Synthesis of the tripyridyldiamine Bn-CDPy3, a chiral pentadentate ligand, and characterization of its low-spin Co(III) complex [Co(Bn-CDPy3)Cl]Cl2 by X-ray crystallography, 1H NMR, 13C NMR, IR and UV-vis spectroscopy as well as molar conductivity and mass spectrometry, is described.

A decanuclear Cd complex has been found as a carbonate-containing capsule. The structure strongly resembles a ten-blade waterwheel with a central carbonate ligand surrounded by two superimposed Cd(5)O(5) crowns with a pentagonal antiprism-like disposition. The capsule is doubly capped by two pentadentate perchlorate anions.

The aza-semi-crown pentadentate ligand rigidified by pyridine and piperidine rings was designed and synthesized. It can react with Mn(II) in water to form complex with improved longitudinal relaxivity, leading to efficient signal intensity enhancement of vascular vessels under a clinical magnetic resonance imaging scanner.

This communication describes the superoxide dismutase (SOD)-like activity of mononuclear iron(III) complexes with pentadentate monocarboxylamido ligands. The SOD activity can be controlled by the electronic nature of the substituent group on the ligand. The nitro-substituted complex showed clear cytoprotective activity against menadione-mediated oxidative stress in cultured cells.

The tptz molecule is reduced by potassium into its anion-radical in the compound K(tptz)(2) (), whereas it is reductively coupled by SmI(2) and UI(3)(py)(4) into the bis-triazinide ligand in the dinuclear complexes [Sm(2)(tptz-tptz)(DMF)(8)][I](4).3.5DMF (.3.5DMF) and U(2)I(6)(tptz-tptz)(MeCN)(2).2MeCN (.2MeCN) where each metal ion occupies a pentadentate N(5) cavity of the [tptz-tptz](2-) ligand.

The Ir(III) compound Tp(Ms'')Ir(N2), that contains a pentadentate, doubly metalated 3-mesityl substituted tris(pyrazolyl)borate ligand, induces the cleavage of C-H and C-Cl bonds of CH2Cl2 to yield a highly electrophilic chlorocarbene Ir=C(H)Cl complex.

A new asymmetric pentadentate ligand was designed to impose low symmetry to trivalent ions. Five-coordinate Fe3+ and Ga3+ complexes were investigated by crystallographic, electrochemical, and electron paramagnetic resonance methods showing enhanced redox reversibility. Calculations were performed to account for the observed trends.

A bio-inspired manganese(ii) complex with a linear pentadentate ligand framework containing soft sulfur donors and an alternating NSNSN binding motif displays excellent dual CAT/SOD-like antioxidant activity with high turnover efficiency and good operation stability in an aqueous environment.

A bis-μ-amidoximato-bridged cobalt(III) dimer obtained with a new tetrapodal ligand possesses interesting structural parameters as a consequence of intramolecular hydrogen bonding intentionally built into the complex. Its synthesis and properties are described. The new ligand type combines attributes of two previously described ligand classes: It binds a metal ion in a tetrapodal pentadentate f...

Oxidations of a trigonal-bipyramidal, high-spin Ni(II) dithiolate complex of a pentadentate, N3S2-donor ligand, N1,N9-bis(imino-2-mercaptopropane)-1,5,9-triazanonane) nickel(II), and the structurally analogous Zn(II) complex, lead to oxidations of the ligand. Oxidation of the Ni(II) complex with I2 produces a novel Ni(II) macrocyclic cationic complex containing a monodentate disulfide ligand (2...