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Heterodimetallic Ru–Fe complexes [(tppz)(PPh3)2RuL](ClO4) (L = C≡CFc, [1](ClO4); C≡C–C6H4–C≡CFc), [2](ClO4); C≡C–C6H4–C6H4–C≡CFc, [3](ClO4)) were synthesized by the reactions of [(tppz)(PPh3)2RuCl](ClO4) (tppz = 2,3,5,6-tetrakis(2-pyridyl)pyrazine) with ferrocence-acetylide ligands and characterized by ESI-MS, and 1H and 31P NMR spectroscopies. The structure of [1](PF6) was determined by X-ray crystallography. The electrochemical studies show that compounds [1](ClO4)–[3](ClO4) possess two widely separated anodic peaks, ascribable to one-electron oxidation of Fc and RuII, respectively. This assignment is further corroborated by the results of UV-vis-NIR, XPS, and theoretical calculation studies. Compound [1](ClO4) exhibits significant Ru…Fe metal–metal interactions across the Ru–C≡C–Fc backbone. As revealed by electrochemical, spectroscopic and theoretical computational studies, one-electron oxidized species [1a](ClO4)2 is between the electronically delocalized and valence-trapped state and shows a typical Robin–Day class II mixed-valence behavior. [ABSTRACT FROM AUTHOR]

A series of platinum(II) complexes bearing 1,3-bis(2-pyridylimino)isoindoline (BPI) derivatives as ligand have been prepared by substitution of the coordinated Cl in precursors [Pt(L)Cl] [L = L1 ( 1), L2 ( 2), L3 ( 3)] by a monodentate strong-field ligand such as CN-, CN-cyclohexyl, PPh3, NCS-, PhS-, or N(CN)2-. Most of these compounds display orange-to-red luminescence in both the solid state and solution at ambient temperature. Compared with precursors 1- 3, both low-energy absorption and emission bands in ligand-substituted platinum(II) complexes 4- 13 exhibit distinct blueshifts. The emission of platinum(II) complexes with CN-containing monodentate ligands shows progressive blueshifts with increasing ligand field strength: 609 ( 10, NCS-) → 603 [ 12, N(CN)2-] → 590 ( 4, CN-) → 581 nm ( 7, C≡N-cyclohexyl). The emission of complexes 4- 9 originates mainly from the 3[π → π*(BPI)] 3IL triplet excited state, mixed with some 3[dπ(Pt) → π*(BPI)] 3MLCT character. In contrast, the emission of 10- 13 arises from a clearly increased 3[π(L) → π*(BPI)] 3LLCT state with reduced 3[π → π*(BPI)] 3IL and 3[5d(Pt) → π*(BPI)] 3MLCT character. Noticeably, dicyanamido-linked dinuclear complex 13 displays a significant ligand-ligand electronic interaction between the two BPI across the Pt-N≡C-N-C≡N-Pt bridge with remarkable LLCT character from one BPI to the other. [ABSTRACT FROM AUTHOR]

A series of platinum(ii) complexes with 1,3-bis(2-pyridylimino)isoindoline (BPI) derivatives were prepared by substitution of the coordinated Cl in the precursor complex Pt(BPI)Cl with a N-heterocyclic ligand such as pyridine, phthalazine or phenanthridine. These complexes display orange to red luminescence in fluid dichloromethane solutions and in the solid states at room temperature. The photophysical properties were tuned by introducing electron-withdrawing -NO2or electron-donating -NH2to the BPI ligand. The DFT computational studies suggest that the emission in the N-heterocyclic ligand substituted platinum(ii) complexes originates mainly from the 3[π→π*(BPI)] 3IL triplet excited state, mixed with some 3[dπ(Pt)→π*(BPI)] 3MLCT character. Compared with the precursor Pt(BPI)Cl, both the low-energy absorption and the emission in the N-heterocyclic ligand substituted platinum(ii) complexes exhibits a distinct blue-shift due to an obviously enhanced contribution from the 3IL state and a reduced 3MLCT character. [ABSTRACT FROM AUTHOR]

A series of oxo-centred triruthenium-acetate complexes with valence iii,iii,iiwere prepared by reactions of [Ru3III,III,III]+precursor [Ru3O(OAc)6(py)2(CH3OH)]+(1) with 3-chloro-6-(pyrazol-1-yl)pyridazine (cppd), 3-chloro-6-(3,5-dimethylpyrazol-1-yl)pyridazine (cmppd), 3,6-bis(pyrazol-1-yl)pyridazine (ppd), 3,6-bis(3,5-dimethylpyrazol-1-yl)pyridazine (mppd) or 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine (bptz). When neutral Ru3III,III,IIprecursor Ru3O(OAc)6(CO)(CH3OH)2(2) was utilized, a stable low-valence Ru3III,II,IIderivative complex was successfully isolated. As established through crystal structural analyses, they were derived from 1or 2by substitution of the axial methanol and one of six bridging acetates in the parent Ru3(μ3-O)(μ-OAc)6cluster core as well as one axial pyridine in some cases. As revealed by electrochemical and spectroscopic studies, substituting one of the six bridging acetates in the parent Ru3(μ3-O)(μ-OAc)6cluster core significantly modifies the electronic and redox characteristics. Compared with those for the parent compound [Ru3O(OAc)6(py)3]+, triruthenium-based redox potentials of these derivatives show remarkable positive shifts. [ABSTRACT FROM AUTHOR]

Abstract: The preparation, characterization and photophysical properties of heterobinuclear complexes {Pt(C^N^N)(Chfac)3 (C^N^N=2-(6-(naphthalen-3-yl)-4-phenylpyridin-2-yl)pyridine; HCsp sp="0.25" />=5-ethynyl-2,2′-bipyridine; Ln=Nd, Eu, Yb; hfac=hexafluoroacetylacetonate) are described. With excitation at 390⩽ λ ex ⩽500nm which is the MLCT/LLCT absorption region of the Pt(C^N^N)(Comophore, lanthanide luminescence is successfully attained by Pt→Ln energy transfer from the platinum(II) antenna chromophore to the lanthanide center across the bridging Cnd. [Copyright &y& Elsevier]

Abstract: A series of cyclometallated iridium(III) acetylide complexes Ir(ppy)2(PPh3)(C:hsp sp="0.12" />=C6H5 3, C6H4But-4 4, C6F5 5, C6H4COMe-4 6, SiMe3 7) were synthesized by substitution of coordination chloride in precursor Ir(ppy)2(PPh3)Cl (2, ppy=2-phenylpyridine) with an acetylide ligand. These complexes are brightly luminescent in fluid dichloromethane at ambient temperature, originating from 3MLCT/3LLCT/3IL states as supported by TD-DFT studies. It is demonstrated that substitution of coordination chloride in precursor 2 (λ em =456 and 485nm, Φ em =1.6%) with an acetylide ligand results in obvious red-shift of the emission as well as significant enhancement of the luminescence efficiency in 3–7 (λ em =480–510nm, Φ em =9.5%–19%) since the energy level of non-emissive d–d transition is highly raised and thus d–d state deactivation is significantly suppressed. [Copyright &y& Elsevier]