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.     

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)}.     

Syntheses and structures of Tetranuclear Cluster complexes of molybdenum [Mo4(μ3-S)2(μ2-S)4 X 2-(PMe3)6] (X = SH,Cl, Br,I, SCN) and [Mo4(μ3-S)2-(μ2-S)4 (dtc)2(PMe3)4] (dtc = diethyldithiocarbamate)

A molybdenum cluster complex [Mo₄(μ₃-S)₂(μ₂-S)₄)(SH)₂(PMe_{3 6}] has been synthesized by the reaction of (NH₄)₂Mo₃S₁₃ with trimethylphosphine. The cluster core is composed of four molybdenum atoms arranged in the rhombus bridged by two capping and four bridging sulfur atoms. Two SH and six tri-methylphosphine ligands are coordinated to the terminal positions. The mean oxidation stares of molybdenum is +3.5 and there are five Mo-Mo bonds consistent with ten metal cluster electrons. The complex has been converted into [Mo₄(μ₃-S)₂(μ₂-S)₄ X ₂(PMe₃)₆] (X=Cl, Br, I, SCN) and [Mo₄μ₃-S₂(μ₂-S)₄ (die)₂(PMe₃)₄] (dtc - diethyldithiocarbamate). In the case of the dtc complex, two terminal trimetlaylphosphine ligands are displaced and dtc ligands are coordinated in chelate fashion. The structures of the SH, Cl, Br, and dtc complexes have been determined by X-ray crystallography. Molecular orbital calculations with DV-Xα method has shown large HOMO-LUMO gaps (1.52-1.74eV) for [Mo₄S₆ X ₂(PH₃)₄] (X= SH, Cl, and Br).     

Structural and Coordinative Variability in Zinc(II), Cadmium(II), and Mercury(II) Complexes of 2‐Pyridineformamide 3‐Hexamethyleneiminylthiosemicarbazone

Sodium in dry methanol reduces 2‐cyanopyridine in the presence of 3‐hexamethyleneiminylthiosemicarbazide and produces 2‐pyridineformamide 3‐hexamethyleneiminylthiosemicarbazone, HAmhexim ( 1 ). Complexes with zinc(II ), cadmium(II ) and mercury(II ) have been prepared and characterized by spectroscopic techniques. In addition, the crystal structures of HAmhexim ( 1 ), [Zn(Amhexim)(OAc)]₂μ·μDMSO ( 2 ), [Cd(HAmhexim)Cl₂]μ·μDMSO ( 7 ), [Cd(Amhexim)₂] ( 8 ), [Cd(HAmhexim)Br₂]μ·μDMSO ( 9 ), [Cd(HAmhexim)I₂]μ·μEtOH ( 10 ), [Hg(HAmhexim)Cl₂]μ·μDMSO ( 11 ), [Hg(Amhexim)Br]₂ ( 13 ), [Hg₃(HAmhexim)(Amhexim)Br₅]μ·μH₂O ( 14 ) and [Hg(Amhexim)I]₂ ( 15 ) have been determined. Coordination of the anionic and neutral thiosemicarbazone ligand occurs through the pyridine nitrogen atom, imine nitrogen atom, and thiolato or thione sulfur atom. In [Zn(Amhexim)(OAc)]₂ one of the bridging acetato ligands has monodentate coordination and the other bridges in a bidentate manner. [Cd(Amhexim)₂] is a 6‐coordinate species while the other cadmium complexes are 5‐coordinate. In [Hg(Amhexim)Br]₂ and [Hg(Amhexim)I]₂ the thiolato sulfur atoms act as bridges between the Hg atoms to form dimeric compounds and [Hg₃(HAmhexim)(Amhexim)Br₅]μ·μH₂O is a trinuclear complex with three different centers — two metallic centers have a 5‐coordination and the another one has 4‐coordination. In addition, [Hg(HAmhexim)Cl₂]μ·μDMSO and [Hg₃(HAmhexim)(Amhexim)Br₅]μ·μH₂O shown a supramolecular one‐dimensional hydrogen‐bonded self‐assembling.     

Thiochloroanionen von Molybdän(IV). Die Kristallstruktur von (NEt4)3[Mo3(μ3-S)(μ-S2)3Cl6]Cl · CH2Cl2 Kristallstruktur,EPR-Spektrum und magnetische Eigenschaften von (NEt4)2[Mo2(μ-S2)(μ-Cl)2Cl6]

Thiochloro Anions of Molybdenum (IV). Crystal Structure of (NEt₄)₃[Mo₃(μ₃-S)(μ-S₂)₃Cl₆]Cl μ CH₂Cl₂. Crystal Structure, Magnetic Properties, and EPR-Spectrum of (NEt₄)₂ [Mo₂(μ-S₂)(μ-Cl)₂Cl₆] From molybdenum pentachloride and tetraethylammonium hydrogensulfide in CH₂Cl₂ an insoluble product of composition (NEt₄)₂[Mo₂S₃Cl₉] was obtained along with a brown solution, from which (NEt₄)₂[Mo₂(S₂)Cl₈] was crystallized. The insoluble product and NEt₄Cl react in CH₂Cl₂ to yield, among others, (NEt₄)₃[Mo₃(S)(S₂)₃Cl₆]Cl · CH₂Cl₂. The latter crystallizes in the orthorhombic space group Pnma, a = 2495.8, b = 1501.2, c = 1295.6 pm, Z = 4. According to the crystal structure determination (3070 observed reflexions, R = 0.049) the [Mo₃(S)(S₂)₃Cl₆]^2? ion consists of an Mo₃ triangle with Mo? Mo bonds, each side of the triangle is bridged by disulfido groups and one sulfur atom is capped over the Mo₃ triangle; the single chloride ion is looseley associated to three S atoms. (NEt₄)₂[Mo₂(S₂)Cl₈] also crystallizes in the space group Pnma, a = 1425.6, b = 1129.9, c = 2004.7 pm, Z = 4; structure determination with 1703 observed reflexions, R = 0.061. In the [Mo₂(S₂)Cl₈]^2? ion the Mo atoms are bridged via one disulfido group and two chlorine atoms. There is a Mo? Mo bond, but according to the magnetic properties and the EPR spectrum each Mo atom still possesses one unpaired electron.     

Stepwise substitution of oxo-centered,trinuclear chromium(III) carboxylates with Schiff base

Oxo-centered, trinuclear, mixed-ligand complexes of chromium(III) have been synthesized by stepwise substitutions of acetate ions of [Cr₃O(OOCMe)₄(OOCR)₃] · 3MeOH (1) and the isolated products of the type [Cr₃O(OOCMe)₂ (SB)(OOCR)₃]PF₆ · 3MeOH (2), [Cr₃O(OOCMe)(SB)₂(OOCR)₃]PF₆ · 3MeOH (3) and [Cr₃O(SB)₃(OOCR)₃]PF₆ · 3MeOH (4) [where R = C₁₃H₂₇ and HSB = C₆H₄(OH)CHNC₆H₄Cl] have been characterized by a full battery of complementary physico–chemical methods including spectral (infrared, electronic, FAB mass and powder XRD) studies, elemental and thermogravimetric analyses, molar conductance and magnetic susceptibility measurements. The infrared spectra suggest the bridging nature of both carboxylate and Schiff base anions along with ν _asym(Cr₃O) vibrations in the complexes. The trinuclear nature of the complexes has been assessed from FAB mass data. Electronic spectra and magnetic moment values were consistent with chromium(III) ion present in an octahedral environment which was supported by their powder X-ray diffraction data. Cyclic voltammetric data of complex (4) indicate a reversible oxidation wave and an irreversible reduction wave in the range − 1.2–0.6 V. The decomposition pathway of all the complexes has been discussed on the basis of thermogravimetric analysis data. Conductance data indicate the monocationic nature of the complexes and their plausible structure has been established on the basis of above physico–chemical studies.     

Synthesis and structure of the cluster μ3-sulfido-μ-–(diethylphosphorodithioato-S,S'-)-allylthioureocyclo-tris-[ (μ-sulfido)-χ-(diethylphosphorodithioato-S,S')-molybdenum(IV)], Mo3S4(C4H10O2S2P)4(C4H8N2S)

Title compound, M_r =1273.16, was synthesized by a substitution reaction and its crystal is triclinic belonging to space group P1 with cell parameters: a =13.944(2), b =14.143(7), c =14.233(3) Å, α =77.35(3)°, β =69.94(2)°, γ =63.50(3)°, V=2351(1) ų, Z=2, D_c =1.799g cm^?2. Room temperature, graphite-filtered Mo K_α radiation (λ =0.71073Å) was used for data collection. μ =14.988 cm^?1, F(000) =1280, R=0.051 for 7025 observed reflections. The crystal consists of decrete cluster molecules containing a cluster core [Mo₂(μ₃-S)]¹⁰⁺ with three μ-S, one μ-dtp(dtp =[S₂P(OC₂H₅)]^2-), three χ-dtp and one allylthioureo to form a local six-coordinated sphere around each Mo atom. The bonds of cluster skeleton [Mo₃(μ₃-S)(μ-S)₃]⁴⁺, Mo? Mo 2.744～2.766, Mo—(μ₂-S) 2.340～2.342 and Mo—(μ-S)2.272～2.296 Å, are comparable with those found in the related analogues.     

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.     

Molybdän‐ und Wolfram‐Komplexe mit MNS‐Sequenzen. Die Kristallstrukturen von [MoCl3(N3S2)(1,4‐Dioxan)2] und [Mo2Cl2(μ‐NSN)2(μ‐O)(NCMe3)(OCMe3)2]2

Molybdenum and Tungsten Complexes with MNS Sequences. Crystal Structures of [MoCl₃(N₃S₂)(1,4‐dioxane)₂] and [Mo₂Cl₂(μ‐NSN)₂(μ‐O)(NCMe₃)(OCMe₃)₂]₂ The cyclo‐thiazeno complexes [Cl₃MNSNSN]₂ of molybdenum and tungsten react with 1,4‐dioxane in dichloromethane suspension to give the binuclear donor‐acceptor complexes [μ‐(1,4‐dioxane){MCl₃(N₃S₂)}₂] which are characterized by IR spectroscopy. With excess 1,4‐dioxane the molybdenum compound forms the complex [MoCl₃(N₃S₂)(1,4‐dioxane)₂] in which, according to the crystal structure determination, one of the dioxane molecules coordinates at the molybdenum atom, the other one at one of the sulfur atoms of the cyclo‐thiazeno ring. The μ‐(NSN^2–) complex [Mo₂Cl₂(μ‐NSN)₂(μ‐O)(NCMe₃)(OCMe₃)₂]₂ has been obtained by the reaction of [MoN(OCMe₃)₃] with trithiazyle chloride in carbontetrachloride solution. According to the crystal structure determination this compound forms centrosymmetric dimeric molecules via two of the nitrogen atoms of two of the μ‐(NSN) groups to give a Mo₂N₂ fourmembered ring. [MoCl₃(N₃S₂)(1,4‐dioxane)₂]: Space group P2₁/c, Z = 4, lattice dimensions at –70 °C: a = 1522.9(2); b = 990.3(1); c = 1161.7(1) pm; β = 106.31(1)°, R₁ = 0.0317. [Mo₂Cl₂(μ‐NSN)₂(μ‐O)(NCMe₃)(OCMe₃)₂]₂ · 4 CCl₄: Space group P2₁/c, Z = 2, lattice dimensions at –83 °C: a = 1216.7(1); b = 2193.1(2); c = 1321.8(1) pm; β = 98.23(1)°; R₁ = 0.0507.     

Tuning the sulfur-heterometal interaction in organolead(IV) complexes of [Pt2(μ-S)2(PPh3)4]

Reactions of [Pt₂(μ-S)₂(PPh₃)₄] with Ph₃PbCl, Ph₂PbI₂, Ph₂PbBr₂ and Me₃PbOAc result in the formation of bright yellow to orange solutions containing the cations [Pt₂(μ-S)₂(PPh₃)₄PbR₃]⁺ (R₃ = Ph₃, Ph₂I, Ph₂Br, Me₃) isolated as PF₆⁻ or BPh₄⁻ salts. In the case of the Me₃Pb and Et₃Pb systems, a prolonged reaction time results in formation of the alkylated species [Pt₂(μ-S)(μ-SR)(PPh₃)₄]⁺ (R = Me, Et). X-ray structure determinations on [Pt₂(μ-S)₂(PPh₃)₄PbMe₃]PF₆ and [Pt₂(μ-S)₂(PPh₃)₄PbPh₂I]PF₆ have been carried out, revealing different coordination modes. In the Me₃Pb complex, the (four-coordinate) lead atom binds to a single sulfur atom, while in the Ph₂PbI adduct coordination of both sulfurs results in a five-coordinate lead centre. These differences are related to the electron density on the lead centre, and indicate that the interaction of the heterometal centre with the {Pt₂S₂} metalloligand core can be tuned by variation of the heteroatom substituents. The species [Pt₂(μ-S)₂(PPh₃)₄PbR₃]⁺ display differing fragmentation pathways in their ESI mass spectra, following initial loss of PPh₃ in all cases; for R = Ph, loss of PbPh₂ occurs, yielding [Pt₂(μ-S)₂(PPh₃)₃Ph]⁺, while for R = Me, reductive elimination of ethane gives [Pt₂(μ-S)₂(PPh₃)₃PbMe]⁺, which is followed by loss of CH₄.     

Coordination of Phenylsulfinate PhSO2— to Mo3MS44+ Clusters (M = Ni,Pd)

Reaction of heterometal cuboidal clusters [Mo₃(MCl)S₄(H₂O)₉]³⁺ (M = Ni, Pd) with PhSO₂Na in aqueous HCl leads to the substitution at Ni or Pd to give the [Mo₃(M(PhSO₂))(H₂O)_9—xCl_x]^(3—x)+species, isolated as supramolecular adducts with cucurbituril (Cuc) [Mo₃(Ni(PhSO₂))S₄Cl_1.17(H₂O)_7.83][Mo₃(Ni(PhSO₂))S₄Cl_2.22(H₂O)_6.78]Cl_2.61 · Cuc · 15H₂O ( 1 ) and [Mo₃(Pd(PhSO₂))S₄Cl_1.12(H₂O)_7.88][Mo₃(Pd(PhSO₂))S₄Cl_2.29(H₂O)_6.71]Cl_2.59 · Cuc · 11H₂O ( 2 ), respectively. Crystal structure of 1 and 2 was determined, revealing that the PhSO₂ is coordinated via its sulfur atom (Ni — S 2.182 Å, Pd — S 2.305 Å). The structure of these isostructural compounds is built from triple aggregates {(cluster)(Cuc)(cluster)} united into zigzag chains via hydrogen bonds between coordinated PhSO₂ and H₂O ligands.     

The Electron Transfer Series [MoIII(bpy)3]n (n=3+, 2+, 1+, 0, 1−), and the Dinuclear Species [{MoIIICl(Mebpy)2}2(μ2‐O)]Cl2 and [{MoIV(tpy.)2}2(μ2‐MoO4)](PF6)2⋅4 MeCN

The electronic structures of the five members of the electron transfer series [Mo(bpy)₃]ⁿ (n=3+, 2+, 1+, 0, 1?) are determined through a combination of techniques: electro‐ and magnetochemistry, UV/Vis and EPR spectroscopies, and X‐ray crystallography. The mono‐ and dication are prepared and isolated as PF₆ salts for the first time. It is shown that all species contain a central Mo^III ion (4d³). The successive one‐electron reductions/oxidations within the series are all ligand‐based, involving neutral (bpy⁰), the π‐radical anion (bpy^.)^1?, and the diamagnetic dianion (bpy^2?)^2?: [Mo^III(bpy⁰)₃]³⁺ (S=3/2), [Mo^III(bpy^.)(bpy⁰)₂]²⁺ (S=1), [Mo^III(bpy^.)₂(bpy⁰)]¹⁺ (S=1/2), [Mo^III(bpy^.)₃] (S=0), and [Mo^III(bpy^.)₂(bpy^2?)]^1? (S=1/2). The previously described diamagnetic dication “[Mo^II(bpy⁰)₃](BF₄)₂” is proposed to be a diamagnetic dinuclear species [{Mo(bpy)₃}₂(μ₂‐O)](BF₄)₄. Two new polynuclear complexes are prepared and structurally characterized: [{Mo^IIICl(^Mebpy⁰)₂}₂(μ₂‐O)]Cl₂ and [{Mo^IV(tpy^.)₂}₂(μ₂‐Mo^VIO₄)](PF₆)₂?4 MeCN.     

Preparation and properties of some cationic binuclear platinum(I) complexes

Reaction of [Pt₂Cl₂(μ-dppm)₂] with ligands, L, in the presence of [PF₆^- gave stable cationic diplatinum(I) complexes [Pt₂L₂(μ-dppm)₂][PF₆]₂ where L = PMe₂Ph, PMePh₂, PPh₃, NH₃, C₅H₅N. Reaction of [Pt₂(NH₃)₂(μ-dppm)₂][PF₆]₂ with CO gave [Pt₂(CO)₂(μ-dppm)₂][PF₆]₂ and an unsymmetrical complex [Pt₂(CO)(C₅H₅N)(μ-dppm)₂][PF₆]₂ was also prepared. The compounds were characterized by vibrational and ¹H and ³¹P NMR spectroscopy and the presence of direct platinumplatinum bonds is indicated.     

系列三核钼硫簇合物的合成、结构表征和性质研究

系统地报道了9个三核钼硫簇合物的合成和结构表征. 晶体结构分析表明, 其中化合物1和6具有[Mo₃(μ₃-S)(μ-S)₃]簇芯, 化合物2和3具有不对称的簇芯[Mo₃(μ₃-S)(μ-O)(μ-S)₂], 化合物4, 5, 7和8具有少见的[Mo₃(μ₃-O)(μ-S)₃]簇芯, 而化合物9则具有[Mo₃(μ₃-S)(μ-S₂)₃]簇芯. 这一系列不同的簇芯以及桥配体和“松散”配位的端配体造成了不同的堆积结构. 讨论了前三种簇芯的电子结构, 并根据它们的立体构型和电子结构对某些重要的谱学表征结果做了合理的诠释. 测定了化合物4的变温电导率, 表明其具有半导体导电性能.     

Studies on reactivities of molybdenum clusters — The additive reaction of SbCl3 to trimolybdenum clusters with loose coordination sites and the crystal structure of the reaction product

The additive reaction of SbCl₃ to trimolybdenum clusters with loose coordination sites, Mo₃(μ₃-S) (μ-S)₃ [S₂P (OEt)₂]₄ · L' (1 L' ? H₂O; 2, L' ? C₃H₃ON), in a C₂H₅OH-HCl medium yields complexes {Mo₃ (μ₃-S) [(μ-S)₃ · SbCl₃] [S₂P (OEt)₂]₄ · (C₂H₅OH)} (C₂H₅OH) (3) and {Mo₃ (μ₃-S) [(μ-S)₃ · SbCl₃] [S₂P (OEt)₂]₃ [SXP (OEt)₂] · (C₃H₃ON)} (X ? S,O) (4), respectively. The crystal and molecular structures of these two compounds have been determined by single crystal X-ray crystallography: crystal 3 belongs to the monoclinic system, P2₁,/n, while crystal 4 belongs to the triclinic system, P 1, The intensity data were collected on an Enraf-Nonius CAD-4 diffractometer with graphite-monochromatized MoKα radiation by using the ω-2θ technique. The structures were solved by the Patterson method as well as direct methods and refined by full matrix least-squares method. Final R values were 0.078 for crystal 3 and 0.068 for crystal 4, respectively. The result of the structure determination showed that the two molecular structures are practically formed by connecting a trimolybdenum clusters with loose coordination sites, {Mo₂(μ₃-S)- (μ-S)₃[S₂P(OEt)₂]₄ · L (L ? C₂H₅OH, C₃H₃ON), with a SbCl₃ molecule through three (μ-S) atoms to form the {Mo SbS₄} core of a cubane-like type. There are relatively weak coordination bonds between the Sb and the three (μ-S) atoms, while no bonding interaction between the Sb and the three Mo atoms is found. In the additive compounds the structural character of the trimolybdenum clusters with loose coordination sites has significantly been changed. In addition, 3 still has the reactivity for the loosely coordinated EtOH to be replaced by an oxazole ring to form crystal 4. However, the three (μ-S) atoms may be regarded as triple bridging S atoms each connecting two Mo atoms and a Sb atom. The information obtained serves as an evidence that the tetranuclear clusters might be formed by a [3 + 1] reaction mode.     

[Mo4O4(μ-S)4(μ-OH)2(μ-H2O)(H2O)2(pba)]2−: An Original Coordination Mode for the Ligand 1,3-Propylenebis(Oxamate)

The novel polyoxothioanion [Mo₄S₄O₄(OH)₂(OH₂)₃pba]^2? where pba^4? ligand is the 1,3-propylenebis(oxamate), was prepared by reacting Mo₁₂S₁₂O₁₂(OH)₁₂(OH₂)₆ ring with [Cu-pba]^2? in aqueous medium. NaK[Mo₄O₄(μ-S)₄(μ-OH)₂(μ-H₂O)(H₂O)₂(pba)] ·7H₂O was isolated in the solid state and fully characterized by X-ray diffraction study (tetragonal, P4(2)/m [a=20.4962(4) Å; b=20.4962(4) Å; c=14.7013(5) Å). The molecular structure consists of an arc cycle shape tetranuclear enchainment {Mo₄S₄O₄(OH)₂ (OH₂)₃} closed by a pba^4? ligand. The 3-D packing, resulting from the connection between K⁺ and Na⁺ and the coordination complex {Mo₄-pba]^2? is described. The ¹H-NMR characterization of the complex in aqueous solution is given. The ¹H-NMR spectrum exhibits four signals assigned to four enantiotopic protons of the alkyl chain of the pba^4? ligand and is in agreement with crystal structure of the complex [Mo₄-pba]^2?. The compound was also characterized by infrared spectroscopy.     

Cuboidal oxalate cluster complexes with the Mo<Subscript>3</Subscript>CuQ<Subscript>4</Subscript><Superscript>5+</Superscript> cluster core (Q = S or Se): synthesis,structure, and electrochemical properties

The reactions of the [Mo₃(μ₃-Q)(μ₂-Q)₃(H₂O)₃(C₂O₄)₃]²⁻ complex (Q = S or Se) with CuX salts (X = Cl, Br, I, or SCN) in water produce the cuboidal heterometallic clusters [Mo₃(CuX)(μ₃-Q)₄(H₂O)₃(C₂O₄)₃]²⁻, which were isolated as the potassium and tetraphenylphosphonium salts. Two new compounds, K₂[Mo₃(CuI)(μ₃-S)₄(H₂O)₃(C₂O₄)₃]·6H₂O and (PPh₄)₂[Mo₃(CuBr)(μ₃-S)₄(H₂O)₃(C₂O₄)₃]·7H₂O, were structurally characterized. All compounds were characterized by elemental analysis and IR spectroscopy. The K₂[Mo₃(CuI)(μ₃-Se)₄(H₂O)₃(C₂O₄)₃] compound was characterized by the ⁷⁷Se NMR spectrum; the (PPh₄)₂[Mo₃(CuI)(μ₃-S)₄(H₂O)₃(C₂O₄)₃], (PPh₄)₂[Mo₃(CuI)(μ₃-Se)₄(H₂O)₃(C₂O₄)₃] and K₂[Mo₃(CuSCN)(μ₃-S)₄(H₂O)₃(C₂O₄)₃]·7H₂O compounds, by electrospray mass spectra. Dedicated to Academician G. A. Abakumov on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1639–1644, September, 2007.     

Synthesen und Strukturen neuer amido- und imidoverbrückter Cobaltcluster: [Li(THF)2]3[Co3(μ2-NHMes)3Cl6] (1), [Li(DME)3]2[Co18(μ4-NPh)3(μ3-NPh)12Cl3] (2), [Li(DME)3]2[Co6(μ4-NPh)(μ2-NPh)6(PPh2Et)2] (3) und [Li(THF)4][Co8(μ3-NPh)6(μ2-NPh)3(PPh3)2] (4)

Syntheses and Crystal Structures of new Amido- und Imidobridged Cobalt Clusters: [Li(THF)₂]₃[Co₃(μ₂-NHMes)₃Cl₆] (1), [Li(DME)₃]₂[Co₁₈(μ₄-NPh)₃(μ₃-NPh)₁₂Cl₃] (2), [Li(DME)₃]₂[Co₆(μ₄-NPh)(μ₂-NPh)₆(PPh₂Et)₂] (3), and [Li(THF)₄][Co₈(μ₃-NPh)₆(μ₂-NPh)₃(PPh₃)₂] (4) The reactions of cobalt(II)-chloride with the lithium-amides LiNHMes and Li₂NPh leads to an amido-bridged multinuclear complex [Li(THF)₂]₃[Co₃(μ₂-NHMes)₃Cl₆] ( 1 ) as well as to the imido-bridged cobalt cluster [Li(DME)₃]₂[Co₁₈(μ₄-NPh)₃(μ₃-NPh)₁₂Cl₃] ( 2 ). In the presence of tertiary phosphines two imido-bridged cobalt clusters [Li(DME)₃]₂[Co₆(μ₄-NPh)(μ₂-NPh)₆(PPh₂Et)₂] ( 3 ) and [Li(THF)₄][Co₈(μ₃-NPh)₆(μ₂-NPh)₃(PPh₃)₂] ( 4 ) result. The structures of 1 – 4 were characterized by X-ray single crystal structure analysis.     

Mononuclear and binuclear lanthanide(III) complexes: syntheses,structural, photophysical and thermal properties

Six new Ln(III) complexes viz., [Gd(tptz)(SCN)₃(CH₃OH)₂OH₂]·CH₃OH (1), [Eu(tptz)(SCN)₃(CH₃OH)₂OH₂]·CH₃OH (2), [Tb(tptz)(SCN)₃(OH₂)₃]₄ (3), [Gd(tptz)(OBz)₂(μ-OBz)OH₂]₂·2H₂O (4), [OH₂(OBz)₂(tptz)Eu₁(μ-OBz)₂Eu₂(tptz)(OBz)₂OH₂]·CH₃OH·7H₂O (5), and {[Tb₁(tptz)(OBz)₂(μ-OBz)]₂·[Tb₂(tptz)(OBz)₃CH₃OH]₂}·2CH₃OH·4H₂O (6) (Ln = Gd, Eu, Tb; tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine; BzONa = sodium benzoate), have been synthesized and characterized by physicochemical methods including single-crystal X-ray crystallography. The X-ray studies demonstrate that 1–3 are mononuclear, whereas 4–6 are binuclear. The photophysical properties of 1–6 have been studied with ultraviolet absorption and emission spectral studies. Their thermal properties have been studied by thermogravimetric (TG) and derivative thermogravimetric analysis (DTG), demonstrating that the final product after decomposition was Ln₂O₃ for all these complexes.     

Synthesis and Crystal Structure of Cucurbit[6]uril Adduct of Hydrogen-bonded Cluster Complex [Mo3(μ3-Se)(μ2-O)3(H2O)6Cl3]+

Reaction of [MoOCl₅]²⁻ with in situ generated H₂Se under hydrothermal conditions (4M HCl, 140 °C) leads to reduction of Mo(V) to Mo(IV) with the formation of a triangular cluster Mo₃(μ₃-Se)(μ-O)₃⁴⁺ in high yield. It is present in HCl solutions as aqua chlorocomplex [Mo₃(μ₃-Se)(μ-O)₃(H₂O)₆Cl₃]⁺ which was isolated and structurally characterized as supramolecular adduct with cucurbit[6]uril (CB[6]), {[Mo₃(μ₃-Se)(μ-O)₃(H₂O)₆Cl₃]₂CB[6]}Cl₂·15H₂O. Dedicated to Professor Dieter Fenske on the Occasion of his 65th Birthday