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This article belongs to the Special Issue Molecular Simulations Applications in Biochemistry and Molecular Biology., The solid-state structural analysis and docking studies of three adamantane-linked 1,2,4-triazole derivatives are presented. Crystal structure analyses revealed that compound 2 crystallizes in the triclinic P-1 space group, while compounds 1 and 3 crystallize in the same monoclinic P21/c space group. Since the only difference between them is the para substitution on the aryl group, the electronic nature of these NO2 and halogen groups seems to have no influence over the formation of the solid. However, a probable correlation with the size of the groups is not discarded due to the similar intermolecular disposition between the NO2/Cl substituted molecules. Despite the similarities, CE-B3LYP energy model calculations show that pairwise interaction energies vary between them, and therefore the total packing energy is affected. HOMO-LUMO calculated energies show that the NO2 group influences the reactivity properties characterizing the molecule as soft and with the best disposition to accept electrons. Further, in silico studies predicted that the compounds might be able to inhibit the 11β-HSD1 enzyme, which is implicated in obesity and diabetes. Self- and cross-docking experiments revealed that a number of non-native 11β-HSD1 inhibitors were able to accurately dock within the 11β-HSD1 X-ray structure 4C7J. The molecular docking of the adamantane-linked 1,2,4-triazoles have similar predicted binding affinity scores compared to the 4C7J native ligand 4YQ. However, they were unable to form interactions with key active site residues. Based on these docking results, a series of potentially improved compounds were designed using computer aided drug design tools. The docking results of the new compounds showed similar predicted 11β-HSD1 binding affinity scores as well as interactions to a known potent 11β-HSD1 inhibitor., This research was funded by the Deanship of Scientific Research at Princess Nourah bint Abdulrahman University through the Research Groups Program (Grant No. RGP-1442-0010-4).

This article belongs to the Special Issue Molecular Spectroscopy and Molecular Structure: Commemorative Issue in Honor of Professor Austin J. Barnes on Occasion of his 75th Birthday, In this report, we describe the structural characterization of three 2,4-disubstituted-dihydropyrimidine-5-carbonitrile derivatives, namely 2-{[(4-nitrophenyl)methyl]sulfanyl}-6-oxo-4-propyl-1,6-dihydropyrimidine-5-carbonitrile 1, 4-(2-methylpropyl)-2-{[(4-nitrophenyl)methyl]sulfanyl}-6-oxo-1,6-dihydropyrimidine-5-carbonitrile 2, and 2-[(2-ethoxyethyl)sulfanyl]-6-oxo-4-phenyl-1,6-dihydropyrimidine-5-carbonitrile monohydrate 3. An X-ray diffraction analysis revealed that these compounds were crystallized in the centrosymmetric space groups and adopt an L-shaped conformation. One of the compounds (3) crystallized with a water molecule. A cyclic motif (R22(8)) mediated by N–H···O hydrogen bond was formed in compounds 1 and 2, whereas the corresponding motif was not favorable, due to the water molecule, in compound 3. The crystal packing of these compounds was analyzed based on energy frameworks performed at the B3LYP/6-31G(d,p) level of theory. Various inter-contacts were characterized using the Hirshfeld surface and its associated 2D-fingerprint plots. Furthermore, a molecular docking simulation was carried out to assess the inhibitory potential of the title compounds against the human dihydrofolate reductase (DHFR) enzyme., This research was funded by the Deanship of Scientific Research at Princess Nourah bint Abdulrahman University through the Fast-track Research Funding Program.

We thank MICINN (CTQ2016-76829-R AEI/FEDER, UE, and MAT2016-78155-C2-1-R) for financial support. S. G-G. and R. M-M. acknowledge ERDP funding. C. C. expresses her gratitude to MICINN for the award of a “Ramon y Cajal” contract (RYC-2014-16021). We thank Servicios Cientifico Tecnicos, Universidad de Oviedo, for allocating measuring time on the NMR spectrometers. The authors gratefully acknowledge Prof Eduardo Rubio for his useful guidance towards the preparation of the manuscript.

The properties of pyrazole-based systems have been widely investigated due to their chelating ability with metallic ions as terminal ligands, bridging ligands and precursors for the design of several multi-nitrogen ligands for coordination, bioinorganic and organometallic chemistry [1], in order to build up new coordination polymeric networks and metal-organic frameworks. Additionally, they are well known for their spin-crossover behavior and their biological and medicinal properties as analgesic, anti-inflammatory agents [2], etc. As a contribution to what has been previously reported, we will be describing herein, for the first time, the magnetic properties and antimicrobial activity of a pyrazole-based copper complex [3]. Furthermore, the Hirshfeld surfaces and the 2D-figerprint graphics [4] allowing the understanding of the properties and the occurrence of each intermolecular contact around the studied complex molecules will be discussed exclusively in detail. References : [1] a) Montoya, V., Pons, J., Garcia-Anton, J., Solans, X., Font-Bardia, M. & Ros, J. (2007). Inorg. Chim. Acta. 360, 625–637. b) Itoh, T., Fuji, Y., Toda, T. (1996). Bull. Chem. Soc. Jpn. 69, 1265. c) Sun, Y. J., Cheng, P., Yan, S. P., Liao, D. Z., Jiang, Z. H., Shen, P. W. (2002). J. Coord. Chem. 55, 363. d) Lam, M. H. W., Tang, Y. -Y., Fung, K. -M., You, X.-Z., Wong, W.-T. (1997). Chem. Commun. 957. [2] a) Kahn, O., Martinez, C. J. (1998). Science. 279, 44-48. b) Olguin, J., Brooker, S. (2011). Coord. Chem. Rev. 255, 203-240. c) Gursoy, A., Demiryak, S., Capan, G., Erol, K. & Vural, K. (2000). Eur. J. Med. Chem. 35, 359–364. d) Lynch, D. E. & McClenaghan, I. (2005). Acta Cryst. E61, o2349–o2351. [3] Direm, A., Tursun, M., Parlak, C. & Benali-Cherif. N. (2015). J. Mol. Struct. 1093, 208–218. [4] a) Spackman, M. A. & Jayatilaka, D. (2009). Cryst. Eng. Comm., 11, 19–32. b) Spackman, M. A. & McKinnon, J. J. (2002). Cryst. Eng. Comm. 4, 378–392.

A novel complex was synthesized from Cu(II), nicotinamide and itaconic acid and is formulated as [Cu(C5H4O4)2(C6H6N2O)2(H2O)2·2(H2O)] (1). The compound was characterized by elemental analysis, FTIR spectroscopy, UV-Vis and single crystal X-ray diffraction. The complex crystallizes in the triclinic P-1 space group, with a = 7.5111(2) Å, b = 9.8529(3) Å, c = 10.5118(4) Å, α = 116.244(3)°, β = 90.291(3)°, γ = 103.335(3)°, V = 673.81(4) Å3, Z = 1.The octahedral geometry around the copper(II) ion is of the form CuN2O4 consisting of two molecules of nicotinamide acting as monodentate ligand through the nitrogen atoms, two molecules itaconate ligand and two coordinated water molecules each coordinating through the oxygen atoms. The structure of 1 showed infinite chains build up linking the molecules together via strong OH⋯O and NH⋯O intermolecular hydrogen bonds generating a two dimensional network sheet along c axis. The antimicrobial study of the synthesized complex 1 was investigated and showed higher antibacterial activity against all the organisms comparing with Copper(II) nicotinamide 2 and Copper(II) itaconate 3.

In this manuscript we report the synthesis and X-ray characterization of four Zn(II) complexes and three Cd(II) complexes with an asymmetrical hydrazone–pyridine based ligand {HL = 2-acetyl-pyridyl-isonicotinoylhydrazone (HAPIH)}; i.e. {[Zn(HL)2](NO3)2·H2O} (1), [Zn(HL)Br2] (2), [Zn(HL)I2] (3), [Zn(HL)(NCS)2] (4), [Cd(L)2] (5), {[Cd(HL)Br2]·CH3OH} (6) and {[Cd(HL)I2]·2CH3OH} (7). The Schiff base acts as a tridentate N2O-donor ligand through the oxygen, the imine and pyridine nitrogen atoms in all the complexes. In most complexes, the ligand is observed to coordinate as a zwitterion since the proton in the hydrazine group ([double bond, length as m-dash]N–NH–C[double bond, length as m-dash]O) shifted to the uncoordinated pyridine ring, except in 7. On the other hand, in 5 the ligand acts as a negatively charged species and is bound to the cadmium center in the enolic form ([double bond, length as m-dash]N–N[double bond, length as m-dash]C–O−). In complexes 2–4, 6 and 7, the coordination geometry around each metal center is distorted trigonal bipyramidal, with the coordination sphere of the metal completed by two halide or NCS anions. On the other hand, in homoleptic complexes 1 and 5, the metal, chelated by two tridentate Schiff base ligands, exhibits an octahedral geometry. In the crystal packing of all compounds, the pyridine rings favour π–π interactions among the symmetry related complexes. The noncovalent interactions among the complexes have been analyzed using Hirshfeld surface analysis and DFT calculations using Grimme's D3 dispersion correction to properly describe the π–π interactions., We are grateful to the University of Tabriz for generous financial support to this research. A. B. and A. F. acknowledge financial support from the Spanish Ministry of Economy and Competitiveness (MINECO) through projects CTQ2014-57393-C2-1-P and CONSOLIDER INGENIO 2010 CSD2010-00065 (FEDER funds).

Four coordination polymers with the formulas [Zn(L)(NO3)]n (1), {[Zn(L)(NO2)]·CH3OH}n (2), [Cd(L)(NO2)]n (3) and [Cd(L)(NO3)]n (4) {HL=2-benzolypyridine-isonicotinoylhydrazone (HBPIH)} have been synthesized and characterized by elemental analyses, FT-IR spectroscopy, 1H and 13C NMR and single crystal X-ray data diffraction. The L ligand acts as a negatively charged tetradentae N3O-donor in 1–3 and pentadentate ligand in 4. The Schiff base ligand coordinates to a metal center as N2O-donor and coordinates to adjacent metal center via its Para-Nitrogen of pyridlyl group in 1–3 leading to formation of one-dimensional, 1D, coordination polymer. The oxygen atom of the ligand L also coordinates to the third metal center as a bridging atom in 4 and forms a two-dimensional, 2D, coordination polymer. Metal centers are six coordinated with distorted octahedral geometry in 1–3 and seven coordinated with pentagonal bipyramid geometry in 4. The nitrate and nitrite groups act as asymmetric bidentate ligands in all complexes.

In the title N-Mannich bases, 3-(adamantan-1-yl)-4-(4-fluoro­phen­yl)-1-[(4-phenyl­piperazin-1-yl)meth­yl]-4,5-di­hydro-1H-1,2,4-triazole-5-thione (C29H34FN5S) (I), and 3-(adamantan-1-yl)-4-(4-fluoro­phen­yl)-1-{[4-(2-meth­oxyphen­yl)piperazin-1-yl]-meth­yl}-4,5-di­hydro-1H-1,2,4-triazole-5-thione (C30H36FN5OS) (II), fluoro­phenyl, adamantane and piperazine moieties are linked to a planar triazole ring. There is an additional phenyl ring on the piperazine ring in (I) and a meth­oxy­phenyl ring in (II). In compound (I), the fluoro­phenyl and phenyl rings are inclined to the triazole ring by 86.55 (13) and 60.52 (12)°, respectively, and the two aryl rings are inclined to one another by 66.37 (13)°. In compound (II), the corresponding dihedral angles are 83.35 (13), 71.38 (15) and 11.97 (16)°, respectively. The crystal structure of (I) shows pairs of C—H...F hydrogen bonds forming inversion dimers, while in the crystal of compound (II), in addition to the C—H...F hydrogen bonds that generate chains parallel to the b axis, there are C—H...π inter­actions present that link the chains to form layers parallel to the ab plane., Financial support from the Spanish Ministerio de Economía y Competitividad (MINECO-13-MAT2013–40950-R, MAT2016–78155-C2–1-R and FPI grant BES-2011–046948 to MSMA), Gobierno del Principado de Asturias (GRUPIN14– 060) and FEDER funding, is also gratefully acknowledged.

Three heterometallic Schiff-base complexes of Cu having Pr, Nd and Sm as the heteroatoms have been synthesized. The compounds have also been characterized by their IR spectra and CHN analysis. The single crystal structures of these compounds have been studied from the X-ray crystallographic data. To the best of our knowledge the article describes the possibility of application of these compounds in the field of species dependent anion sensing for the first time. Amongst a number of anionic species, certain sulphur species were found to have greater reactivity towards a Schiff-base complex as they can incur probable changes in the molecular complexity. The S2O82−and S2O32− species could modify the spectral features of the Schiff-base complex containing Nd as the heteroatom. This particular complex was found to exhibit changes in its absorbance and fluorescence spectral features upon interaction with the anionic species S2O82−and S2O32−. The results give a strong platform for the Schiff base complexes for their analytical applications.

et al., The synthesis of ethylenediamine-N,,N′’-di-S,,S-(2,2′’-dibenzyl)acetic acid (H2-S,,S-eddba) and its ethyl-, propyl-, butyl- esters (R2-S,,S-eddba) are reported here. The esters were used for synthesis of the corresponding platinum(IV) complexes, [PtCl4(R2-S,,S-eddba)]. The compounds were characterized by elemental analysis, infrared, 1H and 13C NMR spectroscopy. The structure of propyl ester of H2-S,,S-eddba was confirmed by single-crystal X-ray analysis. All [PtCl4(R2-S,,S-eddba)] complexes displayed significantly higher in vitro cytotoxicity in comparison to cisplatin., This work was supported by the Ministry of Education and Science of the Republic of Serbia, Projects No. 172016, 175069 and 172035.

The molecular and crystal structure of a norbornane derivative decorated with isoxazoline and methylpyrolidine-2,5-dione ring, C19H20N2O5, were determined and characterized by single crystal X-ray diffraction and spectroscopic methods. Details of the molecular geometry having six stereogenic centers reveal that there are two enantiomeric forms in the crystal structure of the compound, S- and R-enantiomer named with respect to the majority of chiral centers. The same type enantiomers are used as building blocks in formation of noncovalent helices by weak C-H⋯O and C-H⋯N type H-bonds. While S-enantiomers form P-helix, R-enantiomers take part in the formation of M-helix. The intertwined P- and M- helices, yielding from supramolecular chirality of the compound, are interconnected by weak C-H⋯O type H-bonds. Thus, mixed-handed noncovalent DNA mimicry of the compound contrary to natural pure-handed DNA forms is established. The presence of weak H-bonds allowing DNA mimicry of the compound in a noncovalent manner is verified by QTAIM and Hirshfeld surface analyses. To the best of our knowledge, norbornane derivative examined here is the first example of noncovalent DNA-mimetic based on an unnatural organic small molecule. The stability level of the H-bonded helices of the compound is comparable to those of helical peptide chains, approximately half of their stabilities., One of the authors HK is thankful to The Scientific and Technological Research Council of Turkey (TÜBÍTAK) for financial support. The work is supported by TÜBÍTAK, Grant (No. 112T636).

A samarium-mediated novel synthesis of enantiopure 4-amino-1,3-diols is carried out through a samarium-promoted aldol–Tishchenko reaction starting from chiral α′-amino-α-chloro ketones (derived from natural α-amino acids) and aldehydes. The process takes place with moderate levels of stereoselectivity and in high yields. A mechanism is proposed to explain these results while the absolute configuration and structure of the aldol–Tishchenko adducts were established by X-ray analysis. This method has also been utilized for the synthesis of enigmols, 1-deoxysphingoid base analogues.

An efficient reaction of the (2R,1′S)- or (2S,1′S)-N,N-bis(p-methoxybenzyl)-2-(1-aminoalkyl)epoxides, derived from α-amino acids, with boron trifluoride-phosphoric acid complex is described. This process affords highly elaborated enantiopure tricyclic α,β-enones in high yields, through an ipso-Friedel–Crafts/Michael addition cascade.

A catalytic chromium-mediated novel synthesis of iodocyclopropanecarboxamides is reported. This reaction can be carried out on aromatic (E)- or (Z)-α,β-unsaturated amides in which the C=C double bond is di- or trisubstituted. This process takes place with total stereospecificity and the new C—I stereogenic center is generated with high stereoselectivity. Some synthetic applications of the obtained iodocyclopropanecarboxamides are also reported. The structures of the iodocyclopropanes and derivatives were established by X-ray analysis.

The chemical preparation and stereoselective enzymatic desymmetrization of a series of prochiral 2-substituted-1,3-propanediamines have been carried out using Pseudomonas cepacia lipase as biocatalyst. Syntheses of novel optically active orthogonally protected di- or triamines have been achieved for the first time with different grade of enantiodiscrimination depending on the C-2 substitution of the propane-1,3-diamine fragment. Final monoselective deprotection reactions of (S)-3-allyl-2-tert-butyl-1-(9-fluorenylmethyl)propane-1,2,3-triyltriscarbamate have allowed us to obtain a panel of novel enantiomerically enriched disubstituted triamines, compounds of difficult access by conventional synthetic methods.

A convenient highly stereoselective synthesis of chloro- and bromocyclopropanamides from di- tri- or tetrasubstituted (E)- or (Z)-α,β-unsaturated amides with total or high stereoselectivity promoted by chromium dichloride or dibromide is described. The transformation of chlorocyclopropanamides into the corresponding ketones or amines is also reported. A mechanism to explain these transformations is proposed.

Pop-directed asymmetric deprotonation of benzylic amines using [n-BuLi/(-)-sparteine] provides an efficient method for the synthesis of chiral NC alpha and NC alpha,alpha' derivatives with total selectivity with respect to competing allylic and ortho lithiation. The method described herein offers a straightforward route of accessing chiral N-Pop-protected nitrogen heterocycles.

A novel chromium-promoted alkyl- and silyl cyclopropanation of (E)- or (Z)-alpha,beta-unsaturated amides in which the C-C double bond is di-, or trisubstituted is described. This process takes place with total stereospecificity, and the new stereogenic center is generated with high or total stereoselectivity. A mechanism is proposed to explain the cyclopropanation reaction.

The complex fac-[Mn(CNtBu)(CO)3{(PPh2)2C−SCN}] (2) reacts with thiocyanogen, affording the unstable derivative fac-[Mn(CNtBu)(CO)3{(PPh2)C(SCN)C(SSCN)N(PPh2)}] (3), as a result of the insertion of ...

High enantioselection is obtained in Michael additions of cyclic beta-ketoesters in the presence of lanthanium triflates and (S,S)-ip-pybox. Intermediates based on simultaneous coordination of the lanthanide to both (S,S)-ip-box and beta-ketoester (in keto and enolate forms) are detected by means of ESI mass spectrometry and NMR experiments, and a possible mechanism is proposed through theoretical calculations.

Complexes [Re(ONCMe2)(CO)3(bipy)] (1) and [Re(ONCMe2)(CO)3(phen)] (2), synthesized by reaction of the respective triflato precursors [Re(OTf)(CO)3(N-N)] (N-N = bipy, phen) with KONCMe2, feature O-bonded monodentate oximato ligands. Compound [Re(CO)3(phen)(HONCMe2)]BAr'4 (3), with a monodentate N-bonded oxime ligand, was prepared by reaction of [Re(OTf)(CO)3(phen)], HONCMe2, and NaBAr'4. Deprotonation of 3 afforded 2. The oximato complexes reacted with p-tolylisocyanate, p-tolylisothiocyanate, maleic anhydride, and tetracyanoethylene, affording the products of the insertion of the electrophile into the Re-O bond, compounds 4-7. One representative of each type of compound was fully characterized, including single-crystal X-ray diffraction. The reactions of 1 and 2 with dimethylacetylenedicarboxylate were found to involve first an insertion as the ones mentioned above but followed by incorporation of water, loss of acetone, and formation of the charge-separated neutral amido complexes 9 and 10. The structure of 9 and 10 was determined by X-ray diffraction, and key features of their electronic distribution were studied using a topological analysis of the electron density as obtained from the Fourier map.

The reaction of chiral (2R,1'S)- or (2S,1'S)-2-(1-aminoalkyl)epoxides, 1 or 2 with a variety of organolithium compounds to obtain the corresponding (alphaS,betaS)- or (alphaR,betaS)- beta-amino alcohols in enantiopure form is reported. In both cases, the opening of the oxirane ring at C-3 proceeded with total regioselectivity. Moreover, the ring opening of aminoepoxides 1 or 2 by hydride (utilizing LiAlH4) to obtain the corresponding (2S,3S)- or (2R,3S)-3-aminoalkan-2-ols is also described. The reaction of 1 or 2 with LiAlD4 in place of LiAlH4 gave the corresponding (2S,3S)- or (2R,3S)-3-amino-1-deuterioalkan-2-ols.

Treatment of fac-[Mn(CNR)(CO)3{(PMe2)2CH2}]ClO4 (1a R = Ph, 1b R = tBu) with KOH produced the cleavage of one of the P–C bonds of the coordinated dmpm ligand, resulting in the formation of phosphine–phosphinite complexes fac-[Mn(PMe2O)(CNR)(CO)3(PMe3)] (2a,b). Alkoxides such as NaOMe and NaOEt promoted similar processes in 1a,b, yielding fac-[Mn(CNR)(CO)3(PMe3)(PMe2OR′)]ClO4 (3a R = tBu, R′ = Me; 3b R = Ph, R′ = Me; 4a R = tBu, R′ = Et; 4b R = Ph, R′ = Et) derivatives. The phosphinite ligand in 2a,b can be sequentially protonated by addition of 0.5 and 1 equivalent of HBF4 leading to fac-[{Mn(CNR)(CO)3(PMe3)(PMe2O)}2H]BF4 (6a,b) and fac-[Mn(CNR)(CO)3(PMe3)(PMe2OH)]BF4 (5a,b), respectively.

Copper(II) complexes of N-benzothiazolesulfonamides (HL1=N-2-(4-methylphenylsulfamoyl)-6-nitro-benzothiazole, HL2=N-2-(phenylsulfamoyl)-6-chloro-benzothiazole, and HL3=N-2-(4-methylphenylsulfamoyl)-6-chloro-benzothiazole) with ammonia have been synthesized and characterized. The crystal structures of the [Cu(L1)2(NH3)2].2MeOH, [Cu(L2)2(NH3)2], and [Cu(L3)2(NH3)2] compounds have been determined. Compounds and present a distorted square planar geometry. In both compounds the metal ion is coordinated by two benzothiazole N atoms from two sulfonamidate anions and two NH3 molecules. Complex is distorted square-pyramidal. The Cu(II) ion is linked to the benzothiazole N and sulfonamidate O atoms of one of the ligands, the benzothiazole N of another sulfonamidate anion, and two ammonia N atoms. We have tested the superoxide dismutase (SOD)-like activity of the compounds and compared it with that of two dinuclear compounds [Cu2(L4)2(OCH3)2(NH3)2] and [Cu2(L4)2(OCH3)2(dmso)2] (HL4=N-2-(phenylsulfamoyl)-4-methyl-benzothiazole). In vitro indirect assays show that the dimeric complexes are better SOD mimics than the monomeric ones. We have also assayed the protective action provided by the compounds against reactive oxygen species over Deltasod1 mutant of Saccharomyces cerevisiae. In contrast to the in vitro results, the mononuclear compounds were more protective to SOD-deficient S. cerevisiae strains than the dinuclear complexes.

The reactions of the hydrido-triruthenium cluster complex [Ru3(mu-H)(mu3-kappa(2)-HNNMe2)(CO)9] (1; H2NNMe2 = 1,1-dimethylhydrazine) with alkynes that have alpha-hydrogen atoms give trinuclear derivatives containing edge-bridging allyl or face-capping alkenyl ligands. Under mild conditions (THF, 70 degrees C) the isolated products are as follows: [Ru3(mu3-kappa(2)-HNNMe2)(mu-kappa(3)-1-syn-Me-3-anti-EtC3H3)(mu-CO)2(CO)6] (2) and [Ru3(mu3-kappa(2)-HNNMe2)(mu-kappa(3)-1-syn-Me-3-syn-EtC3H3)(mu-CO)2(CO)6] (3) from 3-hexyne; [Ru3(mu3-kappa(2)-HNNMe2)(mu-kappa(3)-3-anti-PhC3H4)(mu-CO)2(CO)6] (4), [Ru3(mu3-kappa(2)-HNNMe2)(mu-kappa(2)-MeCCHPh)(mu-CO)2(CO)6] (5) and [Ru3(mu3-kappa(2)-HNNMe2)(mu3-kappa(2)-PhCCHMe)(mu-CO)2(CO)6] (6) from 1-phenyl-1-propyne; [Ru3(mu3-kappa(2)-HNNMe2)(mu-kappa(2)-3-anti-PrC3H4)(mu-CO)2(CO)6] (7), [Ru3(mu3-kappa(2)-HNNMe2)(mu3-kappa(2)-BuCCH2)(mu-CO)2(CO)6] (8), and [Ru3(mu3-kappa(2)-HNNMe2)(mu3-kappa(2)-HCCHBu)(mu-CO)2(CO)6] (9) from 1-hexyne; [Ru3(mu3-kappa(2)-HNNMe2)(mu3-kappa(2)-HOH2CCCH2)(mu-CO)2(CO)6] (10) from propargyl alcohol; and [Ru3(mu3-kappa(2)-HNNMe2)(mu3-kappa(2)-MeOCH2CCH2)(mu-CO)2(CO)6] (11) from 3-methoxy-1-propyne. The regioselectivity of these reactions depends upon the nature of the alkyne reagent, which affects considerably the kinetic barriers of important reaction steps and the stability of the final products. It has been established that the face-capped alkenyl derivatives are not precursors to the allyl products, which are formed via edge-bridged alkenyl intermediates. At higher temperature (toluene, 110 degrees C), the complexes that have allyl ligands with an anti substituent are isomerized into allyl derivatives with that substituent in the syn position, for example, 4 into [Ru3(mu3-kappa(2)-HNNMe2)(mu-kappa(3)-3-syn-PhC3H4)(mu-CO)2(CO)6] (14). The diene complex [Ru3(mu-H)(mu3-kappa(2)-HNNMe2)(mu-kappa(4)-trans-EtC4H5)(CO)7] (13) has been obtained from the thermolysis of compounds 2 and 7 at 110 degrees C (3 and [Ru3(mu3-kappa(2)-HNNMe2)(mu-kappa(2)-3-syn-PrC3H4)(mu-CO)2(CO)6] (12) are also formed in these reactions). A DFT theoretical study has allowed a comparison of the thermodynamic stabilities of isomeric compounds and has helped rationalize the experimental results. Mechanistic proposals for the synthesis of the allyl complexes and their isomerization processes are also provided.

Nine coordination compounds of Cu(II) and Co(II) with Ciprofloxacin (HCp) and Enoxacin (HEx) as ligands have been prepared and characterized. Single crystal structural determinations of [Cu(HCp)2(ClO4)2].6H2O (1) and [Co(HEx)2(Ex)]Cl.2CH(3)OH.12H2O (4) are reported. The crystal of 1 is composed of [Cu(HCp)2(ClO4)2] units with the two perchlorate anions semicoordinated, and uncoordinated water molecules. The copper ion, at a crystallographic inversion centre, is in a tetragonally distorted octahedral environment. The structure of 4 consists of cationic monomeric [Co(HEx)2(Ex)]+ units, chloride anions, and uncoordinated methanol and water molecules. The complex is six-coordinate, with a slightly distorted octahedral environment around the metal centre. Some complexes of ciprofloxacin and enoxacin were screened for their activity against several bacteria, showing activity similar to that of the corresponding free ligands. All compounds tested were more active against Gram-negative bacteria than against Gram-positive bacteria. Ciprofloxacin hydrochloride and its complexes were more active than enoxacin and its complexes. In addition, the bactericidal studies against Staphylococcus aureus ATCC 25923 reveal that one complex exhibits the "paradoxical effect" (diminution in the number of bacteria killed at high drug concentration), which has been described and related to the mechanism of action of quinolones, but three other complexes do not, suggesting different mechanisms of bactericidal action. The ability of Cu(HCp)2(NO3)2.6H2O to cleave DNA has been determined. The results show that the complex behaves as an efficient chemical nuclease with ascorbate/hydrogen peroxide activation. Mechanistic studies using different inhibiting reagents reveal that hydroxyl radicals are involved in the DNA scission process mediated by this compound.

The reactions of the 1,1-dimethylhydrazine-derived cluster [Ru 3 (μ-H)(μ 3 -η 2 -HNNMe 2 )(CO 9 ] with conjugated diynes, RC 4 R (R = Me, Ph), afford the ynenyl derivatives [Ru 3 (μ 3 -η 2 -HNNMe 2 )(μ-η 2 -RCCCCHR)(μ-CO) 2 (CO) 6 ] (R = Me) and [Ru 3 (μ 3 -η 2 -HNNMe 2 )(μ 3 -η 3 -RCCCCHR)-(μ-CO)(CO) 7 ] (R = Me, Ph), featuring η 2 -edge-bridging and η 3 -face-capping coordination modes for their ynenyl ligands. DFT calculations have revealed that the face-capped products are slightly more stable than the edge-bridged ones. The regioselectivity of the reactions is affected by the nature of the R groups of the diynes.

The reaction of the cluster complex [Ru 3 (μ-H)(μ 3 -η 2 -apyr)(CO) 9 ] (1; Hapyr = 2-aminopyrimidine) with 1,6-diphenoxy-2,4-hexadiyne in refluxing THF gives the trinuclear derivative [Ru 3 (η 3 -η 2 -apyr)(μ-η 3 -PhOCH 2 CH=CC≡CCH 2 OPh)(μ-CO) 2 (CO) 6 ] (2), which contains an edge-bridging ynenyl ligand. Heating 2 in refluxing toluene leads to an equilibrium mixture of compounds 2 and [Ru 3 (μ 3 -η 2 -apyr)(μ 3 -η 3 -PhOCH 2 CH=CC≡CCH 2 OPh)(CO) 8 ] (3), in which the ynenyl ligand is in a face-capping position. A mechanistic proposal that accounts for the interconversion of 2 and 3 has been obtained from DFT calculations, which have also revealed that isomer 2 is slightly more stable than 3 (3.5 kcal/mol). The bonding of the ynenyl ligands of 2 and 3 to their corresponding triruthenium frameworks has been studied by MO calculations.

The reactivity of the triruthenium cluster complex [Ru3(μ3-η3(C,N2)-Habq)(CO)9] (1; H2abqH = 2-amino-7,8-benzoquinoline) with alkynes, tetrafluoroboric acid, dihydrogen, and tertiary silanes and st...

The complex trans-[RuCl2{κ2-P,P-(S)-peap}2] (1) has been stereoselectively prepared by the treatment of a stoichiometric mixture of complex [RuCl2(DMSO)4] (DMSO = dimethyl sulfoxide) and (S)-peap [(S)-peap = (−)-N,N-bis(diphenylphosphanyl)-(S)-1-phenylethylamine] in refluxing toluene. Irradiation of a dichloromethane solution of 1 with a UV lamp (400 W) at −15 °C affords the complex cis-[RuCl2{κ2-P,P-(S)-peap}2] (2). The thermodynamically stable trans isomer 1 has also been obtained by heating complex 2 in toluene. The reaction of 1 with AgSbF6 in dichloromethane yields the complex [RuCl{κ2-P,P-(S)-peap}2][SbF6] (3), the first 16-electron cationic ruthenium complex bearing a four-membered chelate diphosphane ligand which has been fully characterized including its X-ray crystal structure. The reaction of unsaturated derivative 3 with CO gives the six-coordinate complex cis-[RuCl(CO){κ2-P,P-(S)-peap}2][SbF6] (4) in a stereoselective manner, which slowly transforms into trans-[RuCl(CO){κ2-P,P-(S)-peap}2][SbF6] (5) in a dichloromethane solution. The reaction of [RuCl{κ2-P,P-(S)-peap}2][BF4] with 1-phenyl-2-propyn-1-ol in 1,2-dichloroethane (60 °C) affords the allenylidene derivative trans-[RuCl(=C=C=CHPh){κ2-P,P-(S)-peap}2][BF4] (6). The cis-[Ru(acac){κ2-P,P-(S)-peap}2][SbF6] (7) is prepared by reaction of 3 and Na[acac]. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

The triruthenium cluster complexes [Ru3(I-H)(I3- 2 -HapyPh-N,N)(CO)9 ]( 1) and [Ru3(I‚)2(I3- 3 -HapyC6H4-N,N,C)2(CO)6 ]( 2) and the hexaruthenium ones [Ru6(I3-H)2(I5- 2 -apyPhN,N)(I-CO)2(CO)14 ]( 3) and [Ru6(I3-H)(I5- 3 -apyC6H4-N,N,C)(I-CO)3(CO)13 ]( 4) have been prepared from [Ru3(CO)12] and 2-amino-6-phenylpyridine (H2apyPh). Compound 1 contains a deprotonated HapyPh ligand capping a face of the metal triangle. Compound 2 contains two cyclometalated HapyC6H4 ligands, each spanning a Ru-Ru edge through the N atom of the amido fragment and chelating the remaining Ru atom through both the pyridine N atom and the C atom of the cyclometalated ring. The hexanuclear derivatives 3 and 4 have an uncommon basal edge-bridged square pyramidal metallic skeleton. The bridging ligand of 3 is a doubly deprotonated apyPh ligand which caps the metallic square through the exocyclic N atom, while is attached to the Ru atom that bridges the edge of the square pyramid through the pyridine N atom. Complex 4 is structurally related to 3 but has a cyclometalated phenyl ring. It has been established that compound 2 is formed by reaction of 1 with H2apyPh and that complex 3 is formed by reaction of 1 with [Ru3(CO)12]. While the hydrogenation of 4 gives 3, the thermolysis of 3 gives 4 among other unidentified products. The reaction of the osmium cluster [Os3(CO)10(MeCN)2] with H2apyPh gives a 1:5 mixture of the edge-bridged decacarbonyl derivatives [Os3(I-‚)(I- 1 -HapyPh-N)(CO)10 ]( 5) and [Os3(I-H)(I- 2 -HapyPhN,N)(CO)10 ]( 6). Both compounds give the face-capped nonacarbonyl derivative [Os3(I-H)(I3- 2 -HapyPh-N,N)(CO)9 ]( 7) upon irradiation with UV light. Curiously, while complexes 5 and 7 are stable in refluxing toluene, the thermolysis of 6 gives a mixture of 5, 7, and the cyclometalated dihydride [Os3(I-H)2(I- 3 -HapyC6H4-N,N,C)(CO)9 ]( 8).

The redox capabilities of some binuclear and trinuclear ruthenium complexes with bridging o-phenylendiamido ligands, C6H4(NH)2-o, have been investigated. The known species [Ru2{μ-C6H4(NH)2-o}(μ-dppm)(CO)2(PPh3)2] (1) and [Ru2Mo{μ-C6H4(NH)2-o}2(CO)6(PPh3)2] (5), reacted with [Fe(Cp)2](PF6), yield the salts [Ru2{μ-C6H4(NH)2-o}(μ-dppm)(CO)2(PPh3)2](PF6)2 (2) and [Ru2Mo{μ-C6H4(NH)2-o}2(CO)6(PPh3)2](PF6)2·CH2Cl2 (6), respectively (dppm = Ph2PCH2PPh2). Binuclear compounds analogous to 2 were obtained with pairs of PPh3 or CO ligands in place of the diphosphine dppm. The redox properties of the compounds have been explored also with electrochemical methods. The structural determinations of 2 and 6 show, as an evident consequence of the oxidation, the bending of the originally upright C6H4(NH)2-o bridge toward one metal that is eventually η4-coordinated by the ligand. In the trinuclear species 6, such a bending is limited to only one bridge and is directed toward the central molybdenum atom. Another structural co...

The sequential low-temperature addition reaction of an organolithium compound and methyl triflate to (menthyloxy)(3-furyl)carbene complexes of chromium and tungsten proceeded with excellent regioselectivity (1,4-addition) and diastereoselectivity (2,3-trans disposition of the nucleophile and electrophile groups) to afford new 2,3-disubstituted (2,3-dihydro-3-furyl)carbene complexes. In addition, a high degree of diastereofacial selectivity was achieved by employing alkenyllithium compounds. After detachment of both the metal fragment and the chiral auxiliary group, trisubstituted 2,3-dihydrofuran derivatives containing a quaternary stereogenic center at the C3 position were obtained. The characterization, including X-ray crystallography, of a novel type of stable four-membered chelate (eta(2)-alkene)tetracarbonylcarbene complex of chromium is also reported.

Treatment of [Ru3(CO)12] with bis(2-pyridyl) ketone oxime (Hdpko) in refluxing THF leads to a separable mixture of [Ru3(μ,η3-dpko-N,N,O)2(CO)8] (1) and [Ru2(μ,η3-dpko-N,N,O)2(CO)4] (2). In both complexes, two Ru atoms are doubly bridged by two dpko ligands, which are attached to a Ru atom through the oximate O atom while chelating the other Ru atom through the N atoms of a pyridyl group and the oximate fragment. While the Ru−Ru distance of the bridged edge of complex 1 is very long [3.5388(9) A], that of complex 2 is very short [2.620(1) A]. The acetonitrile complexes [M3(CO)10(MeCN)2] (M = Ru, Os) react with Hdpko in THF at room temperature to give [M3(μ-H)(μ,η3-dpko-N,N,O)(CO)9] [M = Ru (3) Os (4)], in which the dpko ligand behaves in the same way as in 1 and 2. The thermal reaction of 3 with Hdpko leads to a mixture of 1 and 2, while an analogous treatment of complex 4 gives [Os3(μ,η3-dpko-N,N,O)2(CO)8] (5), which is isostructural with complex 1. Compounds 1 and 3 are the first examples of ruthenium clusters containing oximate ligands. These oximate complexes display low activity as DNA cleavage agents, requiring high complex concentrations, long incubation times, and the use of UV light as a trigger. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Complexes [RuX(η3-2-C3H4R)(CO)(P⌒P)] (X = Cl, Br; R = H, Me; P⌒P = dppf, dippf) (2a−d and 3a−d) have been prepared by reaction of the η3-allylruthenium(II) derivatives [RuX(η3-2-C3H4R)(CO)3] (1a−d) with 1 equiv of the appropriate diphosphine. Treatment of 2a−d and 3a−d with HX allows the high-yield preparation of the dimeric compounds [{RuX(μ-X)(CO)(P⌒P)}2] (P⌒P = dppf, X = Cl (4a), Br (4b); P⌒P = dippf, X = Cl (5a), Br (5b)). Complex [{RuCl(μ-Cl)(CO)(dppf)}2] reacts with neutral ligands, via chloride bridge cleavage, affording the mononuclear derivatives [RuCl2(CO)(L)(dppf)] (L = CO (6a), BzNC (6b), Py (6c), PhNH2 (6d)). The structures of compounds [RuCl(η3-C3H5)(CO)(dppf)] (2a), [{RuCl(μ-Cl)(CO)(dppf)}2] (4a), and [RuCl2(CO)(Py)(dppf)] (6c) have been confirmed by X-ray crystallography. The catalytic activity of dimers 4a,b and 5a,b in transfer hydrogenation of ketones by propan-2-ol has also been studied.

The reaction of a two-fold molar excess of the potential N,O-donor ligand 2-(hydroxymethyl)-1-methylimidazole (Hmi) with trans-[ReOCl3(PPh3)2] led to the isolation of cis-[ReOCl2(mi)(PPh3)]. An X-ray structure determination indicated that the complex has distorted octahedral geometry, and that mi coordinates as a bidentate with the alcoholate oxygen trans to the oxo group. A similar reaction with 2-(1-ethyloxomethyl)-1-methylimidazole (eomi), the ethyl substituted analogue of Hmi, led to the formation of the oxo-bridged dinuclear complex [(μ-O){ReOCl2(eomi)2}2]. The ligand eomi coordinates as a monodentate via the imidazole nitrogen, with the "hard" ether oxygen uncoordinated. An X-ray crystal structure indicates that the chlorides are trans to each other in the ReN2Cl2 planes, which are orthogonal to the O=Re-O-Re=O backbone.

[{Ru(η6-p-cymene)(μ-Cl)Cl}2] and [{Ru(η3:η3-C10H16)(μ-Cl)Cl}2] react with Ph2PCH2P{NP(O)(OR)2}Ph2 (R = Et (1a), Ph (1b)) affording complexes [Ru(η6-p-cymene)Cl2(κ1-P-Ph2PCH2P{NP(O)(OR)2}Ph2)] (R = ...

Treatment of the methoxymethylidyne-bridged triruthenium cluster [Ru3(m-H)(m-COMe)(CO)10 ]( 1) with the symmetric diynes RC/CC/CR (R/Me, Ph, CH2OPh) led to separable mixtures of two regioisomers, [Ru3(m-H)(m3-h 3 -MeOCCR/CC/CR)(CO)9] and [Ru3(m-H)(m3-h 3 -MeOCC(C/CR)/CR)(CO)9]. These products arise from the insertion of one of the alkyne moieties of the corresponding diyne into a Ru/C bond of the methylidyne ligand. In all cases, the second alkyne functionality remains uncoordinated. In contrast, the reactions of the trihydride cluster [Ru3(m-H)3(m3-COMe)(CO)9 ]( 2) with diphenylbutadiyne led to a mixture of regioisomers in which one alkyne group of the original diyne has inserted into a Ru/C bond of the methylidyne ligand while the remaining triple bond has been hydrogenated to a double bond. The X-ray structures of the two regioisomers formed in the reaction of 1 with 2,4-hexadiyne are reported. # 2002 Elsevier Science B.V. All rights reserved.

The diphenylallenylidene complex [Ru(CCCPh 2 )(η 5 -C 9 H 7 )(PPh 3 ) 2 ][PF 6 ] ( 1 ) regioselectively reacts at the C γ atom with the lithium enolate derived from (1 R )-(+)-camphor to yield σ-alkynyl derivative [Ru{CCCPh 2 (C 10 H 15 O)}(η 5 -C 9 H 7 )(PPh 3 ) 2 ] ( 2 ). Complex 2 was obtained as a non-separable mixture of two diastereoisomers, i.e. (1 R ,3 S ,4 R )- 2 and (1 R ,3 R ,4 R )- 2 (ca. 3:2 ratio), in which the alkynyl fragment is located in exo or endo disposition on the camphor skeleton, respectively. Protonation of this mixture with HBF 4 ·Et 2 O affords the vinylidene derivative [Ru{CC(H)CPh 2 (C 10 H 15 O)}(η 5 -C 9 H 7 )(PPh 3 ) 2 ][BF 4 ] ( 3 ) as a single diastereoisomer, i.e. (1 R ,3 S ,4 R )- 3 , showing an exo disposition of the vinylidene group. The structure of complex (1 R ,3 S ,4 R )- 3 has been confirmed by X-ray diffraction. The molecular structure shows the typical pseudo-octahedral three-legged piano-stool geometry around the ruthenium atom, which is linked to the phosphorus atoms of the PPh 3 ligands, to the η 5 -bonded indenyl ligand, and to an almost linear vinylidene chain (RuC(1)C(2)=165.6 (18)°) with a RuC(1) bond length of 1.88 (2) A. Demetalation of (1 R ,3 S ,4 R )- 3 , by treatment with acetonitrile at reflux, yields the terminal alkyne HCCCPh 2 (C 10 H 15 O) ( 4 ) and the nitrile complex [Ru(NCMe)(η 5 -C 9 H 7 )(PPh 3 ) 2 ][BF 4 ] ( 5 ). Compound 4 was obtained as a non-separable mixture of two diastereoisomers, i.e. (1 R ,3 S ,4 R )- 4 and (1 R ,3 R ,4 R )- 4 (ca. 3:1 ratio). Related reactions starting from diphenylallenylidene 1 and the (1 S )-(−)-camphor enolate are also reported.

Treatment of [MoCl(eta(3)-allyl)(CO)(2)(phen)] with NaCN in CH2Cl2/MeOH afforded [Mo(CN)(eta(3)-allyl)(CO)(2)(phen)] [allyl = C3H5 (1a); 2-MeC3H4 (1b)] as the sole products (no products of cyanide attack on the allyl group were detected). Treatment of 1a,b with [Mo(OTf)(eta(3)-C3H5)(CO)(2)(phen)] and NaBAr'(4) in CH2Cl2 yielded the compounds [{Mo(eta(3)- allyl)(CO)(2)(phen)}(mu-CN){Mo(eta(3)-C3H5)(CO)(2)(phen)}]BAr'(4) (2a,b). Analogous treatment of 1a with fac-[M(OTf)(CO)(3)(bipy)] (M = Mn, Re) and NaBAr'(4) resulted in the synthesis of [{Mo(eta(3)-C3H5)(CO)(2)(phen)}(mu-CN){M(CO)(3)(bipy)}]BAr'(4) (3, 4), in which the C and N atoms of the cyano bridge are bonded to Mo and M (M = Mn, Re), respectively. The linkage isomer of 4 (C and N atoms of the cyano group bonded to Re and Me, respectively) (6) was prepared by treatment of [Re(CN)(CO)(3)(bipy)] (5) with [Mo(OTf)(eta(3)-C3H5)(CO)(2)(phen)] and NaBAr'(4). Compounds 1a, 2b, 3, and 6 were characterized by X-ray diffraction. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).

The reaction of [Os3(MeCN)2(CO)10] with 2,2‘-diamino-1,1‘-binaphthalene (H2binam) affords the coordinatively unsaturated trinuclear derivative [Os3(μ-H)(μ3-η2-Hbinam-N,C)(CO)9] (1), which contains ...

Copper(II) complexes of new N-benzothiazole sulfonamides (HL1= N-2-(benzothiazole)naphtalensulfonamide and HL2 = N-2-(6-chlorobenzothiazole)toluenesulfonamide) with ethylenediamine (en) and diethylenetriamine (dien) have been synthesized and characterised. The crystal structures of [Cu(dien)2](L1)2 (1) and [Cu(en)2(H2O)2](L2)2 (2) compounds have been determined. The metal centre adopts a “4+2” distorted octahedral environment in both complexes. Unusually, the sulfonamidate anions act as counterions. Spectroscopic properties are in good agreement with the crystal structures. The superoxide dismutase (SOD)-like activity of complex 2 has been tested. Kupfer(II)-Polyamin-Komplexe mit N-Benzothiazol-Sulfonamidaten als Gegenionen — Synthese, Kristallstrukturen und Eigenschaften von [Cu(dien)2](L1)2[HL1 = N-2-(Benzothiazol)naphthalinsulfonamid, dien = diethylentriamin] und [Cu(en)2(H2O)2](L2)2 [HL2 = N-2-(6-Chlorbenzothiazol)toluolsulfonamid, en = Ethylendiamin] — Superoxid-Dismutase-Aktivitat Kupfer(II)-Komplexe neuer N-Benzothiazol-Sulfonamide (HL1 = N-2-(Benzothiazol)naphthalinsulfonamid und HL2 = N-2-(6-Chlorbenzothiazoltoluolsulfonamid) mit Ethylendiamin (en) und Diethylentriamin (dien) wurden synthetisiert und charakterisiert. Die Kristallstrukturen von [Cu(dien)2](L1)2 (1) und [Cu(en)2(H2O)2](L2)2 (2) wurden ermittelt. Die Metallzentren weisen eine verzerrt oktaedrische „4+2”-Koordination auf. Ungewohnlich ist die Funktion der Sulfonamidat-Anionen als Gegenionen. Die spektroskopischen Eigenschaften sind in guter Ubereinstimmung mit den Kristallstrukturen. Die Superoxid-Dismutase-Aktivitat (SOD) von Komplex 2 wurde ermittelt.

Iminophosphorane-phosphines Ph2PCH2P{NP(S)(OR)2}Ph2 (R = Et 1a, Ph 1b) have been prepared by treatment of bis(diphenylphosphino)methane with an equimolar amount of thiophosphorylated azides (RO)2P(S)N3. Dimers [{Ru(η6-p-cymene)(μ-Cl)Cl}2] and [{Ru(η3:η3-C10H16)(μ-Cl)Cl}2] react with a two-fold excess of 1a,b yielding the neutral complexes [Ru(η6-p-cymene)Cl2(κ1-P-Ph2PCH2P{NP(S)(OR)2}Ph2)] (R = Et 2a, Ph 2b) and [Ru(η3:η3-C10H16)Cl2(κ1-P-Ph2PCH2P{NP(S)(OR)2}Ph2)] (R = Et 5a, Ph 5b), respectively. Treatment of 2a,b and 5a,b with one equivalent of AgSbF6 affords the cationic species [Ru(η6-p-cymene)Cl(κ2-P,S-Ph2PCH2P{NP(S)(OR)2}Ph2)][SbF6] (R = Et 3a, Ph 3b) and [Ru(η3:η3-C10H16)Cl(κ2-P,S-Ph2PCH2P{NP(S)(OR)2}Ph2)][SbF6] (R = Et 6a, Ph 6b), respectively. The structure of the cation of complex 6a has been confirmed by X-ray crystallography. The preference observed for the κ2-P,S- vs. κ2-P,N- coordination of 1a,b seems to be sterically controlled since theoretical calculations on the models [Ru(η6-C6H6)Cl(κ2-P,N-H2PCH2P{NP(S)(OH)2}H2)]+A and [Ru(η6-C6H6)Cl(κ2-P,S-H2PCH2P{NP(S)(OH)2}H2)]+B show that isomer A is ca. 5.0 kcal mol−1 more stable than B. Dicationic complexes [Ru(η6-p-cymene)(κ3-P,N,S-Ph2PCH2P{NP(S)(OR)2}Ph2)][SbF6]2 (R = Et 4a, Ph 4b) and [Ru(η3:η3-C10H16)(κ3-P,N,S-Ph2PCH2P{NP(S)(OR)2}Ph2)][SbF6]2 (R = Et 7a, Ph 7b) have been obtained by treating 2a,b and 5a,b, respectively, with two equivalents of AgSbF6. The reactivity of [Ru(η6-p-cymene)(κ3-P,N,S-Ph2PCH2P{NP(S)(OEt)2}Ph2)][SbF6]24a towards neutral and anionic ligands has been explored allowing the synthesis of complexes [Ru(η6-p-cymene)(L)(κ2-P,S-Ph2PCH2P{NP(S)(OEt)2}Ph2)][SbF6]2 (L = NCMe 8, PMe39, PMe2Ph 10, PMePh211) and [Ru(η6-p-cymene)X(κ2-P,S-Ph2PCH2P{NP(S)(OEt)2}Ph2)][SbF6] (X = Br 12, I 13, N314), respectively. The catalytic activity of complexes 2–7a,b in transfer hydrogenation of ketones by propan-2-ol has been also studied.

Copper(II) ternary complexes based on the novel benzothiazole- N-sulfonamides, HL1 ( N-2-(4-methylbenzothiazole)benzenesulfonamide) and HL2 ( N-2-(6-nitrobenzothiazole)naphthalenesulfonamide) ligands, and pyridine have been synthesized and characterized. Complexes [Cu(L1)(2)(py)(2)] (1). and [Cu(L2)(2)(py)(2)] (2). were chemically characterized and their structures determined by means of single crystal X-ray analysis. In both compounds the Cu(II) ion is coordinated to four N atoms in a nearly square planar arrangement. The Cu-N bond distances are similar to those of Cu(2)Zn(2)SOD. The SOD mimetic activity of the complexes was determined both in vitro and in vivo. For determining the SOD-like activity of the complexes in vivo, we have developed a new method based on the complexes' protective effect on a delta sod1mutant of Saccharomyces cerevisiae against free radicals generated by hydrogen peroxide and menadione as well as free radicals produced in the cellular respiration process. The results have shown that complex 1 presents a protective action against oxidative stress induced by menadione or H(2)O(2) and that both complexes 1 and 2 protect against free radicals generated in cellular respiration.

The crystal structure of the title complex has been determined by single X-ray diffraction methods and refined to an R-value of 0.0543. It crystallizes in the monoclinic P2 1 /a space group with a = 21.1231(9), b = 9.4523(4), c = 16.1874(7) A, β = 107.3706(3)° and Z = 4. The compound represents only the second known example of a simple mononuclear metal complex containing simultaneously N- and O-bonded saccharinato ligands. Its infrared spectrum and thermal behavior are also briefly discussed.

The reactivity of the neutral triruthenium carbonyl cluster [Ru3(m-H)(m3-HNNMe2)(CO)9 ]( 1) and its protonated derivative [Ru3(m-H)2(m3-HNNMe2)(CO)9][BF4 ]( 2), both containing a face-capping five-electron donor 1,1-dimethylhydrazido ligand, with an excess of triphenylphosphane and with bis(diphenylphosphanyl)methane (dppm) has been studied. With PPh3, compound 1 gives initially two independent monosubstituted isomeric intermediates that react with more ligand to afford [Ru3(m-H)2(m3HNNMe2)(C6H4PPh2)(PPh3)(CO)6] as the final product. This complex contains terminal and cyclometalated triphenylphosphane ligands attached to the same Ru atoms as the NMe2 and the NH fragments, respectively. The reaction of complex 2 with PPh3 affords, sequentially, the cationic mono-, di- and trisubstituted derivatives [Ru3(m-H)2(m3-HNNMe2)(PPh3)n (CO)9n ][BF4 ]( n/1/ 3). Unusually, the di- and trisubstituted complexes contain one PPh3 ligand in an axial position. The reaction of complex 1 with dppm gives the disubstituted derivative [Ru3(m-H)(m3-HNNMe2)(m-dppm)(CO)7], which contains the P atoms attached to the same Ru atoms as the NH fragment. Protonation of this complex with [HOEt2][BF4 ]g ives the cationic derivative [Ru3(m-H)2(m3HNNMe2)(m-dppm)(CO)7][BF4]. However, the reaction of complex 2 with dppm leads to an inseparable mixture of products. Many of these results contrast with those previously known for carbonyl substitution reactions on triruthenium clusters isostructural with compounds 1 and 2 but containing other face-capping five-electron donor ligands. The hardness of the donor atoms of the bridging ligand is presented as an important factor in relation to the observed regioselectivity. # 2002 Elsevier Science B.V. All rights reserved.

The ruthenium cluster complexes [Ru 3 (μ 3 -η 3 -abq-C,N,N)(CO) 9 ] (1) and [Ru 3 (μ-H) 2 (μ 3 -η 3 -abq-C,N,N) 2 (CO) 6 ] (2) (H 2 abq = 2-amino-7,8-benzoquinoline) have been stepwise prepared from [Ru 3 (CO) 1 0 (MeCN) 2 ]. Both compounds contain cyclometalated abq ligands which span a Ru-Ru edge through the N atom of an amido fragment and chelate the remaining Ru atom through both the quinolinic N atom and the C atom of the cyclometalated ring. For steric reasons, the cyclometalation is responsible for the observation of short Ru-N a m i d o bond lengths. The reaction of the osmium cluster [Os 3 (CO) 1 0 (MeCN) 2 ] with H 2 -abq gives the amido-bridged decacarbonyl derivative [Os 3 (μ-H)(μ-η 1 -Habq-N)(CO) 1 0 ] (3). Curiously, while complex 3 is stable in refluxing toluene, the ruthenium analogue of 3 has not been detected. Compounds 1-3 represent the first trinuclear carbonyl clusters containing ligands derived from 2-amino-7,8-benzoquinoline.

The reaction of the hydride complex [RuH(η5-C9H7)(κ2-P-dppm)] (1) with an excess of 1,4-diphenyl-1,3-butadiyne, PhC⋮C−C⋮CPh, yields complex [Ru{(E)-η1-C(C⋮CPh)CHPh}(η5-C9H7)(κ2-P-dppm)] (3), formed by regio- and stereoselective insertion of the alkyne into the Ru−H bond, in toluene or benzene-d6. The reaction, about 4 times slower than with the terminal alkyne phenylacetylene, proceeds via an associative mechanism, characterized by the following activation parameters: ΔH⧧ = 11 kcal mol-1; ΔS⧧ = −44 cal mol-1 K-1. The σ-enynyl complex 3 is protonated with an equimolar amount of HBF4·Et2O to give the cationic alkynylalkylidene complex [Ru{C(C⋮CPh)CH2Ph}(η5-C9H7)(κ2-P-dppm)][BF4] (4), which in turn is deprotonated by tBuOK to regenerate quantitatively complex 3. Both complexes 3 and 4 have been characterized by X-ray structural analysis. Complex 3 catalyzes the dimerization of PhC⋮CH to give (E)- and (Z)-1,4-diphenyl-1-buten-3-yne under milder conditions than analogous indenyl complexes [RuX(η5-C9H7)(dppm)]...

The reaction of [Ru3(CO)12] with levamisole hydrochloride ([Hlvms]Cl) leads to [Ru3(μ-Cl)(μ-η2-C11H13N2S-C,S)(CO)9] (1). This complex contains a new ligand that arises from an unprecedented oxidative addition of an S−C bond of protonated levamisole to a metal atom, and is the first example of a non-mononuclear complex derivative of levamisole. The mechanism of this reaction has been partially elucidated by studying the reaction of [Ru3(MeCN)2(CO)10] with [Hlvms]Cl and [Ru3(μ-Cl)(CO)10]− with [Hlvms][BF4]. It is concluded that upon treatment with levamisole hydrochloride, [Ru3(CO)12] is attacked by the chloride anion to give [Ru3(μ-Cl)(CO)10]−; a subsequent coupling of this cluster anion with the [Hlvms]+ cation leads to an uncharacterized neutral derivative which has an intact [Hlvms] group attached to a ruthenium atom through the sulfur atom. This neutral derivative readily undergoes an S−C bond activation process to give compound 1. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

A singular hydrazonato complex of palladium has induced the unexpected orthometallation of acetophenonephenylhydrazone on the phenyl group. This is the first X-ray characterized example of an orthopalladated E-arylhydrazone of general formula ArC(R″)NNHAr′ where the metallated aryl is Ar′ although palladation on Ar is not hindered. Structural evidence suggests that the PdN(amido) bond that is present in the starting material induced the palladation of the unexpected phenyl.