Synthesis of N-tetrasubstituted cyclam derivatives appended with sulfonyl or sulfinyl groups via aza-Michael addition

Azamacrocycles bearing four arylsulfonyl or arylsulfinyl pendant arms have been synthesised with good yields through nucleophilic addition of 1,4,8,11-tetraazacyclotetradecane (cyclam) to phenylvinylsulfone, phenylvinylsulfoxide or (R)-tolylvinylsulfoxide in isopropanol/water media. The crystal structure of the tetraethylsulfonylphenyl substituted macrocycle has been determined by X-ray crystallography. Preliminary studies of the coordination properties of these functionalised macrocyles towards Cu(II) and Eu(III) indicate that pendant sulfoxide groups act as oxygen donor coordinating groups.     

Preparation and characterization of Mg(II)-, Ca(II) and Cd(II) complexes of 1,2-ethanediol and water

Mixed ligand complexes of different compositions were prepared with water, sulfate ion and 1,2-ethanediol as ligand. IR spectra and the thermoanalytical curves of the complexes were recorded. Oxygen atoms bound by one or two coordinate bonds to the metal ion, or by hydrogen-bonds in the crystal, were observed. As for the water molecule, 1,2-ethanediol molecules of crystal and monohydrate type were found, depending on the type of binding of the oxygen atoms.This revised version was published online in November 2005 with corrections to the Cover Date.     

19-Electron arenecyclopentadienyl complexes of ruthenium

A series of are necyc lope ntadienyl complexes,i. e., [Ru(⁵-c₅R₅)(⁶- are ne)]⁺ (1, R= H, arene = C₆H₆; 2, R = Me, arme = C₆H₆; 3, R = H, arctic = C₆H₃Me₃; 4, R = Me, arene = C₆H₃Me₃; 5, R = H, arene = C₆Me₆; 6, R = Me, arene = C₆Me₆) was studied by cyclic voltammetry. These compounds are capable of both oxidation and reduction. The reduction potential values depend on the number of methyl groups in the complex. Reduction of benzene complexes I and 2 by sodium amalgam in THF leads to the formation of decomplexation products, the addition of hydrogen to benzene, and dimerization of the benzene ligands. Both chemical and electrochemical reductions of mesitylene complexes3 and4 result in dimeric products [(⁵-C₅R₅)Ru(-⁵;⁵-Me₃H₃C₆H₃Me₃)Ru(⁵-C₅R₅)] (14, R = H; 15, R = Me). The action of sodium amalgam on compound5 gives products of hydrogen addition to both hexamethylbenzene (17) and cyclopentadienyl (18) ligands along with the major product, the dimer [⁵-C₅H₅)Ru(-⁵; ⁵-Me₆C₆C₆Me₆)Ru(⁵-C₅H₅)] (16). In contrast to5, its permcthylated analog 6 is only capable of adding hydrogen to the hexamethylbenzene ligand.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1691–1697, July, 1996.     

Modular design of icosahedral metal clusters

The concept of crystalline module, that is, an unambiguously isolated, repeated quasi-molecular element, is introduced. This concept is more general than the concept of crystal lattice. The generalized modular approach allows extension of the methods and principles of crystallography to quasi-crystals, clusters, amorphous solids, and periodic biological structures. Principles of construction of aperiodic, nonequilibrium regular modular structures are formulated. Limitations on the size of icosahedral clusters are due to the presence of spherical shells with non-Euclidean tetrahedral tiling in their structure. A parametric relationship between the structures of icosahedral fullerenes and metal clusters of the Chini series was found.     

Synthesis of cationic complexes [(C<Subscript>4</Subscript>Me<Subscript>4</Subscript>)CoL]<Superscript>+</Superscript> (L is naphthalene,phenanthrene, and anthracene)

Cationic arene complexes [Cb*Co(naphthalene)]⁺ (2, Cb* = C₄Me₄) and [Cb*Co(phenanthrene)]⁺ were synthesized by the reactions of [Cb*Co(MeCN)₃]⁺ with arenes. The [Cb*Co(anthracene)]⁺ complex was synthesized by the abstraction of the iodide ion from [Cb*CoI]₂ by TIBF₄ in the presence of anthracene. Complex 2 exchanges the naphthalene ligand for other arenes at room temperature. Dedicated to Academician G. A. Abakumov on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1861–1863, September, 2007.     

Use of Ag(II) as a removable template in porphyrin chemistry: diol cleavage products of [meso-tetraphenyl-2,3-cis-diolchlorinato]silver(II)

The use of Ag^II as a removable template in synthetic porphyrin chemistry is described. Mild procedures for the insertion of Ag^II into chlorins and the demetallation of the [chlorinato]Ag^II complexes are delineated. The UV-vis spectra of the novel [chlorinato]Ag^II complexes are discussed. The diol cleavage products of [meso-tetraphenyl-2,3-diolchlorinato]silver(II) under a number of conditions are characterized and compared to those resulting from the cleavage of the corresponding free base diol chlorin or its Ni^II complex, highlighting the unique templating effect of Ag^II. The scopes and limits of electrospray ionization mass spectrometry (ESI-MS) for the analysis of Ag^II chlorins is described. The use of Ag^II as a templating metal is superior over Ni^II or Zn^II for the preparation of free base pyrrole-modified porphyrins along metal templated pathways.     

Synthesis, X-ray structure and properties of a new nitrite-bound copper(II) complex with 2-(3,5- dimethylpyrazol-1-ylmethyl)pyridine in a CuN4(O) coordination

Synthesis and characterization of a nitrite-bound copper(II) compound [CuL⁴)₂(ONO)]ClO₄ have been achieved (L⁴ = 2-(3,5-dimethylpyrazol-1-ylmethyl)pyridine]. The bidentate ligand L⁴ provides a pyridine and a pyrazole donor site; however, they are separated by a methylene spacer. The complex has been structurally characterized and it belongs to only a handful of complexes having nitrito-bound mononuclear copper(II) centre. The metal atom has a distorted square pyramidal geometry with the copper atom displaced from the equatorial plane by 0.25 Å. In MeCN solution the green complex exhibits a broad ligand-field transition at 655 nm with a shoulder at 675 nm and in dichloromethane-toluene glass (80 K) it exhibits an EPR spectral feature characteristic of the unpaired electron in the d_x²−y² orbital. Variable-temperature (80–300 K) magnetic susceptibility measurements in the solid state as well as room temperature measurement in MeCN solution reveal mononuclear magnetically dilute copper(II) centre. When examined by cyclic voltammetry (MeCN solution) it displays electrochemically irreversible Cu^II---Cu^I response [cathodic peak potential, E_pc (V vs saturated calomel electrode (SCE)): −0.32]. An oxidative response is observed at 1.14 V, probably due to bound-nitrite oxidation and is partially removed to generate a solvated complex at the electrode surface. The latter species gives rise to reversible Cu^II---Cu^I redox response [ ].     

Charge transfer complexes and salts of ionenes

A review of the synthesis and properties of ionenes is presented. Particular attention is paid to the electrical and related properties of conductive teteracyano-p-quinodimethane (TCNQ) complex salts of ionenes containing ammonium or sulfonium groups in the main chain and to their chemical stability. The recent work on preparation of such ionenes with inorganic and organic counterions which show interesting linear and nonlinear optical properties is also discussed. It is shown that in the solid state ionenes act as a kind of a matrix fixing, in a chemically controlled way, positions and distribution of different kinds of counterions. Because the reaction of counterion exchange is easy in the case of ionenes it provides a convenient way to prepare a broad class of polyelectrolytes with many different properties.     

Emission,Emissionslebensdauer und Absorption von [Cr urea6]X3-Einkristallen

Emission and absorption polarization spectra as well as emission lifetimes between room temperature and 5 °K have been measured of [Cr urea₆]X₃ single crystals, where X stands for ClO ₄ ^– , J^–, NO ₃ ^– , Br^–, Cl^–, F^–, and X₃ for JSO ₄ ^3– . The strong temperature dependence of the fluorescence/phosphorescence-ratios, and of the emission lifetimes is discussed. The differences between the spectra as well as the emission lifetimes of the various salts can be attributed to an anion dependent trigonal perturbation.

Die Autoren danken dem Verband der Chemischen Industrie für finanzielle Unterstützung dieser Arbeit.