Copper(I) bromide and chloride complexes with urotropine and triethylenediamine: synthesis,crystal structure,and Raman characterization*

Abstract

In the present study, the oxidative dissolution of metallic copper has been explored with the intention to prepare some new complexes with urotropine (hmta) and triethylenediamine (dabco) ligands. All the compounds synthesized were characterized by single-crystal X-ray diffraction and Raman spectroscopy. Reactions performed in a DMSO/CuCl₂?2H₂O mixture resulted in [(μ-Cl)₂Cu^I(hdabco⁺)Cu^I(μ-Cl)(κS-DMSO)]_n and [Cu^ICl(hmta)₂] complexes. Their isostructural bromide analogs [(μ-Br)₂Cu^I(hdabco⁺)Cu^I(μ-Br)(κS-DMSO)]_n and [Cu^IBr(hmta)₂] were prepared by the reaction of elemental copper with respective ligands in a DMSO/CBr₄ mixture. Early interrupted reaction of the copper wire with the DMSO/CBr₄/dabco solution resulted in an appearance of crystals of the [Cu^I₂Br₂(CO)₂(dabco)]_n carbonyl complex on the copper surface. It arises with the participation of in situ formed carbon monoxide. Despite the identical stoichiometry, the crystal structure of the [Cu₂Br₂(CO)₂(dabco)]_n complex is markedly different from that of a known [Cu₂Cl₂(CO)₂(dabco)]_n analog.     

Synthesis,characterization, and DNA binding of ruthenium(II) complexes with 2-benzo[b] furan-2-yl-1H-imidazo[4,5f][1,10]phenanthroline as an intercalative ligand

DNA-binding properties of a number of ruthenium complexes with different polypyridine ligands are reported. The new polypyridine ligand BFIP (=2-benzo[b] furan-2-yl-1H-imidazo[4,5-f][1,10]phenanthroline) and its ruthenium complexes [Ru(bpy)₂BFIP]²⁺ (bpy = 2,2′-bipyridine), [Ru(dmb)₂BFIP]²⁺ (dmb = 4,4′-dimethyl-2,2′-bipyridine), and [Ru(phen)₂BFIP]²⁺ (phen = 1,10-phenanthroline) have been synthesized and characterized by elemental analysis, mass spectra, IR, UV-Vis, ¹H- and ¹³C-NMR, and cyclic voltammetry. The DNA binding of these complexes to calf-thymus DNA (CT-DNA) was investigated by spectrophotometric, fluorescence, and viscosity measurements. The results suggest that ruthenium(II) complexes bind to CT-DNA through intercalation. Photocleavage of pBR 322 DNA by these complexes was also studied, and [Ru(phen)₂BFIP]²⁺ was found to be a much better photocleavage agent than the other two complexes.     

Synthesis,crystal structure,and luminescence of a new zinc(II) coordination polymer based on 2-naphthol-5-carboxylate and 4,4′-bipyridine

To further explore the coordination possibilities of naphthalene-based carboxylic acids, a Zn^II coordination polymer, [Zn₃(L)₆(bipy)₂] _n (1), with bulky 2-naphthol-5-carboxylate (L) and bridging 4,4′-bipyridine (bipy), was synthesized and characterized. Structural analysis reveals that 1 is a 1-D polymeric chain with trinuclear units as nodes, which are further extended via interchain secondary interactions, such as O–H ··· O hydrogen-bonding and aromatic π ··· π stacking interactions, to form an overall 3-D framework. Complex 1 exhibits strong solid-state luminescence emission at room temperature, mainly originating from intraligand π→π* transition of L.     

Synthesis and crystal structure of a triple-decker CuII3TlI2 complex: first example of a thallium(I) system in the imino-phenolate Schiff base ligand family

This report deals with the synthesis, characterization, and crystal structure of a heteropentanuclear Cu^II₃Tl^I₂ compound [(Cu^IIL)₃Tl^I₂](NO₃)₂ (1), where H₂L=N,N′-ethylenebis(3-ethoxysalicylaldimine). This compound crystallizes in the monoclinic crystal system within space group C2/c. Each of the two symmetry related thallium(I) centers is located between a terminal and a common, central [Cu^IIL] by forming bonds with four phenoxo and three ethoxy oxygens. The three [Cu^IIL] moieties are parallel and hence 1 is a triple-decker system. Neighboring triple-decker moieties are interlinked by π?π stacking interaction and weak hydrogen bonds to generate 3-D self-assembly in 1. Salient features in the composition and structure of the title compound are discussed; the title compound is the first example of a thallium(I) system in imino-phenolate Schiff base family.     

AN EQUILIBRIUM AND RATE STUDY OF THE INTERACTION OF AQUEOUS CHROMIUM(III) ION WITH ADENINE

Abstract

Potentiometric titration data obtained at 50° for aqueous solutions containing aquochromium(III) ions and adenine were analyzed to yield values for the acid dissociation constants of adenine and the formation constants of 1:1 and 1:2 mononuclear complexes. There is also evidence for a 2:2 dimer for which elemental analysis data suggest a structure of the form (HL=neutral adenine): [(H₂ O)₂ (HL)Cr-μ(OH)₃ -Cr(HL)(H₂ O)₂]³⁺. The kinetic studies indicate that the 1:1 complex is formed in excess adenine with a half-time of about two hours at pH=4.4 and 60°. The proposed mechanism involves an outer-sphere associative intermediate of appreciable stability (K_A ～ 200) followed by rate-determining substitution of adenine for ligand water to produce the 1:1 complex. A much slower subsequent reaction yields the dimer as the final stable product. The formation of the 1:1 complex is an equilibration and both forward and reverse rate constants were determined. The pH dependence data indicate that the reactive species in the system are HL, Cr(H₂ O) ₅OH²⁺, and Cr(H₂ O)₄ (OH)₂ ⁺.     

Syntheses and structures of three new coordination polymers with the flexible 1,2-bis(1,2,4-triazol-1-yl)ethane ligand

Three new coordination polymers {[Ni(bte)₂(NCO)₂](H₂O)} _n (1), {[Ni(bte)₂(N₃)₂](H₂O)} _n (2) and {[Ag(bte)₂](NO₃)} _n (3) (bte?=?1,2-bis(1,2,4-triazol-1-yl)ethane) were synthesized and characterized by X-ray crystallography, IR and thermogravimetric analysis. The coordination geometry of the Ni(II) atom is distorted octahedral, coordinated equatorially by four nitrogen atoms from four triazole rings of four symmetry-related bte ligands, and axially by two nitrogen atoms from two isocyanate anions in 1 and azide anions in 2, respectively. The structures of 1 and 2 are both polymeric, with 18-membered spiro-fused rings and each 18-membered ring involving two inversion-related bte molecules. The coordination geometry of the Ag(I) atom in 3 is distorted tetrahedral, formed by four nitrogen atoms from four triazole rings of four symmetry-related bte ligands. Each bte ligand links two Ag(I) atoms and forms a two-dimensional undulated (4,4) network in 3.     

Microwave assisted synthesis and characterization of N,N′-bis(salicylaldehydo)ethylenediimine complexes of Mn(II), Co(II), Ni(II), and Zn(II)

Microwave chemistry is a green chemical method that improves reaction conditions and product yields while reducing solvent amounts and reaction times. The main aim of this article is to synthesize the tetradentate N₂O₂ ligand [HO(Ar)CH=N–(CH₂)₂–N=CH(Ar)OH] and manganese(II), cobalt(II), nickel(II), and zinc(II) complexes of the type ML by classical and microwave techniques. The resulting Schiff base and its complexes are characterized by ¹H NMR, infrared, elemental analysis, and electronic spectral data. The ligand and its Co(II) and Mn(II) complexes were further identified by X-ray diffraction and mass spectra to confirm the structure. The results suggest that the metal is bonded to the ligand through the phenolic oxygen and the imino nitrogen.     

Synthesis,Characterization and Crystal Structure of an Unsymmetric Samarium(III) Cryptate

Abstract

The complex [Sm(H₃L)(NO₃)(H₂O)](NO₃)₂ · H₂O was synthesized by the (2+3) condensation of tris(2-aminoethyl)amine with 2,6-diformyl-4-chlorophenol in the presence of Sm³⁺. Its crystal structure has been determined. In the complex the coordination number of Sm³⁺ is nine. A water molecule is encapsulated in the cryptate as a guest, confirmed by electrospray mass spectrometry, thermal analysis and the X-ray crystal structure.