Bimetallic Pt(II)-bipyridyl-diacetylide/Ln(III) tris-diketonate adducts based on a combination of coordinate bonding and hydrogen bonding between the metal fragments: Syntheses,structures and photophysical properties

The luminescent Pt(II) complex [Pt(4,4′-^tBu₂-bipy){CC-(5-pyrimidinyl)}₂] (1) was prepared by coupling of [Pt(4,4′-^tBu₂-bipy)Cl₂] with 5-ethynyl-pyrimidine, and contains two pyrimidinyl units pendant from a Pt(II) bipyridyl diacetylide core; it shows luminescence at 520 nm which is typical of Pt(II) luminophores of this type. Reaction with [Ln(hfac)₃(H₂O)₂] (hfac = anion of hexafluoroacetylacetone) affords as crystalline solids the compounds [1 · {Ln(hfac)₃(H₂O)}{Ln(hfac)₃(H₂O)₂}] (Ln = Nd, Gd, Er, Yb), in which the {Ln(hfac)₃(H₂O)} unit is coordinated to one pyrimidine ring via an N atom, whereas the {Ln(hfac)₃(H₂O)₂} unit is associated with two N atoms, one from each pyrimidine ring of 1, via N?HOH hydrogen-bonding interactions involving the coordinated water ligands on the lanthanide centre. Solution spectroscopic studies show that the luminescence of 1 is partly quenched on addition of [Ln(hfac)₃(H₂O)₂] (Ln = Er, Nd) by formation of Pt(II)/Ln(III) adducts in which Pt(II)→Ln(III) photoinduced energy-transfer occurs to the low-lying f–f levels of the Ln(III) centre. Significant quenching occurs with both Er(III) and Nd(III) because both have several f–f states which match well the ³MLCT emission energy of 1. Time-resolved luminescence studies show that Pt(II)→Er(III) energy-transfer (7.0 × 10⁷ M⁻¹) is around three times faster than Pt(II)→Nd(III) energy-transfer (≈2 × 10⁷ M⁻¹) over the same distance because the luminescence spectrum of 1 overlaps better with the absorption spectrum of Er(III) than with Nd(III). In contrast Yb(III) causes no significant quenching of 1 because it has only a single f–f excited level which is a poor energy match for the Pt(II)-based excited state.     

Hydrothermal synthesis and luminescence behavior of rare-earth-doped NaLa(WO4)2 powders

NaLa(WO₄)₂ powders doped with Eu³⁺, Nd³⁺, and Er³⁺ have been synthesized by a mild hydrothermal method and a crystal of exclusive scheelite phase could be obtained at low temperature. From the spectrum of Eu³⁺ it has been concluded that the dopant Eu³⁺ ion occupies a La³⁺ site and mainly takes the site with C₂ symmetry. The higher quenching concentration can be observed in the Eu³⁺-doped NaLa(WO₄)₂ powders. The Er³⁺- and Nd³⁺-doped NaLa(WO₄)₂ powders exhibit luminescence in the near infrared (Er³⁺ at 1550 nm, and Nd³⁺ at 1060 nm). The transition mechanism of the up-conversion luminescence of the Er³⁺-doped NaLa(WO₄)₂ powders can be ascribed to two photons absorption process.     

Synthesis,crystal structures and NIR luminescence of sandwich-like tetradentate salophen phenoxo-bridged heterotrinuclear metal complexes

Six phenoxo-bridged tetradentate salophen heterotrinuclear Zn₂Ln complexes, [Ln(ZnL)₂(NO₃)₃(CH₃OH)₂]·CH₃OH·CH₂Cl₂ [Ln?=?Pr (1), Nd (2)] and [Ln(ZnL)₂(NO₃)₃(CH₃OH)]·CH₃OH·CH₂Cl₂ [Ln?=?Eu (3), Ho (4), Er (5), and Yb (6)], have been isolated from reactions of N,N′-bis(salicylidene)-1,2-(phenylene-diamine) with Ln(NO₃)₃6H₂O and Zn(OAc)₂2H₂O. X-ray diffraction analysis reveals that 1–6 are isomorphic with phenoxo-bridged, sandwich-like {Zn₂Ln} core. Near infrared (NIR) luminescence spectra show that 6 exhibits typical emission of Yb³⁺ upon excitation at the ligand-centered absorption band at 357?nm.     

Thermo-induced structural transformation with synergistic optical and magnetic changes in ytterbium and erbium complexes

Dinuclear ytterbium and erbium based bifunction complexes Ln₂L₂(depma₂)Cl₂ (1-Ln, Ln = Yb and Er, H₂L = N¹,N³-bis(salicylideneimino)diethylenetriamine, depma₂ = dimerized 9-diethyl-phosphonomethylanthracene) are reported. They undergo thermo-induced consecutive phase transitions, first the dissociation of depma₂ ligand forming LnL(depma)Cl (2-Ln) and then the release of chloroethane forming LnL(epma) (3-Ln, epma = 9-ethylphosphonomethylanthrancene). The structural transformations are accompanied with synergetic switch of the luminescence in visible and NIR regions and also magnetic dynamics.     

2,2′‐Bipyrimidine as Efficient Sensitizer of the Solid‐State Luminescence of Lanthanide and Uranyl Ions from Visible to Near‐Infrared

Treatment of Ln(NO₃)₃?nH₂O with 1 or 2 equiv 2,2′‐bipyrimidine (BPM) in dry THF readily afforded the monometallic complexes [Ln(NO₃)₃(bpm)₂] (Ln=Eu, Gd, Dy, Tm) or [Ln(NO₃)₃(bpm)₂]?THF (Ln=Eu, Tb, Er, Yb) after recrystallization from MeOH or THF, respectively. Reactions with nitrate salts of the larger lanthanide ions (Ln=Ce, Nd, Sm) yielded one of two distinct monometallic complexes, depending on the recrystallization solvent: [Ln(NO₃)₃(bpm)₂]?THF (Ln=Nd, Sm) from THF, or [Ln(NO₃)₃(bpm)(MeOH)₂]?MeOH (Ln=Ce, Nd, Sm) from MeOH. Treatment of UO₂(NO₃)₂?6H₂O with 1 equiv BPM in THF afforded the monoadduct [UO₂(NO₃)₂(bpm)] after recrystallization from MeOH. The complexes were characterized by their crystal structure. Solid‐state luminescence measurements on these monometallic complexes showed that BPM is an efficient sensitizer of the luminescence of both the lanthanide and the uranyl ions emitting visible light, as well as of the Yb^III ion emitting in the near‐IR. For Tb, Dy, Eu, and Yb complexes, energy transfer was quite efficient, resulting in quantum yields of 80.0, 5.1, 70.0, and 0.8 %, respectively. All these complexes in the solid state were stable in air.     

Synthesis,Structures, and Luminescent Properties of Chloride and Nitrate LnIII Complexes Coordinated by tris(Pyrazolyl)methane

We report the synthesis of Ln³⁺ nitrate [Ln(Tpm)(NO₃)₃] ⋅ MeCN (Ln=Yb ( 1Yb ), Eu ( 1Eu )) and chloride [Yb(Tpm)Cl₃] ⋅ 2MeCN ( 2Yb ), [Eu(Tpm)Cl₂(μ-Cl)]₂ ( 2Eu ) complexes coordinated by neutral tripodal tris(3,5-dimethylpyrazolyl)methane (Tpm). The crystal structures of 1Ln and 2Ln were established by single crystal X-ray diffraction, while for 1Yb high resolution experiment was performed. Nitrate complexes 1Ln are isomorphous and both adopt mononuclear structure. Chloride 2Yb is monomeric, while Eu³⁺ analogue 2Eu adopts a binuclear structure due to two μ²-bridging chloride ligands. The typical lanthanide luminescence was observed for europium complexes ( 1Eu and 2Eu ) as well as for terbium and dysprosium analogues ([Ln(Tpm)(NO₃)₃] ⋅ MeCN, Ln=Tb ( 1Tb ), Dy ( 1Dy ); [Ln(Tpm)Cl₃] ⋅ 2MeCN, Ln=Tb ( 2Tb ), Dy ( 2Dy )).     

Hydrothermal syntheses and characterization of four 2-D lanthanide coordination polymers with glutarate and 1,10-phenanthroline

Four 2-D coordination polymers Ln₂(phen)₂(C₅H₆O₄)₃ [Ln?=?Pr(1), Eu(2), Er(3), Yb(4), phen?=?1,10-phenanthroline] were obtained via hydrothermal reactions and determined by X-ray diffraction analysis. The crystal structure data reveal that these complexes are isostructural. In the asymmetric unit, the two Ln(III) ions are nine-coordinate and have similar coordination environments. The Ln(III) ions are built into 2-D layers by three different coordination modes of glutarate. The resulting 2-D layer forms 3-D supramolecular architecture by two types of π···π stacking interactions. All the complexes were characterized by IR spectra and thermogravimetric analysis, and the emission spectrum shows that Eu₂(phen)₂(C₅H₆O₄)₃ possesses strong luminescence.     

Synthesis and photophysical properties of Ir<Superscript>III</Superscript>-Ln<Superscript>III</Superscript> (Ln = Nd,Yb, Er) bimetallic complexes containing bipyrimidines as bridging ligands

Bipyrimidines have been chosen as (N∧N)(N∧N) bridging ligands for connecting metal centers. Ir^III-Ln^III (Ln = Nd, Yb, Er) bimetallic complexes [Ir(dfppy)₂(μ-bpm)Ln(TTA)₃]Cl were synthesized by using Ir(dfppy)₂(bpm)Cl as the ligand coordinating to lanthanide complexes Ln(TTA)₃·2H₂O. The stability constants between Ir(dfppy)₂(bpm)Cl and lanthanide ions were measured by fluorescence titration. The obvious quenching of visible emission from Ir^III complex in the Ir^III-Ln^III (Ln = Nd, Yb, Er) bimetallic complexes indicates that energy transfer occurred from Ir^III center to lanthanides. NIR emissions from Nd^III, Yb^III, and Er^III were obtained under the excitation of visible light by selective excitation of the Ir^III-based chromophore. It was proven that Ir(dfppy)₂(bpm)Cl as the ligand could effectively sensitize NIR emission from Nd^III, Yb^III, and Er^III.     

Tune color of single-phase LiGd(MoO4)2-X(WO4)X: Sm3+, Tb3+ via adjusting the proportion of matrix and energy transfer to create white-light phosphor

A series of LiGd(MO₄)₂: Sm³⁺, Tb³⁺ (M = Mo, W) phosphors was prepared by a conventional solid state reaction method. Powder X-Ray diffraction (XRD) analysis reveals that the compounds are of the same structure type. Their luminescent properties have been studied. The optimal doping concentrations are 8% for Sm³⁺ and 18% for Tb³⁺ in the LiGd(MoO₄)₂ host. Sm³⁺ and Tb³⁺ have different sensitivity to the Mo/W ratio. For LiGd(MoO₄)_2-X(WO₄)_X: Sm³⁺ (X = 0, 0.4, 0.8, 1.2, 1.6, 2.0), the strongest emission intensity is 1.766 times than that of the weakest, while 171 times for LiGd(MoO₄)_2-X(WO₄)_X: Tb³⁺. The experimental results show that Mo/W ratio strong influences on the properties of LiGd(MoO₄)_2-X(WO₄)_X: Tb³⁺. With the increasing of WO₄²⁻ groups concentration, the shape of characteristic excitation peaks of Tb³⁺ is almost the same and the excitation intensity gradually increase. Moreover, the energy transfer from Tb³⁺ to Sm³⁺ has been realized in the co-doped phosphors. The experimental analysis and theoretical calculations reveal that the quadrupole–quadrupole interaction is the dominant mechanism for the Tb³⁺→Sm³⁺ energy transfer. Therefore, luminous intensity can be adjusted by different sensitivities to matrix composition and energy transfer from Tb³⁺→Sm³⁺. By this tuning color method, white-light-emitting phosphor has been prepared. The excitation wavelength is 378 nm, and this indicates that the white-light-emitting phosphor could be pumped by near-UV light.     

Triphenylphosphane Oxide Complexes of Lanthanide Nitrates: Polymorphs and Photophysics

A series of mer‐[Ln(NO₃)₃(Ph₃PO)₃] complexes were prepared from Ln(NO₃)₃ · xH₂O and Ph₃PO in chloroform (Ln = La, Nd, Sm, Eu, Gd, Tb, Dy, and Er). The La and Nd complexes were 0.25 CHCl₃ solvates, whereas the others were solvent‐free. The identical reaction using Yb(NO₃)₃ · xH₂O produced the unique salt trans‐[Yb(NO₃)₂(Ph₃PO)₄][Yb(NO₃)₄(Ph₃PO)] · Et₂O. All nitrate ions in all complexes are η²‐chelating. A comparison of the various [Ln(NO₃)₃(Ph₃PO)₃] structures, including those in the literature, reveals at least four common polymorphs, each of which is represented by isomorphic structures of multiple Ln ions. Luminescence of mer‐[Ln(NO₃)₃(Ph₃PO)₃] (Ln = Y, La, Nd, Sm, Eu, Gd, Tb, and Dy), trans‐[Yb(NO₃)₂(Ph₃PO)₄][Yb(NO₃)₄(Ph₃PO)] and Ph₃PO assignments are reported. Latva's empirical rule allows for the antenna effect, in which energy is transferred from the triplet state of the Ph₃PO ligand, to occur only for Tb³⁺. Excitation via Ph₃PO results in strong green luminescence for Tb³⁺ having twice the intensity as that which results from direct excitation of the f‐f transitions.     

Investigation of Er3+, Yb3+, Nd3+ doped yttrium calcium oxyborate for photon upconversion applications

In this work, investigation have been done on polycrystalline yttrium calcium oxyborate (YCa₄O(BO₃)₃) for the realization of existence of second harmonic generation and other photon upconversion processes as concurrent effect with the aid of Er, Yb, Nd trivalent lanthanide ions. Pure, Er:Yb co-doped and Er:Yb:Nd triply-doped YCa₄O(BO₃)₃ samples were prepared through solid state reaction and the phase identification has been done using powder X-ray diffraction spectral analysis. FTIR spectra show that the dopants increases the absorption of functional groups and modifies the lattice vibrational modes of YCa₄O(BO₃)₃. The spectral overlap of optical absorption bands of Er³⁺, Yb³⁺, Nd³⁺ ions in 840 nm–1070 nm region indicates the prospect of energy transfer between these ions. The photoluminescence spectrum of Er:Yb:Nd triply doped sample show good enhancement compared to pure and Er:Yb co-doped YCa₄O(BO₃)₃ samples. In the photon upconversion test carried out using 1064 nm Nd:YAG laser YCa₄O(BO₃)₃:Er:Yb:Nd sample produced green light with efficiency higher than the other two samples. Surface morphology of the samples was recorded using field emission scanning electron microscope and analysed. The elemental composition of the samples has been confirmed by energy dispersive X-ray spectral analysis.     

Enhancing Dye-Triplet-Sensitized Upconversion Emission Through the Heavy-Atom Effect in CsLu2F7:Yb/Er Nanoprobes

Lanthanide (Ln³⁺)-doped upconversion (UC) nanoprobes, which have drawn extensive attention for various bioapplications, usually suffer from small absorption cross-sections and weak luminescence intensity of Ln³⁺ ions. Herein, we report the controlled synthesis of a new class of Ln³⁺-doped UC nanoprobes based on CsLu₂F₇:Yb/Er nanocrystals (NCs), which can effectively increase the intersystem crossing (ISC) efficiency from singlet excited state to triplet excited state of IR808 up to 99.3 % through the heavy atom effect. By virtue of the efficient triplet sensitization of IR808, the optimal UC luminescence (UCL) intensity of IR808-modified CsLu₂F₇:Yb/Er NCs is enhanced by 1309 times upon excitation at 808 nm. Benefiting from the intense dye-triplet-sensitized UCL, the nanoprobes are demonstrated for sensitive assay of extracellular and intracellular hypochlorite with an 808-nm/980-nm dual excited ratiometric strategy.     

Cerium luminescence in nd perovskites

The luminescence of Ce³⁺ in perovskite (ABO₃) hosts with nd⁰ B-site cations, specifically Ca(Hf,Zr)O₃ and (La,Gd)ScO₃, is investigated in this report. The energy position of the Ce³⁺ excitation and emission bands in these perovskites is compared to those of typical Al³⁺ perovskites; we find a Ce³⁺ 5d¹ centroid shift and Stokes shift that are larger versus the corresponding values for the Al³⁺ perovskites. It is also shown that Ce³⁺ luminescence quenching is due to Ce³⁺ photoionization. The comparison between these perovskites shows reasonable correlations between Ce³⁺ luminescence quenching, the energy position of the Ce³⁺ 5d¹ excited state with respect to the host conduction band, and the host composition.     

Cation‐Directed Dimeric versus Tetrameric Assemblies of Lanthanide‐Stabilized Dilacunary Keggin Tungstogermanates

Reaction of mid‐ to late lanthanide ions with GeO₂ and Na₂WO₄ in NaOAc buffer results in a library of [Ln₂(GeW₁₀O₃₈)]^6? clusters ( Ln₂ ), which consist of dilacunary Keggin fragments stabilized by the insertion of 4f atoms in the vacant sites and show the ability to undergo cation‐directed self‐assembly processes. In the presence of Na⁺, two β‐ Ln₂ subunits assemble by means of Ln‐O(WO₅)‐Ln bridges to form the chiral [Ln₄(H₂O)₆(β‐GeW₁₀O₃₈)₂]^12? dimeric anions (ββ‐ Ln₄ , Ln=Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu). When Cs⁺ is present, two Ln₄ ‐like dimers further assemble into the [{Ln₄(H₂O)₅(GeW₁₀O₃₈)₂}₂]^24? species ( Ln₈ , Ln=Ho, Er, Tm, Yb, Lu). Two types of tetramers coexist in the solid state: One shows a full ββ‐ Ln₈ architecture, whereas the other one is a mixed αβ‐ Ln₈ assembly in which each β‐subunit is linked to its corresponding α‐ Ln₂ derivative. Regardless of differences in isomeric forms and the relative arrangement of Ln₂ subunits, all anions display virtually identical {Ln₄} cores as a common structural feature. A combination of ESI mass spectrometry and ¹⁸³W NMR spectroscopy experiments indicates that Ln₈ tetramers fragment into Ln₄ dimers upon dissolution, which undergo partial dissociation into Ln₂ monomers and slow dimer/monomer equilibration. This is most likely followed by β‐to‐α isomerization of Ln₂ clusters with consequent reassembly, as indicated by isolation of three additional αα‐ Ln₄ derivatives. Magnetic and photoluminescence properties in the Na ‐ββ‐ Ln₄ series are also discussed.     

Cooperative Sensitization Upconversion in Solution Dispersions of Co-Crystal Assemblies of Mononuclear Yb3+ and Eu3+ Complexes

Lanthanide upconversion luminescence in nanoparticles has prompted continuous breakthroughs in information storage, temperature sensing, and biomedical applications, among others. Achieving upconversion luminescence at the molecular scale is still a critical challenge in modern chemistry. In this work, we explored the upconversion luminescence of solution dispersions of co-crystals composed of discrete mononuclear Yb(DBM)₃Bpy and Eu(DBM)₃Bpy complexes (DBM: dibenzoylmethane, Bpy: 2,2′-bipyridine). The 613 nm emission of Eu³⁺ was observed under excitation of Yb³⁺ at 980 nm. From the series of molecular assemblies studied, the most intense luminescence was obtained for a 1 : 1 molar ratio of Yb³⁺ : Eu³⁺, resulting in a high quantum yield of 0.67 % at 2.1 W cm⁻². The structure and energy transfer mechanism of the assemblies were fully characterized. This is the first example of an Eu³⁺-based upconverting system composed of two discrete mononuclear lanthanide complexes present as co-crystals in non-deuterated solution.     

Lanthanide perchlorate complexes of 4-cyano pyridine-N-oxide, 4-chloro 2-picoline-N-oxide and 4-dimethyl amino-2-picoline-N-oxide

Complexes of lanthanide perchlorates with 4-cyano pyridine-1-oxide, 4-chloro 2-picoline-1-oxide and 4-dimethyl-amino 2-picoline-1-oxide have been isolated for the first time and characterized by analysis, conductance, infrared, NMR and electronic spectra. The complexes of 4-cyano pyridine-1-oxides have the composition Ln(CyPO)₆(ClO₄)₃. 2H₂O (Ln=La, Sm, Dy and Ho); Ln(CyPO)₇ (ClO₄)₃. 2H₂O (Ln=Pr, Nd, Er and Yb); and Ln(CyPO)₅ (ClO₄)₃. 2H₂O (Ln=Gd and Tb). The complexes of 4-chloro 2-picoline-1-oxide analyse for the formulae Ln(CpicO)₆ (ClO₄)₃ (Ln=La, Pr, Nd and Ho); and Ln (CpicO)₅ (ClO₄)₃ (Ln=Er and Yb), and those of 4-dimethylamino 2-picoline-1-oxide for Ln(DMPicO)₆ (ClO₄)₃ (Ln=La and Nd); Ln(DMPicO)₇ (ClO₄)₃ (Ln=Gd, Er and Yb); and Ln(DMPicO)₈ (ClO₄)₃ (Ln=Dy and Ho).     

Reactions of CpCuPPh3 with Lanthanides and Their Compounds

CpCuPPh₃ reacts with Pr, Er, Yb, Cp₂Yb, and SmI₂(THF)₄ to form, in high yields, lanthanide cyclopentadienyl derivatives Cp₂Yb, Cp₃Ln (Ln = Pr, Er, Yb), and CpSmI₂(THF)₂. The initial agent CpCuPPh₃ can be prepared in 95-98% yield by the reaction of t-BuOCu with CpH in the presence of PPh₃.     

Unprecedented Sensitization of Visible and Near‐Infrared Lanthanide Luminescence by Using a Tetrathiafulvalene‐Based Chromophore

Ligand L was synthesized and then coordinated to [Ln(hfac)₃] ? 2 H₂O (Ln^III=Tb, Dy, Er; hfac^?=1,1,1,5,5,5‐hexafluoroacetylacetonate anion) and [Ln(tta)₃]?2 H₂O (Ln^III=Eu, Gd, Tb, Dy, Er, Yb; tta^?=2‐thenoyltrifluoroacetonate) to give two families of dinuclear complexes [Ln₂(hfac)₆( L )] ? C₆H₁₄ and [Ln₂(tta)₆( L )] ? 2 CH₂Cl₂. Irradiation of the ligand at 37 040 cm^?1 and 29 410 cm^?1 leads to tetrathiafulvalene‐centered and 2,6‐di(pyrazol‐1‐yl)‐4‐pyridine‐centered fluorescence, respectively. The ligand acts as an organic chromophore for the sensitization of the infrared Er^III (6535 cm^?1) and Yb^III (10 200 cm^?1) luminescence. The energies of the singlet and triplet states of L are high enough to guarantee an efficient sensitization of the visible Eu^III luminescence (17 300–14 100 cm^?1). The Eu^III luminescence decay can be nicely fitted by a monoexponential function that allows a lifetime estimation of (0.49±0.01) ms. Finally, the magnetic and luminescence properties of [Yb₂(hfac)₆( L )] ? C₆H₁₄ were correlated, which allowed the determination of the crystal field splitting of the ²F_7/2 multiplet state with M_J=±1/2 as ground states.     

Visible and near-infrared luminescence of polycatenated cationic pyridinone lanthanide networks

A series of isomorphic lanthanide coordination polymers [Ln(III)(MBP)_2(NO_3)_2(Br)?2C_3H_6O] [Ln=Eu, Tb, Er, Yb, and Gd; MBP=N,N′-methylene-bis(pyridin-4-one)] featuring polycatenated sql cationic network and incorporated bromide counter ion were prepared. Their visible and near-infrared(NIR) luminescence properties were characterized by steady-state excitation and emission spectra, as well as luminescence lifetimes and quantum yields. The D_(2d) dodecahedron coordination geometry causes visible light excitations and strongly monochromatic emissions. The external heavy-atom environment induces remarkable enhancement on the NIR emissions. The sensitization processes are revealed by analyzing the electronic properties of MBP ligand.     

Structural and photophysical properties of coordination networks combining [Ru(bipy)(CN)4]2- anions and lanthanide(III) cations: rates of photoinduced Ru-to-lanthanide energy transfer and sensitized near-infrared luminescence

Co-crystallization of K2[Ru(bipy)(CN)4] with lanthanide(III) salts (Ln = Pr, Nd, Gd, Er, Yb) from aqueous solution affords coordination oligomers and networks in which the [Ru(bipy)(CN)4]2- unit is connected to the lanthanide cation via Ru-CN-Ln bridges. The complexes fall into two structural types: [{Ru(bipy)(CN)4}2{Ln(H2O)m}{K(H2O)n}] x xH2O (Ln = Pr, Er, Yb; m = 7, 6, 6, respectively), in which two [Ru(bipy)(CN)4]2- units are connected to a single lanthanide ion by single cyanide bridges to give discrete trinuclear fragments, and [{Ru(bipy)(CN)4}3{Ln(H2O)4}2] x xH2O (Ln = Nd, Gd), which contain two-dimensional sheets of interconnected, cyanide-bridged Ru2Ln2 squares. In the Ru-Gd system, the [Ru(bipy)(CN)4]2- unit shows the characteristic intense (3)metal-to-ligand charge transfer luminescence at 580 nm with tau = 550 ns; with the other lanthanides, the intensity and lifetime of this luminescence are diminished because of a Ru --> Ln photoinduced energy transfer to low-lying emissive states of the lanthanide ions, resulting in sensitized near-infrared luminescence in every case. From the degree of quenching of the Ru-based emission, Ru --> Ln energy-transfer rates can be estimated, which are in the order Yb (k(EnT) approximately 3 x 10(6) sec(-1), the slowest energy transfer) < Er < Pr < Nd (k(EnT) approximately 2 x 10(8) sec(-1), the fastest energy transfer). This order may be rationalized on the basis of the availability of excited f-f levels on the lanthanide ions at energies that overlap with the Ru-based emission spectrum. In every case, the lifetime of the lanthanide-based luminescence is short (tens/hundreds of nanoseconds, instead of the more usual microseconds), even when the water ligands on the lanthanide ions are replaced by D2O to eliminate the quenching effects of OH oscillators; we tentatively ascribe this quenching effect to the cyanide ligands.