Copper thioether chemistry: Synthesis and X-ray crystal structures of binuclear copper(I) complexes [Cu2(L)] {L = [24]aneS8, [28]aneS8} incorporating octathia macrocycles

Reaction of L {L = [24]aneS₈, [28]aneS₈} with two molar equivalents of [Cu(NCMe)₄]X (X⁻ = ClO₄⁻, BF₄⁻, PF₆⁻) in MeCN affords the white binuclear copper(I) complexes [Cu₂(L)]²⁺. A single crystal X-ray structure determination of [CU₂([24]aneS₈)](BF₄)₂ shows two tetrahedral copper(I) centres, each of which is coordinated to four thioether sulphur-donors, Cu---S(1) = 2.263(3), Cu---S(4) = 2.363(3), Cu---S(7) = 2.349(3), Cu---S(10) = 2.261(3) Å. The Cu … Cu distance is 5.172(3) Å. A single crystal X-ray structure determination Of [CU₂([28]aneS₈)](ClO₄)₂ shows that this complex also contain two tetrahedral copper(I) centres, each coordinated to four thioether sulphur-donors, Cu---S(1) = 2.278(5), Cu---S(4) = 2.333(5), Cu---S(8) = 2.328(5), CU---S(11) = 2.268(5) Å. The Cu … Cu distance of 6.454(3) Å is greater than in [CU₂([24]aneS₈)]²⁺ , reflecting the greater cavity size in [CU₂([28]aneS₈)]²⁺. Cyclic voltammetry of [CU₂([24]aneS₈)]²⁺ and [CU₂([28]aneS₈)]²⁺ at platinum electrodes in MeCN (0.1 M ⁿBU₄NPF₆) shows irreversible oxidations at E_pa, = +0.88 V, +0.92 V vs Fc/Fc⁺, respectively, at a scan rate of 200 mV s⁻¹. Coulometric measurements in MeCN confirm these oxidations to be two-electron (one electron per copper) processes to give binuclear copper(II) species. Oxidation of the binuclear copper(I) precursors with H₂SO₄ or HNO₃ affords ESR-active copper(II) species which presumably incorporate SO₄²⁻ and NO₃⁻ bridges.     

2-(Phenyltelluromethyl)tetrahydrofuran (L) and 2-(2-{4-methoxyphenyl}telluroethyl)-1,3- dioxolane (L) and their palladium(II) and platinum(II) complexes

The nucleophile [ArTe⁻] generated in situ borohydride solution of Ar₂Te₂, reacts with 2-(chloromethyl) tetrahydrofuran and 2-(2-bromoethyl)-1,3-dioxolane resulting in L¹ and L², respectively. The complexes of palladium(II) and platinum(II) with L¹/L² having stoichiometries [MCl₂·L₂], [ML₂](ClO₄)₂, [(DPPE)ML₂](ClO)₄)₂, [(PPh₃)₂ML₂](ClO₄)₂ and [(phen)ML₂](ClO₄)₂ (where L = L¹/L² DPPE = Ph₂PC H₂CH₂PPh₂, PHEN = 1,10-phenanthroline and M = Pd/Pt) have been synthesized. IR, ¹H, ¹²⁵Te{¹H} and ³¹P{¹H} NMR and UV-vis spectral data of these species in conjunction with their molar conductance and molecular weight data have been used to authenticate the new species. In all complexes (1–20) the ligands L¹ and L² are coordinated through tellurium and in the complexes of formula [ML₂](ClO₄)₂ (M = Pd, Pt) the ligand is bidentate with the oxygen atom used in complexation. In solution, complexes PtCl₂L₂ exist as a mixture of cis and trans isomers whereas only the trans isomer was observed for the palladium analogues. The [(phen)PdL₂](ClO₄)₂(Q) quenches ¹O₂ readily. The plot of log [Q] vs time is linear. Mechanism compatible with the experimental observations is proposed.     

Synthesis of metallocenes of zirconium, hafnium, manganese, iron, tin, lead and half-sandwich complexes of rhodium and iridium containing the ligands (η-C5R4CR′2PMe2), where R and R′ may be H or Me

The dimethylphosphino substituted cyclopentadienyl precursor compounds [M(C₅Me₄CH₂PMe₂)], where M=Li⁺ (1), Na⁺ (2), or K⁺ (3), and [Li(C₅H₄CR′₂PMe₂)], where R′₂=Me₂ (4), or (CH₂)₅ (5), [HC₅Me₄CH₂PMe₂H]X, where X⁻=Cl⁻ (6) or PF₆⁻ (7) and [HC₅Me₄CH₂PMe₂] (8), are described. They have been used to prepare new metallocene compounds, of which representative examples are [Fe(η-C₅R₄CR′₂PMe₂)₂], where R=Me, R′=H (9); R=H and R′₂=Me₂ (10), or (CH₂)₅ (11), [Fe(η-C₅H₄CMe₂PMe₃)₂]I₂ (12), [Fe{η-C₅Me₄CH₂P(O)Me₂}₂] (13), [Zr(η-C₅R₄CR′₂PMe₂)₂Cl₂], where R=H, R′=Me (14), or R=Me, R′=H (15), [Hf(η-C₅H₄CMe₂PMe₂)₂]Cl₂] (16), [Zr(η-C₅H₄CMe₂PMe₂)₂Me₂] (17), {[Zr(η-C₅Me₄CH₂PMe₂)₂]Cl}{(C₆F₅)₃BClB(C₆F₅)₃} (18), [Zr{(η-C₅Me₄CH₂PMe₂)₂Cl₂}PtI₂] (19), [Mn(η-C₅Me₄CH₂PMe₂)₂] (20), [Mn{(η-C₅Me₄CH₂PMe₂B(C₆F₅)₃}₂] (21), [Pb(η-C₅H₄CMe₂PMe₂)₂] (23), [Sn(η-C₅H₄CMe₂PMe₂)₂] (24), [Pb{η-C₅H₄CMe₂PMe₂B(C₆F₅)₃}₂] (25), [Pb(η-C₅H₄CMe₂PMe₂)₂PtI₂] (26), [Rh(η-C₅Me₄CH₂PMe₂)(C₂H₄)] 29, [M(η,κP-C₅Me₄CH₂PMe₂)I₂], where M=Rh (30), or Ir, (31).     

Reactions of the cationic diruthenium carbonyl complex [Ru2(μ-dppm)2(CO)4(μ,η-O2CMe)] with bidentate ligands; intramolecularly assisted stereospecific synthesis via the second-sphere face-to-face π–π stacking interactions

The reactions of the diruthenium carbonyl complexes [Ru₂(μ-dppm)₂(CO)₄(μ,η²-O₂CMe)]X (X=BF₄⁻ (1a) or PF₆⁻ (1b)) with neutral or anionic bidentate ligands (L,L) afford a series of the diruthenium bridging carbonyl complexes [Ru₂(μ-dppm)₂(μ-CO)₂(η²-(L,L))₂]X_n ((L,L)=acetate (O₂CMe), 2,2′-bipyridine (bpy), acetylacetonate (acac), 8-quinolinolate (quin); n=0, 1, 2). Apparently with coordination of the bidentate ligands, the bound acetate ligand of [Ru₂(μ-dppm)₂(CO)₄(μ,η²-O₂CMe)]⁺ either migrates within the same complex or into a different one, or is simply replaced. The reaction of [Ru₂(μ-dppm)₂(CO)₄(μ,η²-O₂CMe)]⁺ (1) with 2,2′-bipyridine produces [Ru₂(μ-dppm)₂(μ-CO)₂(η²-O₂CMe)₂] (2), [Ru₂(μ-dppm)₂(μ-CO)₂(η²-O₂CMe)(η²-bpy)]⁺ (3), and [Ru₂(μ-dppm)₂(μ-CO)₂(η²-bpy)₂]²⁺ (4). Alternatively compound 2 can be prepared from the reaction of 1a with MeCO₂H–Et₃N, while compound 4 can be obtained from the reaction of 3 with bpy. The reaction of 1b with acetylacetone–Et₃N produces [Ru₂(μ-dppm)₂(μ-CO)₂(η²-O₂CMe)(η²-acac)] (5) and [Ru₂(μ-dppm)₂(μ-CO)₂(η²-acac)₂] (6). Compound 2 can also react with acetylacetone–Et₃N to produce 6. Surprisingly [Ru₂(μ-dppm)₂(μ-CO)₂(η²-quin)₂] (7) was obtained stereospecifically as the only one product from the reaction of 1b with 8-quinolinol–Et₃N. The structure of 7 has been established by X-ray crystallography and found to adopt a cis geometry. Further, the stereospecific reaction is probably caused by the second-sphere π–π face-to-face stacking interactions between the phenyl rings of dppm and the electron-deficient six-membered ring moiety of the bound quinolinate (i.e. the N-included six-membered ring) in 7. The presence of such interactions is indeed supported by an observed charge-transfer band in a UV–vis spectrum.     

Bis(η-pentamethylcyclopentadienyl)-and(ηcyclopentadienyl) (η-pentamethylcyclopentadienyl)-platinium dications: Pt(IV) metallocenes

Reaction of [Pt₂(η⁵-C₅Me₅)₂(η-Br)₃]³⁺(Br⁻)₃ with C₅R₅H (R = H,Me) in the presence of AgBF₄ gives the first platinocenium dications, [Pt(η⁵-C₅Me₅)(η⁵-C₅R₅)]²⁺(BF₄⁻ )₂. On electrochemical reduction, [pt(η⁵-C₅Me₅)₂]²⁺ yields [Pt(η⁴-C₅Me₅H)(η²-C₅Me₅)]+ BF₄⁻. kw]Cyclopentadienyl; Metallocenes; Platinum; Electrochemistry     

Reaction of the tetrasulphidomolybdenum(IV) complex LMo(NCS)(S4) with dicarbomethoxyacetylene: X-ray structure of LMo(NCS){S2C2(CO2Me)2} [L = hydrotris(3,5-dimethylpyrazolyl)borate]

The reaction of {HB(Me₂pz)₃}Mo(NCS)(S₄) [HB(Me₂pz)₃⁻ = hydrotris(3,5-dimethylpyrazolyl)borate anion] with dicarbomethoxyacetylene in refluxing toluene results in the formation of the brown, diamagnetic complex {HB(Me₂pz)₃}Mo(NCS){S₂C₂(CO₂Me)₂} (1) (the reactants above also yield 1 upon prolonged reaction in dichloromethane at 25°C), which has been characterized by X-ray crystallography. The mononuclear pseudo-octahedral complex contains a facially tridentate HB(Me₂pz)₃⁻ ligand, a monodentate N-bound NCS⁻ ligand, and a bidentate S₂C₂(CO₂Me)₂²⁻ ligand having a near planar MoS₂C₄ fragment and a SC=CS bond distance of 1.342(15) Å. Solutions of 1 are unstable in air and decompose to produce {HB(Me₂pz)₃}MoO₂(NCS) and {HB(Me₂pz)₃}MoO(NCS)₂.     

A new homobimetallic arenediyl diplatinum(II) unit as building block for macromolecular synthesis. X-ray crystal structure of [C6H2{CH2NMe2}2-1,5-{PtCl(PPh3)}2-2,4]

Treatment of the diaminobenzene [C₆H₄{CH₂NMe₂}₂-1,3] (NCN-H, 1) with one or two equivalents of cis-PtCl₂(DMSO)₂ leads to exclusive formation of the doubly cycloplatinated species [C₆H₄{CH₂NMe₂}₂-1,5-{PtCl(DMSO)}₂-2,4] (3), which upon addition of triphenylphosphine yields the bisphosphine adduct [C₆H₄{CH₂NMe₂}₂-1,5-{PtCl(PPh₃)}₂-2,4] (4). The X-ray molecular structure of 4 revealed the presence of highly distorted square planar Pt(II) centers which is caused by close proximity of the two phosphine donor ligands. Complexes of type 3 can be regarded as suitable starting materials for the directional build-up of larger macromolecular structures.     

Copper thioether chemistry: The synthesis and single crystal X-ray structures of [Cu2([18]aneS6)(NCMe)2](ClO4)2 and [Cu([9]aneS3)(AsPPh3)](ClO4)

Reaction of [18]aneS₆ with two molar equivalents of [Cu(NCMe)₄](ClO₄) in CH₂Cl₂-MeCN affords the binuclear copper(I) complex [Cu₂([18]aneS₆)(NCMe)₂](ClO₄)₂. The single crystal X-ray structure of the complex shows a centrosymmetric cation with two tetrahedral copper(I) centres each coordinated to three thioether S-donors of [18]aneS₆,Cu---S(1) = 2.3200(15), Cu---S(4) = 2.3415(16), Cu---S(7) = 2.3250(15) Å, and to one MeCN molecule, Cu---N(1) = 1.939(5) Å, to give an overall NS₃-donation at the metal centres. Additionally, S(7′) shows a long-range interaction, Cu …S(7′) = 3.318(2) Å thus distorting the coordination geometry of the metal ion towards trigonal bipyramidal. The metal-metal separation of 4.428(2) Å suggests that there is no significant interaction between the copper centres of the dimer. Reaction of [9]aneS₃ with one molar equivalent of [Cu(NCMe)₄](ClO₄) in refluxing MeCN in the presence of ligands, L, affords the adducts [Cu([9]aneS₃)L]⁺ (L = PPh₃, AsPh₃). The single crystal X-ray structure of the complex [Cu([9]aneS₃)(AsPh₃)](ClO₄) shows tetrahedral AsS₃ coordination at copper(I) with [9]aneS₃ bound facially to the metal centre, Cu---S = 2.303(6), Cu---As = 2.322(4) Å.     

Rhenium(I) methoxo carbonyl complexes containing tetraphosphine or triphosphine ligands; facile separation and X-ray crystallographic studies of d/l- and meso-[{Re2(μ-OMe)2(CO)6}2(μ,μ′-1,1,4,7,10,10-hexaphenyl-1,4,7,10-tetra-phosphadecane)]

Reaction of the activated mixture of Re₂(CO)_10, Me₃NO and MeOH with a 1:1 mixture of rac (d/l)- and meso-1,1,4,7,10,10-hexaphenyl-1,4,7,10-tetraphosphadecane (hptpd) yields a mixture of (d/l)- and meso-[{Re₂(μ-OMe)₂(CO)₆}₂(μ,μ′-hptpd)] 1. The diastereomers can be easily separated by selective dissolution of d/l-1 in benzene, and give clearly distinguishable ¹H- and ³¹P-NMR spectra. The fluxional behavior of d/l-1 in solution has been studied by variable-temperature ¹H- and ³¹P-{¹H}-NMR spectroscopy. The crystal structures of both d/l- and meso-1 have been determined. Both molecules consist of two {Re₂(μ-OMe)₂(CO)₆} moieties which are bridged by the two P---CH₂---CH₂---P moieties of the hptpd ligand. Whilst the molecules of meso-1 possess crystallographic i-symmetry, those of d/l-1 do not have any crystallographic symmetry. These diastereomers therefore give clearly distinguishable Raman spectra in the solid state. Reaction of tris[2-(diphenylphosphino)ethyl]phosphine (tdppep) with the activated mixture affords the complex [{Re₂(μ-OMe)₂(CO)₆}(μ,η²-tdppep)] 2, and the analogous reaction involving bis[2-diphenylphospinoethyl)phenylphosphine (triphos) gives [{Re₂(μ-OMe)₂(CO)₆}(μ,μ′,η³-triphos){Re₂(CO)₉}] 3 and [{Re₂(μ-OMe)₂(CO)₆}(μ,η²-triphos)] 4.     

Influence of the modification of the ligands on hex-1-ene hydroformylation catalyzed by [HRh{P(OPh)3}4] and [HRh(CO){P(OPh)3}3]. Catalytic activity of the sytem [HRh}P(OPh)3}4]+Cp2Zr(CH2PPh2)2

A study has been carried out of the catalytic activity of the systems formed by [HRh{P(OPh)₃}₄] or [HRh(CO){P(OPh)₃}₃] with the modifying ligands P(OPh)₃, PPh₃, diphos and Cp₂Zr(CH₂PPh₂)₂ in hydroformylation of hex-1-ene (at p = 5 bar). The best results were obtained with the system [HRh{P(OPh)₃}₄]+Cp₂Zr(CH₂PPh₂)₂ (75–85% yeild of aldehydes).     

Stabile Bis(η-alkin)MCl2-komplexe; Darstellung und reaktivität

The synthesis and reactivity of {(η⁵-C₅H₄SiMe₃)₂Ti(CCSiMe₃)₂} MCl₂ (M = Fe: 3a; M = Co: 3b; M = Ni: 3c) is described. The complexes 3 are accessible by the reaction of (η⁵-C₅H₄SiMe₃) ₂Ti(CSiMe₃)₂ (1) with equimolar amounts of MCl₂ (2) (M = Fe, Co, Ni). 3a reacts with the organic chelat ligands 2,2′-dipyridyl (dipy) (4a) or 1,10-phenanthroline (phen) (4b) in THF at 25°C to afford in quantitative yields (η⁵-C₅H₄SiMe₃)₂Ti(CSiMe₃)₂ (1) and [Fe(dipy)₂]Cl₂ (5a) or [Fe(phen)₂]Cl₂ (5b). 1/n[Cu^IHal]_n (6) or 1/n[Ag^IHal]_n (7) (Hal = Cl, Br) react with {(η⁵ -C₅H₄SiMe₃)₂Ti(CCSiMe₃)₂}FeCl₂ (3a), by replacement of the FeCl₂ building block in 3a, to yield the compounds {(η⁵-C₅H₄SiMe₃)₂Ti(C CSiMe₃)₂}Cu^IHal (8) or {(η⁵-C₅H₄SiMe₃)₂Ti(CSiMe₃)₂}Ag^IHal (9) (Hal = Cl, Br), respectively. In 8 and 9 each of the two Me₃SiCC-units is η²-coordinated to monomeric Cu^I Hal or Ag^IHal moieties. Compounds 8 and 9 can also be synthesized by the reaction of (η⁵-C₅H₄SiMe₃)₂ Ti(CSiMe₃)₂ (1) with 1/n[Cu^IHal]_n (6) or 1/n [Ag^IHal]_n (7) in excellent yields. All new compounds have been characterized by analytical and spectroscopic data (IR, ¹H-NMR, MS). The magnetic moments of compounds 3 were measured.     

Mercury(II) halide adducts of an olefinic double betaine: [{Hg2L2X4·6HgX2}n] [X = Cl, Br; L = cis-(p-Me2NC5H4N)2C2(COO)2]

Two polymeric mercury(II) halide adducts of an olefinic double betaine, cis-(p-Me₂NC₅H₄N⁺)₂C₂(COO⁻)₂ (L), have been prepared and characterized by X-ray crystallography. [{Hg₂L₂Cl₄·6HgCl₂}_n] (1) crystallizes in the monoclinic space group C2/c with Z = 4, and [{Hg₂L₂Br₄·HgBr₂}_n] (2) in the triclinic space group P with Z = 1. Complexes 1 and 2 are structurally similar, being composed of centrosymmetric fourteen-membered rings and nearly linear HgX₂ (X = Cl, Br) moieties that are further inter-linked by weak HgX [HgCl = 2.930–3.136(9) Å, HgBr = 3.057–3.310(6) Å] and HgO [2.64, 2.75(3) Å] bonds to generate a two-dimensional polymeric network.     

Synthesis, structure and nuclease activity of copper complexes of disubstituted 2,2′-bipyridine ligands bearing ammonium groups

A series of Cu(II) complexes of disubstituted 2,2′-bipyridine bearing ammonium groups [Cu(L¹⁻⁴)₂Br]⁵⁺ (1–4, L¹ = [5,5′-(Me₂NHCH₂)₂-bpy]²⁺, L² = [5,5′-(Me₃NCH₂)₂-bpy]²⁺, L³ = [4,4′-(Me₂NHCH₂)₂-bpy]²⁺, L⁴ = [4,4′-(Me₃NCH₂)₂-bpy]²⁺ and bpy = 2,2′-bipyridyl) were synthesized, of which complexes 1 and 4 were structurally characterized. Both coordination configurations of Cu(II) ions can be described as distorted trigonal bipyramid. The interaction between all complexes and CT-DNA was evaluated by thermal-denaturation experiments and CD spectroscopy. Results show that the complexes interact with CT-DNA via outside electrostatic interactions and their binding ability follows the order: 1 > 2 > 3 > 4. In the absence of any reducing agents, the cleavage of plasmid pBR322 DNA by these complexes was investigated and the hydrolysis kinetics of DNA was studied in Tris buffer (pH 7.5) at 37 °C. Obtained pseudo-Michaelis–Menten kinetic parameters: 15.0, 13.6, 2.01 and 1.69 h⁻¹ for 1, 2, 3 and 4, respectively, indicate that complexes 1 and 2 exhibit very high DNA cleavage activities. According to their crystal data, the high nuclease activity may be attributed to the strong interaction of the metal moiety and two ammonium groups with phosphate groups of DNA.     

The chemistry of compounds of the type Ru(η---C5Me4Et)(CO)2X (X=Cl, Br or I)

The title compounds react with unidentate ligands, L, containing either phosphorus or arsenic donor atoms to yield the corresponding compounds of the type Ru(η⁵---C₅Me₄Et)(CO)LX; with didentate phosphorus donor ligands the major species formed is the bridged complex {Ru(η⁵---C₅Me₄Et)(CO)X}₂{Ph₂P(CH₂)_nPPh ₂} n = 1, X = Br; n = 2, X = Cl). In contrast, unidentate ligands containing nitrogen donor atoms such as pyridine did not react with Ru(η⁵---C₅Me₄Et)(CO)₂Cl although reaction with 1,10-phenanthroline or diethylenetriamine yielded the ionic products [Ru(η⁵---C₅Me₄Et)(CO)L]⁺Cl⁻ (L = phen or (NH₂CH₂CH₂)₂NH). Reaction of Ru(η⁵---C₅Me₄Et)(CO)₂Br with AgOAc yielded the corresponding acetato complex Ru(η⁵---C₅Me₄Et)(CO)₂0Ac. Ru(η⁵--- C₅Me₄Et)(CO)₂X reacts with AgY (Y = BF₄ or PF₆) in either acetone or dichloromethane to give the useful solvent intermediates [Ru(η⁵---C₅Me₄Et)(CO)₂(solvent)]⁺Y⁻, which readily react with ligands L to yield ionic derivatives of the type [Ru(η⁵---C₅Me₄Et)(CO)₂L]⁺Y⁻ (where L = CO, NCMe, py, C₂H₄ or MeO₂CCCCO₂Me).     

Some additional aspects of versatile starting compounds for cationic organoiron complexes: molecular structure of the aqua complex [(η-C5Me4Et)Fe(CO)2(OH2)]BF4 and solution behavior of the THF complex [(η---C5R5)Fe(CO)2(THF)]BF4

The structures of the versatile starting compounds for organoiron complexes, the cationic aqua complex [(η⁵-C₅Me₄Et)Fe(CO)₂(OH₂)]BF₄ (1b) and the halide complexes (η⁵-C₅Me₅)Fe(CO)₂-I (2a), (η⁵-C₅Me₄Et)Fe(CO)₂-I (2b) and (η⁵-C₅Me₄Et)Fe(CO)₂-Cl (3b), are characterized by X-ray crystallography. Complex 1b [Fe---O: 2.022(8) Å and 2.043(9) Å, two independent molecules] is the first structurally characterized example of organoiron aqua complexes. Details of the synthetic procedures for the above complexes and the labile cationic THF complexes [η⁵-C₅R₅)Fe(CO)₂(THF)]BF₄ (4) are disclosed, and the dissociation equilibrium of 4 is confirmed by means of variable temperature ¹H-NMR as well as saturation transfer experiment.     

Hydrothermal syntheses and crystal structures of bimetallic cluster complexes [{Cd(phen)2}2V4O12]·5H2O and [Ni(phen)3]2[V4O12]·17.5H2O

The hydrothermal reactions of vanadium oxide starting materials with divalent transition metal cations in the presence of nitrogen donor chelating ligands yield the bimetallic cluster complexes with the formulae [{Cd(phen₂)₂V₄O₁₂]·5H₂O (1) and [Ni(phen)₃]₂[V₄O₁₂]·17.5H₂O (2). Crystal data: C₄₈H₅₂Cd₂N₈O₂₂V₄ (1), triclinic. a=10.3366(10), b=11.320(3), c=13.268(3) Å, =103.888(17)°, β=92.256(15)°, γ=107.444(14)°, Z=1; C₇₂H₁₃₁N₁₂Ni₂O_29.5V₄ (2), triclinic. a=12.305(3), b=13.172(6), c=15.133(4), =79.05(3)°, β=76.09(2)°, γ=74.66(3)°, Z=1. Data were collected on a Siemens P4 four-circle diffractometer at 293 K in the range 1.59° <θ<26.02° and 2.01°<θ<25.01° using the ω-scan technique, respectively. The structure of 1 consists of a [V₄O₁₂]⁴⁻ cluster covalently attached to two {Cd(phen)₂}²⁺ fragments, in which the [V₄O₁₂]⁴⁻ cluster adopts a chair-like configuration. In the structure of 2, the [V₄O₁₂]⁴⁻ cluster is isolated. And the complex formed a layer structure via hydrogen bonds between the [V₄O₁₂]⁴⁻ unit and crystallization water molecules.     

Synthesis, crystal structure and third-order non-linear optical property of heterobimetallic cluster compound [MoOICu3S3(2,2′-bipy)2]

Nest-shaped cluster [MoOICu₃S₃(2,2′-bipy)₂] (1) was synthesized by the treatment of (NH₄)₂MoS₄, CuI, (n-Bu)₄NI, and 2,2′-bipyridine (2,2′-bipy) through a solid-state reaction. It crystallizes in monoclinic space group P2₁/n, a=9.591(2) Å, b=14.820(3) Å, c=17.951(4) Å, β=91.98(2)°, V=2549.9(10) ų, and Z=4. The nest-shaped cluster was obtained for the first time with a neutral skeleton containing 2,2′-bipy ligand. The non-linear optical (NLO) property of [MoOICu₃S₃(2,2′-bipy)₂] in DMF solution was measured by using a Z-scan technique with 15 ns and 532 nm laser pulses. The cluster has large third-order NLO absorption and the third-order NLO refraction, its ₂ and n₂ values were calculated as 6.2×10⁻¹⁰ and −3.8×10⁻¹⁷ m² W⁻¹ in a 3.7×10⁻⁴ M DMF solution.     

Attempts at stepwise reduction of the carbon-nitrogen triple bond of a nitrile at two metal centres: study of the reactivity of [(CO)(PPh3)2Re( (μ-NCHPh)Ru(PPh3) 2(PhCN)] towards tetrafluoroboric acid and dihydrogen

The reaction of [(CO)PPh₃)₂Re(μ-H)₂(μ-NCHPh)Ru(PPh₃)₂(PhCN)] (2) with HBF₄-Me₂O generates [(CO)PPh₃)₂Re(μ- H)₂(μ,η¹,η²HNCHPh)Ru(PPh₃)₂(PhCN)][BF₄] (3). Monitoring the reaction by NMR spectroscopy shows the intermediate formation of [(CO)(PPh₃)₂ HRe(μ-H)₂(μ-NCHPh)Ru(PPh₃)₂(PhCN)][BF₄] (4). Attempted reduction of the imine ligand by a nucleophile (H⁻ or CN⁻) failed, regenerating 2. Under dihydrogen at 50 atm, 3 is slowly transformed into [(CO)(PPh₃)₂HRe(μ-H)₃Ru(PPh₃)₂(PhCN)][BF₄] (5) with liberation of benzyl amine.     

Synthesis and application of diphenylbis (3,5-dimethylpyrazol-1-yl)methane to form η-arene complexes of molybdenum

The neutral nitrogen-bidentate ligand, diphenylbis(3,5-dimethylpyrazol-1-yl)methane, Ph₂CPz′₂, can readily be obtained by the reaction of Ph₂CCl₂ with excess HPz′ in a mixed-solvent system of toluene and triethylamine. It reacts with [Mo(CO)₆] in 1,2-dimethoxyethane to give the η²-arene complex, [Mo(Ph₂CPz′₂)(CO)₃] (1). This η²-ligation appears to stabilize the coordination of Ph₂CPz′ ₂ in forming [Mo(Ph₂CPz′₂)(CO)₂(N₂C₆H₄NO₂-p)][BPh₄] (2) and [Mo(Ph₂CPz′₂)(CO)₂(N₂Ph)] [BF₄] (3) from the reaction of 1 with the appropriate diazonium salt but the stabilization seems not strong enough when [Mo{P(OMe)₃} ₃(CO)₃] is formed from the reaction of 1 with P(OMe)₃. The solid-state structures of 1 and 3 have been determined by X-ray crystallography: 1-CH₂Cl₂, monoclinic, P2₁/n, a = 11.814(3), b = 11.7929(12), c = 19.46 0(6) Å, β = 95.605(24)°, V = 2698.2(11) ų, Z = 4, D_calc = 1.530 g/cm³ , R = 0.044, R_w = 0.036 based on 3218 reflections with I > 2σ(I); 2 (3)-1/2 hexane-1/2 CH₃OH-1/2 H₂O-1 CH₂Cl₂, monoclinic, C2/c, a = 41.766(10), b = 20.518(4), c = 16.784(3) Å, β = 101.871(18)°, V = 14076(5) ų, Z = 8, D_calc = 1.457 g/cm³, R = 0.064, R_w = 0.059 based on 5865 reflections with I > 2σ(I). Two independent cations were found in the asymmetric unit of the crystals of 3. The average distance between the Mo and the two η²-ligated carbon atoms is 2.574 Å in 1 and 2.581 and 2.608 Å in 3. The unfavourable disposition of the η²-phenyl group with respect to the metal centre in 3 and the rigidity of the η²-arene ligation excludes the possibility of any appreciable agostic C---H → Mo interaction.     

Oxidative addition of 2,2′-dipyridyl disulfphide to the cluster [Os3(CO)10(MeCN)2]

The cluster [Os₃(CO)₁₀(MeCN)₂] reacts with 2,2′-dipyridyl disulphide (1, pySSpy) to give a range of oxidative addition products which were separated by TLC on silica and crystallization : [Os₃(pyS)₂(CO)₁₀] (2), [Os₃(pyS)₂(CO)₉] (3), [Os₂(pyS)₂(CO)₆] (4) and [Os(pyS)₂(CO)₂] (5), together with some of the hydride [Os₃H(pyS)(CO)₉] (6), which is not an expected oxidative addition product. The X-ray crystal structures of compounds 2, 3, 4 and 6 (compounds 2 and 6 occurring within a single crystal), together with the known structure of compound 5, reveal several modes of pyS bonding : chelating pyS, μ₂-pyS (both sulphur-bonded and nitrogen, sulphur-bonded) and μ₃-pyS.