Synthesis and characterization of macrocyclic compounds with a hydroxyl functional group

A novel [1+1] Schiff-base macrocyclic compound 3 has been synthesized from precursor 1, 1,3-bis(2'-formylphenoxy)-2-propanol, and precursor 2, resorcinol-bis(4-aminophenyl)ether, via condensation and cyclizaction using Ba2+ as template. The macrocycle 3 was further reduced giving saturated macrocycle 4. The structures of 3 and 4 were characterized by elemental analysis, 1H NMR, IR, and MS spectra, and their structures were determined via single crystal X-ray diffraction studies. X-ray diffraction analysis revealed that the macrocyclic compound 3 has a folded conformation, and the corresponding reduced product 4 adopts a twisted and folded conformation due to its flexible nature.     

Synthesis, structures and reactivity of macrocyclic imidazolylboranes

New macrocyclic imidazolylboranes [imidazolylB(R¹)₂]_n, where selected carbon atoms of imidazolyl rings may bear substituents other than hydrogen, and where n=4 or 5, are obtained from 1-trimethysilylimidazoles and haloboranes XB(R¹)₂ by boron/silicon exchange using 2-bromoimidazole and benzimidazole. These macrocycles are formally zwitterionic and contain imidazolyl rings linked through their nitrogen atoms by BH₂, B(R¹)₂ or BR¹X units. Despite the sterical demand of these derivatives tetrameric macrocycles are formed. A new synthetic strategy to macrocyclic imidazolylboranes includes the preparation and cyclization of bis(imidazolyl)boronium chlorides. In addition dihaloboranes have been tested for cyclization to yield halogen-containing macrocycles. The new compounds are spectroscopically characterized and X-ray structure analyses of tetrameric- (2a) and pentameric 1-imidazolylborane (2a′), tetrameric 1-imidazolyldimethylborane (2b), tetrameric 1-(2-bromo)imidazolylborane (2d) and bis(2-bromoimidazolyl)boronium chloride (3d) are reported.     

Synthesis and structure of neutral double helicate

A new approach to generating supramolecular architectures,based on easy-to-prepare schiff base ligands,is described together with its application to the self-assembly of supramolecu-lar neutral double helicates.     

Synthesis and crystal structure of Mn(II) complexes with novel macrocyclic Schiff-base ligands containing piperazine moiety

A series of Mn(II) macrocyclic Schiff-base complexes [MnLⁿCl]⁺ (n = 1–4) have been prepared via the Mn(II) templated [1+1] cyclocondensation of 2,6-diacetylpyridine or 2,6-pyridinedicarbaldehyde with the symmetrical 1,4-bis(3-aminopropyl)piperazine or the novel asymmetrical N,N′(2-aminoethyl)(3-aminopropyl)piperazine linear amines containing piperazine moiety. The complexes have been characterized by elemental analyses, IR, FAB-MS, magnetic studies and conductivity measurements. The crystal structure of [MnL²(CH₃OH)Cl](ClO₄) and [MnL⁴Cl](PF₆) complexes have also been determined showing the metal ion in a N₄OCl pentagonal bipyramidal or N₄Cl highly distorted octahedral geometry, respectively.     

Synthesis, structural characterization and electrochemical studies of new macrocyclic Schiff base containing pyridine head and its metal complexes

A new macrocyclic ligand, 1,3,5-triaza-2,4:7,8:13,14-tribenzo-9,12-dioksa-cyclopentadeca-1,5-diene was synthesized by reaction of 2,6-diaminopyridine and 1,2-bis(2-carboxyaldehyde phenoxy)ethane. Then, its Cu(II), Ni(II), Pb(II), Co(III) and La(III) complexes were synthesized by the template effect by the reaction of 2,6-diaminopyridine and 1,2-bis(2-carboxyaldehyde phenoxy)ethane and Cu(NO₃)₂ · 3H₂O, Ni(NO₃)₂ · 6H₂O, Pb(NO₃)₂, Co(NO₃)₂ · 6H₂O, La(NO₃)₃ · 6H₂O, respectively. The ligand and its metal complexes have been characterized by elemental analysis, IR, ¹H and ¹³C NMR, UV-Vis spectra, magnetic susceptibility, thermal gravimetric analysis, conductivity measurements, mass spectra, and cyclic voltammetry. All complexes are diamagnetic and Cu(II) complex is binuclear. The Co(II) was oxidized to Co(III). The comparative electrochemical studies show that the nickel complex exhibited a quasi-reversible one-electron reduction process, while copper and cobalt complexes gave irreversible reduction processes in DMSO solution.     

Synthesis of a new 24-membered tetramide macrocycle and X-ray crystal structure determination

The synthesis and characterization of a new 24-membered tetramide macrocycle (6) related to Leigh's macrocycles and catenanes is reported. The replacement of p-xylylenediamine (Leigh) by m-xylylenediamine (this work) strongly modifies the geometry and properties of the new macrocycle. NMR spectroscopy (in DMSO?d₆ solution) and X-ray crystallography have been used to characterize compound 6. The structural features in the crystal (conformational aspects and H-bonding) have been discussed comparatively to two similar macrocycles NEWHIJ and UJUNOC.     

Synthesis of chiral threefold and sixfold functionalized macrocyclic imidazole peptides

Starting from 4-oxa- or 4-azasubstituted 2-amino-3-oxoesters and (S)-valine, chiral imidazole diamino monocarboxylic acids as well as diamino dicarboxylic acids were prepared in a few synthetic steps. Macrolactamization of the side chain protected imidazole amino acids yields the corresponding 18- and 24-membered ring analogues of the naturally occurring cyclic peptide Westiellamide with various anchoring sites. The threefold functionalized scaffolds 2b-4b and the sixfold functionalized scaffold 5 are versatile central modules for artificial receptors and ligands. Structural investigations of threefold functionalized scaffolds based on oxazole and N-methylimidazole units by DFT modeling are provided.     

Synthesis and structure of a chiral dinuclear palladium(0) complex with a 30-membered hexaolefinic macrocyclic ligand

Selective and efficient preparation of a new chiral dipalladium(0) complex with an olefinic macrocyclic ligand named (E,E,E,E,E,E)-1,6,11,16,21,26-hexakis[(4-methylphenyl)sulfonyl]-1,6,11,16,21,26-hexaazacyclotriaconta-3,8,13,18,23,28-hexaenedipalladium(0) (5) is reported. Dinuclear palladium(0) complex 5 has been fully characterized by means of NMR spectroscopy and X-ray diffraction analysis.     

Synthesis,spectral characterization and antimicrobial activity of macrocyclic Schiff-base copper(II) complexes containing polycrystalline nanosized grains

Schiff-base copper(II) complexes were prepared using macrocyclic ligands, synthesized by condensation of diethylmalonate with Schiff bases derived from o-phenylenediamine and Knoevenagel condensed β-ketoanilides (obtained by the condensation of acetoacetanilide and substituted benzaldehydes). The ligands and their copper complexes were characterized by microanalytical, mass, UV–Vis, IR, ¹H-NMR, ESR and CV studies, as well as conductivity data. Microanalytical, mass and magnetic moment analyses are consistent with formation of monomeric [CuL]Cl₂. Spectral studies indicate square-planar geometry around copper. The smaller grain sizes found from XRD data suggest that these complexes are polycrystalline with nanosized grains. The SEM images of [CuL¹]Cl₂ have leaf-like morphology. The in vitro biological screening of the investigated compounds against the bacteria Escherichia coli, Klebsiella pneumoniae, Salmonella typhi, Pseudomonas aeruginosa and Staphylococcus aureus and fungi Aspergillus niger, Rhizopus stolonifer, Aspergillus flavus, Rhizoctonia bataicola and Candida albicans were tested by the well diffusion method to assess growth inhibition. A comparative study of MIC values of the Schiff-base ligands and their complexes indicate that the complexes exhibit higher antimicrobial activity than the free ligands.     

One-pot synthesis of [1+1] and 62-membered [2+2] Schiff base macrocycles

New [1+1] and 62-membered [2+2] Schiff base macrocycles containing a 2,6-diamidopyridine subunit have been synthesized by condensation reaction of the precursors pyridine-2,6-dicarboxamide and 1,10-bis(20-formylphenyloxy)decane in the presence of phosphoric acid via a one-pot process. The cyclocondensed products were effectively isolated by gel column chromatography and characterized by ~1H NMR, FTIR, mass spectrometry and X-ray analysis. The two macrocycles have a twisted structure, and not an open ‘circular' conformation in the solid state.     

含γ-羟丙基西佛碱型大环四胺的合成研究

本文报道一种由二元伯胺高氯酸盐与3,4-二氢-吡喃-5-醛(3)一步环化缩合合成具有特殊结构的含γ-羟丙基西佛碱型大环四胺(5,6)新的简捷方法, 该法反应条件温和, 产物溶解性能好且易于处理, 产率达52～55% . 在无高氯酸存在的条件下, 脂肪族二元伯胺与3缩合只能得到半关环产物7,8 .     

乙酰丙酮缩联苯胺席夫碱的合成及晶体结构

一个多世纪以来,己有大量有关席夫碱方面的文献报道.许多Schiff碱金属配合物因具有良好的抗肿瘤、抗病毒、杀菌抑霉等多种生物活性而得到了广泛应用[1-3];其特殊的催化行为以及在酶模拟方面的功效引起了化学家的普遍重视[4,5].席夫碱中,β一二酮类化合物是一类良好的金属螯合剂,因为它能够为金属提供两个键合点,形成稳定的六元螯合环,其与稀土离子形成的配合物具有稳定的化学性质和优异的发光性能,因而具有广泛的应用前景[6].     

Synthesis, characterization and crystal structures of di-three-coordinated copper(I) macrocyclic Schiff base complexes

The air-stable di-copper(I) complexes Cu₂L(SCN)₂ (1) and Cu₂L(SCN)_1.86I_0.14 (2) of the N₄ macrocyclic Schiff base ligand L have been synthesized and characterized by IR, elemental analysis, UV-Vis and crystal structure determination. X-ray analysis of the complexes shows an approximate distorted trigonal planar geometry around each copper(I) ion that is constructed from one N-bonded thiocyanate (or iodide in 2) group and two imine nitrogen atoms. DFT calculations were used to determine the structural features of the Cu₂L(SCN)₂ complex, and these were consistent with the experimental data for the complex.     

Synthesis and structure of catena cadmium complex with 2-hydroxo-1-naphthaldehyde thiosemicarbazono tetradentate ligand

The title ligand (H₂L) and its complex [CdL(py)₂]py (L= C₁₂H₉N₃OS dianionic) have been synthesized and characterized. The complex structure determination indicates that Cd( II ) atom has a distorted octahedral coordination geometry. As an unusual tetradentate ligand, one L² chelates one Cd( II ) atom using the O, S atoms and one N atom of the hydrazino group while its another N atom links to the neighbouring Cd atom. The bridging hydrazono groups extend the compound into a catena chain. The naphthoxy rings of each neighboring unit are alternatively arranged at opposite sides of the chain, and the ring planes on the same side are parallel.     

Synthesis and characterization of three novel manganese(II) octaaza macrocyclic Schiff base complexes containing a phenanthroline and two pyridyl units as pendant arms. X-ray crystal structure determination of one manganese(II) complex

Three new branched hexadentate amines (N₆), 3,6-bis(2-pyridylmethyl)-3,6-diazaoctane-1,8-diamine (1), 3,7-bis(2-pyridylmethyl)-3,7-diazanonane-1,9-diamine (2) and 3,8-bis(2-pyridylmethyl)-3,8-diazadecane-1,10-diamine (3) have been synthesized. Subsequently, three novel Schiff base macrocyclic complexes containing a phenanthroline and two 2-pyridylmethylpendant arms have been prepared by template [1+1] cyclocondensation of 2,9-dicarboxaldehyde-1,10-phenanthroline and the branched hexadentate amines (1–3), in the presence of Mn(II) in methanol. These complexes have ligands with 18-, 19- and 20-membered hexaaza macrocycles and two 2-pyridylmethyl pendant arms (L¹, L² and L³, respectively). All the complexes have been characterized by elemental analysis and IR spectroscopy. The crystal structure of [MnL¹](ClO₄)₂ · 3CH₃CN was determined and indicates that in the solid state the complex adopts a slightly distorted hexagonal bipyramidal geometry with the Mn(II) ion located within a hexaaza macrocycle with the two 2-pyridylmethyl pendant arms coordinating in axial positions.     

Synthesis of macrocyclic heteroarylenes by consecutive inter- and intramolecular cycloadditions of thiophenylene-tethered triynes

Consecutive inter- and intramolecular [2+2+2] cycloadditions of various thiophenylene-tethered triynes were comprehensively studied by using chiral Rh catalysts. When we started from 2,3- and 3,4-thiophenylene-tethered substrates, dimerization proceeded and chiral tetraheteroarylenes were obtained. In contrast, reactions of 2,5-thiophenylene-tethered substrates gave hexaheteroarylenes as trimers. When bis- and tris(2,5-thiophenylene)-tethered triynes were used, mixtures of dimers and trimers were obtained, which included macrocyclic systems that contained up to 12 aromatic rings, and their photophysical properties were measured.     

Synthesis and structure of tetranuclear copper(Ⅱ) complex containing μ4-oxo bridge

A new dinucleating Schiff base ligand HL(L=C13H17N2O3) has been synthesised and characterized.The single crystal structure of its complex [L2Cu4O(AcO4)]·2H2O has beendetermined by X-ray diffraction methods.The result indicates that every Cu atom has its square pyramidal coordination polyhedron and there is a tetrahedral Cu4O core in the complex molecule.Its active sites where catalytic oxidation of dioxygen occurs have been inferred.     

水杨醛缩2-芴胺席夫碱的合成、晶体结构及生物活性

芴在煤焦油中的含量为1%～2%,全国每年可从中提取1.4万吨芴.芴是一种带有荧光的片状化合物,作为一种新型的发光材料主要用于制备芴基金属化合物、有机光导体、树脂、染料、Ziegler-Natta催化剂的给电子体等.