Photophysical, spectroscopic, and computational studies of a series of Re(I) tricarbonyl complexes containing 2,6-dimethylphenylisocyanide and 5- and 6-derivatized phenanthroline ligands

The ligand 2,6-dimethylphenylisocyanide (CNx) forms six complexes of the formula [Re(CO)3(CNx)(L)]+, where L = 1,10-phenanthroline (1), 5-chloro-1,10-phenanthroline (2), 5-nitro-1,10-phenanthroline (3), 5-methyl-1,10-phenanthroline (4), 5,6-dimethyl-1,10-phenanthroline (5), and 1,10-phenanthrolinopyrrole (6). The lowest-energy absorption peaks of the complexes red-shift in the order 1 < 2 < 3 < 4 < 5 < 6. The time-dependent density functional theory (TDDFT) and conductor-like polarizable continuum model (CPCM) computed singlet excited states in ethanol deviate by 1000 cm(-1) or less from the experimental UV-vis peaks. The complexes undergo reversible reductions and irreversible oxidations. The electronic energy gap increases in the order 3 < 2 < 1 < 4 < 5 < 6, which is the order of increasing electron-donating power of the phen substituents. The reduction potentials linearly correlate with the B3LYP calculated LUMO energies for 1-6. The complexes emit at room temperature and at 77 K except 3, which emits only at 77 K. The calculated (3)MLLCT energies are within 1100 cm(-1) from the experimental emission energies at 77 K. The 77 K emission curve-fitting analysis results agree with the computational assignment of the emitting state as 3MLLCT for 1-5 and 3LC for 6. The experimental 77 K emission energies and the calculated 3MLLCT state energies increase in the order 6 < 5, 3 < 2 < 4, 1. The 77 K emission lifetimes increase upon addition of substituents from 65 micros for 1 to 171 micros for 2, to 230 micros for 4 and 5, and to 322 micros for 3. The emission quantum yields at room temperature in solution are 0.77, 0.78, 0.83, 0.56, and 0.11 for complexes 1, 2, 4, 5, and 6, respectively.     

Synthesis and properties of two new Cu(I) complexes based on 5,6-substituted imidazole-2,9-dimethyl-1,10-phenanthroline and triphenylphosphine

Two new Cu(I) complexes, Cu(NPIP)(PPh3)2 (1) and Cu(MPIP)(PPh3)2 (2), (NHPIP: 2-(4-nitrophenyl) imidazole-2,9-dimethyl-1,10-phenanthroline; MHPIP: 2-(4-methylphenyl)imidazole-2,9-dimethyl-1,10-phenanthroline) have been synthesized and characterized by element analysis, IR and ¹H NMR spectra. TG experiments demonstrated that the complexes were stable up to ca 230°C indicating their high thermal stability. According to fluorescence spectra, the complexes exhibited yellow emission at 602 nm under excitation at 260 nm.     

Cu(I)(2,9-bis(trifluoromethyl)-1,10-phenanthroline)2+ complexes: correlation between solid-state structure and photoluminescent properties

The 90K solid-state structures, room temperature absorption, and room temperature and 17 K emission spectra of seven different salts of [Cu(I)(bfp)(2)](+) (bfp = 2,9-bis(trifluoromethyl)-1,10-phenanthroline) have been determined. To quantify the distortion of the Cu coordination environment, a distortion parameter zeta is defined that is a combined measure of the flattening, rocking, and wagging distortions of the complex cations. In general, the distortion in the (bfp) cations is less than found previously for Cu(I)(dmp)(2) (dmp = 2,9-dimethyl-1,10-phenanthroline) salts, in particular the flattening is reduced because of the bulkier 2,9-substituents. The 17 K lifetimes range up to 1.8 mus in the series of solids examined and, with the marked exception of the BF(4)(-) salt, correlate linearly with the distortion parameter zeta. The emission wavelength red-shifts with decreasing lifetime, which implies that an increased ground-state distortion is associated with a smaller energy gap.     

Synthesis, characterization, and photochemical and computational investigations of Ru(II) heterocyclic complexes containing 2,6-dimethylphenylisocyanide (CNx) ligand

The isocyanide ligand forms complexes with ruthenium(II) bis-bipyridine of the type [Ru(bpy)(2)(CNx)Cl](CF(3)SO(3)) (1), [Ru(bpy)(2)(CNx)(py)](PF(6))(2) (2), and [Ru(bpy)(2)(CNx)(2)](PF(6))(2) (3) (bpy = 2,2'-bipyridine, py = pyridine, and CNx = 2,6-dimethylphenylisocyanide). The redox potentials shift positively as the number of CNx ligands increases. The metal-to-ligand charge-transfer (MLCT) bands of the complexes are located at higher energy than 450 nm and blue shift in proportion to the number of CNx ligands. The complexes are not emissive at room temperature but exhibit intense structured emission bands at 77 K with emission lifetimes as high as 25 micros. Geometry optimization of the complexes in the singlet ground and lowest-lying triplet states performed using density functional theory (DFT) provides information about the orbital heritage and correlates with X-ray and electrochemical results. The lowest-lying triplet-state energies correlate well with the 77 K emission energies for the three complexes. Singlet excited states calculated in ethanol using time-dependent density functional theory (TDDFT) and the conductor-like polarizable continuum model (CPCM) provide information that correlates favorably with the experimental absorption spectra in ethanol.     

Theoretical characterization of a typical hole/exciton-blocking material bathocuproine and its analogues

The structural, electronic, and carrier transport properties of bathocuproine (BCP), which is a typical hole/exciton-blocking material applied in organic light-emitting diodes (OLEDs), have been investigated based on density functional theory (DFT) and ab initio HF method. The detail characterizations of frontier electronic structure and lowest-energy optical transitions have been studied by means of time-dependent density functional theory (TD-DFT). Five BCP analogues, o-phenanthroline (1), 2,9-dimethyl-1,10-phenanthroline (2), 2,9-diphenyl-1,10-phenanthroline (3), 4,7-diphenyl-1,10-phenanthroline (4), and 2,9-bis(trifluoromethyl)-1,10-phenanthroline (5) have also been studied in order to select more suitable candidates of efficient hole-blocking materials. The calculated results showed that rigid planar structures, conjugate degrees, and substitute groups play crucial roles in the hole/exciton-blocking and electron-transport properties of these materials. The calculated geometries, ionization energies (IP), and energy gap between the singlet ground state and triplet excited state (E(T1)) were well in agreement with the experimental results. On the basis of the incoherent transport model, the calculated electron mobility of BCP is 1.79 x 10(-2) cm(2)/(V s), which is comparable to experimental results of 1.1 x 10(-3) cm(2)/(V s). The electron mobilities for compounds 1, 4, and 5 are 3.45 x 10(-2), 2.90 x 10(-2), and 1.40 x 10(-2) cm(2)/(V s), respectively. The calculated results indicated that compounds 1, 4, and 5 may be more effective hole/exciton-blocking materials than BCP.     

Aerobic oxidation of primary alcohols catalyzed by copper complexes of 1,10-phenanthroline-derived ligands

Five copper complexes [(L(1))(2)Cu(H(2)O)](ClO(4))(2) (1), [(L(1))Cu(H(2)O)(3)](ClO(4))(2) (1a), [(L(3))(2)Cu(H(2)O)](ClO(4))(2) (2), [(L(5))(2)Cu(H(2)O)](ClO(4))(2) (3) and [(L(6))(2)Cu](ClO(4)) (4) (where L(1) = 1,10-phenanthroline, L(3) = 1,10-phenanthroline-5,6-dione, L(5) = 1,10-phenanthrolinefuroxan and L(6) = 2,9-dimethyl-1,10-phenanthrolinefuroxan), and in situ prepared copper complexes of 2,9-dimethyl-1,10-phenanthroline (L(2)) or 2,9-dimethyl-1,10-phenanthrolinedione (L(4)) were used for aerial oxidation of primary alcohols to the corresponding aldehydes under ambient conditions. The copper catalysts have been found to catalyze a series of primary alcohols including one secondary alcohol with moderate turnover numbers and selectivity towards primary alcohols. Copper(ii) complexes 1 (or 1a) and 2 were found to be the better catalysts among all other systems explored in this study. A copper(ii)-superoxo species is implicated to initiate the oxidation reaction. Structural and electronic factors of 1,10-phenanthroline-based ligands affecting the catalytic results for aerial oxidation of alcohols are 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.     

Synthesis, characterization, crystal structure, and electrochemical, photophysical, and protein-binding properties of luminescent rhenium(I) diimine indole complexes

We report the synthesis, characterization, and photophysical and electrochemical properties of a series of luminescent rhenium(I) diimine indole complexes, [Re(N-N)(CO)3(L)](CF3SO3) (N-N = 3,4,7,8-tetramethyl-1,10-phenanthroline (Me4-phen), L = N-(3-pyridoyl)tryptamine (py-3-CONHC2H4-indole) (1a), N-[N-(3-pyridoyl)-6-aminohexanoyl]tryptamine, (py-3-CONHC5H10CONHC2H4-indole) (1b); N-N = 1,10-phenanthroline (phen), L = py-3-CONHC2H4-indole (2a), py-3-CONHC5H10CONHC2H4-indole (2b); N-N = 2,9-dimethyl-1,10-phenanthroline (Me2-phen), L = py-3-CONHC2H4-indole (3a), py-3-CONHC5H10CONHC2H4-indole (3b); N-N = 4,7-diphenyl-1,10-phenanthroline (Ph2-phen), L = py-3-CONHC2H4-indole (4a), py-3-CONHC5H10CONHC2H4-indole (4b)), and their indole-free counterparts, [Re(N-N)(CO)3(py-3-CONH-Et)](CF3SO3) (py-3-CONH-Et = N-ethyl-(3-pyridyl)formamide; N-N = Me4-phen (1c), phen (2c), Me2-phen (3c), Ph2-phen (4c)). The X-ray crystal structure of complex 3a has also been investigated. Upon irradiation, most of the complexes exhibited triplet metal-to-ligand charge-transfer (3MLCT) (d pi(Re) --> pi*(diimine)) emission in fluid solutions at 298 K and in low-temperature glass. However, the structural features and long emission lifetimes of the Me4-phen complexes in solutions at room temperature suggest that the excited state of these complexes exhibited substantial triplet intraligand (3IL) (pi --> pi*) (Me4-phen) character. The binding interactions of these complexes to indole-binding proteins including bovine serum albumin and tryptophanase have been examined.     

Design of rhenium(I) polypyridine biotin complexes as a new class of luminescent probes for avidin

This paper describes the design of a series of luminescent rhenium(I) polypyridine biotin complexes containing different spacer-arms, [Re(N-N)(CO)3 (py-4-CH2-NH-biotin)](PF6) (py-4-CH2-NH-biotin = 4-(biotinamidomethyl)pyridine; N-N = 1,10-phenanthroline, phen (1a), 3,4,7,8-tetramethyl-1,10-phenanthroline, Me4-phen (2a), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, Me2-Ph2-phen (3a), dipyrido[3,2-f:2',3'-h]quinoxaline, dpq (4a)), [Re(N-N)(CO)3 (py-3-CO-NH-en-NH-biotin)](PF6) (py-3-CO-NH-en-NH-biotin = 3-(N-((2-biotinamido)ethyl)amido)pyridine; N-N = phen (1b), Me4-phen (2b), Me2-Ph2-phen (3b), dpq (4b)), and [Re(N-N)(CO)3 (py-4-CH2-NH-cap-NH-biotin)](PF6) (py-4-CH2-NH-cap-NH-biotin = 4-(N-((6-biotinamido)hexanoyl)aminomethyl)pyridine; N-N = phen (1c), Me4-phen (2c), Me2-Ph(2)-phen (3c), dpq (4c)). Upon irradiation, all of the rhenium(I)-biotin complexes exhibited intense and long-lived triplet metal-to-ligand charge-transfer (3MLCT) (d pi(Re) --> pi* (diimine)) emission in fluid solutions at 298 K. The interactions of these biotin-containing complexes with avidin have been studied by 4'-hydroxyazobenzene-2-carboxylic acid (HABA) assays, emission titrations, and competitive association and dissociation assays. On the basis of the results of these experiments, homogeneous assays for biotin and avidin have been designed.     

Density functional theory/time-dependent DFT studies on the structures, trend in DNA-binding affinities, and spectral properties of complexes [Ru(bpy)2(p-R-pip)]2+ (R = -OH, -CH3, -H, -NO2)

Studies on the electronic structures and trend in DNA-binding affinities of a series of Ru(II) complexes [Ru(bpy)2(p-R-pip)]2+ (bpy = 2,2-bipyridine; pip = 2-phenylimidazo[4,5-f] [1,10]-phenanthroline; R = -OH, -CH3, -H, -NO2) 1-4 have been carried out, using the density functional theory (DFT) at the B3LYP/LanL2DZ level. The electronic absorption spectra of these complexes were also investigated using time-dependent DFT (TDDFT) at the B3LYP//LanL2DZ/6-31G level. The computational results show that the substituents on the parent ligand (pip) have a significant effect on the electronic structures of the complexes, in particular, on the energies of the lowest unoccupied molecular orbital (LUMO) and near some unoccupied molecular orbitals (LUMO+x, x = 1-4). With the increase in electron-withdrawing ability of the substituent in this series, the LUMO+x (x = 0-4) energies of the complexes are substantially reduced in order, for example, epsilon(LUMO)(1) approximately epsilon(LUMO)(2) > epsilon(LUMO)(3) > epsilon(LUMO)(4), whereas the pi-component populations of the LUMO+x (x = 0-4) are not substantially different. Combining the consideration of the bigger steric hindrance of complex 2, the trend in DNA-binding affinities (K(b)) of the complexes, that is, K(b)(2) < K(b)(1) < K(b)(3) < K(b)(4) can be reasonably explained. In addition, the experimental singlet metal-to-ligand charge transfer ((1)MLCT) spectra of these complexes can be well simulated and discussed by the TDDFT calculations.     

Synthesis and structural characterization of Cu(I) and Ni(II) complexes that contain the bis[2-(diphenylphosphino)phenyl]ether ligand. Novel emission properties for the Cu(I) species

The pseudotetrahedral complexes [Cu(NN)(DPEphos)]BF(4), where DPEphos = bis[2-(diphenylphosphino)phenyl]ether and NN = 1,10-phenanthroline (1), 2,9-dimethyl-1,10-phenanthroline (2), 2,9-di-n-butylphenanthroline (3), or two dimethylcyanamides (4), and NiCl(2)(DPEphos) (5) have been synthesized and structurally characterized by X-ray crystallography and their solution properties examined by use of a combination of cyclic voltammetry, NMR spectroscopy, and electronic absorption spectroscopy. Complexes 1-4 possess a reversible Cu(II)/Cu(I) couple at potentials upward of +1.2 V versus Ag/AgCl. Compounds 1-3 exhibit extraordinary photophysical properties. In room-temperature dichloromethane solution, the charge-transfer excited state of the dmp (dbp) derivative exhibits an emission quantum yield of 0.15 (0.16) and an excited-state lifetime of 14.3 mus (16.1 mus). Coordinating solvents quench the charge-transfer emission to a degree, but the photoexcited dmp complex 2 retains a lifetime of over a microsecond in acetone, methanol, and acetonitrile.     

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.     

Exceptionally long-lived luminescence from [Cu(I)(isocyanide)2(phen)]+ complexes in nanoporous crystals enables remarkable oxygen gas sensing

We report crystalline mixed-ligand copper complexes with phenanthroline and isocyanides with almost millesecond emission lifetimes that are efficient dioxygen sensors. The oxygen sensitivity of the prototype ([Cu(CN-xylyl)(2)(dmp)]tfpb, dmp = 2,9-dimethyl-1,10-phenanthroline; CN-xylyl = 2,6-dimethylphenylisocyanide; tfpb = tetrakis(bis-3,5-trifluoromethylphenylborate) is 38 times better than that of [Ru(phen)(3)]tfpb(2) (phen = 1,10-phenanthroline).     

Synergic extraction of lanthanoids by mixtures of LIX 54 (high molecular weight beta-diketone) and bidentate neutral amines.

The synergic extraction of lanthanoids has been investigated using mixtures of high molecular weight beta-diketone, LIX 54 (HA; major component, 1-phenyl-3-isoheptyl-1,3-propanedion) and bidentate neutral ligands (S) in toluene. The distribution behavior of bidentate amines (2,2'-bipyridine (bpy), 1,10-phenanthroline (phen) and 2,9-dimethyl-1,10-phenanthroline (dmp)) was investigated and their related equilibrium constants were evaluated. The synergic effect is produced by the formation of such adduct complexes as MA3 x S. The extraction constants with LIX 54 alone and those in the presence of bidentate ligands were determined for lanthanoid-series elements.     

Tetrylenes based on 1,10-phenanthroline-containing diol: the synthesis and application as initiators of ε-caprolactone polymerization

Russian Chemical Bulletin - Treatment of 4,7-dichloro-2,9-dimethyl-1,10-phenanthroline with two equivalents of p-tert-butylphenol in the presence of К2СО3 afforded...     

对苯二甲酸根桥联的双核铬(Ⅲ)配合物的合成与磁性

以对苯二甲酸根(TPHA)为桥联配体.分别端接4.4＇-二甲基-2.2＇-联吡啶(Me 2bpy),2.9-二甲基-1.10-邻菲哕啉(Me2phen)和5-氯-1,10-邻菲哕啉(Cl-phen).合成了3种新的双核铬(Ⅲ)配合物[Cr2-(TPHA)(Me2bpy)4](NO3)4(1),[Cr2(TPHA)(Me2phen)4](NO3)4(2)和[Cr 2(TPHA)(Clphen)4](N)3)4(3).经元素分析、摩尔电导和磁性测定以及红外光谱和电子光谱等手段,推定这些配合物具有TPHA桥联双核铬(Ⅲ)结构,其中,每个铬(Ⅲ)离子处于畸变八面体配位环境.测定了配合物(1)的变温磁化率(4～300 K),其数值用最小二乘法和从自旋Hamiltonian算符(H=-2JS^1S^2)导出的磁方程拟合,求得交换积分为-2.98 cm-1,结果表明双核配合物中金属离子间存在弱的反铁磁自旋交换作用.     

Synthesis, characterization and magnetism of μ-chloranilato bi-nuclear chromium (III) complexes

Five new chloranilato-bridged binuclear chromium (III) complexes have been synthesized and identified as [Cr2(CA)L4]-(ClO4)4[L denotes 5-methyl-1,10-phenanthroline (Me-phen); 2,9-dimethyl-1, 10-phenanthroline ( Me2-phen); 5-chloro-1,10-phenanthroline(Cl-phen); diaminoethane (en) or 1,3-diaminopropane (pn)], where CA represents the dianion of chloranilic acid. Based on elemental analyses, molar conductivity and magnetic moment of room-temperature measurements, and IR and electronic spectral studies, it is proposed that these complexes have CA-bridged structures and consist of two chromium (III) ions, each in an octahedral environment. The complexes [Cr2(CA)(Me-phen)4](ClO4)4(1) and [Cr2(CA)(Me2-phen)4](ClO4)4(2) were further characterized by variable temperature (4.2-300 K) magnetic susceptibility measurements and the observed data were successfully simulated by the equation based on the spin Hamiltonian operator, , giving the exchange parameter J = -7.8 cm-1 for (1) and J= -6.5 cm*1 for (2). This result     

Etude du pouvoir inhibiteur de la 2,9-chlorométhyl-1,10-phénanthroline pour la corrosion d'un acier doux en milieu HCL 1M A 90 °C

The corrosion behaviour of mild steel in 1M HCl containing organic compounds such as: 2,2′-bipyridine (inh1), 1,10-phenanthroline (inh2), 4,4′-6,6′-tetramethyl-2,2′-bipyridine (inh3) and 2,9-chloromethyl-1,10-phenanthroline (inh4), was studied by weight loss and electrochemical polarization methods. Polarization data indicate that all tested compounds are mixed-type inhibitors affecting both cathodic and anodic processes. The inhibition efficiency of these additives increases in the order: inh3 < inh1 < inh2 < inh4. The adsorption of 2,9-chloromethyl-1,10-phenanthroline on the mild steel surface in 1M HCl medium follows a Langmuir adsorption isotherm. The effect of temperature indicates that the inhibition efficiency of inh4 is temperature independent in the range 25 to 90 °C. The apparent activation energies in the absence and in the presence of inh4 were determined.     

Conversion of {Fe(NO)2}10 dinitrosyl iron to nitrato iron(III) species by molecular oxygen

A new {Fe(NO)(2)}(10) dinitrosyl iron complex possessing a 2,9-dimethyl-1,10-phenanthroline ligand has been prepared. This complex exhibits dioxygenase activity, converting NO to nitrate (NO(3)(-)) anions. During the oxygenation reaction, formation of reactive nitrating species is implicated, as shown in the effective o-nitration with a phenolic substrate.     

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.