Synthesis,characterization and biological studies of alkenyl‐substituted titanocene(IV) carboxylate complexes

The carboxylate compounds [Ti(η⁵‐C₅H₅)(η⁵‐C₅H₄{CMe₂(CH₂CH₂CH?CH₂)})(O₂CCH₂SXyl)₂] (2; Xyl = 3,5‐Me₂C₆H₃) and [Ti(η⁵‐C₅H₅)(η⁵‐C₅H₄{CMe₂(CH₂CH₂CH?CH₂)})(O₂CCH₂SMesl)₂] (3; Mes 1 = 2,4,6‐Me₃C₆H₂) were synthesized by the reaction of [Ti(η⁵‐C₅H₅)(η⁵‐C₅H₄{CMe₂(CH₂CH₂CH?CH₂)})Cl₂] (1) with 2 equivalents of xylylthioacetic acid or mesitylthioacetic acid, respectively. Compounds 2 and 3 were characterized by spectroscopic methods. The cytotoxic activity of 1–3 was tested against human tumor cell lines from four different histogenic origins—8505C (anaplastic thyroid cancer), DLD‐1 (colon cancer) and the cisplatin sensitive A253 (head and neck cancer) and A549 (lung carcinoma)—and compared with those of the reference complex [Ti(η⁵‐C₅H₅)₂Cl₂] (R1) and cisplatin. Surprisingly, the cytotoxic activities of the carboxylate derivatives were lower than those of their corresponding dichloride analogue (1). However, complexes 1–3 were more active than titanocene dichloride against all the studied cells with the exception of complex 2 against A253 and A549 cell lines. DNA‐interaction tests were also carried out. Solutions of all the studied complexes were treated with different concentrations of fish sperm DNA, observing modifications of the UV spectra with intrinsic binding constants of 2.99 × 10⁵, 2.45 × 10⁵, and 2.35 × 10⁵ M ^?1 for 1–3. Structural studies based on density functional theory calculations of 2 and 3 were also carried out. Copyright © 2010 John Wiley & Sons, Ltd.     

溴钼环卡宾配合物的合成及结构

本文以三羰基戊二烯基钼负离子锂盐代替钠盐,成功地制得了溴钼环卡宾配合物。用X射线衍射测定了其晶体,晶体属正交晶系,空间群P2~12~12~1,晶体学数据:a=0.8600(2),b=1.4775(3),c=1.9900(7)nm;V=2.529nm^3,Z=8,D~x=1.93g.cm^-^3;μ=41.3cm^-^1,F(000)=1424。偏差因子R=0.055,R~w=0.060。     

Syntheses and structures of one CuI‐containing coordination polymer and two macrocyclic supramolecular complexes based on flexible 1,3,4‐oxadiazole‐containing ligands

Three coordination complexes with Cu^I centres have been prepared using the symmetrical flexible organic ligands 1,3‐bis{[5‐(quinolin‐2‐yl)‐1,3,4‐oxadiazol‐2‐yl]sulfanyl}propane (L1) and 1,4‐bis{[5‐(quinolin‐2‐yl)‐1,3,4‐oxadiazol‐2‐yl]sulfanyl}butane (L2). Crystallization of L1 with Cu(SO₃CF₃)₂ and of L2 with Cu(BF₄)₂ and Cu(ClO₄)₂ in a CH₂Cl₂/CH₃OH mixed‐solvent system at room temperature afforded the coordination complexes catena‐poly[[copper(I)‐μ‐1,3‐bis{[5‐(quinolin‐2‐yl)‐1,3,4‐oxadiazol‐2‐yl]sulfanyl}propane] methanesulfonate dichloromethane 0.6‐solvate], {[Cu(C₂₅H₁₈N₆O₂S₂)](CF₃SO₃)·0.6CH₂Cl₂}_n, (I), bis(μ‐1,4‐bis{[5‐(quinolin‐2‐yl)‐1,3,4‐oxadiazol‐2‐yl]sulfanyl}butane)dicopper(I) bis(tetrafluoridoborate)–dichloromethane–methanol (1/1.5/1), [Cu₂(C₂₆H₂₀N₆O₂S₂)₂](BF₄)₂·1.5CH₂Cl₂·CH₃OH, (II), and bis(μ‐1,4‐bis{[5‐(quinolin‐2‐yl)‐1,3,4‐oxadiazol‐2‐yl]sulfanyl}butane)dicopper(I) bis(perchlorate)–dichloromethane–methanol (1/2/1), [Cu₂(C₂₆H₂₀N₆O₂S₂)₂](ClO₄)₂·2CH₂Cl₂·CH₃OH, (III). Under the control of the dumbbell‐shaped CF₃SO₃⁻ anion, complex (I) forms a one‐dimensional chain and neighbouring chains form a spiral double chain. Under the control of the regular tetrahedron‐shaped BF₄⁻ and ClO₄⁻ anions, complexes (II) and (III) have been obtained as bimetallic rings, which further interact viaπ–π interactions to form two‐dimensional networks. The anions play a decisive role in determining the arrangement of these discrete molecular complexes in the solid state.     

Synthesis and structures of two supramolecular complexes constructed via hydrogen bond linking

Two supramolecular complexes,[Ni(rac-L)]3[CrO4]2[ClO4]2-4H2O (1) and [meso-H2L]0.5[VO3]-0.16H2O (2) (L= 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetra-decane),have been prepared in an aqueous solu-tion,and detected by elemental analysis,IR,TG,and single crystal X-ray diffraction analyses. Com-pound 1 shows a one-dimensional hexagonal prism formed by the hydrogen bonding interactions between the secondary amines of rac-L and CrO42-anion/water molecules. Compound 2 displays a three-dimensional structur...     

Crystallographic report: Tris(η5‐cyclopentadienyl)‐tetrahydrofuran‐praseodymium

The title compound is mononuclear with three η⁵‐cyclopentadienyl ligands and one tetrahydrofuran ligand. If the centroids of the cyclopentadienyl ligands are taken as the point of binding to praseodymium, then the environment about the metal centre is considered as a distorted tetrahedron. Copyright © 2003 John Wiley & Sons, Ltd.     

Crystallographic report: Bis(µ2‐chloro)‐{bis(diethylether)‐lithium}‐bis(η5‐pentamethyl‐cyclopentadienyl)samarium(III)

The structure is mononuclear with samarium bound by two η⁵‐cyclopentadienyl ligands and two chloride ligands, the latter of which bridge to a doubly ether‐solvated lithium centre. Copyright © 2004 John Wiley & Sons, Ltd.     

Crystallographic report: Bis(η5‐methyl‐cyclopentadienyl)‐bis(cyanato)‐vanadium(IV)

The crystal structure of the first cyclopentadienyl vanadium(IV) pseudohalide complex, (η⁵‐C₅H₄CH₃)₂V(NCO)₂, was determined. The molecule has a typical bent metallocene structure in which two η⁵‐bonded methyl‐cyclopentadienyl rings and two nitrogen atoms of cyanato ligands occupy the pseudotetrahedral coordination sites around the vanadium(IV) center. Copyright © 2005 John Wiley & Sons, Ltd.     

Syntheses,Structures and Properties of Four New Transitional Metal Complexes Based on Benzotriazole‐5‐carboxylic Acid

Four new complexes, [Zn(btca)(2,2′‐bpy)] ( 1 ), [Mn(btca)(2,2′‐bpy)] ( 2 ), [Co(btca)(phen)] ( 3 ), and [Cu(btca)(phen)] ( 4 ), (H₂btca=benzotriazole‐5‐carboxylic acid, 2,2′‐bpy=2,2′‐bipyridine, phen=1,10‐phenanthroline), were successfully synthesized and characterized by elemental analysis, single crystal X‐ray diffraction, and IR spectroscopy. Complexes 1 – 4 crystallize in the orthorhombic system with space group of Pbca and show similar 2D layers, which are interlinked to supramolecular networks by π‐π stacking interactions. Furthermore, TGA curves show that complexes 1 – 4 have good thermal stability. Solid‐state fluorescent property of complex 1 was also investigated at room temperature.     

Syntheses,supramolecular structures and properties of six coordination complexes based on 5-sulfosalicylic acid and bipyridyl-like chelates

Six new complexes constructed by 5-sulfosalicylic acid and bipyridyl-like ligands (2,2′-bipy and 1,10-phen), namely [Cu₄(OH)₂(ssal)₂(phen)₄ · 7H₂O] (1), [Cu₄(OH)₂(ssal)₂(bipy)₄ · 2H₂O] (2), [Cd(Hssal)(bipy)] (3), [Cd(HL)₂(phen)₂] (4), [Cr(ssal)(bipy)(H₂O)₂ · 2H₂O] (5) and [Cr(ssal)(phen)₂] (6) (H₃ssal = 5-sulfosalicylic acid, H₂L = p-hydroxybenzenesulfonic acid, bipy = 2,2′-bipy, phen = 1,10-phen) were prepared under hydrothermal conditions and their structures were determined by single-crystal X-ray diffraction. Complexes 1 and 2 are both tetranuclear copper complexes with a stepped topology. In complex 3, a new coordination mode of the Hssal²⁻ group is reported in this work. During the synthetic process of complex 4, in situ decarboxylation of 5-sulfosalicylic acid into p-hydroxybenzenesulfonic acid is involved. Two chromium 5-sulfosalicylates (5 and 6) are reported for the first time. These new complexes display different supramolecular structures by O–H?O, C–H?O hydrogen bonds as well as π?π, C–H?π and O?π interactions. The results of magnetic determination show that ferromagnetic interactions exist in complex 1, however, antiferromagnetic interactions exist in 2.     

Syntheses and crystal structures of diorganotin(IV) bis(2‐pyridinethiolato‐N‐oxide) complexes

The complexes di‐n‐butyldi(2‐pyridinethiolato‐N‐oxide)tin(IV) (1), diphenyldi(2‐pyridinethiolato‐N‐oxide)tin(IV) ( 2 ) and dibenzyldi(2‐pyridinethiolato‐N‐oxide)tin(IV) ( 3 ) are synthesized and characterized by elemental analyses, IR, ¹H, ¹³C, ¹¹⁹Sn NMR spectroscopy, and their structures are determined by X‐ray crystallography. In complex 1 the coordination geometry at tin is a skew‐trapezoidal bipyramid, with cis‐S,S and cis‐O,O atoms occupying the trapezoidal plane and two n‐butyl groups occupying the apical positions, which also exhibits strong π–π stacking interactions. In complexes 2 and 3 the geometry at tin is distorted cis‐octahedral, with cis‐O,O and cis‐C,C atoms occupying the equatorial plane and trans‐S,S atoms occupying the apical positions. Their in vitro cytotoxicity against two human tumour cell lines, MCF‐7 and WiDr is reported. The ID₅₀ values found are comparable to those found for cis‐platin, but lower than for many other diorganotin compounds. Copyright © 2003 John Wiley & Sons, Ltd.     

Two silver(I) complexes with bis(benzimidazole)‐2‐oxopropane ligands: Syntheses,crystal structures and DNA binding studies

Two Ag(I) complexes, [Ag₂(bobb)₂]⋅(NO₃)₂ ( 1 ) and [Ag₂(crotonate)₂(aobb)]_n ( 2 ) (bobb =1,3‐bis(1‐benzylbenzimidazol‐2‐yl)‐2‐oxapropane; aobb =1,3‐bis(1‐allylbenzimidazol‐2‐yl)‐2‐oxopropane), have been synthesized and characterized using elemental analysis, electrical conductivities, infrared and UV–visible spectral measurements and single‐crystal X‐ray diffraction. Complex 1 is binuclear and three‐coordinated by two N atoms from two bobb ligands, while complex 2 is a unique metal organic compound with diamond‐like multinuclear Ag centers with each Ag bridged by two aobb ligands and two crotonate ions to form one‐dimensional single polymer chain structures and extended into two‐dimensional frameworks through π–π and intermolecular C─H⋅⋅⋅O hydrogen bonds. The adjacent Ag(I) centers are bridged by allyl from aobb which is not only a σ‐bonding ligand, but also a π‐acid ligand. The DNA binding modes of complexes 1 and 2 were investigated using electronic absorption titration, fluorescence spectra and viscosity measurements. The results suggest that the two complexes bind to DNA via an intercalative mode, and their binding affinity for DNA follows the order 2  >  1 . This is due to the chelating effects which can enhance the planar functionality of the metal complexes.     

Two‐dimensional coordination polymeric structures in caesium complexes with ring‐substituted phenoxyacetic acids

The two‐dimensional polymeric structures of the caesium complexes with the phenoxyacetic acid analogues (4‐fluorophenoxy)acetic acid, (3‐chloro‐2‐methylphenoxy)acetic acid and the herbicidally active (2,4‐dichlorophenoxy)acetic acid (2,4‐D), namely poly[[μ₅‐(4‐fluorophenoxy)acetato][μ₄‐(4‐fluorophenoxy)acetato]dicaesium], [Cs₂(C₈H₆FO₃)₂]_n, (I), poly[aqua[μ₅‐(3‐chloro‐2‐methylphenoxy)acetato]caesium], [Cs(C₉H₈ClO₃)(H₂O)]_n, (II), and poly[[μ₇‐(2,4‐dichlorophenoxy)acetato][(2,4‐dichlorphenoxy)acetic acid]caesium], [Cs(C₈H₅Cl₂O₃)(C₈H₆Cl₂O₃)]_n, (III), are described. In (I), the Cs⁺ cations of the two individual irregular coordination polyhedra in the asymmetric unit (one CsO₇ and the other CsO₈) are linked by bridging carboxylate O‐atom donors from the two ligand molecules, both of which are involved in bidentate chelate O_carboxy,O_phenoxy interactions, while only one has a bidentate carboxylate O,O′‐chelate interaction. Polymeric extension is achieved through a number of carboxylate O‐atom bridges, with a minimum Cs...Cs separation of 4.3231 (9) Å, giving layers which lie parallel to (001). In hydrated complex (II), the irregular nine‐coordination about the Cs⁺ cation comprises a single monodentate water molecule, a bidentate O_carboxy,O_phenoxy chelate interaction and six bridging carboxylate O‐atom bonding interactions, giving a Cs...Cs separation of 4.2473 (3) Å. The water molecule forms intralayer hydrogen bonds within the two‐dimensional layers, which lie parallel to (100). In complex (III), the irregular centrosymmetric CsO₆Cl₂ coordination environment comprises two O‐atom donors and two ring‐substituted Cl‐atom donors from two hydrogen bis[(2,4‐dichlorophenoxy)acetate] ligand species in a bidentate chelate mode, and four O‐atom donors from bridging carboxyl groups. The duplex ligand species lie across crystallographic inversion centres, linked through a short O—H...O hydrogen bond involving the single acid H atom. Structure extension gives layers which lie parallel to (001). The present set of structures of Cs salts of phenoxyacetic acids show previously demonstrated trends among the alkali metal salts of simple benzoic acids with no stereochemically favourable interactive substituent groups for formation of two‐dimensional coordination polymers.     

2‐Amino‐5‐iodopyridinium bromide hemihydrate and 2‐amino‐5‐iodopyridinium chloride monohydrate

The hydrobromide and hydrochloride salts of 2‐amino‐5‐iodopyridine were prepared from aqueous solutions. The hydrobromide salt, C₅H₆IN₂⁺·Br⁻·0.5H₂O, crystallizes as a hemihydrate, and exhibits hydrogen bonding and π‐stacking which stabilize the crystal structure. The hydrochloride salt, C₅H₆IN₂⁺·Cl⁻·H₂O·0.375HCl, crystallized as the hydrate and exhibits similar hydrogen bonding and π‐stacking in the lattice. The most interesting feature of the hydrochloride salt is the presence of an additional fractional HCl molecule which introduces disorder in the location of the water molecule. The additional proton from the fractional HCl molecule is accounted for by the presence of a partial hydronium ion on one of the water sites.     

Synthesis,structure and in vitro cytotoxicity testing of some 1,3,4‐oxadiazoline derivatives from 2‐hydroxy‐5‐iodobenzoic acid

The syntheses of nine new 5‐iodosalicylic acid‐based 1,3,4‐oxadiazoline derivatives starting from methyl salicylate are described. These compounds are 2‐[4‐acetyl‐5‐methyl‐5‐(3‐nitrophenyl)‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate ( 6a ), 2‐[4‐acetyl‐5‐methyl‐5‐(4‐nitrophenyl)‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate ( 6b ), 2‐(4‐acetyl‐5‐methyl‐5‐phenyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl)‐4‐iodophenyl acetate, C₁₉H₁₇IN₂O₄ ( 6c ), 2‐[4‐acetyl‐5‐(4‐fluorophenyl)‐5‐methyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate, C₁₉H₁₆FIN₂O₄ ( 6d ), 2‐[4‐acetyl‐5‐(4‐chlorophenyl)‐5‐methyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate, C₁₉H₁₆ClIN₂O₄ ( 6e ), 2‐[4‐acetyl‐5‐(3‐bromophenyl)‐5‐methyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate ( 6f ), 2‐[4‐acetyl‐5‐(4‐bromophenyl)‐5‐methyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate ( 6g ), 2‐[4‐acetyl‐5‐methyl‐5‐(4‐methylphenyl)‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate ( 6h ) and 2‐[5‐(4‐acetamidophenyl)‐4‐acetyl‐5‐methyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate ( 6i ). The compounds were characterized by mass, ¹H NMR and ¹³C NMR spectroscopies. Single‐crystal X‐ray diffraction studies were also carried out for 6c , 6d and 6e . Compounds 6c and 6d are isomorphous, with the 1,3,4‐oxadiazoline ring having an envelope conformation, where the disubstituted C atom is the flap. The packing is determined by C—H…O, C—H…π and I…π interactions. For 6e , the 1,3,4‐oxadiazoline ring is almost planar. In the packing, Cl…π interactions are observed, while the I atom is not involved in short interactions. Compounds 6d , 6e , 6f and 6h show good inhibiting abilities on the human cancer cell lines KB and Hep‐G2, with IC₅₀ values of 0.9–4.5 µM.     

Syntheses and structures of discrete copper(II) and cadmium(II) supramolecular complexes based on 1,4‐diacylthiosemicarbazone ligands

Thiosemicarbazides and their metal complexes have attracted considerable interest because of their biological activities and their flexibility, which allows the ligands to bend and rotate freely to accommodate the coordination geometries of various metal centres. Discrete copper(II) and cadmium(II) complexes have been prepared by crystallization of N‐[2‐(2‐hydroxybenzoyl)hydrazinecarbonothioyl]propanamide (H₃L) with Cu(CH₃COO)₂ or Cd(NO₃)₂ in a dimethylformamide/methanol mixed‐solvent system at room temperature, affording the complexes di‐μ‐acetato‐bis{μ₄‐1‐[(2‐oxidophenyl)carbonyl]‐2‐(propanamidomethanethioyl)hydrazine‐1,2‐diido}tetracopper(II) dimethylformamide disolvate, [Cu₄(C₁₁H₁₀N₃O₃S)₂(C₂H₃O₂)₂]·2C₃H₇NO, (I), and bis{μ₂‐[(2‐hydroxyphenyl)formamido](propanamidomethanethioyl)azanido}bis[(4,4′‐bipyridine)nitratocadmium(II)] dihydrate, [Cd₂(C₁₁H₁₂N₃O₃S)₂(NO₃)₂(C₁₀H₈N₂)₂]·2H₂O, (II). Complex (I) consists of four Cu^II cations, two μ₄‐bridging trianionic ligands and two μ₂‐bridging acetate ligands, while complex (II) is composed of two Cd^II cations, two μ₂‐bridging monoanionic ligands, two nitrate ligands and two 4,4′‐bipyridine ligands. These discrete complexes are connected by hydrogen bonds and van der Waals interactions to form a three‐dimensional supramolecular architecture. Compared with (I), the phenolic hydroxy group and hydrazide N atom of the thiosemicarbazide ligand of (II) are not involved in coordination and lead to a binuclear Cd^II complex. This different coordination mode may be attributed to the larger ionic radius of the Cd^II ion compared with the Cu^II ion.     

Construction of three types of lanthanide complexes based on 3,4‐dimethylbenzoic acid and 5,5′‐dimethyl‐2,2′‐bipyridine: Syntheses,Structures, Thermodynamic properties,Luminescence, and Bacteriostatic activities

Three novel lanthanide complexes [Er (3,4‐DMBA)₃(5,5′‐DM‐2,2′‐bipy)(H₂O)] ( 1 ); [Tb₂ (3,4‐DMBA)₆(5,5′‐DM‐2,2′‐bipy)₂(H₂O)] ( 2 ); [Eu (3,4‐DMBA)₃(3,4‐DMHBA)(5,5′‐DM‐2,2′‐bipy)]₂ ( 3 ) (3,4‐DMHBA = 3,4‐dimethylbenzoic acid, 5,5′‐DM‐2,2′‐bipy =5,5′‐dimethyl‐2,2′‐bipyridine) were successfully synthesized via conventional solution method at room temperature and structurally characterized by single crystal diffraction. The structures of the complexes 1 – 3 were confirmed on the basis of elemental analysis, coordination titration analysis, IR and XRD. The molecular structures of complexes 2 and 3 are very particular: complex 2 has two same central metal ions but each metal ion has different coordination environment; in structure of the complex 3 , there are eight carboxylic acid ligands coordinated to the central metal ions, which have rarely been reported previously. The thermal decomposition mechanism of complexes 1 – 3 were investigated by the technology of simultaneous TG/DSC‐FTIR. The heat capacities of the complexes were recorded by means of DSC over the range of from 253.15 K to 345.15 K. The thermodynamic parameters, the smoothed values of heat capacities, enthalpy (H_T‐H_298.15K) and entropy (S_T‐S_298.15K) were also calculated. The bacteriostatic activities of the complexes were evaluated against Staphylococcus aureus, Escherichia coli and Candida albicans. What's more, the luminescence properties of complexes 2 and 3 were discussed, and their fluorescence lifetimes as well as the quantum yield of the Eu (III) were measured. To elucidate the energy transfer process of complexes 2 and 3, the energy levels of the relevant electronic states have been estimated.     

Synthese und Molekülstruktur von [1,3-(Me3Si)2C5H3](Me3SiC5H4)ZrCl2

Synthesis and Molecular Structure of [1,3-(Me₃Si)₂C₅H₃](Me₃SiC₅H₄)ZrCl₂ . The unsymmetrically substituted zirconocene dichloride was prepared by reaction of trimethylsilylcyclopentadienyl lithium and 1,3-bis(trimethylsilyl)cyclopentadienyl lithium with ZrCl₄ · 2 THF. The molecular structure was determined (P2₁/a; a = 1 357.9, b = 1 900.0, c = 1 043.2 pm, β = 105,16°). The Zr? Cl distance are remarkably short.     

Syntheses of 5‐Hexadecanolide, 6‐Acetoxy‐5‐hexadecanolide and Tanikolide

Total syntheses of 5‐hexadecanolide ( 1 ), 6‐acetoxy‐5‐hexadecanolide ( 2 ) and tanikolide ( 3 ) are described. 1‐Bromoundecane ( 4 ) and 5‐benzyl‐1‐pentanal ( 5 ) were chosen as starting materials. Wittig olefination and Grignard addition 4 and 5 afforded the 16‐carbon skeleton, which under went a series of functional group transformations to give δ‐lactonederivatives 1, 2 and 3.     

Syntheses and crystal structures of supramolecular compounds of tetranuclear ZrIV and HfIV aqua hydroxo complexes with macrocyclic cavitand cucurbituril

Slow evaporation of hydrochloric acid solutions of zirconium(iv) or hafnium(iv) oxochlorides and cucurbituril in air afforded compounds with composition [M₄(OH)₈(H₂O)₁₆]Cl₈·(C₃₆H₃₆N₂₄O₁₂)·16H₂O, where M = Zr (1) or Hf (2). According to the X-ray diffraction data, complexes 1 and 2 are isostructural. Their crystal structures can be described as packings of polymer chains consisting of alternating cucurbituril molecules and tetranuclear cations [M₄(OH)₈(H₂O)₁₆]⁸⁺ linked to each other via an extensive network of hydrogen bonds. Compound 2 is the first structurally characterized tetranuclear hafnium aqua complex.     

Construction of lanthanide complexes supported by 2,3‐dimethoxybenzoic acid and 5,5’‐dimethy‐2,2’‐bipyridine: crystal structures,thermoanalysis, magnetic and fluorescence properties

A series of novel trivalent lanthanide complexes, [Ln(2,3‐DMOBA)3(5,5′‐DM‐2,2′‐bipy)]2·C2H5OH (Ln = Eu(1), Sm(2), Gd(3), Ho(4) Er(5), Pr(6), Nd(7)) (2,3‐DMOBA = 2,3‐dimethoxybenzoate, 5,5′‐DM‐2,2′‐bipy = 5,5′‐dimethy‐2,2′‐bipyridine), have been successfully synthesized and structurally validated by single crystal diffraction. All complexes discussed herein feature a binuclear structure, and contain only one free ethanol molecule, which is interesting in the lanthanide complexes. The coordination number of center Ln3+ ions is nine, showing a distorted monocapped square anti‐prismatic coordination geometry. Through a pair of alternating identical C‐H···O hydrogen bonding interactions between two 2,3‐DMOBA ligands on the same lanthanum binuclear unit with 5,5′‐DM‐2,2′‐bipy ligands on two neighboring units, the binuclear complexes can form one‐ The thermal analysis of these complexes are investigated by TG‐DSC/FTIR, the result show that the decomposition process of complexes are mainly divided into four stages with the formation of the respective oxides. The visible light emission experiment of complex 1 is carried out, and the characteristic luminescence behavior of intense red light is exhibited. What'more, fluorescence lifetimes as well as the fluorescent quantum yield of complex 1 is calculated. And the magnetic properties of complexes 3–5 are also studied.