Mixed-Ligand Europium Complexes with Toluic Acid

Europium complexes with toluic acid having the composition Eu(Tol)₃· nD · xH₂O, where Tol^–is the meta-toluate anion, D is 1,10-phenanthroline (n= 2, x= 1), 2,2"-dipyridyl, piperidine, diphenylguanidine, triphenylphosphine oxide (n= 1, x= 2), and H₂O (n= 0, x= 2), were synthesized. The spectroscopic and luminescence properties of these complexes were studied. The title compounds are thermally stable up to 270°C. According to IR spectroscopy, two modes of coordination of the toluate anion, i.e., monodentate and bidentate coordination, can be found in europium toluates.     

Synthesis and Characterization of Some Ruthenium Mixed-Ligand Complexes

The complexation reaction of trans-[RuCl₂(Dpte)₂] (Dpte – (diphenylthio)ethane) with mixed diimine ligands 2,2"-bipyridine, pyridylquinoline, 4,6-dichloro-2-(2-pyridyl)pyrimidine, 4,6-dichloro-5-methyl-2-(2-pyridyl)pyrimidine, and 4,6-dichloro-5-phenyl-2-(2-pyridyl)pyrimidine produces new Ru(II) mixed-ligand complexes. These complexes exhibit maximum photo- and chemical stability and high absorptivity. The above complexes have been characterized using IR, ¹H and ¹³C NMR, electronic absorption spectroscopy, and elemental analysis.     

Chromium(III) and Chromium(IV) Tetraphenylporphine Complexes

Stable chromium complex (AcO)CrTPP was synthesized through the reaction of meso-tetraphenylporphine with chromium(III) acetate in boiling phenol. Coordination properties of chromium porphyrin in reaction with imidazole and pyridine in o-xylene were studied by electronic absorption spectroscopy and computer modeling. A single-electron oxidation of chromium(III) complex was found to be affected by peroxide compounds. The stability of an extra complex depends on the basic properties of the extra ligand and oxidation number of the central metal atom. The complex stability correlates with the calculated energy of formation of the metal–extra ligand bond. The geometrical structure and energy parameters of hexacoordinated chromium porphyrins were calculated using the quantum-chemical method. The effect of the cis and trans position of ligands in the composition of a macrocyclic compound was established to be significant only in the extra complexes (AcO)CrTPP.     

Formation of Mixed-Ligand Complexes of Metals(II) with Monoamine Complexones and Amino Acids in Solution

The formation of mixed-ligand complexes in the M(II)–Nta, Ida–L (M = Cu(II), Ni, Zn, Co(II), L = Ser, Thr, Asp, Arg, Asn) systems, where Ida and Nta are the residues of iminodiacetic and nitrilotriacetic acids, respectively, is studied using pH measurements, calorimetry and spectrophotometry. The thermodynamic parameters (logK, Δ_rG⁰, Δ_rH, Δ_rS) of their formation at 298.15 K and ionic strength I = 0.5 (KNO₃) are determined. The most likely scenario of amino acid residue coordination in the composition of mixed complexes is discussed.     

Mixed-Ligand Europium(III) Complexes with 4-Methylbenzoic Acid

Russian Journal of General Chemistry - Europium(III) complexes with p-methylbenzoic acid and nitrogen- or phosphorus-containing neutral ligand with the compositions [Eu(p-MBA)3·D]2·xH2O...     

钯（II）混配物分子内的芳环堆积作用

用Ｈ ＮＭＲ法研究了钯（ＩＩ）混配物子内芳环配体间的堆积作用，结果表明堆积度和参与堆积的芳环大小一致。     

Mixed-Ligand Ruthenium(II) Complexes as Structural Units of Polynuclear Systems

Spectral and kinetic parameters were studied for phosphine-bipyridyl ruthenium(II) complexes, namely, cis-[Ru(Bipy)₂(PPh₃)X](BF₄), cis-[Ru(Bipy)(Dppe)X₂], and cis-[Ru(Bipy)(Dppene)X₂] (where Bipy is 2,2"-bipyridyl, PPh₃is triphenylphosphine, Dppe is 1,2-bis(diphenylphosphino)ethane, and Dppene iscis-1,2-bis(diphenylphosphino)ethylene; X = CN^–, NO₂ ^–), in the frozen (77 K) alcohol glasses (EtOH–MeOH, 4 : 1). The energies of the singlet and triplet metal-to-ligand charge transfer states d(Ru) *(Bipy) were found to increase in the order [Ru(Bipy)₂X₂] < [Ru(Bipy)₂(PPh₃)X]⁺< [Ru(Bipy)(Dppe)X₂] < [Ru(Bipy)(Dppene)X₂]. The luminescence quantum yields and the rate constants of the nonradiative deactivation of the lowest excited state ³MLCT increase in the same order.     

Features of the Formation of Interpolyelectrolyte Complexes Based on Chitosan and Pectin

Theoretical and Experimental Chemistry - Conditions for the preparation of stable to sedimentation aqueous dispersions of interpolyelectrolyte complexes based on chitosan (Chit) and pectin (Pect)...     

Features of Cobalt(II) Complexes Formation with Pharmacophore-Modified Apple Pectin

Russian Journal of General Chemistry - Complexation of cobalt(II) chloride with apple pectin modified with organic pharmacophores (nicotinic, salicylic, 5-aminosalicylic, or anthranilic acid) has...     

Spectroscopical and Electrochemical Behavior of New Mixed-Ligand Cyclometalated Rh(III) Complexes

The absorption spectra, luminescence spectra, excited-state lifetimes, and electrochemical behavior of the cyclometalated [Rh(ppz)₂bpy]+^, [Rh(3-Cl-ppz)₂(bpy)]⁺, [Rh(4-NO2-ppz)₂(bpy)]⁺, [Rh(ppz)₂(biq)]⁺ and [Rh(4-NO2-ppz)₂(biq)]⁺ complexes (ppz^?, 3-Cl-ppz^?, and 4-NO₂-ppz^? are the ortho-C-deprotonated forms of 1-phenylpyrazole, l-(3-chlorophenyl)pyrazole and l-(4-nitrophenyl)pyrazole, respectively) have been investigated. The results obtained have been compared with those concerning the free protonated ligands and some previously studied mixed-ligand cyclometalated Rh(III) complexes. Luminescence originates from the lowest ligand-centered (LC) excited state, which involves the diimine ligands in all cases except for [Rh(4-NO2-ppz)₂(bpy)]⁺, where it involves the ortho-metalating ligand. s. In the absorption spectra, LC and metal-to-ligand charge-transfer (MLCT) bands, involving the diimine and/or the ortho-metalating ligands, have been assigned, and correlations between spectroscopic and electrochemical data are discussed.     

配体结构对三元混配配合物分子内芳环堆积作用的影响

用ｐＨ电位滴定法测定了含１，１０－邻菲咯啉（Ｐｈｅｎ）和羧酸（ＣＡ）配体的三元混配配合物Ｐｄ（Ｐｈｅｎ）（ＣＡ）＋体系的稳定常数，比较和讨论了各种三元混配物之间的稳定性差异。实验结果表明：在三元混配物Ｐｄ（Ｐｈｅｎ）（ＰＣＡ）＋中（ＰＣＡ，苯基羧酸）存在分子内芳环堆积作用，堆积程度依赖于苯基和配位的羧酸根之间的亚甲基数目，最适宜堆积的苯基羧酸是２－苯乙酸和３－苯丙酸。     

Chemistry of Ruthenium Polypyridine Complexes: V. Electronic Structure of Ruthenium(II) Bipyridine-Diphosphine Mixed-Ligand Complexes

Comparative analysis of the donor-acceptor capacities of diphosphine ligands in two series of complexes: cis-[Ru(bpy)2(LL)]^{q +} [LL = 2,2'-bipyridine (bpy), o-benzoquinonediimine (bqdi), cis-1,2-bis(diphenylphosphino)ethane, cis-1,2-bis(diphenylphosphino)ethylene (dppen), (NH3)2, and (CO)2] and [Ru(NH₃)₄. (LL)]^{2 +} (LL = bpy, dppen, and bqdi), was performed. Diphosphines are the strongest donors; they compare in -acceptor capacity which is associated with phosphorus d orbitals with 2,2'-bipyridine and fall far short of o-benzoquinonediimine and carbonyl.     

几个新的席夫碱合铜(Ⅱ)配合物的合成及性质研究

有关席夫碱类配体及配合物的合成研究非常多,Padhye S.等曾概括过变更席夫碱配合物活性方式^[1],β－二酮席夫碱形成的金属配合物具有仿酶催化活性,在仿生研究中有重要意义;此外,氨基酸类席夫碱含有多个强电负性配位原子,具有较强的配位能力和多样的配位模式的优点,因此,我们合成结构较为复杂的氨基酸席夫碱及其与生命金属铜（II）的配合物,并对合成的配合物的抗菌活性进行了初步研究。     

Complexes of Cyclohexadienones with Aluminum Bromide

Saturated and aromatic monofunctional ketones form with AlBr₃ only 1:1 adducts, -diketones bind 2 mol of AlBr₃, and methylated cyclohexadienones form both 1:1 and 1:2 complexes.     

Coordination Properties of Ga, In, and Tl Tetraphenylporphine Complexes in Reactions with Nitrogen-containing Extra Ligands

The formation of Ga^{3 +}, In^{3 +}, and Tl^{3 +} tetraphenylporphine mixed-ligand complexes (X)MTPP + L = (X)M(L)TPP (X = Cl^-, AcO^-, acac^-; L = N-methylimidazole, imidazole, pyridine, 3,5-dimethylpyrazole, dimethylformamide) in chloroform was studied by spectrophotometric titration and quantum-chemical calculations. The stability of the Ga, In, and Tl porphyrin extra complexes was found to depend on the nature of the acido and nitrogen-containing ligands. The geometric and energetic characteristics of the complexes of six-coordinate gallium and indium porphyrins were calculated. Correlations between calculated and experimental energies of formation and Gibbs energies were found. The cis- and trans-effects of ligands in the extra complexes of metal porphyrins were explained.     

On Nonequivalence of Rare-Earth Ion Positions in Mixed-Ligand Complexes with Acetylacetone and Unsaturated Organic Acids

The luminescence spectra of Eu(III) complexes with diketones and acrylic and maleic acids are analyzed. The transitions are significantly broadened (by a factor of two or three) compared to the starting Eu(III) tris-acetylacetonate. This is explained by the presence of a large number of nonequivalent luminescence centers, originating from diverse (more than five types) modes of coordination of the carboxylic group of unsaturated acids to Eu(III) and by intermolecular association, leading to noncrystalline glasslike structures of the mixed complexes.     

[Ni(dmit)(dmise)]n-混合配体配合物的合成与导电性质

合成了[Ni(dmit)(dmise)]     

Ruthenium(IV) and Osmium(II) Tetraphenylporphine Complexes: Synthesis and Oxidation Reactions

The Ru(IV) and Os(II) complexes (PhO)₂RuTPP and OsTPP were synthesized from tetraphenylporphine (H₂TPP) and K₂RuO₄ or K₂OsO₄ (taken in the molar ratio of 1 : 30) in boiling phenol. The kinetics of oxidation reactions of these complexes in solutions of HOAc (acetic), H₂SO₄, and HOAc–H₂SO₄ acids was studied. It was found that in the aerated HOAc–H₂SO₄ mixture heated above 340 K, these complexes are oxidized with participation of different reaction sites: the Ru(IV) complex is oxidized at macrocycle to give the -radical-cation (PhO)₂RuPP⁺, while in the Os(II) complex, the metal atom is oxidized to form the Os(III) complex. In the first case, the reaction follows the activation mechanism, whereas in the second case, the activation energy of the reaction is zero.     

Solid-Phase Transformations in Tetraamine and Hexaamine Mixed-Ligand Complexes of Chromium(III) with Cyclic Tetraamines

We have studied solid-phase transformations in mixed-ligand complexes of chromium(III) with cyclic tetraamines. We have established that tetraamine complexes of chromium(III) with 14-membered tetraaza macrocyclic ligands are relatively thermally stable, and do not undergo isomerization in the solid state. We have observed that solid-phase reactions of ammonia substitution in hexaamine complexes with outer-sphere iodide and boron hydride anions may be accompanied by dehydrogenation processes.