Synthesis and structural characterization of dinuclear iridium hydrido complex with 3,6-bis(2-pyridyl)tetrazine, [Ir2(H)4(PPh3)4(bptz)](PF6)2 · 4CH2Cl2

Reaction of the precursor Ir complex [Ir(H)₂(PPh₃)₂(Me₂CO)₂]PF₆ with 3,6-bis(2-pyridyl)tetrazine (bptz) in CH₂Cl₂ gave a novel dinuclear Ir hydrido complex [Ir₂(H)₄(PPh₃)₄(bptz)](PF₆)₂ · 4CH₂Cl₂. Crystallographic study described an interesting coordination environment having a π-π interaction and ¹H NMR study showed unique upfield shifts of pyridyl rings that are likely induced by the ring current effect of neighboring PPh₃ ligands.     

Sn-S and Ru-Ru bonds cleavage reactions between [Ph3SnS(CH2)3SSnPh3] and Ru3(CO)12: X-ray crystal structures of [Ph3SnS(CH2)3SSnPh3] and trans-[Ru(CO)4(SnPh3)2]

The organotin complex [Ph₃SnS(CH₂)₃SSnPh₃] (1) was synthesized by PdCl₂ catalyzed reaction between Ph₃SnCl and disodium-1,3-propanedithiolate which in turn was prepared from 1,2-propanedithiol and sodium in refluxing THF. Reaction of 1 with Ru₃(CO)₁₂ in refluxing THF affords the mononuclear complex trans-[Ru(CO)₄(SnPh₃)₂] (2) and the dinuclear complex [Ru₂(CO)₆(μ-κ²-SCH₂CH₂CH₂S)] (3) in 20 and 11% yields, respectively, formed by cleavage of Sn-S bond of the ligand and Ru-Ru bonds of the cluster. Treatment of pymSSnPPh₃ (pymS = pyrimidine-2-thiolate) with Ru₃(CO)₁₂ at 55-60 °C also gives 2 in 38% yield. Both 1 and 2 have been characterized by a combination of spectroscopic data and single crystal X-ray diffraction analysis.     

Syntheses, characterizations and crystal structures of two lead(II) diphosphonates: Pb2[NH(CH2PO3)2] · 2H2O and Pb3[HO2C(CH2)3NH(CH2PO3)2]2 · 2H2O

Hydrothermal reactions of lead(II) acetate and HO₂C(CH₂)₃N(CH₂PO₃H₂)₂ at 170 and 140 °C, respectively, resulted in two different lead diphosphonates, namely, Pb₂[NH(CH₂PO₃)₂] · 2H₂O (1), in which the butyric acid moiety of the HO₂C(CH₂)₃N(CH₂PO₃H₂)₂ has been cleaved and a novel layered compound, Pb₃[HO₂C(CH₂)₃NH(CH₂PO₃)₂]₂ · 2H₂O (2). Their crystal structures have been determined by single crystal X-ray diffraction. In compound 1, the interconnection of the lead(II) ions by bridging amino-diphosphonate ligands leads to the formation of a 3D network. Compound 2 features an unusual triple-layer structure with the non-coordinated butyric acid moieties as pendant groups between the layers.     

Syntheses and structures of the heterometallic clusters [(Ph3PAu)3Re(CO)4], [(Ph3PAu)4Re(CO)4], [(Ph3PAu)6AuRe2(CO)8], and [(Ph3PAu)6Re(CO)3]

The reaction of [HRe₃(CO)₁₂]²⁻ with an excess of Ph₃PAuCl in CH₂Cl₂ yields [(Ph₃PAu)₄Re(CO)₄]⁺ as the main product, which crystallizes as [(Ph₃PAu)₄Re(CO)₄]PF₆ · CH₂Cl₂ (1 · CH₂Cl₂) after the addition of KPF₆.The crystal structure determination reveals a trigonal bipyramidal Au₄Re cluster with the Re atom in equatorial position.If [(Ph₃PAu)₄Re(CO)₄]⁺ is reacted with PPh₄Cl, a cation [Ph₃PAu]⁺ is eliminated as Ph₃PAuCl, and the neutral cluster [(Ph₃PAu)₃Re(CO)₄] (2) is formed.It combines with excess [(Ph₃PAu)₄Re(CO)₄]⁺ to afford the cluster cation, [(Ph₃PAu)₆AuRe₂(CO)₈]⁺. It crystallizes from CH₂Cl₂ as[(Ph₃PAu)₆AuRe₂(CO)₈]PF₆ · 4CH₂Cl₂ (3 · 4CH₂Cl₂). In [(Ph₃PAu)₃Re(CO)₄] the metal atoms are arranged in form of a lozenge while in [(Ph₃PAu)₆AuRe₂(CO)₈]⁺ two Au₄Re trigonal bipyramids are connected by a common axial Au atom.The treatment of [(Ph₃PAu)₄Re(CO)₄]⁺ with KOH and Ph₃PAuCl in methanol yields the cluster cation [(Ph₃PAu)₆Re(CO)₃]⁺, which crystallizes with from CH₂Cl₂ as [(Ph₃PAu)₆Re(CO)₃]PF₆ · CH₂Cl₂ (4 · CH₂Cl₂). The metal atoms in this cluster form a pentagonal bipyramid with the Re atom in the axial position.     

Synthesis and structural characterization of trans-[Mo2(H2DMepyF)2(CH3CN)4](BF4)6 (HDMepyF=N,N-di(6-methyl-2-pyridyl)formamidine)

Reaction of Mo₂(O₂CCH₃)₂(DMepyF)₂ (HDMepyF=N,N^′-di(6-methyl-2-pyridyl)formamidine) with HBF₄ in CH₂Cl₂/CH₃CN afforded the complex trans-[Mo₂(H₂DMepyF)₂(CH₃CN)₄](BF₄)₆ (1), which crystallized in two forms, trans-[Mo₂(H₂DMepyF)₂(CH₃CN)₄](ax-CH₃CN)₂(BF ₄)₆ · 2CH₃CN (1a), and trans- [Mo₂(H₂DMepyF)₂(CH₃CN)₄](ax-BF₄) ₂(BF₄)₄ · 2CH₃CN (1b). The molecular structures of complexes (1) consist of two quadruply bonded molybdenum atoms, which are spanned by two trans-bridging formamidinate ligands and coordinated by four trans-CH₃CN. Each H₂DMepyF⁺ ligand adopts an s-cis,s-cis- conformation. The difference between 1a and 1b is that complex 1a contains two CH₃CN molecules as axial ligands, while 1b contains two BF₄⁻ anions as axial ligands. Complex 1 is the first dimolybdenum complex containing a pair of trans bridging ligands and two pairs of trans-CH₃CN ligands.     

‘Synthetic prospecting’ using an electrospray ionisation mass spectrometry directed survey of the alkylation and arylation chemistry of [Pt2(μ-S)2(PPh3)4]

Electrospray ionisation mass spectrometry (ESI-MS) has been used as an analytical tool in a wide-ranging scoping study of the alkylation and arylation reactions of [Pt₂(μ-S)₂(PPh₃)₄]. From these experiments, the factors that influence the formation of different product species - formed by mono- or di-alkylation - are determined. If the alkylating agent is an alkyl chloride or sulfate, monoalkylation followed by dialkylation of the two sulfido groups occurs, dependent on the alkylating power of the reagent used. For example, n-butyl chloride gives solely [Pt₂(μ-S)(μ-SBu)(PPh₃)₄]⁺ while dimethyl sulfate gives [Pt₂(μ-SMe)₂(PPh₃)₄]²⁺. This species, previously unisolated is stable in the absence of good nucleophiles, but the addition of potassium iodide results in rapid conversion to [Pt₂(μ-SMe)₂(PPh₃)₃I]⁺. This iodo complex is also observed from the reaction of [Pt₂(μ-S)₂(PPh₃)₄] with excess MeI, after the initial formation of mono- and di-methylated species. In these reactions, the iodide presumably displaces a phosphine ligand, which is then quaternised by excess alkylating agent. Changing the alkylating agent to a longer chain alkyl iodide or methyl bromide decreases the rate of alkylation of the sulfide in the initially formed [Pt₂(μ-S)(μ-SR)(PPh₃)₄]⁺. Mixed-thiolate species of the type [Pt₂(μ-SMe)(μ-SR)(PPh₃)₄]²⁺ are easily generated by reaction of [Pt₂(μ-S)(μ-SR)(PPh₃)₄]⁺ with excess Me₂SO₄ and is also dependent on the avoidance of nucleophiles. Reactions towards α,ω-dialkylating agents are surveyed; the chain length is found to have a dramatic effect on the rate of the second intramolecular cyclisation process, illustrated by a competitive reactivity study involving a mixture of Br(CH₂)₄Br and Br(CH₂)₅Br; on completion of the reaction the former gives [Pt₂{μ-S(CH₂)₄S}(PPh₃)₄]²⁺ while the latter predominantly gives monoalkylated[Pt₂(μ-S){μ-S(CH₂)₅Br}(PPh₃)₄]⁺. The reactivity of o- and p-dihaloxylenes has been explored, with the reaction with p-BrCH₂C₆H₄CH₂Br giving the bridged species [(PPh₃)₄Pt₂(μ-S)(μ-SCH₂C₆H₄CH₂S)(μ-S)Pt₂(PPh₃)₄]²⁺. Arylation reactions of [Pt₂(μ-S)₂(PPh₃)₄] with halobenzenes and 2-bromoheterocyclic compounds (pyridine, thiophene) are also described.     

Synthetic and mechanistic studies on ruthenium dicarbonyl complexes containing PhP(CH2CH2CH2PCy2)2 (Cyttp) ligand

A synthetic and mechanistic study is reported on ligand substitution and other reactions of six-coordinate ruthenium(II) carbonyl complexes containing tridentate PhP(CH₂CH₂CH₂PCy₂)₂ (Cyttp). Carbonylation of cis-mer-Ru(OSO₂CF₃)₂(CO)(Cyttp) (1) affords [cis-mer-Ru(OSO₂CF₃)(CO)₂(Cyttp)]O₃SCF₃ (2(O₃SCF₃)) and, on longer reaction times, [cis-mer-Ru(solvent)(CO)₂(Cyttp)](O₃SCF₃)₂ (solvent = acetone, THF, methanol). 2(O₃SCF₃) reacts with each of NaF, LiCl, LiBr, NaI, and LiHBEt₃ to yield [cis-mer-RuX(CO)₂(Cyttp)]⁺ (X = F (3), Cl (4), Br (5), I (6), H (7)), isolated as 3-7(BPh₄). These conversions proceed with high stereospecificity to afford only a single isomer of the product that is assigned a structure in which the Ph group of Cyttp points toward the CO trans to X (anti when X = F, Cl, Br, or I; syn when X = H). Treatment of 2(O₃SCF₃) with NaOMe and CO generates the methoxycarbonyl complex [cis-mer-Ru(CO₂Me)(CO)₂(Cyttp)]⁺ (8), whereas addition of excess n-BuLi to 2(O₃SCF₃) in THF under CO affords mer-Ru(CO)₂(Cyttp) (9). The two ¹³C isotopomers [cis-mer-Ru(OSO₂CF₃)(CO)(¹³CO)(Cyttp)]O₃SCF₃ (2′(O₃SCF₃): ¹³CO trans to P_C; 2″(O₃SCF₃): ¹³CO cis to all P donors) were synthesized by appropriate adaptations of known transformations and used in mechanistic studies of reactions with each of LiHBEt₃, NaOMe/CO, and n-BuLi. Whereas LiHBEt₃ reacts with 2′(O₃SCF₃) and 2″(O₃SCF₃) to replace triflate by hydride without any scrambling of the carbonyl ligands, the corresponding reactions of NaOMe-CO are more complex. The methoxide combines with the CO cis to triflate in 2, and the resultant methoxycarbonyl ligand ends up positioned trans to the incoming CO in 8. A mechanism is proposed for this transformation. Finally, treatment of either 2′(O₃SCF₃) or 2″(O₃SCF₃) with an excess of n-BuLi leads to the formation of the same two ruthenium(0) isomers of mer-Ru(CO)(¹³CO)(Cyttp). These products represent, to our knowledge, the first example of a syn-anti pair of isomers of a five-coordinate metal complex.     

Comparative properties of fluorous phosphine ligand complexes: W(CO)5L. Crystal structure of W(CO)5P(C6H4-4-CH2CH2(CF2)7CF3)3

The compounds W(CO)₅P(C₆H₄-4-CH₂CH₂(CF₂)₇CF₃)₃ (1) and W(CO)₅P(CH₂CH₂(CF₂)₅CF₃)₃ (2) were synthesized in order to probe the electronic and physical effects of ligation by perfluorocarbon substituted tertiary phosphine ligands in a W(CO)₅L complex. The π-accepting ability of the fluorous phosphines was found to rank with non-fluorous comparators as P(CH₂CH₂(CF₂)₅CF₃)₃ > P(C₆H₄-4-CH₂CH₂(CF₂)₇CF₃)₃ > PPh₃ > P(p-tolyl)₃ > P(n-octyl)₃. The X-ray crystal structure of W(CO)₅P(C₆H₄-4-CH₂CH₂(CF₂)₇CF₃)₃ shows strong intermolecular association of fluorous components but confirms that the para fluorocarbon subtituents have an insignificant effect on the tungsten coordination environment. Partition coefficients (toluene/perfluoromethylcyclohexane) were measured for compounds 1 and 2.     

Synthesis of trialkyl[60]fullerene C60(CH2SiMe3)3H and its potassium and rhodium(I) complexes

The reaction of [60]fullerene with Me₃SiCH₂MgCl in 1,2-Cl₂C₆H₄/THF (1/1) under dry air afforded a bis-alkyl adduct, C₆₀(CH₂SiMe₃)₂ (1), in 54% yield. Treatment of 1 with Me₃SiCH₂MgCl in THF under argon then afforded a trialkyl[60]fullerene, C₆₀(CH₂SiMe₃)₃H (2), in 37% yield. Further treatment of 2 with KO^tBu gave a potassium salt, [K(thf)_n][C₆₀(CH₂SiMe₃)₃] (3), which was then converted to a C_s-symmetric Rh(I) complex, Rh[η⁵-C₆₀(CH₂SiMe₃)₃](1,5-cyclooctadiene) (4), in 91% yield.     

Synthesis and coordination of the bifunctionalized ylides Ph2P(CH2)n(Ph)2PCHCOOMe (n = 1, 2) and ketenylidene Ph2P(CH2)2(Ph)2PCCO to Pd and Pt complexes

In this paper it is reported the synthesis of the phosphonium salts [Ph₂P(CH₂)_n(Ph)₂PCH₂COOMe]Br (n = 1 (1), 2 (2)) and [Ph₂P(CH₂COOMe)(CH₂)_n(Ph)₂PCH₂COOMe]Br₂ (n = 3 (3)) derived from the reactions of the diphosphines dppm, dppe and dppp with methyl bromoacetate. By reaction of the monophosphonium salt of dppm and dppe with the strong base Na[N(SiMe₃)₂] the corresponding carbonyl stabilized ylides Ph₂P(CH₂)_n(Ph)₂PCHCOOMe (n = 1 (4), 2 (5)) were obtained. The Ph₂P(CH₂)₂(Ph)₂PCHCOOMe (5) ylide was reacted with Pd(II) and Pt(II) substrates. From these reactions were isolated exclusively complexes in which the ylide was chelated to the metal through the free phosphine group and the ylidic carbon atom. A further reaction of the Ph₂P(CH₂)₂(Ph)₂PCHCOOMe (5) ylide with 1.5 equiv. of Na[N(SiMe₃)₂] gives the bifunctionalized ketenylidene Ph₂P(CH₂)₂(Ph)₂PCCO (6) system. This cumulenic ylide reacts with Pt(II) complexes to form a chelated derivative in which IR and NMR spectra suggest the breaking of the CC bond of the -CCO group.     

Synthesis and characterisation of a trinuclear uranyl complex: Crystal structure of (CN3H6)5[(UO2)3O(OH)2(CH3COO)(C2O4)3]

The reaction of uranyl oxalate trihydrate with guanidinium acetate at room temperature in water yields known uranyl complex with composition (CN₃H₆)₂[UO₂(C₂O₄)₂(H₂O)]·H₂O as a first phase and a novel complex (CN₃H₆)₅[(UO₂)₃O(OH)₂(CH₃COO)(C₂O₄)₃] as a second. The second phase was investigated by means of IR spectroscopy and X-ray diffraction. The trinuclear discrete complex contains two symmetrically independent uranyl ions with a pentagonal bipyramid structure and has a nonplanar geometry. The distortion of its equatorial plane is caused by substitution of a monodentate bridge hydroxide anion by a bidentate bridge acetate-anion. The acidic ligands found in the complex are usually in competition for a place in coordination sphere of an uranyl ion, thus peculiarities of the complex formation are discussed in terms of ‘crystallochemical analysis’.     

Synthesis and characterization of uranyl(VI) and thorium(IV) complexes with phosphine oxides. The crystal structure of UO2(NO3)2(NO2-C6H4Ph2PO)2

Uranyl(VI) and thorium(IV) complexes of the type UO₂(NO₃)₂(L¹)₂, UO₂(NO₃)₂(L²)₂, UO₂(CH₃COO)₂L¹, UO₂(CH₃COO)₂L², Th(NO₃)₄(L¹)₂ and Th(NO₃)₄(L²)₂ (L¹ = (2-nitro)phenyl-bis-phenyl phosphine oxide, L² = triferrocenylphosphine oxide) are reported, together with their physico-chemical properties.The crystal structure of UO₂(NO₃)₂(L¹)₂ is also reported. The crystals are monoclinic, space group P2₁/n with a = 17.78(1), b = 13.88(1), c = 17.37(1) Å, β = 114.8(1)° for Z = 4. The uranium atom is 8-coordinated, the uranyl(VI) group being equatorially surrounded by an irregular hexagon of six oxygen atoms from two trans neutral ligands and two nitrato groups.     

Synthesis and structures of bimetallic silicon-containing imido alkylidene complexes of molybdenum Me2Si[CHMo(NAr)(ORF3)2]2 and PhVinSi[CHMo(NAr)(ORF3)2]2

Bimetallic alkylidene complexes of molybdenum (R_F3O)₂(ArN)MoCH-SiMe₂-CHMo(NAr)(OR_F3)₂ (1) and (R_F3O)₂(ArN)MoCH-SiPhVin-CHMo(NAr)(OR_F3)₂ (2) (Ar = 2,6-C₆H₃; R_F3 = CMe₂CF₃) have been prepared by the reactions of vinyl silicon reagents Me₂Si(CHCH₂)₂ and PhSi(CHCH₂)₃ with known alkylidene compound PhMe₂C-CHMo(NAr)(OR_F3)₂. Complexes 1 and 2 were structurally characterized. Ring opening metathesis polymerization (ROMP) of cyclooctene using compounds 1 and 2 as initiators led to the formation of high molecular weight polyoctenamers with predominant trans-units content in the case of 1 and predominant cis-units content in the case of 2.     

Metal-penicillamine interactions. Part 1. Preparation and crystal structure of a 1:1 complex of mercuric chloride with d-penicillamine, 2[μ3-Cl){HgSC(CH3)2CH(NH3)COO}3·3(μ2-Cl)· 2(H3O)·(H2O·Cl)3

A 1:1 complex of mercuric chloride with D-peniccillamine has been isolated and characterised as 2[(μ₃-Cl){HgSC(CH₃)₂CH(NH₃)COO}3]·3(μ₂-Cl)·2(H₃O)·(H₂O·Cl)₃. The compound crystallises in cubic space group P4₁32, with a = 18.679(5) Å and Z = 4. The structure, refined to R_F = 0.086 for 443 observed Mo-Kα diffractometer data, features a triply bridging chloride ion linking three equivalent [HgSC(CH₃)₂CH(NH₃)COO]⁺ units [Hg-Cl = 2.37(1) Å, Hg-Cl-Hg′ = 98.5(9)°]. The carboxylate groups of a pair of adjacent penicillamine ligands are strongly linked via a symmetrical O?H?O hydrogen bond of length 2.24(8) Å, and neighboring pyramidal trinuclear [μ₃-Cl){HgSC(CH₃)₂CH(NH₃)-COO}₃]²⁺ moieties are further connected by symmetrical chloride bridges [Hg-Cl = 3.06(2) Å; HgClHg′' = 79.6(7)°] to form a three-dimensional network. The voids in the lattice are filled by hydronium ions and novel planar cyclic hydrogen-bonded (H₂O·Cl^?)₃ rings of edge O-H?Cl = 2.46(4) Å.     

Reactions of Zr(C5H5)(6,6-dmch)(PMe3)2 and Zr(6,6-dmch)2(PMe3)2 (dmch=dimethylcyclohexadienyl) with CO and alkynes

The reactions of Zr(C₅H₅)(6,6-dmch)(PMe₃)₂ and Zr(6,6-dmch)₂(PMe₃)₂ (dmch=dimethylcyclohexadienyl) with CO lead to the selective replacement of one PMe₃ ligand by CO. Both carbonyl complexes have been structurally characterized. Additionally, the reaction of the latter complex with PhC₂SiMe₃ leads to a similar replacement of one PMe₃ ligand, involving simple coordination of the alkyne, rather than any coupling to the dmch ligand.     

Raman and infrared spectroscopic and theoretical studies of dinuclear rhenium and osmium complexes, M2(O2CCH3)4X2 (M = Re, Os; X = Cl, Br)

Infrared, far-infrared and Raman spectra of Re₂(O₂CCH₃)₄X₂ (X = Cl, Br) and Re₂(O₂CCD₃)₄Cl₂ have been recorded. Assignments of the vibrational spectra of Os₂(O₂CCH₃)₄Cl₂ and its deuterated derivative have been completed together with the Re complexes on the basis of normal-coordinate analysis. Force constant calculation was made for the acetate ion as well as for a four-atomic unit (with the CH₃ and CD₃ groups considered as point masses) using optimized masses of 16.7, 17.8, 20.5 and 21.6 for ¹²CH₃, ¹³CH₃, ¹²CD₃ and ¹³CD₃ groups, respectively. The force constants of the acetate ion have been adopted to the starting force field of the M₂(O₂CCH₃)₄X₂ type complexes. The metal-halide (0.889, 0.997 and 1.286 N cm⁻¹) and metal-metal stretching (3.32, 3.34 and 3.57 N cm⁻¹) force constants were obtained for Re₂(O₂CCH₃)₄Cl₂Re₂(O₂CCH₃)₄Br₂ and Os₂(O₂CCH₃)₄Cl₂ complexes, respectively. It was shown that the so-called diatomic approximation in most cases overestimates the M-M stretching force constants by 30-40%. Much better correlation has been obtained to fit these force constants, which produced values very close to those obtained by full normal-coordinate calculations. The Re-Re stretching force constants showed a reasonable correlation with the Re-Re bond distances for 18 rhenium complexes.     

Synthesis and characterization of complexes of the type [Pt(amine)4]I2 and trans-[Pt(CH3NH2)2(H3CNC(CH3)2)2]I2 by crystallography and multinuclear magnetic resonance spectroscopy

Complexes of the type [Pt(amine)₄]I₂ were synthesized and characterized mainly by multinuclear (¹⁹⁵Pt, ¹H and ¹³C) magnetic resonance spectroscopy. The compounds were prepared with different primary amines, but not with bulky amines, due to steric hindrance. In ¹⁹⁵Pt NMR, the signals were observed between −2715 and −2769 ppm in D₂O. The coupling constant ³J(¹⁹⁵Pt-¹H) for the MeNH₂ complex is 42 Hz. In ¹³C NMR, the average values of the coupling constants ²J(¹⁹⁵Pt-¹³C) and ³J(¹⁹⁵Pt-¹³C) are 18 and 30 Hz, respectively. The crystal structure of [Pt(EtNH₂)₄]I₂ was determined by X-ray diffraction methods. The Pt atom is located on an inversion center. The structure is stabilized by H-bonding between the amines and the iodide ions. The compound with n-BuNH₂ was found by crystallographic methods to be [Pt(n-BuNH₂)₄]₂I₃(n-BuNHCOO). The crystal contains two independent [Pt(CH₃NH₂)₄]²⁺ cations, three iodide ions and a carbamate ion formed from the reaction of butylamine with CO₂ from the air. When the compound [Pt(CH₃NH₂)₄]I₂ was dissolved in acetone, crystals identified as trans-[Pt(CH₃NH₂)₂(H₃CNC(CH₃)₂)₂]I₂ were isolated and characterized by crystallographic methods. Two trans bonded MeNH₂ ligands had reacted with acetone to produce the two N-bonded Schiff base Pt(II) compound.     

Ru2(CO)4(OOCR)2L2 sawhorse-type complexes containing axial 5-(4-pyridyl)-10,15,20-triphenylporphyrin ligands

The thermal reaction of Ru₃(CO)₁₂ with various carboxylic acids (benzoic, 4-hydroxyphenylacetic, ferrocenic, stearic, oleic, 4-(octadecyloxy)benzoic) in refluxing tetrahydrofuran, followed by addition of 5-(4-pyridyl)-10,15,20-triphenylporphyrin (L), gives the dinuclear complexes Ru₂(CO)₄(OOCR)₂L₂ (1: R = -C₆H₅, 2: R = -CH₂-p-C₆H₄OH, 3: R = -C₅H₄FeC₅H₅, 4: R = -(CH₂)₁₆CH₃, 5: R = -(CH₂)₇CHCH(CH₂)₇CH₃, 6: R = -p-C₆H₄O(CH₂)₁₇CH₃). Complexes 1-6 were characterised by IR, NMR, and ESI-MS as well as by elemental analysis. The UV-Vis spectra show the Soret band centred at 417 nm and the Q bands at 515, 550, 590 and 645 nm, respectively.     

Structure and reactivity of [Ru(2,3-Medpp)2Cl2]

The structure and reactivity of the complex [Ru(2,3-Medpp)₂Cl₂](PF₆)₂ (2,3-Medpp⁺=2-[2-(1-methylpyridiniumyl)]-3-(2-pyridyl)pyrazine) was investigated by X-ray diffraction (XRD), ¹H NMR, redox, and UV-Vis absorption measurements. X-ray analysis shows that crystals obtained from an acetonitrile-toluene solution contain the trans-Cl₂, trans-pyrazine isomeric form, while ¹H NMR and redox measurements on the main product of the synthetic workup indicate the presence of the trans-Cl₂, cis-pyrazine isomer. In the dark at 70 °C, the complex [Ru(2,3-Medpp)₂Cl₂]²⁺ reacts slowly in acetonitrile isomerizing to the cis-[Ru(2,3-Medpp)₂(CH₃CN)Cl]³⁺ species. Under ambient light in the presence of excess AgNO₃ the cis-[Ru(2,3-Medpp)₂(CH₃CN)₂]⁴⁺ species is obtained.     

Time-resolved infrared study of reactive species produced by flash photolysis of the hydroformylation catalyst precursor Co2(CO)6(PMePh2)2

Flash photolysis with time-resolved infrared (TRIR) spectroscopy was used to elucidate the photochemical reactivity of the hydroformylation catalyst precursor Co₂(CO)₆(PMePh₂)₂. Depending on reaction conditions, the net products of photolysis varied significantly. A model is presented that accounts for the net reactivity with two initial photoproducts, the 17-electron species Co(CO)₃(PMePh₂) and the coordinatively unsaturated dimer Co₂(CO)₅(PMePh₂)₂. No evidence was found for photochemical formation of Co₂(CO)₆(PMePh₂). Time-resolved spectroscopic studies allowed for the direct observation of transient species and for kinetics studies of certain reactions; for example, the reactions of Co(CO)₃PMePh₂ with CO and with PMePh₂ gave the respective rate constants 1.5 × 10⁵ and 1.2 × 10⁷ M⁻¹ s⁻¹, while the analogous reactions with Co₂(CO)₅(PMePh₂)₂ gave the rate constants of 2.6 × 10⁶ M⁻¹ s⁻¹ and 3.9 × 10⁷ M⁻¹ s⁻¹.