Luminescence kinetic and association equilibria of lanthanide ions in aqueous solutions. II. Determination of the formation constant of Tb acetato complex by means of luminescence lifetime measurement

The association constant K of mono-acetato complex of Tb³⁺ has been determined at normal p and T conditions by measurement of its luminescence lifetime in aqueous solution containing increasing concentrations of acetate. Two experimental arrangements used for the measurement are described.     

Synthesis and Structural Characterization of {[Mn(phen)_2(OAc)(H_2O)]ClO_4}_2H_2O

1 INTRODUCTION Chemistry of manganese cluster has become an attractive research field because of the involvement of manganese in several biological redox-active sys- tems[1,2], especially in the oxygen-evolving complex (OEC) of photosystem Ⅱ (PSⅡ) in green plants[3]. It was thought that the coordination environment of Mn in OEC contains O and N donors, and the bind- ing of aqua to the Mn site may be important to the oxidation of aqua for the evolution of dioxygen[4, 5]. In recent …     

Phosphaniminato‐Acetato‐Komplexe von Cobalt und Cadmium mit M4N4‐Heterocuban‐Struktur

Phosphoraneiminato‐Acetato Complexes of Cobalt and Cadmium with M₄N₄ Heterocubane Structure The phosphoraneiminato‐acetato complexes [M(NPEt₃)(O₂C–CH₃)]₄ with M = Co and Cd are formed from the anhydrous metal(II) acetates with excess Me₃SiNPEt₃ at 180 °C. By crystallization from diethyl ether blue, moisture sensitive single crystals of [Co(NPEt₃) · (O₂C–CH₃)]₄ can be obtained, while colourless single crystals of [Cd(NPEt₃)(O₂C–CH₃)]₄ · 2 CH₂Cl₂ originate from dichloromethane solution. In vacuo the intercalary CH₂Cl₂ is released. The complexes are characterized by their IR spectra and by crystal structure analyses. In both complexes the metal atoms are associated via μ₃–N bridges of the (NPEt₃^–) groups to form heterocubanes. In the cobalt complex the acetato ligands are bonded in a semichelate fashion with a short Co–O and a long Co–O bond each (Co–O distances in average 199.5 and 257.4 pm). In the cadmium complex the acetato groups form almost symmetrical chelates (Cd–O distances in average 232.1 and 237.8 pm); this leads to a distorted trigonal‐bipyramidal arrangement at the cadmium atoms. [Co(NPEt₃)(O₂C–CH₃)]₄: Space group P 1, Z = 4, lattice dimensions at –60 °C: a = 1110.1(2), b = 2051.3(5), c = 2169.5(4) pm, α = 100.03(2)°, β = 103.404(15)°, γ = 97.63(2)°, R = 0.0480. [Cd(NPEt₃)(O₂C–CH₃)]₄ · 2 CH₂Cl₂: Space group C2/c, Z = 4, lattice dimensions at –80 °C: a = 1550.2(1), b = 2101.1(1), c = 1706.1(1) pm, β = 91.09(1)°, R = 0.0311.     

Synthesis of Thienyl‐Substituted Dihydrofuran Compounds Promoted by Manganese(III) Acetate

Radical cyclization reactions of both aliphatic 1,3‐diones 1a and 1b and of cyclic 1,3‐diones 1c – 1e with 2‐thienyl‐ and 3‐thienyl‐substituted alkenes 2a – 2d in the presence of manganese(III) acetate were investigated. Thienyl‐substituted dihydrofurans 3 were obtained with moderate to high yields (Table 1–3). Also, the favorable effect of the thienyl substituent on the intermediate carbocation stability was evaluated by comparison with a phenyl substituent.     

三氮唑配合物[Cu2(CH3COO)4(C4H8N4)2]·2CH3CN的合成及晶体结构

Cu(CH₃COO)₂和4-氨基-3,5-二甲基-1,2,4-三氮唑反应制得标题化合物的单晶[Cu₂(CH₃COO)₄(C₄H₈N₄)₂]·2CH₃CN。晶体属三斜晶系,空间群,a=8.266(2),b=8.585(2),c=10.741(2)Å,α=75.58(3),β=88.     

Structural Studies on Dimethyltin(IV) Carboxylates

In order to correlate ¹¹⁹Sn Mössbauer parameters and structural data for dimethyltin(IV) derivatives, the molecular structures of bis(acetato)dimethyltin(IV) and bis(trifluoroacetato)dimethyltin(IV) were determined by single crystal X-ray diffration. Crystals of Me₂Sn(OOCCH₃)₂ are monoclinic, a = 26.282(4), b = 5.282(1), c = 14.434(3) Å, β = 101.17(2)°, Z = 8, space group C2/c, and those of [Me₂Sn(OOCCF₃)₂]_n are monoclinic, a = 8.444(1), b = 17.689(1), c = 15.368(1) Å, β = 93.013(9)°, Z = 8, space group Cc. The structures were solved by the Patterson method and were refined by full-matrix least-squares procedures to R = 0.025 and 0.027 (R_w = 0.023 and 0.030) for 2 298 and 4 182 reflections with I ≥ 3σ(F²), respectively.     

三氮唑配合物[Cu2(CH3COO)4(C4H8N4)2]·2CH3CN的合成及晶体结构

Cu(CH3COO)2 和4 氨基 3,5 二甲基 1,2,4 三氮唑反应制得标题化合物的单晶[Cu2(CH3COO)4(C4H8N4)2]·2CH3CN。晶体属三斜晶系 ,空间群 ,a=8.266(2),b=8.585(2),c=10.741(2) ,α=75.58(3),β=88.46(3),γ=86.35(3)°,V=736.7(3) 3 ,Z=1,Dc=1.509g·cm 3,F(000)=346,μ=1.502mm 1 。X 射线衍射结构分析表明 ,Cu2(CH3COO)4(C4H8N4)2 单元是中心对称的双核配合物 ,两个铜原子间距为2.698 。每个金属原子被围成四方锥的配位结构 ,四个乙酸根配体中最近的四个氧原子处在底面上[Cu O=1.965(3)～1.986(3) ] ,一个4 氨基 3,5 二甲基 1,2,4 三氮唑配体位于顶点位置Cu N=2.172 。     

Structure of Trinuclear Cadmium Complex with Acetato and Pyridine Ligands

1INTRODUCTIONItisnotedthatmetallothionien(MT)canspecificallycollectheavymetalssuchascadmiumandmercury,butthismettaloproteinisonlyacquiredfrominductiveeffect'illAsmodelsofthepeptidechainsofMT,recentlyanumberofdinucle-inorganism.AsmodelsofthepeptidechainsofMT,recentlyanumberofdinucle-atingSchiffbaseligandswithorwithoutsulphurdonorwassuccessfullyusedtopre-paretrinuclearcadmiumcomplex("31.Ontheotherhand,somemononuclearcadmi-umcomplexeswereformedwhensmallorganicfig'andssuchaspyridinemolecu…