Five-coordinate hydrido / olefin platinum(II) complexes

Stable five-coordinate hydrido / olefin complexes of general formula [Pt(2,9-Me₂-1,10-phenanthroline)H(Cl)(olefin)] have been synthesized in high yield through oxidative addition of HCl to [Pt(2,9-Me₂-1,10-phenanthroline)(olefin)] precursors. Relevant spectroscopic features and some preliminary results concerning the reactivity of the new compounds are also reported.     

Biphasic Synthesis of Hydrogen Peroxide from Carbon Monoxide,Water, and Oxygen Catalyzed by Palladium Complexes with Bidentate Nitrogen Ligands

Effective and stable Pd catalysts for the biphasic synthesis of hydrogen peroxide from carbon monoxide, oxygen, and water [Eq. (a)] can be obtained by the right choice of bidentate nitrogen ligand. The best turnover numbers (578) for this reaction have been achieved with palladium complexes with 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline ligands.     

Spectral and photophysical properties of mono and dinuclear Pt(II) and Pd(II) complexes: An unusual emission behaviour

Eight mononuclear complexes of the formula [M(N-N)(DHB)] and two binuclear complexes of the formula [M₂(BPY)₂(THB)] where M = Pd(II) or Pt(II), N-N = 2,2′-bipyridine (BPY), 2,2′-biquinoline (BIQ), 4,7-diphenyl-1,10-phenanthroline (DPP), 1,10-phenanthroline (PHEN); DHB = dianion of 3,4-dihydroxybenzaldehyde and THB = tetraanion of 3,3′,4,4′-tetrahydroxy benzaldazine were prepared and their electrochemical, spectral and photophysical properties were examined. These complexes were characterized by chemical analysis, IR and proton NMR spectroscopy. A detailed study on the absorption spectroscopy of these complexes was made. These complexes were found to show a low-energy solvatochromic ligand-to-ligand charge-transfer (LLCT) band. The electronic energies of these bands have been analyzed and compared with electrochemical data. Emission behaviour of the complexes of the series, [Pt(N-N)(DHB)], [Pt(N-N)(DHBA)] where DHBA is the dianion of 3,4-dihydroxybenzoic acid and [Pt₂(BPY)₂(THB)] was also investigated. These platinum complexes were found to emit from a low-energy state at low temperature and a high-energy state at room temperature. Photophysics of these complexes is also discussed.     

Photobehavior of (alpha-diimine)dimesitylplatinum(II) complexes

The photobehavior of complexes of the type Pt(diimine)(mes)2 is investigated (where diimine = 2,2'-bipyridine (bpy), 1,10-phenanthroline (phen), 3,4,7,8-tetramethyl-1,10-phenanthroline (tmp), 2,9-dimethyl-1,10-phenanthroline (2,9-dmp), 5,6-dimethyl-1,10-phenanthroline (5,6-dmp), and 4,7-diphenyl-1,10-phenanthroline (dpp) and mes = the mesityl (2,4,6-trimethylphenyl) anion). For all compounds studied, solution RT emission is observed to be weak and excited-state lifetimes are found to be short (< or = 20 ns) regardless of solvent choice. Evidence is presented for energy-transfer quenching of Pt(dpp)(mes)2 luminescence in toluene by dissolved O2 (primarily producing singlet oxygen) with an observed quenching rate constant of kq > or = 1.3 x 10(9) M-1 s-1. Electron-transfer quenching is also observed in the presence of 3,5-dinitrobenzonitrile, yielding a quenching rate constant of kq > or = 1.6 x 10(9) M-1 s-1. The latter observation suggests that phase Pt(II) systems may have future value as excited-state reductants. All of the complexes display a much more intense and longer-lived luminescence in the solid state at room temperature. Several possible explanations for this dependence on phase are proposed, with the most probable mechanism involving radiationless deactivation in solution via rotation of the o-methyl groups of the mesityl ligands.     

Experimental and quantum-chemical studies of 1H, 13C and 15N NMR coordination shifts in Pd(II) and Pt(II) chloride complexes with methyl and phenyl derivatives of 2,2'-bipyridine and 1,10-phenanthroline

1H, 13C and 15N NMR studies of platinide(II) (M=Pd, Pt) chloride complexes with methyl and phenyl derivatives of 2,2'-bipyridine and 1,10-phenanthroline [LL=4,4'-dimethyl-2,2'-bipyridine (dmbpy); 4,4'-diphenyl-2,2'-bipyridine (dpbpy); 4,7-dimethyl-1,10-phenanthroline (dmphen); 4,7-diphenyl-1,10-phenanthroline (dpphen)] having a general [M(LL)Cl2] formula were performed and the respective chemical shifts (delta1H, delta13C, delta15N) reported. 1H high-frequency coordination shifts (Delta1Hcoord=delta1Hcomplex-delta1Hligand) were discussed in relation to the changes of diamagnetic contribution in the relevant 1H shielding constants. The comparison to literature data for similar [M(LL)(XX)], [M(LL)X2] and [M(LL)XY] coordination or organometallic compounds containing various auxiliary ligands revealed a large dependence of delta1H parameters on inductive and anisotropic effects. 15N low-frequency coordination shifts (Delta15Ncoord=delta 15Ncomplex-delta15Nligand) of ca 88-96 ppm for M=Pd and ca 103-111 ppm for M=Pt were attributed to both the decrease of the absolute value of paramagnetic contribution and the increase of the diamagnetic term in the expression for 15N shielding constants. The absolute magnitude of Delta15Ncoord parameter increased by ca 15 ppm upon Pd(II)-->Pt(II) transition and by ca 6-7 ppm following dmbpy-->dmphen or dpbpy-->dpphen ligand replacement; variations between analogous complexes containing methyl and phenyl ligands (dmbpy vs dpbpy; dmphen vs dpphen) did not exceed+/-1.5 ppm. Experimental 1H, 13C, 15N NMR chemical shifts were compared to those quantum-chemically calculated by B3LYP/LanL2DZ+6-31G**//B3LYP/LanL2DZ+6-31G*, both in vacuo and in DMSO or DMF solution.     

Synthesis and characterization of manganese(II), nickel(II), copper(II) and zinc(II) Schiff-base complexes derived from 1,10-phenanthroline-2,9-dicarboxaldehyde and 2-mercaptoethylamine

The synthesis of a new Schiff base containing 1,10-phenanthroline-2,9-dicarboxaldehyde and 2-mercaptoethylamine is described. The reaction of 1,10-phenanthroline-2,9-dicarboxaldehyde with 2-mercaptoethylamine leads to 2,9-bis(2-ethanthiazolinyl)-1,10-phenanthroline (I) which undergoes rearrangement when reacted with manganese, nickel, copper or zinc ions to produce complexes of the tautomeric Schiff base 2,9-bis[2-(2-mercaptoethyl)-2-azaethene]-1,10-phenanthroline (L). The [M(L)Cl₂] complexes [where M = Mn(II), Ni(II), Cu(II) and Zn(II) ions] were characterized by physical and spectroscopic measurements which indicated that the ligand is a tetradentate N₄ chelating agent.     

1H, 13C, 195Pt and 15N NMR structural correlations in Pd(II) and Pt(II) chloride complexes with various alkyl and aryl derivatives of 2,2'-bipyridine and 1,10-phenanthroline

(1)H, (13)C, (195)Pt and (15)N NMR studies of platinide(II) (M = Pd, Pt) chloride complexes with such alkyl and aryl derivatives of 2,2'-bipyridine and 1,10-phenanthroline as LL = 6,6'-dimethyl-bpy, 5,5'-dimethyl-bpy, 4,4'-di-tert-butyl-bpy, 2,9-dimethyl-phen, 2,9-dimethyl-4,7-diphenyl-phen, 3,4,7,8-tetramethyl-phen, having the general [M(LL)Cl(2)] formula were performed and the respective chemical shifts (δ(1H), δ(13C), δ(195Pt), δ(15N)) reported. (1)H high-frequency coordination shifts (Δ(coord)(1H) = δ(complex)(1H)-δ(ligand)(1H)) mostly pronounced for nitrogen-adjacent protons and methyl groups in the nearest adjacency of nitrogen, as well as (15)N low-frequency coordination shifts (Δ(coord)(15H) = δ(complex)(15H)-δ(ligand)(15H)) were discussed in relation to the molecular structures.     

Synthesis of transition metal complexes containing a Schiff base ligand derived from 1,10-phenanthroline-2,9-dicarboxaldehyde and 2-aminobenzenethiol

The synthesis of a new Schiff base containing 1,10-phenanthroline-2,9-dicarboxaldehyde and 2-aminobenzenethiol subunits is described. The reaction of 1,10-phenanthroline-2,9-dicarboxaldehyde with 2-aminobenzenethiol leads to the isolation of 2,9-bis(2-benzothiazolinyl)-1,10-phenanthroline (I) which undergoes rearrangement when reacted with cobalt, nickel, copper or zinc ions to produce complexes of the tautomeric Schiff base 2,9-bis[2-(2-mercaptophenyl)-2-azaethene]-1,10-phenanthroline (L). The [Cu(L)ClO₄][ClO₄] and [M(L)X₂] complexes (where M = Co(II), Ni(II) and Zn(II) and X = Br) were characterized by physical and spectroscopic measurements which indicated that the ligand is acting probably as a tetradentate N₄ chelating agent.     

A DFT study of transition metal complexes with 1,10-phenanthroline,C-C-dimeric 2,2′-bi-1,10-phenanthroline,and its tetraaza chromophore anion

Quantum-chemical calculations of the 1,10-phenanthroline complexes [M(en)(1,10-phen)]²⁺ (M = Pt, Pd, Ni; en = NH₂C₂H₄NH₂) were performed by the DFT B3LYP method in the 6-31G** basis set using the GAMESS-2006 program package. The calculations were also performed for the nickel complexes with 2,2′-bi-1,10-phenanthroline, [Ni(2,2′-bi-1,10-phen)]²⁺, and with its electron-excessive analog, [Ni(2,2′-bi-1,10-phen)]⁰, and also for the octahedral complex cation [Ni(2,2′-bi-1,10-phen)Cl(H₂O)]⁺ characterized by single crystal X-ray diffraction. For the Ni(II) complexes, the stabilities of their high-and low-spin isomers were evaluated, and the structural features were revealed. The barriers to mutual transformations of the low-and high-spin Ni(II) complexes are low.     

Synthesis,Characterization and Third-Order Nonlinear Optical Properties of a Series of Ruthenium(II) Complexes Containing 2-Arylimidazo-[4,5- f ][1,10]Phenanthroline

Three novel mononuclear ruthenium(II) complexes [Ru(dmp) 2 L] 2+ [dmp = 2,9-dimethyl-1,10-phenanthroline, L = 2-phenylimidazo-[4,5- f ][1,10]phenanthroline (PIP), 2-(4'-hydroxyphenyl)imidazo-[4,5- f ][1,10]phenanthroline (HOP), 2-(4'-dimethylaminophenyl)imidazo-[4,5- f ][1,10]phenanthroline (DMNP)] were synthesized and characterized by ES-MS, 1 H NMR, UV-Vis and electrochemistry. The nonlinear optical (NLO) properties of the ruthenium(II) complexes were investigated by Z -scan techniques with 12 ns laser pulses at 540 nm, and all of them exhibit both NLO absorption and self-defocusing effects. The corresponding effective NLO susceptibility | h 3 | of the complexes is in the range of 5.15 2 10 m 12 m 6.34 2 10 m 12 esu.     

Four- and five-coordinate palladium(II) complexes containing 1,10-phenanthroline and its 2,9-dimethyl derivative

A series of potentially five-coordinate Pd(II) complexes, [Pd(PMe₂Ph)₃(2,9-R₂-phen)][BF₄]₂ (R = H or Me; phen = 1,10-phenanthroline     

The promoting effect of chelating ligands in the oxidative carbonylation of phenol to diphenyl carbonate catalyzed by Pd–Co–benzoquinone system

The system Pd(OAc)₂/BQ/Co(acac)₃ (BQ=benzoquinone), in combination with tetrabutylammonium bromide (TBAB) as a surfactant agent and a chelating ligand such as 2,9-dimethyl-1,10-phenanthroline (dmphen) or 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (dmdpphen), is an efficient catalyst for the oxidative carbonylation of phenol to diphenyl carbonate (DPC). The best results have been obtained using the system Pd(OAc)₂/BQ/Co(acac)₃/dmphen=1/30/8/5 (molar ratio) in which [Pd]=10⁻³ mol l⁻¹ and TBAB/Pd=60/1. This system gives the maximum productivity of 700 mol DPC/mol Pd h at 135°C and under P_tot=60 atm (CO/O₂=10/1 molar ratio). The role of each component of the catalytic system is discussed and a catalytic cycle is proposed.     

Long-lived palladium catalysts for CO/vinyl arene polyketones synthesis: a solution to deactivation problems

A series of cationic palladium complexes of general formula [Pd(Me)(MeCN)(N-N)][PF(6)] (N-N = (phen) 1 a, 4,7-dichloro-1,10-phenanthroline (4,7-Cl(2)-phen) 2 a, 4,7-diphenyl-1,10-phenanthroline (4,7-Ph(2)-phen) 3 a, 4-methyl-1,10-phenanthroline (4-Me-phen) 4 a, 4,7-dimethyl-1,10-phenanthroline (4,7-Me(2)-phen) 5 a, 5,5,6,6-tetrafluoro-5,6-dihydro-1,10-phenanthroline (F(4)-phen) 6 a, containing different substituted phenanthroline ligands, have been prepared from the corresponding neutral chloro derivatives [Pd(Me)(Cl)(N-N)], (1 b-6 b). The X-ray crystal structure of [Pd(Cl)(2)(4,7-Cl(2)-phen)] (2 b') was determined. DFT calculations show that the electron density on the metal is tuned by the substituents on the ligands. The catalytic behavior of complexes 1 a-6 a in the CO/styrene and CO/p-Me-styrene copolymerizations was studied in detail, showing that the generated catalysts are active for at least 90 h, yielding copolymers of high molecular weight. A firm correlation between the electron density on palladium on the one hand and the catalytic activity of the complexes and the molecular weight and the stereochemistry of the polyketones synthesized on the other hand has been established: the catalyst containing the F(4)-phen is thus far the most active among those tested, yielding the syndiotactic CO/styrene copolymer with a stereoregularity of 96 % (uu triad) and with an M(w) value of 1 000 000.     

New water-soluble platinum(II) phenanthroline complexes tested as cisplatin analogues: First-time comparison of cytotoxic activity between analogous four- and five-coordinate species

Four- and five-coordinate platinum(II) complexes, cis-[PtCl2(A2)] (1) and [PtCl2(A2)(eta2-ethylene)] (2) {A2 = 4,7-diphenyl-1,10-phenanthroline disulfonic acid disodium salt, BPS (mixture of isomers) (a); 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline disulfonic acid disodium salt, BCS (mixture of isomers) (b)} have been synthesized and characterized by 1H, 13C, and 195Pt NMR spectroscopy. The stability and high water solubility of complexes 1a, 1b and 2b, due to the presence of the polar SO3- groups on the ligands skeleton, allowed to test their in vitro cytotoxicity on HeLa tumour cells in a wide range of drug concentration. At low and medium incubation doses (<200 microM) 1a, 1b and 2b all showed similar in vitro cytotoxicity, negligible or much lower with respect to cisplatin. At doses higher than 200 microM their activity increased and 1b, the most active among the new complexes, exhibited a cytotoxicity comparable, although still lower, with respect to cisplatin. GFAAS Platinum analytical data showed that the tested compounds 1a, 1b and 2b, although carrying sulfonate charged groups, may undergo cellular uptake, which, in the case of 1b and 2b, is even higher with respect to cisplatin. Furthermore, in the case of 1b and 2b it has been possible to compare, for the first time, the cytotoxic activity for square-planar four-coordinate and trigonal-bipyramidal five-coordinate platinum(II) complexes having the same carrier ligand. The tendency of the five-coordinate species 2b to give at longer incubation time similar cytotoxicity with respect to the square-planar compound 1b suggests a possible use of the trigonal-bipyramidal five-coordinate complexes as prodrugs.     

Rhodium and platinum complexes as catalysts for the polymerization of phenylacetylene

In polymerization reactions of phenylacetylene three different types of polyphenylacetylene (PPA) were prepared by using Rh and Pt complexes as catalysts in different reaction conditions. Type I PPA is obtained with [Rh (COD) Chel] PF₆ complexes (COD = cis,cis-cycloocta 1,5-diene; chel = 2,2′-bipyridine, 1,10-phenanthroline, 2,9-dimethyl-1,10-phenanthroline, 5,6-dimethyl-1,10-phenanthroline, 3,4,7,8-tetramethyl-1,10-phenanthroline) in bulk, benzene methanol, while type II PPA is obtained with the same catalysts in p-dioxane and type III PPA in the presence of [Pt (? C?CPh)₂(PPh₃)₂] in bulk. Type I, II, and III PPA exhibit different IR and ¹H-NMR spectra, which have been compared with literature data. Correlations proposed by different Authors between spectral properties of PPA and chain structures are also discussed.     

Copper(II)-mediated oxidative transformation of vic-dioxime to furoxan: evidence for a copper(II)-dinitrosoalkene intermediate

The mononuclear copper(II) complex [Cu(H(2)L(1))(2)(H(2)O)](ClO(4))(2) (1) (where H(2)L(1) = 1,10-phenanthroline-5,6-dioxime) reacts with copper(II) perchlorate in acetonitrile at ambient conditions in the presence of triethylamine to afford a copper(II) complex, [Cu(L(3))(2)(H(2)O)](ClO(4))(2) (2a), of 1,10-phenanthroline furoxan. A similar complex [Cu(L(3))(2)Cl](ClO(4)) (2) is isolated from the reaction of H(2)L(1) with copper(II) chloride, triethylamine, and sodium perchlorate in acetonitrile. The two-electron oxidation of the vic-dioxime to furoxan is confirmed from the X-ray single crystal structure of 2. An intermediate species, showing an absorption band at 608 nm, is observed at -20 °C during the conversion of 1 to 2a. A similar blue intermediate is formed during the reaction of [Cu(HDMG)(2)] (H(2)DMG = dimethylglyoxime) with ceric ammonium nitrate, but H(2)DMG treated with ceric ammonium nitrate does not form any intermediate. This suggests the involvement of a copper(II) complex in the intermediate step. The intermediate species is also observed during the two-electron oxidation of other vic-dioximes. On the basis of the spectroscopic evidence and the nature of the final products, the intermediate is proposed to be a mononuclear copper(II) complex ligated by a vic-dioxime and a dinitrosoalkene. The dinitrosoalkene is generated upon two-electron oxidation of the dioxime. The transient blue color of the dioxime-copper(II)-dinitrosoalkene complex may be attributed to the ligand-to-ligand charge transfer transition. The intermediate species slowly decays to the corresponding two-electron oxidized form of vic-dioxime, i.e. furoxan and [Cu(CH(3)CN)(4)](ClO(4)). The formation of two isomeric furoxans derived from the reaction of an asymmetric vic-dioxime, hexane-2,3-dioxime, and copper(II) perchlorate supports the involvement of a dinitrosoalkene species in the intermediate step. In addition, the oxidation of 2,9-dimethyl-1,10-phenanthroline-5,6-dioxime (H(2)L(2)) to the corresponding furoxan and subsequent formation of a copper(I) complex [Cu(L(4))(2)](ClO(4)) (3) (where L(4) = 2,9-dimethyl-1,10-phenanthroline furoxan) are discussed.     

DNA binding and biological activity of some platinum(II) intercalating compounds containing methyl-substituted 1,10-phenanthrolines

This study documents the first detailed investigation into the relationship between molecular structure and biological activity of platinum(II) complexes containing methylated derivatives of 1,10-phenanthroline (phen). A series of square planar platinum(II) compounds incorporating methylated derivatives of phen, 4-methyl-1,10-phenanthroline (4-Mephen), 5-methyl-1,10-phenanthroline (5-Mephen), 4,7-dimethyl-1,10-phenanthroline (4,7-Me2phen), 5,6-dimethyl-1,10-phenanthroline (5,6-Me2phen) and 3,4,7,8-tetramethyl-1,10-phenanthroline (3,4,7,8-Me4phen) were synthesised and the relationship between their structure and biological activity investigated. The biological activity of these compounds was quantified using the in vitro cytotoxicity assay against the L1210 Murine leukaemia cell line. Large variation in cytotoxicities with different methylation was observed. The 5- and 5,6-methylated derivatives of phen displayed a greater biological activity, with IC50 values of 2.8 +/- 0.8 microM and 1.5 +/- 0.3 microM respectively, compared with the phen compound, with an IC50 value of 9.7 +/- 0.3 microM, while all the others were inactive with IC50 values over 50 microM. Binding constants were determined using circular dichroism spectroscopy (CD) and induced circular dichroism (ICD). ICD was used to highlight any differences in the spectra. Viscometry studies and linear dichroism (LD) experiments indicate that the platinum(II) complexes intercalate although for [Pt(en)(4-Mephen)]Cl2 and [Pt(en)(4,7-Me2phen)]Cl2 this mode of binding appears to be concentration dependent. The binding of the platinum(II) complexes to the oligonucleotide d(GTCGAC)2 was studied using two-dimensional 1H NMR spectroscopy. The addition of each metal complex to the hexamer d(GTCGAC)2 produced upfield shifts of the metal complex resonances, characteristic of intercalation. Through the observation of NOE cross-peaks, two-dimensional NMR studies provided insight into the site and groove preferences of these compounds when binding to DNA.     

1H n.m.r. studies of palladium(II) complexes of 2,9-dimethyl-1,10-phenanthroline and 8-hydroxyquinoline

Summary The structures in solution of a series of palladium(II) complexes have been determined by¹H n.m.r. and i.r. spectroscopy. Dicyanobis-(8-hydroxyquinoline)palladium(II) has acis-square-planar configuration, the unidentate 8-hydroxyquinoline molecules bonding to Pd through the nitrogen atoms. Dicyanobis-(2,9-dimethyl-1,10-phenanthroline)-palladium(II) has acis-square planar arrangement about Pd with respect to the nitrogen atoms of the two heterocyclic ligands. The cyanide groups bond to the two apical positions apparently giving rise to a six-coordinate PdlI atom. Dihalo-2,9-dimethyl-1,10-phenanthrolinepalladium(II) (X = Cl, Br, I) exhibits the usualcis-square-planar arrangement of Pd^II, whereas the halobis-(2,9-dimethyl-1,10-phenanthroline) - palladium(II) ion (X = Cl, Br) has a trigonal bipyramidal structure with the halogen atom in the trigonal plane.     

Spectral and electrochemical studies of bis(diimine)copper(II) complexes in anionic, cationic and nonionic micelles

The spectral and redox behavior of bis(diimine)copper(II) complexes, where diimine is bipyridine, 1,10-phenanthroline, 4-methyl-1,10-phenanthroline, 5-methyl-1,10-phenanthroline, 5-nitro-1,10-phenanthroline, 4,7-dimethyl-1,10-phenanthroline, 5,6-dimethyl-1,10-phenanthroline, 2,9-dimethyl-1,10-phenanthroline, 3,4,7,8-tetramethyl-1,10-phenanthroline and dipyrido-[3,2-d:2',3'-f]-quinoxaline, are significantly different in aqueous and in aqueous SDS, CTAB and Triton X-100 micellar solutions. The (1)H NMR spectral study in aqueous (D(2)O) and aqueous micelles reveals that the Cu(II) complexes interact more strongly with SDS than with CTAB and Triton X-100 micelles and at sites on SDS micelles different from those on the latter. Ligand Field spectral studies reveal that the complexes exist as the dicationic aquated species [Cu(diimine)(2)(H(2)O)(2)](2+), which interacts strongly with the anionic SDS micelles through columbic forces. However, they exist as [Cu(diimine)(2)(H(2)O)Cl](+) and/or [Cu(diimine)(2)H(2)] located in the hydrophobic microenvironments in Triton X-100 and CTAB micelles. The attainment of reversibility of the redox systems in the micellar microenvironments is remarkable and this illustrates that the Cu(II) and Cu(I) species undergo stereochemical changes suitable for reversible electron-transfer. The remarkable differences in spectral and electrochemical properties of Cu(II) complexes in aqueous and aqueous micellar solutions illustrate that the complexes are nestled largely within the micellar environments and imply that the accessibilities of the complexes to electron-transfer are different and are dependent on the nature of micelles as well as the nature and hydrophobicity of the diimine ligands.     

Highly luminescent bis-diketone lanthanide complexes with triple-stranded dinuclear structure

A new bis-β-diketone, 3,3'-bis(4,4,4-trifluoro-1,3-dioxobutyl)biphenyl (BTB), has been designed and prepared for the synthesis of a series of dinuclear lanthanide complexes [Ln(2)(BTB)(3)(C(2)H(5)OH)(2)(H(2)O)(2)] [Ln = Eu (1), Gd (2)], [Ln(2)(BTB)(3)(DME)(2)] [Ln = Nd (3), Yb (4); DME = ethylene glycol dimethyl ether] and [Eu(2)(BTB)(3)(L)(2)] [L = 2,2-bipydine (5); 1,10-phenanthroline (6); 4,7-diphenyl-1,10-phenanthroline (7)]. Complexes 1-7 have been characterized by various spectroscopic techniques and their photophysical properties are investigated. X-ray crystallographical analysis reveals that complexes 1, 3 and 4 adopt triple-stranded dinuclear structures which are formed by three bis-bidentate ligands with two lanthanide ions. The complexes 1 and 3-7 display strong visible red or NIR luminescence upon irradiation at ligand band around 372 nm, depending on the choice of the lanthanide. The solid-state photoluminescence quantum yields and the lifetimes of Eu(3+) complexes are determined and described.