orbital Control and Coherent Charge Transport in Transition Metal Platinum(II)–Platinum(II) Lantern Complexes in Molecular Junctions

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Coupling d⁶ Ir(III) and d⁸ Pt(II) Chromophores