Effects of the ancillary ligands of polypyridyl ruthenium(II) complexes on the DNA-binding and photocleavage behaviors

The new polypyridyl ligand MIP {MIP = 2-(2,3-methylenedioxyphenyl)imidazo[4,5-f]1,10-phenanthroline} and its ruthenium(II) complexes [Ru(phen)₂(MIP)]²⁺ (1) (phen = 1,10-phenanthroline) and [Ru(dmp)₂(MIP)]²⁺ (2) (dmp = 2,9-dimethyl-1,10-phenanthroline) were synthesized and characterized by elemental analysis, MS and ¹H NMR spectroscopy. The DNA-binding properties of the two complexes to calf-thymus DNA (CT-DNA) were investigated by different spectrophotometric methods and viscosity measurements, as well as equilibrium dialysis and circular dichroism spectroscopy. The results suggest that complex 1 binds to CT-DNA through intercalation, and complex 2 binds to CT-DNA via a partial intercalative mode. This difference in binding mode probably is caused by the different ancillary ligands. Also, when irradiated at 400 nm, complex 1 was found to be a more-effective DNA-cleaving agent than complex 2.     

Neutral pyridylmethylamide ligands and their mononuclear copper(II) complexes

Mononuclear copper(II) complexes of a family of pyridylmethylamide ligands HL, HL^Me, HL^Ph, HL^Me3 and HL^Ph3, [HL = N-(2-pyridylmethyl)acetamide; HL^Me = N-(2-pyridylmethyl)propionamide; HL^Ph = 2-phenyl-N-(2-pyridylmethyl)acetamide; HL^Me3 = 2,2-dimethyl-N-(2-pyridylmethyl)propionamide; HL^Ph3 = 2,2,2-triphenyl-N-(2-pyridylmethyl)acetamide], were synthesized and characterized. The reaction of copper(II) salts with the pyridylmethylamide ligands yields complexes [Cu(HL)₂(OTf)₂] (1), [Cu(HL^Me)₂](ClO₄)₂ (2), [Cu(HL)₂Cl]₂[CuCl₄] (3), [Cu(HL^Me3)₂(THF)](OTf)₂ (4), [Cu(HL^Me3)₂(H₂O)](ClO₄)₂ (5a and 5b), [Cu(HL^Ph3)₂(H₂O)](ClO₄)₂ (6), [Cu(HL)(2,2′-bipy)(H₂O)](ClO₄)₂ (7), and [Cu(HL^Ph)(2,2′-bipy)(H₂O)](ClO₄)₂ (8). All complexes were fully characterized, and the X-ray structures vary from four-coordinate square-planar, to five-coordinate square-pyramidal or trigonal-bipyramidal. The neutral ligands coordinate via the pyridyl N atom and carbonyl O atom in a bidentate fashion. The spectroscopic properties are typical of mononuclear copper(II) species with similar ligand sets, and are consistent their X-ray structures.     

Three copper(II) complexes constructed from a new 1,3,5-triazine derivative ligand

Three new complexes {[Cu(dpdapt)(Hhbd)] · 6H₂O}_n (1) (dpdapt = N,N′-di(2-pyridyl)-2,4-diamino-6-phenyl-1,3,5-triazine, Hhbd = 2-hydroxybutanedioicate dianion), [Cu(dpdapt)(SO₄)] · 2H₂O (2) and [Cu(dpdapt)(oxa)] · H₂O (3) (oxa = oxalate dianion) have been synthesized and structurally characterized. The non-covalent interactions of π–π stacking and hydrogen bonding extend complexes 1–3 into supramolecular architectures, where 1 self-assembles into a 1D polymeric chain by dicarboxylate bridges and exhibits a 3D framework with 1D open channels, while complexes 2 and 3 display 2D wavelike networks. Interestingly, in 1, the host framework encapsulates hexameric water clusters that are connected into 1D arrays by supramolecular association along the 1D open channels. The UV/vis, IR spectra, fluorescence and TG analysis for complexes 1, 2 and 3 are also discussed.     

Ring-opening metathesis polymerization of norbornene and norbornadiene by tungsten(II) and molybdenum(II) complexes

The reaction of norbornene (NBE) and norbornadiene (NBD) in the presence of seven-coordinate tungsten(II) and molybdenum(II) complexes of the [(CO)₄M(μ-Cl)₃M(SnCl₃)(CO)₃] and [MCl(M′Cl₃)(CO)₃(NCMe)₂] (M=W, Mo; M′=Sn, Ge) types leads to ring-opening metathesis polymerization (ROMP) and to the formation of high molecular weight polymers. The geometric structure of these polymers was determined by means of ¹H- and ¹³C-NMR spectroscopy. The monitoring of the reaction between cyclic olefins and the metal complex by means of ¹H-NMR spectroscopy allowed us to observe the coordination of NBD to metal atoms in the initiation step of the polymerization process. Compounds of the [MCl(SnCl₃)(CO)₃(η⁴-NBD)] type prepared directly from [(CO)₄M(μ-Cl)₃M(SnCl₃)(CO)₃] or [MCl(M′Cl₃)(CO)₃(NCMe)₂] (M=W, Mo) in the presence of an excess of NBD initiate the ROMP reaction immediately. The detection of the first-formed products in the reaction between the metal complex and cyclic olefins provides valuable information concerning the nature of the initiating species.     

Synthesis, characterization and magnetic properties of novel μ-isophthalato oxovanadium(IV) binuclear complexes

Four novel oxovanadium(IV) binuclear complexes have been synthesized, namely [(VO)₂(IPHTA) (L)₂SO₄ (L denotes 2,2′-bipyridine (bpy); 1,10-phenanthroline (phen); 4,4′-dimethyl-2,2′-bipyridine (Me₂bpy) and 5-nitro-1,10-phenanthroline (NO₂-phen)), where IPHTA is the isophthalate dianon. Based on elemental analyses, molar conductivity measurements, IR and electronic spectra studies, it is proposed that these complexes have IPHTA-bridged structures and consist of two vanadium(IV) atoms in a square-pyramidal environment. The complexes [(VO)₂(IPHTA)(Me₂bpy)₂]SO₄ (1) and [(VO)₂(IPHTA)(bpy)₂]SO₄ (2) were characterized by variable temperature magnetic susceptibility (4–300 K) and the data could be well fitted by the least-squares method to a susceptibility equation derived from the spin Hamiltonian operator, . The exchange integral, J, was found to be −26.8 cm⁻¹ for (1) and −31.0 cm⁻¹ for (2). These results are commensurate with antifferomagnetic interactions between two oxovanadium(IV) ions within each molecule. The influence of different terminal ligands on magnetic interactions between the metals of this kind of complexes is also discussed.     

Mononuclear Pt(II) and Pd(II) 1,4-dithiolato complexes. Crystal structures of [Pt((−) DIOS) (PPh3)2] and [Pd(S(CH2) 4S)(Ph2P(CH2) 3PPh2)]. Application in styrene hydroformylation

Addition of 1,4-dithiols to dichloromethane solutions of [PtCl₂(P-P)] (P-P = (PPh₃)₂, Ph₂P(CH₂)₃PPh₂, Phd₂P(CH₂)₄PPh₂; 1,4-dithiols = HS(CH₂)₄SH, (−)DIOSH₂ (2,3-O-isopropylidene-1,4-dithiol-l-threitol), BINASH₂ (1,1′-dinaphthalene-2,2′-dithiol)) in the presence of NEt₃ yielded the mononuclear complexes [Pt(1,4-dithiolato)(P-P)]. Related palladium(II) complexes [Pd(dithiolato)(P-P)] (P-P=Ph₂P(CH₂)₃PPh₂, Ph₂P(CH₂)₄PPh₂; dithiolato = ⁻S(CH₂)₄S⁻, (−)-DIOS) were prepared by the same method. The structure of [Pt((−)DIOS)(PPh₃)₂] and [Pd(S(CH₂)₄S)(Ph₂P(CH₂)₃PPh₂)] complexes was determined by X-ray diffraction methods. Pt—dithiolato—SnC1₂ systems are active in the hydroformylation of styrene. At 100 atm and 125°C [Pt(dithiolate)(P-P)]/SnCl₂ (Pt:Sn = 20) systems provided aldehyde conversion up to 80%.     

Photochemical reactions of alkynyl iron (II) complexes with carbon disulfide. Insertion of CS2 into an iron-C(sp) bond

The novel alkynyldithiocarboxylate complexes [Fe(η⁵-C₅H₅)(S₂CCCR) (dppm-P)] (3a,b) and [Fe(η₅-C₅H₅)(S₂CCCR)(PPh₃)] (4a,b) were obtained through the insertion of CS₂ into the iron-akynyl bond in the complexes [Fe(η₅-C₅H₅)(CCR)(L)(L′] L, L′ = dppm R = Ph (1a), ^tBu(1b); L = (CO), L′ = (PPh₃) R = Ph (2a), ^tBu (2b). Variable-temperature ³¹P{¹H} NMR studies indicate the presence of two different isomers, [Fe(η⁵-C₅H₅)(η³-S,C,S′---S₂CCCR)(L)(L′)] and [Fe(η⁵-C₅H₅(η²-S,S′-S₂CCCR)(L)(L′)], which rapidly interconvert at room temperature. The synthesis of the precursor complex [Fe(η⁵-C₅H₅)(CC^tBu)(CO)(PPh₃)] is also described.     

N,N′-bis(substituted-phenyl)oxamides and their dinuclear pentacoordinate nickel(II) complexes

The preparation, spectroscopic characterization and magnetic study of N,N′-bis(substituted-phenyl)oxamidate-bridged nickel(II) dinuclear complexes of formula {[Ni(N₃-mc)]₂(μ-CONC₆H₄-X)}(PF₆)₂ (N₃-mc = 2,4,4-trimethyl-1,5,9-triazacyclo-dodec-1-ene (Me₃-N₃-mc) or 2,4,4,9-tetramethyl-1,5,9-triazacyclododec-1-ene (Me₄-N₃-mc), X = 2-Cl, 4-Cl, 2-OCH₃, 4-OCH₃) are reported. These paramagnetic nickel(II) complexes have been characterized by both one- and two-dimensional (COSY) ¹H NMR techniques. The COSY spectrum of 5 has allowed to achieve the assignment of the phenyl protons of the N,N′-diphenyloxamidate. The crystal structures of [Ni(Me₃-N₃-mc)(μ-CONC₆H₄-4-Cl)]₂(PF₆)₂ (6), [Ni(Me₃-N₃-mc)(μ-CONC₆H₄-4-OMe)]₂(PF₆)₂ (8) and [Ni(Me₄-N₃-mc)(μ-CONC₆H₄-2-Cl)]₂(PF₆)₂ (9) have been determined and their magnetic properties have been studied. The value of magnetic coupling between the two nickel(II) ions across the oxamidate bridge [J = − 37.6 (6), −39.9 (8) and −39.7 cm⁻¹ (9)] is sensitive to the distortion of the coordination sphere of the metal ions and the topology of the molecular bridge.     

Synthesis, reaction and structure of a series of chromium(III) complexes containing oxalate ligand

A series of chromium(III) complexes [Cr(bipy)(HC₂O₄)₂]Cl·3H₂O (1), [Cr(phen)(HC₂O₄)₂]Cl·3H₂O (2), [Cr(phen)₂(C₂O₄)]ClO₄ (3), [Cr₂(bipy)₄(C₂O₄)](SO₄)·(bipy)_0.5·H₂O (4) and [Mn(phen)₂(H₂O)₂]₂[Cr(phen)(C₂O₄)₂]₃ClO₄·14H₂O (5) were synthesized (bipy=4,4′-bipyridine, phen=1,10-phenanthroline), while the crystal structures of 1 and 3–5 have been determined by X-ray analysis. 1 and 3 are mononuclear complexes, 4 contains binuclear chromium(III) ions and 5 is a 3D supromolecule formed by complicated hydrogen bonding. 1–3 are potential molecular bricks of chromium(III) building blocks for synthesis heterometallic complexes. When we use these molecular bricks as ligands to react with other metal salts, unexpected complexes 4 and 5 are isolated in water solution. The synthesis conditions and reaction results are also discussed.     

Theoretical and experimental investigation of novel iron(II)-based spin crossover compounds

Two novel spin crossover (SCO) compounds, namely [Fe(INMe)(pyN₄)]Br₂, and [Fe(IMMe)(pyN₄)](OTf)₂, where pyN₄ = 2,6-Bis(1′,3′-diamino-2′methyl-prop-2′yl)pyridine, INMe = isonicotinic acid methyl ester, IMMe = N-methyl-imidazole, and OTf = triflate, are characterized here both from experimental and theoretical viewpoints. In particular, we apply various density functionals and basis sets to obtain optimized geometries for low- (LS) and high-spin (HS) states, vibrational spectra, LS–HS splittings, and temperature-dependent UV/vis spectra. While geometries and spectra are in good agreement with experimental data, the well-known spin pairing problem makes it difficult to compute accurate LS–HS splitting energies and enthalpies. Based on TD–DFT calculations, the capacity of the compounds for use as reversibly photo-switchable molecules is discussed.     

Synthesis, spectra and crystal structures of two Ru complexes with polypyridyl ligands: cis-[Ru(bpy)2(4,4′-bpy)Cl](PF6)·H2O and cis-[Ru(phen)2(CH3CN)2](PF6)2

Two mononuclear Ru^II complexes of polypyridyl ligands, cis-[Ru(bpy)₂(4,4′-bpy)Cl](PF₆)·H₂O (1) and cis-[Ru(phen)₂(CH₃CN)₂](PF₆)₂ (2) (bpy=2,2′-bipyridyl, 4,4′-bpy=4,4′-bipyridyl, and PHEN=1,10-phenanthroline), have been synthesized and characterized by elemental analyses, IR and UV–vis spectra. The crystal structures of both complexes have been determined by X-ray diffraction, indicating that each Ru^II center is hexa-coordinated (RuN₅Cl for 1 and RuN₆ for 2) and takes a distorted octahedral geometry. The favored feature of both complexes is that they are quite useful complex precursors for further constructing new functional architectures.     

Synthesis and structural characterisation of cobalt(II) and iron(II) chloride complexes containing bis(2-pyridylmethyl)amine and tris(2-pyridylmethyl)amine ligands

Treatment of (2-C₅H₄N)CH_{2 3}N (TPA) with one equivalent of MCl₂ in n-BuOH at elevated temperatures affords the six-coordinate complexes [(TPA)MCl₂] (M = Co (1), Fe (2)) and, in the case of CoCl₂, the five-coordinate chloride salt [(TPA)CoCl]Cl (3). Conversely, addition of an excess of CoCl₂ in the latter reaction leads to [(TPA)CoCl]₂[CoCl₄] (4) as the only isolable product. Interaction of one equivalent of (2-C₅H₄N)CH_{2 2}NH (DPA) and MCl₂ under similar reaction conditions to that described above affords the dimeric species [(fac-DPA)MCl(μ-Cl)]₂ (M = Co (5), Fe (6)), while the bis(ligand) halide salts [(fac-DPA)₂M]Cl₂ (M = Co (7), Fe (8)) are accessible on addition of two equivalents of DPA. In the presence of air, 6 undergoes oxidation to give [ (fac-DPA)FeCl_{2 2}(μ-O)] (9). Single-crystal X-ray diffraction studies are reported for 1, 2 · MeCN, 3, , 7 · 3MeCN, 8 · 3MeCN and 9.     

Synthesis and spectroscopic, magnetic and EPR studies of di-μ-hydroxo-bis[(NN)(N-phenyl-2-pyridinamine)copper(II)]hexaflourophosphate, with NN=2,2′-bipyridine or 1,10-phenanthroline.: X-ray crystal structure of the 2,2′-bipyridine complex

Binuclear complexes [{Cu(NN)(PhNHpy)}₂(μ-OH)₂](PF₆)₂, where NN=2,2′-bipyridine (bipy) or 1,10-phenanthroline (phen), have been synthesized and characterized by chemical analysis, conductance measurements and IR and electronic spectroscopy. The X-ray crystal structure of [{Cu(bipy)(PhNHpy)}₂(μ-OH)₂](PF₆)₂ shows a distorted square-planar pyramidal coordination for Cu(II), defined by two nitrogen atoms of bipy, two bridging oxygen atoms and the pyridinic nitrogen atom of the ligand. Magnetic susceptibility measurements (in the 4.8–290 K range) reveal coupling which is antiferromagnetic for the bipy complex (2J=−24.2 cm⁻¹) and slightly ferromagnetic for the phen complex (2J=3.3 cm⁻¹). The EPR spectra show the expected triplet signals.     

Solvothermal syntheses and crystal structures of two metal coordination polymers with double-chain structures

Two polymeric complexes, [Cu₂(btec)(phen)₂]_n·(H₂O)_n (1) and [Cd₄(btec)₂(phen)₄(H₂O)₄]_n (2) (H₄btec=1,2,4,5-benzenetetracarboxylic acid; PHEN=1,10-phenanthroline), were synthesized by solvothermal reactions at 140 °C. Both complex 1 and 2 possess infinite double-chain structures, in which each Cu(II) center has a tetrahedral configuration and the Cd(II) centers adopt triangular prismatic and square-based pyramidal configurations simultaneously. The inter-chain face to face π–π interactions among the aromatic rings of phen and the hydrogen bond interactions between aqua molecules and carboxyl O atoms result in 3-D networks in the two complexes. The ESR spectra study of complex 1 shows that there is negligibly small long-range super-exchange interactions between the Cu(II) atoms via benzenecarboxylate bridging.     

Structures of 3,3′-dicarbometoxy-2,2′-bipyridine complexes with silver(I) and copper(II) cations

The structures of 3,3′-dicarbometoxy-2,2′-bipyridine (dcmbpy) complexes with copper(II) and silver(I) cations have been determined using single crystal X-ray-diffraction. The crystals of Cu(dcmbpy)Cl₂ are monoclinic, C2/c, a = 16.966(3), b = 18.373(3), c = 13.154(2) Å, β = 126.543(3)°. The crystals of Ag(dcmbpy)NO₃ · H₂O are also monoclinic, C2/c, a = 16.7547(13), b = 11.0922(9), c = 18.7789(18) Å, β = 100.228(7)°. The results have been compared with the literature data on the complexes of dcmbpy and its precursors: 2,2′-bipyridine (bpy) and 3,3′-dicarboxy-2,2′-bipyridine (dcbpy). Two types of complexes of 3,3′-carboxy derivatives of bpy are distinguished: (1) with metal atom bonded to two N atoms of the same molecule and (2) with metal atom bonded to two N atoms of two different molecules. The Cu(dcmbpy)Cl₂ complex belongs to the first type, whereas Ag(dcmbpy)NO₃ · H₂O belongs to the second type.     

Three new polynuclear tetracarboxylato-bridged copper(II) complexes: Syntheses, X-ray structure and magnetic properties

The synthesis, crystal structure and magnetic measurements of three new polynuclear tetracarboxylato-bridged copper(II) complexes, i.e. {[Cu₄(phen)₂(μ-O₂CC₂H₅)₈] · (H₂O)}_n (1), [Cu₂(μ-O₂CC₆H₄OH)₄(C₇H₇NO)₂] · 6H₂O (2) and [Cu₂(μ-O₂CCH₃)₄(C₇H₇NO)₂] (3) (phen = 1,10-phenanthroline, O₂CC₆H₄OH = 3-hydroxy benzoate, C₇H₇NO = 4-acetylpyridine) are reported. All compounds consist of dinuclear units, in which two Cu(II) ions are bridged by four syn,syn-η¹:η¹:μ carboxylates, showing a paddle-wheel cage type with a square-pyramidal geometry, arranged in different ways. The structure of compound 1 consists of an one-dimensional structure generated by an alternating classical dinuclear paddle-wheel unit and an unusual dinuclear Cu₂(μ-OCOC₂H₅)₂(μ-O₂CC₂H₅)₂(phen)₂unit, which are connected to each other via a syn,anti-triatomic propionato bridge in an axial-equatorial configuration. The adjacent chains are connected to generate a 2D structure through the face-to-face π–π interaction between phen rings. Structures of compounds 2 and 3 both consist of a symmetric dinuclear Cu(II) carboxylate paddle-wheel core and pyridyl nitrogen atoms of 4-acetylpyridine ligand at the apical position, and just differ in the substituents of the equatorial ligands.

The magnetic properties have been measured and correlated with the molecular structures. It is found that in the two classical paddle-wheel compounds the Cu(II) ions are strongly antiferromagnetically coupled with J = −278.5 and −287.0 cm⁻¹ for complexes 2 and 3, respectively. In compound 1 the magnetic susceptibility could be fitted with two different, independent Cu(II) units, one strongly coupled and one weakly coupled; the paddle-wheel dinuclear unit has the strongest antiferromagetic coupling with a value for J of −299.5 cm⁻¹, whereas the Cu(II) ions in the propionato-bridged dinuclear unit of 1 display a very weak antiferromagnetic coupling with a value for J = −0.75 cm⁻¹, due to the orthogonality of the magnetic orbitals. Also the exchange within the chain is therefore very weak. The magneto-structural correlations for complexes 1, 2, and 3 are discussed on the basis of the structural parameters and magnetic data for the complexes.     

Direct electrosynthesis of halo and mixed-halo complexes of palladium(II and IV) by the dissolution of a sacrificial palladium anode in aqueous medium

A rapid single-step method for the electrosynthesis of chloro and bromo complexes of palladium(II and IV), viz. M₂[PdX₄] and M₂[PdX₆], by the dissolution of a palladium anode in chloride or bromide containing media is described. Electrolysis of dilute HX solution in the presence of pyridine, 2,2′-bipyridyl or 1,10-phenanthroline gives rise to non-electrolytes, e.g. trans-[PdX₂(py)₂], [PdX₂(bipy)] and [PdX₂(phen)]. Anodic oxidation of palladium in HX medium in the presence of acetonitrile and benzonitrile also gives the non-electrolytes trans-[PdX₂(CH₃CH₂NH₂)₂] and trans-[PdX₂(C₆H₅CH₂NH₂)₂], respectively.     

Synthesis and characterization of uranium(III) compounds supported by the hydrotris(3,5-dimethyl-pyrazolyl)borate ligand: Crystal structures of [U(Tp)2(X)] complexes (X = OC6H2-2,4,6-Me3, dmpz, Cl)

Reaction of [U(Tp^Me2)₂(NR₂)] (R = Ph, SiMe₃) with protic substrates such as 2,4,6-trimethylphenol (HOC₆H₂-2,4,6-Me₃), 3,5-dimethylpyrazole (Hdmpz), 2-mercaptopyridine (HSC₅H₄N) and phenylacetylene (HCCPh) afforded the corresponding [U(Tp^Me2)₂(OAr)] (Ar = C₆H₂-2,4,6-Me₃) (1), [U(Tp^Me2)₂(dmpz)] (2), [U(Tp^Me2)₂(η²-SC₅H₄N)] (3), and [U(Tp^Me2)₂(CCPh)] (4) compounds. Reaction of [U(Tp^Me2)₂(NR₂)] with Me₃SnCl or Me₃SiBr gave [U(Tp^Me2)₂Cl] (5) and [U(Tp^Me2)₂Br] (6), respectively, in high yield. The amido precursors failed to react with cyclopentadiene, but metathesis of [U(Tp^Me2)₂I] with NaCp yielded [U(κ³-Tp^Me2)(κ²-Tp^Me2)(η⁵-Cp)] (7). Thermolysis of 7 resulted in oxidation of the metal centre and redistribution of the ligands, giving [UCp₃(dmpz)] (8), pyrazabole (9) and [U(Tp^Me2)(dmpz)₃] (10). The complexes have been fully characterized by spectroscopic methods and the structures of 1, 2, and 5 were confirmed by X-ray crystallographic studies. In the solid state the complexes exhibit distorted pentagonal bipyramidal geometries.     

Synthesis of mer-[RuCl3(DMSO)(bpy)], reactivity and electrochemistry of mer-[RuCl3(DMSO)(bpy)] and mer-[RuCl3(TMSO)(bpy)] complexes

[H(DMSO)₂][trans-RuCl₄(DMSO)₂] (1) reacts with 2,2′-bipyridine in ethanol at room temperature resulting in the formation of a major compound, mer-[RuCl₃(DMSO)(bpy)] (bpy = 2,2′-bipyridine) 3 and a known minor compound, cis-[RuCl₂(DMSO)₄] (4). The compounds 3 and 4 are formed via an anticipated intermediate mer-[RuCl₃(DMSO)₃] (2). The reaction of 3 and mer-[RuCl₃(TMSO)(bpy)] (5) with small molecules like imidazole, carbon monoxide and KSCN yield, mer-[RuCl₃(bpy)(im)] · 2DMSO (im = imidazole) (6) and cis-[RuCl₂(TMSO)(CO)(bpy)] (7), cis-[RuCl₂(DMSO)(CO)(bpy)] (8) and K[RuCl₃(bpy)(SCN)] (9), respectively. The formations of 3, 6 and 7 have been authenticated by single crystal structure determinations. Compound 6 is formed by the substitution of DMSO or TMSO from 3 and 5, respectively, whereas 7 and 8 are formed by unprecedented one-electron reductions of 5 and 3. The reactions of 3 and 5 with KSCN resulted in the same compound, K[RuCl₃(NCS)(bpy)] (9). DFT calculations were performed to distinguish whether the thiocyanate ligand is bound to ruthenium through S or N. In the ruthenium bipyridine systems, the HOMO contains ruthenium d-orbitals and the LUMO is typically π^*-orbitals of the bipyridine ring. Complexes 3, 6 and 7 are redox active in acetone and DMSO solvent showing prominent a reduction peak and corresponding oxidation peak.     

Synthesis, characterization and photophysics of bimetallic manganese(I) and ruthenium(II) complexes

A series of new manganese(I) and ruthenium(II) monometallic and bimetallic complexes made of 2,2′-bipyridine and 1,10-phenanthroline ligands, [Mn(CO)₃(NN)(4,4′-bpy)]⁺, [{(CO)₃(NN)Mn}₂(4,4′-bpy)]²⁺ and [(CO)₃(NN)Mn(4,4′-bpy)Ru(NN)₂Cl]²⁺ (NN = 2,2′-bipyridine, 1,10-phenanthroline; 4,4′-bpy = 4,4′-bipyridine) are synthesized and characterized, in addition to already known ruthenium(II) complexes [Ru(NN)₂Cl(4,4′-bpy)]⁺ and [Cl(NN)₂Ru(4,4′-bpy)Ru(NN)₂Cl]²⁺. The electrochemical properties show that there is a weak interaction between two metal centers in Mn–Ru heterobimetallic complexes. The photophysical behavior of all the complexes is studied. The Mn(I) monometallic and homobimetallic complexes have no detectable emission. In Mn–Ru heterobimetallic complexes, the attachment of Mn(I) with Ru(II) provides interesting photophysical properties.