Divalent osmium complexes: synthesis,characterization, strong red phosphorescence,and electrophosphorescence

We report new divalent osmium complexes that feature strong red metal-to-ligand-charge-transfer (MLCT) phosphorescence and electrophosphorescence. The general formula of the complexes is Os(II)(N-N)(2)L-L, where N-N is either a bipyridine or a phenanthroline and L-L is either a phosphine or an arsine. New polypyridyl ligands synthesized are 4,4'-di(biphenyl)-2,2'-bipyridine (15) and 4,4'-di(diphenyl ether)-2,2'-bipyridine (16), and the 1,10-phenanthroline derivatives synthesized are 4,7-bis(p-methoxyphenyl)-1,10-phenanthroline (17), 4,7-bis(p-bromophenyl)-1,10-phenanthroline (18), 4,7-bis(4'-phenoxybiphen-4-yl)-1,10-phenanthroline (19), and 4,7-bis(4-naphth-2-ylphenyl)-1,10-phenanthroline (20). 4,4'-Diphenyl-2,2'-bipyridine (21) and 4,7-diphenyl-1,10-phenanthroline (22) were also used in these studies. Strong pi-acid ligands used were 1,2-bis(diphenylarseno)ethane (23), cis-1,2-bis(diphenylphosphino)ethylene (24), and cis-1,2-vinylenebis(diphenylarsine) (25). Ligand 25 is used for the first time in these types of luminescent osmium complexes. These compounds feature strong MLCT absorption bands in the visible region and strong red phosphorescent emission ranging from 611 to 651 nm, with quantum efficiency up to 45% in ethanol solution at room temperature. Red organic light-emitting diodes (OLEDs) were successfully fabricated by doping the Os(II) complexes into blend of poly(N-vinylcarbazole) (PVK) and 2-tert-butylphenyl-5-biphenyl-1,3,4-oxadiazole (PBD). Brightness over 1400 cd/m(2) for a double-layer device has been reached, with a turn-on voltage of 8 V. The maximum external quantum efficiency was 0.64%. Commission Internationale de l'Eclairage (CIE) chromaticity coordinates (x, y) of the red electrophosphorescence from the complexes are (0.65, 0.34), which indicates pure red emission.     

Effect of heterocyclic diimine ligands with donor and acceptor substituents on the spectroscopic and electrochemical properties of Au(III) complexes

The composition, structure, and properties of a series of Au(III) complexes with heterocyclic diimine ligands [Au(N^N)Cl₂]⁺, where (N^N) = 2,2′-bipyridine (Bipy), 4,4′-dimethyl-2,2′-bipyridine (DmBipy), 2,2′-biquinoline (Bqx), 1,10-phenanthroline (Phen), 2,9-dimethyl-1,10-phenanthroline (DmPhen), and 4,7-diphenyl-1,10-phenanthroline (DphPhen), were characterized by ¹H NMR, electronic absorption, and emission spectroscopy and also by cyclic voltammetry. The influence of donor and acceptor substituents on the spectroscopic and electrochemical properties of the Au(III) complexes was revealed.     

Study of ion-association complexes used in spectrophotometric determination of iron

The following ion-association systems were investigated spectrophotometrically: Fe(2,2'-bipyridyl)(3)(Methyl Orange)(2); Fe(1,10-phenanthroline)(3)(Methyl Orange)(2); Fe(4,7-diphenyl-1,10-phenanthroline)(3)(Methyl Orange)2; Fe(1,10-phenanthroline)(3)(Benzyl Orange)2; Fe(4,7-diphenyl-1,10-phenanthroline)(3)(Benzyl Orange)(2). The molar absorptivities may be calculated with good precision on the basis of the spectra of the reacting species (iron chelate and dye anion), their stoichiometry and the degree of extraction. Analytically the most useful is the Fe(1,10-phenanthroline)(3)(Methyl Orange)(2) complex, molar absorptivity 4.83 x 10(4) 1. mole(-1) cm(-1) at 420 nm, but many metals (Co, Cu, Ni, Zn, Cd) form similar extractable complexes and interfere.     

Selective cytotoxic Pt(II) complexes of phenanthroline derivatives

A new dichloroplatinum(II) complex with 5-methyl-1,10-phenanthroline (1) has been obtained and characterized by X-ray diffraction. MTT assay was used for in vitro cytotoxicity evaluation of this complex, along with a similar complex with 4,7-diphenyl-1,10-phenanthroline (2) against normal and cancerous cell lines. Interestingly, the IC₅₀ values of the new complexes were higher for normal cells and in the case of complex 2, lower against all studied human cancer cells, in comparison with cisplatin.     

Carbonylrhodium(I) complexes with heterocyclic nitrogen compounds

Crystalline complexes of rhodium(I) of the type [Rh(CO)₂(NN)] [RhX₂-(CO)₂] (NN  2,2'-bipyridyl, 1,10-phenanthroline, 2,9-dimethyl-1,10-phenanthroline, 4,7-dipheynl-1,10-phenanthroline; X = Cl, Br) have been prepared. An ionic chain-like structure involving metal-metal interactions has been established by measurement of the reflectance spectra, absorption electronic spectra and electrical conductivities. The IR spectra have been examined over the 50–4000 cm^-1 range.     

Chemistry of osmium in N2P2Br2 coordination sphere: Synthesis,structure and reactivities

A family of three mixed-ligand osmium complexes of type [Os(PPh₃)₂(N-N)Br₂], where N-N=2,2′-bipyridine (bpy), 4,4′-dimethyl-2,2′-bipyridine (Me₂bpy) and 1,10-phenanthroline (phen), have been synthesized and characterized. The complexes are diamagnetic (low-spin d⁶, S=0) and in dichloromethane solution they show intense MLCT transitions in the visible region. The two bromide ligands have been replaced from the coordination sphere of [Os(PPh₃)₂(phen)Br₂] under mild conditions by a series of anionic ligands L (where L=quinolin-8-olate (q), picolinate (pic), oxalate (Hox) and 1-nitroso-2-naphtholate (nn)) to afford complexes of type [Os(PPh₃)₂(phen)(L)]⁺, which have been isolated and characterized as the perchlorate salt. The structure of the [Os(PPh₃)₂(phen)(pic)]ClO₄ complex has been determined by X-ray crystallography. The PPh₃ ligands occupy trans positions and the picolinate anion is coordinated to osmium as a bidentate N,O-donor forming a five-membered chelate ring. The [Os(PPh₃)₂(phen)(L)]⁺ complexes are diamagnetic and show multiple MLCT transitions in the visible region. The [Os(PPh₃)₂(N-N)Br₂] complexes show an osmium(II)–osmium(III) oxidation (−0.02 to 0.12 V vs. SCE) followed by an osmium(III)–osmium(IV) oxidation (1.31 to 1.43 V vs. SCE). The [Os(PPh₃)₂(phen)(L)]⁺ complexes display the osmium (II)–osmium (III) oxidation (0.26 to 0.84 V vs. SCE) and one reduction of phen (−1.50 to −1.79 V vs. SCE). The osmium (III)–osmium (IV) oxidation has been observed only for the L=q and L=Hox complexes at 1.38 V vs. SCE and 1.42 V vs. SCE respectively. The osmium(III) species, viz. [Os^III(PPh₃)₂(N-N)Br₂]⁺ and [Os^III(PPh₃)₂(phen)(L)]²⁺, have been generated both chemically and electrochemically and characterized in solution by electronic spectroscopy and cyclic voltammetry.     

Heteroleptic platinum(II) and palladium(II) complexes with thiacrown and diimine ligands

We wish to report the synthesis, crystal structures, spectroscopic and electrochemical properties of several new Pt(II) heteroleptic complexes containing the thiacrown, 9S3 (1,4,7-trithiacyclononane) with a series of substituted phenanthroline ligands and related diimine systems. These five ligands are 5,6-dimethyl-1,10-phenanthroline(5,6-Me₂-phen), 4,7-dimethyl-1,10-phenanthroline(4,7-Me₂-phen), 4,7-diphenyl-1,10-phenanthroline(4,7-Ph₂-phen), 2,2′-bipyrimidine(bpm), and pyrazino[2,3-f]quinoxaline or 1,4,5,8-tetraazaphenanthrene(tap). All complexes have the general formula [Pt(9S3)(N₂)](PF₆)₂ (N₂ = diimine ligand) and form similar structures in which the Pt(II) center is surrounded by a cis arrangement of the two N donors from the diimine chelate and two sulfur atoms from the 9S3 ligand. The third 9S3 sulfur in each structure forms a longer interaction with the platinum resulting in an elongated square pyramidal structure, and this distance is sensitive to the identity of the diimine ligand. In addition, we report the synthesis, structural, electrochemical, and spectroscopic properties of related Pd(II) 9S3 complex with tap. The ¹⁹⁵Pt NMR chemical shifts for the six Pt(II) complexes show a value near −3290 ppm, consistent with a cis-PtS₂N₂ coordination sphere although more electron-withdrawing ligands such as tap show resonances shifted by almost 100 ppm downfield. The physicochemical properties of the complexes generally follow the electron-donating or withdrawing properties of the phenanthroline substituents.     

Effect of ring methylation on the photophysical, photochemical and photobiological properties of cis-dichlorobis(1,10-phenanthroline)rhodium(III)Chloride

Methylated analogues of cis-dichlorobis(1,10-phenanthroline)rhodium(III)chloride (BISPHEN) have been prepared in order to increase the hydrophobicity of the parent compound, and thus create octahedral rhodium (III) complexes suitable for use as anticancer and antiviral agents that can be photoactivated. The parent complex has been shown in earlier work to be unable to cross through cell membranes. Octamethylation, as in the case of cis-dichlorobis(3,4,7,8-tetramethyl-1,10-phenanthroline)rhodium(III)chloride (OCTBP), provides enough hydrophobicity to be taken up by KB tumor cells. It also provides a higher level of ground-state association with double-stranded DNA and increases the quantum efficiency of photoaquation by greater than 10-fold, relative to BISPHEN. OCTBP forms covalent bonds to deoxyguanosine when irradiated with the nucleoside, as has been seen with the parent complex. Irradiation of OCTBP in the presence of the KB or M109 tumor cell lines using narrow-band UVB (lambda = 311 nm) irradiation initiates a considerable amount of phototoxicity. There is evidence that OCTBP acts as a prodrug (i.e. after passing through the cell membrane the metal complex is photolyzed to cis-chloro aquo OCTBP, which may be the active phototoxic agent). OCTBP and the tetramethyl analogue cis-dichlorobis(4,7-dimethyl-1,10-phenanthroline)rhodium(III)chloride (47TMBP) also show photoaquation upon excitation with visible light (lambda > 500 nm), and indeed, some phototoxicity of KB cells is observed at these wavelengths as well. This is attributed to direct population of photoactive triplet-excited states. These results, together with our earlier studies of cis-dichloro[dipyrido(3,2-a: 2',3'-c)phenazine (1,10-phenanthroline)rhodium(III)chloride (DPPZPHEN) demonstrate that such octahedral rhodium complexes are viable "photo-cisplatin" reagents.     

A simple method for estimating activation energies using the fragmentation yield: Collision-induced dissociation of iron(II)-phenanthroline complexes in an electrospray ionization mass spectrometer

The gas-phase stabilities of Fe(Phi)3(2+) complexes, where Phi represents the 1,10-phenanthroline, 5-chloro-1,10-phenanthroline, 5-methyl-1,10-phenanthroline, 3,4,7,8-tetramethyl-1,10-phenanthroline, and 4,7-diphenyl-1,10-phenanthroline ligands were investigated by collision-induced dissociation (CID) in the capillary-first skimmer region upon changing the voltage difference between the capillary and the skimmer. The loss of only one ligand from the Fe(Phi)3(2+) complexes was observed with each of the phenanthroline ligands studied. An increase in the voltage difference between the capillary and the skimmer resulted in a higher fragmentation yield as calculated from the intensity of the precursor and the fragment ion. The fragmentation yield versus capillary-skimmer voltage difference plots were evaluated by means of the Arrhenius and the Rice-Ramsperger-Kassel (RRK) model by fitting the model parameters to the experimental data. Both models yielded practically the same results. In addition, if the internal energy gained through the capillary-skimmer region is estimated correctly, the approximate value of the critical energy (activation energy) for fragmentation can be extracted from the fragmentation yield versus capillary-skimmer voltage difference plots. It was found that the gas-phase stabilities of the Fe(Phi)3(2+) complexes are nearly identical except for the more stable Fe(II)-4,7-diphenyl-1,10-phenanthroline complex. The critical energy for fragmentation was estimated to be approximately 1.2 and 0.9 eV for the Fe(II)- 4,7-diphenyl-1,10-phenanthroline, and the other complexes, respectively.     

Rhodium(I) carbonyl complexes with heterocyclic and nonheterocyclic nitrogen-donor ligands

Summary Complexes of the [Rh(N-N)(CO)₂][RhCl₂(CO)₂], [Rh(N-N)(CO)₂]BF₄ and Rh(N-N)(CO)₂Cl types where (N-N) = 2,9-dimethyl-1,10-phenanthroline (Me₂Phen), 4,7-diphenyl-1,10-phenanthroline (Ph₂Phen), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (Me₂2Ph₂Phen) or 2,2-biquinoline (biq), have been prepared and investigated. Benzidine (benz) ando-tolidine (tol) also form complexes of the first type. The complexes of the first two types behave as 11 electrolytes. While Ph₂Phen forms the four coordinate monocarbonyl Rh(Ph₂Phen)(CO)Cl complex, benzo(f)-quinoline (Q) yields the Rh(CO)₂ (Q)Cl compound. Triphenyl-phosphine and triphenylarsine react with the above complexes to form the well knowntrans-Rh(CO)ClL₂ where L = PPh₃ or AsPh₃. The i.r. and u.v.-visible spectra of the compounds are discussed.     

Anion selectivity studies on liquid membrane electrodes

Selectivity coefficients of liquid-membrane electrodes for common inorganic anions were measured in electrodes containing tris(l,10-phenanthroline)iron(II), tris(4,7-diphenyl-1,10-phenanthroline)iron(II) or tetraheptylammonium ion in nitrobenzene, and tris(4,7-diphenyl-1,10-phenanthroline)iron(II) ion in nitrobenzene, chloroform or n-amyl alcohol as the liquid membrane. With the exception of the amyl alcohol electrode, selectivity coefficients were relatively independent of membrane composition and followed a common sequence of decreasing selectivity: PF₆^?> ClO₄^?>SCN^?~I^?~BF₄^?>NO₃^?>Br^?>Cl^?. This sequence parallels the order of increasing anion hydration energy, suggesting that aqueous phase solvation energies play a predominant role in determining electrode selectivity for these ions. Time-dependent behavior of liquid-membrane electrodes on transfer between solutions containing different ions also is described. Instantaneous e.m.f. readings were used to determine selectivity coefficients.     

Chronoamperometric study and X-ray analysis of Ru(II)-pdto (1,8-bis-(2-pyridyl)-3,6-dithiaoctane) complexes with substituted 1,10-phenanthrolines

This work presents cyclic voltammetry and double potential step chronoamperometry experiments corresponding to the electrochemical reduction of the substituted 1,10-phenanthroline ligands in the coordination compounds [Ru(pdto)(1,10-phenanthroline)]Cl₂ (1), [Ru(pdto)(5,6-dimethyl-1,10-phenanthroline)]Cl₂ (2), [Ru(pdto)(4,7-diphenyl-1,10-phenanthroline)]Cl₂ (3), [Ru(pdto)(4,7-dimethyl-1,10-phenanthroline)]Cl₂ (4) and [Ru(pdto)(3,4,7,8-tetramethyl-1,10-phenanthroline)]Cl₂ (5). These studies were performed in order to evaluate the stability of the electrogenerated chemical species. An EC_i mechanism for all the complexes was proposed and the rate constant value (k₁) for the chemical coupled reaction was estimated. The stability is discussed in terms of the rate constant value (k₁) and the π*-acceptor properties.     

Allyl rhodium(III) complexes containing heterocyclic nitrogen ligands

Summary A series of hexacoordinated Rh^III complexes of general formula trans-[RhCl₂(allyl)(N-N)] (allyl = C₃H₅ or C₄H₇; N- = 1,10-phenanthroline, 2,9-dimethyl-1,10-phenanthroline, 4,7-diphenyl-1,10-phenanthroline, 2,2-bipyridine or 4,4-dimethyl-2,2-bipyridine) have been synthesized and characterized by spectroscopic methods. The complexes have an octahedral geometry with the Cl ligands coordinated in the trans positions. The catalytic activity of [RhCl₂(C₄H₇)(phen)] with respect to hydrogenation of alkenes has been investigated.     

Synergistic effect of heterocyclic bidentate amines on the extraction of thorium(IV) with 2-thenoyltrifluoroacetone

The synergistic effect on the extraction of thorium(IV) was found by the combination of 2-thenoyltrifluoroacetone (Htta) and 1,10-phenanthroline (phen) or 4,7-diphenyl-1,10-phenanthroline (dpp) as a neutral bidentate ligand. Especially in the presence of dpp (1·10^–3M) in benzene, the distribution ratio of thorium(IV) increased by a factor of about 300. Such synergistic enhancement of the extraction was ascribed to the formation of the adduct complex of Th(tta)₄(phen) and Th(tta)₄(dpp) in the organic phase. The extraction constant and the adduct formation constant were determined and discussed.     

Synthesis,characterization, and antitumor properties of ruthenium(II) anthraquinone complexes

Three new Ru(II) complexes, [Ru(dmb)₂(ipad)](ClO₄)₂ (dmb = 4,4′-dimethyl-2,2′-bipyridine, ipad = 2-(anthracene-9,10-dione-2-yl) imidazo[4,5-f][1,10]phenanthroline, 1), [Ru(dmp)₂(ipad)](ClO₄)₂ (dmp = 2,9-dimethyl-1,10-phenanthroline, 2), and [Ru(dip)₂(ipad)](ClO₄)₂ (dip = 4,7-diphenyl-1,10-phenanthroline, 3), have been synthesized and characterized. The three Ru(II) complexes intercalate with the base pairs of DNA. The in vitro antiproliferative activities and apoptosis-inducing characteristics of these complexes were investigated. The complexes exhibited cytotoxicity against various human cancer cell lines. BEL-7402 cells displayed the highest sensitivity to 1, accounted for by the greatest cellular uptake. Complex 1 was shown to accumulate preferentially in the nuclei of BEL-7402 cells and cause DNA damage and induce apoptosis, which involved cell cycle arrest and reactive oxygen species generation.     

烷氧基菲咯啉设计合成及其氮磷杂配铜光敏剂的光解水制氢性能

以功能化氮配体为导向,以4,7-二苯基-1,10-菲咯啉为原料,经季铵化、氧化、卤化和醚化合成了一类新型的2,9-二烷氧基-4,7-二苯基-1,10-菲咯啉配体5a~5e。再以Xantphos为膦配体,通过原位配位方法合成一系列氮磷杂配铜光敏剂(Cu PS A~H),在均相光解水制氢体系中研究其光敏活性。制氢结果表明,以2,9-二乙氧基为较佳取代基,Cu PS D的催化产氢总转换数(TON)可达270。在光电物理性能分析中,发现这类杂配铜配合物都有一对相似的氧化还原电位(Eoxd=-0.8 V,Ered=-1.2 V)。具有乙氧取代基的铜配合物CuPSD相对于其他取代基的铜基配合物,荧光最弱,表明乙氧基有助于提高荧光淬灭效率,增强铜光敏剂的光化学转换能力。     

烷氧基菲咯啉设计合成及其氮磷杂配铜光敏剂的光解水制氢性能

以功能化氮配体为导向,以4,7-二苯基-1,10-菲咯啉为原料,经季铵化、氧化、卤化和醚化合成了一类新型的2,9-二烷氧基-4,7-二苯基-1,10-菲咯啉配体5a~5e。再以Xantphos为膦配体,通过原位配位方法合成一系列氮磷杂配铜光敏剂（CuPS A~H）,在均相光解水制氢体系中研究其光敏活性。制氢结果表明,以2,9-二乙氧基为较佳取代基,CuPS D的催化产氢总转换数（TON）可达270。在光电物理性能分析中,发现这类杂配铜配合物都有一个相似的氧化还原电位（E^oxd=-0.8 V,E^red=-1.2 V）。具有乙氧取代基的铜配合物CuPS D相对于其他取代基的铜基配合物,荧光最弱,表明乙氧基有助于提高荧光淬灭效率,增强铜光敏剂的光化学转换能力。     

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.     

Eu(III) complex-doped PMMA having fast radiation rate and high emission quantum efficiency

Three ternary luminescent complexes, Eu (deuterated 1,3-diphenyl-1,3-propanedione)₃(1,10-phenanthroline), Eu (deuterated 1,3-diphenyl-1,3-propanedione)₃(2,2′-bipyridine), and Eu (deuterated 1,3-diphenyl-1,3-propanedione)₃ (bathophenanthroline) were synthesized using bidental oxygen and nitrogen as ligands. Luminescent polymers were fabricated by incorporating deuterated Eu(III) complexes in a poly(methyl methacrylate) matrix. Luminescent poly(methyl methacrylate) containing Eu (deuterated 1,3-diphenyl-1,3-propanedione)₃ (bathophenanthroline) exhibited relatively higher quantum yield, faster radiation rate, sharper red emission and larger stimulated emission cross-section (quantum yield 36%, radiation rate 8.6 × 10² s^?1, full width at half maximum 3.4 nm, and stimulated emission cross-section σ _p = 1.4 × 10^?20 cm²) of the PMMA matrix. The value of σ _p was the same order as the values of Nd-glass laser for practical use. Additionally, the thermal behaviors of the Eu(III) ternary complexes were studied, and the results indicated that all of them can be long-term used in high temperature environment. Prepared luminescent polymer including Eu (deuterated 1,3-diphenyl-1,3-propanedione)₃ (bathophenanthroline) showed promising results for applications in novel organic Eu(III) devices, such as high-power laser materials and optical fibers.     

Bimetallic bis(diphenylphosphino)acetylene bridged copper(I) complexes with 1,10-phenanthroline derivatives: synthesis,crystal structure,and spectroscopic characterization

A new series of bimetallic bis(diphenylphosphino)acetylene-bridged copper(I) 1,10-phenanthroline complexes, [Cu₂(dppa)₂(L)₂](BF₄)₂; L?=?1,10-phenanthroline (1); 4-methyl-1,10-phenanthroline (2); 4,7-dimethyl-1,10-phenanthroline (3); and 2,9-dimethyl-1,10-phenanthroline (4), have been prepared and characterized by spectroscopic methods. The X-ray structures of 1 and 4 were determined. The structures consist of centrosymmetric bimetallic 10-membered chair-like dimetallacycles. In 1, intermolecular C–H?π interactions result in bending of the phenanthroline ligand and sterically induced lengthening of one Cu–P bond. In 1–4, the ³¹P NMR downfield coordination shift, relative to the free ligand, correlates with the basic strength of the 1,10-phenanthroline ligands.