Crystal structure of ammonium bis-[(pyridin-2-yl)meth-yl]ammonium dichloride.

In the title molecular salt, C12H14N3 (+)·NH4 (+)·2Cl(-), the central, secondary-amine, N atom is protonated. The bis-[(pyridin-2-yl)meth-yl]ammonium and ammonium cations both lie across a twofold rotation axis. The dihedral angles between the planes of the pyridine rings is 68.

Crystal structure of ortho-rhom-bic {bis-[(pyridin-2-yl)meth-yl](3,5,5,5-tetra-chloro-pent-yl)amine-κ(3) N,N',N''}chlorido-copper(II) perchlorate.

In the title compound, [CuCl(C17H19Cl4N3)]ClO4, the Cu(II) ion adopts a distorted square-planar geometry defined by one chloride ligand and the three nitro-gen atoms from the bis-[(pyridin-2-yl)meth-yl](3,5,5,5-tetra-chloro-pent-yl)amine ligand. The perchlorate counter-ion is disordered over three sets of sites with refined occupancies 0.0634 (17), 0.

Structural studies of (prop-2-en-1-yl)bis[(pyridin-2-yl)methylidene]amine hetero-scorpionate copper complexes.

The structures of five compounds consisting of (prop-2-en-1-yl)bis[(pyridin-2-yl)methylidene]amine complexed with copper in both the Cu(I) and Cu(II) oxidation states are presented, namely chlorido{(prop-2-en-1-yl)bis[(pyridin-2-yl)methylidene]amine-κ(3)N,N',N''}copper(I) 0.18-hydrate, [CuCl(C15H17N3)]·0.18H2O, (1), catena-poly[[copper(I)-μ2-(prop-2-en-1-yl)bis[(pyridin-2-yl)methylidene]amine-κ(5)N,N',N'':C(2),C(3)] perchlorate acetonitrile monosolvate], {[Cu(C15H17N3)]ClO4·CH3CN}n, (2), dichlorido{(prop-2-en-1-yl)bis[(pyridin-2-yl)methylidene]amine-κ(3)N,N',N''}copper(II) dichloromethane monosolvate, [CuCl2(C15H17N3)]·CH2Cl2, (3), chlorido{(prop-2-en-1-yl)bis[(pyridin-2-yl)methylidene]amine-κ(3)N,N',N''}copper(II) perchlorate, [CuCl(C15H17N3)]ClO4, (4), and di-μ-chlorido-bis({(prop-2-en-1-yl)bis[(pyridin-2-yl)methylidene]amine-κ(3)N,N',N''}copper(II)) bis(tetraphenylborate), [Cu2Cl2(C15H17N3)2][(C6H5)4B]2, (5).

Electron-Poor Thiophene 1,1-Dioxides: Synthesis, Characterization, and Application as Electron Relays in Photocatalytic Hydrogen Generation.

The synthesis and characterization of electron-poor thiophene 1,1-dioxides bearing cyanated phenyl groups are reported. The electron-accepting nature of these compounds was evaluated by cyclic voltammetry, and highly reversible and facile reductions were observed for several derivatives. Moreover, some of the reduced thiophene dioxides form colorful anions, which were investigated spectroelectrochemically.

Crystal structure of {(but-3-en-1-yl)bis-[(pyridin-2-yl)meth-yl]amine-κ(3) N,N',N''}di-chlorido-copper(II) diethyl ether hemisolvate.

The five-coordinate Cu(II) atom in the title complex [CuCl2(C16H19N3)]·0.5C4H10O, adopts a near-ideal square-pyramidal geometry (τ-5 = 0.01).

Properties and ATRP activity of copper complexes with substituted tris(2-pyridylmethyl)amine-based ligands.

Synthesis, characterization, electrochemical studies, and ATRP activity of a series of novel copper(I and II) complexes with TPMA-based ligands containing 4-methoxy-3,5-dimethyl-substituted pyridine arms were reported. In the solid state, Cu(I)(TPMA*(1))Br, Cu(I)(TPMA*(2))Br, and Cu(I)(TPMA*(3))Br complexes were found to be distorted tetrahedral in geometry and contained coordinated bromide anions. Pseudo-coordination of the aliphatic nitrogen atom to the copper(I) center was observed in Cu(I)(TPMA*(2))Br and Cu(I)(TPMA*(3))Br complexes, whereas pyridine arm dissociation occurred in Cu(I)(TPMA*(1))Br.

Tuning thiophene with phosphorus: synthesis and electronic properties of benzobisthiaphospholes.

1,4-Dimercapto-2,5-diphosphinobenzene and 3,6-bis(hexyloxy)-1,4-dimercapto-2,5-diphosphinobenzene were synthesized and combined with various acid chlorides to obtain a series of benzobisthiaphospholes. Electrochemical and photophysical properties of the substituted benzobisthiaphospholes have been evaluated, and the observed reductions are more facile than the related benzothiaphospholes and 2,6-diphenylbenzobisthiazole. A benzobisthiaphosphole with C6H4-p-CN substituents was reduced at E(1/2)=-1.

[Ir(N^N^N)(C^N)L]+: a new family of luminophores combining tunability and enhanced photostability.

The relatively unexplored luminophore architecture [Ir(N^N^N)(C^N)L](+) (N^N^N = tridentate polypyridyl ligand, C^N = 2-phenylpyridine derivative, and L = monodentate anionic ligand) offers the stability of tridentate polypyridyl coordination along with the tunability of three independently variable ligands. Here, a new family of these luminophores has been prepared based on the previously reported compound [Ir(tpy)(ppy)Cl](+) (tpy = 2,2':6',2″-terpyridine and ppy = 2-phenylpyridine). Complexes are obtained as single stereoisomers, and ligand geometry is unambiguously assigned via X-ray crystallography.

Kinetic and mechanistic aspects of atom transfer radical addition (ATRA) catalyzed by copper complexes with tris(2-pyridylmethyl)amine.

Kinetic and mechanistic studies of atom transfer radical addition (ATRA) catalyzed by copper complexes with tris(2-pyridylmethyl)amine (TPMA) ligand were reported. In solution, the halide anions were found to strongly coordinate to [Cu(I)(TPMA)](+) cations, as confirmed by kinetic, cyclic voltammetry, and conductivity measurements. The equilibrium constant for atom transfer (K(ATRA) = k(a)/k(d)) utilizing benzyl thiocyanate was determined to be approximately 6 times larger for Cu(I)(TPMA)BPh(4) ((1.

Crystal structures of Au2 complex and Au25 nanocluster and mechanistic insight into the conversion of polydisperse nanoparticles into monodisperse Au25 nanoclusters.

We previously reported a size-focusing conversion of polydisperse gold nanoparticles capped by phosphine into monodisperse [Au(25)(PPh(3))(10)(SC(2)H(4)Ph)(5)Cl(2)](2+) nanoclusters in the presence of phenylethylthiol. Herein, we have determined the crystal structure of [Au(25)(PPh(3))(10)(SC(2)H(4)Ph)(5)Cl(2)](2+) nanoclusters and also identified an important side-product-a Au(I) complex formed in the size focusing process. The [Au(25)(PPh(3))(10)(SC(2)H(4)Ph)(5)Cl(2)](2+) cluster features a vertex-sharing bi-icosahedral core, resembling a rod.

Atom transfer radical addition (ATRA) catalyzed by copper complexes with tris[2-(dimethylamino)ethyl]amine (Me6TREN) ligand in the presence of free-radical diazo initiator AIBN.

In this article, we focus on the evaluation of tris[2-(dimethylamino)ethyl]amine (Me(6)TREN) ligand in copper catalyzed ATRA in the presence of free-radical diazo initiator AIBN (2,2'-azobis(2-methylpropionitrile)). The addition of carbon tetrachloride to 1-hexene, 1-octene and cis-cyclooctene proceeded efficiently to yield 89, 85 and 85% of monoadduct, respectively, using the catalyst to alkene ratio of 1 : 2500. For alkenes that readily undergo free radical polymerization, such as methyl acrylate, catalyst loadings as high as 0.

Photoinitiated ambient temperature copper-catalyzed atom transfer radical addition (ATRA) and cyclization (ATRC) reactions in the presence of free-radical diazo initiator (AIBN).

The use of UV light in copper-catalyzed atom transfer radical addition (ATRA) and cyclization (ATRC) reactions of various (poly)halogenated compounds to highly active alkenes in the presence of AIBN is reported. Radicals generated from photodecomposition of AIBN efficiently regenerated the copper(I) complex at ambient temperature enabling ATRA of CCl(4) and CBr(4) with catalyst loadings as low as 0.05 mol-%.

Copper-catalyzed atom transfer radical addition (ATRA) and cyclization (ATRC) reactions in the presence of environmentally benign ascorbic acid as a reducing agent.

In recent years, copper-catalyzed atom transfer radical addition (ATRA) has emerged as a viable organic procedure for the formation of carbon-carbon bonds starting from alkyl halides and alkenes. Studies have primarily focused on the use of free-radical initiators to regenerate the copper(I) complex or activator in situ. Although these initiators led to a significant decrease in the amount of metal catalyst, they were much less effective for highly active alkenes that readily undergo free-radical polymerization.

Structural comparison of copper(I) and copper(II) complexes with tris(2-pyridylmethyl)amine ligand.

Copper(I) complexes with the tris(2-pyridylmethyl)amine (TPMA) ligand were synthesized and characterized to examine the effect of counteranions (Br(-), ClO(4)(-), and BPh(4)(-)), as well as auxiliary ligands (CH(3)CN, 4,4'-dipyridyl, and PPh(3)) on the molecular structures in both solid state and solution. Partial dissociation of one of the pyridyl arms in TPMA was not observed when small auxiliary ligands such as CH(3)CN or Br(-) were coordinated to copper(I), but was found to occur with larger ones such as PPh(3) or 4,4'-dipyridyl. All complexes were found to adopt a distorted tetrahedral geometry, with the exception of [Cu(I)(TPMA)][BPh(4)], which was found to be trigonal pyramidal because of stabilization via a long cuprophilic interaction with a bond length of 2.

Total structure determination of thiolate-protected Au38 nanoparticles.

We report the total structure of Au(38)(SC(2)H(4)Ph)(24) nanoparticles determined by single crystal X-ray crystallography. This nanoparticle is based upon a face-fused Au(23) biicosahedral core, which is further capped by three monomeric Au(SR)(2) staples at the waist of the Au(23) rod and six dimeric staples with three on the top icosahedron and other three on the bottom icosahedron. The six Au(2)(SR)(3) staples are arranged in a staggered configuration, and the Au(38)S(24) framework has a C(3) rotation axis.

Kinetic studies of the initiation step in copper catalyzed atom transfer radical addition (ATRA) in the presence of free radical diazo initiators as reducing agents.

Kinetic parameters for the reduction of copper(II) complexes in atom transfer radical addition (ATRA) in the presence of free-radical diazo initiator (AIBN) were determined using both experimental and kinetic modeling techniques. The rate constant of decomposition of AIBN (k(dc)) in various solvents was determined at 60 degrees C using UV-vis spectroscopy. Rate constants of deactivation (k(d,AIBN)) of [Cu(II)(TPMA)Cl][Cl] (TPMA = tris(2-pyridylmethyl)amine), [Cu(II)(Me(6)TREN)Cl][Cl] (Me(6)TREN = tris[2-(N,N-dimethylamino)ethyl]amine), [Cu(II)(PMDETA)Cl(2)] (PMDETA = N,N,N',N'',N''-pentamethyldiethylenetriamine), and [Cu(II)(bpy)(2)Cl][Cl] (bpy = 2,2'-bipyridine) complexes by radicals generated from the decomposition of AIBN were measured using the TEMPO-trapping method in a competitive clock reaction.

Persistent radical effect in action: kinetic studies of copper-catalyzed atom transfer radical addition in the presence of free-radical diazo initiators as reducing agents.

Kinetic features of the atom transfer radical addition (ATRA) of CCl(4) to 1-octene, styrene, and methyl acrylate catalyzed by [Cu(II)(TPMA)Cl][Cl] (TPMA = tris(2-pyridylmethyl)amine) in the presence of free-radical diazo initiator (AIBN) as a reducing agent were investigated. For 1-octene, the catalyst concentration was found to affect the alkene conversion and the yield of monoadduct for [1-octene](0)/[Cu(II)](0) ratios above 10,000:1. A more pronounced effect of the catalyst loading was observed in the case of methyl acrylate and styrene, due to the formation of AIBN-initiated oligomeric/polymeric side products.

Copper catalyzed atom transfer radical cascade reactions in the presence of free-radical diazo initiators as reducing agents.

Exceptional activity of [Cu(II)(TPMA)Cl][Cl] (TPMA = tris(2-pyridylmethyl)amine) complex in atom transfer radical addition (ATRA) of CCl(4) to 1,6-dienes followed by sequential atom transfer radical cyclization (ATRC) in the presence of free-radical diazo initiators as reducing agents is reported.

Strong coordination of tetraphenylborate anion to copper(I) bipyridine and phenanthroline-based complexes and its effect on catalytic activity in the cyclopropanation of styrene.

The synthesis, characterization, and cyclopropanation activity of tetrahedral copper(I) complexes with bipyridine- and phenanthroline-based ligands containing strongly coordinated tetraphenylborate anions are reported. Cu(I)(bpy)(BPh(4)), Cu(I)(phen)(BPh(4)), and Cu(I)(3,4,7,8-Me(4)phen)(BPh(4)) complexes are the first examples in which the BPh(4)(-) counterion chelates a transition metal center in bidentate fashion through eta(2) pi interactions with two of its phenyl rings.

Atom transfer radical addition and polymerization reactions catalyzed by ppm amounts of copper complexes.

Over the past decade, copper-catalyzed atom transfer radical polymerization (ATRP) has had a tremendous impact on the synthesis of polymeric materials with well defined compositions, architectures and functionalities. Apart from synthetic aspects of ATRP, considerable effort has also been devoted to structural and mechanistic understanding of copper complexes involved in ATRP, as well as development of methodologies to decrease the amount of catalyst needed in these systems. This tutorial review reports on recent advances in the area of catalyst regeneration in ATRP and mechanistically similar atom transfer radical addition (ATRA) using environmentally benign reducing agents.

Atom transfer radical addition in the presence of catalytic amounts of copper(I/II) complexes with tris(2-pyridylmethyl)amine.

Highly efficient atom transfer radical addition of polyhalogenated compounds to alkenes catalyzed by copper(I/II) complexes with tris(2-pyridylmethyl)amine in the presence of a radical initiator [2,2'-azobis(2-methylpropionitrile)] was reported.

General method for determination of the activation, deactivation, and initiation rate constants in transition metal-catalyzed atom transfer radical processes.

A general method for the determination of the activation (ka), deactivation (kd), and initiation (ki) rate constants in atom transfer radical processes is reported. The method involves the monomer trapping techniques and the analytical solution of the persistent radical effect. For tert-butyl 2-bromopropionate, using ATRP catalyst [CuI(dNbpy)2][Br] and methyl methacrylate in CH3CN at 22 degrees C, the values of ka, kd, and ki were determined to be (9.