Complexes of dicamba with cadmium(II), copper(II), mercury(II), lead(II) and zinc(II)

New solid complexes of a herbicide known as dicamba (3,6-dichloro-2-methoxybenzoic acid) with Pb(II), Cd(II), Cu(II) and Hg(II) of the general formula M(dicamba)₂·xH₂O (M=metal, x=0-2) and Zn₂(OH)(dicamba)₃·2H₂O have been prepared and studied. The complexes have different crystal structures. The carboxylate groups in the lead, cadmium and copper complexes are bidentate, chelating, symmetrical, in Hg(dicamba)₂·2H₂O - unidentate, and in the zinc salt - bidentate, bridging, symmetrical. The anhydrous compounds decompose in three stages, except for the lead salt whose decomposition proceeds in four stages. The main gaseous decomposition products are CO₂, CH₃OH, HCl and H₂O. Trace amounts of compounds containing an aromatic ring were also detected. The final solid decomposition products are oxychlorides of metals and CuO. This revised version was published online in July 2006 with corrections to the Cover Date.     

Complexation of managanese(II), cobalt(II), nickel(II), zink(II), and cadmium(II) cations with amoxicillin

The interaction of amoxicillin anions (Axn^?) with Mn²⁺, Co²⁺, Ni²⁺, Zn²⁺, and Cd²⁺ in aqueous solution at 20°C and an ionic strength of 0.1 (KNO₃) has been studied pH-metrically. In a neutral and weak alkaline solution, MAxn⁺ and M(OH)Axn complexes are formed. The formation constants and the pH ranges of existence of these complexes have been determined.     

Cadmium(II), manganese(II) and zinc(II) compounds

Three new compounds, [Cd(μ ₃ -Hpdh)(μ₂-Cl)] _n (1), Mn(Hpdh)₂(H₂O)₂ (2) and Zn(Hpdh)₂ (H₂O)₂ (3) (H₂pdh =?pyridine-2,3-dicarbo-2,3-hydrazide), have been synthesized and characterized by elemental analysis, IR spectra, TG and single-crystal X-ray diffraction. Under hydrothermal conditions, H₂pdh is generated by an in situ acylation of H₂pda (H₂pda =?pyridine-2,3-dicarboxylic acid) with hydrazine hydrate. Complex 1 features a 2D layer structure constructed by a dinuclear Cd(II) building block. In complexes 2 and 3, hydrogen bonding interactions connect mononuclear structures into 3D supramolecular frameworks.     

New Complexes of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) with 3,3-dimethylglutaric Acid

Conditions for the preparation of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II)3,3-dimethylglutarates were investigated and their quantitative composition, solubility in water at 293 K and magnetic moments were determined. IR spectra and powder diffraction patterns of the complexes prepared with general formula MC₇H₁₀O₄⋅nH₂O (n=0−2) were recorded and their thermal decomposition in air were studied. During heating the hydrated complexes of Mn(II),Co(II), Ni(II) and Cu(II) are dehydrated in one step and next all the anhydrous complexes decompose to oxides directly (Mn, Co, Zn) or with intermediate formation free metal (Ni,Cu) or oxocarbonates (Cd). The carboxylate groups in the complexes studied are bidentate. The magnetic moments for the paramagnetic complexes of Mn(II), Co(II), Ni(II) and Cu(II)attain values 5.62, 5.25, 2.91 and 1.41 M.B., respectively. This revised version was published online in August 2006 with corrections to the Cover Date.     

Tetrathioureamercury(II) tetrathiocyanatomanganate(II)

In the title complex, [Hg(CH₄N₂S)₄][Mn(NCS)₄], the Hg and Mn atoms sit at special positions with symmetry and are tetrahedrally coordinated to four thio­urea (TU) S and four thio­cyanate (SCN) N atoms, respectively. The structure consists of discrete cationic and anionic [Hg(TU)₄]²⁺ and [Mn(SCN)₄]²⁻ complexes, and weak N_TU—H⃛S_SCN hydrogen-bond bridges exist between these complexes.     

Chelated complexes of cadmium(II), cobalt(II), copper(II), mercury(II), nickel(II), uranyl(II) and zinc(II) with benzil bis(4-phenylthiosemicarbazone)

Summary Complexes of Co^II, Ni^II, Cu^II, Zn^II, Cd^II, Hg^II and UO ₂ ^II with benzil bis(4-phenylthiosemicarbazone), H₂BPT, have been synthesized and their structures assigned based on elemental analysis, molar conductivity, magnetic susceptibility and spectroscopic measurements. The i.r. spectra suggest that the ligand behaves as a binegative quadridentate (NSSN) (Co^II, Cu^II, Hg^II and UO ₂ ^II complexes) or as a binegative quadridentate-neutral bidentate chelating agent (Ni^II, Zn^II and Cd^II complexes). Octahedral structures for the Co^II and Ni^II complexes and square-planar structure for the Cu^II complex are suggested on the basis of magnetic and spectral evidence. The crystal field parameters (Dq, B and _B) for the Co^II complex are calculated and agree fairly well with the values reported for known octahedral complexes. The ligand can be used for the microdetermination of Ni^II ions of concentration in the 0.4–6×10^–4 mol l^–1 range and the apparent formation constant for the species generated in solution has also been calculated.     

Synthesis and chemical characterization of biologically important complexes of vanillin thiosemicarbazone with manganese(II), iron(II), cobalt(II), nickel(II), copper(II), zinc(II), cadmium(II), and mercury(II)

Summary Vanillin thiosemicarbazone (VTSC) has been used to isolate the complexes of the types [M(VTSC)₂(H₂O)₂]X₂ (M=Mn^II, Fe^II, Co^II, or Ni^II and X=Cl) and [M(VTSC)X₂]H₂O (M=Cu^II, Zn^II, Cd^II or Hg^II and X=Cl). Probable structures of these complexes are suggested on the basis of elemental analysis, molar conductance, magnetic moment and electronic and i.r. spectral data. The fungicidal activity of VTSC and the isolated complexes has been evaluated on pathogenic fungi,Alternaria (Sp.),Paecilomyces (Sp.) andPestalotia (Sp.).On leave from the University of Myosore.     

Reaction of cefalexine with manganese(II), cobalt(II), nickel(II), zinc(II), and cadmium(II) ions

The reaction of cefalexine anions (Cpx^?) with Mn²⁺, Co²⁺, Ni²⁺, Zn²⁺, and Cd²⁺ ions in aqueous solution at 20°C and ionic strength 0.1 was studied by pH-metry. In weakly alkaline medium, unstable complexes MCpx⁺ and M(OH)Cpx are formed, in which Cpx^? behaves as a monodentate lidand coordinated through the amino group.     

Thiamorphinane II

The present paper is dealing with two isomeric series of 5,5a,6,7,8,9-hexahydro-5,9a-iminoethano-4H-naphthothiophenes (thiamorphinans) which were synthesized as a new type of potential narcotic analgesics.

Herrn Prof. Dr.K. Schlögl mit besten Wünschen zum 60. Geburtstag gewidmet.     

Preparation and characterization of vanillin thiosemicarbazone complexes with Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II)

Complexes of vanillin thiosemicarbazone (3-methoxy-4-hydroxybenzaldehyde thiosemicarbazone), (vtsch) with several divalent metal ions have been isolated. Structures have been assigned to these complexes based on electrical conductivity, magnetic susceptibility and spectroscopic measurements     

Formation of Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Ag(I) and Cd(II) hexacyanocobaltates

A study is reported of the formation of Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Ag(I) and Cd(II) hexacyanocobaltates. The results show that the precipitates form by reaction of the metal ions with KCo(CN)(6)(2-) ion-pairs in 1:1 ratio, followed by solid phase transformations.     

Zinc(II), cadmium(II), mercury(II), and ethylmercury(II) complexes of phosphinothiol ligands

Neutral zinc, cadmium, mercury(II), and ethylmercury(II) complexes of a series of phosphinothiol ligands, PhnP(C6H3(SH-2)(R-3))3-n (n = 1, 2; R = H, SiMe3) have been synthesized and characterized by IR and NMR ((1)H, (13)C, and (31)P) spectroscopy, FAB mass spectrometry, and X-ray structural analysis. The compounds [Zn{PhP(C6H4S-2)2}] (1) and [Cd{Ph2PC6H4S-2}2] (2) have been synthesized by electrochemical oxidation of anodic metal (zinc or cadmium) in an acetonitrile solution of the appropriate ligand. The presence of pyridine in the electrolytic cell affords the mixed complexes [Zn{PhP(C6H4S-2)2}(py)] (3) and [Cd{PhP(C6H4S-2)2}(py)] (4). [Hg{Ph2PC6H4S-2}2] (5) and [Hg{Ph2PC6H3(S-2)(SiMe3-3)}2] (6) were obtained by the addition of the appropriate ligand to a solution of mercury(II) acetate in methanol in the presence of triethylamine. [EtHg{Ph2PC6H4S-2}] (7), [EtHg{Ph2P(O)C6H3(S-2)(SiMe3-3)}] (8), [{EtHg}2{PhP(C6H4S-2)2}] (9), and [{EtHg}2{PhP(C6H3(S-2)(SiMe3-3))2}] (10) were obtained by reaction of ethylmercury(II) chloride with the corresponding ligand in methanol. In addition, in the reactions of EtHgCl with Ph2PC6H4SH-2 and with the potentially tridentate ligand PhP(C6H3(SH-2)(SiMe3-3)) 2, cleavage of the Hg-C bond was observed with the formation of [Hg{Ph2PC6H4S-2}2] (5) and [Hg(EtHg) 2{PhP(O)(C6H3(S-2)(SiMe3-3))2}2] (11), respectively, and the corresponding hydrocarbon. The crystal structures of [Zn3{PhP(C6H4S-2)2}2{PhP(O)(C6H4S-2)2}] (1*), [Cd2{Ph2PC6H4S-2}3{Ph2P(O)C6H4S-2}] (2*), 3, 5, 6, [EtHg{Ph2P(O)C6H4S-2}] (7*), 8, 9, [{EtHg}2{PhP(O)(C6H3(S-2)(SiMe3-3))2}] (10*), and 11 are discussed. The molecular structures of 1, 2, 4, 7, and 10 have also been studied by means of density functional theory (DFT) calculations.     

Copper(II), cobalt(II), nickel(II) and mercury(II) complexes of 1,4-diphenylthiosemicarbazide

Summary The preparation and characterization of Cu^II, Co^II, Ni^II and Hg^II complexes containing 1,4-diphenylthiosemicarbazide (DPhTSC) of the type [Cu(DPhTSC-H)X.H₂O]nH₂O (X= Cl, Br or Ac; n=0 or 1) · [M(DPhTSC-H)₂yH₂O] (M=Co^II or Ni^II; y=0 or 1) and [Hg(DPhTSC)Cl₂]2 H₂O and [Cu(D-PhTSC)₂SO₄]H₂O are reported. The stereochemistry of the complexes have been studied with the help of magnetic and electronic measurements. The anomalous magnetic moments observed in all cases have been explained. The i.r. spectral studies have been used to determine the bonding sites in the complexes.     

Thermal decompositions of formates. Part IV. Thermal dehydrations of Mg(II), Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) formate dihydrates

The thermal dehydrations of formate dihydrates of Mg(II), Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) were studied by means of thermogravimetry, differential thermal analysis and differential scanning calorimetry in air.The reaction orders of dehydration obtained by the dynamic and the static methods were found to be 2/3 for all the salts examined, which indicated that the rate of dehydration was controlled by a chemical process at a phase boundary. This was confirmed by microscopic observation.The values of activation energy, frequency factor and the enthalpy change of dehydration for all salts examined, were 21–30 kcal mole^?1, 10¹⁰-10¹² sec^?1 and 28–31 kcal mole^?1, respectively.The temperature at which the dehydration occurred was regarded as a measure of the strength of the metalOH₂ bond, and this temperature increased with increasing the reciprocal of the radius of the metallic ion.     

Trifluoromethylfurans II

Ethyl acetoacetate reacted with 3-bromo-1,1,1-trifluoro-2-propanone in the presence of base to give 3-carbethoxy-4,5-dihydro-4-hydroxy-2-methyl-4-trifluoromethylfuran (I). Acid catalyzed dehydration of I gave the corresponding furan (III). Saponification of III gave 2-methyl-4-trifluoromethyl-3-furoic acid which was decarboxylated to yield 2-methyl-4-trifluoromethylfuran (V) for which a structure proof is presented. Conversion of the methyl groups of III and V to formyl groups is described.     

Mesophases II

In the continuation of a review of the classification, properties and applications of mesophases, the general features of thermodynamic data of thermotropic liquid–crystalline phase transitions are surveyed. The orientation of molecules in liquid–crystalline mesophases is discussed in relation to the electrical properties. Some applications of mesophases are outlined. After surveys of both the structural classes of lyotropic mesophases and the properties of plastic crystals in cubic phases, the thermodynamic, structural and other properties of all mesophases-are summarily considered in relation to the present state of the knowledge in this field.