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Two Ni(II) complexes, [Ni(dmoTSCH)Cl] (1) and [Ni(dmoPhTSCH)Cl] (2) of the tridentate thiosemicarbazone ligands diacetylmonooxime thiosemicarbazone (dmoTSCH2) and diacetylmonooxime (4-phenyl)thiosemicarbazone (dmoPhTSCH2) have been synthesized. X-ray crystal structure of [Ni(dmoTSCPhTSCH)Cl] (2) indicates that the Ni(II) assumes a square planar geometry in the complexes, with the ligand coordinated in a monoanionic N,N,S donor mode and the fourth coordination position of Ni(II) is occupied by a chloride ion. Cyclic and differential pulse voltammetric experiments suggest that the Ni(II) complexes can undergo a two electron reduction at about −1.0V. It is shown that the Ni(II) complexes in DMF or DMSO solutions can mimic CO-dehydrogenase activity by oxidizing CO to CO2in presence of a base like NaOAc and a sacrificial electron acceptor like methyl viologen and the colour of the resultant MV.+can be used to monitor the reaction.

A rich variety of chalcogenidoarsenate anions and ligands have been prepared under mild solvothermal conditions in strongly polarizing solvents such as water, methanol and amines in the temperature range 100 - 200 ?C. This review covers synthetic and structural aspects of such species ASxEyz-with particular emphasis being placed on the trends and differences observed for E = S, Se, Te and on developments within the past decade. These include the preparation of quaternary Main Group element chalcogenidoarsenates(III) such as Cs3AsGeSe5and polymeric selenidoarsenates(II, III) such as Cs2As4Se6. A currently expanding area of interest involves the employment of transition metal-polyamine or -polyimine fragments such as {Mn(tren)}2+or {Mn(terpy)}2+as structuredirecting agents. The metal atoms of such cations can be connected to the terminal chalcogen atoms of oligomeric or polymeric anions AsxEy z- to prevent their further condensation or can be directly incorporated into anionic or neutral networks when at least two free coordination sites are available in the fragment. This strategy has led to the characterization of novel ligands including cyclo- [As4S8]4-, As2Se62-, As2Se64-and 18[As4Se72-]. The syntheses and structures of the new compounds Cs5As5Se9and Cs[{Mn(trien)}(AsSe4-K2Se)] ·CH3OH are also presented. Whereas the former phase contains infinite selenidoarsenate(II,III) chains 18[As5Se95-], the [{Mn(trien)}(AsSe4)]- anion of the latter compound represents the first example of a transition metal-containing ternary selenidoarsenate( V)

The rapid DNA intercalation by dinuclear polypyridyl η5C5Me5IrIIIcomplexes of the type [η5C5Me5Irdppz2μL]CF3SO341–4has been studied by UVVis spectroscopy, circular dichroism, viscosity measurements and nuclear magnetic resonance. Whereas the Ir atoms of compounds 1–3are linked by flexible dithiaalkanes of the type L = CH3SCH2nSCH3n= 4–6, compound 4contains cyclic 1,4dithiane as a shorter more rigid bridging ligand. Stable intercalative binding into CT DNA is indicated for 1–3by large increases in the DNA thermal denaturation temperature and by induced negative CD bands at about 300 nm. Viscositymeasurements show that the DNA lengthening induced by the bisintercalators 1–3is about twice that caused by the monointercalator 4. An analysis of the NOE crosspeaks for a 1:1 mixture of 3with the doublestrand decanucleotide d5′GCGCATCGGC3′ demonstrates that 3intercalates in a sequencespecific manner from the minor groove between the base pairs C4–G17 and A5–T16, and T6–A15 and C7–G14.

The RhIIIcomplexes of the type [RhClpptpm]2+[pp = bpy, bpm, phen, tap, dpq, dppz] 4–9have been prepared by stepwise treatment of RhCl3·3H2O or mer,cis[RhCl3DMSOκS2DMSOκO] with the appropriate polypyridyl ligand pp followed by the tripodal ligand trispyrazolylmethane tpm. Intermediates of the type [RhCl3CH3OHpp] 1–3with pp = bpy, phen, dpq were also characterized but exhibit either low 3 or no 1, 2 cytotoxicity. Xray structural analyses of [RhClbpytpm][PF6]24and [RhClphentpm][PF6]26were performed, and the interaction of complexes 4–9with DNA was investigated by CD and UVVis spectroscopy and by gel electrophoresis. CD and viscosity studies confirm strong intercalation of dppz complex 9into DNA. Complexes 8and particularly 9IC50= 0.43, 0.37 μM are potent cytotoxic agents towards the human cancer cell lines MCF7 and HT29, whereas respectively little complex 6 or no activity complexes 4, 5, 7 is observed for the other members of the series. Our findings indicate that the cytotoxicity is dependent on the hydrophobicity of both the polypyridyl and the facial coligand in these and other halfsandwich RhIIIcomplexes. Irradiation of bpy compound 4in the presence of plasmid pBR322 for 30 min at 311 nm at a molar ratio of r= 0.1 leads to total conversion of the supercoiled form into the nicked version. Although dppz complex 9also functions as a photonuclease under these conditions, the degree of cleavage is much lower. © WileyVCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009

A centrosymmetric binuclear [{CuPPh32}2piperzdtc] 1 [piperzdtc2–= piperazinebisdithiocarbamate] and another mononuclear [{CuPPh32}BzMedtc] 2 BzMedtc–= NbenzylNmethyldithiocarbamate complex have been synthesized and characterized by elemental analyses, IR, 1H, 13C, and 31P NMR spectroscopy and by Xray crystallography. The nonlinear optical properties of 2have been investigated by density functional theory and its electronic absorption bands have been assigned by timedependent density functional theory TDDFT. Both complexes are weakly conducting σrt 10–8S cm–1 because of the absence of M···SS···S intermolecular stacking and exhibit semiconductivity with band gaps of 0.94 and 1.24 eV, respectively.© WileyVCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009

Hydrothermal reaction of [MnCl2(terpy)] with elemental As and Se at 150 °C in 1:2:4 and 1:4:8 molar ratios in the presence of Cs2CO3affords the complexes [{Mn(terpy)}2(As2Se5)]2(1) and [{Mn(terpy)}2(As4Se8)] (2), respectively. 1contains dipyramidal [As2Se5]4−ligands that bridge three MnIIatoms in a tetradentate μ3‐1κ2Se1,Se2:2κSe4:3κSe5manner. The tetranuclear complex is centrosymmetric and exhibits a central 8‐membered (MnSeAsSe)2ring. Cyclic [As4Se8]4−ligands are present in the centrosymmetric dinuclear complex 2and chelate the Mn(II) atoms through adjacent terminal Se atoms. Both 1and 2are linked into infinite chains through weak Mn···Se interactions. [{Mn(terpy)}2(As4S8)] (3) and $_{\infty}^{1}\rm [{Mn(terpy)}(As_{2}S_{4})]$(4) can be obtained by hydrothermal reaction of [MnCl2(terpy)] with As2S3at respectively 150 °C and 190 °C. Whereas 3exhibits an identical connectivity pattern to that of 2, the coordination polymer 4contains vierer$_{\infty}^{1}\rm [AsS_{2}^{-}]$chains that coordinate {(terpy)Mn}2+fragments in a bidentate manner through terminal S atoms. The complex $_{\infty}^{1}\rm [{Mn(tren)}\textrm{ } (As_{4}S_{7})]$(5) contains $_{\infty}^{1}\rm [As_{4}S_{7}^{2-}]$double chains and results from the analogous hydrothermal reaction of [MnCl2(tren)] with As2S3at 150 °C.

Solvothermal reaction of {(L)Mn}2+fragments (L = tren, cyclam, tacn, terpy) with Se in the presence of a mineralizer A2CO3(A = Na, Cs) at 150 °C leads to formation of polyselenide complexes, in which the nuclearity of the $\rm Se^{\2-}_{n}$(n= 4−6) ligands can depend on the polarity of the reaction medium or the hapticity and binding mode of the coligand L. For instance, whereas methanolothermal treatment of [MnCl2(tren)] with Se affords the 1D polymers $^{1}_{\infty}\rm [Mn_{2}(Se_{4})_{2}(tren)_{2}]$(1a) and $^{1}_{\infty}\rm [Mn_{2}(Se_{4})(tren)]$(1b), employment of superheated water as the reaction medium allows the isolation of dinuclear [{Mn(Se6)(tren)}2]. Whereas 1acontains both bridging μ‐1κSe1:2κSe4and terminal κSe1tetraselenide ligands, only the former mode is adopted by the $\rm Se^{\2-}_{4}$ligands in 1b. The analogous reaction of Se with [MnCl2(cyclam)]Cl yields the chelate complex [Mn(Se4)(cyclam)] 2in superheated methanol and dinuclear [{Mn(Se6)(cyclam)}2] (7) under hydrothermal conditions. 7exhibits Cssymmetry and contains two μ‐1κSe1:2κSe6bridging hexaselenide ligands. In contrast to the {(tren)Mn}2+, {(cyclam)Mn}2+and {(terpy)Mn}2+fragments, only one product (3) could be isolated for the tridentate fac‐{(tacn)Mn}2+fragment. Whereas the $\rm Se^{\2-}_{4}$ligands in dinuclear [{(tacn)Mn}2(μ‐Se4)2] (3) adopt a μ‐1κ2Se1,Se4:2κSe4mode, κ2Se1,Se4chelating $\rm Se^{\2-}_{4}$ligands are observed in the methanolothermal product [Mn(Se4)(terpy)] (4). Hydrothermal reaction of Se with [MnCl2(terpy)] affords the chelate complex [Mn(Se5)(terpy)] (5), in contrast. On blocking five of the six octahedral sites by tacn and en ligands, terminal $\rm Se^{\2-}_{5}$ligands were obtained in [Mn(Se5)(en)(tacn)] (6), which can be prepared in both superheated methanol and water.

Solvothermal reaction of [MnCl2(cyclam)]Cl with GeSe2at a 1:1 molar ratio in CH3OH/H2O (1/1) at 150 °C affords the dimanganese(II) complex [{Mn(cyclam)}2(μ‐Ge2Se7)]·CH3OH·1.5H2O (1) with a spirotricyclic [Mn(μ‐Ge2Se7)Mn] core. The strained four‐membered Mn‐Set‐Ge‐Set′ rings (Set= terminal Se atom) exhibit long Mn‐Setdistances in the range 2.725(2)–2.745(2) Å and narrow average Set‐Mn‐Set′ angles of 85.87(4)°. The solvothermal reaction of [MnCl2(cyclam)]Cl with SnSe and Se leads to formation of the analogous complex [{Mn(cyclam)}2(μ‐Sn2Se6.15)] (2), in which bridging [Sn2Se6]4−and [Sn2Se7]4−ligands are disordered at a ratio of 85:15. Employment of [MnCl2(terpy)] under similar conditions generates two complexes of the formula [{Mn(terpy)}2(μ‐Sn2Se6)] 3and 4, of which the former also contains a spirotricyclic core, whereas the Setatoms of the latter coordinate symmetry‐related MnIIatoms in a 1‐D polymer. The Mn‐Setbond distances of 2.584(1) and 2.549(1) Å in the resulting chair‐shaped eight‐membered rings of 4are much shorter than in 1and 2.

Solvothermal reaction of [MnCl2(amine)] (amine = terpy and tren) with elemental As and Se at a 1:1:2 molar ratio in H2O/tren (10:1) affords the dimanganese(II) complexes [{Mn(terpy)}2(μ‐As2Se4)] (1) and [{Mn(tren)}2(μ‐As2Se5)] (2) respectively. The tetradentate [As2Se4]4−bridging ligands in 1contain a central As–As bond and exhibit approximately C2hsymmetry. Pairs of gauchesited Se atoms participate in five‐membered As2Se2Mn chelate rings. In contrast, two AsSe3pyramids share a common corner in the [As2Se5]4−ligands of 2and each coordinates an [Mn(tren)]2+fragment through a single terminal Se atom. Such dinuclear complexes are linked into tetranuclear moieties through weak Se···Mn interactions of length 3.026(3) Å involving one of these terminal Se atoms. At a 1:3:6 molar ratio, solvothermal reaction of [MnCl2(tren)] with As and Se leads to formation of a second dinuclear complex [{Mn(tren)}2(μ‐As2Se6)2] (3), which contains two bridging bidentate [As2Se6]2−ligands. These are cyclic with an As2Se4ring and can be regarded as being derived from [As2Se5]4−anions by formation of two Se‐Se bonds to an additional Se atom.

Two new terephthalato-bridged tetranuclear polymeric NiII complexes, namely [Ni4L41(μ-tp-κ4-O)(H2O)2(μ-tp-κ2-O)]·2C2H5OH·CH3OH·3H2O (1) and [Ni4L42(μ-tp-κ4-O)(H2O)2(μ-tp-κ2-O)]·3H2O (2) [L1 = N-(3-aminopropyl)-5-bromosalicylaldimine and L2 = N-(3-aminopropyl)salicylaldimine], are reported along with the syntheses and structures of the dicyanoargentate-bridged polymeric complexes [Ni(L1)(H2O){Ag(CN)2}]α (3) and [Ni(L3)(MeOH){Ag(CN)2}]α (4) [L3 = N-(3-amino-2,2-dimethylpropyl)-5-bromosalicylaldimine]. All four complexes are found to be effective heterogeneous catalysts for the epoxidation of alkenes such as styrene, α-methylstyrene and cyclohexene in the presence of tert-butyl hydroperoxide. The variable-temperature magnetic susceptibility measurements (300–2 K) of complex 1 show a fair degree of antiferromagnetic coupling between the NiII centers.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

The DNA binding of polypyridyl (pp) (η6-hexamethylbenzene)ruthenium(II) complexes of the type [(η6-C6Me6)RuCl(pp)](CF3SO3) (pp = phen, tap, dpq, dppz, dppn) 1–5 and [(η6-C6Me6)Ru{(NH2)2CS}(pp)](CF3SO3)2 (pp = dpq, dppz, dppn) 6–8 has been studied by UV/Vis spectroscopy, circular dichroism and viscosity measurements. Complexes 3–5, 7 and 8 are potent cytotoxic agents towards the human cancer cell lines MCF-7 and HT-29. Stable intercalative binding into CT DNA is indicated for the dpq and dppz complexes by large increases ΔTm of 12–25 °C in the DNA thermal denaturation temperature for r = [complex]/[DNA] = 0.1. Large viscosity increases for DNA in the presence of 3 and 4 are also in accordance with this binding mode as are the pronounced hypochromic UV/Vis shifts for the π–π* transitions of the dppz ligands of 4 and 7 in the range 360–400 nm. A small ΔTm value of 2 °C and effectively unchanged viscosity suggest that Ru–N (nucleobase) coordinative binding is thermodynamically preferred for the larger polypyridyl ligand of 5 under equilibrium conditions, as is also the case for the small ligands phen and tap in complexes 1 and 2. CD spectra indicate that the B DNA conformation is essentially retained for interaction with the chloro complexes 1–5 but that very significant distortions occur for the thiourea complexes 6–8. The in vitro cytotoxicities of the chloro complexes 3–5 are dependent on the size of the polypyridyl ligand with IC50 values increasing in the order dppn < dppz < dpq: for instance IC50 values of 11.1, 2.12, and 0.13 μM were determined for 3–5 towards MCF-7. These values correlate well with the cellular uptake efficiency which increases from 1.1 over 146.6 to 906.7 ng(Ru)/mg (protein) within the series 3–5. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

Reaction of [MnCl2(tren)] with tren (tris‐(2‐aminoethyl)amine) affords the coordination polymer $^{2}_{\infty}\rm [Mn(tren)_{2}]Cl_{2}$(1), in which the primary amino groups of tridentate tren ligands connect [(tren)Mn]2+fragments into a pseudo 63network. The Mn atoms exhibit a capped octahedral environment with the tertiary N atom of the second tetradentate tren ligand in the capping position. Treatment of MnCl2with Se at 1:2 molar ratio in H2O/tren (10:1) at 150 °C leads to formation of the dinuclear complex [{Mn(μ‐Se6)(tren)}2] (2), which contains tetradentate tren ligands and two bridging hexaselenide ligands in the 1κSe1: 2κSe6mode. In contrast, reaction of [MnCl2(tren)] with Se at a 1:6 molar ratio under similar sovothermal conditions affords the isomeric coordination polymer $^{2}_{\infty}\rm [Mn(\mu-Se_{6})(tren)]$(3). In this complex, Se62−anions now bridge [(tren)Mn]2+fragments into chains, that themselves are linked into polymeric sheets through one of the primary amino groups of the tetradentate tren ligands.

Heating CsAsSe3· 0.5H2O in methanol to 190 °C leads to formation of black Cs2As4Se6(1) together with red Cs4As4Se8and a colourless solution from which the substituted caesium selenidoarsenates(V) Cs2[As(CH3)Se3] · 2H2O (2) and Cs[As(CH3)2Se2] can be obtained as crystalline fractions. Cs2As4Se6contains catena‐hexaselenidotetraarsenate(II,III) anions in which cyclic As3Se5units are linked through corner‐sharing AsSe3pyramids into infinite chains $^{1}_{\infty}\rm [As_{4}Se_{6}^{\phantom{\infty}2-}]$. The Cssymmetric As3Se2five‐membered rings of the As3Se5units display an envelope conformation with an As‐As bond length 2.528(3) Å and As‐Se distances of 2.449(2) and 2.447(2) Å. Cssymmetry is also observed for the discrete tetrahedral [As(CH3)Se3]2−anions of (2).

Cs3Se22can be prepared together with the known compounds Cs2Sn2Se6and Cs4Sn2Se6by reacting Cs2CO3and Sn in a CH3OH/en solution at 120 °C. The presence of CuCl and the macrocyclic ligand 1,10‐dithia‐18‐crown‐6 are essential for product formation. The caesium polyselenide consists of anionic nets $^{3}_{\infty}\rm [Se_{6}^{3-}]$that are separated by two layers of discrete Se8rings. Within the polymeric anions pairs of Se3·−radical anions and Se32−anions are linked through secondary interactions.

The DNA binding of bifunctional IrIII–PtII complexes containing [(η5-Cp*)Ir(dppz)]2+ and [Pt(terpy)]2+ or trans-[PtL2L′]2+ fragments (L = NH3, L′ = DMF; L = H2O, L′ = NH3) bridged by flexible κS:κN(amino)-coordinated methionine-containing peptides has been studied by UV/Vis and CD spectroscopy. Stable intercalative binding of the IrIII fragment of the complexes [{(η5-Cp*)Ir(dppz)}(μ-peptide-κS:κN){Pt(terpy)}](CF3SO3)4 (5) (peptide = H-Gly-Gly-Phe-Met-OH; H-Gly-OH = glycine, H-Phe-OH = L-phenylalanine, H-Met-OH = L-methionine) and 6 [peptide = H-(Ala)4-Met-OH; H-Ala-OH = L-alanine] is indicated by their steady decrease in absorbance at maxima between 350 and 390 nm on titration with CT DNA and by the bathochromic shifts of these maxima. Binding constants Kb of 1.4(4) × 106M–1 for both 5 and 6 and site sizes s of 2.8(1) and 2.2(1), respectively, are in accordance with this monofunctional mode. Both peptide chain length and the site(s) of the labile PtII substituents DMF or H2O play an important role in determining the degree of intercalation of the IrIII fragment and the extent of helix distortion caused by simultaneous covalent binding of PtII centres for the DNA interaction of the complexes [{(η5-Cp*)Ir(dppz)}(μ-peptide-κS:κN){trans-(PtL2L′)}]4+7–10. Whereas both 9 and 10 (L = H2O, L′ = NH3; peptide = H-Gly-Met-OH or H-Gly-Gly-Met-OH) exhibit a high degree of bifunctional binding [9, Kb = 1.1(5) × 106M–1, s = 1.3(1); 10, Kb = 1.4(7) × 106M–1, s = 2.1(1)], CD spectroscopy indicates that a more pronounced reorganisation of the DNA helix is required for the former complex with its shorter peptide. Effective intercalation is also observed for 8 (L = NH3, L′ = DMF; peptide = H-Gly-Gly-Met-OH) but not for 7 with the analogous PtII fragment but a shorter bridging peptide (H-Gly-Met-OH). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Treatment of an acetonitrile solution of CuCN with methylcycloarsoxane (CH3AsO)nat 110 °C affords the coordination polymer ∞3[CuCN{cyclo‐(CH3AsO)4}] (1), in which infinite CuCN zigzag chains are linked by μ‐As1, As3cyclotetramers (CH3AsO)4into an open 3‐D framework. Under similar solvothermal conditions, reaction of CuSCN with (CH3AsO)nin the presence of KSCN leads to metal‐mediated ring expansion of the cyclo‐arsoxane to yield the complex ∞1[{K[cyclo‐(CH3AsO)5]2}Cu(NCS)2] (2). This contains discrete [Cu(NCS‐κN)2{cyclo‐(CH3AsO)5κAs}2]—anions that bridge κ10Ocoordinated potassium cations into infinite chains. In contrast, the structure directing role of the [K(1, 7DT18C6)2]+sandwich building units for the solvothermal product ∞3[{K(1, 7DT18C6)2}Cu6(CN)7] (3) (1, 7DT18C6 = 1, 7‐dithia‐18‐crown‐6) leads to formation of an open ∞3[{Cu6(CN)7}—] framework. Individual [K(1, 7DT18C6)2]+moieties bridge Cu Atoms in a μ‐S1, S7mode and are encapsulated within the large [Cu26(CN)28]2—cages of the cyanocuprate(I) network.

A cyano-bridged Cuii–Niiidimeric complex CuMe6CyNiCN4 has been synthesized and characterized by its single crystal X-ray structure determination. The square planar CuMe6Cy2cation is converted to a distorted trigonal bipyramidal TBP geometry through ligation to one of the cyano groups of NiCN42−in the equatorial plane, keeping the other three as terminal. Inspection of the X-ray data reveals that the Cu–N6–C6 angle of the bridging cyano group is perfectly linear (180°). The room temperature RT EPR spectrum of polycrystalline CuMe6CyNiCN4 is typical for mononuclear copperii complexes of axial symmetry, where the flattened out symmetry axis is characterized by g⊥  2.143 ± 0.005 and g  2.002 ± 0.005. No half field ΔM  2 signals were observed. RT EPR spectrum of polycrystalline CuiiMe6CyClO42yields an EPR signal with g  2.394 ± 0.005 and g⊥  2.045 ± 0.005, indicating that this parent compound has a different geometry than CuMe6CyNiCN4. Variable temperature magnetic moment studies on CuMe6CyNiCN4 indicate a very weak long-range ferromagnetic exchange through hydrogen bonding between copperii ions S  ½. The present investigation provides a unique example where the original square planar CuMe6Cy2moiety rearranges itself to a trigonal bipyramidal geometry under the influence of NiCN42−. This is probably only the second, rare example, and perhaps the first, for a macrocyclic precursor using only one cyano group of NiCN42−for bridging, leading to a discrete dinuclear complex.

Six new tetrahedral chalcocyanide cluster compounds, [{Cu2(dien)3}Re4S4(CN)12] (1), [{Cu(dien)(NH3)}2Re4Se4(CN)12]·2.5H2O (2), [{Cu2(dien)3}Re4Q4(CN)12]·nH2O (Q = Se (3), Te (4)] and [K(H2O)2]2[{Cu3(dien)4}{Re4Q4(CN)12}2]·8H2O where Q = Se (5), Te (6) (dien = diethylenetriamine), have been synthesized by treating aqueous solutions of the salt‐like cluster compounds K4Re4Q4(CN)12·nH2O with solutions of copper(II) chloride in aqueous ammonia containing diethylenetriamine. All six compounds have been characterized by single‐crystal X‐ray diffraction analysis. Compound 1has a chain‐like polymeric structure; orthorhombic, space group Pmn21. Compound 2has a molecular structure; triclinic, space group P$\bar 1$. Compounds 3and 4are isostructural and also exhibit molecular structures; monoclinic, space group P21/n. Compounds 5 and 6 are isostructural and display a cross‐bridged chain‐like polymeric structure; triclinic, space group P$\bar 1$. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

(η⁶-Arene)ruthenium(II) complexes of the type [{[η⁶-C6H5(CH2)nCOOH]Ru(µ-Cl)Cl}2] (2a, n = 1; 3, n = 3) with tethered carboxylate groups can be obtained by dehydrogenation of the appropriate cyclohexadiene with RuCl3·3H2O. Formation of a κO-coordinated chelate in weakly acidic solution is observed by means of a ¹H NMR titration for both [{η⁶-C6H5(CH2)3COOH}Ru(aq)](OTf)2 (3a') and [{η⁶-C6H5(CH2)3COOH}Ru(phen)(aq)](OTf)2 (5'). Sandwich complexes of the type [{η⁶-C6H5(CH2)3COOH}Ru(η⁶-amino acid)](OTf)2 [amino acid = AcpheOH (6), ActyrOEt (7), ActrpOH (8)] can be prepared by treating [{η⁶-C6H5(CH2)3COOH}Ru(acetone)3](OTf)2 with the appropriate aromatic bioligand in CF3COOH (6/8) or CH2Cl2 (7). Chemospecific η⁶-labelling of the C-terminal indole function is observed for the peptide HphetrpOH in the analogous complex 9. Quantitative formation of 8 can also be achieved in aqueous solution in the presence of a 3:1 excess of the {η⁶-C6H5(CH2)3COOH}Ru^II fragment. This can also be employed for the N-terminal labelling of amino acids and peptides in its sandwich complex [(η⁶-C6Me6)Ru{η⁶-C6H5(CH2)3COOH}](OTf)2 (10). Coupling reactions by the carbodiimide method with EDC afford water-stable complexes of the type [(η⁶-C6Me6)Ru{η⁶-C6H5(CH2)3C(O)R}](OTf)2 [R = trpOMe (11), pheOMe (12), glyglyOEt (13)] in good yields. X-ray structures of [(η⁶-C6H5CH2COOC2H5)RuCl(phen)](OTf) (4b') and 10 are reported. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

CuX‐based coordination polymers (X = I, CN, SCN) with diazacrown ethers or cryptands as bridging ligands have been prepared by reaction of CuX with appropriate macrocycle in acetonnitrile/hexane solution at 100 °C. Whereas [CuI (1, 7‐DA12C4)] (1) and [CuI(1, 10‐DA18C6)] (2) (1, 7‐DA12C4 = 1, 7‐diaza‐12‐crown‐4, 1, 10‐DA18C6 = 1, 10‐diaza‐18‐crown‐6) are both monomeric, ∞1[(CuI)2(1, 10‐DA18C6)] (3) contains infinite chains in which (CuI)2rings are linked in a μ‐N1, N10manner by thiacrown ether moieties. The distorted tetrahedral coordination of the CuIatoms in 3is completed by a weak Cu…O interaction (2.393(7)Å) to a 1, 10‐DA18C6 oxygen atom. ∞2[(Cu4I4)(1, 10‐DAcrypt)2] (4), (1, 10DAcrypt = 1, 10‐diaza‐cryptand [2.2.2]), ∞2[{(CuCN)6(1, 7‐DA12C4)4]·2CH3CN (5) and ∞2[(CuSCN)2(1, 10‐DA18C6] (6) all exhibit lamellar networks with respectively Cu4I4cubes, (CuCN)6hexagons and ∞1[(CuSCN)2] double chains as their CuX substructures. 4can imbibe up to 0.64 mol KNO3/mol cryptand and 6up to 0.35 mol KNO3/mol 1, 10‐DA18C6 as a guest lattice. Crystal structures are reported for 1‐6, thermal analysis data (TG/DTA) for complexes 2, 3and 5.

The salicylhydrazone of anthranilhydrazide (H₂L) reacted with MoO₂(acac)₂ in refluxing alcohols to yield compounds of the general formula MoO₂L(ROH) (where R = CH₃, C₂H₅, n-C₃H₇, n-C₄H₉). The complex MoO₂L(C₂H₅OH) is found to undergo facile reaction with heterocyclic bases to form MoO₂L(Q)-type complexes where Q = pyridine, 4-picoline, imidazole and substituted imidazoles. Single crystal X-ray structural studies on the ligand H₂L (1) and the complexes MoO₂L(C₂H₅OH) (2) and MoO₂L(Imz) (3) indicate that the free ligand exists in its keto form, but in the two complexes 2 and 3 the ligand coordinates to the MoO₂2+ core through the enolate oxygen, the phenolate oxygen and the azomethine nitrogen. Reaction of MoO₂L(C₂H₅OH) with PPh₃ in CH₃CN under dry dinitrogen, in the absence and presence of bipy, produced MoIVOL (2a) (brown) and MoIVOL(bipy) (2b) (green) respectively along with Ph₃PO. This reaction is reminiscent of the oxotransfer reaction from the MoO₂+2 core of a molybdoenzyme to the substrate PPh₃. Complexes 2 and 3 crystallized in the P2₁/n and P2₁/c space groups respectively and for both of them Z = 4. The structures clearly show that 2 and 3 have distorted octahedral coordination environments in which the Mo–O(ethanol) bond of 2 and the Mo–N (imidazole) bond of 3 are significantly longer than is usually observed. This is indicative of the weak bonding of ethanol and imidazole to the MoO₂2+ core and points to the inherent weakness of the sixth coordination position of the coordination polyhedron of the MoO₂2+ core in MoO₂L(C₂H₅OH) and MoO₂L(Imz).

The DNA binding of cationic complexes of the type [(η6-arene)Ru(Aa)(dppz)] (CF₃SO₃)_n (arene = C₆H₆, Me₃C₆H₃, C₆Me₆; dppz = dipyrido[3,2-a:2',3'-c]phenazine; n = 1, Aa = AcH₋₁cysOH 4–6; n = 2, Aa = AcmetOH 7–9; n = 3, Aa = H₂metOMe 10–12) containing S-coordinated amino acids (HcysOH = l-cysteine, HmetOH = l-methionine) has been studied by UV-vis titration and 2D-NOESY. Stable intercalative binding is indicated for these complexes by their steady decrease in absorbance at maxima between 350 and 390 nm on titration with CT DNA and the bathochromic shifts of these absorption maxima. Taking 4–12 and the analogous (η6-C₆Me₆)RuII complexes of the tripeptides HglyglycysOH (n =1, 13) and HglyglymetOH (n = 2, 15; HglyOH = glycine) into account, typical DNA binding constant (K_b) ranges can be established for (η6-arene)RuII complexes: 5.3 × 104–1.6 × 105 M−1 for monocations, 6.3 × 105–9.9 × 105 M−1 for dications and 1.6 × 106–5.5 × 106 M−1 for trications. These K_b values clearly reflect a strengthening of electrostatic interactions with the negatively charged phosphodiester backbone of DNA as the total cation charge increases. A consistent trend to higher K_b values is also apparent for the coligand series C₆H₆ &lt; Me₃C₆H₃ &lt; C₆Me₆ with the relative increase being, in general, more pronounced for C₆H₆/Me₃C₆H₃ pairs. The strong electronic influence of the coligand on dppz intercalation is also reflected by marked increases ΔT_m of 18.2–18.5 °C in the CT DNA thermal denaturation temperature for di- and tri-cationic (η6-C₆Me₆)RuII complexes. Upfield 1H NMR chemical shifts and characteristic NOE cross peaks for the dppz protons of the 1 ∶ 1 complex formed between 9 and d(GTCGAC)₂ are consistent with a side-on intercalation adjacent to T₂ from the major groove.

The DNA binding of cationic complexes of the type [(η5-C₅Me₅)Ir(Aa)(dppz)](CF₃SO₃)_n (dppz = dipyrido[3,2-a:2',3'-c]phenazine; n = 1, Aa = AccysOH 7; n = 2, Aa = AcmetOMe 4, H₂cysOMe 8; n = 3, Aa = H₂metOMe 5) containing S-coordinated amino acids (HmetOH = methionine, HcysOH = cysteine) has been studied by UV-vis titration, 2D-NOESY and gel electrophoresis. The observed steady decrease in absorbance at maxima between 350 and 400 nm on UV-vis titration with CT DNA and the bathochromic shifts of these absorption maxima are consistent with stable intercalative DNA binding for these complexes. An increase in the binding constant K_b from 8.80(6) × 104 for the monocation of 7 through 2.30(4) × 105 and 7.04(5) × 105 for the dications of 8 and 4 to 2.62(3) × 106 M−1 for the 3+ cation of 5 clearly reflects the strengthening of the electrostatic interaction with the negatively charged phosphodiester backbone of DNA with increasing cation charge. Analogous values of 2.81(7) × 105 and 1.26(5) × 106 M−1 were obtained for the (η5-C₅Me₅)RhIII complexes 14 (n = 2, Aa = H₂cysOMe) and 13 (n = 3, Aa = H₂metOMe). Binding site sizes for the organometallic IrIII and RhIII complexes on CT DNA lie in the range 1.5–2.1 base pairs. NOE cross peaks for the 1 ∶ 1 complex formed between 5 and d(GTCGAC)₂ are consistent with intercalation adjacent to T₂ from the major groove. Complexes 4, 5 and [(η5-C₅Me₅)Ir(HglyglymetOH)(dppz)](CF₃SO₃)₂ 6 (HglyOH = glycine) cleave the supercoiled plasmid pBluescript II KS+, on irradiation for 30–180 s with a high pressure Hg lamp, to afford nicked circular and linear DNA forms. X-Ray structural analyses are reported for [(η5-C₅Me₅)IrCl(dppz)](CF₃SO₃) 3 and [(η5-C₅Me₅)Ir(9-Etgua)(phen)] (CF₃SO₃)₂ 16 (9-Etgua = 9-ethylguanine).

Addition of diphenylphosphane or phenylphosphane to methyl 1‐cyclohexenecarboxylate (1) under base catalysis, yields the novel tertiary or secondary phosphanes 2a, 3, or4acontaining cyclohexyl backbones with the carboxylic groups in the 2‐position. The carboxylated derivative of the borane adduct of tricyclohexylphosphane 5ais accessible by a related reaction using Cy2P(BH3)Li instead of Ph2PH or PhPH2. The complete analysis of the 1H NMR spectrum of 2ausing 2D NMR spectroscopy (H,H‐, C,H‐COSY NMR spectra, 13C‐INADEQUATE) reveals the bis(equatorial) position of the Ph2P and COOMe substituents. This is supported by the results of the X‐ray structural analysis of 2b(space group P21/c). On addition of Cy2P(BH3)Li to 1and subsequent hydrolysis, 5a, the first functionalized derivative of tricyclohexylphosphane is obtained. In contrast to 2b, the COOMe substituent in 5aoccupies the axial position, the bulky phosphanyl group being equatorial as indicated by the X‐ray structural analysis (space group P21). Molybdenum(0) and palladium(II) complexes of 2aand 2bhave been synthesized. The influence of the carboxylated cyclohexyl substituent on the electronic and steric parameters of 2aand 2bis discussed.

An approach for the synthesis of moenomycin A12C-glycoside partial structures is reported based on allyltin chemistry.

The circular dichroism (CD) of the in situ‐formed Rh2(OCOCF3)4complexes of sterically hindered, secondary lanostane alcohols was investigated. The main object of the present studies are derivatives of 3β‐, 7α‐, 7β‐, and 11β‐hydroxylanostanes with or without an additional functional group, e.g., double bond, oxo‐, hydroxy‐, or acetoxy groups. Up to five Cotton effects (CEs) can be found in the CD spectra of Rh‐complexes of these alcohols in the spectral range between 650–300 nm. Correlation of the CEs signs with the absolute stereochemistry at the carbon atom bearing the hydroxy group was investigated. The Rh‐complex with the 3β‐acetoxylanostan‐11β‐ol ligand was isolated in the crystalline form. Its polymeric structure, determined by the X‐ray method, shows the di‐Rh‐units linked by the axially ligating oxygen atoms of the hydroxy and acetoxy groups. In the latter case, the coordination takes place through the carbonyl oxygen. Chirality 13:313–321, 2001. © 2001 Wiley‐Liss, Inc.

Technological interest in the design of multifunctional microporous materials has stimulated recent research into the development of mild solventothermal techniques for the construction of lamellar and framework Main Group chalcogenidometalates. Reaction pathways from elemental or metal chalcogenide sources can be influenced by a variety of often interdependent factors of which counter cation size and charge, solvent polarity, pH and temperature are of paramount importance. As reviewed in this article, the presence of predominant solution species such as cyclic tripyramidal M₃S₆³⁻ (M = As or Sb) or edge-bridged ditetrahedral Sn₂E₆⁴⁻ anions (E = S or Se) as molecular building units and their participation in columnar substructures is characteristic for M₂S₃- and SnE₂-based anionic networks. Hierarchical topological relationships between individual members of structural families of the type A_xM_yE_z (A = alkali metal or alkylammonium cation) can be established that provide a detailed insight into probable multiple-step cation-directed self-assembly mechanisms. These findings enable the development of rational guidelines for the employment of suitable counter cations in controlling the condensation of small solution species into chains, sheets or frameworks, whose cavities reflect the spatial requirements of the structure-directing agent.

The nickel(II) complex 3containing a 14-membered macrocyclic triphosphine phosphinate ligand is obtained by regioselective oxidation of the crown phosphine nickel(II) complex 2cwith molecular oxygen. The X-ray structure of 3·H2O (space group P21/c) has been determined. Oxidation of the macrocyclic phosphinous acid nickel(II) complex 2a(P4donor set) with H2O2/HCl or Br2and subsequent demetallation affords the macrocyclic phosphinic acid 5. Reaction of its methylester 6with thionyl chloride and subsequent reduction with LiAlH4gives the novel macrocyclic PH functional tetradentate phosphine 8in high yields.

η⁵-Pentamethylcyclopentadienyliridium(III) and -rhodium(III) sandwich complexes of the type [(η⁵-Cp*)M(η⁶-aa)](CF3SO3)2 (M = Ir, Rh; 3–14) containing L-tyrosine, L-tryptophan and L-phenylalanine derivatives (aa) can be prepared by treatment of [(η⁵-Cp*)ML3] (CF3SO3)2 [L = thf, (CH3)2CO, CH3CN] with the appropriate bioligand in thf for N-protected compounds and in CF3COOH for α-amino acids with unprotected amino groups. Coordination to the Cp*M^III fragments stabilizes the ketonic form of the tyrosine aromatic side chains, leading to a marked enhancement in the acidity of the p-hydroxy function. The crystal structure of [Cp*Ir(ActyrOMe)] (CF3SO3)2 (3b, ActyrOMe = N-acetyltyrosine methyl ester) confirms a marked distortion towards an η⁵-oxohexadienyl coordination mode as may be gauged from the tilting of the p-OH plane C13/C14/C15 by no less than θ = 12.9° from that of the remaining ring atoms. Facial isomers are present in an effective 1:1 ratio for all tryptophan derivatives. Whereas the Cp*Ir^III sandwich complexes of aromatic α-amino acids are stable in polar solvents, rapid decay is observed for analogous Cp*Rh^III complexes of N-unprotected derivatives in polar solvents. Comparative nonrelativistic and relativistic all-electron density functional calculations on the cationic sandwich complexes [Cp*M(η⁶-C6H5Me)]ⁿ⁺ (n = 2, M = Ir, Rh; n = 1, M = Ru) confirm that all three metals bind more tightly to Cp* than to toluene as gauged by the respective force constants (k1 > k2). A much larger relativistic enhancement of k2 for M = Ir (279 vs 207 Nm^–1) could be responsible for the greater stability of Cp*Ir^III complexes in solution.

Treatment of A2CO3(A=K, Rb) with Sn and Se in an H2O/CH3OH mixture at 130°C affords reaction solutions from which respectively K4Sn4Se10·4.5H2O (1) and Rb4Sn4Se10·1.5H2O (2) can be isolated on cooling. 1 crystallizes in the rhombohedral space group R3with a=b=15.320(3) Å, c= 21.019(7) Å, Z=6, V=4272(2) Å3, 2 in the same space group with a=b=15.539(2) Å, c=21.373(4) Å, Z=6, V=4469.4(13) Å3. These isotypic phases contain lamellar 2∞[Sn4Se4−10] polyanions in which SnSe4−4and [Sn2Se6]4−molecular building units are corner-bridged into a 63net with 36-membered cavities of 1.3×1.4 nm cross-section. Cs4Sn4Se10·3.2H2O (3) can be prepared under similar mild solventothermal conditions. It crystallizes in the triclinic space group P1with a=7.235(1) Å, b=9.468(2) Å, c=11.235(2) Å, α=68.77(3)°, β=83.25(3)°, γ=84.53(3)°, Z=1, V=711.2(2) Å3. In contrast to the 2-dimensional anions of the same formula type in 1 and 2, the 2∞[Sn4Se4−10] polyanions of 3 consist of 1∞[SnSe2−3] ribbons that are corner-bridged through ditetrahedral [Sn2Se6]4−units into sheets with smaller 20-membered pores. The role of starting pH, cation size and temperature on the construction of lamellar selenidostannates(IV) are discussed.

Reaction of (Et4N)Cl with AS2S3and Na2S in acetonitrile at 110°C affords the polymeric thioarsenate(III) (Et4N)2As6S10in which the cyclic [As3S6]3-and chainlike [As3S7]5-trinuclear molecular building units are linked together through common sulphur atoms into infinite double chains. In contrast, reaction of the same starting materials at higher temperatures (180°C) in water leads to formation of a markedly denser phase (Et4N)2As8S13, whose thioarsenate(III) 1∞[As8S132-] anions exhibit a higher condensation grade. These likewise double chains are composed of cyclic [AS3S6]3-and dinuclear [As2Ss]4-units with shared ѱ-AsS3tetrahedra corners. Analogous treatment of (Et4N)Cl with As2Se3and Na2Se in acetonitrile (T =110°C) yields (Et4N)[SeAsSe7].

The polymeric compounds ∞1[{Cu2I2(C6H5CN)2[cyclo‐(CH3AsO)4]} · C6H5CN] (1) and ∞1[Cu6Br6(C6H5CN)4{cyclo‐(CH3AsO)4}] (2) may be prepared by reaction of the copper(I) halide with methylcycloarsoxane (CH3AsO)nin benzonitrile at 100 °C. 1contains four‐membered (CuI)2rings, 2tricyclic Cu6Br6units, that are connected through bridging (CH3AsO)4ligands into infinite chains. π–π Stacking of terminal C6H5CN ligands from parallel chains leads to the construction of porous frameworks, whose cavities are large enough in the case of 1to accommodate guest C6H5CN molecules. In the presence of CsI, the self‐assembly reaction of CuI with (CH3AsO)4in H2O–CH3OH–CH3CN (at 20 °C) or CH3CN (at 130 °C) affords [Cs(H2O)2][Cu3I4{cyclo‐(CH3AsO)4}2] · 0.5 CH3OH (3) and Cs[Cu3I4{cyclo‐(CH3AsO)4}2] (4), whose 1‐ and 2‐dimensional anionic coordination polymers are linked together through respectively [Cs{cyclo‐(CH3AsO)4‐κ4O}2]+and [Cs{Cu3I4‐κ4I}{cyclo‐(CH3AsO)4‐κ4O}] sandwiches.

Reaction of A2CO3(A = K, Rb) with Sn and Se in an H2O/CH3OH mixture at 115–130°C affords the isotypic selenidostannates(IV) A6Sn4Se11_. xH2O (A = K, x = 8) 1and 2whose discrete [Sn4Se11]6–anions each contain two corner‐bridged ditetrahedral [Sn2Se6]4–species. Similar reaction conditions with A = Cs afford Cs2Sn2Se5_. H2O (3a) and Cs2Sn2Se5(3b) in which such [Sn2Se6]4–building blocks are connected through common Se atoms into infinite 2∞[Sn2Se52–] chains. The 1∞[Sn3Se72–] ribbons of (Et4N)2Sn3Se7(4), formed by treating (Et4N)I with Sn and Se in methanol at 130°C, can be regarded as resulting from the condensation of 2∞[Sn2Se52–] chains with molecular [SnSe4]4–anions. The anions [Sn4Se11]6–, 1∞[Sn2Se52–], and 1∞[Sn3Se72–] represent the products of individual reaction steps on the potential condensation pathway of [Sn2Se6]4–to the lamellar selenidostannates(IV) 2∞[Sn4Se92–] or 2∞[Sn3Se72–].

The pH and time dependent reactions of [Pt(en)(H₂O)₂]²⁺ (en = H₂NCH₂CH₂NH₂) with the histidylmethionine peptides Hhis-gly-metH, Ac-his-gly-gly-metH [Ac = CH₃C(O)] and Ac-his-ala-ala-ala-metH (Hgly = glycine, Hala = L-alanine) at 313 K have been studied by ion-pairing reversed-phase HPLC and ¹H and ¹⁹⁵Pt NMR spectroscopy. Following initial anchoring of the [Pt(en)]²⁺ fragment on the thioether S in a κ²O,S complex, metallation of the neighbouring amide nitrogen is relatively rapid for all three peptides at pH &lt; 4. After reaching a concentration maximum within 10–50 h, the resulting κ²N '_met,S six-membered chelate slowly isomerizes to the thermodynamically preferred κ²N ¹,S macrochelate and in the case of the tetra- and penta-peptides to the less favoured κ²N ³,S complex as well. The speed of this reaction is significantly faster for the latter i + 4 spacing of the ligating residues, which brings the thioether S and imidazole donor atoms into close proximity for an α helix conformation. Although time dependent studies indicated that the macrochelates are formed at a comparable rate to the κ²N '_met,S complexes in alkaline solution, a clear thermodynamic preference for the smaller methionine chelate is apparent for the longer peptides.

The hexaethylcyclohexaarsoxane complexes [{M(CO)3}2{cyclo-(C2H5AsO)6}], M = Cr, Mo, W, 2-4 have been prepared by the reaction of (C2H5AsO)nwith the respective metal hexacarbonyl in toluene and characterized by their IR and NMR spectroscopic data. For 2 the molecular structure was established by X-ray structural analysis. The 12 atoms of the As6O6ring form a flattened cuboctahedron in which the 6 oxygen atoms lie in the central equatorial plane. Cr(CO)3groups are coordinated facially by the upper and lower three arsenic atoms. An approximately S6symmetry is displayed by the Cr2As6O6core. Average values of respectively 116.3 and 98.9° are observed for the As–O–As and O–As–O angles in the hexadentate ligand. The ΕΙ-MS and 1H NMR data for (C2H5AsO)nsuggest that this alkylcycloarsoxane is present in solution as a mixture of species including trimers and tetramers so that a metal assisted ring expansion is required for the formation of 2-4.

The stable ternary copper(II) complexes of ATP and ADP, [Cu(H2ATP)(phen)]2· 7 H2O (2) and [Cu4(HADP)2(bipy)4(H2O)2(NO3)2] · 2 NO3(3), have been isolated from aqueous solution at respective pH values of 2.8 and 4.0. Their structures have been established by single crystal X-ray diffraction. Tridentate coordination of each of the Cu atoms by ono α-, one β- and one γ-phosphate O atom of one ATP molecule is observed in 2. The binding Oαatoms occupy axial positions in a distorted octahedral geometry at Cu and the Cu- Oα interactions are weak. The other axial position is occupied by a γ-phosphate O atom of the second ATP molecule, leading to a dimeric structure. The basic structure of 3 is similar with, in this case, bidentate coordination of each of the central Cu atoms by one α- and one β-phosphate O atom of ono ADP molecule. In this case, however, the third terminal β-phosphate O atoms each bind a further Cu atom. All four Cu atoms in 3 display square pyramidal coordination. The structures of 2 and 3 are stabilised by intramolecular stacking of adenine and phenanthroline/bipyridyl systems. The significance of these structures as models for enzyme-metal ion-nucleoside polyphosphate complexes is discussed.

The structure of fulvoferruginin (1), a carotane derivative from cultures of Marasmius fulvoferrugineus, has been established by spectroscopic investigations and an X -ray structure analysis. 1 exhibits antibacterial, antifungal. and cytotoxic activities.

Compounds of the type R2PCH2PR2(R = PriO, Me2N) react with cis-LM(CO)4(L = Bicyclo[2,2,1]hepta-2,5-dien; M = Cr, Mo, W) complexes to yield cis-substituted [R2PCH2PR2]M(CO)4derivatives. The structure of the molybdenum compound, [(PriO)2PCH2P(OPri)2]Mo(CO)4, has been determined. Diphosphorus ligands of the type R2P(S)CH2PR2(R = F, PriO) are monodentate and form [R2P(S)CH2PR2]2Mo(CO)4complexes, whereas the compound (Me2N)2P(S)CH2P(NMe2)2acts as a bidentate ligand

The potentially curare-like silicon compounds 8a-8f wore synthesized and investigated with respect to their structure-activity relationships. The conformations of the com­pounds in the solid state and in solution were studied by X-ray diffraction analysis (8a-8e) and 1H NMR spectroscopy (8a-8f), respectively. The muscle relaxing properties of 8a-8f were investigated on the mouse. The observed structure-activity relationships are not in accordance with the classical “14 Å model” for neuromuscular blocking agents.

The iminovanadium (V) com pounds tC4H9N = V(NtC4H9-SiMe2-NHtC4H9)Cl2(3) and [VCl(μ-Cl)(NtC4H9)(NHtC4H9)(NH2tC4H9)]2have been prepared by reaction of Me2Si(NHtC4H9)2with VO(OC2H5)Cl2and VO(O tC3H7)Cl2, respectively. 3 was investigated by 1H , 51V NMR spectroscopy and X-ray diffraction analysis; the structure has been found to be a mononuclear vanadium complex with a distorted trigonal bipyramidal arrangement of the ligands.

Diethoxybilirubin diethyl ester crystallises triclinic P1 with a = 13.903(5), b = 17.211(7), c = 9.831(5) Å, α= 110.07(3), β = 111.22(3), γ = 69.04(3)°, Z = 2, Dx- 1.15 gcm-3. The two pyrromethene systems of the tetrapyrrole are orientated almost perpendicular to one another (interplanar angle = 91.5°). Considerable bond delocalisation is observed within the individual pyrromethene units, which contain intramolecular N-H···N hydrogen bonds of length 2.73 and 2.80 Å. Parallel stacking of the chromophores is not observed in the crystal lattice.

Structural fluxionality is apparent in the ¹H- and ³¹P-NMR spectra of compounds of the type [Ru(L)(MeCN)(triphos)](CF3SO3), 2−5, at 25°C, where L represents a diorganyldithiocarbamate or a heterocyclic κ²N,S coordinating thioamide. In contrast, complexes [Ru(Et2NCS2)(Y)(triphos)]ⁿ⁺ (6, n = 1, Y = CO; 7, n = 0, Y = CN⁻; 8, n = 0, Y = H⁻) are stereochemically rigid in solution at this temperature, indicating that MeCN dissociation must occur for the crowded octahedral coordination spheres of 2−5. Reaction of [Ru(MeCN)3(triphos)](CF3SO3)2, 1, with Na(Et2NCS2) at a 1:2 molar ratio yields [Ru(Et2NCS2-κ²S)(Et2NCS2-κS)(triphos)], 9, which slowly converts to [Ru(Et2NCS2-κ²S)2(triphosO-κ²P)], 10, on recrystallization from ethanol/acetone under air [triphosO is O=P(Ph)2CH2C(CH3)(CH2PPh2)2]. A similar κ³P→κ²P arm-off dissociation leads to the formation of [Ru(mpy-κ²N,S)2(triphosO-κ²P)] (13) and [Ru(mmim-κ²N,S)2(triphosO-κ²P)] (14) (Hmpy = 2-mercaptopyridine, Hmmim = 2-mercapto-1-methylimidazole). Crystal structures are reported for [Ru(mbt-κ²N,S)(MeCN)(triphos-κ³P)](CF3SO3) (4) (Hmbt = 2-mercaptobenzothiazole), [Ru(mpym-κ²N,S)(mpym-κS)(triphos-κ³P)] (11) (Hmpym = 2-mercaptopyrimidine) and 14, the latter of which is present as the OC-6-13 isomer.

Development of solventothermal methods in the intermediate-temperature (100–600°C) range has been motivated by current interest in the design of solid-state compounds with open framework structures. The preparation of nanoporous chalcogenidometalates by this technique is particularly promising, as a combination of the typical ion-exchanging and catalytic features of zeolite-like phases with the unique optoelectronic properties of transition metal and group 13–16 chalcogenides could afford novel multifunctional materials. Superheated strongly polarizing solvents such as water, methanol, and amines at temperatures in the range 110–200°C provide reaction conditions adequate to greatly enhance solubility, diffusion, and crystallization but still mild enough to leave molecular building blocks such as chains and rings intact to participate in the formation of polymeric anions. Such intermediate temperatures often allow the isolation of metastable solid-state compounds and thermodynamically stable phases that decompose at higher temperatures. The dimensionality and pore size of the anion network can be influenced by the choice of a suitable structure-directing alkali metal or alkyl-ammonium cation. Methanolothermal conditions have been found to be particularly suitable for the preparation of selenido- and telluridometalates, and have afforded a new class of very tellurium-rich alkali metal tellurides such as RbTe6and Cs3Te22. This article presents a comprehensive review of the application of mild solventothermal techniques to the preparation of heavier group 14–16 and transition metal chalcogenidometalates. Superheated solventssuch as water, methanol, and amines at temperatures in the range 110–220°C provide expedient polar reaction media for the designed construction of chalcogenide-based open-sheet and framework materials. Such conditions greatly enhance solubility, diffusion, and crystallization, but are still mild enough to leave molecular units such as chains and rings intact to participate in the self-assembly of zeolite-like structures. Methanolothermal techniques are particularly suitable for the preparation of Se- and Te-based frameworks.

Die in den letzten Jahren stark vorangetriebene Entwicklung von solvatothermalen Methoden im mittleren Temperaturbereich (100–600°C) war vor allem durch das aufkommende Interesse motiviert, Festkörper mit offenen Gerüststrukturen zu entwerfen. Eine sehr vielversprechendes Anwendungsgebiet in dieser Hinsicht ist die Herstellung von nanoporösen Chalkogenidometallaten. Eine Kombination der Ionenaustausch‐ und Katalysatoreigenschaften von zeolithartigen Verbindungen mit den bedeutenden optoelektronischen Eigenschaften von Chalkogeniden der Übergangsmetalle sowie der Elemente der Gruppen 13–16 kann auf diese Weise zur Synthese von neuartigen, multifunktionalen Materialien führen. Werden stark polarisierende Lösungsmittel wie Wasser, Methanol und einige Amine auf 110–200°C erhitzt, so kann dies häufig zu vorteilhaften Reaktionsbedingungen führen. Einerseits werden Eigenschaften wie die Löslichkeit und die Diffusion der Ausgangsverbindungen sowie das nachfolgende Kristallwachstum begünstigt, andererseits sind die Bedingungen aber immer noch so mild, daß molekulare Bausteine wie Ketten oder Ringe nicht zerstört werden und polymere Anionenstrukturen bilden können. Synthesen bei 100–600°C führen erwartungsgemäß oft zu metastabilen Festkörperphasen oder solchen, die zwar thermodynamisch stabil sind, sich bei höheren Temperaturen aber zersetzen. Die Dimensionalität der Anionenstruktur sowie die Porengröße innerhalb eines Netzes können entscheidend durch die Wahl eines strukturdirigierenden Alkalimetall‐ oder Alkylammonium‐Kations beeinflußt werden. Methanolothermale Bedingungen haben sich im Hinblick auf die Synthese neuer Selenido‐ und Telluridometallate als besonders geeignet erwiesen. So konnte unter anderem eine neue Klasse von tellurreichen Alkalimetalltelluriden mit Mitgliedern wie RbTe6und Cs3Te22zugänglich gemacht werden. Dieser Artikel liefert einen umfassenden Überblick über die jüngsten Anwendungen solvatothermaler Methoden zur Synthese von Chalkogenidometallaten der schwereren Hauptgruppenelemente der Gruppen 14–16 sowie von Übergangsmetallchalkogeniden. Überhitzte Lösungsmittelwie Wasser, Methanol oder Amine sind bei Temperaturen zwischen 110 und 220°C vorteilhafte Reaktionsmedien für den Aufbau von zeolithartigen Schicht‐ und Gerüststrukturen auf Chalkogenbasis. Solche Bedingungen begünstigen einerseits Löslichkeit, Diffusion und Kristallisation, sind andererseits aber auch schonend genug, um Bausteine wie Ketten oder Ringe für eine Beteiligung an der Selbstorganisation von zeolithartigen Strukturen intakt zu lassen. Methanolothermale Synthesetechniken sind besonders zur Herstellung selen‐ oder tellurhaltiger Netzwerke geeignet.

The reaction of But2AsCl with Na[W(CO)3Cp] in THF yields the metal arsine Cp(CO)3W−AsBut2(1), which is oxidized with elemental sulfur to the arsine sulfide Cp(CO)3W−AsBut2(S) (2). 2 is converted in refluxing pentane with loss of CO into Cp(CO)2W(η2-AsBut2S) (3). The chiral complex contains the novel dihapto-But2As−S ligand and exhibits dynamic behaviour (⊿G≠286 = 15.4 kcal/mol). Side-on coordination of the But2As−S ligand is proved by spectroscopic data and X-ray analysis. 3 crystallizes in the monoclinic space group P21/n with a = 12.141(2), b = 15.179(2), c = 19.558(2) Å, β = 99.61(2)°. The structure was refined to R = 0.051 for 4087 independent reflections.

Trichloro(purinium)zinc(II) (1) and dichloro-bis-(7-azaindole)zinc(II) (2) have been prepared from respectively 1:1 (in acid solution) and 2:1 aqueous solutions of the parent base and zinc(II) chloride. In the latter case the salt di-[7-azaindolium]zinc(II) tetrachloride (3) is isolated under acid conditions. The structures of 1-3 have been established by X-ray structural analyses. Zinc coordinates the purine nitrogen N(7) in 1 and N(3) of 7-azaindole in 2. N(l) is protonated in 1. The bond length distribution of the cations 3 suggests a significant contribution from a resonance form in which N(9) carries the positive charge