Search results for "Pyridine"

Crystal Structures and Polymorphism of Nickel and Copper Coordination Polymers with Pyridine Ligands

2014

The crystal structures of a series of pyridine coordination polymers [MIICl2(C5H5N)x]n (M = Ni, Cu), prepared via thermal decomposition are reported. [NiCl2(C5H5N)4] (1) decomposes stepwise via [NiCl2(C5H5N)2]n (2), [NiCl2(C5H5N)]n (3), and [NiCl2(C5H5N)2/3]n (4), to NiCl2 with increasing temperature. The thermal decomposition of [CuCl2(C5H5N)2]n (5), progresses via two polymorphs of [CuCl2(C5H5N)]n (6a and 6b), and [CuCl2(C5H5N)2/3]n (7), to CuCl2. The compounds 3, 4, and 7 were prepared as pure phases. All crystal structures were determined by X-ray powder diffraction. Notably, the crystal structures of the polymorphs 6a and 6b were determined from powder diffraction data of a mixture of …

Homo- and heterobinuclear Cu2+ and Zn2+ complexes of abiotic cyclic hexaazapyridinocyclophanes as SOD mimics

2013

The new receptor 3,7,11,15,19,23-hexaaza-1(2,6)-pyridinacyclotetracosaphane (L1) containing a complete sequence of propylenic chains has been synthesised. The acid–base behaviour and Cu2+ and Zn2+ coordination have been analysed by potentiometric measurements in 0.15 M NaClO4 for L1 and for the related compounds 3,7,11,14,18,22-hexaaza-1(2,6)-pyridinacyclotricosaphane (L2), 3,7,10,13,16,20-hexaaza-1(2,6)-pyridinacycloheneicosaphane (L3) and 3,7,10,12,15,19-hexaaza-1(2,6)-pyridinacycloicosaphane (L4). The crystal structure of [(CuH4L2)(H2O)(ClO4)](ClO4)5·3H2O shows an interesting combination of a metal ion coordinated by the pyridine nitrogen atom and the adjacent amine groups of the chain, …

A Combined DPE/Epoxide Termination Strategy for Hydroxyl End-Functional Poly(2-vinylpyridine) and Amphiphilic AB2-Miktoarm Stars

2011

Observation of electroluminescence at room temperature from a ruthenium(II) bis-terpyridine complex and its use for preparing light-emitting electroc…

2005

A terpyridine ruthenium (II) complex containing a substituted and an unsubstituted terpyridine ligand was synthesized, and its luminescence properties were studied in a solid-state single-layer light-emitting electrochemical cell. The obtained devices emitted light of a very deep red color (CIE, x = 0.717 y = 0.282) at low external applied bias. It is the first example of an electroluminescence device based on a bis-chelated ruthenium complex. Its ambient atmosphere decay is remarkably different from analogous devices using tris-chelated ruthenium complexes.

CO 2 Fixation and Activation by Cu II Complexes of 5,5″‐Terpyridinophane Macrocycles

2007

An aza-terpyridinophane receptor containing the polyamine 4,7,10,13-tetraazahexadecane-1,16-diamine linked through methylene groups to the 5,5″ positions of a terpyridine unit has been prepared and characterized (L). The acid-base behaviour, CuII speciation and ability to form ternary complexes (CuII-L-carbonate) have been explored by potentiometric titrations in 0.15 M NaClO4 and by UV/Vis and paramagnetic NMR spectroscopy. Comparisons are made with a previously reported terpyridinophane containing the polyamine 4,7,10-triazatridecane-1,13-diamine (L1). For this latter receptor, reductive coupling between indigo and carbon dioxide at indigo-modified electrodes produces carboxylated derivat…

Insertion of a [Fe II (pyimH) 3 ] 2+ [pyimH = 2‐(1 H ‐Imidazol‐2‐yl)pyridine] Spin‐Crossover Complex Inside a Ferromagnetic Lattice Based on a Chiral…

2015

The insertion of the [FeII(pyimH)3]2+ [pyimH = 2-(1H-imidazol-2-yl)pyridine] spin-crossover complex into a ferromagnetic bimetallic oxalate network affords the hybrid compound [FeII(pyimH)3][MnIICrIII(ox)3]2·X (ox = C2O42–). This spin-crossover complex templates the growth of crystals formed by a chiral 3D oxalate network. The magnetic properties of this hybrid magnet show the coexistence of long-range ferromagnetic ordering at 4.5 K and a spin crossover of the intercalated [FeII(pyimH)3]2+ complex above 250 K. The compound presents a light-induced excited spin-state trapping (LIESST) effect below 60 K although with limited photoconversion (less than 8 %).

Synthesis, Characterization, and X-ray Crystal Structures of Cyclam Derivatives. 5. Copper(II) Binding Studies of a Pyridine-Strapped 5,12-Dioxocycla…

2004

The copper(II) binding properties of the macrobicyclic diamide 1,9,12,18,22-pentaazatricyclo[7.6.6.1(3,7)]docosa-3,5,7(22)-triene-13,19-dione (L1) have been fully investigated by spectroscopic (IR, UV-vis, EPR, MALDI-TOF MS), X-ray diffraction, potentiometric, electrochemical, and spectroelectrochemical methods. This constrained receptor possesses a hemispherical cavity created by cross-bridging the 1 and 8 positions of trans-dioxocyclam (1,4,8,11-tetraazacyclotetradecane-5,12-dione, L2) with a 2,6-pyridyl strap. Treatment of L1 with a copper salt in methanol produces a red complex of [Cu(L1H(-1))]+ formula in which the copper atom is embedded in a 13-membered ring and coordinated by both a…

Oxygen atom transfer reaction involving oxomolybdenum complexes with sterically bulky thiocarboxylate ligands and biochemical interesting substrates …

1999

Abstract Oxidation–reduction reactions of substrates in systems containing the complex [Mo VI O 2 (O 2 CC(S)CH 3 Ph) 2 ] 2− in methanol have been investigated as models of oxo-transfer reactions. At neutral pH, the [Mo VI O 2 (O 2 CC(S)CH 3 Ph) 2 ] 2− reacts with Me 2 PhP or n -butanethiol to yield a [Mo IV O(O 2 CC(S)CH 3 Ph) 2 ] 2− species and Me 2 PhPO or disulfide, respectively. The Mo IV O complex reduces a variety of substrates XO = Me 2 SO and pyridine N-oxide conducing formation of X = Me 2 S and pyridine. The occurrence of these reactions produces a catalytic system Me 2 PhP + XO → Me 2 PhPO + X and 2BuSH + XO → [BuS] 2  + X + H 2 O. In this work we have also included the study of …

A new Co(ii) coordination solid with mixed oxygen, carboxylate, pyridine and thiolate donors exhibiting canted antiferromagnetism with TC≈ 68 K

2006

Reaction of Co(II) chloride with the sodium salt of 2-mercaptonicotinic acid in water at 200 degrees C results in the formation of Co4(2-mna)4(H2O), which orders as a canted antiferromagnet at 68 K.

Coordinating behaviour of a new pyridylhydrazone; tris-complexes of manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) with 2-pyridylcarb…

1991

The preparation and characterization oftris-complexes of MnII, CoII, NiII, CuII and ZnII with a new pyridylhydrazone, 2-pyridylcarbaldehyde-N,N-dimethylhydrazone (pch), are described. In all the complexes pch behaves as a bidentate ligand binding through the pyridine and azomethyne nitrogen atoms. The complexes appear to be monomeric, high spin six-coordinate, and a distorted octahedral stereochemistry around the metal is suggested. The e.p.r. results for both CuII compounds indicate a mainly dx2−y2 ground state with a static Jahn-Teller distortion, whilst for the MnII complex the e.p.r. data indicates a very low symmetry for the MnN6 polyhedron.