Lanthanide clusters with internal Ln: fragmentation and the formation of dimers with bridging Se(2-) and Se2(2-) ligands

Reactions of "LnI(x)(SePh)(3-x)" (Ln = Dy, Ho) with elemental S/Se give (THF)14Ln10S6(Se2)6I6. The compounds are composed of a Ln6S6 double cubane core, with two twisted "Ln2(SeSe)3" units condensed onto opposing rectangular sides of the Ln6S6 fragment. This deposition of Ln2Se6 totally encapsulates the two central Ln's with chalcogen atoms (four S and four Se atoms), excluding neutral THF donors or iodides from the two primary coordination spheres. Reactions of Ln(10) clusters with a stronger Lewis base result in fragmentation and, in the case of Ln = Er, the isolation of (py)6Er2(Se2)(S0.8Se0.2)I2, with two Ln(III) ions spanned by E2- and (EE)2- ligands. The related homochalcogen dimers (py)6Ln2(Se2)(Se)Br2 (Ln = Ho, Yb) were prepared to establish that such molecules could be prepared rationally, and to confirm the isolability of E2- ligands coordinated to only two sterically unconstrained Ln ions.     

Coordination of cyclo-octasulfur and cyclo-heptaselenium to dinuclear rhenium(I) systems

By substitution reactions of the coordinated THF ligands of Re(2)(mu-X)(2)(CO)(6)(THF)(2) by elemental chalcogens (S(8) and red selenium), the complexes Re(2)(mu-X)(2)(CO)(6)(S(8)) (X = Br, 1; I, 2), and Re(2)(mu-X)(2)(CO)(6)(Se(7)), (X = I, 3; Br, 4) have been prepared. Binuclear compound 3 was crystallographically established to be a coordination compound of cyclo-heptaselenium, two adjacent selenium atoms of the Se(7) ligand [Se-Se distance, 2.558(3) A] being bonded to rhenium(I), at an average Re-Se distance of 2.586(3) A, and the nonbonding Re.Re distance being 4.077(3) A. Spectroscopic evidence of the existence of these chalcogen complexes in solution is reported. The Re(2)(mu-X)(2)(CO)(6)(S(8)) complexes undergo S(8) displacement by THF, while the coordinated Se(7) moiety is less readily displaced from 3.     

Heterometallic chalcogenido clusters containing lanthanides and main group metals: emissive precursors to ternary solid-state compounds

Heterometallic clusters containing lanthanides and the group 12 metals can be isolated as crystalline compounds in high yields. These products [(py)8Ln4M2Se6(SePh)4 (Ln = Er, Yb, Lu; M = Cd, Hg)] adopt a double cubane structure with the covalent M occupying an opposing pair of external metal sites. Both Er/M compounds are strongly emissive materials, with emission lifetimes of 1.41 ms (Er/Cd) and 0.71 ms (Er/Hg) and with the Er/Cd radiative quantum efficiency twice that of the Er/Hg compound. Thermal decomposition of the Er/Cd and Yb/Cd compounds at 650 degrees C give the ternary solid-state materials CdLn2Se4.     

Synthesis and Characterization of Novel Lanthanocene Complexes with Dichalcogenolate o-Carboranyl Ligands

ＩｎｔｒｏｄｕｃｔｉｏｎＵｐｔｏｄａｔｅｃｏｎｓｉｄｅｒａｂｌｅａｔｔｅｎｔｉｏｎｈａｓｂｅｅｎｄｅｖｏｔｅｄｔｏｔｈｅｍｅｔａｌｃｏｍｐｌｅｘｅｓｗｉｔｈｃｈａｌｃｏｇｅｎｏｌａｔｅｌｉｇａｎｄｓ .1,2Ｒｅｃｅｎｔｌｙｔｒａｎｓｉｔｉｏｎｍｅｔａｌｃｏｍｐｌｅｘｅｓｃｏｎｔａｉｎｉｎｇａｃｈｅｌａｔｉｎｇ1,2 ｄｉｃａｒｂａ ｃｌｏｓｏ ｄｏｄｅｃａｂａｒａｎｅ 1,2 ｄｉｃｈａｌｃｏｇｅｎｏｌａｔｅｌｉｇ ａｎｄｓ3 10 ｈａｖｅａｔｔｒａｃｔｅｄａｇｒｅａｔｄｅａｌｏｆｉｎｔｅｒｅｓｔｄｕｅｔｏｔ…     

Selenium as a structural surrogate of sulfur: template-assisted assembly of five types of tungsten-iron-sulfur/selenium clusters and the structural fate of chalcogenide reactants

Syntheses of five types of tungsten-iron-sulfur/selenium clusters, namely, incomplete cubanes, single cubanes, edge-bridged double cubanes (EBDCs), P(N)-type clusters, and double-cuboidal clusters, have been devised using the concept of template-assisted assembly. The template reactant is six-coordinate [(Tp*)W(VI)S(3)](1-) [Tp* = tris(3,5-dimethylpyrazolyl)hydroborate(1-)], which in the assembly systems organizes Fe(2+/3+) and sulfide/selenide into cuboidal [(Tp*)WFe(2)S(3)] or cubane [(Tp*)WFe(3)S(3)Q] (Q = S, Se) units. With appropriate terminal iron ligation, these units are capable of independent existence or may be transformed into higher-nuclearity species. Selenide is used as a surrogate for sulfide in cluster assembly in order to determine by X-ray structures the position occupied by an external chalcogenide nucleophile or an internal chalcogenide atom in the product clusters. Specific incorporation of selenide is demonstrated by the formation of [WFe(3)S(3)Se](2+/3+) cubane cores. Reductive dimerization of the cubane leads to the EBDC core [W(2)Fe(6)S(6)Se(2)](2+) containing μ(4)-Se sites. Reaction of these species with HSe(-) affords the P(N)-type cores [W(2)Fe(6)S(6)Se(3)](1+), in which selenide occupies μ(6)-Se and μ(2)-Se sites. The reaction of [(Tp*)WS(3)](1-), FeCl(2), and Na(2)Se yields the double-cuboidal [W(2)Fe(4)S(6)Se(3)](2+/0) core with μ(2)-Se and μ(4)-Se bridges. It is highly probable that in analogous sulfide-only assembly systems, external and internal sulfide reactants occupy corresponding positions in the cluster products. The results further demonstrate the viability of template-assisted cluster synthesis inasmuch as the reduced (Tp*)WS(3) unit is present in all of the clusters. Structures, zero-field M?ssbauer data, and redox potentials are presented for each cluster type.     

Precursors to clusters with the topology of the P(N) cluster of nitrogenase: edge-bridged double cubane clusters [(Tp)2Mo2Fe6S8L4]z: synthesis, structures, and electron transfer series

Members of the cluster set [(Tp)2Mo2Fe6S8L4]z contain the core unit M2Fe6(mu3-S)6(mu4-S)2 in which two MoFe3S4 cubanes are coupled by two Fe-(mu4-S) interactions to form a centrosymmetric edge-bridged double cubane cluster. Some of these clusters are synthetic precursors to [(Tp)2Mo2Fe6S9L2]3-, which possess the same core topology as the P(N) cluster of nitrogenase. In this work, the existence of a three-member electron-transfer series of single cubanes [(Tp)MoFe3S4L3](z) (z = 3-, 2-, 1-) and a four-member series of double cubanes [(Tp)2Mo2Fe6S8L4]z (z = 4-, 3-, 2-, 1-) with L = F-, Cl-, N3, PhS- is demonstrated by electrochemical methods, cluster synthesis, and X-ray structure determinations. The potential of the [4-/3-] couple is extremely low (<-1.5 V vs SCE in acetonitrile) such that the 4- state cannot be maintained in solution under normal anaerobic conditions. The chloride double cubane redox series was examined in detail. The members [(Tp)2Mo2Fe6S8Cl4]4-,3-,2- were isolated and structurally characterized. The redox series includes the reversible steps [4-/3-] and [3-/2-]. Under oxidizing conditions, [(Tp)2Mo2Fe6S8Cl4]2- cleaves with the formation of single cubane [(Tp)MoFe3S4Cl3]1-. The quasireversible [2-/1-] couple is observed at more positive potentials than those of the single cubane redox step. Structure comparison of nine double cubanes suggests that significant dimensional changes pursuant to redox reactions are mainly confined to the Fe2(mu4-S)2 bridge rhomb. The synthesis and structure of [(Tp)2Mo2Fe6S9F2.H2O]3-, a new topological analogue of the P(N) cluster of nitrogenase, is described. (Tp = hydrotris(pyrazolyl)borate(1-)).     

U(IV) chalcogenolates synthesized via oxidation of uranium metal by dichalcogenides

Treatment of uranium metal with dichalcogenides in the presence of a catalytic amount of iodine in pyridine affords molecular U(IV) chalcogenolates that do not require stabilizing ancillary ligands. Oxidation of U(0) by PhEEPh yields monomeric seven-coordinate U(EPh)4(py)3 (E = S(1), Se(2)). The dimeric eight-coordinate complexes [U(EPh)2(mu2-EPh)2(CH3CN)2]2 (E = S(3), Se(4)) are obtained by crystallization from solutions of 1 and 2 dissolved in acetonitrile. Oxidation of U(0) by pySSpy and crystallization from thf yields nine-coordinate U(Spy)4(thf) (5). Incorporation of elemental selenium into the oxidation of U(0) by PhSeSePh results in the isolation of [U(py)2(SePh)(mu3-Se)(mu2-SePh)]4.4py (6), a tetrameric cluster in which each U(IV) ion is eight-coordinate and the U4Se4 core forms a distorted cube. The compounds were analyzed spectroscopically and the single-crystal X-ray structures of 1 and 3-6 were determined. The isolation of 1-6 represents six new examples of actinide chalcogenolates and allows insight into the nature of "hard" actinide ion-"soft" chalcogen donor interactions.     

Chalcogen-rich lanthanide clusters with fluorinated thiolate ligands

Mixtures of Ln(SC(6)F(5))(3) and Ln(EPh)(3) (E = S, Se) react with elemental E to give chalcogen-rich clusters with fluorinated thiolate ancillary ligands. The structures of both (THF)(6)Yb(4)S(SS)(4)(SC(6)F(5))(2) and (THF)(6)Yb(4)Se(SeSe)(4)(SC(6)F(5))(2) have been established by low-temperature single-crystal X-ray diffraction. Both compounds contain a square array of Yb(III) ions connected by a central mu(4)-E(2-) ligand. The edges of the square Yb(4) array are bridged by four mu(2)(EE) ligands, and two terminal SC(6)F(5) are on the same side of the Ln(4) plane that is capped by the mu(4)-E(2-) ion. Redox inactive (THF)(6)Tm(4)Se(SeSe)(4)(SC(6)F(5))(2) was also prepared to establish the extension of this chemistry to the redox inactive Ln. These clusters are soluble in toluene.     

Molybdenum-iron-sulfur clusters of nuclearities eight and sixteen, including a topological analogue of the P-cluster of nitrogenase

Transformations of the edge-bridged double cubane cluster [(Cl4cat)2(Et3P)2Mo2Fe6S8(PEt3)4] (1) under reducing conditions have been investigated as synthetic approaches to the clusters of nitrogenase. Cluster 1 is a versatile precursor to different Mo-Fe-S cluster types. The reaction system 1/K(C14H10) in THF yields the reduced cluster [(Cl4cat)2(Et3P)2Mo2Fe6S8(PEt3)4]1- (2), which as its crystalline Et4N+ salt retains the edge-bridged structure of 1. X-ray structural and M?ssbauer spectroscopic results indicate an unsymmetrical electron distribution with localized [MoFe3S4]2+,1+ cubane-type units. The system 1/2K(C14H10)/2HS- in THF/acetonitrile affords [(Cl4cat)4(Et3P)4Mo4Fe12S20K3(DMF)]5- (3), whose structure was determined as the Ph3PMe+ salt. The cluster consists of two isostructural Mo2Fe6S9 fragments connected by two mu 2-S bridges. Three potassium ions are bound between the two fragments. In each fragment, the iron atoms are present in tetrahedral FeS4 and the molybdenum atoms in octahedral MoO2PS3 coordination units, and two MoFe3(mu 3-S)3 cuboidal units are bridged by a common mu 6-S atom. The fragments have idealized mirror symmetry and are isostructural with two of the fragments present in the previously reported high-nuclearity cluster [(Cl4cat)6(Et3P)6Mo6Fe20S30]8- (4) (Osterloh, F.; Sanakis, Y.; Staples, R. J.; Münck, E.; Holm, R. H. Angew. Chem., Int. Ed. Engl. 1999, 38, 2066). On the basis of overall shape, atom connectivities, and metric features, the Mo2Fe6S9 fragment is a topological analogue of the P-cluster of nitrogenase in the PN (reduced) state. A third cluster type, formed as a minor byproduct in the reaction system leading to 2, was crystallographically identified as [(Cl4cat)2(Et3P)2Mo2Fe6S8(PEt3)4]4-, whose core is made up of two MoFe3(mu 3-S)3 cuboidal units bridged by two mu 2-S atoms and connected by a direct Fe-Fe bond. Full structural details and the redox properties of 2 and 3 are reported.     

Chalcogen-rich lanthanide clusters: cluster reactivity and the influence of ancillary ligands on structure.

Ytterbium metal reacts with PhEEPh (E = S, Se, Te) and elemental Se in pyridine to give (pyridine)(8)Yb(4)(SeSe)(2)(Se)(2)(mu(2)-SPh)(2)(SPh)(2), (py)(8)Yb(4)Se(SeSe)(3)(SeSeSePh)(Se(0.38)SePh), and (py)(8)Yb(4)Se(SeSe)(3)(SeSeTePh)(SeTePh), respectively. The SePh and TePh compounds contain a square array of Ln(III) ions all connected to a central Se(2)(-) ligand. Three edges of the square are bridged by diselenide ligands, with the fourth SeSe unit coordinating to an EPh ligand that has been displaced from an inner Yb coordination sphere. Differences in the two compounds have their origin in the relative strength of the Yb-E(Ph) bond. In the TePh compound, there is a complete insertion of Se into the remaining Yb-Te(Ph) bond to give a terminal SeTePh ligand, while in the SePh compound there is a compositional disorder in the structure comprised of a terminal SePh ligand and a minor component that has Se inserted into the Yb-Se(Ph) bond to give a terminal SeSePh ligand. The thiolate compound differs dramatically, crystallizing as a rhombohedral array of four Yb(III) ions connected by a pair of mu(3)-Se(2)(-) ligands, with the edges of the rhombus spanned by alternating diselenide and SPh. The SPh coordinate directly to Yb(III) ions in terminal or bridging modes. Cluster interconversion is facile: (py)(4)Yb(SePh)(2) reduces (py)(8)Yb(4)Se(SeSe)(3)(SeSeSePh)(Se(0.38)SePh) to give the cubane cluster [(py)(2)YbSe(SePh)](4), and the cubane reacts with elemental Se to give (py)(8)Yb(4)Se(SeSe)(3)(SeSeSePh)(Se(0.38)SePh). Upon thermolysis, these compounds give YbSe(x)().     

Cluster core controlled reactions of substitution of terminal bromide ligands by triphenylphosphine in octahedral rhenium chalcobromide complexes

Reactions of rhenium chalcobromides Cs4[{Re6(mu3-S)8}Br6].2H2O, Cs3[{Re6(mu3-Se)8}Br6].2H2O, Cs3[{Re6(mu3-Q)7(mu3-Br)}Br6].H2O (Q = S, Se), and K2[{Re6(mu3-S)6(mu3-Br)2}Br6] with molten triphenylphosphine (PPh3) have resulted in a family of novel molecular hybrid inorganic-organic cluster compounds. Six octahedral rhenium cluster complexes containing PPh3 ligands with general formula [{Re6(mu3-Q)8-n(mu3-Br)n}(PPh3)4-nBrn+2] (Q = S, n = 0, 1, 2; Q = Se, n = 0, 1) have been synthesized and characterized by X-ray single-crystal diffraction and elemental analyses, 31P{1H} NMR, luminescent measurements, and quantum-chemical calculations. It was found that the number of terminal PPh3 ligands in the complexes is controlled by the composition and consequently by the charge of the cluster core {Re6Q8-nBrn}n+2. In crystal structures of the complexes with mixed chalcogen/bromine ligands in the cluster core all positions of a cube [Q8-nBrn] are ordered and occupied exclusively by Q or Br atoms. Luminescence characteristics of the compounds trans-[{Re6Q8}(PPh3)4Br2] and fac-[{Re6Se7Br}(PPh3)3Br3] (Q = S, Se) have been investigated in CH2Cl2 solution and the broad emission spectra in the range of 600-850 nm were observed.     

Intramolecular amine-induced [1,3]-sigmatropic rearrangement in the reactions of aminophosphinites or phosphites with elemental sulfur or selenium

Ether- and thioether-functionalized cyclodiphosphazanes cis-[tBuNP(OCH2CH2EMe)]2 (E = O, 1; E = S, 2) react with 2 equiv of elemental sulfur or selenium to produce dichalcogenides cis-[tBuNP(E)(OCH2CH2EMe)]2 (4-6), whereas the similar reaction of amine-functionalized cyclodiphosphazane cis-[tBuNP(OCH2CH2NMe2)]2 (3) with elemental chalcogen results in the formation of thio- or selenophosphates trans-[tBuNP(O)(ECH2CH2NMe2)]2 (E = S, 7; E = Se, 8) through [1,3]-sigmatropic rearrangement. The X-ray crystal structure of 8 confirms the rearranged product as the trans isomer with a planar P2N2 ring. The equimolar reaction of P(OCH2CH2OMe)3 (9) with elemental sulfur or selenium produces the simple sulfide and selenide E=P(OCH2CH2OMe)3 (E = S, 11; E = Se, 12) derivatives, respectively. In contrast, the reaction between P(OCH2CH2NMe2)3 (10) and S or Se furnishes the rearranged products (13 and 14). The rearrangement reaction was monitored by (31)PNMR spectroscopy, which confirms the formation of selenophosphinic acid as the first step of the rearrangement. The [1,3]-sigmatropic rearrangement presumably takes place through chalcogen-nitrogen interactions.     

Edge-bridged Mo2Fe6S8 to pN-type Mo2Fe6S9 cluster conversion: structural fate of the attacking sulfide/selenide nucleophile

Reaction of the edge-bridged double cubane cluster [(Tp)(2)M(2)Fe(6)S(8)(PEt(3))(4)] (1; Tp = hydrotris(pyrazolyl)borate(1-)) with hydrosulfide affords the clusters [(Tp)(2)M(2)Fe(6)S(9)(SH)(2)](3)(-)(,4)(-) (M = Mo (2), V), which have been established as the first structural (topological) analogues of the P(N) cluster of nitrogenase. The synthetic reaction is an example of core conversion, resulting in the transformation M(2)Fe(6)(mu(3)-S)(6)(mu(4)-S)(2) (C(i)) --> M(2)Fe(6)(mu(2)-S)(2)(mu(3)-S)(6)(mu(6)-S) (C(2)(v)), the reaction pathway of which is unknown. The most prominent structural feature of P(N)-type clusters is the mu(6)-S atom, which bridges six iron atoms in two MFe(3)S(3) cuboidal halves of the cluster. The initial issue in core conversion is the origin of the mu(6)-S atom. Utilizing SeH(-) as a surrogate reactant for SH(-) in the system 1/SeH(-)/L(-) in acetonitrile, a series of selenide clusters [(Tp)(2)Mo(2)Fe(6)S(8)SeL(2)](3)(-) (L(-) = SH(-) (4), SeH(-) (5), EtS(-) (6), CN(-) (7)) was prepared. The electrospray mass spectra of 4 and 6 revealed inclusion of one Se atom in each cluster, and (1)H NMR spectra and crystallographic refinements of 4-7 indicated that this atom was disordered over the two mu(2)-S/Se positions. The clusters {[(Tp)(2)Mo(2)Fe(6)S(9)](mu(2)-S)}(2)(5)(-) (8) and {[(Tp)(2)Mo(2)Fe(6)S(8)Se](mu(2)-Se)}(2)(5)(-) (9) were prepared from 2 and 5, respectively, and shown to be isostructural. They consist of two P(N)-type cluster units bridged by two mu(2)-S or mu(2)-Se atoms. It is concluded that, in the preparation of 2, the probable structural fate of the attacking nucleophile is as a mu(2)-S atom, and that the mu(3)-S and mu(6)-S atoms of the product cluster derive from precursor cluster 1. Cluster fragmentation during P(N)-type cluster synthesis is unlikely.     

Solvothermal synthesis and characterization of two 2-D layered germanium thioantimonates with transition-metal complexes

Two germanium thioantimonates [Co(dien)(2)](2)GeSb(4)S(10) (1, dien = diethylenetriamine) and [Mn(en)(3)]GeSb(2)S(6) (2, en = ethylenediamine) have been solvothermally synthesized and characterized by IR, UV/Vis, fluorescence spectroscopy, elemental analysis, thermogravimetric analysis, powder X-ray diffraction and single-crystal X-ray diffraction. 1 contains heterometallic pseudosemicube [GeSb(2)S(7)] clusters and chain-like Sb(4)S(10) tetramers, which are interconnected to form a unique double layer of [GeSb(4)S(10)](4-) with 10-MR helical channels. 2 features a sheet layer of [GeSb(2)S(6)](2-) with ellipse-like 12-MR, where one [GeS(4)] tetrahedra, one [SbS(3)] trigonal-pyramid and one Ψ-[SbS(4)] trigonal bipyramid are combined to form another heterometallic [GeSb(2)S(8)] cluster as a building unit. 1 and 2 exhibit absorption edges at 2.36 eV and 2.10 eV, respectively. 2 exhibits a fluorescence emission at room temperature.     

Preparation of phthalocyanines with eight benzylchalcogeno substituents from 5,6-dibromo-4,7-diethylbenzo[1,2,3]trichalcogenoles

Benzo[1,2,3]trichalcogenoles with two bromine atoms on the benzene ring, 5,6-dibromo-4,7-diethylbenzo[1,2,3]trichalcogenoles (1a) and (1b) (chalcogen: 1a = S; 1b = Se), were first prepared by treating 2,3,5,6-tetrabromo-1,4-diethylbenzene (TBDEB) with elemental sulfur or amorphous selenium in DBU at 140 degrees C (for 1a) and 100 degrees C (for 1b) for 24 h. The structures of 1a and 1b were verified by NMR spectroscopy, mass spectrometry, and elemental analysis. X-ray crystallographic analysis ultimately showed that the substitution reactions of TBDEB proceeded at the two adjacent bromine atoms. To apply 1a and 1b to construction of phthalocyanine derivatives with sulfur or selenium functional groups, 4,5-bis(benzylchalcogeno)-3,6-diethylphthalonitriles (5a) and (5b) as key intermediates were prepared by way of introduction of alkyl groups (2-cyanoethyl or 4-nitrophenethyl groups) on two chalcogen atoms, substitution of two bromine atoms with nitrile groups, and subsequent exchange of alkyl groups with benzyl groups. Compound 5a was treated with lithium in n-pentanol at 100 degrees C for 1 h to produce 2,3,9,10,16,17,23,24-octakis(benzylthio)-1,4,8,11,15,18,22,25-octaethylphthalocyanine (6a). A similar treatment of 5b in n-hexanol at 100 degrees C for 2 h gave phthalocyanine 6b. The structures of 6a and 6b were determined by (1)H NMR spectroscopy and MALDI-TOFMS. X-ray crystallographic analysis of 6a was also performed. The Q-band absorptions (lambda(max)) for 6a and 6b in UV-vis spectra were observed at 755 nm (log epsilon = 5.1) and 757 nm (log epsilon = 5.1), respectively, and their electrochemical properties were verified by cyclic voltammetry in dichloromethane with Ag/AgNO(3) as a reference electrode. Compounds 6a and 6b were further treated with lithium in THF/NH(3) at -78 degrees C and then with dibutyltin dichloride to produce phthalocyanine derivatives 8a and 8b with four dichalcogenastannole rings by way of octachalcogenate phthalocyanines 7a and 7b.     

Synthesis and controlled hydrolysis of organolanthanide complexes with mono- and dianionic benzimidazole-2-thiolate ligands

Treatment of Cp(3)Er with one equivalent of benzimidazole-2-thiol (H(2)Bzimt) in THF affords the monoanionic HBzimt(-) complex Cp(2)Er(η(2)-HBzimt)(THF)(2) (1). Reaction of Cp(3)Yb with two equivalents of H(2)Bzimt gives complex CpYb(η(2)-HBzimt)(2)(THF) (2) at room temperature. Treatment of Cp(3)Ln with three equivalents of H(2)Bzimt in reflux THF affords the homoleptic Ln(η(2)-HBzimt)(3)(THF)(2) (Ln = Er (3), Y (4)). Cp(3)Ln reacts with 0.5 equivalents of H(2)Bzimt to afford the dianionic Bzimt(2-) complexes [(Cp(2)Ln)(THF)](2)(μ-Bzimt) (Ln = Yb (5), Er (6), Dy (7), Y (8)) in good yields, in which the Bzimt(2-) ligand bridges the two metals in an μ-η(2):η(2) coordination mode. Interestingly, controlled hydrolysis of complexes Cp(2)Ln(η(2)-HBzimt)(THF)(2), CpLn(η(2)-HBzimt)(2)(THF) and [(Cp(2)Ln)(THF)](2)(μ-Bzimt) produces the same tetranuclear complexes [CpLn(μ(3)-OH)(μ-η(1):η(2)-HBzimt)](4) (Ln = Yb (9), Er (10), Y (11)), indicating that the hydrolysis selectivity greatly depends on the number of coordinated cyclopentadienyl groups. All complexes were characterized by elemental analysis, spectroscopic properties and X-ray single crystal diffraction analysis.     

Synthesis and Single Crystal Structure of RbEr_2Cu_3Se_5

1 INTRODUCTION Halide fluxes are excellent media for growing single crystals of chalcogenides[1~3]. It is well known that during the single crystal growth via flux methods, occasional inclusion of the flux elements in the structure leads to the formation of new phases[4~9]. Several rare earth chalcogenides have been prepared through such reactive halid flux methods[4~9]. Thus we used RbCl as reactive flux to explore a new quaternary selenide by the reaction of ErCuSe precursor with Rb…     

Lanthanide-transition metal chalcogenido cluster materials

[(THF)3Sm(SePh)2Zn(SePh)2]n decomposes to give a variety of products, including [(THF)8Sm4Se(SePh)8](2+)[Zn8Se(SePh)16](2-), an ionic cluster that can also be prepared in more than 60% yield by stoichiometric addition of Se to a mixture of Sm(SePh)3 and Zn(SePh)2. The isostructural Nd compound [(THF)8Nd4Se(SePh)8](2+)[Zn8Se(SePh)16](2-) was also prepared by the stoichiometric route to establish the viability of this cluster type with redox-inactive Ln. In addition, the salt [Yb(THF)6](3+)[Fe4Se4(SePh)4](3-) was isolated and structurally characterized. These ionic cluster materials illustrate the difficulties associated with doping Ln ions into covalent metal chalcogenido matrixes.     

Reactions of dichloromethane with chalcogens and dimethyl chalcogenides in the hydrazine hydrate-alkali system

Methods of synthesis of compounds MeY(CH₂Y) _n Me (Y=S, Se, Te; n = 1–3) containing several identical or different chalcogen atoms are suggested. The methods are based on the reactions of dichloromethane with elemental chalcogens (Y^2?) and dimethyl dichalcogenides (MeY^?) activated in the system hydrazine hydrate-alkali. The effect of the chalcogen on the reactivity toward dichloromethane is qualitatively assessed. With elemental tellurium in the system hydrazine hydrate-alkali, reduction of one chlorine atom in dichloromethane and formation of methyltellanyl derivatives are observed.     

Cluster expansion reactions of group 6 and 8 metallaboranes using transition metal carbonyl compounds of groups 7-9

The reinvestigation of an early synthesis of heterometallic cubane-type clusters has led to the isolation of a number of new clusters which have been characterized by spectroscopic and crystallographic techniques. The thermolysis of [(Cp*Mo)(2)B(4)H(4)E(2)] (1: E = S; 2: E = Se; Cp* = η(5)-C(5)Me(5)) in presence of [Fe(2)(CO)(9)] yielded cubane-type clusters [(Cp*Mo)(2)(μ(3)-E)(2)B(2)H(μ-H){Fe(CO)(2)}(2)Fe(CO)(3)], 4 and 5 (4: E = S; 5: E = Se) together with fused clusters [(Cp*Mo)(2)B(4)H(4)E(2)Fe(CO)(2)Fe(CO)(3)] (8: E = S; 9: E = Se). In a similar fashion, reaction of [(Cp*RuCO)(2)B(2)H(6)], 3, with [Fe(2)(CO)(9)] yielded [(Cp*Ru)(2)(μ(3)-CO)(2)B(2)H(μ-H){Fe(CO)(2)}(2)Fe(CO)(3)], 6, and an incomplete cubane cluster [(μ(3)-BH)(3)(Cp*Ru)(2){Fe(CO)(3)}(2)], 7. Clusters 4-6 can be described as heterometallic cubane clusters containing a Fe(CO)(3) moiety exo-bonded to the cubane, while 7 has an incomplete cubane [Ru(2)Fe(2)B(3)] core. The geometry of both compounds 8 and 9 consist of a bicapped octahedron [Mo(2)Fe(2)B(3)E] and a trigonal bipyramidal [Mo(2)B(2)E] core, fused through a common three vertex [Mo(2)B] triangular face. In addition, thermolysis of 3 with [Mn(2)(CO)(10)] permits the isolation of arachno-[(Cp*RuCO)(2)B(3)H(7)], 10. Cluster 10 constitutes a diruthenaborane analogue of 8-sep pentaborane(11) and has a structural isomeric relationship to 1,2-[{Cp*Ru}(2)(CO)(2)B(3)H(7)].