Rational approach to endo/exocoordinated heteronuclear macrocyclic network: supramolecular Hg(ll), Cu(ll), and Hg(ll)/Cu(ll) complexes of a NS4 macrocycle

A rationally designed sulfur-rich macrocycle L incorporating one pyridine and one benzo subunit was synthesized and structurally characterized. From the assembly reactions of L with copper(II) nitrate and mercury(II) iodide, an endocyclic monocopper(II) complex and an exocyclic dimercury(II) complex were prepared, respectively. On the basis of these results, the construction of a Hg(II)/Cu(II) heteronuclear 1D network complex with an endo/exocyclic coordination mode was achieved by one-pot assembly reaction of L with mercury(II) iodide in the presence of copper(II) nitrate.     

Grafting Vinyl Monomers onto Cellulose. IX. Graft Copolymerization of Methyl Methacrylate onto Cellulose Using Peroxydiphosphate-Fe(ll) and Mn(ll) Redox Systems

The vacuum or inert-atmosphere condensation of diphenyl isophthalate and 2,2′,3,3′-tetraaminobiphenyl to poly-2,2′-(m-phenylene)-5,5′-bibenzimidazole has been investigated. Evidence from polymer and model compound (diphenylbibenzimidazole) spectral studies, elemental analysis, and analysis of volatile effluent indicates that the prepolymer formed at 260 to 300°C contains both benzimidazole and hydroxybenzimidazoline but is essentially free from phenoxybenzimidazole structures. A mechanism involving loss of phenol initially, followed by evolution of water to give benzimidazole structures, is established from experimental evidence. Polymerization in vacuum to 400°C gives the polybenzimidazole.     

Synthesis, Crystal Structure, Properties and Thermoanalysis of Complexes of Cu（Ⅱ） and Ni（Ⅱ） with Taurine-5-chlorosalicylaldelyde Schiff Base

The reactions of transition metal salts with taurine 5‐chlorosalicylaldelyde Schiff base gave two complexes [Ni(TCSSB)(H₂O)₃].H₂O (1) and [Cu(TCSSB)(H₂O)₂]₂[Cu(TCSSB)₂].6H₂O (2) (TCSSB=taurine‐5‐chlorosalicylaldelyde Schiff base), which were characterized by elemental analysis and X‐ray diffraction analysis. The complex 1 crystallized in monoclinic system with space group P2 ₁/c, and a=1.4816(2) nm, b=1.3953(2) nm, c= 0.7466(1) nm, β= 100.499(3)°, V=1.5176(4) nm³, Z=4, and an infinite 3‐D network structure was formed by hydrogen bonds among sulfo group, crystal water and coordinated water. Complex 2 crystallized in triclinic system with space group P1 , with the cell parameters: a = 0.6413(2) nm, b= 1.4596(3) nm, c= 1.6188(4) nm, a= 102.473(5)°, β= 98.979(4)°, γ=101.739°, V=1.4165(6) nm³, Z=1. The coordination environment between Cu(1) and Cu(2) is different. Cu(1) is slightly distorted square pyramidal while Cu(2) is distorted square‐plane. The complex 1 is mononuclear while the complex 2 is made up of two coordinated subunits, namely [Cu(TCSSB)₂] and [CU(TCSSB)(H₂O)₂]₂. Besides that the TG‐DTG of the complex 1 was analyzed, the thermal decomposition reaction of the complex was studied under a non‐isothermal condition by TG‐DTG. The TG and DTG curves indicate that the complex was decomposed in three stages: .     

Copper(ll) Complexes of Diamino Diamide and Diamino Diamine in Aqueous Solution

In order to study the difference on the equilibrium, spectral properties of copper(II) complexes of diamino diamide and diamino diamine, new tetradentate ligands, 4,7‐dimethyl‐4,7‐diazadecanediamide (4,7‐N,N′‐Me₂‐L‐2,2,2) and 1,10‐diamino‐4,7‐dimethyl‐4,7‐diazadecane (4,7‐N,N′‐Me₂‐3,2,3‐tet), have been synthesized. Synthetic procedures for these new ligands are described. Their protonation constants have been determined potentiometrically in 0.10 MKC1 at 25.0°C. The formation of their copper(II) complexes have been investigated quantitatively by the potentiometric technique and by the measurement of their electronic spectra.     

Two ferromagnetic azido-bridged copper(ll) complexes studied by first-principle electronic-structure calculation

The electronic structures of two ferromagnetic polynuclear copper(II) complexes, derived from end-to-end azido ligand and tridentate (NNN donor) Schiff base ligand, have been studied using the full-potential linearized augmented plane-wave method based on the density-functional theory. They are [Cu(L1)(micro-1,3-N3)]n(ClO4)n (1) and [Cu(L2)(micro-1,3-N3)]n(ClO4)n (2). The result shows that the spin populations in these two complexes are mainly distributed on the equatorial planes of a square pyramidal that surround the copper(II) ions. There are large and positive spin populations on copper(II) ions, small and positive spin populations on the three nitrogen atoms of tridentate Schiff base ligand, and the two terminal nitrogen atoms of asymmetrical end-to-end azido ligand, while weak and negative spin populations on the central nitrogen atoms of asymmetrical end-to-end azido ligand. Ferromagnetic coupling through the asymmetrical azido ligand in these two complexes has been mainly attributed to the spin delocalization, also with weak spin-polarization effect.     

Kinetic Study of the Ru(II) Catalyzed Oxidation of Pentacyanoferrate(ll) Complexes by Peroxydisulfate

The oxidation reactions of Fe(CN)₅L^3? (L = 4-ampy, py, dpa) complexes by S₂O₈^2? were catalyzed upon the addition of a trace amount of Ru(NH₃)₅L′²⁺ (L′ = pz, py or dcb) complex, and the reaction becomes zero-order in Fe(II). The reaction time is ～10² fold faster than the simple Fe(CN)₅L^3?-S₂O₈^2? system. The mechanism of this Ru(II) catalyzed redox reaction is proposed as Ru(NH₃)₅L′²⁺ + 1/2 S₂O₈^2? → Ru(NH₃)₅L′³⁺ + SO₄^2? Ru(NH₃)₅L′³⁺ + Fe(CN)₅L^3? ? Ru(NH₃)₅L′²⁺ + Fe(CN)₅L^2?     

Kinetics and mechanisms of substitution of aqua-ligands in cis-diaqua-bis(bipyridyl)ruthenium(ll) ion by L-cysteine in aqueous medium

Transition Metal Chemistry - The title reaction has been studied spectrophotometrically and a rate-law established within the pH range 5.0 to 6.5, $$ {?...     

Crystal Structures and Characterizations of Bis（1-benzoyl-methyl-benzotriazole-N^3）dichoro Metal（Ⅱ） Complex： [MCl2（C6H4N3CH2COPh）2] [M=Zn（Ⅱ），Co（Ⅱ）]

The structures of [MCl₂(C₆H₄B₃CH₂COPh)₂] [M=Zn(II) (1), Co(II) (2)] have been determined by X‐ray crystallography. They were characterized by elemental analysis, IR spectrum, electronic spectrum and thermogravimetric‐differential thermal analysis. They all crystallize in the triclinic system, space pup Pi, with lattice parameters a=0.9449(2) nm, b=1.1291(2) nm, c=1.3637(3) nm, α=111.70(3)°, β= 94.33(3)°, y=90.97(3), Z=2 for compound 1; a=0.9437(2) nm, b= 1.1277(2) nm, c= 1.3650(3) nm, a=111.76(3)°, β=94.50(3)°, y=90.80(3)°, Z=2 for compound 2. The metal ions are all coordinated by two C1^?‐ anions and two nitrogen atoms of 1‐benzoylmethyl‐bentriazole ligands. forming the distorted tetrahedral geometry. The Zn—Cl and Zn—N bond lengths are 0.2209(2), 0.2210(2) nm and 0.2059(4), 0.2067(4) nm. respectively. The CO‐Cl 3 and Co–N bond lengths are 0.2215(2). 0.2222(2) nm and 0.2028(5), 0.2045(5) nm. respectively. The thermogravimetric (TG) data indicate that they are nearly similar in TG curve, and there are not structural transitions in the two compounds. They all have a high thd stability. But, there is little difference in DTG (differential thermogravimetric) curves of those two compounds. Elemental analysis, electronic and IR spectra are in agreement with the structural data.     

Catalytic Action of Metallic Salts in Autoxidation and Polymerization. VII. Polymerization of Methyl Methacrylate by Cobalt(ll) or (III) Acetylacetonate-Dioxane Hydroperoxide

Abstract

Polymerization of methyl methacrylate by Co(II or III) acetylacetonate-dioxane hydroperoxide [abbreviated as Co(acac)2, Co(acac)₃, and DOX HPO, respectively] was carried out in dioxane solvent, and the differences in polymerization rate and the degree of polymerization between two initiating systems were compared. Co(acac)₂-DOX HPO for the initiation of the polymerization system was more effective than Co(acac)₃-DOX HPO. The polymerization rate equations for both initiating systems obtained from kinetic data were as follows. For Co(acac)₂-DOX HPO initiating system: R_p=k [M]^3/2[Co(acac)₂]^1/7[DOX HPO]^?