Synthesis,structures and magnetic properties of a series of polynuclear copper(II)‐lanthanide( III) complexes assembled with carboxylate and hydroxide ligands

Heterometallic copper(II)‐lanthanide(III) complexes have been made with a variety of exclusively O‐donor ligands including betaines (zwitterionic carboxylates) and chloroacetate, which are dinuclear CuLn, tetranuclear Cu₂Ln₂, pentanuclear C_u3Ln₂, and octadecanuclear C_u12 complexes. The results show that subtle changes in both the carboxylates and acidity of the reaction solution can cause drastic changes in the structures of the products. Magnetic studies exhibit that shielding of the Ln³⁺ 4f electrons by the outer shell electrons is very effective to preclude significant coupling interaction between the Ln³⁺ 4f electrons and Cu²⁺ 3d electrons in either a mono‐atomic hydroxide‐bridged, or a carboxylate‐bridged system.     

Coordination chemistry of organometallic polydentate ligand Reactive chemistry of the tridentate ligand trans‐Fe(Ph2PQu‐P)2‐(CO)3 [PhzPQu=2‐diphenyl‐phosphino‐4‐methylquinoline] and molecular structure of [Fe(CO)3(μ‐Ph2PQu)2HgI]+ [HgI3]

Reaction of a new type of bidentate ligand PhPQu [PhPQu = 2‐diphenylphosphino‐4‐methylquinoline] with Fe(CO)₅ in butanol gave trans‐Fe(FpPQu‐P)(CO)₃ (1). Compound 1, which can act as a neutral tridentate organometallic ligand, was reacted with I B, II B metal compounds and a rhodium complex to give six binuclear complexes with Fe? M bonds, Fe(CO)₃ (μ‐Ph₂PQu)MX_n (2–7) [M= Zn(II), Cd(II), Hg(II), Cu(I), Ag(I), Rh(I)], and an ion‐pair complex [Fe(CO)₃ (μ‐Ph₂PQu)₂HgI][HgI₃]^? (8). The structure of 8 was determined by X‐ray crystallography. Complex 8 crystallizes in the space group P‐1 with a = 1.0758(3), b = 1.6210(4), c=1.7155(4)nm; a=75.60(2), β=71.81(2), γ=81.78(2)° and Z = 2 and its structure was refined to give agreement factors of R=0.050 and R_w = 0.057. The Fe‐Hg bond distance is 0.2536nm.     

Synthesis and Crystal Structure of Copper(II) Trifluoroacetates,Cu2(CF3COO)4 · 2 CH3CN and Cu(CF3COO)2(H2O)4

Cu₂(CF₃COO)₄ · 2 CH₃CN ( I ) and Cu(CF₃COO)₂(H₂O)₄ ( II ) have been prepared by concentrating of acetonitrile and aqueous solutions respectively. According to X-ray data, the complex I consists of binuclear molecules with Cu–O 1.969 Å, Cu–N 2.114 Å. The Cu…Cu distance was found to be 2.766 Å, one of the longest for dimeric structures, apparently, due to the high acidity of trifluoroacetic acid. The coordination environment of Cu atom in II can be described as 4 + 2: 2 Cu–O (H₂O) 1.937 Å, 2 Cu–O (CF₃COO) 1.985 Å, 2 Cu–O (H₂O) 2.447 Å. The mononuclear structure is stabilized by formation of two intra- and six intermolecular hydrogen bonds.     

Über röntgenographische Einkristalluntersuchungen an Na2FeAlF7, Na2MIIGaF7 (MII = Ni,Zn) und Na2ZnFeF7 und die Strukturchemie der Weberite

On X-Ray Single Crystal Studies of Na₂FeAlF₇, Na₂M^IIGaF₇ (M^II = Ni, Zn), and Na₂ZnFeF₇ and the Structural Chemistry of Weberites At single crystals of the orthorhombic weberite Na₂NiGaF₇ (a = 716.1, b = 1021.6, c = 740.9 pm; Imma, Z = 4) and of the monoclinic variants (C2/c, Z = 16) Na₂FeAlF₇ (a = 1242.6, b = 727.8, c = 2420.6 pm, β = 99.99°), Na₂ZnGaF₇ (a = 1251.9, b = 730.3, c = 2435.3 pm, β = 99.74°) and Na₂ZnFeF₇ (a = 1261.0, b = 7.359, c = 2453.8 pm, β = 99.70°) complete X-ray structure determinations were performed. The results and the influence of radii on the bridge angles M^II–F–M^II and M^II–F–M^III are discussed in connection with general features within the structural chemistry of 28 weberites.     

Bismut(II)-chalkogenometallate(III) Bi2M4X8, Verbindungen mit Bi24+-Hanteln (M = Al,Ga; X = S,Se)

Bismuth(II) Chalcogenometallates(III) Bi₂M₄X₈, Compounds with Bi₂⁴⁺ Dumbbells (M = Al, Ga and X = S, Se) The ternary bismuth(II) chalcogenometallates(III) Bi₂M₄X₈ (with M = Al, Ga and X = S, Se) were synthesized from the binary chalcogenides M₂X₃ and Bi₂X₃ and elementary bismuth. All compounds are diamagnetic semiconductors with E_g (opt.) = 1.8–2.7 eV. The phases (except Bi₂Al₄Se₈) are thermodynamically stable and decompose peritectically above 965–1020 K. Bi₂Al₄Se₈ is metastable below 825 K and is obtained only by rapid quenching from T > 825 K. The isotypic compounds crystallize in a new tetragonal tP28 structure type (P4/nnc). The characteristic unit is the hitherto unknown clustercation Bi₂⁴⁺, with the mean bond length d(Bi–Bi) = 314.2 pm, the Raman frequency 102 cm^–1 ≤ ν_s ≤ 108 cm^–1, and the mean force constant of f = 0.68 N · cm^–1. The Electron Localization Function, ELF, shows the covalent Bi–Bi bond, the lone electron pairs of the ψ-octahedrally coordinated Bi(II) cations, and the polar character of the Bi–X bonds.     

Synthese und Kristallstrukturen von Quecksilber(II)-iodid-Komplexen mit 3- und 4-pyridylmethylamino- sowie 4-pyridylmethoxy-substituierten Cyclophosphazen-Liganden

Synthesis and Crystal Structures of Mercury(II) Iodide Complexes with 3- and 4-Pyridylmethylamino- and 4-Pyridylmethoxy Substituted Cyclophosphazene Ligands Multifunctional cyclophosphazene ligands with 2-, 3-, and 4-pyridylalkylamino- or 4-pyridylmethoxy groups, N₃P₃(OC₆H₅)₅(NHCH₂(C₅H₄N-2)) ( 1 ), N₃P₃(OC₆H₅)₅ · (NHCH₂(C₅H₄N-3)) ( 2 ), N₃P₃(OC₆H₅)₅(NHCH₂(C₅H₄N-4)) ( 3 ) and N₃P₃(OC₆H₅)₅(OCH₂(C₅H₄N-4)) ( 4 ) are accessible through reactions of monochlorpentaphenoxycyclotriphosphaza-1,3,5-trien with aminomethylpyridine or pyridyl methanolate. 1 does not react with mercury(II) iodide whereas 2–4 yield the metal complexes 2 a , 3 a , and 4 a by interactions of the pyridyl nitrogen atoms. The X-ray single crystal structure analyses of these compounds shows that 2 a and 4 a are dimers, whereas 3 a is a HgI₂ polymer with syndiotacticaly arranged ligands.     

Evidence of a Photo‐Radical Pathway Responsible of the Rearrangement of a Manganese(III)‐Schiff Base Complex in Solution

A new Mn^III‐Schiff base complex, [MnL(OH₂)](ClO₄) ( 1 ) (H₂L = N, N′‐bis‐(3‐Br‐5‐Cl‐salicylidene)‐1, 2‐diimino‐2‐methylethane), an inorganic model of the catalytic center (OEC, Oxygen Evolving Complex) in photosystem II (PSII), has been synthesized and characterized by elemental analysis, IR and EPR spectroscopy, mass spectrometry, magnetic susceptibility measurement and the study of its redox properties by cyclic and normal pulse voltammetry. This complex mimics reactivity (showing a relevant photolytic activity), and also some structural characteristics (parallel‐mode Mn^III EPR signal from partially assembled OEC cluster) of the natural OEC. The complex 1 was found to rearrange in solution into a crystallographically solved square‐pyramidal complex, [MnLL′] ( 2 ) (HL′ = 6‐bromo‐4‐chloro‐2‐cyanophenol), through a process, which probably liberates radical species (detected by EPR), and provokes a C—N bond cleavage in the ligand. A photo‐radical mechanism is discussed to explain this rearrangement.     

Synthesis,Structure and Reactivity of [1, 2‐Bis(diphenylphosphinite)ethane]bromotricarbonylmanganese(I) with Reactions of Phosphites,Phosphonites. and Phosphinites

The manganese carbonyl complex [MnBr(CO)₃ L ] ( 1 ), where L = Ph₂POCH₂CH₂OPPh₂, was prepared by reacting [MnBr(CO)₅] with the bidentate ligand 1, 2‐Bis(diphenylphosphinite)ethane. From this compound and the appropriate phosphite, phosphinite or phosphonite ligands were synthesized the complexes [MnBr(CO)₂ LL ′], where L ′ = P(OMe)₃ ( 2 ) or P(OEt)₃ ( 3 ) and [MnBr(CO)₃ L ′₂], where L ′ =PPh(OEt)₂ ( 4 ) or PPh₂(OEt) ( 5 ). The obtained compounds have been characterized by elemental analysis, mass spectrometry, IR and NMR (¹H, ¹³C and ³¹P) spectroscopies and X‐ray diffractometry for the complexes 1 , 4 and 5 .     

A novel thin-layer amperometric detector based on chemically modified ring-disc electrode and its application for simultaneous measurements of nitric oxide and nitrite in rat brain combined with in vivo microdialysis

A novel thin-layer amperometric detector (TLAD) based on chemically modified ring-disc electrode and its application for simultaneous measurements of nitric oxide (NO) and nitrite (NO₂⁻) in rat brain were demonstrated in this work. The ring-disc electrode was simultaneously sensitive to nitric oxide (NO) and nitrite (NO₂⁻) by modifying its inner disc with electropolymerized film of cobalt(II) tetraaminophthalocyanine (polyCoTAPc)/Nafion and its outer ring with poly(vinylpyridine) (PVP), respectively. The ring-disc electrode was used to constitute a novel TLAD in radial flow cell for simultaneous measurements of NO and NO₂⁻ in rat brain combined with techniques of high performance liquid chromatography (HPLC) and in vivo microdialysis. It was found that the basal concentration of NO in the caudate nucleus of rat brain is lower than 1.0×10⁻⁷ mol l⁻¹, NO₂⁻ concentration is 5.0×10⁻⁷ mol l⁻¹ and NO exists in brain maybe mainly in the form of its decomposed product.     

Synthesis and crystallographic characterization of a ‘palladadehydrobenzo[19]annulene’

The trans-palladium bis(σ-acetylide) complex (Et₃P)₂Pd(C₃₀H₁₂) (2) was synthesized from hexane 4 in 77% yield via a simple three-step process. The X-ray crystal structure of 2 shows a strained and warped annulenic core upon insertion of the organometallic fragment. UV-vis data of the molecule suggest limited electronic delocalization throughout the metallacycle.