New dicationic derivatives of dibenzotetraaza[14]annulene: tuning DNA-binding properties

Four new water-soluble derivatives of dibenzotetraaza[14]annulene have been synthesized, bearing meso substituents with different structures and dimensions: 3-(N,N,N-trimethylammonium)propyl, 3-(N-pyridinium-1-yl)propyl, 2-[3-(N,N,N-trimethylammonium)propoxy]benzoyl, and 2-[3-(N-pyridinium-1-yl)propoxy]benzoyl. The crystal structures of 3-(trimethylammonium)propyl and (N,N,N-trimethylammonium)propoxy]benzoyl derivatives were determined by single crystal X-ray analysis. According to the UV-vis titrations, thermal denaturation experiments, and ethidium bromide displacement assays, all compounds presented here interact strongly with double stranded (ct)-DNA. The product equipped with 3-(trimethylammonium)propyl pendant groups and two positive charges interacts with DNA in one dominant binding mode, whereas the other three derivatives revealed more complex mixed-type interactions. The results have been discussed in terms of dimensions, geometry, and electronic properties of the evaluated compounds, on the basis of corresponding crystallographic data.     

New lacunar-type and pendant groups containing derivatives of β-unsubstituted dibenzotetraaza[14]annulenes—syntheses and crystal structures

Three new lacunar-type derivatives of β-unsubstituted dibenzotetraaza[14]annulene have been synthesized along with a range of their open-chain pendant group containing counterparts. The crystal structures of two representative products have been determined and the noncovalent interactions explored. A number of C-H?π and π?π interactions involving aliphatic chains and aromatic regions of the macrocycle have been evidenced. The relative ease and high yield of lacunization are suggested to be largely due to self-assembly processes, driven by favorable noncovalent interactions between reacting units.     

Lacunar derivatives of dibenzotetraaza[14]annulene: synthesis and crystal structure of new receptors produced via bis-alkylation of the macrocyclic precursor

The bis(2-hydroxybenzoyl) derivative of dibenzotetraaza[14]annulene was employed as a substrate for producing new lacunar-type receptors. Alkylation of both phenolic OH groups using aliphatic dibromides and ditosylates efficiently leads to the expected bridged products without recourse to a high dilution procedure. Four new dibenzotetraaza[14]annulene-based lacunar receptors, and one unbridged open-chain bis-octoxy analogue have been synthesized. Synthetic procedures, analytical and spectroscopic characterization are reported. Conformations of the macrocyclic rings in the products as well as non-covalent interactions are discussed on the basis of their crystal structures.     

A new liquid crystalline derivative of dibenzotetraaza[14]annulene: synthesis, characterization and the preliminary evaluation of mesomorphic properties

A new dibenzotetraaza[14]annulene ligand has been synthesized that contains two 2-hydroxybenzoyl and four 3,7-dimethyloctyloxy peripheral substituents. Its mesomorphic textures were observed by means of a polarizing optical microscopy.     

5，14－二氢－6，8，15，17－四甲基二苯并［b，i］［1，4，8，11］四氮杂［14］轮烯金属配合物的合成和反应性研究

合成了二苯并四氮杂［１４］轮烯金属配合物ＴＭＴＡＡＮｉ（Ⅱ），ＴＭＴＡＡＣｕ（Ⅱ）和ＴＭＴＡＡＶ＝Ｏ，通过ＴＭＴＡＡＭ（Ⅱ）分子中金属离子Ｍ（Ⅱ）对位碳原子上发生酰化反应，获得了十个酰化产物，用元素分析，ＩＲ，ＵＶ，１￣ＨＮＭＲ，（１９）￣ＦＮＭＲ和ＥＰＲ等进行了表征。酰化反应的发生说明了这类金属配合物具有类芳香性，并为改善这类大环金属配合物的光－电性能提供了良好的途径。     

F and OH induced monodeprotonation of a lacunar cationic dibenzotetraaza[14]annulene: experimental evidence of tautomerism in a monoanionic macrocycle

A search for selective receptors of anions resulted in a new lacunar cationic derivative of dibenzotetraaza[14]annulene (DBTAA) being synthesized and its crystal structure determined. UV-vis, fluorescence and preliminary ¹H NMR studies of anion binding abilities revealed that under the influence of F⁻ and OH⁻, deprotonation of the macrocycle takes place leading to a zwitterionic species containing a monoanionic DBTAA core and a positively charged quaternized amine nitrogen. The tautomerism of the remaining single NH hydrogen is discussed on the basis of ¹H NMR experiments and DFT calculations.     

Spectral and Electrochemical Characterization of Dibenzotetraaza[14]annulenes

The UV/Vis absorption spectra and cyclic voltammograms (CV) of the Cu(II) and Ni(II) complexes of γ,γ'-alkoxycarbonyl derivatives of α,α'- diphenyldibenzo-tetraaza[14]annulene are analyzed and compared. The observed ratio of absorption intensities at the peaks of π-π* transitions is linearly correlated with the difference of HOMO and LUMO energy levels of the substituents. Moreover, the measured values of the mid-peak potential of metal redox reactions on a Pt electrode in DMF are linearly correlated with the ionization potential values of the appropriate substituents.     

Tuning the mesomorphic properties of liquid-crystalline dibenzotetraaza[14]annulenes — discotic nematic phases of tetraalkoxy-substituted derivatives

A homologous series of five tetrasubstituted dibenzotetraaza[14]annulene-based discotic mesogens was prepared and studied using polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). A nematic phase was identified for the product bearing two peripheral isobutoxy and two dodecyloxy substituents.     

A convenient and efficient one-pot method for the synthesis of novel acridine-calix[4]arene derivatives as new DNA binding agents via multicomponent reaction

A new approach is applied for the synthesis of novel acridine-calix[4]arene derivatives via a multicomponent reaction. These compounds have been characterised by ¹H NMR, ¹³C NMR and HR-MS. Our binding studies between acridine-functionalised calix[4]arenes and calf thymus DNA (CT-DNA) via fluorescence titration show that these compounds have a good affinity to CT-DNA.     

Synthesis,characterization, and crystal structures of N-functionalized diiron azadithiolate complexes related to the active site of [FeFe]-hydrogenases

A series of N-functionalized diiron azadithiolate complexes, [(µ-SCH₂)₂NCH₂CO₂Me]Fe₂(CO)_5?L [L?=?CO (1); PPh₃ (2); Ph₂PCH₂PPh₂ (3)], as active site models of [FeFe]-hydrogenases has been prepared and characterized. While 1 was prepared by a sequential reaction of (µ-HS)₂Fe₂(CO)₆ with two equiv. of aqueous HCHO, followed by treatment of (µ-HOCH₂S)₂Fe₂(CO)₆ with one equiv. of H₂NCH₂CO₂Me in 46% yield; 2 and 3 were prepared by a carbonyl substitution reaction of 1 with PPh₃ or Ph₂PCH₂PPh₂ in the presence of Me₃NO?·?2H₂O in 90% and 85% yields, respectively. The crystal structures of 1 and 2 revealed that the substituent attached to the bridgehead nitrogen occupies an equatorial position and the PPh₃ ligand resides in an axial position of the square pyramid of Fe2.     

二苯并四氮杂[14]轮烯金属配合物电子结构和性质

用量子化学半经验方法和从头算对二苯并四氮杂[14]轮烯（Tmtaa)离子及其金属配合物的电子结构进行了详细的研究.讨论了轮烯金属配合物合成的模板效应及金属离子半径大小对模板效应的影响作用,对其亲电取代反应的活性位置作了相应理论解释.依据理论计算结果指导了轮烯配合物的定向亲电取代反应及新金属配合物的合成尝试,理论计算与实验事实基本一致.Tmtaa-Ni等配合物及其亲电取代反应产物的1HNMR谱、19FNMR谱表明金属配合物中金属离子对位C7、C16上的H原子被取代,与理论计算结果十分一致.     

New tetraaza[14]annulene receptors derived from 2,3-diaminonaphthalene: synthesis and crystal structures

The first synthesis of the bis(2-hydroxybenzoyl)dinaphthotetraaza[14]annulene ligand and its O,O-bis-alkylated derivatives containing a decanedioxy bridging moiety, pendant bis-alkoxy groups as well as dicationic butoxypyridinium substituents is reported. The synthetic procedures, full analytical and spectroscopic characterisation (NMR, MS and IR) and crystal structures of the new products are described. The crystal structures show that naphthylene moieties incorporated into the investigated derivatives provide additional opportunities for non-covalent interactions between the molecules.     

Synthesis,structure, DNA binding and cleavage ability of a new copper ciprofloxacin complex

The structure of 1 consists of [Cu(HCp)(phen)(H₂O)]²⁺ (HCp is ciprofloxacin and phen is 1,10-phenanthroline), two acetates, and four free water molecules. In each cation, copper displays a distorted square pyramid, coordinated to ring 3-carboxylate and 4-oxo oxygen from HCp, two nitrogens from phen, and one water molecule. There are five water molecules in each discrete complex with one coordinated to Cu center, and the other four linked to each other by intermolecular hydrogen bonds. Two uncoordinated acetates make the compound neutral. The complex exhibits higher DNA binding compared to HCp at the same conditions by fluorescence and viscosity measurements. Combining its structure with the DNA-binding result, the binding mechanism may be explained by intercalation. Moreover, 1 shows significant cleavage of DNA in the presence of a reducing agent, such as ascorbate by gel electrophoresis using supercoiled pBR322 DNA in Tris-HCl buffer (pH 7.4). The complex also has a higher activity against Gram-positive bacteria Staphylococcus aureus and Gram-negative bacteria Klebsiella pneumoniae than HCp.     

含苯并噻唑基的硫桥杯芳烃衍生物的合成及结构

在碳酸钾存在下, 对叔丁基硫桥杯芳烃(1)分别与端基二溴代烷和碘甲烷反应, 生成硫桥杯芳烃衍生物2 和3, 它们分别与过量的2-巯基苯并噻唑在碳酸钾存在下反应, 生成含苯并噻唑基的硫桥杯芳烃衍生物5a～5d. 通过 1H NMR, 13C NMR, IR, MS和元素分析等手段对产物进行了表征. 同时, 采用X射线衍射分析确定了硫桥杯芳烃5b的晶体结构.     

Synthesis, structural characterization, and anion binding ability of sterically congested adamantane-calix[4]pyrroles and adamantane-calixphyrins

Novel adamantane derivatives of calix[4]pyrroles 4-8 and calixphyrin 9 have been synthesized. The structure of 8 has been characterized by X-ray powder diffraction and the structure of 9 by single crystal X-ray analysis. Whereas calixphyrin 9 does not bind anions, analogous calyx[4]pyrrole 8 forms a complex with Cl⁻ in the DMSO solution and in the solid state. The solid state complexation has been accomplished on grinding in a mill, which is the first example of complex formation with an anion in the solid state.     

Synthesis,crystal structures,DNA binding and oxidative cleavage studies of copper(II) complexes of N2S2 tetradentate ligands

Two new copper(II) complexes with aminothioether ligands, [Cu(L¹)(ClO₄)](ClO₄) · 0.5H₂O (1) and [Cu(L²)(H₂O)](ClO₄)₂ · H₂O (2) (L¹ = 2-benzyl-1,3-bis(aminoethylthio)propane and L² = 2-(4-butylbenzyl)-1,3-bis(aminoethylthio)propane), have been synthesized and characterized. The single crystal X-ray diffraction analysis reveals that both 1 and 2 adopt distorted square pyramidal geometries. The binding modes of both complexes with calf thymus DNA were investigated by UV–Vis and CD spectroscopies. The results show that both complexes mainly adopt an electrostatic attraction binding mode with DNA and the binding constants are (1.62 ± 0.02) × 10³ and (2.02 ± 0.02) × 10³ M⁻¹, respectively. Both complexes are able to cleave pBR322 plasmid DNA efficiently in the presence of ascorbic acid and the activity of 2 is higher than that of 1. The DNA cleavage by 1 and 2 were inhibited strongly in the presence of DMSO and tert-butyl alcohol, which suggests that hydroxyl radicals are the reactive oxygen species for the cleavage.     

Synthesis,crystal structures and complexing ability of difunctionalized copillar[5]arene Schiff bases

An efficient method for the synthesis of some difunctionalized copillar[5]arene Schiff bases from condensation of salicylaldehyde and its 5-chloro, 5-bromo, 3,5-di(t-butyl) substituted derivatives with corresponding diamino-functionalized copillar[5]arene, which were prepared by Gabriel reaction according to the reported method. Single-crystals of six copillar[5]arenes were determined by X-ray diffraction. An ORTEP of compounds showed that the two chains units of Schiff base exist in the outside of the cavity of pillar[5]arene. Furthermore, the complexing ability of these Schiff bases to transition metal ions were investigated by UV and fluorescence spectroscopy.