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Metal chalcogenide cluster compounds are interesting substances by virtue of their intrinsic electronic and optical properties and their potential usage as single-source precursors for semiconductor materials. Herein, the synthesis and structural characterization of six new [HgTe]-based cluster compounds derived from bis(2-pyridyl)ditellane (oPy2Te2), and different mercury salts are described: four neutral clusters of the composition [Hg4(PPh3)2(μ-oPyTe)6Cl2] (1), [Hg4(PPh3)2(μ-oPyTe)6Br2] (2), [Hg4(PPh3)2(μ-oPyTe)6I2]⋅DMF (3) and ([Hg8(μ-oPyTe)12SCl2]⋅5.25DMF (4), and the two zwitterionic clusters [Hg8(μ-HoPyTe)0.93(μ-oPyTe)11.07SBr2.93])⋅7.62DMF (5) and [Hg8(μ-HoPyTe)0.83(μ-oPyTe)11.17SI2.83])⋅7.25DMF (6) (oPy = 2-pyridyl). The compounds were studied by single-crystal X-ray diffraction, FT-IR spectroscopy, and confocal Raman microspectroscopy. Furthermore, the optical energy gaps of the compounds were estimated by solid-state UV–Vis diffuse reflectance spectroscopy. The compounds with the smaller core structure (1–3) presented the larger Eg values, confirming small-particle optical properties’ strong dependence on the core structure’s size and composition.

Five new PdII complexes are reported and have been obtained by the reaction of monomeric [Pd(bipy)(py)2]2+, which serves as a builing block, and substituted (ArSe)2 or Pd(SeAr)2. Complexes [Pd2(μ-SeAr)2(bipy)2](PF6)2, Ar = Ph (1), p-ClC6H4 (2), p-FC6H4 (3), [Pd3(μ3-Se)2(bipy)3](PF6)2·5THF (4) and [Pd3(μ-SeMes)4(bipy)2](PF6)2·2MeCN (5) showed that the nuclearity of these structures is affected by electron donating groups (EDGs) and electron withdrawing groups (EWGs) from the selenium-containing ligands, where changing the stoichiometry ratio of the reactants does not affect the number of palladium centers. The distinct behaviors of 1–5 in the solid state, solution phase and gas phase were investigated by single-crystal XRD, NMR and ESI-TOF-MS. In solution, the dinuclear 1–3 structures exist in equilibrium with trinuclear species. In the gas phase, trinuclear and tetranuclear aggregates of 1–3 are detected, as well as dinuclear and tetranuclear aggregates for 5, while compound 4 maintains the same nuclearity. The solid-state electrochemical behavior was studied, and all complexes were electrochemically active, exhibiting irreversible electrochemical processes, where selenium is indicated to be the active species which oxidizes under such conditions. The complexes are potential candidates to act as semiconductor sensitizers for photocatalytic hydrogen evolution, as they absorb in the visible region with optical band gap energies in the range of 2.6 eV.

Reactions of 2,6-dipicolinoylbis(N,N-diethylthiourea), H2Lpy, InCl3, MCl salts (M = Rb+, K+, Na+ or NH4+) and NEt3 in methanol give cationic {2}-metallacryptates of the composition [M⊂{In2(Lpy)3}]+ (M+ = Rb+, K+, Na+ or NH4+). They can be isolated as PF6− salts. The structural characterization of the products by means of spectroscopic methods and X-ray crystallography reveals host–guest assemblies, in which a monovalent guest cation M+ is encapsulated in the cryptand-like host compound {In2(Lpy)3}. The host–guest directional interactions are coordination or hydrogen bonds depending on the nature of the guest cation. A 15N NMR spectroscopic study on the inclusion compound with 15NH4+ cations reveals a dynamic structure of the corresponding {2}-metallacryptate in solution and partial exchange of the ammonium ions by coordinating solvents.

One-pot reactions of 2,6-dipicolinoylbis(N,N-diethylthiourea) (H2L) with Co(CH3COO)2·4H2O and LnCl3, where Ln = La, Ce, Nd, Sm, Gd, Dy, Er, and Yb, in warm methanol in the presence of Et3N, give st...

2-(2-Furyl)-3-hydroxychromone (HL) reacts with MII ions in the formation of quadratic [Cu(L)2] (3), octahedral [M(L)2(OH2)2] (M = Co (1), Ni (2), Zn (4), Mn (5)) and seesaw [M(L)2] (M = Sn (6), Pb (7)) complexes. Recrystallization of complexes 1-3 in presence of pyridine lead to [M(L)2(py)2] (1a-3a) adducts. All compounds were characterized by Fourier transform infrared spectroscopy (FTIR). Complexes 1-7 were analyzed by UV-Vis and diffuse reflectance spectroscopies. The estimated band gap energies range from 2.90-3.15 eV. The crystal structure of complexes 6 and 7 revealed the influence of the stereochemically active lone pair due to their electronic configuration ns2. An intense fluorescence emission band centered at approximately 600 nm (λexc centered at 340 nm) has been observed for complex 6 in the solid state. In N,N‑dimethylformamide (DMF) solution, complex 6 showed two emission bands (468 and 538 nm) when excited from 300 to 380 nm, and only one emission band (468 nm) when excited from 385 to 420 nm.

Phenyltelluroxane clusters of the composition [{(PhTe)19O24}2I18(solv)] (1) are formed during the hydrolysis of [PhTeI3]2 or the oxidation of various phenyltellurium(II) compounds with iodine under hydrolytic conditions. The compounds consist of two half‐spheres with a {(PhTe)19O24}9+ network, which are connected by 18 iodine atoms. The spherical clusters can accommodate solvent molecules such as pyridine or methanol in the center of two rings formed by iodine atoms. The presence of other metal ions during the cluster formation results in a selective replacement of the central {PhTe}3+ units of each half‐sphere as has been demonstrated with the isolation of [{(PhTe)18({Ca(H2O)2}O24}2I16] (2) and [{(PhTe)18({Y(NO3)(H2O)}O24}2I16] (3). A crownether‐like coordination by six oxygen atoms of the telluroxane network is found for the {Ca(H2O}2}2+ and {Y(NO3)(H2O)}2+ building blocks. Mass spectrometric studies show that considerable amounts of the intact clusters are transferred to the gas phase without dissociation., Large telluroxane clusters are formed during the hydrolysis of [PhTeI3]2 or the oxidation of [PhTe]2 with iodine under hydrolytic conditions. They consist of two half‐spheres with {(PhTe)19O24}9+ networks, which are connected by 18 iodine atoms. The central {PhTe}3+ units of each half‐sphere can be replaced by other metal ions. Mass spectrometry shows that the intact clusters are transferred to the gas phase without dissociation.

Three new neutral oxorhenium(V) complexes were prepared with a 5-hydroxy-3-methyl-5-phenyl-pyrazoline-1-(S-benzyldithiocarbazate) ligand (H2bdtc): ReOCl(bdtc)(triphenylphosphine) [1] , ReOBr(bdtc)(triphenylphosphine) [2] and ReO(bdtc)(cysteamine) [3] . These rhenium complexes were characterized based on elemental, ESI(+)-MS, IR, NMR (1H and 31P), and X-ray diffraction analysis. The bdtc ligand took on different coordination arrangements for the three rhenium complexes, a planar conformation for 1 and a facial conformation for complex 3. Complexes 1 and 3 crystallize with monoclinic space groups P21/n and P21/c, respectively. The conformational stability caused by the unimolecular arrangement of the ligands was evaluated by the Density Functional Theory (DFT) calculation with the purpose of determining the balance involving the equilibrium among the possible stereoisomers in isolated phase and solvent. Moreover, frontier molecular orbitals, Natural Bond Orbital (NBO), Quantum Theory of Atoms in Molecules (QTAIM), bond order indices and molecular electrostatic potential analysis were performed to understand the electronic properties.

Nine thiosemicarbazone ligands (H2Ln, n = 1–9) containing benzothiazole or benzoxazole groups at the C(2) atom of the thiosemicarbazone have been prepared and characterized. A crystal structure study was performed on six of these free ligands and the role of the π–π interactions in the molecular association was analyzed. The coordination behavior of the thiosemicarbazones towards the {Re(CO)3}+ fragment was investigated and three types of complexes were obtained: mononuclear fac-[ReX(H2Ln)(CO)3], X = Cl or Br, with bidentate ligands, dinuclear [Re2(HLn)2(CO)6] with monodeprotonated bridging thiosemicarbazonates yielding Re2S2 cores and tetranuclear [Re4(L2)2(CO)12(EtOH)2] with an unusual bideprotonated thiosemicarbazonate ligand. The intermolecular interactions before and after metal coordination were analyzed. In the dinuclear complexes, two different approximate symmetries were observed depending on the relative orientation of the thiosemicarbazonate ligands with respect to the Re2S2 diamond. The intramolecular interactions in the dimers and their relationship with the two possible symmetric dispositions were analyzed. The findings, in conjunction with theoretical calculations, allowed the main stabilizing factors for each type of symmetry to be elucidated.

The deep blue, paramagnetic Cs2[TcII(NO)F5] is formed during reactions of pertechnetate, acetohydroxamic acid, and CsF in aqueous HF. A reaction of Cs2[Tc(NO)F5] with BF3·MeOH in acetonitrile gives yellow blocks of the fluorido-bridged dimer [{TcI(NO)(CH3CN)4}2F](BF4)3. The compound is stable as solid and in acetonitrile solutions. The complex cation contains a bent μ-F– ligand and two linear nitrosyl groups.

Reactions of thiosemicarbazone ligands (H2L1) with [ReX3(NPh)(PPh3)2] (X = Cl or Br) led to the formation of stable rhenium(V) complexes of composition [ReX(NPh)(HL1)(PPh3)]X. The Re(V) complexes have been characterized by diverse techniques including FTIR, 1H and 31P NMR, elemental analysis, HRMS and single-crystal X-ray diffraction analysis. The crystal structures of the complexes rhenium complexes showed the formation a distorted octahedron environment around the Re(V) metal center, with the axial positions being occupied by the halogen atom and by the nitrogen atom from the phenylimido moiety, while the equatorial positions are occupied by the S,N,S-thiosemicarbazonate and the triphenylphosphane ligands. Furthermore, the “3 + 2” mixed ligand complex [Re(NPh)(L1b)(Et2btu)], where HEt2btu is N,N-diethyl-N’-benzoylthiourea, could be obtained from an equimolar reaction of [ReCl(NPh)(HL1)(PPh3)]Cl with the bidentate thiourea in the presence of NEt3. Finally, DFT calculations were applied in order to propose a complex suitable for biocouplings upon substitution of a NH2 group at the 4-position of the phenylimido ligand in [Re(NPh)(L1b)(Et2btu)]. The compounds studied here represent the first examples of phenilimidorhenium(V) complexes with thiosemicarbazones.

In this article we describe the synthesis and characterization of [PhTe(tu)2][PhTeI4] and [MesTe(tu)][PhTeX4] (tu = thiourea, X = Br, I), containing multivalent tellurium species. During the syntheses of the compounds, the formation of different species, such as [PhTe(tu)I] or [I(tu)2][PhTeI4] was found, which were isolated and characterized. Thiourea was used in order to explore the relevance of Te···S bonds in the solid state structures of the products compared to related compounds with Te···X and X···X bonds in their molecular structures. Different types of chalcogen-chalcogen, chalcogen-halogen and halogen-halogen interactions are described by the combination of crystallographic data and computational methods. The nature of these interactions was evaluated by the noncovalent interaction index (NCI), and quantum theory of atoms in molecules (QTAIM) analyses.

2,6-Diacetylpyridine-bis(benzoylhydrazone), H2LPh, reacts with Pb(OAc)2·3H2O and NEt3 as a supporting base forming a polymeric solid of the composition [Pb(LPh)]n. A reaction with pyridine results in cleavage of the polymer and formation of the dimeric, crystalline compound [Pb(py)(LPh)]2. Similar reactions with PbX2 salts (X = Cl, Br, I) also give almost insoluble solids of the tentative composition [Pb(H2LPh)X2]n. After ongoing reactions with DMSO, single deprotonation of the organic ligand and the formation of pseudo-dimeric [Pb(HLPh)X]2 complexes was observed. Depending on the presence of solvent molecules they form different supramolecular aggregates by π–π interactions. The use of Pb(NO3)2 results in a dimeric structure with relatively short Pb–O bonds of 2.442(2) A between the monomeric sub-units. The formed dimers aggregate to a polymeric assembly by hydrogen bonds. The products were studied by spectroscopic methods and X-ray diffraction.

Reactions between [Tc(I)(NO)X2(PPh3)2(CH3CN)] complexes (X = Cl, Br) and KCp form the pseudotetrahedral organotechnetium compounds [Tc(I)(NO)(Cp)(PPh3)X]. The halide ligands can readily be replaced by other halides or organometallic ligands giving access to a novel family of technetium(i) compounds with the robust {Tc(NO)(Cp)(PPh3)}(+) core.

The compounds [Pd2I2{Te((2,6-OCH3)2C6H3)}2(PCy3)2] (1), [Pd2I2{Te((2,6-OCH3)2C6H3)}2(PR2R')2]∙2CH3CN (2), [Pd2{Te((2,6-OCH3)2C6H3)}2(phen)2][Hg2Br6(phen)2] (3), [Pd2Cl2(TePh2)2(TePh)2] ∙ DMF (4), [Pd2(SePh)2(2,2′-bipy)2][HgBr4]∙2DMF (5), [Pd2(SePh)2-(phen)2][HgI4]∙5DMF (6), [Pd2{Te((2,6-OCH3)2C6H3)}2(phen)2][Hg2I6]-[Hg((2,6-OCH3)2C6H3)2] (7) containing [Pd2(µ-ER)2] core (E = Se, Te; R = aryl) were synthesized and characterized by IR spectroscopy, elemental analysis and X-ray crystallography. Intermolecular metallophilic interactions were evaluated through crystallographic studies combined with Density Functional Theory calculations. The structural stability of 4–7 were investigated taking in account the interactions E⋯E, Pd⋯Pd and Pd⋯Hg between [Pd2(µ-ER)2] cores.

Novel, potentially pentadentate ligands (H3L) for an optimal coordination of {MVO}3+ and {MV(NPh)}3+ cores (M = Re, Tc) have been tailored by a computer-aided procedure. They can be prepared by reactions of 2-aminobenzyliminodiacetic acid diethylester with N,N-[(dialkylamino)(thiocarbonyl)]benzimidoyl chlorides and subsequent hydrolysis. The ligands react with [ReOCl3(PPh3)2] or [Re(NPh)Cl3(PPh3)2] under triple deprotonation and form compounds of the general compositions [ReO(L)] and [Re(NPh)(L)], respectively. The organic ligands occupy the remaining five coordination positions of the {ReO}3+ and {Re(NPh)}3+ cores in all compounds studied. The phenylimido complexes hydrolyze in basic media under formation of their oxidorhenium(V) analogs.

A series of lanthanide complexes with general formula [Ln(NTA)3X] were prapared [Ln = Y (a), Er (b), Eu (c), NTA = naphthoyltrifluoroacetone, X = H2O (1), phen = phenanthroline (2), bpyO1 = 2, 2′-bipyridine N-oxide (3), and bpyO2 = 2, 2′-bipyridine-N,N′-dioxide (4)]. The crystal structures of [Eu(NTA)3bpyO2] (4b), [Er(NTA)3bpyO1] (3c), and [Er(NTA)3phen] (2c) were determined. X-ray crystallographic analysis reveals that the complexes are of mononuclear structure with three NTA and one ancillary ligand. The photoluminescence spectra of 3c and 4b exhibit strong characteristic emissions arising from Eu3+ central ion due to the efficient sensitization of bpyO1 and bpyO2, respectively.

A novel aroylbisthiourea, H3pyr(Et2tu)2 (V), has been prepared from 2,5-pyrroledicarboxylic chloride, NH4SCN and diethylamine. The compound reacts with (NBu4)[ReOCl4] in MeOH under formation of the dimeric oxidorhenium(V) complex [{ReO(OMe)}2{Hpyr(Et2tu)2}2] (VI), which undergoes a condensation in wet acetonitrile and forms the μ-oxido-bridged tetramer [(Re2O3)2{Hpyr(Et2tu)2}4] (VII). The pyrrole rings remain protonated and do not contribute to the coordination of the transition metal. The tetrameric complex is able to accommodate a molecule of water in its molecular cavity.

Bis(2-pyridyl)diselenoethers with the general formula (2-PySe)2(CH2)n [n = 1, 3 and 4] react with CuI, AgNO3, CuCl2·2H2O and CoCl2·6H2O resulting in the formation of products with molecular or multidimensional structures depending on the stoichiometry of the reactants and the conditions applied. The versatility of this class of selenium-containing ligands is demonstrated with the synthesis and structural characterization of six new complexes of the composition [CuCl2{(2-PySe)2CH2}]n (1), [Cu4I4{(2-PySe)2CH2}2] (2), [CuCl2{(2-PySe)2(CH2)3}2] (3), [CoCl2{(2-PySe)2(CH2)3}]n (4), [Ag{(2-PySe)2–(CH2)}3]n(NO3)n (5) and [CuCl2{(2-PySe)2(CH2)4}]n (6), respectively. The Cu(I) complex (2) was tested as catalyst in cross-coupling reactions.

The reaction of isophthaloylbis(N,N-diethylthiourea), H2L1, with FeCl3·6H2O gives the dinuclear tris-complex [Fe2(L1)3] (5), possessing a cryptand-like structure. A similar reaction with the ligand 2,6-dipicolinoylbis(N,N-diethylthiourea), H2L2, however, results in the formation of the anionic, mononuclear Fe(III) complex [Fe(L2)2]− (6), which could be isolated as its “Tl+ salt” by the subsequent addition of Tl(NO3). A tighter view to the solid state structure of the obtained product, however, characterizes compound 6 as a one-dimensional coordination polymer, in which four-coordinate Tl+ ions connect the {[Fe(L2)2]−} units to infinite chains. When Fe3+ ions and Tl+ ions are added to H2L2 simultaneously in a one-pot reaction, a different product is obtained: a cationic trinuclear complex of the composition {M⊂[Fe2(L2)3]}+. It has been isolated as a PF6– salt and represents a {2}-metallacryptate with a nine-coordinate Tl+ ion in the central void. Structurally related products of the compositions {M⊂[Fe2(L2...

Reactions of 3,3,3′,3′-tetraethyl-1,1-isophthaloylbis(thiourea), H 2 L1a, with InCl 3 , Pb(acetate) 2 , [AuCl(PPh 3 )] and [CuCl(PPh 3 )] 4 gave complexes of the compositions [In 2 (L1a-κ O , S ) 3 ], [{Pb(L1a-κ O , S )} 2 ] ∞ , [{Au(PPh 3 )} 2 (L1a-κ S )] and [{Cu(L1a-κ O , S )} 2 ], respectively. The products have been studied spectroscopically and by single-crystal X-ray diffraction. Depending on the specific requirements of the metal ions used, complexes of completely different basic structures have been obtained: a binuclear complex with two octahedrally coordinated indium atoms, a polymeric lead compound with two differently coordinated Pb 2+ ions, a binuclear gold compound in which two {Au(PPh 3 )} + building blocks are connected by a L1a 2− ligand and a binuclear copper(II) complex with two cis-coordinated metal centers.

N-(Dialkylthiocarbamoyl)-N′-picolylbenzamidines (HLEt and HLMorph) react with NiCl2, CuCl2 and [PdCl2(MeCN)2] with the formation of complexes of the general composition [M(LR)Cl] (M = Ni (1), Pd (2)) and the dimeric complexes [{Cu(LR)Cl}2] (3). The molecular structures of complexes 1 and 2 exhibit a square-planar coordination sphere, in which the organic ligands coordinate in a S,N,N coordination mode. The two subunits of 3, the arrangement of each is similar to those of 1 and 2, are connected via two weak Cu–Cl′ bonds. The copper complexes [{Cu(LR)Cl}2] (3) are slowly oxidized under aerobic conditions to give [{Cu(∗LR)Cl}2] complexes (4), where H∗LR = N-(dialkylthiocarbamoyl)-N′-picolinoylbenzamidines. Complexes 1 and 2 show a very weak reduction of the growth of human MCF-7 breast cancer cells. Complexes 4, however, possess a remarkable cytotoxicity with IC50 values within the range 0.40–1.05 μM. Compounds 3 are likely converted to 4 under the conditions of the cytotoxicity assay, and consequently exhibit IC50 values very similar to those found for 4.

Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:25:30Z No. of bitstreams: 0Bitstream added on 2014-05-27T14:36:11Z : No. of bitstreams: 1 2-s2.0-79952004829.pdf: 909499 bytes, checksum: fc1e013a3cbd9b8e53c179e18c451644 (MD5) Made available in DSpace on 2014-05-27T11:25:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-03-24 The reaction of 2,6-diformylpyridine-bis(benzoylhydrazone) [dfpbbh] and 2,6-diformylpyridine-bis(4-phenylsemicarbazone) [dfpbpsc] with lanthanides salts yielded the new chelates complexes [Eu(dfpbpsc-H +) 2]NO 3 (1), [Dy(fbhmp) 2][Dy(dfpbbh-2H +) 2]·2EtOH·2H 2O (fbhmp = 2-formylbenzoylhydrazone-6-methoxide-pyridine; Ph = phenyl; Py = pyridine; Et = ethyl) and [Er 2(dfpbbh-2H +) 2(μ-NO 3)(H 2O) 2(OH)]·H 2O. X-ray diffraction analysis was employed for the structural characterization of the three chelate complexes. In the case of complex 1, optical, synthetic and computational methods were also exploited for ground state structure determinations and triplet energy level of the ligand and HOMO-LUMO calculations, as well as for a detailed study of its luminescence properties. © 2010 Elsevier Ltd. All rights reserved. Universidade Federal de Santa Maria UFSM Departamento de Química, 97105-900 Santa Maria, RS Universidade Estadual Paulista UNESP Laboratório de Materiais Luminescentes, Rua Francisco Degni s/n, 14800-900 Araraquara, SP Freie Universität Berlin Institute of Chemistry and Biochemistry, Fabeckstr. 34-36, D-14195 Berlin Universidade Estadual Paulista UNESP Laboratório de Materiais Luminescentes, Rua Francisco Degni s/n, 14800-900 Araraquara, SP

Bis(2-pyridyl) diselenide (2-py2Se2, 1) reacts with [ReOCl3(PPh3)2] under the formation of the unusual oxidorhenium(V) complex [ReOSe(2-pySe)3], which was isolated in crystalline form and studied by spectroscopic methods and X-ray diffraction. The oxidorhenium(V) core is bonded to three 2-pyridineselenolato ligands together with a selenium(0) atom. While the rhenium atom is coordinated in a common distorted octahedral coordination sphere, the selenium(0) atom shows a bent T-shaped coordination with Se N bonds of 2.13 (1) and 2.28 (1) A and a Se Re bond of 2.387 (1) A. The oxidation state of the Se(0) atom has been analyzed using calculated atomic charges and the electron localization function (ELF).

Reactions of (NBu 4 )[ReOCl 4 ] with N-(N",N"-dialkylaminothiocarbonyl)-N'-(2-hydroxyphenyl)benzamidines (H 2 L 1 ) give complexes of the compositions [ReOCl(L 1 )] (1), cis-[ReO(L 1 )(OMe)] (2), or cis,cis-[{ReO(L 1 )} 2 O] (3) depending on the conditions applied. Compound 3 contains a bridging oxygen atom in the cis position to the terminal oxido ligands of both rhenium atoms. The analogous dimeric, sulfur-bridged compound [{ReO(L 1 )} 2 S] (4) was obtained by the reaction of 1 with Na 2 S.

Reactions of 2-(diphenylphosphinomethyl)aniline, H(2)L(2), with (NBu(4))[ReOCl(4)] yield different oxo rhenium(V) complexes depending on the conditions applied. This comprises monomeric compounds such as [ReOCl(3)(H(2)L(2))] (1), [ReOCl(2)(OMe)(H(2)L(2))] (2), or [ReO(2)(H(2)L(2))(2)]Cl (5) as well as the dimeric μ-oxo complex [{ReOCl(2)(H(2)L(2))}(2)]O] (3) and the oxo-bridged trimer [{ReOCl(H(2)L(2))}O](3) (4). The latter compound represents the first example of a hitherto unknown trinuclear, cyclic oxo(V) core. [{ReOCl(H(2)L(2))}O](3) contains a tensed 6-membered metallacycle, which readily undergoes rearrangements and reactions with additional ligands. Compounds of the compositions 5 and [ReO(2)(H(2)L(2))(H(2)L(1))]Cl (6) were isolated either from the decomposition of 4 in CH(2)Cl(2)/n-pentane or from reactions with 2-(diphenylphosphino)aniline, H(2)L(1).

2,3-Dihydroxynaphthalene (H2dhn) reacts with [ReOCl3(PPh3)2] or [ReOBr3(PPh3)2] in a 1:1 molar ratio with formation of the isostructural complexes [ReOCl2(PPh3)2(Hdhn)] (4) and [ReOBr2(PPh3)2(Hdhn)] (5). They have distorted octahedral coordination spheres with the halide and the triphenylphosphine ligands arranged in equatorial trans positions to each other. The Hdhn– ligand coordinates monodentately in trans position to the oxo ligand. Intramolecular hydrogen bonds between the Hdhn– and the halogeno ligands stabilize this coordination mode. The products represent the first examples of oxorhenium(V) complexes with monodentate catecholate-type ligands.

AgTcO(4) reacts with R(3)ECl compounds (E = C, Si, Ge, Sn, Pb; R = Me, (i)Pr, (t)Bu, Ph), (t)Bu(2)SnCl(2), or PhMgCl under formation of novel trioxotechnetium(VII) derivatives. The carbon and silicon derivatives readily undergo decomposition, which was proven by (99)Tc NMR spectroscopy and the isolation of decomposition products such as [TcOCl(3)(THF)(OH(2))]. Compounds [Ph(3)GeOTcO(3)], [(THF)Ph(3)SnOTcO(3)], [(O(3)TcO)Sn(t)Bu(2)(OH)](2), and [(THF)(4)Mg(OTcO(3))(2)] are more stable and were isolated in crystalline form and characterized by X-ray diffraction.

The reaction of dibenzoylmethane (HDBM) with [RuCl2(PPh3)3] in benzene in the presence of a supporting base (Et3N) under reflux gives two different complexes, the side product as a green-yellow Ru(III) compound of composition [RuIIICl2(DBM)(PPh3)2] (2) and the main product as a red Ru(II) complex of composition [RuII(DBM)2(PPh3)2] (3). The products were studied by spectroscopic methods, cyclic voltammetry and X-ray single crystal diffraction. The molecular structure of 2 shows a distorted octahedral environment around the Ru atom with two phosphine ligands in trans positions. The octahedral complex 3 shows a cis arrangement of two phosphine ligands.

The reaction of cis-[RuCl2(P–P)(N–N)] type complexes (P–P = 1,4-bis(diphenylphosphino)butane or (1,1′-diphenylphosphino)ferrocene; N–N = 2,2′-bipyridine or 1,10-phenantroline) with monodentate ligands (L), such as 4-methylpyridine, 4-phenylpyridine and benzonitrile forms [RuCl(L)(P–P)(N–N)]+ species. Upon characterization of the isolated compounds by elemental analysis, 31P{1H} NMR and X-ray crystallography it was found out that the type of the L ligand determines its position in relation to the phosphorus atom. While pyridine derivatives like 4-methylpyridine and 4-phenylpyridine coordinate trans to the phosphorus atom, the benzonitrile ligand (bzCN), a good π acceptor, coordinates trans to the nitrogen atom. A 31P{1H} NMR experiment following the reaction of the precursor cis-[RuCl2(dppb)(phen)] with the benzonitrile ligand shows that the final position of the entering ligand in the complex is better defined as a consequence of the competitive effect between the phosphorus atom and the cyano-group from the benzonitrile moiety and not by the trans effect. In this case, the benzonitrile group is stabilized trans to one of the nitrogen atoms of the N–N ligand. A differential pulse voltammetry experiment confirms this statement. In both experiments the [RuCl(bzCN)(dppb)(phen)]PF6 species with the bzCN ligand positioned trans to a phosphorus atom of the dppb ligand was detected as an intermediate complex.

Novel rhenium complexes containing the maltolate (mal) or kojate (koj) anions as chelating ligands have been synthesized: [ReOCl(mal)2] (1), [ReOCl2(mal)(PPh3)] (2), [ReOBr2(mal)(PPh3)] (3), [ReOCl2(koj)(PPh3)] (4) and [ReOBr2(koj)(PPh3)] (5). The products have been characterized by FTIR, 1H, 13C, and 31P NMR spectroscopies and elemental analysis. The crystal and molecular structures of all complexes were determined. Complex 1 crystallizes monoclinic, space group C2/c, Z = 8. It contains two O,O′-bidentate maltolate ligands and one chloro ligand at the (ReO)3+ unit, so that a distorted octahedral geometry is adopted by the six-coordinated rhenium(V) center. The chloro ligand occupies a cis position to the oxo ligand. Complexes 2 and 3 are isostructural and crystallize orthorhombic, space group Pbca and Z = 8. The isostructural complexes 4 and 5 crystallize monoclinic, space group P21/n and Z = 4. In complexes 2–5, the (ReO)3+ unit is coordinated by a monoanionic O,O-bidentate unit of the maltolate (2 and 3) or kojate (4 and 5) ligand, one triphenylphosphine and two halogeno ligands (Cl in 2 and 4; Br in 3 and 5), with the rhenium(V) center in a distorted octahedral environment. The halide ligands are in cis positions to each other.

The novel ferrocenylcarbaldehyde benzoylhydrazone ligand H(Fe)L 1 has been prepared and its reaction with fac -[ReBr(CO) 3 (CH 3 CN) 2 ] in chloroform gave [ReBr(CO) 3 {H(Fe)L 1 }] in good yield. Both compounds have been characterized by elemental analysis, MS, IR, UV–Vis and 1 H NMR spectroscopic methods and their structures elucidated by X-ray diffraction. Four crystallographically independent molecules of H(Fe)L 1 are associated by N1–H and N2 or O atoms of a neighbouring ligand or methanol molecules to give chains running along the b axis. The hydrazide group is O,N-bidentate and affords a five-membered chelate ring in the rhenium complex. The geometry around the metal is fac -octahedral. The intermolecular associations based on C(Fc)–H⋯O hydrogen bonds are also discussed.

Summary (1) C11H17IN2STe, M r = 463.83, P21/n, a = 7.6582(8), b = 13.8008(9), c = 15.026(3) Å, β = 96.233(12)°, Z = 4, R 1 = 0.0318. (2) C15H19IN2STe, M r = 513.88, P21/n, a = 8.434(5), b = 11.697(5), c = 18.472(5) Å, β = 98.556(5)°, Z = 4, R 1 = 0.0236. The synthesis of the aryltellurenyl N,N′-tetramethylthiourea (tmtu) iodide has been performed by ligand exchange with potassium iodide and the corresponding aryltellurenyl(tmtu) bromide. In both structures the tellurium atom is primarily three-coordinated, being bonded to a carbon atom of the organic ring and, in directions nearly perpendicular to the Te—C bond, to one tmtu sulfur atom and one iodine. In addition there are Te…secondary bonds, joining the molecules in centrosymmetric dimers, which in turn are joined through C—H…I and C—H…S interactions, in (1) and (2) respectively.

Dimeric complexes of composition [Re2X2(CO)6(HL)2] were obtained by reaction of fac-[ReX(CO)3(CH3CN)2] (X = Cl, Br) with 4-acetylpyridine thiosemicarbazone (HLH) and derivatives in which the thioamide nitrogen bore Me or Ph (HLMe and HLPh, respectively). In these complexes, which were characterized by X-ray crystallography and FAB, IR and 1H NMR spectroscopies, the thiosemicarbazone ligands bridge between two rhenium atoms by coordination of their Npyridine and S atoms. This coordination mode is unusual in that it does not involve any of the thiosemicarbazide nitrogen atoms. The isolation of dimeric complexes rather than monomers or polymers seems to have been due to their poor solubility and rapid precipitation from the reaction medium. [Re2Cl2(CO)6(HLH)2] (1a) was isolated in unsolvated form and as its acetone and acetonitrile solvates; [Re2Br2(CO)6(HLH)2] as its methanol solvate; and all the other complexes as acetone solvates. In all the solvated crystals except those of [Re2Cl2(CO)6(HLPh)2] (3a), all the solvent molecules are hydrogen-bonded to the complex, and in those of [Re2X2(CO)6(HLH)2] these hydrogen bonds contribute significantly to the cohesion of the structure (in particular, in [Re2Br2(CO)6(HLH)2]·2CH3OH there are no hydrogen bonds directly linking the dimers). In 3a·2(CH3)2CO the dimers are linked by N–H⋯π and C–H⋯O interactions, and the non-hydrogen-bonded solvent molecules occupy channels with interatomic long and short diameters of 8.5 and 5.6 A, respectively.

2,4,6-Triphenylphenyltellurium(IV) triiodide, (2,4,6-Ph 3 C 6 H 2 )TeI 3 , can be obtained by the reaction of the corresponding ditelluride {(2,4,6-Ph 3 C 6 H 2 )Te} 2 with iodine under an atmosphere of dry nitrogen in toluene. The apparent bisphenoidal coordination sphere of the central tellurium atom is extended by the presence of intermolecular Te⋯I and I⋯I secondary bonds which form chains along the crystallographic a axis. Weak intramolecular interactions with one of the phenyl rings of the (2,4,6-Ph 3 C 6 H 5 ) unit completes the pseudo-octahedral coordination geometry around each tellurium atom. A comparison of the structure of (2,4,6-Ph 3 C 6 H 2 )TeI 3 with the bonding situations in other organotellurium(IV) triiodides suggests a strong dependence of the formation of supramolecular assemblies on the nature of the organic substituents.

The compounds [Hg2(μ—SePh)2(SePh)2(PPh3)2] (I) and [Hg3Br3(μ—SePh)3] · 2 DMSO (II) are formed by reactions of [Hg(SePh)2] with PPh3 in THF(I) or with HgBr2 in DMSO (II) at room temperature. X—ray crystallography reveals that the cluster I consists of a distorted square built by each two Hg and Se atoms. The Hg atoms have almost tetrahedral co-ordination environments formed by selenium atoms of two (μ-—SePh) ligands and Se and P atoms of terminal —SePh and PPh3 ligands. The compound II is a six-membered ring with alternating Hg and Se atoms in the chair conformation. Two DMSO molecules occupy positions below and above the [Hg3Se3] ring with the oxygen atoms directed to the centre of the ring. Synthese und Strukturen der Cluster [Hg2(μ—SePh)2(SePh)2(PPh3)2] und [Hg3Br3(μ—SePh)3] · 2 DMSO Die Clusterverbindungen [Hg2(μ-SePh)2(SePh)2(PPh3)2] (I) and [Hg3Br3(μ-SePh)3] · 2 DMSO (II) entstehen bei Reaktionen von [Hg(SePh)2] mit PPh3 in THF (I) bzw. mit HgBr2 in DMSO (II). Die Strukturen der Produkte wurden kristallographisch aufgeklart. Das Zentrum von [Hg2(μ-SePh)2(SePh)2(PPh3)2] besteht aus einem verzerrten Quadrat aus zwei Hg- und zwei Se-Atomen. Die Quecksilberatome sind nahezu tetraedrisch koordiniert. Ihre Koordinationssphare wird aus den Se-Atomen zweier (μ-—SePh)-Liganden und den Se und P-Atomen terminaler —SePh- und PPh3-Einheiten gebildet. Die Verbindung II besteht aus einem sechsgliedrigen Ring, in dem alternierend Hg- und Se-Atome angeordnet sind. Oberhalb und unterhalb der Ringebene sind DMSO-Molekule angeordnet, deren Sauerstoffatome in Richtung der Ringebene weisen.

Four new alkylammonium bis(benzohydroximato)borates have been prepared and characterized by elemental analysis, IR and 1 H NMR spectra. The crystal and molecular structures of dicycohexylammonium bis(benzohydroximato)borate chloroform solvate (1/ CHCl3) and tetra-n -propylammonium bis(benzohydroximato)borate (3 )h ave been determined by X-ray diffraction methods. In both examples the bis(hydroximato)borate anions show the expected spirochelate structure with slightly distorted tetrahedral BO4 coordination. The C� /N as well as the C � /O bonds within the chelate rings have considerable double bond character. Bond lengths and angles of the BONCO heterocyle are in good agreement with those observed in N -methylacetohydroxamatoboron complexes (Can. J. Chem. 55 (1977) 1, Can. J. Chem. 56 (1978) 1676). In the crystal structure of 1/CHCl3 the bis(benzoydroximato)borate anions are linked to the dicyclohexylammonium cations by strong N� /H O and N � /H N hydrogen bonds. # 2002 Elsevier Science Ltd. All rights reserved.

The reactions of [ReBr(CO) 5 ] with ferrocenylcarbaldehyde thiosemicarbazones HL with different groups attached to the amide nitrogen (R=H, Me, Ph) yielded complexes [ReBr(CO) 3 (HL)] ( 1 ) in which, according to X-ray studies of 1a ·{(CH 3 ) 2 CO} and 1b ·1/2{CH 2 Cl 2 }, the thiosemicarbazone is N , S -bidentate and the geometry around the metal fac -octahedral. Compounds of formula [ReL(CO) 3 ] 2 ( 2 ) were then prepared by reaction of the corresponding adduct 1 with NaOMe in acetone. A complex of formula [ReL 2 (CO) 3 ] 2 ( 2b ′) was also obtained as a dissolvate by slow concentration of a solution of 1b in acetone. Single crystals of 2a and 2b obtained from the mother liquors are composed of centrosymmetric dimers formed by ReSRe bridges, where S is the thiolic sulfur of an N , S -bidentate thiosemicarbazonato ligand. Although 2b ·2{(CH 3 ) 2 CO} and 2b ′·2{(CH 3 ) 2 CO} have similar co-ordination spheres, they differ as regards the configuration of the thiosemicarbazonato ligand about the azomethine bond and certain bond lengths (notably ReN); it seems likely that the configuration of L 2− determines how close the rhenium can approach the N atom of the ligand, and hence the delocalization of the π electrons in the CNN fragment of the thiosemicarbazide chain. The mass, IR and UV–vis spectra of the complexes, and their electrochemical behavior, are also discussed.

[ReN(Et2dtc)2(Me2PhP)] (Me2PhP = Dimethylphenylphosphan, Et2dtc- = Diethyldithiocarbamat) reagiert mit SbCl3 in Dichloromethan unter Bildung von [{ReN-(Me2PhP)(Et2dtc)Cl}2{ReN(Et2dtc)2}2{SbCl3}2]. In dieser Verbindung wird ein {Re≡N-}4-Ring mit asymmetrischen Nitridobrukken durch die zusatzliche Koordination von SbCl3 an die Chloroliganden und Schwefelatome der Dithiocarbamatliganden stabilisiert. Der Mehrkernkomplex zersetzt sich beim Erhitzen in Acetonitril und aus den gebildeten Fragmenten entstehen der wiederum nitridoverbruckte Komplex [ReN(Me2PhP)(Et2dtc)Cl]4 und [Re-N(Et2dtc)2]. Die mehrkernigen Rheniumverbindungen wurden mit Hilfe der Kristallstrukturanalyse untersucht. Wahrend das 8-gliedrige {Re≡N-}4-Ringsystem in [{ReN(Me2PhP)(Et2dtc)Cl}2{ReN-(Et2dtc)2}2{SbCl3}2] nahezu planar ist, ist das in [ReN(Me2Ph-P)(Et2dtc)Cl]4 deutlich verzerrt und zeigt bei einem Blick entlang der diagonal zueinander angeordneten Rheniumatome V-Form mit einem Diederwinkel von 47, 88(2)° zwischen den beteiligten Flachen. [{ReN(Me2PhP)(Et2dtc)Cl}2{ReN(Et2dtc)2}2{SbCl3}2] — a Novel Tetranuclear Rhenium Complex with Asymmetric Nitrido Bridges The reaction of [ReN(Et2dtc)2(Me22hP)] (Me2PhP = dimethylphenylphosphine, Et2dtc- = diethyldithiocarbamate) with SbCl3 in dichloromethane results in the formation of [{ReN(Me2PhP)(Et22tc)Cl}2{ReN(Et2dtc)2}2{SbCl3}2]. A {Re≡N-}4 ring with asymmetric nitrido bridges is stabilised by the co-ordination of SbCl3 onto the chloro ligands and sulphur atoms of the dithiocarbamates. The compound decomposes upon heating in acetonitrile and the fragments of the tetrameric complex re-arrange to form [ReN-(Me2PhP)(Et2dtc)Cl]4 and [ReN(Et2dtc)2]. The multinuclear rhenium compounds have been studied by X-ray crystallography. The 8-membered {Re≡N-}4 ring system in [{ReN(Me2PhP)(Et2dtc)Cl}22ReN(Et2dtc)2}2{SbCl3}2] is almost planar, while that of [ReN(Me2PhP)(Et2dtc)Cl]4 is clearly V-shaped when viewed down either diagonal Re…Re axis. A dihedral angle of 47.88(2)° has been found between the contributing planes.

The reaction of dibenzenediselenide, (SePh)2, with mercury in refluxing xylene gives bis(benzeneselenolato)mercury(II), [Hg(SePh)2], in a good yield. (nBu4N)[Hg(SePh)3] is obtained by the reaction of [Hg(SePh)2] with a solution of [SePh]– and (nBu4N)Br in ethanol. The solid state structures of both compounds have been determined by X-ray diffraction. The mercury atom in [Hg(SePh)2] (space group C2, a = 7.428(2), b = 5.670(1), c = 14.796(4) A, β = 103.60(1)°) is linearly co-ordinated by two selenium atoms (Hg–Se = 2.471(2) A, Se–Hg–Se = 178.0(3)°). Additional weak interactions between the metal and selenium atoms of neighbouring molecules (Hg…Se = 3.4–3.6 A) associate the [Hg(SePh)2] units to layers. The crystal structure of (nBu4N)[Hg(SePh)3] (space group P21/c, a = 9.741(1), b = 17.334(1), c = 21.785(1) A, β = 95.27(5)°) consists of discrete complex anions and (nBu4N)+ counter ions. The coordination geometry of mercury is distorted trigonal-planar with Hg–Se distances ranging between 2.5 and 2.6 A. Phenylselenolate von Quecksilber(II). Kristall- und Molekulstrukturen von [Hg(SePh)2] und (Bu4N)[Hg(SePh)3] Diphenyldiselenid, (SePh)2, und Quecksilber reagieren in siedendem Xylen unter Bildung von Bis(phenylselenolato)quecksilber(II), [Hg(SePh)2]. (nBu4N) · [Hg(SePh)3] entsteht bei der Umsetzung von [Hg(SePh)2] mit [SePh]– und (nBu4N)Br in Ethanol. Die Kristallstrukturen beider Verbindungen werden beschrieben. Das Quecksilberatom in [Hg(SePh)2] (Raumgruppe C2, a = 7,428(2), b = 5,670(1), c = 14,796(4) A, β = 103,60(1)°) ist linear von zwei Selenatomen koordiniert (Hg–Se = 2,471(2) A, Se–Hg–Se = 178,0(3)°). Die [Hg(SePh)2]-Einheiten sind uber schwache intermolekulare Wechselwirkungen (Hg…Se = 3,4–3,6 A) zu Schichten assoziiert. Die Kristallstruktur von (nBu4N)[Hg(SePh)3] (Raumgruppe P21/c, a = 9,741(1), b = 17,334(1), c = 21,785(1) A, β = 95,25(5)°) besteht aus isolierten Komplexanionen und (nBu4N)+-Kationen. Die Quecksilberatome haben eine trigonal-planare Koordination mit Hg–Se-Abstanden zwischen 2,5 und 2,6 A.

Novel rhenium(V) complexes were isolated from reactions of [NBu(4)][ReOCl(4)] with the potentially pentadentate Schiff base PhP{C(6)H(4)-2-(HC=N(C(6)H(4)-2-OH))}(2), H(2)L(1), and the corresponding amine PhP{C(6)H(4)-2-(CH(2)-NH(C(6)H(4)-2-OH))}(2), H(4)L(2). While the Schiff base undergoes partial hydrolytic decomposition and a redox reaction, the amine remains intact and acts as a pentadentate ligand, which encapsulates the metal atom of the {Re(V)O}(3+) core or stabilizes a {Re(V)Cl}(4+) center by the formation of an imido-type ligand system.

2-Mercapto-methyltetrazolate, Smetetraz–, acts as monoanionic, monodentate ligand in a number of technetium compounds. Anionic TcV complexes of the types [TcO(Smetetraz)4]– and [TcN(Smetetraz)4]2– are formed when (Bu4N)[TcVOCl4] or (Bu4N)[TcVINCl4], respectively, react with Na(Smetetraz). Reduction of the metal takes place in the latter case. (Bu4N)2[TcN(Smetetraz)4] crystallises in the monoclinic space group Pc (a = 9.701(5), b = 17.570(5), c = 16.821(10) A, β = 96.50(3)°, Z = 2). The Tc atom is situated 0.580(3) A above the basal plane of a square pyramid which is formed by the sulfur atoms and the nitrido ligand as its apex. The Tc–S bond lengths lie between 2.384(3) and 2.410(3) A. [Tc(PPh3)(Smetetraz)3(CH3CN)] is formed during the reaction of [TcCl3(PPh3)2(CH3CN)] with NaSmetetraz as blue needles with co-crystallised solvent toluene (space group C2/c, a = 24.188(4), b = 14.373(1), c = 25.617(5) A, β = 109.48(1)°, Z = 8). The metal atom is coordinated by PPh3 and CH3CN in the axial position of a trigonal bipyramid. All three aryl rings are on the sterically less strained side of the plane defined by the sulfur atoms. The Tc–S bond lengths range between 2.233(2) and 2.247(2) A. Technetiumkomplexe mit 2-Mercapto-methyltetrazolat 2-Mercapto-methyltetrazolat, Smetetraz–, fungiert in einer Reihe von Technetiumkomplexen als einzahniger, monoanionischer Ligand. Ausgehend von (Bu4N)[TcVOCl4] oder (Bu4N)[TcVINCl4] und Na(Smetetraz) werden anionische Komplexe der Zusammensetzung [TcO(Smetetraz)4]– bzw. [TcN(Smetetraz)4]2– gebildet. Im Falle der Nitridoverbindung erfolgt eine Reduktion des Metalls. (Bu4N)2[TcN(Smetetraz)4] kristallisiert in der monoklinen Raumgruppe Pc (a = 9,701(5), b = 17,570(5), c = 16,821(10) A, β = 96,50(3)°, Z = 2). Das Tc-Atom befindet sich um 0,580(3) A uber der Grundflache einer quadratischen Pyramide, die aus den vier Schwefelatomen und dem Nitridoliganden gebildet wird. Die Tc–S-Bindungslangen liegen zwischen 2,384(3) und 2,410(3) A. [Tc(Smetetraz)3(PPh3)(CH3CN)] × 0,5 Toluol entsteht bei der Reaktion von [TcCl3(PPh3)2(CH3CN)] mit NaSmetetraz in Form blauer Nadeln (Raumgruppe C2/c, a = 24,188(4), b = 14,373(1), c = 25,617(5) A, β = 109,48(1)°, Z = 8). Das Tc-Atom ist trigonal-bipyramidal mit PPh3 und CH3CN in den axialen Positionen koordiniert. Die Arylringe der Thiolatliganden befinden sich auf der sterisch weniger belasteten Seite des Molekuls. Die Tc–S-Bindungslangen liegen im Bereich zwischen 2,233(2) and 2,247(2) A.

(NBu4)[ReOCl4] reacts with N-picolyl-N′-benzoylthiourea (H2picbtu) in acetone under formation of the deep-green oxorhenium(V) complex (NBu4)2[{Re2O2Cl5(Hpicbtu)}2O], which was studied by X-ray diffraction. Two dimeric units with each one bridging, singly deprotonated thiourea ligand are connected by an oxo ligand. Inside the subunits, Hpicbtu− coordinates as S,O chelate with a six-membered chelate ring to one rhenium atom, while a five-membered chelate ring is established with the second Re atom and the nitrogen atoms of the picolylamine building block. The compound represents one of the very rare examples of anionic μ-oxorhenium(V) complexes.

A one step synthesis of [TcO3]+[SO3F]− is reported. The compound is volatile at room temperature and has according to calculations a tetrahedral coordination around Tc and a monodentate SO3F group. In the solid state the [SO3F]− anion bridges three [TcO3]+ cations, and vice versa. Space group P21/c, Z = 4, lattice dimensions at 173 K: a = 695.4(11), b = 808.6(12), c = 893.3(14) pm, β = 97.36(8)°.

Die paramagnetischen Rhenium(II)-Nitrosylkomplexe [Re(NO)Cl2(PPh3)(OPPh3)(OReO3)], [Re(NO) · Cl2(OPPh3)2(OReO3)] und [Re(NO)Cl2(OPPh3)3](ReO4) entstehen bei der Reaktion von [ReOCl3(PPh3)2] mit NO-Gas in CH2Cl2/EtOH. Im Verlauf der Reaktion konnen diese und zwei weitere ReII-Komplexe mit 5 d5 „low-spin”-Konfiguration EPR-spektroskopisch und massenspektrometrisch nachgewiesen werden. Die Kristallstrukturanalyse weist fur die isolierten Nitrosylkomplexe linear koordinierte NO-Liganden (Re–N–O-Winkel zwischen 171,9 und 177,3°) aus. Im Endprodukt der Reaktion, [Re(NO)Cl2(OPPh3)3][ReO4] (monoklin, P21/c, a = 13,47(1), b = 17,56(1), c = 24,69(2) A, β = 95,12(4)°, Z = 4), sind drei OPPh3-Liganden meridional koordiniert. Die Zwischenprodukte [Re(NO)Cl2(PPh3)(OPPh3)(OReO3)] (triklin, P 1, a = 10,561(6), b = 11,770(4), c = 18,483(8) A, α = 77,29(3), β = 73,53(3), γ = 64,70(4)°, Z = 2) und [Re(NO)Cl2(OPPh3)2(OReO3)] (monoklin P21/c, a = 10,652(1), b = 31,638(4), c = 11,886(1) A, β = 115,59(1)°, Z = 4) konnen neben [Re(NO)Cl3(Ph3P)2], [Re(NO) · Cl3(Ph3P)(Ph3PO)] und [ReCl4(Ph3P)2] bei kurzeren Reaktionszeiten isoliert werden. Synthesis, Structures, and EPR-Spectra of the Rhenium(II) Nitrosyl Complexes [Re(NO)Cl2(PPh3)(OPPh3)(OReO3)], [Re(NO)Cl2(OPPh3)2(OReO3)], and [Re(NO)Cl2(OPPh3)3](ReO4) The paramagnetic rhenium(II) nitrosyl complexes [Re(NO)Cl2(PPh3)(OPPh3)(OReO3)], [Re(NO)Cl2(OPPh3)2 · (OReO3)], and [Re(NO)Cl2(OPPh3)3](ReO4) are formed during the reaction of [ReOCl3(PPh3)2] with NO gas in CH2Cl2/EtOH. These and two other ReII complexes with 5 d5 ”low-spin””-configuration can be observed during the reaction EPR spectroscopically. Crystal structure analysis shows linear coordinated NO ligands (Re–N–O-angles between 171.9 and 177.3°). Three OPPh3 ligands are meridionally coordinated in the final product of the reaction, [Re(NO)Cl2(OPPh3)3][ReO4] (monoclinic, P21/c, a = 13.47(1), b = 17.56(1), c = 24.69(2) A, β = 95.12(4)°, Z = 4). [Re(NO)Cl2(PPh3)(OPPh3)(OReO3)] (triclinic P 1, a = 10.561(6), b = 11.770(4), c = 18.483(8) A, α = 77.29(3), β = 73.53(3), γ = 64.70(4)°, Z = 2) and [Re(NO)Cl2 (OPPh3)2(OReO3)] (monoclinic P21/c, a = 10.652(1), b = 31.638(4), c = 11.886(1) A, β = 115.59(1)°), Z = 4) can be isolated at shorter reaction times besides the complexes [Re(NO)Cl3(Ph3P)2], [Re(NO)Cl3(Ph3P) · (Ph3PO)], and [ReCl4(Ph3P)2].

[Fe(MeCN)6][Fe2OCl6] (2) wird durch Umsetzung einer Losung von FeCl2 in Acetonitril mit trockenem Luftsauerstoff in fast quantitativer Ausbeute erhalten. 2 kristallisiert in der trigonalen Raumgruppe R 3 [a = b = 12.121(1), c = 29.875(6) A; Z = 6]. Das Sauerstoffatom im Fe2OCl6-Anion besetzt die Lage 3 und bedingt damit einen Fe–O–Fe-Winkel von 180°. Eine Verfeinerung in der triklinen Raumgruppe P1 liefert dagegen eine leicht gewinkelte Anordnung des Fe–O–Fe-Fragments. Synthesis and Crystal Structure of [Fe(MeCN)6][Fe2OCl6] [Fe(MeCN)6][Fe2OCl6] (2) is obtained by passing dry air through a solution of FeCl2 in acetonitrile in almost quantitative yield. 2 crystallises in the trigonal space group R 3 [a = b = 12.121(1), c = 29.875(6) A, Z = 6]. The oxygen atom in the Fe2OCl6 anion occupies the 3 position and causes therefore an Fe–O–Fe angle of 180°. The refinement in the triclinic space group P1 leads to a slightly bent arrangement of the Fe–O–Fe fragment.

Starting originally from the organometallic precursor [NEt4]2[TcBr3(CO)3] (1b), substitution reactions were performed with the macrocyclic thioethers 1,4,7-trithiacyclononane (9-ane-S3), 1,4,7,10,13,16-hexathiacyclooctadecane (18-ane-S6), and 3,6,9,13,16,19-hexathiacycloicosanol (20-ane-S6-OH). The corresponding complexes fac-[Tc(9-ane-S3)(CO)3]Br (2), fac-[Tc2(tosylate)2(18-ane-S6)(CO)6] (3), and fac-[Tc2(20-ane-S6-OH)(CO)6][tosylate]2 (5) were isolated in good yields and characterized spectroscopically by IR, 1H, 99Tc NMR, and X-ray diffraction methods. In the case of 18-ane-S6 and 20-ane-S6-OH the formation of the 1:2 as well as the 1:1 complex could be observed in the 99Tc NMR experiment, depending on the ligand to metal ratio. Complex 2 crystallizes in the monoclinic space group P21/c, a = 14.79(2) A, b = 11.691(2) A, c = 16.94(2) A, β = 94.88(6)°, Z = 8. The tripodal ligand is coordinated through the sulfur atoms to the metal center, forming three favorable five-membered chelate rings. Complex 3 cry...