A Study on Some Copper (II) Complexes of Polyaza Cryptands and Planar Macrocycles—Synthesis,Characterization and Superoxide Dismutase Activity

Two kinds of macrocyclic copper(II) complexes were synthesized. One of them is composed of copper(II) cryptates of ligands L¹‐L⁴ which are condensation products of 5‐R‐2‐methoxy‐1,3‐phenyldialdehyde (R=OCH₃, L¹) with tris(2‐aminoethyl) amine and 5‐R‐2‐methothoxy‐1, 3‐phenyldialdehyde (R= CH₃, L³) with tris(2‐aminopropyl)amine as well as their reduced products of L¹ and L³ (L² and L⁴). The other is composed of two‐dimensional macrocyclic copper(II) complexes of ligands L⁵‐L⁸ of condensation products of diethylene triamine with 4‐R‐l‐methoxy‐2,6‐phenyldialdehyde (R= Cl, Br. CH₃, OCH₃). The relationship between their structures and superoxide dismutase (SOD) activity was investigated. The results can provide some clues to the synthesis of SOD mimics.     

Organoselenium/Tellurium-Bearing Macroacyclic and Cyclic Ligand Systems and Their Complexation Reactions

Abstract

A series of phenol-substituted acyclic Schiff bases, 2,6-{RE(CH₂) _n N═C(CH₃)}₂-C₆H₂(4-CH₃)(OH), (E = Te: R = C₆H₅, n = 2(L _a), 3(L _b); R = C₆H₄-4-OCH₃, n = 2(L _c), 3(L _d); E = Se: R = C₆H₅, n = 2(L _e), 3(L _f)), of the type E₂N₂O have been synthesized by condensation of 2,6-diacetyl-4-methylphenol with arylchalcogenoalkylamines. This ligand framework is useful for designing molecular complexes with a variety of coordination modes depending upon the nature of the central metal atom. The reactivity of the tellurium-bearing macroacyclics ligands towards Zn(II), Cd(II), and Hg(II) has been examined. The ligands L _a?L _d with Zn(II) and Cd(II), and only L _a and L _b with Hg(II) form complexes of composition M₂X₄L, (X = Cl or Br), whereas L _c and L _d with Hg(II) give products of composition HgBr₂L. The modes of ligand interaction with Zn(II) and Cd(II) are different than that with Hg(II).

Following a multistep reaction involving abstraction of bridged Br atoms and subsequent addition of more ligand, the mercury complex, Hg₂Br₄L has been used for developing metallocyclic system of the type [Hg₂Br₂L₂]²⁺. The latter has been found to encapsulate Zn(II) and Cd(II) to give multimetallic systems.     

Synthesis and Structures of Gallium‐β‐Diketiminate Complexes: Isolation of a Dinuclear Gallium(II) Complex

The sterically demanding β‐diketiminate ligand L^dmp [L^dmp = HC{(CMe)N(dmp)}₂, dmp = C₆H₃‐2,6‐Me₂] was used to stabilize various gallium complexes in the formal oxidation states +II and +III. The reaction of in situ generated [L^dmpLi] with gallium chloride affords [L^dmpGaCl₂] ( 1 ), which was used as starting complex to synthesize a variety of gallium(III) compounds [L^dmpGaX₂] [X = F ( 2 ), I ( 3 ), H ( 4 ), and Me ( 5 )]. Synthesis of the dinuclear complex [L^dmpGaI]₂ ( 6 ), with gallium in the formal oxidation state +II was accomplished by converting “GaI” with in situ generated [L^dmpLi] in toluene. All compounds were characterized by elemental analyses, NMR spectroscopy, LIFDI‐TOF‐MS, and single‐crystal X‐ray diffraction. Additionally DFT calculations were performed for analysis of the bonding in 6 .     

Darstellung und spektroskopische Charakterisierung von Kupfer(II)- und Nickel(II)-tricyanmethanid-Komplexen mit Imidazol-Derivaten – Kristallstruktur von [Cu{C(CN)3}2(2-meiz)2]

Synthesis and Spectroscopic Characterization of Copper(II) and Nickel(II) Tricyanomethanide Complexes with Imidazoles – Crystal Structure of [Cu{C(CN)₃}₂(2-meiz)₂] The copper(II) and nickel(II) tricyanomethanide complexes with imidazoles of the type [Cu{C(CN)₃}₂L₄], [L = 2- or 4-methylimidazole (meiz)] and [M{C(CN)₃}₂L₂] [M = Cu, L = imidazole (iz), 2- or 4-meiz; M = Ni, L = iz, 2- or 4-meiz] were prepared and characterized by electronic, infrared, and – some of them – by ESR spectroscopy. The structure [Cu{C(CN)₃}₂(2-meiz)₂], solved by X-ray crystallographic analysis, shows a two-dimensional network with unsymmetric C(CN)₃-bridges between the Cu^II atoms. Polymeric structures with bridging C(CN)₃-groups were identified by means of spectroscopic methods also for the other [M{C(CN)₃}₂L₂] complexes. On the other hand, for the complexes [M{C(CN)₃}₂L₄] follow molecular structures, in which monodentate C(CN)₃ ligands are present. All compounds under investigation show a tetragonal-bipyramidal geometry with various degree of tetragonal distortion.     

Platinum(II) Mixed Ligand Complexes with Thiourea Derivatives,Dimethyl Sulphoxide and Chloride: Syntheses,Molecular Structures,and ESCA Data

The platinum(II) mixed ligand complexes [PtCl(L^1‐6)(dmso)] with six differently substituted thiourea derivatives HL, R₂NC(S)NHC(O)R′ (R = Et, R′ = p‐O₂N‐Ph: HL¹; R = Ph, R′ = p‐O₂N‐Ph: HL²; R = R′ = Ph: HL³; R = Et, R′ = o‐Cl‐Ph: HL⁴; R₂N = EtOC(O)N(CH₂CH₂)₂N, R′ = Ph: HL⁵) and Et₂NC(S)N=CNH‐1‐Naph (HL⁶), as well as the bis(benzoylthioureato‐κO, κS)‐platinum(II) complexes [Pt(L^{1, 2})₂] have been synthesized and characterized by elemental analysis, IR, FAB(+)‐MS, ¹H‐NMR, ¹³C‐NMR, as well as X‐ray structure analysis ([PtCl(L¹)(dmso)] and [PtCl(L^{3, 4})(dmso)]) and ESCA ([PtCl(L^{1, 2})(dmso)] and [Pt(L^{1, 2})₂]). The mixed ligand complexes [PtCl(L)(dmso)] have a nearly square‐planar coordination at the platinum atoms. After deprotonation, the thiourea derivatives coordinate bidentately via O and S, DMSO bonds monodentately to the Pt^II atom via S atom in a cis arrangement with respect to the thiocarbonyl sulphur atom. The Pt—S‐bonds to the DMSO are significant shorter than those to the thiocarbonyl‐S atom. In comparison with the unsubstituted case, electron withdrawing substituents at the phenyl group of the benzoyl moiety of the thioureate (p‐NO₂, o‐Cl) cause a significant elongation of the Pt—S(dmso)‐bond trans arranged to the benzoyl‐O—Pt‐bond. The ESCA data confirm the found coordination and bonding conditions. The Pt 4f_7/2 electron binding energies of the complexes [PtCl(L^{1, 2})(dmso)] are higher than those of the bis(benzoylthioureato)‐complexes [Pt(L^{1, 2})₂]. This may indicate a withdrawal of electron density from platinum(II) caused by the DMSO ligands.     

Synthesis of (2-hydroxo-5-chlorophenylaminoisonitrosoacetyl)phenyl ligands and their complexes: Spectral,thermal and solvent-extraction studies

Four different types of new ligands Ar[COC(NOH)R] _n (Ar=biphenyl, n = 1 H₂L¹; Ar=biphenyl, n = 2 H₄L²; Ar=diphenylmethane, n = 1 H₂L³; Ar=diphenylmethane, n = 2 H₄L⁴; R=2-amino-4-chlorophenol in all ligands) have been obtained from 1 equivalent of chloroketooximes Ar[COC(NOH)Cl] _n (HL¹-H₂L⁴) and 1 equivalent of 2-amino-4-chlorophenol (for H₂L¹ and H₂L³) or 2 equivalent of 2-amino-4-chlorophenol (for H₄L² and H₄L⁴). (Mononuclear or binuclear cobalt(II), nickel(II), copper(II) and zinc(II) complexes were synthesized with these ligands.) These compounds have been characterized by elemental analyses, AAS, infra-red spectra and magnetic susceptibility measurements. The ligands have been further characterized by ¹H NMR. The results suggest that the dinuclear complexes of H₂L¹ and H₂L³ have a metal:ligand ratio of 1:2; the mononuclear complexes of H₄L² and H₄L⁴ have a metal:ligand ratio of 1:1 and dinuclear complexes H₄L² and H₄L⁴ have a metal:ligand ratio of 2:1. The binding properties of the ligands towards selected transition metal ions (Mn^II, Co^II, Ni^II, Cu^II, Zn^II, Pb^II, Cd^II, Hg^II) have been established by extraction experiments. The ligands show strong binding ability towards mercury(II) ion. In addition, the thermal decomposition of some complexes is studied in nitrogen atmosphere.     

Chemistry of platinum hydrides : XXV. Preparation and characterization of platinum(II) hydridotin complexes containing bulky phosphines

Platinum(II) hydridotin complexes containing bulky phosphine ligands, trans-Pt(H)L₂(SnR₃) have been prepared from: (i) the equimolar reaction between corresponding platinum(II) dihydride complexes and HSnR₃ (Cy = cyclohexyl), P-i-Pr₃, P-t-BuPh₂, P-t-Bu₂Me; R = Ph), (ii) the oxidative addition of the corresponding zerovalent complexes, Pt⁰L₂, with HSnR₃ (L = P-i-Pr₃, P-t-BuPh₂; R = Ph), (iii) the reaction of the corresponding platinum(II) dihydride complexes with ClSnR₃ in the presence of pyridine in benzene (L = P-i-Pr₃, P-t-BuPh₂; R = CH₃, n-Bu), (iv) the sodium borohydride reduction of the corresponding hydridochloride complexes Pt(H)Cl(PR₃)₂ with ClSnR₃ in THF (L = PCy₃; R = Ph), these compounds have been characterized by their elemental analysis, infrared, ¹H and ³¹P NMR spectral data.     

In vitro antifungal and antibacterial properties of thiodiamine transition metal complexes

Synthesis, characterization and biological studies of some thiodiamine metal complexes are described. Cobalt(II) and copper(II) complexes of type [Cu(L)₂Cl₂] and [Co(L)₂SO₄], where L = (cyclohexyl-N-thio)-1,2-ethylenediamine (L¹) and (cyclohexyl-N-thio)-1,3-propanediamine (L²), were synthesized. The synthesized copper and cobalt thiodiamine complexes were characterized by elemental analysis, IR, mass, UV-VIS and ¹H NMR spectroscopic studies. Thiodiamines coordinate as a bidentate N-S ligand. The binding sites are azomethine nitrogen and thioamide sulfur. Molar conductance values in dimethylsulfoxide indicate non-electrolyte nature of the complexes. In vitro-antimicrobial screening shows promising results against both bacterial and fungal strains.     

Structures of Metal Complexes with Anions of Di(hydroxymethyl)phosphinic and Di(chloromethyl)phosphinic Acids

This paper considers the structural features of complexes containing Ag(I), 3dmetals (Cu and Ni), and rare-earth elements (REE) such as La, Nd, Er, and Lu, alkaline-earth (Sr) or alkaline (Li, Na) metals with anions of di(hydroxymethyl)phosphinic (L¹) or di(chloromethyl)phosphinic (L²) acids with a general formula RR"PO^– ₂, where R = R" = OH and Cl for L¹and L², respectively. Different patterns of coordination between organophosphorus acids and different metals (four for each L¹and L²) are described. Structures of copper(II) complexes with L¹and L²were compared with those of Cu(II) with dialkyl- and diaryl-substituted monophosphonic and aminophosphinic acids.     

Complexes of osmium with tertiary arsines and carbonmonoxide

Osmium halides (Cl and Br) react with monotertiary arsines Ph₂RAs (R=Me, Et, Pr and Bu) in alcoholic medium to give paramagnetic octahedral complexes of the type OsX₃L₃ (X=Cl, Br; L=Ph₂RAs) which further react with carbonmonoxide to give dihalo dicarbonyl complexes of osmium(II) of the type OsX₂ (CO)₂ L₂. Similarly, osmium halides react with tertiary arsines in the presence of formaldehyde to give monocarbonyl complexes of osmium(II) of the type OsX₂ (CO)L₃. Structures have been assigned to all these compounds on the basis of IR and NMR studies.     

Synthesis and structural features of 1,3,2,5-dioxaboraphosphorinane complexes with Pt(II) and Pd(II) salts

Complexes of composition L₂MCl₂ [M=Pt, R=H (I), Me (II), Ph (III)], and LMC1₂ [M=Pd, R=H (IV)] are prepared by reaction of 4,6-R₂-2,5-diphenyl-1,3,2,5-dioxaboraphosphorinanes (L) with MCl₂. Far-IR and³¹P NMR spectroscopy are used to demonstrate that I is cis whereas II and III are trans complexes in the solid. The conformational behavior of I is studied by³¹P and¹H NMR. The asymmetric form of I exhibits anomalous stability.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2309–2312, October, 1991.     

Isomere η2-Acyl- und σ-Alkyl(carbonyl)-Komplexe von Molybdän und Wolfram. Eine Studie zum Bildungs-mechanismus,zur Isomerisierungsgeschwindigkeit und zur Steuerung der Gleichgewichtslage

η²-Acyl and σ-Alkyl(carbonyl) Coordination in Molybdenum and Tungsten Complexes: Synthesis and Studies of the Isomerization Equilibria and Kinetics The anionic molybdenum and tungsten complexes [L_RM(CO)₃]^? (L_R^? = [(C₅H₅)Co{P(O)R₂}₃]^?, R = OCH₃, OC₂H₅, O-i-C₃H₇; M = Mo, W) have been alkylated with the iodides R′ I, R′ = CH₃, C₂H₅, i-C₃H₇, and CH₂C₆H₅. The reactivity pattern of the alkylation is in accord with a S_N2 mechanism. Depending on M, R′, reaction temperature, and time the η-alkyl (carbonyl) compounds [L_RM(CO)₃R′] and/or the isomeric η²-acyl compounds [L_RM(CO)₂(η²-COR′)] can be obtained. 8 new σ-alkyl(carbonyl) compounds and 15 new η²-acyl compounds have been isolated and characterized. The ¹H NMR and the IR spectra give conclusive evidence that the σ-alkyl(carbonyl) compounds [L_RM(CO)₃R′] are formed as the primary products of the alkylation and that they isomerize partly or completely to give the η²-acyl compounds [L_RM(CO)₂(η²-COR′)]. The position of the equilibrium σ-alkyl(carbonyl)/η²-acyl is controlled by the steric demands of the groups R′ and the ligands L_R^?. The molybdenum compounds isomerize much more readily than the tungsten compounds. The rate constants of the isomerization processes [L_RMo(CO)₃CH₃] → [L_RMo(CO)₂(η²-COCH₃)], R = OCH₃, OC₂H₅, and O-i-C₃H₇, measured at 305 K in acetone-d₆, are 6–8 x 10^?3 s^?1.     

Preparation of Complexes of Nickel(II) Aryl Carboxylates with Morpholine and Piperidine

Complexes of nickel(II) aryl carboxylates with a general formula Ni(RC₆H₄COO)₂L₂ where R=H, p-CH₃. p-Cl, m- & p-NO₂; and L = morpholine and piperidine; have been prepared by the interaction of nickel(II) aryl carboxylates with a large excess of appropriate amine. Unlike parent anhydrous nickel(II) aryl carboxylates all these complexes are soluble in common organic solvents.     

Potentiometric and antimicrobial studies on the asymmetric Schiff bases and their binuclear Ni(II) and Fe(III) complexes; synthesis and characterization of the complexes

The protonation constants of two nitro-Schiff bases SB¹, SB² and three asymmetric tetradentate diimines H₂L¹, H₂L² and H₂L³ and the stability constants of their ML type binuclear Ni(II) and Fe(III) complexes have been determined potentiometrically. The asymmetric diimines are (2OH) RCHNC₆H₄CHNR′ (2OH) type compounds [where R = R′ = phenyl for H₂L¹; R = naphthyl, R′ = phenyl for H₂L² and R = R′ = naphthyl for H₂L³]. The effect of tautomeric forms on the acid-base properties of the diimines has been investigated and discussed. In addition, dimeric and binuclear Ni(II) and Fe(III) complexes of the diimines have been synthesized and characterized by physical and spectroscopic techniques. Also, in vitro antimicrobial activities of the diimines and the complexes have been evaluated against three bacteria: Micrococcus luteus (NRLL B-4375), Bacillus cereus (RSKK 863), Escherichia coli (ATCC 11230) and the fungus: Candida albicans (ATCC 10239).     

COPPER(II) PROPIONATES Crystal and Molecular Structure of Bis(propionato)copper(II) Di(methyl-3-pyridylcarbamate)

Abstract

New copper(II) propionate compounds of composition Cu(prop)₂L (L =methyl-3-pyridylcarbamate or N, N-diethylnikotinamide) andau(prop)₂L₂ (L = methyl-3-pyr-idylcarbamate or2, 6-pyridinemethanole) have been prepared. The crystal and molecular structure of thetetrakis(μ-propionato)di(methyl-3-pyridinecarbamate) dicopper(II), Cu-₂(prop)₄(mpc)₂, was determined by direct method and Fouriertechniques. The compound crystallizes in the orthorhombic space group Pcab with four dimeric units in a cell withdimensions a = 19.350(4), b = 15.390(3), c = 10.725(2)Å. The structure was refined byfull-matrix least-squares methods to a R factor of 0.031, based on 3666 independent reflections. Thecompound is dimeric, with square-pyramidal geometry at each copper centre. The two copper atoms are bridgedby four carboxylate groups, while the apical ligands are methyl-3-pyridylcarbamate. The structural dataare compared with those found in similar copper(II) propionates. Spectral data of Cu(prop)₂L aretypical for dimeric copper(II) compounds. Both Cu(prop)₂L₂ compounds seem to possessoctahedral cop-per(II) stereochemistry with differing tetragonal distortion.     

Enantioselective Hydrogenation over Chiral Cobalt Complexes with (+)-(1S,2S,5R)-Neomenthyldiphenylphosphine and (-)-(R,R)-2,2-Dimethyl-4,5-bis(diphenylphosphinomethyl)-1,3-dioxolane

The optical yield in enantioselective hydrogenation of methyl -acetamidocinnamate over mono- and diphosphine cobalt(II) complexes CoX₂L₂ [where X = Cl or CF₃SO₃, L = (+)-(1S,2S,5R)-neomenthyl-diphenylphosphine or L2' = (-)-(R,R)-2,2-dimethyl-4,5-bis(diphenylphosphinomethyl)-1,3-dioxolane], which are generated in situ, in the presence of sodium tetrahydridoborate increases with rise in the phosphine-to-metal ratio and hydrogen pressure. The maximal optical yields of (+)-(S)-N-acetylphenylalanine methyl ester attain 40% (CoX₂L₂) and 42% (CoX₂L₂').     

Direktsynthese von orthometallierten Ketonen des Typs RCO (o-C6H4)Mn(CO)4−nLn (R = Alkyl- und Arylrest,n = 0, 1, 2, L = Ligand)

Direct Synthesis of Orthometallated Ketones of the Type RCO(o-C₆H₄)Mn(CO)_4?nL_n (R = Alkyl and Aryl Groups, n = 0, 1, 2, L = Ligand) The starting materials of the type RMn(CO)_5?nL_n und (C₆H₅)₂ Hg react to the products of the type RCO(o-C₆H₄)Mn(CO)_4?nL_n[n = 0, R = Ch₃, C₂H₅, C₃H₇, C₆H₅,CH₂; R = C₆H₅, n = 1, L = E(C₆H₅)₃, E = P, As, Sb; R = C₆H₅, n = 2, L = P(OR′)₃, R′ = C₆H₅, CH₃, C₂H₅, C₃H₇]. Steps of their complex reaction pathway are proposed. These orthometallated substances have been characterized by means of ¹H-n.m.r., i.r. and u.v. spectroscopic measurements. The determination of the molecular structure of the two compounds RCO(o-C₆H₄)Mn(CO)₃L [R = C₂H₅, L = CO; R = C₆H₅, L = As(C₆H₅)₃] show that both contain a planar heterocyclic five-membered ring of the type .     

The coordination chemistry of simple phospholes: Complexes of nickel(II), palladium(II) and platinum(II)

The reactions between four very simply substituted phospholes and the chlorides of Ni(II), Pd(II) and Pt(II) are described. The phospholes 1-phenylphosphole, 3-methyl-1-phenyl-phosphole and 3,4dimethyl-1-phenylphosphole all readily form bis-complexes of formula L₂MCl₂ [L = phosphole ligand and M = Ni(II), Pd(II) or Pt(II)] or tris-complexes of formula L₃MCI₂. 1-n-Butyl-3,4-dimethylphosphole appears to form stable complexes only with Ni(II). Evidence is put forward which indicates that the L₂MCl₂ complexes exist in a four-coordinate, square-planar monomeric/five coordinate equilibrium while the L₃MCl₂ complexes are primarily the ionic species [L₃MCl]⁺ Cl^? in solution. Comparisons are made with the behaviour of other simple phospholes which do not form Ni(II) complexes and the results are discussed briefly in terms of both aromatic and non-aromatic phosphole models.     

Synthese und Struktur der Cobalt(III)-Komplexe 14gliedriger cis- und trans-N2S2-Dibenzomakrocyclen mit zwei koordinierenden Acetatogruppen

Synthesis and Structure of Cobalt(III) Complexes of 14-Membered cis- and trans-N₂S₂ Dibenzo Macrocycles with two Pendant Acetato Groups The isomeric fourteen membered macrocyclic ligands 6,7,9,15,16,18-hexahydrodibenzo[f,m][1,8]dithia[4,11]diazacyclotetradecine-8,17-diacetic acid-0.5-hydrate (H₂L³), C₂₂H₂₆N₂O₄S₂ · 0.5 H₂O and 6,7,13,15,16,18-hexahydrodibenzo-[e,m][1,4]dithia[8,11]diazacyclotetradecine-14,17-diacetic acid-1.5-hydrate (H₂L⁶), C₂₂H₂₆N₂O₄S₂ · 1.5 H₂O with cis- and trans-N₂S₂ donorsets and two pendant acetato groups form the stable complexes [Co(L³)]ClO₄ · 2 H₂O ( 1 ) and [Co(L⁶)]ClO₄ · H₂O ( 2 ). Co(III) is octahedrally coordinated herein to all six donor centers of the respective ligand. The macrocyclic rings are folded. The metal ions are located outside the macrocyclic cavity. The mean Co? N, Co? O and Co? S distances are 196, 190 and 224 pm, respectively. Crystal data: 1 , monoclinic, space group C2/c, a = 3 797.7(9), b = 763.8(3), c = 2 207.0(7) pm, β = 123.17(2), Z = 8, 3 445 reflections, R(R_w) = 0.072(0.070); 2 , monoclinic, space group C2/c, a = 3 197.1(6), b = 880.4(2), c = 1 890.6(4) pm, β = 112,19(3)°, Z = 8, 4 415 reflections, R(R_w) = 0.062(0.064).     

Synthesis and Structural Characterization of Some Potassium Complexes of Some Bis(phenolate) Ligands and Some Novel Heterobimetallic Binuclear Arrays Formed with Trivalent Lanthanoid Ions

The structural characterizations of the potassium complexes of a pair of dianionic bis(phenolate) ligands, {L^R = [^?OC₆H₂(2,4‐Bu^t)(6‐CH₂)]₂NCH₂CH₂R} R = NMe₂, OMe, crystallized from 1,2,‐dimethoxyethane (DME) are recorded, showing them to take the binuclear form [K₂L^R(DME)₃]. A pair of neutral binuclear heterobimetallic isotypic complexes are defined with ytterbium(III), with phenol, as sodium salts, of the form [Yb(L^R)(OPh)₂Na(DME)(HOPh)], and a further array with samarium(III), of the (partially protonated) form [Sm(L^OMe)₂Na(OH₂)]. A further complex, [Na(DME)₃][Yb(*L^py)₂], results from an unusual ligand reduction by an ytterbium(II) species to give a new dianionic Schiff base ligand which is coordinated to ytterbium(III) {*L^py = ^?OC₆H₂(2,4‐Bu^t)(6‐CH=N‐CH‐2‐C₆H₄N)}.