2-[2-(2-Pyrid-yl)eth-yl]isoindolinium perchlorate.

In the title salt, C(15)H(17)N(2) (+)·ClO(4) (-), the isoindoline N atom is protonated and an intra-molecular N-H⋯N hydrogen bond occurs. In the crystal, N-H⋯O and numerous weak C-H⋯O inter-actions occur between the cation and anion. The O atoms of the perchlorate anion are disordered over four sets of sites with occupancies of 0.

A photolabile ligand for light-activated release of caged copper.

A photosensitive caged copper complex has been prepared from a tetradentate ligand (H2cage) composed of two pyridyl-amide arms connected by a photoreactive nitrophenyl group. H2cage binds Cu2+ in aqueous solution with a stability constant (log beta) of 10.8, which corresponds to a KD of 16 pM at pH 7.

(m-Phenyl-enedimethyl-ene)diammonium p-nitro-phenyl-phosphate perchlorate.

The title compound, C(8)H(14)N(2) (2+)·C(12)H(8)N(2)O(8)P(-)·ClO(4) (-), was formed by the reaction of α,α-bis-m-xylenediamine and sodium bis-p-nitro-phenyl-phosphate in the presence of Zn(ClO(4))·6H(2)O in methanol solution. The two amine groups of the m-xylenediammonium ion are each protonated and each hydrogen-bonded to two O atoms of the phosphate anion, which acts as a 1,3-bridge. The ammonium groups are arranged matched face to face and each pair is doubly bridged by two perchlorate ions through hydrogen bonding.

Di-μ-bromido-bis-({bis-[2-(2-pyrid-yl)eth-yl]amine}copper(II)) bis-(perchlorate).

Each Cu atom in the dinuclear centrosymmetric title complex, [Cu(2)Br(2)(C(14)H(17)N(3))(2)](ClO(4))(2), is ligated in a distorted square-pyramidal geometry (τ = 0.31) by a tridentate bis-[2-(2-pyrid-yl)eth-yl]amine ligand, and by two bridging Br atoms. In addition, the dinuclear species is stabilized by two hydrogen-bonded perchlorate anions.

Counterions influence reactivity of metal ions with cysteinyldopa model compounds.

Cysteinyldopas are naturally occurring conjugates of cysteine and dopa (3,4-dihydroxy-l-phenylalanine) that are precursors to red pheomelanin pigments. Metal ions are known to influence pheomelanogenesis in vitro and may be regulatory factors in vivo. Cydo (3-[(2-amino-ethyl)sulfanyl]-4,6-di-tert-butylbenzene-1,2-diol) and CarboxyCydo (2-amino-3-(4,6-di-tert-butyl-2,3-dihydroxyphenylsulfanyl)-propionic acid) are model compounds of cysteinyldopa that retain its metal-binding functionalities but cannot polymerize due to the presence of blocking tert-butyl groups.

[(6-Methyl-2-pyridylmeth-yl)(2-pyridylmeth-yl)amine][(2-pyridylmeth-yl)amine]copper(II) bis-(perchlorate).

The title compound, [Cu(C(6)H(8)N(2))(C(13)H(15)N(3))](ClO(4))(2), is a mixed ligand complex with the Cu(II) atom coordinated by (6-methyl-2-pyridylmeth-yl)(2-pyridylmeth-yl)amine, acting as a tridentate ligand, and 2-(2-amino-meth-yl)pyridine, as a bidentate ligand, leading to an N(5) square-pyramidal geometry. The amine H atoms are involved in hydrogen bonding to the perchlorate O atoms and there are extensive but weak inter-molecular C-H⋯O inter-actions in the crystal structure. The perchlorate ions are each disordered over two positions, with site occupancies of 0.

(Acetonitrile)[bis-(2-pyridylmeth-yl)amine]bis-(perchlorato)copper(II).

In the title compound, [Cu(ClO(4))(2)(C(12)H(13)N(3))(C(2)H(3)N)], the Cu(II) atom is six-coordinate in a Jahn-Teller distorted octahedral geometry, with coordination by the tridentate chelating ligand, an acetonitrile mol-ecule, and two axial perchlorate anions. The tridentate ligand bis-(2-pyridylmeth-yl)amine chelates meridionally and equatorially while an acetonitrile mol-ecule is coordinated at the fourth equatorial site. The two perchlorate anions are disordered with site occupancy factors of 0.

Synthesis and characterization of copper(II) complexes of cysteinyldopa and benzothiazine model ligands related to pheomelanin.

A new cysteinyldopa model ligand Cydo {3-[(2-aminoethyl)sulfanyl]-4,6-di-tert-butylbenzene-1,2-diol} was prepared and its reactivity with Cu(II) explored. Under anaerobic conditions, tetranuclear [Cu4(Cydo)4] is isolated, but in the presence of O2, a benzothiazine intermediate accumulates that is trapped as the Cu(II) complex [Cu(zine)2]. Under slightly different reaction conditions, the benzothiazine further oxidizes to benzothiazole (zole).

Studies of a dinuclear manganese complex with phenoxo and bis-acetato bridging in the Mn2(II,II) and Mn2(II,III) states: Coordination structural shifts and oxidation state control in bridged dinuclear complexes.

The dinucleating ligand, 2,6-bis{[(2-(2-pyridyl)ethyl)(2-pyridylmethyl)-amino]-methyl}-4-methylphenol) (L1OH) reacts with Mn(ClO4)2.6H2O to form the dinuclear complex [Mn2(II,II)(L1O)(mu-OOCCH3)2]ClO4 (1). The electrolytic oxidation of 1 at 0.

Dioxo-bridged dinuclear manganese(III) and -(IV) complexes of pyridyl donor tripod ligands: combined effects of steric substitution and chelate ring size variations on structural, spectroscopic, and electrochemical properties.

The syntheses and structural, spectral, and electrochemical characterization of the dioxo-bridged dinuclear Mn(III) complexes [LMn(mo-O)(2)MnL](ClO(4))(2), of the tripodal ligands tris(6-methyl-2-pyridylmethyl)amine (L(1)) and bis(6-methyl-2-pyridylmethyl)(2-(2-pyridyl)ethyl)amine (L(2)), and the Mn(II) complex of bis(2-(2-pyridyl)ethyl)(6-methyl-2-pyridylmethyl)amine (L(3)) are described. Addition of aqueous H(2)O(2) to methanol solutions of the Mn(II) complexes of L(1) and L(2) produced green solutions in a fast reaction from which subsequently precipitated brown solids of the dioxo-bridged dinuclear complexes 1 and 2, respectively, which have the general formula [LMn(III)(mu-O)(2)Mn(III)L](ClO(4))(2). Addition of 30% aqueous H(2)O(2) to the methanol solution of the Mn(II) complex of L(3) ([Mn(II)L(3)(CH(3)CN)(H(2)O)](ClO(4))(2) (3)) showed a very sluggish change gradually precipitating an insoluble black gummy solid, but no dioxo-bridged manganese complex is produced.