Synthesis and characterization of carbon-bridged bis(phenolate) lanthanum alkoxides and their catalytic behavior for the polymerization of L-lactide

Four lanthanum alkoxides stabilized by a carbon-bridged bis(phenolate) ligand were synthesized and their catalytic behavior for the ring-opening polymerization of L-lactide was explored. Reactions of [(MBMP)LaCp(THF) 2 ] (MBMP 2 = 2,2′-methylene-bis(6-tert-butyl-4-methyl phenoxo)) with HOCH 2 Ph, HOCH 2 CF 3 , HOCH(CH 3 ) 2 , and HOCH 2 CH 2 N(CH 3 ) 2 , respectively, in a 1:1 molar ratio in THF gave the dimeric lanthanum alkoxo complexes [(MBMP)Ln(μ-OR)(THF) 2 ] 2 (OR = OCH 2 Ph(1), OCH 2 CF 3 (2), OCH(CH 3 ) 2 (3), OCH 2 CH 2 N(CH 3 ) 2 (4)]. These complexes were well characterized, and the definitive molecular structure of complex 1 was determined. It was found that complexes 1 to 4 are efficient initiators for the ring-opening polymerization of L-lactide. The structure of the alkoxo groups has a significant effect on the catalytic behavior, and complex 2 can initiate L-lactide polymerization in a controlled manner.     

Well-defined bis（phenolate） lanthanide methoxides as efficient initiators for the polymerization of cyclic carbonate and lactide

Lanthanide methoxides supported by carbon-bridged bis(phenolate) ligands 2,2′-methylene-bis(6-tert- butyl-4-methylphenoxo) (MBMP2-) [(MBMP)Ln( μ-OMe)(THF)2]2 (Ln = Nd (1), Yb (2)) were synthesized in high yields by the protolysis reaction using (C5H5)3Ln(THF) as starting materials, and complex 1 was structurally characterized. The coordination geometry around the center metal can be best described as a distorted octahedron. Complexes 1 and 2 were shown to be efficient initiators for the ring-opening polymerization of 2,2-dimethyltrimethylene carbonate (DTC) and L-lactide. The mechanism of DTC polymerization was explored by the end group analysis of the oligomer.     

Enolate chelating N-heterocyclic carbene complexes of Fe(II): Synthesis, structure and their catalytic activity for ring-opening polymerization of ε-caprolactone

The reaction of anhydrous FeBr2 with two equivalents of anionic N-heterocyclic carbene (NaL1 and NaL2), which are generated in situ by the reaction of the corresponding salt [4-R-C6H4COCH2{CH- (NCHCHNiPr)}Br] (R = OCH3, H2L1Br, 1; R = F, H2L2Br, 2) with two equivalents of NaN(SiMe3)2, affords bis-ligand Fe(II) complexes of L12Fe (3) and L22Fe (4) in high yield, respectively. Attempt to synthesize mono-ligand Fe(II) bromide by the 1:1 molar ratio of NaL to FeBr2 is unsuccessful, and the same com- plexes of 3 and 4 were obtained. Both 3 and 4 have been depicted by elemental analysis and X-ray structure determination. Preliminary studies show that both 3 and 4 can be used as single-component catalyst for the ring-opening polymerization of ε-caprolactone, and the catalytic activity of 3 is higher than that of 4.     

Synthesis,characterization and photoluminescence of aluminum <Emphasis Type="Italic">N</Emphasis>-aryloxo functionalized <Emphasis Type="Italic">β</Emphasis>-ketoiminate complexes

The synthesis, characterization and luminescent properties of aluminum complexes containing a dianionic N-aryloxo functionalized β-ketoiminate ligand are presented. 4-(2-Hydroxy-5-R-phenyl)imino-2-pentanone (R = Me, L¹H₂; R = tert-butyl, L²H₂) ligands reacted with AlEt₃ in tetrahydrofuran to give the aluminum complexes (L¹AlEt)₂ (1) and (L²AlEt)₂ (2) in reasonable isolated yields. X-ray diffraction revealed that complexes 1 and 2 have solvent-free centrosymmetric dimeric structures, and each aluminum center has distorted trigonal bipyramidal geometry. At room temperature, complexes 1 and 2 exhibit blue photoluminescence in acetonitrile with maximum emission wavelengths of 419 and 413 nm, respectively.     

Preparation of (R)- and (S)-2-Allyl-1, 3, 2-dinaphtho (α, β) [d.f] dioxaborepin and their reactions with aldehydes

(R)- and(S)-2-Allyl-1,3,2-dinaphtho (α,β) [d.f] dioxaborepin ((R)-2 and(S)-2) have been first prepared by the reaction of(R)-(+)- or(S)-(−)-1, 1′-bi-2-naphthol and triallylborane in THF at room temperature, respectively.(S)-2 and(R)-2 are sensitive to moisture and oxygen in air and disproportionate easily to triallylborane and 1,1′-bi-2 naphthyl bis (1,1′-bi-2-naphtholborate) at ambient temperature. However, THF is a stabilizer for them. The reactions of(R)-2 or(S)-2 and some aliphetic or aromatic aldehydes in CH₂Cl₂ at −78°C for several hours afforded β-alkylenyl alcohols in up to 84.8%ee. Among them, optically active 1-(3, 5-dichlorophenyl)-3-butenol and 1-(2-methoxyphenyl)-3-butenol were first prepared Foundation item: Supported by the National Natural Science Foundation of China (29972033) Biography: Liu Dejun (1973), male, Ph. D, research direction: asymmetric synthesis     

Structural diversity and reactivity of d^10 metal- （4-pyridylthio）acetate system

The hydrothermal synthesis and crystal structures of four coordination polymers, namely, 2D [Zn（μ3-ta）（pytaH）]n （1）, 2D [Zn（μ3-pyta）Cl]n （2）, 1D [Cd（μ-pyta）2（H2O）]n （3）, and 3D [Cd（μ3-pyta）（μ-Cl）]n （4） （pyta = （4-pyridylthio）acetate, ta = thioglycolate）, are reported. They are based on （4-pyridylthio）acetate and its derived ligand. The ta^2- ligand present in 1 was generated from an in situ C（sp^2）-S bond cleavage of the pyta ligand. In these compounds, versatile intermolecular interactions, such as close S…S interactions and strong （O-H…O/N/S） or weak （C-H…O/S, C-H…Cl） hydrogen bonding interactions, play an important role in the formation of three-dimensional supramolecular networks in the solid state.     

Inorganic-organic hybrids constructed of bis（undecatungstogerma- nate）lanthanates polyoxoanions and oxalate-bridged dinuclear copper complexes and their magnetic properties

A series of inorganic-organic hybrids K₂Na _m H_9−m [{Ln(GeW₁₁O₃₉)₂}{Cu₂(bpy)₂(μ-ox)}]·nH₂O (bpy = 2,2-bipyridine and ox = oxalate; Ln = La, Nd, Sm, Eu, Gd; n = 19, 17, 22, 20, 19; m = 4, 4, 4, 9, 2) were isolated after reacting in a potassium acetate buffer. X-ray structural analyses show that compounds 1–5 are isomorphic and consist of [Ln(GeW₁₁O₃₉)₂]¹³⁻ polyoxoanion building blocks and oxalate-bridged dinuclear copper metalorganic complex with a 1D chain structure. The 1D chain further connects into the 3D framework by π-π interactions with neighboring bpy groups. The magnetic susceptibility data indicate that antiferromagnetic coupling between the neighboring Cu²⁺ ions in the structure and the rare earth ions affects magnetic property of the structure.     

稀土烯丙基化合物的研究(XV)——含环戊二烯基或吡咯基的异核混配型稀土烯丙基配合物的合成

以２－甲基烯丙基氯化镁与无水稀土氯化物低温下反应,得到含镁２－甲基烯丙基稀土配合物（Ｌｎ（Ｃ４Ｈ７）２（Ｍｇ２Ｃｌ５（ＴＨＦ）４）．该配合物与环戊二烯或吡咯进行配体取代反应,分别得到两个系列的含环戊二烯基（Ｃ５Ｈ５）或吡咯基（Ｃ４Ｈ４Ｎ）的异核混配型稀土烯丙基配合物（Ｌｎ２（Ｃ５Ｈ５）３（Ｃ４Ｈ７）Ｍｇ３Ｃｌ８（ＴＨＦ）６,Ｌｎ２（Ｃ４Ｈ４Ｎ）３（Ｃ４Ｈ７）Ｍｇ３Ｃｌ８（ＴＨＦ）６（Ｌｎ＝Ｃｅ,Ｐｒ,Ｎｄ））．这２个配合物均经元素分析、红外光谱、质谱鉴定及摩尔电导的测定     

Synthesis, structure and property of serial p-carboxylphenoxyacetate-lanthanide coordination polymers

Four novel lanthanide-based coordination polymers, [Ln（PBDC）（HPBDC）（H2O）3] （H=PBDC=p-carboxylphenoxyacetate; Ln = La （1）, Pr （2）, Nd （3）） and [La=（PBDC）3（H2O）4] （4）, have been prepared through hydrothermal synthetic methods. Compounds 1-3 are isomorphous and exhibit one-dimensional （1D） chain-like motifs, while compound 4 features a complicated three-dimensional （3D） architecture, which is designed and synthesized based on the inspiration from the structure characterization of compound 1. Under the similar reaction conditions, the carboxyl in compound 1 may be further deprotonated by adding the organic base of 2,2′-bipyridine. This subtle change caused a significant difference in the structures, from 1D chain of 1 to a 3D structure of 4. In addition, IR, UV-Vis, TGA and magenetic properties are also investigated in this paper.     

Synthesis,structure and catalytic behavior of yttrium complexes bearing a diaminobis（phenolate） ligand

Yttrium complexes stabilized by a diaminobis（phenolate） ligand were synthesized and their catalytic behavior was explored. Reaction of YCI3 with 1 equiv of LNa2 [L= Me2NCH2CH2N{CH2-（2-O-C6H2-^1Bu2-3,5）}2] gave the yttrium chloride LYCI（THF） （1） in 92% yield. Complex I can be used as starting material to prepare the yttrium amido derivative. Complex 1 reacted with 1 equiv of LiNPh2 in THF to afford the expected yttrium amido complex LYNPh2 （2） in high yield. Both of complexes 1 and 2 have been well detected by elemental analysis, NMR spectra and single-crystal X-ray analysis. It was found that complex 2 can efficiently initiate the ring-opening polymerization of L-lactide and ε-caprolactone, and a controlled manner is observed in the former case.     

Raman and infrared spectroscopic investigation of some hydrous LnTPPTS complexes (Ln=La,Sm)

The Raman and IR spectra of LnTPPTS·10H₂O [Ln=La,Sm, TPPTS=P(m-C₆H₄SO₃) ₃ ³⁻ ] complexes are reported. Based on the observed Raman and IR characteristic frequencies, a vibrational assignments has been made for these complexes. Coordination induces a lengthening of the S−O bonds and a shortening of the C−S bond. The C−S stretching frequencies should therefore increase while the position of the should move to a lower wavenumber. Vibrational modes of metal-oxygen polyhedron V _(La-O) at 146, 168,253 cm⁻¹ are the structural charactrization for coordinate bond of LnTPPTS complexes. Chen Zhenhua: Born in 1938, Professor     

Investigation on the coordinate structures of the rare earth metal complexes with edta and cydta ligands

0　IntroductionThegreatattentionhasbeenpaidtorareearthorradioactiverareearthmetalcomplexesfortheirvariousbiologicactivi ties[1 3] .Forexamples,theradioactiverareearthmetal1 53SmⅢ com plexeswerewidelyusedfortumourtherapyofbrain ,liver,lung ,heartandbonetissues[4 5] ;forrareearthmetalEuⅢandTbⅢemitinguniquefluorescence ,theircompoundswereappliedfordiagnosesofvariousdiseases[6 ,7] ;forrareearthmetalGdⅢcontainingthemosthigh spinsingleelectrons,itscomplexeswereusuallyusedforcontrastagentsofmag…     

Polymerization of acrylonitrile catalyzed by lanthanide-sodium alkoxide clusters Lne（OCH2CH2NMe2）12（OH）eNas [Ln=Yb （1）, Nd （2） and Sm （3）]

Polymerization of acrylonitrile was carried out using,for the first time,the lanthanide-sodium alkoxide clusters Ln2(OCH2CH2NMe2)12(OH)2Na8 [Ln=Yb (1),Nd (2) and Sm (3)] as single component catalysts.These heterobimetallic complexes exhibit high activity and give atactic polyacrylonitriles with high molecular weight.The polymerization temperature can be varied over the range ?78 to 50°C.The solvent has a substantial effect on the polymerization activity.The order of activity for solvents is DMF>DME≈toluene≈...     

Synthesis and spectroscopy of nitridoruthenium (VI) and osmium (VI) porphyrins

Reaction of Ru (4-Cl-TPP) (CO) (MeOH) [4-Cl-TPP = meso-kis (4-chlorophenyl) porphyrinato dianion] with 3-chloroperoxybenzoic acid (m-CPBA) followed by treatment of the mixture with an aqueous ammonia solution afforded the first nitrido ruthenium porphyrin Ru(4-Cl-TPP) (N) (OH). Three new nitrido osmium (VI) porphyrins, Os (Por) (N) (OH) (Por=TPP, TTP, and 4-Cl-TPP), were synthesized from oxidation of Os(Por)(NH₃)₂ withm-CPBA. All these new complexes were characterized by¹H NMR, IR, UV/Visible spectra and elemental analyses. Both nitrido ruthenium (VI) and osmium (VI) porphyrins are diamagnetic. Their pyrrole proton resonances appear at slightly lower fields than those of the corresponding dioxo Ru(VI) and Os(VI) porphyrins. The {ie89-1}, or {ie89-2}, region is obscured by the strong “oxidation state marker” band. Li Zaoying: born in July 1949, associate professor. Curent research interest is in the study on synthesis and properties of macrocyclic polyamine and complexes     

Synthesis,Structural Characterization,and Electrochemical Properties of Binuclear Copper(Ⅱ) Complexes Containing Tetradentate Schiff Base Ligand

Two binuclear copper(Ⅱ) complexes, [Cu2(saloph)2 (μ-O)2]-2(DMF)[H2saloph=N,N′-o-phenylenebis(salicylideneaminato)] (a) and [Cu2(salen)2(μ-O)2] [H2salen=N,N′-bis(salicylic-deneaminato) ethylene] (b)were synthesized and characterized by X-ray crystallography. Both of them have distorted rectangular pyramidal geometry around Cu(Ⅱ). The complete series of complexes show bridging phenoxo groups between the copper centers, together with hydroxo-bridges in these complexes. The complexes have also been characterized by elemental analysis, IR, TG-DTA, and electrochemical results.     

Syntheses,structure and photoluminescent properties of lanthanide oxalatosulfocarboxylate coordination polymers

Hydrothermal reactions of oxalic acid(H2ox) and 2-sulfobenzoic acid(H2L) with lanthanide oxide or hydroxide yielded five lanthanide oxalatosulfocarboxylates.They have a general formula [Ln2L2(ox)(H2O)6]n[Ln = La(1),Nd(2),Eu(3),Gd(4),Tb(5)].Their structures were characterized by single crystal X-ray diffraction,powder X-ray diffraction(PXRD),infrared(IR) spectroscopy,elemental analysis(EA),and thermogravimetric analysis(TGA).1-5 are isostructural coordination polymers and feature one-dimensional(1D) chains,which are extended into 3D supramolecular frameworks through inter-chain hydrogen bonds between coordinated H2O donors and oxygen acceptors from carboxylate,sulfonate and oxalate groups.In addition,the solid-state photoluminescence properties of the Nd(2),Eu(3) and Tb(5) derivatives have been measured at room temperature.The Eu and Tb-containing coordination polymers(CPs) exhibit intense red and green luminescence emissions,respectively,with lifetimes in the order of millisecond.     

Synthesis and relaxivity of polycarboxylic hydrazone rare earth complexes——Relaxivity of α-oxo-pentanedioic acid benzoyl hydrazone Gd-complexes

Synthesis of ligand, α-oxo-pentanedioic acid benzoyl hydrazone (H₂LPB), and its six rare earth (La, Pr, Nd, Sm, Gd and Er) complexes are reported. The composition and the properties of the complexes were characterized by element analysis, thermal analysis, UV, IR and¹H NMR spectra. Besides, relaxivity (R ₁) of Gd-complex has been determined by INVREC.Au program, using inversion recovery pulse sequences, R₁=8.05 mmol · L⁻¹ · s⁻¹. The acute toxicity of Gd-complex in animal has also been tested, and the median lethal dose (LD₅₀) is equal to (468.2±30) mg/kg.     

三甘双酰氮甲基苯胺稀土高氯酸盐配合物的合成及表征

在非水介质中由轻稀土高氯酸盐与配体三甘双酰氮甲基苯胺(L)形成的6种具有稀土特征颜色的固体配合物,通式为[Ln(L)2(H2O)n](C1O4)3(Ln=La,Pr,Nd,Sm时,n=2;Ln=Eu,Tb时,n=1;不包括Pm),在这些新配合物中,配体L表现为四齿配位行为.     

Syntheses, characterization, crystal structure and magnetic properties of copper(Ⅱ)α, β-unsaturated carboxylate complexes with trimethyl phosphate

Two ternary complexes Cu2A4[OP(OCH₃)₃]₂ (A represents CH₂== CH—COO- and CH₂== C(CH₃)—COO-) have been synthesized, and elemental analyses, IR, ESR, electronic reflectance spectra and magnetic studies were carried out. The single crystal X-ray diffraction shows that Cu₂[CH₂== C(CH₃)—COO]₄[OP(OCH₃)₃]₂ is triclinic, with space group P1, a = 1.05128(13), b = 1.7559(5), c = 1.94479(3) nm, α = 91.263(14)°, β = 102.559(6)°, γ = 106.339(13)°, Z = 4 and R = 0.0668. Two copper(Ⅱ) atoms are bridged by four a -methacrylate groups, and each copper(Ⅱ) atom is coordinated with a trimethyl phosphate molecule in the axial position, forming a distorted square pyramidal configuration. The symmetric center is between the two copper(Ⅱ) atoms, and the Cu-Cu bond distance is 0.26098(6) nm. The Cu-Cu distance and magnetic studies suggest that there exist antiferromagnetic interactions between the two copper(Ⅱ) atoms.     

Rate constants for the reaction of ozone with <Emphasis Type="Italic">n</Emphasis>-butyl, <Emphasis Type="Italic">s</Emphasis>-butyl and <Emphasis Type="Italic">t</Emphasis>-butyl methyl sulfides

The rate constants for the ozone reactions with n-butyl methyl sulfide （n-BMS, CHaCH2CH2CH2SCH3）, sec-butyl methyl sulfide （s-BMS, CH3CH2（CH3）CHSCHa） and tert-butyl methyl sulfide （t-BMS, （CH3）3CSCH3） were measured using our smog chamber under supposedly pseudo-first-order conditions at 30002 K and 760 Torr. The experimental determined rate constants for n-butyl, s-butyl and t-butyl methyl sulfide are （1.23 ± 0.06）×10-19, （5.08 ± 0.19）×10-20 and （2.26 ± 0.14）×10-20 cm3 molecule-1· s-1, respectively. The reactivity-structure relationship of the reactions was discussed and used to illustrate the mechanism of the ozone reaction with thioethers. The results enrich the kinetics data of atmospheric chemistry.