Expanded Porphyrins: The Synthesis and Metal Binding Properties of Novel Tripyrrane-Containing Macrocycles

Abstract

Novel tripyrrane macrocycles have been prepared by the Schiff base condensation of 2,5-bis-(3-ethyl-5-formyl-4-methyl-pyrrol-2-ylmethyl)-3,4-diethylpyrrole and simple diamines. The structurally characterized macrocycle 1 forms 1:1 complexes with both Rh(I) and Zn(II) cations in which the metal is coordinated only to the imine nitrogens. In the presence of Cd(II) and oxygen, however, compound 1 is oxidized to the aromatic pentadentate ‘expanded porphyrin’ macrocycle 5, into which the metal cation is fully complexed.     

一步法合成一系列新型含嘧啶基团的共轭大环化合物

本文利用化合物3,5-二(5-溴-嘧啶基)-1-叔丁基苯(2)与3,5-二(4,4,5,5-四甲基-1,3,2,-二氧杂戊硼烷-2-基)-1-叔丁基苯(3)作为单体在Pd(PPh₃)₄ 催化下,经一步Suzuki交叉偶联反应合成得到一系列新型含嘧啶基团的共轭大环化合物1(1_8mer-1_12mer)。这些化合物的结构均通过₁H NMR和MALDI-TOF mass表征,并利用紫外,荧光光谱对其光学性能进行了初步的研究。实验表明这种一步法可以高效地制备一系列具有不同环大小的共轭大环化合物,这为进一步制备类似的共轭大环化合物提供了新的合成策略。     

Synthesis and Derivatization of Expanded [n]Radialenes (n=3, 4)

Versatile, iterative synthetic protocols to form expanded [n]radialenes have been developed (n=3 and 4), which allow for a variety of groups to be placed around the periphery of the macrocyclic framework. The successful use of the Sonogashira cross‐coupling reaction to complete the final ring closure demonstrates the ability of this reaction to tolerate significant ring strain while producing moderate to excellent product yields. The resulting radialenes show good stability under normal laboratory conditions in spite of their strained, cyclic structures. The physical and electronic characteristics of the macrocycles have been documented by UV‐visible spectroscopy, electrochemical methods, and X‐ray crystallography (four derivatives), and these studies provide insight into the properties of these compounds as a function of pendent substitution in terms of conjugation and donor/acceptor functionalization.     

A New Class of Non‐Racemic Chiral Macrocycles: A Conformational and Synthetic Study

Amino alcohols have been used to introduce non‐racemic chirality into macrocycles using a modular approach that relies on a Heck macrocyclisation reaction. A wide variety of macrocycles have been synthesised, and their structures studied using X‐ray crystallography and molecular modelling. A fragmentation reaction encountered during the use of (S)‐1,1‐dimethylvalinol revealed that carboxylic acids generate acylals under reaction conditions often used for Heck reactions.     

Azoalkanes: A Novel Class of Flame Retardants

Summary: The synthesis of azoalkanes such as azocyclohexane ( 1 ) and 4,4′‐bis(cyclohexylazocyclohexyl)methane ( 2 ) and their use as flame retardants in polymeric substrates is reported. For the first time it is demonstrated that azoalkanes alone can effectively provide flame retardancy and self‐extinguishing properties to poly(propylene) films at a very low concentration of 0.25 to 0.5 wt.‐%. All the poly(propylene) formulations passed DIN 4102‐1/B2 standards and the instant azoalkane‐containing poly(propylene) blends show no discoloration.

4,4′‐bis(cyclohexylazocyclohexyl)methane.     

Self-Assembly of Quinodimethanes through Covalent Bonds: A Novel Principle for the Synthesis of Functional Macrocycles

A multiplication of functional units was accomplished in a simple fashion by the tetramerization of a quinodimethane. This principle is demonstrated by the convergent construction of a macrocyclic molecule with 16 ferrocenes and a macrocyclic molecule with 16 dendritic units at the periphery of the molecule (see scheme). FG=functional group     

N-Substituted Corroles: A Novel Class of Chiral Ligands

Although known for almost 35 years , N-substituted corroles have only now been recognized as being chiral. Several examples of these species were prepared in a facile two-step synthesis and separated into their enantiomers by HPLC. The zinc(II ) complex of the corrole shown schematically was also synthesized.     

Efficient Construction and Structure Determination of Novel Macrocycles with Calixarene Bishydrazones

A series of large macrocyclic calixarene bishydrazones were efficiently synthesized by [2+2] condensation reactions of calix[4]arene 1,3‐disubstituted aldehydes with hydrated hydrazine. The X‐ray single crystal diffraction showed that macrocycles form a distinctive calixtube‐liking shape.     

Synthesis and Characterization of Novel Phthalocyanines with Four 16-Membered Diazadithia Macrocycles

Metal phthalocyanines (M = Cu, Ni, Co) 3-5 bearing four 16-membered diazadithia macrocycles at the peripheral positions were prepared. Detosylation with concentrated sulfuric acid afforded products containing both sulfonated groups on the aromatic rings of the macrocyclic substituents which are excellently soluble in water and donor sites for binding four Cu^II ions to give a pentanuclear complex.     

Synthesis of Novel C2—Symmetric Chiral Polyamide Macrocycles Containing Pyridyl Side—arm

Three novcl C2-symmetic macrocycles containing pyridyl units have been prepared by the cyclic condensation of chiral diamide intermediates with 2,6-pyridinedicarbonyl dichloride in highly diluted solution at room temperature.