The synthesis and crystal structure of a trinuclear molybdenum cluster compound [Mo3(μ-O)(μ-S)3(μ(μ-OAc)2(dtp)2·(Py)]·0.5H2O

[Mo₃,OS₃(dtp)₄(H₂O)] reacts with NaOAc·3H₂O in Py to give the title compound. The crystal data are as follows: [Mo₂OS₃)(OAc)₂(dtp)₂·Py]?0.5H,O(dtp = [S₃P(OC₂H₅)₂]^?, Py = C₅H₅N); M = 976.64; triclinic; space group P1 ; a=11.704(5), b=14.169(7), c= 11.688 (5) Å α=109.94(4) β = 91.53(4), γ = 91.93(4)°; V= 1819(1) Ų; Z=2; D_c = 1.78 g·cm^?3 λ(Mo Kα) = 0.71069 Å μ=15.15 cm^?1; F(000) = 970 T=296 K; final R=0.071 for 1652 reflections with I>3σ(I). In the molecule, the [Mo₃OS₃] core is surrounded by two bridging OAc groups and two terminal chelate dtp groups attached to the {Mo₃} triangle in a symmetric style, and the Py ligand is coordinated to the Mo atom at the apex of {Mo₃} triangle with the nitrogen. This novel configuration is obtained for the first time with Mo—N bond length being 2.27 (2) Å and three Mo—Mo bond lengths 2.584 (4), 2.587 (4) and 2.657(4) Å, respectively. As a whole, the molecule has a virtual C₂ symmetry.     

The designed synthesis and characterization of two novel heterometallic trinuclear incomplete cubane-like clusters [(CH3CH2)4N]{(M2CuS4)}(S2C2H4)2(PPh3) (M = Mo, W)

Two novel heterometallic trinuclear incomplete cubane-like clusters [(CH₃CH₂)₄N][{M₂CuS₄}(edt)₂(PPh₃)] (M = Mo, W) have been synthesized by reaction of [(CH₃CH₂)₄N]₂[M₂S₄(edt)₂] (M = Mo, W) with Cu(PPh₃)₂(dtp) [where edt is 1,2-ethane-dithiolato ligand, dtp is S₂P(OCH₂CH₃)₂⁻]. The two crystals are isomorphous in space group P1 (No. 1). The unit cell contains two independent molecules, but the two discrete anions have the same orientation for the PPh₃ ligands along one axis so the space group is undoubtedly non-centrosymmetric. The discrete anion contains two edt ligands and one PPh₃ ligand attached to one incomplete cubane-like cluster core {M₂CuS₄}³⁺ (M = Mo, W). The bond lengths of Mo---Mo[W---W] and the two Mo---Cu[W-Cu] are 2.852(2)[2.844(1)], 2.802(2)[2.765(3)], 2.760(2)[2.762(3)] Å, respectively. The M ₂S₄(edt)₂ (M = Mo, W) moiety remains almost unchanged, except that for the compound 1 the Mo=S double bond length elongates from av. 2.10 to av. 2.165 Å. The title clusters provide a new type of unsymmetric μ₂-bridging sulphido ligand. The incomplete cubane-like cluster core {Mo₂CuS₄}³⁺ of compound 1 is distorted because the two Cu---μ₂---S bond lengths are significantly different (2.313 Å and 2.409 Å), but the core {W₂CuS₄}³⁺ of compound 2 has approximately C_s symmetry. The IR spectra of the two title clusters and two starting materials are assigned.     

Three Heterometallic Mo–M′ Cubane-Like Tetranuclear Cluster Compounds (M′=Cu, Pb, Sb): Synthesis, Structure and Third-Order NLO Property

Three new heterometallic tetranuclear cluster compounds with a [Mo₃YS₃M] cubane-like cluster core (M=Cu, Pb, Sb; Y=O, S), [Mo₃OS₃(CuI)(-OAc)₂(dtp)₂(DMF)] (1), (dtp=S₂P(OC₂H₅)^– ₂), [Mo₃OS₃(PbI₃)(dtc)₃(py)₃] (2) (dtc=S₂CN(C₂H₅)^– ₂), [Mo₃S₄(SbI₃)(dtcpyr)₄(py)]·2H₂O (3) (dtcpyr=S₂CNC₄H^– ₈) have been synthesized and structurally characterized by IR, Raman, UV–Vis, ¹H NMR, ¹³C NMR spectroscopies and single-crystal X-ray diffraction studies. Their structure and bonding features are discussed. Compounds 1 and 2 show a good third-order optical nonlinearity, as measured by degenerate four-wave mixing technique.     

The reactivities of Mo cluster — A selective substitution reaction of the bridging (dtp) ligand and the crystal structure of {Mo3S4(μ-O2CR)(dtp)3(Py)}

The reaction of trinuclear molybdenum cluster {Mo₃S₄(μ-dtp) (dtp)₃ (H₂O)} 1 [dtp= S₂P(OEt)₂] with RCO₂Na (R?H, CH₃) in the presence of Py gave the black compounds {Mo₃S₄ {μ-O₂ CR) (dtp)₃ (Py)} (2, R?H, 3, R?CH₃). Both compounds are characterized by X-ray crystallography. It is shown that crystals 2 and 3 belong to space group P&1bar; with Z=2 and a=10.519(2), b= 12.121(2), c=15.757(2)Å, α=93.27(1), β=94.63(1), γ = 105.22(1)°, V= 1925 ų for crystal 2, whereas a=9.556 (2), b=14.067(7), c=15.914 (9) Å, α=101.41 (4), β=101.44(4), γ-74.26(3)°, V=1994ų for crystal 3. The final R factors are 0.041 and 0.048 for crystal 2 and 3 respectively. The structure analysis indicates that (O₂CR)^? ligand selectively substitutes the bridging (dtp) ligand. This type of Mo, cluster molecule where structure contains two species of bidentate ligand is for the first time to be obtained by us.     

Synthesis and crystal structure of an ionic cluster {[Mo_3(μ_3-O)(μ-S)_3(dtp)_3(py)_3][CdI(dtp)_2]}

A new cluster compound {[Mo3(μ3-O)(μ-S)3(dtp)3(py)3][CdI(dtp)2]} (dtp=S2P(O-was obtained from the reaction of (Mo3OS3(dtp)4(H2O)] with a CdI2-Bu4NI mixture.The molecular structure is composed of a cluster cation [Mo3OS3(dtp)3(py)3]+ and the complex anion [CdI(dtp)2]-Crystal data:Triclinic,space group P1 with cell parameters a=1.4672(7),b=1.5356(5),c=1.6806(5) nm,α=74.59(3),β=67.89(4),7=78.86(3)°,V=3.364(2) nm3,and Z=2,least-squares refinement of 8941 reflections gives a final agreement factor of R=0.052,Rw=0.065.     

A dinuclear molybdenum cluster containing i-mnt ligand: synthesis and crystal structure of [Mo_2S_4(i-mnt)_2] (Et_4N)_2

A dinuclear molybdenum(V) cluster compound (Et4N)2[Mo2S4(i-mnt)2] (i-mnt=l,l-dicyanoethylene-2,2-dithiol, (S2C=C(CN)2]2-) has been prepared by the ligand substitution reaction of Mo2S4(iso-pr2dtp)2 (iso-pr2dtp=S2P(OC3H7)2-) with K2(i-mnt) in the presence of Bt4NI. This cluster was characterized by inrrared spectrum, UV-Vis spectrum and single crystal structure analy-sis. The cluster anion [Mo2S4(i-mnt)2]2- possesses C, symmetry with a crystallographic mirror plane through two bridging S atoms. By the S....S supramolecular interactions between two adjacent cluster anions the [Mo2S4(i-mnt)2]2- anions are linked to form infinite chains along the b axis. Crystal data: monoclinic, space group C2/m, a=1.8748(6), b=1.5360(4), c=1.4322(5) nm, ,β=112.02(2)°, V=3.823(4) nm3, Z=4, Dc=1.50 g/cm3. The final R=0.038 and .RW=0.053 for 3015 observed unique reflections.     

Reactions of M3Te7 (M = Mo, W) clusters with electrophilic reagents: Chalcogen exchange in the Te2 ligand and the first complexes of (TeS)

Reactions of triangular telluride-bridged Mo and W clusters [M₃(μ₃-Te)(μ₂-Te₂)₃(dtp)₃]⁺ (M = Mo, W; dtp = (EtO)₂PS₂) with S₂Cl₂ or Br₂ lead to Te/S exchange in the Te₂ ligands, with the formation of complexes with a novel TeS²⁻ ligand. Reaction of [W₃(μ₃-Te)(μ₂-Te₂)₃(dtp)₃]⁺ with Br₂ or S₂Cl₂ gives a mixture of complexes formulated as [W₃Te_4.25S_2.75(dtp)₃]⁺ and [W₃Te_4.30S_2.70(dtp)₃]⁺, respectively, on the basis of X-ray structural analysis. Reaction of the Mo homolog, namely [Mo₃(μ₃-Te)(μ₂-Te₂)₃(dtp)₃]⁺, with S₂Cl₂ gives rise to [Мо₃Te_4.74S_2.26((EtO)₂PS₂)₃]⁺. Electrospray ionization mass spectrometry (ESI-MS) complements the information gathered from X-ray analysis regarding the degree of Te by S substitution; moreover, detailed insights on the regioselectivity of such replacement are also obtained from ESI-MS analysis. These experimental evidences indicate that Te by S replacement in W complexes display high regioselectivity (as evidenced by the exclusive formation of a W₃Te₄S₃⁴⁺ core), the equatorial Te ligands being preferentially replaced over the Te_ax and μ₃-Te ligands. Conversely, for the Mo homologs, a broad distribution of Mo₃Te_7−xS_x⁴⁺ cluster species ranging from x = 0 to 6 is observed. Bond distance analysis as well as crystal packing trends as a function of the cluster core M₃Te_7−xS_x⁴⁺ (M = Mo, W; x = 0–6) composition are also reported.     

Synthesis, Structure, and 31P NMR of Sulfur/Oxygen-Bridged Incomplete Cubane-Type Molybdenum and Tungsten Clusters with Triphenylphosphine Ligands

Sulfur/oxygen-bridged incomplete cubane-type triphenylphosphine molybdenum and tungsten-clusters [Mo₃S₄Cl₄(H₂O)₂(PPh₃)₃]·3THF (1A), [Mo₃S₄Cl₄(H₂O)₂(PPh₃)₃]·2THF (2A), [Mo₃OS₃Cl₄(H₂O)₂(PPh₃)₃]·2THF (1B), and [W₃S₄Cl₄(H₂O)₂(PPh₃)₃]·2THF (1C) were prepared from the corresponding aqua clusters and PPh₃ in THF/MeOH. On recrystallization from THF, procedures with and without addition of hexane to the solution gave 1A and 2A, respectively, while the procedures gave no effect on the formation of 1B and 1C. Crystallographic results obtained are as follows: 1A: monoclinic, P2₁/n, a=17.141(4) Å, b=22.579(5) Å, c=19.069(4) Å, =96.18(2)°, V=7337(3) ų, Z=4, R(R _w)=0.078(0.102); 1C: monoclinic, P2 ₁/c, a=12.635(1) Å, b=20.216(4) Å, c=27.815(3) Å, =96.16(1)°, V=7062(2) ų, Z=4, R(R _w)=0.071(0.083). If the phenyl groups are ignored, the molecule [Mo₃S₄Cl₄(H₂O)₂(PPh₃)₃] in 2A has idealized CS symmetry with the mirror plane perpendicular to the plane determined by the metal atoms, while the molecule in 1A does not have the symmetry. The tungsten compound 1C is isomorphous with the molybdenum compound 2A. ³¹P NMR spectra of 1A, 2A, and 1C were obtained and compared with similar clusters with dmpe (1,2-bis(dimethylphosphino)ethane) ligands.     

Preparation and surface photoelectric properties of Fe(II/III) complexes

Four Fe(II/III) supramolecules, {[Fe(Hpdc)₂(H₂O)₂]·2H₂O} (1), [Fe(HImbc)₂(H₂O)₂] (2), [Fe(phen)₂(CN)₂]·CH₃CH₂OH·2H₂O (3), K[Fe(tp)₂]·SO₄ (4) (H₂pdc = 2,5-Pyridinedicarboxylic acid, H₂Imbc = 4,5-Imidazoledicarboxylic acid, phen = 1,10-phenanthroline, tp⁻ = poly(pyrazolyl)borate), were synthesized by hydrothermal and room temperature stirring methods. They were characterized by single crystal X-ray diffraction, surface photovoltage spectroscopy (SPS), field-induced surface photovoltage spectroscopy (FISPS), electron paramagnetic resonance (EPR), UV–Vis absorption spectra (UV–Vis), infrared spectra (IR) and element analysis. The structural analyses indicate that complex (1) is a supramolecule with 2D structure connected by hydrogen bonds. Complex (2) is a supramolecule with hydrogen-bonded 3D structure. Complexes (3) and (4) are both 1D supramolecules connected by hydrogen bonds. The electronic state of central metal Fe(II) ions in complexes (1) and (2) is d⁶ with FeN₂O₄ coordination mode, lying in weaker distorted octahedral field. The electronic state of Fe(II) ion in complex (3) is d⁶ with Fe(CN)₂N₄ mode in the strong distorted octahedral field. The electronic state of Fe(III) ion in complex (4) is d⁵ with FeN₆ mode, lying in the strong octahedral field. The micro-environment of Fe(II/III) ions in the four complexes is further investigated by EPR. The SPS of four complexes all exhibit photovoltage responses in the range of 300–700 nm. This indicates that they all possess certain photoelectric conversion capability. The effects of component, structure, type of ligands of the complexes, valence state and coordination micro-environment of the central metal ions on the SPS were discussed. Furthermore, the SPS and UV–Vis absorption spectra were interrelated.     

Synthesis and characterization of some novel ruthenium(II) complexes containing thiolate ligands

Reactions of the ruthenium complexes [RuH(CO)Cl(PPh₃)₃] and [RuCl₂(PPh₃)₃] with hetero-difunctional S,N-donor ligands 2-mercapto-5-methyl-1,3,5-thiadiazole (HL¹), 2-mercapto-4-methyl-5-thiazoleacetic acid (HL²), and 2-mercaptobenzothiazole (HL³) have been investigated. Neutral complexes [RuCl(CO)(PPh₃)₂(HL¹)] (1), [RuCl(CO)(PPh₃)₂(HL²)] (2), [RuCl(CO)(PPh₃)₂(HL³)] (3), [Ru(PPh₃)₂(HL¹)₂] (4), [RuCl(PPh₃)₃(HL²)] (5), and [RuCl(PPh₃)₃(HL³)] (6) imparting κ²-S,N-bonded ligands have been isolated from these reactions. Complexes 1 and 4 reacted with diphenyl-2-pyridylphosphine (PPh₂Py) to give neutral κ¹-P bonded complexes [RuCl(CO)(κ¹-P-PPh₂Py)₂(HL¹)] (7), and [Ru(κ¹-P-PPh₂Py)₂(HL¹)₂] (8). Complexes 1-8 have been characterized by analytical, spectral (IR, NMR, and electronic absorption) and electrochemical studies. Molecular structures of 1, 2, 4, and 7 have been determined crystallographically. Crystal structure determination revealed coordination of the mercapto-thiadiazole ligands (HL¹-HL³) to ruthenium as κ²-N,S-thiolates and presence of rare intermolecular S-S weak bonding interaction in complex 1.     

Synthesis and structure of an open-type trinuclear molybdenum cluster compound[Mo_3(μ_3-S)(μ-S)_2-(μ-OAc)(S_2CNC_4H_8)_3(O)_2]·0.5CH_2Cl_2·2H_2O

The title compound was prepared by the reaction of Mo_3S_4(dtp)_4(H_2O)[ctp=S_2P(OEt)_2]with NaOAc·3H_2O and C_4H_8NCS_2NH_4.Crystallographic data:[Mo_3(μ_3-S)(μ-S)_2(μ-OAc)-(S_2CNC_4H_8)_3(O)_2]·0.5CH_2CI_2·2H_2O,Mr=980.18,triclinic,space group P,α=12.360(3),b=16.653(6),c=9.206(2)A,α=101.97(2),β=108.32(2),γ=86.14(3)°.V=1759.6(9)A~3,Z=2,Dc=1.85 g/cm~3,F(000)=962,μ(Mo K_α)=16.53 cm~(-1).Final R=0.044 for 4301 reflections with I≥3σ(I).This compoundmay be regarded as a mixed-valent trinuclear molybdenum cluster{Mo_2(V)Mo(Ⅳ)(μ_3-S)(μ-S)_2-(μ-OAc)(S_2CNC_4H_8)_3(O)_2}.The Mo-Mo distances are 2.783(1),2.833(1)and 3.374(2)A in the Mo_3non-equilateral triangle and there exist only two Mo-Mo bonds.The cluster was obtained by oxi-dation and ligand substitution of{Mo_3(μ_3-S)(μ-S)_3[μ-S_2P(OEt_2)][S_2P(OEt)_2]_3(H_2O)}.     

Cubane-Type Molybdenum-Zinc or -Cadmium Mixed-Metal Clusters with Diethyldithiophosphate or Nitrilotriacetate Ligands

The reactions of sulfur-bridged clusters, [Mo₃( ₃-S)(-S)₃(-dtp)(dtp)₃(CH₃CN)] (1) in acetonitrile or [Mo₃( ₃-S)(-S)₃(Hnta)₃]^2– (2) in pure water, with zinc or cadmium metal result in the formation of three novel molybdenum-zinc or molybdenum-cadmium mixed-metal clusters, [Zn{( ₃-S)₄Mo₃(-dtp)(dtp)₃(CH₃CN)}₂] (3), [Cd{( ₃-S)₄Mo₃(-dtp)(dtp)₃(CH₃CN)}₂] (4), and [Cd{( ₃-S)₄Mo₃(Hnta)₃}₂]^4– (5), respectively. The X-ray crystal structures of 1·H₂O(1), 3, 4, and [Co(H₂O)₆]₂ 5·22H₂O (5) were determined, and the existence of the sandwich cubane-type cores Mo₃S₄MS₄Mo⁸⁺ ₃ cores (M=Zn, Cd) in 3, 4, and 5 verified. By the change of the ligands, the peak positions at the longest wavelength in the electronic spectra are distinctly different from each other between 4 (856 nm) and 6 (1235 nm). The electronic structures of 3, 4, and 5 have been calculated by Discrete Variational (DV)-X method.     

Cross-linking nanostructured spherical capsules as building units by crystal engineering: related chemistry

The compound [Mo₇₂Fe₃₀O₂₅₂(CH₃COO)₁₀{Mo₂O₇(H₂O)}{H₂Mo₂O₈(H₂O)}₃ (H₂O)₉₁]·ca. 140 H₂O 3≡3a·ca. 140 H₂O, an important educt for an unusual solid state reaction, can now be obtained easily by reacting (NH₄)₄₂[{Mo^V₂O₄(CH₃COO)}₃₀{(Mo)Mo₅O₂₁(H₂O)₆}₁₂]·10 CH₃COONH₄·ca. 300 H₂O 1 with FeCl₃·6 H₂O in water. Interestingly, the freshly precipitated crystals of 3 contain discrete spherical clusters of the type {Mo^VI₇₂Fe^III₃₀} with as yet unprecedented 30×5 unpaired electrons (S=150/2 at room temperature). Upon drying 3, its cluster units 3a get covalently linked to form layers in a step by step solid state reaction, according to the scheme described below, resulting finally in the crystalline reaction product [H₄Mo₇₂Fe₃₀O₂₅₄(CH₃COO)₁₀{Mo₂O₇(H₂O)}{H₂Mo₂O₈(H₂O)}₃(H₂O)₈₇]·ca. 80 H₂O 44a·ca. 80 H₂O. The linking process at the Fe sites follows the well known inorganic condensation process leading to Fe^III polycations in aqueous solution according to the scheme Fe(OH₂)+(H₂O)Fe Fe(OH)+(H₂O)Fe Fe–O–Fe and thus is based on a type of crystal engineering with nanostructured spherical building blocks. This process does not allow chaotic characteristics in contrast to the mentioned polycation formation. Careful investigation leads to the identification of an intermediate 5 containing clusters 5a — with the same cluster composition as 3a and 4a — in the closest possible non-covalent contact. The related materials are of tremendous interest for magnetochemistry (nano-magneto-technology).

     

Cubane pyridine-acetylacetonate cluster complexes with the M<Subscript>3</Subscript>CuS<Stack><Subscript>4</Subscript><Superscript>5+</Superscript></Stack> core (M = Mo,W)

The reactions between [Mo₃(μ₃-S)(μ₂-S)₃(Acac)₃(Py)₃]PF₆ (HAcac is acetylacetone, Py is pyridine) and CuX (X = Cl, I, SCN) afford heterometallic cubane clusters [Mo₃(CuX)(μ₃-S)₄(Acac)₃(Py)₃]PF₆. The structures of two new compounds, [Mo₃(CuCl)S₄(Acac)₃(Py)₃]PF₆ · 3.25CH₂Cl₂ · 0.5C₆H₅CH₃ and [Mo₃(CuI)S₄(Acac)₃(Py)₃]PF₆ · 4C₆H₆, are determined by X-ray diffraction analysis. All synthesized compounds are characterized by elemental analysis and IR spectra. According to the vibrational spectra, the thiocyanate complex in the solid state is a mixture of the bond isomers [Mo₃(CuNCS)S₄(Acac)₃(Py)₃]PF₆ and [Mo₃(CuSCN)S₄(Acac)₃(Py)₃]PF₆, whereas in solution this complex exists as a isothiocyanate form.     

Coordination modes of 2-hydroxynicotinic acid in second- and third-row transition metal complexes

The new Pd(II), Pt(II), Re(V), Mo(VI) and W(VI) complexes of 2-hydroxynicotinic acid (H₂nicO), trans-[PdCl(HnicO)(PPh₃)₂]·0.75CH₃CN (1), K[PdCl(HnicO)₂]·H₂O (2), [Pd(HnicO)₂(bipy)] (3), cis-[PtCl(HnicO)(PPh₃)₂]·0.75CH₃OH·0.5H₂O (4), [PtCl(HnicO)(bipy)] (5), cis-[ReOI₂(HnicO)(PPh₃)] (6), Na₂[Mo₂O₆(HnicO)₂]·5H₂O (7), Na₂[Mo₄O₁₂(HnicO)₂]·2H₂O (8) and Na₂[W₂O₆(HnicO)₂]·5H₂O (9) have been prepared. The crystal structures of 1 and 4, were determined by X-ray diffraction and show the HnicO⁻ ligand coordinated to palladium or platinum through the nitrogen atom only. Infrared, Raman, ¹H and ¹³C{¹H} NMR spectroscopic data for the complexes are presented and are in agreement with the crystallographic results.     

Bio-catalysts and catalysts based on ruthenium(II) polypyridyl complexes imparting diphenyl-(2-pyridyl)-phosphine as a co-ligand

Reactions of the ruthenium complexes [Ru(κ³-tpy)(PPh₃)Cl₂], [Ru(κ³-tptz)(PPh₃)Cl₂] and [Ru(κ³-tpy)Cl₃] [tpy = 2,2′:6′,2′′-terpyridine; tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine] with diphenyl-(2-pyridyl)-phosphine (PPh₂Py) have been investigated. The complexes [Ru(κ³-tpy)(PPh₃)Cl₂] and [Ru(κ³-tptz)(PPh₃)Cl₂] reacted with PPh₂Py to afford [Ru(κ³-tpy)(κ¹-P-PPh₂Py)₂Cl]⁺ (1) and [Ru(κ³-tptz)(κ¹-P-PPh₂Py)₂Cl]⁺ (2), which were isolated as their tetrafluoroborate salts. Under analogous conditions, [Ru(κ³-tpy)Cl₃] gave a neutral complex [Ru(κ³-tpy)(κ¹-PPh₂Py)Cl₂] (3). Upon treatment with an excess of NH₄PF₆ in methanol, 1 and 2 gave [Ru(κ³-tpy)(κ¹-P-PPh₂Py)(κ²-P,N-PPh₂Py)](PF₆)₂ (4) and [Ru(κ³-tptz)(κ¹-P-PPh₂Py)(κ²-P,N-PPh₂Py)](PF₆)₂ (5) containing both monodentate and chelated PPh₂Py. Further, 4 and 5 reacted with an excess of NaCN and CH₃CN to afford [Ru(κ³-tpy)(κ¹-P-PPh₂Py)₂(CN)](PF₆) (6), [Ru(κ³-tpy)(κ¹-P-PPh₂Py)₂(NCCH₃)](PF₆)₂ (7), [Ru(κ³-tptz)(κ¹-P-PPh₂Py)₂(CN)]PF₆ (8) and [Ru(κ³-tptz)(κ¹-P-PPh₂Py)₂(NCCH₃)](PF₆)₂ (9) supporting hemi labile nature of the coordinated PPh₂Py. The complexes have been characterized by elemental analyses, spectral (IR, NMR, electronic absorption, FAB-MS), electrochemical studies and structures of 1, 2 and 3 determined by X-ray single crystal analyses. At higher concentration level (40 μM) the complexes under investigation exhibit inhibitory activity against DNA-Topo II of the filarial parasite S. cervi and 3 catalyses rearrangement of aldoximes to amide under aerobic conditions.     

Reaction of Sulfur and Oxygen-Bridged 8-Quinolinolato Trinuclear Molybdenum Cluster [Mo<Subscript>3</Subscript>OS<Subscript>3</Subscript>(qn)<Subscript>3</Subscript>(H<Subscript>2</Subscript>O)<Subscript>3</Subscript>]<Superscript>+</Superscript> with Acetylene Carboxylic Acids

The reaction of a sulfur and oxygen-bridged 8-quinolinolato trinuclear molybdenum cluster [Mo₃OS₃(qn)₃(H₂O)₃]⁺ (3; Hqn = 8-quinolinol) with equimolar amounts of acetylene carboxylic acid, 4-pentynoic acid, 5-hexynoic acid, acetic acid, and pimelic acid gave clusters having μ-carboxylato groups, [Mo₃OS₃(qn)₃(H₂O)(μ-HC≡CCOO)] (6), [Mo₃OS₃(qn)₃(H₂O)(μ-HC≡C(CH₂)₂COO)] (7), [Mo₃OS₃(qn)₃(H₂O)(μ-HC≡C(CH₂)₃COO)] (8), [Mo₃OS₃(qn)₃(H₂O)(μ-CH₃COO)] (4), and [{Mo₃OS₃(qn)₃(C₂H₅OH)}₂(μ-C₇H₁₀O₄)] (5), respectively. X-ray structural analyses, ¹H NMR, and electronic spectra of these clusters made clear that each of the COO⁻ groups of the reagents bridges two Mo atoms in each cluster and that no adduct formation occurred at the sulfurs in the clusters. The reaction of 3 with a large excess-molar amount (50 times) of acetylene carboxylic acid gave [Mo₃OS(μ₃-SCH=C(COOH)S)(qn)₃(H₂O)(μ-HC≡CCOO)] (9) with two molecules of acetylene carboxylic acid, one acting as a carboxylato bridge and the other in adduct formation, as supported by the electronic and ¹H NMR spectra. The corresponding aqua cluster [Mo₃OS₃(H₂O)₉]⁴⁺ (1), on the contrary, reacts with acetylene carboxylic acid to give adduct [Mo₃OS(μ₃-SCH=C(COOH)S)(H₂O)₉]⁴⁺ (2). Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Carbomolybdate clusters formed by carbonyl insertion into molybdenum-oxygen bonds. Structural investigation of the [RMo4O15X] core (R = ---C9H4O, X = OCH3; R = ---C14H10, X = ---C7H5O2; R = C14H8, X = ---OH)

[C₄H₉)₄N]₂[Mo₂O₇] reacts with a variety of organic species containing α-diketone groups to give tetranuclear complexes of general composition [RMo₄O₁₅X]³⁻. The complexes [(C₄H₉)₄N]₃[(C₉H₄O)Mo₄O₁₅(OCH₃)] (I), [(C₄H₉)₄N]₃[(C₁₄H₁₀)Mo₄O₁₅(C₆H₅CO₂)] (11) and [(C₄H₉)₄N]₃[(C₁₄H₈)Mo₄O₁₅(OH)] (III) were synthesized from the reactions of dimolybdate with ninhydrin, benzil and phenanthraquinone, respectively. Complex II may also be prepared from dimolybdate and benzoin in acetonitrile-methanol solution, from which it co-crystallizes with the binuclear species [(C₄H₉)₄N]₂[Mo₂O₅(C₆H₅C(O)C(O)C₆H₅)₂] · CH₃CN · CH₃OH (IV). Complexes I–III exhibit the tetranuclear core, previously described for the α-glyoxal derivatives [(C₄H₉)₄N]₃[(HCCH)Mo₄O₁₅X], where X = F⁻ or HCO₂⁻. The ligands may be formally described as diketals, formed by insertion of ligand carbonyl subunits into molybdenum-oxygen bonds. The structures I–III differ most dramatically in the identity and coordination mode of the anionic ligand X⁻ which occupies a position opposite the diketal moiety relative to the [Mo₄O₁₁]²⁺ central cage. Thus, I exhibits a doubly bridging methoxy group in this position, while II possesses a benzoate ligand with an unusual μ₃-O,O′coordination mode. Complex III presents a hydroxy-group unsymmetrically bonded to three of the molybdenum centres. The stereochemical consequences of the various coordination modes are discussed. Crystal data: Compound I, monoclinic space group Pc, a = 24.888(2), b = 12.897(3), c = 24.900(3) Å, β = 101.94(2)°, D_calc = 1.28 g cm⁻¹ for Z = 4. Structure solution and refinement based on 8695 reflections with F_o 6σ(F_o) (Mo-K_α, λ = 0.71073 Å) converged at a conventional discrepancy factor of 0.060. Compound II, orthorhombic space group Pbca, a = 20.426(6), b = 26.916(6), c = 32.147(7) Å, V = 17673.2(20) ų, D_calc = 1.33 g cm⁻³ for Z = 8; 5224 reflections, R = 0.076. Compound III, tetragonal space group I4₁/a, a = b = 48.129(6), c = 13.057(2) Å, V = 30246.2(12) ų, D_calc = 1.35 g cm⁻³ for Z = 16; 5554 reflections, R = 0.053. Compound IV, orthorhombic space group Pnca, a = 16.097(4), b = 16.755(4), c = 25.986(7) Å, V = 7008.1(13) ų, Z = 4, D_calc = 1.18 g cm⁻³ ; 2944 reflections, R = 0.061.     

The d metal-sulfosalicylate complexes: Herring-bone, ladder and double-stranded chain frameworks with green luminescences

Assembly of 5-sulfosalicylic acid (H₃L) and d¹⁰ transition metal ions (Cd^II, Ag^I) with the neutral N-donor ligands produces five new complexes: [Cd₂(HL)₂(4,4′-bipy)₃]_n·2nH₂O (1), {[Cd₂(μ₂-HCO₂)₂(4,4′-bipy)₂(H₂O)₄][Cd(HL)₂(4,4′-bipy)(H₂O)₂]}_n (2), {[Cd(4,4′-bipy)(H₂O)₄][HL]·H₂O}_n (3), [Cd(HL)(dpp)₂(H₂O)]_n·4nH₂O (4), {[Ag(4,4′-bipy)][Hhbs]}_n (5) (4,4′-bipy=4,4′-bipyridine, dpp=1,3-di(pyridin-4-yl)propane, H₂hbs=4-hydroxybenzenesulfonic acid, the decarboxylation product of H₃L). Complex 1 adopts a 5-connected 3D bilayer topology. Complex 2 has the herring-bone and ladder chain, which are extended to a 3D network via hydrogen bonding. In 3–4 complexes, 3 is a 3D supermolecular structure formed by polymeric chains and 2D network of HL²⁻, while 4 gives the double-stranded chains. In 5, ladder arrays are stacked with the 2D networks of Hhbs⁻ anions in an –ABAB– sequence. Complexes 1–4 display green luminescences in solid state at room temperature, while emission spectra of 3 and 4 show obvious blue-shifts at low temperature.