Syntheses and structural characterization of dicopper(I) bis(diphenylphosphino)acetylene complexes containing tricyclic, cyclic and linear frameworks

The complexes [Cu₂(dppa)₃(CH₃CN)₂][BF₄]₂ (1) and Cu₂(dppa)₃(O₃SCF₃)₂ (2) have been prepared in good yields by treating [Cu(MeCN)₄][BF₄] and [Cu(MeCN)₄][O₃SCF₃], respectively, with Ph₂PCCPPh₂ (abbreviated as dppa) at room temperature. The reaction of 1 with di-2-pyridyl ketone (abbreviated as dpyk) produces [Cu₂(dppa)₂(dpyk)₂][BF₄]₂ (3), and with 1,1′-bis(diphenylphosphino)ferrocene (abbreviated as dppf) produces [Cu₂(dppa)(dppf)₂][BF₄]₂ (4). The molecular structures of 1-4 have been determined by an X-ray diffraction study. Compounds 1 and 2 form a helical Cu₂(dppa)₃ metallatricycle, compounds 3 forms a Cu₂(dppa)₂ metallacycle, and compound 4 contains a linear Cu₂(dppa) skeleton.     

Syntheses and characterization of luminescent dinuclear and polynuclear Cu(I) complexes containing 4,4′-bis(diphenylphosphino)biphenylene bridge

The dinuclear complex [Cu₂(dpbp)₂(NCMe)₄][BF₄]₂ (1) has been prepared by treating [Cu(NCMe)₄][BF₄] with 4,4′-bis(diphenylphosphino)biphenylene (abbreviated as dpbp). Reactions of 1 with 2,2′-bipyridine and 1,1′-bis(diphenylphosphino)ferrocene (abbreviated as dppf) afford [Cu₂(dpbp)₂(2,2′-bipy)₂][BF₄]₂ (2) and [Cu₂(dpbp)(dppf)₂][BF₄]₂ (3), respectively. In contrast, compound 1 reacts with tetra(2-pyridyl)ethyl-1,4-diaminobutane (abbreviated as tpyda) to produce the polymeric complex {[Cu₂(dpbp)(tpyda)][BF₄]₂}_n (4). Compounds 1-4 are photoluminescent with the emission band (λ_max) in the range 510-554 nm. The crystal structures of 1 and 4 have been determined by an X-ray diffraction study.     

Communication of metal ions in the dinuclear ruthenium complexes containing 4,4′-bipyridine, 1,4-diisocyanobenzene, and pyrazine bridging ligands: Synthesis, characterization and structure determination

Reaction of [Ru(2,2′-bipyridine)(2,2′:6′,2″-terpyridine)Cl]PF₆ (abbreviated to [Ru(bipy)(terpy)Cl]PF₆) with 0.5 equiv of the bidentate ligand L produces the dinuclear complexes [{Ru(bipy)(terpy)}₂(μ-L)](PF₆)₄ (L = 4,4′-bipyridine 1, 1,4-diisocyanobenzene 2 and pyrazine 3) in moderate yields. Treating [Ru(bipy)(terpy)Cl]PF₆ with equal molar of 1,4-diisocyanobenzene affords [Ru(bipy)(terpy)(CNC₆H₄NC)](PF₆)₂ (2a). These new complexes have been characterized by mass, NMR, and UV-Vis spectroscopy, and the structures of 1-3 determined by an X-ray diffraction study. Cyclic voltammetric studies suggest that metal communication between the two ruthenium ions increases from 1 to 2 to 3.     

Reactions of rhodium(II) and iridium(III) complexes bearing a P,O-coordination with tetracyanoethylene in the presence of KPF6

Reactions of Cp*M(MDMPP-P,O)Cl (1a: M=Rh, 1b: M=Ir; MDMPP-P,O=PPh₂(2-O-6-MeOC₆H₃)) with tetracyanoethylene (tcne) in the presence of KPF₆ gave Cp*MCl[PPh₂{2-O-3-(C(CN)₂CH(CN)₂)-6-MeOC₆H₂}] (2), [{Cp*MPPh₂{2-O-3-(C(CN)C(CN)₂)-6-MeOC₆H₂}}₂(CN)](PF₆) (3), [{Cp*IrPPh₂{2-O-3-(C(CN)C(CN)₂)-6-MeOC₆H₂}}(CN){Cp*Ir(MDMPP-P,O)}](PF₆) (4b) and [{Cp*Ir(MDMPP-P,O)}₂(CN)](PF₆) (5b), depending on the reaction conditions. Reaction of 2 with KPF₆ or AgOTf in the absence and presence of xylyl isocyanide (XylNC) gave 3 or [Cp*MCl{PPh₂(2-O-3-(C(CN)₂-CH(CN)₂)-6-MeOC₆H₂)}(XylNC)](OTf) (6). The structure of 3a (M=Rh) was confirmed by X-ray crystal analysis.     

Rectangular tetranuclear silver(I) and μ8-selenide-centered octanuclear copper(I) complexes containing bis(diphenylphosphino)amide ligands

Interaction of Ag(CF₃CO₂) with bis(diphenylphosphino)amide (dppa) in THF gave a tetranuclear Ag₄-coplanar silver(I) complex [Ag₄(μ-dppa)₂(μ₄-O₂PPh₂)₂(μ-CF₃CO₂)₂] (1). The trinuclear trigonal-bipyramid copper(I) complex [Cu₃(μ₃-Cl)₂(μ-dppa)₃][CuCl₂] (2) was obtained from the reaction of [CuCl] powder with bis(diphenylphosphino)amide (dppa) in THF. Treatment of 2 with (Me₃Si)₂Se in THF afforded a μ₈-selenide-centered octanuclear copper(I) complex [Cu₈(μ₈-Se)(μ₄-Se)(μ₄-SeH)₃(μ-dppa)₄][(Ph₂PO)₂N] (3). The structures of 1-3 were determined by single-crystal X-ray diffraction analyses. Complex 1 comprises a rectangular Ag₄ array with each edge bridged with a pair of μ-dppa, μ₄-O₂PPh₂ and μ-CF₃CO₂ ligands that are approximately perpendicular to each other. Complex 2 contains a trigonal-bipyramid [Cu₃(μ₃-Cl)₂]⁺ core surrounded by three μ-dppa ligands. The cationic complex in 3 consists of four [Cu₂(μ-dppa)] fragments side-capped by one μ₄-Se and three μ₄-SeH ligands and center-connected by a μ₈-Se atom.     

Homo- and heteronuclear complexes based on arene ruthenium complexes bearing bis(diphenylphosphinomethyl)phenylphosphine (dpmp)

Reactions of [(p-cymene)RuCl₂]₂ (1a) with dpmp ((Ph₂PCH₂)₂PPh) in the absence or presence of KPF₆ afforded the ionic complexes [{(p-cymene)RuCl₂}(dpmp-P¹,P³;P²){RuCl(p-cymene)}](X) (2a₁: X=Cl; 2a₂: X=PF₆). A (p-cymene)RuCl moiety constructs a 6-membered ring coordinated by two terminal P atoms of the dpmp ligand and another one binds to a central P atom of the ligand. Reactions of [(C₆Me₆)RuCl₂]₂ (1b) with an excess of dpmp in the presence of KPF₆ gave a 4-membered complex [(C₆Me₆)RuCl(dpmp-P¹,P²)](PF₆) (3b), chelated by a terminal and a central P atom and another terminal atom is free. Use of Ag(OTf) instead of KPF₆ gave [{(C₆Me₆)RuCl₂(dpmp)Ag} ₂](OTf)₂ (5b) that the Ag atoms were coordinated by a terminal and a central P atom of each dpmp ligand. Reaction with an equivalent of dpmp in the presence of KPF₆ gave [{(C₆Me₆)RuCl}(dpmp-P¹,P²;P³){(C₆Me₆)RuCl₂}](PF₆) 4b. Complex has a structure that the (C₆Me₆)RuCl₂ moiety coordinated to the free P atom of 3b. Complex 3b was treated with MCl₂(cod) (M=Pd, Pt), [Pd(MesNC)₄](PF₆)₂ (MesNC=2,4,6-Me₃C₆H₂NC) or [Pt₂(XylNC)₆](PF₆)₂ (XylNC=2,6-Me₂C₆H₃NC), generating [{(C₆Me₆)RuCl(dpmp)}₂MCl₂](PF₆)₂ (8b: M=Pd; 9b: M=Pt), [{(C₆Me₆)RuCl(dpmp)}₂{Pt(MesNC)₂}](PF₆)₄ (10b) and [{(C₆Me₆)RuCl(dpmp)}₂{Pt₂(XylNC)₄}](PF₆)₄ (11b), respectively. Complex 3b reacted readily with [Cp*MCl₂]₂ (M=Rh, Ir) or AuCl(SC₄H₈), affording the corresponding hetero-binuclear complexes [{(C₆Me₆)RuCl}(dpmp-P¹,P²;P³)(MCl₂Cp^*](PF₆) (6b: M=Rh; 7b: M=Ir) and [{(C₆Me₆)RuCl}(dpmp-P¹,P²;P³)(AuCl)](PF₆) (12b). These complexes have two chiral centers. Some complexes were separated as two diastereomers by successive recrystallization. The structures of 3b, 5b, 6b, 8b and 12b were confirmed by X-ray analyses.     

A kinetic study on pyridine exchange reactions at a bis(μ-acetato)(μ-oxo)diruthenium(III) center: effects of monodentate and bidentate N-heterocyclic ligands cis to the oxo bridge

A series of (μ-oxo)bis(μ-acetato)diruthenium(III) complexes containing two pyridine (py) ligands and varied N-heterocyclic ligands in the positions trans and cis to μ-O, respectively, have been prepared to study py/py-d₅ exchange reactions using ¹H NMR spectroscopy. The diruthenium(III) complexes under investigation are [Ru₂(μ-O)(μ-CH₃COO)₂(py)₆](PF₆)₂ (1), [Ru₂(μ-O)(μ-CH₃COO)₂(bpy)₂(py)₂](PF₆)₂ (2), [Ru₂(μ-O)(μ-CH₃COO)₂(acpy)₄(py)₂](FF₆)₂ (3), and [Ru₂(μ-O)(μ-CH₃COO)₂(dmbpy)₂(py)₂](PF₆)₂ (4), where bpy=2,2′-bipyridine, acpy=4-acetylpyridine, and dmbpy=4,4′-dimethyl-2,2′-bipyridine. Pseudo-first order rate constants for the ligand-exchange reactions are 10⁻⁶−10⁻⁵ s⁻¹ for 1-4 in CD₃CN at 298 K. It is found that the rate of the py/py-d₅ exchange reactions is controlled by the electronic nature of the cis-oriented ancillary ligands, while the exchange mechanisms are tuned principally by the ligand steric factors. The activation parameters (ΔH^‡ and ΔS^‡) indicate that exchange reactions proceed through the dissociative (D) or the interchange dissociative (I_d) mechanism for 1 and 3. Negative ΔS^‡ values observed for 2 and 4 suggest a significant contribution of incoming ligands to the exchange pathway. The kinetic and thermodynamic parameters for the diruthenium series and the corresponding data for Ru-based oxo bridged trinuclear complexes established previously are compared and discussed.     

Aerobic oxygenation of organic sulfides using diruthenium activators

Diruthenium compounds supported by carboxylate or mixed carboxylate/carbonate bridging ligands were found to be active catalysts for aerobic oxygenation of organic sulfides. Ru₂(OAc)₃(CO₃) (A), Ru₂(O₂CCF₃)₃(CO₃) (B) and Ru₂(OAc)₄Cl (C) promote the conversion of organic sulfide to sulfoxide, and subsequently sulfone in an oxygen atmosphere at ca. 90 °C. The order of catalytic activity is A > B ? C. Catalytic reactions are operative in a number of 1:1 co-solvent-H₂O combinations, and the highest reactivity was found in aqueous media.     

Multimetallic compounds containing cyclometalated Ir(III) units: Synthesis, structure, electrochemistry and photophysical properties

The reaction of the cyclometalated Ir^III dimer [{(ppy)₂Ir}₂(μ-Cl)₂] (ppyH = 2-phenylpyridine) with silver triflate followed by a multidentate ligand [1,4-bis[3-(2-pyridyl)pyrazolylmethyl]benzene (bppb), 1,3,5-tri[3-(2-pyridyl)pyrazolylmethyl]-2,4,6-trimethylbenzene (tppb), 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz), 2-chloro-4,6-bis(dipyridin-2-ylamino)-1,3,5-triazine (cddt) or 2,4,6-tris(dipyridin-2-ylamino)-1,3,5-triazine (tdat)] afforded di- or trinuclear compounds: [{Ir(ppy)₂}₂(μ-bppb)](OTf)₂ (1), [{Ir(ppy)₂}₃(μ-tppb)](OTf)₃ (2), [{Ir(ppy)₂}₂(μ-tptz-OH)](OTf) (3), [{Ir(ppy)₂}₂(μ-cddt)](OTf)₂ (4) and [{Ir(ppy)₂}₂(μ-tdat)](OTf)₂ (5). All of these compounds contain cationic metal cores with corresponding triflate counter anions. The molecular structures of 1-4 reveal that the structural feature of the Ir(ppy)₂ center of the starting precursor is conserved in the products. Also, because of the nature of the ligands, there is virtually no electronic communication between the Ir^III centers except in 3 where a ring hydroxylation at the triazine carbon atom is effected upon metalation. Compounds 1-5 are robust in solution where they retain their structural integrity. The UV-Vis and emission spectra of 1-5 compounds are very similar to each other with the exception of 3 which seems to possess a different electronic structure. All the compounds are luminescent at room temperature. The emission bands indicate significant contribution from ³LC. Increase in the number of ‘Ir(ppy)₂’ units does not have any effect on emission color.     

Synthesis and molecular structure of trinuclear mixed-metal cluster cations containing arene and hydrido ligands

The mixed-metal trinuclear cluster cations [H₃Ru₂(C₆Me₆)₂Os(C₆H₆)(O)]⁺ (1), [H₃Ru₂(1,2,4,5-C₆H₂Me₄)₂Os(p-MeC₆H₄ⁱPr)(O)]⁺ (2) and [H₃Ru₂(1,2,4,5-C₆H₂Me₄)₂Os(C₆H₆)(O)]⁺ (3) have been synthesised from the corresponding dinuclear precursors [H₃Ru₂(arene)₂]⁺ and the corresponding mononuclear complexes [Os(arene)(H₂O)₃]²⁺, isolated and characterised as the tetrafluoroborate and hexafluorophosphate salts. The cations 1, 2 and 3 are heteronuclear analogues of the cluster cation [H₃Ru₃(C₆H₆)(C₆Me₆)₂(O)]⁺ that possesses a homonuclear metallic core. The single-crystal X-ray structure analyses of [1][BF₄], [2][PF₆] and [3][PF₆] reveal an equiangular metal triangle despite the presence of an osmium atom in the metallic core.     

The synthesis, structure, and luminescence of two silver(I)-dppm complexes based on sulfate anion and nitrogen heterocyclic ligands

At ambient temperature, two silver(I) complexes [Ag₄(SO₄)₂(dppm)₄]·5CH₃CH₂OH·1/2H₂O (1) and [Ag₂(SO₄)(dppm)₂(2-ampz)]·CH₃OH·H₂O (2) (dppm = bis(diphenylphosphino)methane, 2-ampz = 2-aminopyrazine) were obtained by the reaction of Ag₂SO₄ with dppm in the presence of pyrazine or 2-aminopyrazine. They are characterized by IR, X-ray crystallography, luminescence and ¹H, ³¹P NMR spectroscopy. Complex 1 is a tetranuclear cluster. In complex 2, the units [Ag₂(SO₄)(dppm)₂] are connected by 2-aminopyrazine to form a 1D linear polymer. Due to the subtle interactions of different nitrogen heterocyclic ligands with silver ions, two SO₄²⁻ anions in 1 adopt μ₃-O, O′, O′ and unique μ₄-O, O, O′, O′ bonding modes respectively, while SO₄²⁻ anion in 2 adopts μ-O, O′ bonding mode.     

Synthesis, characterization, crystal structures and photophysical properties of copper(I) complexes containing 1,1′-bis(diphenylphosphino)ferrocene (B-dppf) in doubly-bridged mode

Five copper(I) complexes having general formula [Cu₂(μ-X)₂(κ²-P,P-B-dppf)₂] (X = Cl(1), Br(2), I(3), CN(4), and SCN(5)) were prepared starting with CuX and B-dppf in 1:1 molar ratio in DCM-MeOH (50:50 V/V) at room temperature. The complexes have been characterized by elemental analyses, IR, ¹H NMR, ³¹P NMR and electronic spectral studies. Molecular structures for 1, 2 and 4 were determined crystallographically. Complexes 1, 2 and 4 exist as centrosymmetric dimers in which the two copper atoms are bonded to two bridging B-dppf ligands and two bridging (pseudo-)halide groups in a μ-η¹ bonding mode to generate nearly planar Cu₂(μ-η¹-X)₂ framework. Both bridging B-dppf ligands are arranged in antiperiplanar staggered conformation in 1 and 2 (mean value 56.40-56.76°), and twisted from the eclipsed conformation (mean value 78.19°) in 4. The Φ angle value in 4 is relatively larger as compared to 1 and 2. This seems to indicate that the molecular core [Cu₂(μ-η¹-X)₂] in 4 is a sterically demanding system that forces the B-dppf ligand to adopt a relatively strained conformation in comparison to less strained system in 1 and 2. All the complexes exhibit moderately strong luminescence properties in the solution state at ambient temperature.     

Dicopper(II) complexes showing DNA hydrolase activity and monomeric adduct formation with bis(4-nitrophenyl)phosphate

Ferromagnetic dicopper(II) complexes [Cu₂(μ-O₂CCH₃)(μ-OH)(L)₂(μ-L¹)](PF₆)₂, where L = 1,10-phenanthroline (phen), L¹ = H₂O in 1 and L = dipyrido[3,2-d:2′,3′-f]quinoxaline (dpq), L¹ = CH₃CN in 2, are prepared and structurally characterized. Crystals of 1 and 2 belong to the monoclinic space group of P2₁/n and P2₁/m, respectively. The copper(II) centers display distorted square-pyramidal geometry having a phenanthroline base and two oxygen atoms of the bridging hydroxo and acetate group in the basal plane. The fifth coordination site has weak axially bound bridging solvent molecule H₂O in 1 and CH₃CN in 2. The Cu···Cu distances are 3.034 and 3.046 Å in 1 and 2, respectively. The complexes show efficient hydrolytic cleavage of supercoiled pUC19 DNA as evidenced from the mechanistic studies that include T4 DNA ligase experiments. The binuclear complexes form monomeric copper(II) adducts [Cu(L)₂(BNPP)](PF₆) (L = phen, 3; dpq, 4) with bis(4-nitrophenyl)phosphate (BNPP) as a model phosphodiester. The crystal structures of 3 and 4 reveal distorted trigonal bipyramidal geometry in which BNPP binds through the oxygen atom of the phosphate. The kinetic data of the DNA cleavage reactions of the binuclear complexes under pseudo- and true-Michaelis-Menten conditions indicate remarkable enhancement in the DNA hydrolysis rate in comparison to the control data.     

Luminescent probes for indole-binding proteins derived from ruthenium(II) polypyridine complexes

We report here the synthesis, characterisation, electrochemical, photophysical and protein-binding properties of four luminescent ruthenium(II) polypyridine indole complexes [Ru(bpy)₂(L1)](PF₆)₂ (1), [Ru(bpy)₂(L2)](PF₆)₂ (2), [Ru(L1)₃](PF₆)₂ (1a), and [Ru(L2)₃](PF₆)₂ (2a) (bpy = 2,2′-bipyridine; L1 = 4-(N-(2-indol-3-ylethyl)amido)-4′-methyl-2,2′-bipyridine; L2 = 4-(N-(6-N-(2-indol-3-ylethyl)hexanamidyl)amido)-4′-methyl-2,2′-bipyridine). Their indole-free counterparts, [Ru(bpy)₂(L3)](PF₆)₂ (3) and [Ru(L3)₃](PF₆)₂ (3a) (L3 = 4-(N-(ethyl)amido)-4′-methyl-2,2′-bipyridine), have also been synthesised for comparison purposes. Cyclic voltammetric studies revealed ruthenium-based oxidation at ca. +1.3 V versus SCE and diimine-based reductions at ca. −1.20 to −2.28 V. The indole moieties of complexes 1, 2, 1a and 2a displayed an irreversible wave at ca. +1.1 V versus SCE. All the ruthenium(II) complexes exhibited intense and long-lived orange-red triplet metal-to-ligand charge-transfer ³MLCT (dπ(Ru) → π*(L1-L3)) luminescence upon visible-light irradiation in fluid solutions at 298 K and in alcohol glass at 77 K. The binding of the indole-containing complexes to bovine serum album (BSA) has been studied by quenching experiments and emission titrations.     

Synthesis and characterisation of bis(2,2′-bipyridine)(4-carboxy-4′-(pyrid-2-ylmethylamido)-2,2′-bipyridine)ruthenium(II) di(hexafluorophosphate): Comparison of spectroelectrochemical properties with related complexes

The new complex, [Ru^II(bpy)₂(4-HCOO-4′-pyCH₂ NHCO-bpy)](PF₆)₂ · 3H₂O (1), where 4-HCOO-4′-pyCH₂NHCO-bpy is 4-(carboxylic acid)-4′-pyrid-2-ylmethylamido-2,2′-bipyridine, has been synthesised from [Ru(bpy)₂(H₂dcbpy)](PF₆)₂ (H₂dcbpy is 4,4′-(dicarboxylic acid)-2,2′-bipyridine) and characterised by elemental analysis and spectroscopic methods. An X-ray crystal structure determination of the trihydrate of the [Ru(bpy)₂(H₂dcbpy)](PF₆)₂ precursor is reported, since it represented a different solvate to an existing structure. The structure shows a distorted octahedral arrangement of the ligands around the ruthenium(II) centre and is consistent with the carboxyl groups being protonated. A comparative study of the electrochemical and photophysical properties of [Ru^II(bpy)₂(4-HCOO-4′-pyCH₂NHCO-bpy)]²⁺ (1), [Ru(bpy)₂(H₂dcbpy)]²⁺ (2), [Ru(bpy)₃]²⁺ (3), [Ru(bpy)₂Cl₂] (4) and [Ru(bpy)₂Cl₂]⁺ (5) was then undertaken to determine their variation upon changing the ligands occupying two of the six ruthenium(II) coordination sites. The ruthenium(II) complexes exhibit intense ligand centred (LC) transition bands in the UV region, and broad MLCT bands in the visible region. The ruthenium(III) complex, 5, displayed overlapping LC bands in the UV region and a LMCT band in the visible. 1, 2 and 3 were found, via cyclic voltammetry at a glassy carbon electrode, to exhibit very positive reversible formal potentials of 996, 992 and 893 mV (versus Fc/Fc⁺) respectively for the Ru(III)/Ru(II) half-cell reaction. As expected the reversible potential derived from oxidation of 4 (−77 mV (versus Fc/Fc⁺)) was in excellent agreement with that found via reduction of 5 (−84 mV (versus Fc/Fc⁺)). Spectroelectrochemical experiments in an optically transparent thin-layer electrochemical cell configuration allowed UV-Vis spectra of the Ru(III) redox state to be obtained for 1, 2, 3 and 4 and also confirmed that 5 was the product of oxidative bulk electrolysis of 4. These spectrochemical measurements also confirmed that the oxidation of all Ru(II) complexes and reduction of the corresponding Ru(III) complex are fully reversible in both the chemical and electrochemical senses.     

Synthesis and characterization of β-diketonato ruthenium(II) complexes with two 4-bromo or protected 4-ethynyl-2,2′-bipyridine ligands

Two new mononuclear mixed-ligand ruthenium(II) complexes with acetylacetonate ion (2,4-pentanedionate, acac) and functionalized bipyridine (bpy) in position 4, [Ru(bpyBr)₂(acac)](PF₆) (2; bpyBr = 4-Bromo-2,2′-bipyridine, acac = 2,4-pentanedionate ion) and [Ru(bpyOH)₂(acac)](PF₆) (3; bpyOH = 4-[2-methyl-3-butyn-2-ol]-2,2′-bipyridine) were prepared as candidates for building blocks. The ¹H NMR, ¹³C NMR, UV-Vis, electrochemistry and FAB mass spectral data of these complexes are presented.     

Reactions of 1,8-bis(diphenylphosphino)naphthalene with ruthenium cluster carbonyls: C-H and C-P bond cleavage reactions

Reactions between Ru₃(CO)₁₂ and 1,8-bis(diphenylphosphino)naphthalene (dppn) have given the four complexes Ru₃(μ-H){μ₃-PPh₂(nap)PPh(C₆H₄)}(CO)₈ (1), Ru₄(μ-H){μ₃-PPh₂(nap)PPh(C₆H₄)}(μ-CO)₃(CO)₇ (2) and Ru₄(μ-H)(μ₃-C₆H₄){μ-PPh(nap)PPh₂}(CO)₁₁ (3) (in refluxing thf), and Ru₄{μ₄-P(nap)PPh₂}(μ₄-C₆H₄)(μ-CO)(CO)₉ (4) (in refluxing toluene) which have been characterised by single crystal X-ray studies. They have been formed by aryl C-H and aryl C-P bond cleavage reactions, presumably from an initial (unobserved) chelate dppn complex. The unchanged chelating ligand is found in Ru₃(μ-dppm)(CO)₈(dppn) (5), obtained from Ru₃(μ-dppm)(CO)₁₀ and dppn in refluxing thf.     

Dinuclear copper(I) complexes containing diimine and phosphine ligands: Synthesis, copper-copper separation and photophysical properties

Dinuclear copper(I) complexes with bridging bis(dicyclohexylphosphino)methane (dcpm) or bis(diphenylphosphino)methane (dppm) and 2,2′-bipyridine or 2-[N-(2-pyridyl)methyl]amino-5,7-dimethyl-1,8-naphthyridine (L), [Cu₂(bpy)₂(dppm)₂](BF₄)₂ (1), [Cu₂(bpy)₂(dcpm)](BF₄)₂ (2), [Cu₂(L)(dppm)](BF₄)₂ (3) and [Cu₂(L)(dcpm)](BF₄)₂ (4) were prepared, and their structures were determined by X-ray crystal analysis. Two-, three-, and four-coordinate copper(I) centers are found in these complexes. Compounds 3 and 4 show close Cu^I?Cu^I separations of 2.664(3) and 2.674(1) Å, respectively, whereas an intramolecular copper-copper distance of 3.038 Å is found in 2 having only dcpm as an additional bridge. Powdered samples of 1, 3, and 4 display intense and long-lived phosphorescence with λ_max at 533, 575, and 585 nm at room temperature, respectively. In the solid state, 2 exhibits only a weak emission at 555 nm. The time-resolved absorption and emission spectra of these complexes were investigated. The difference in the emission properties among complexes 1-4 suggests that both Cu^I?Cu^I distances and coordination environment of the copper(I) centers affect the excited-state properties.     

Syntheses and molecular structures of 6-halogeno-pyridin-2-olate complexes with the diruthenium(2+) core

The complexes [Ru₂(CO)₅(μ-FpyO)₂]₂ (1), [Ru₂(CO)₄(μ-ClpyO)₂]₂ (2), and [Ru₂(CO)₄(μ-BrpyO)₂]₂ (3) were prepared from Ru₃(CO)₁₂ and 6-fluoro-2-hydroxypyridine (FpyOH), 6-chloro-2-hydroxypyridine (ClpyOH) and 6-bromo-2-hydroxypyridine (BrpyOH), respectively, in hot toluene. Compounds 1-3 are coordination dimers with a cyclo-RuORuO motif. By carrying out the reaction in hot methanol, the dinuclear complexes [Ru₂(CO)₄(μ-ClpyO)₂(CH₃OH)] (4) and [Ru₂(CO)₄(μ-BrpyO)₂(CH₃OH)] (5), respectively, were obtained. Treatment of 2 and 3 with triphenylphosphane provided the complexes [Ru₂(CO)₄(μ-ClpyO)₂(PPh₃)] (6) and [Ru₂(CO)₄(μ-BrpyO)₂(PPh₃)] (7), respectively. The solid-state structures of complexes 1, 2, 4, 6, and 7 were determined by single crystal X-ray diffraction. In all cases, a head-head coordination of the two 6-halopyridinolate ligands at the core was found. In all chlorine- or bromine-containing complexes, the axial coordination site at the ruthenium atom neighbored by two Cl or Br atoms remains unoccupied due to steric shielding by the halogen atom. In the fluoropyridinolate complex 1, the same coordination site is occupied by a carbonyl ligand.     

A zigzag chain coordination polymer consisting of silver(I) ion having square planar geometry

Silver(I) complexes of hexakis(tolylsulfanyl)benzene (htsb), [Ag(htsb)](PF₆) (1), have been prepared and their molecular structures were determined by X-ray crystallography. In 1, the silver ion prefers a square planar coordination geometry comprized of four S atoms from two different htsb molecules and producing a zigzag chain structure of AgS in the silver coordination polymer. Based on the thermo-gravimetry analysis results, two tolylsulfanyl groups were easily eliminated at approximately 211 °C. However, [Ag(htsb)(2-butanone)] (PF₆) (2), which were obtained by the reactions in different solvents, showed a different colors and thermal degradation behaviors.