Group 12 metal complexes of [26]hexaphyrin(1.1.1.1.1.1)

Metalation of meso-hexakis(pentafluorophenyl)-substituted [26]hexaphyrin(1.1.1.1.1.1) (1) has been explored with group 12 metal ions Zn(II), Cd(II), and Hg(II). Zn(II) and Cd(II) ions afforded dinuclear gable-shaped complexes 2 and 3 in good yields, while Hg(II) ion provided bis-Hg(II) and mono-Hg(II) planar complexes (4 and 5) via C-H bond cleavage.     

Oxidation of hydroquinones with meso-hexakispentafluorophenyl [26]hexaphyrin(1.1.1.1.1.1)

Treatment of various hydroquinones and catechols with meso-pentafluorophenyl [26]hexaphyrin(1.1.1.1.1.1) provided the corresponding quinones quantitatively.     

Regioselective vicinal-dichlorination of meso-aryl [26]hexaphyrin(1.1.1.1.1.1)

Two synthetic methods are developed for halogenations of meso-hexakis(pentafluorophenyl)-substituted [26]hexaphyrin(1.1.1.1.1.1); one is regioselective trans-vicinal-dichlorination with sulfuryl chloride and the other is acid-assisted hydrohalogenation followed by oxidation with DDQ.     

Phosphonium ylides from nucleophilic addition of triphenylphosphine to [26]hexaphyrin(1.1.1.1.1.1)

[reaction: see text] Nucleophilic addition of triphenylphosphine to neutral meso-hexakis(pentafluorophenyl)-substituted [26]hexaphyrin(1.1.1.1.1.1) (1) provided a stable phosphonium ylide of [28]hexaphyrin (3), which was quantitatively oxidized to its 26pi-counterpart (4) that exhibited a planar and rectangular conformation and a diatropic ring current.     

Comparative photophysics of [26]- and [28]hexaphyrins(1.1.1.1.1.1): large two-photon absorption cross section of aromatic [26]hexaphyrins(1.1.1.1.1.1)

We have explored the electronic natures of representative expanded porphyrins, [26]- and [28]hexaphyrins, to investigate the interplay between the aromaticity and antiaromaticity that is brought by two electron oxidation/reduction processes. The excited singlet and triplet states of [26]hexaphyrin in solution exhibit lifetimes of 125 ps and 1.8 mus, respectively, as revealed by various time-resolved spectroscopic measurements. On the other hand, [28]hexaphyrin shows faster singlet and triplet lifetimes than those of [26]hexaphyrin, which is largely in accordance with the perturbation of aromaticity due to the pi electron formulation of [4n] in [28]hexaphyrins. The two-photon absorption cross-section values at 1200 nm for [26]hexaphyrins show ca. 9890 GM which is >10(2) larger than those of porphyrins. The reduced TPA values of 2600 and 810 GM of [28]hexaphyrin and perfluorinated [28]hexaphyrin, respectively, match well with their relatively short excited-state lifetimes. Overall, the enhanced excited-state lifetimes for various hexaphyrins go in line with the increased TPA cross-section values and the ring planarity.     

六元扩展卟啉的Zn2+,Cd2+,Hg2+单金属配合物的光电性质的理论研究

通过定域密度矩阵方法和含时密度泛函方法研究了六元扩展卟啉及其Zn,Cd和Hg单金属配合物的光电性质.通过计算得到扩展卟啉HP同金属Zn2+,Cd2+和Hg2+发生配位时,分子趋于平面化.配合物在Q带有弱得吸收峰,它们随着中心金属的原子序数的增加产生了红移.在B带有强吸收峰,其特征峰主要来自于中心金属离子的d轨道和同金属配位的C原子所处的吡咯环以及吡咯环两侧的meso-C原子上的苯基的参与.对于扩展卟啉极其配合物,定域密度矩阵方法也可以很好的预测光谱和电子跃迁性质.     

Conformational control of [26]hexaphyrins(1.1.1.1.1.1) by meso-thienyl substituents

Conformational preference and chemical stability of meso-aryl-substituted [26]hexaphyrins(1.1.1.1.1.1) ([26]ArH) depend upon meso-aryl substituents. Although only a planar and rectangular conformation (type-II conformation) has been identified for [26]ArH so far, we have demonstrated here that a different conformation with all the pyrroles pointing inward (type-I conformation) is preferred for [26]ArH (7 and 11-I) bearing small 2-thienyl or 3-thienyl substituents at 15- and 30-positions. Both type-I and type-II [26]ArH exhibit diatropic ring currents, reflecting aromatic character. Type-I [26]ArH, such as 7 and 11-I, have been shown to serve as an effective ligand for Pd(II) ions to provide bis-Pd(II) complexes 12 and 13 with N(3)C(1) coordination through facile C--H bond activation.     

A new entry to doubly N-confused [26]hexaphyrins(1.1.1.1.1.1) from normal [26]hexaphyrins(1.1.1.1.1.1) through an unprecedented double pyrrolic rearrangement

Treatment of hexakis(pentafluorophenyl)-substituted [26]hexaphyrin(1.1.1.1.1.1) (1) with CuCl in the presence of pyridine and molecular oxygen led to formation of doubly N-confused [26]hexaphyrin(1.1.1.1.1.1) 2 in a moderate yield through an unprecedented double pyrrolic rearrangement. Macrocycle 2 has been shown to serve as an effective bis-metal-coordinating ligand and exhibits attractive optical properties such as a sharp Soret-like band at 566 nm and low-energy fluorescence at 1058 nm.     

Highly selective Ir-catalyzed direct sixfold borylation of peripheral aromatic substituents on hexakisaryl-substituted [28]hexaphyrin(1.1.1.1.1.1)

Direct functionalization of aromatic substituents on [28]hexaphyrin was achieved by Ir-catalyzed borylation with the Smith-Miyaura-Hartwig protocol. High para selectivity was observed in the reaction on 2,6-dichlorophenyl and 2,6-dimethoxyphenyl substituents of [28]hexaphyrin. The reaction with [26]hexaphyrin resulted only in reduction of the substrate to provide [28]hexaphyrin without borylation, thus highlighting the importance of the oxidation state of substrates in this catalytic transformation. The borylated hexaphyrin can be used for Suzuki-Miyaura cross-coupling reaction.     

Regioselective nucleophilic substitution reaction of meso-hexakis(pentafluorophenyl) substituted [26]hexaphyrin

Reaction of various alkoxides led to the selective replacement of the p-fluorine substituents of meso-hexakis(pentafluorophenyl) substituted [26]hexaphyrin. Reaction with isopropyl amine gave meso-hexakis(4-isopropylamino-2,3,5,6-tetrafluorophenyl) substituted [28]hexaphyrin.     

[1.1.1.1.1]paracyclophane and [1.1.1.1.1.1]paracyclophane

The first syntheses of [1.1.1.1.1]paracyclophane ($\text{1}$) and [1.1.1.1.1.1]paracyclophane ($\text{2}$) are described, featuring a trifluoroacetic acid promoted Friedel-Crafts cycloalkylation as the final step.     

Diprotonated [28]Hexaphyrins(1.1.1.1.1.1): Triangular Antiaromatic Macrocycles

Protonation of meso‐aryl [28]hexaphyrins(1.1.1.1.1.1) triggered conformational changes. Whereas protonation with trifluoroacetic acid led to the formation of monoprotonated Möbius aromatic species, protonation with methanesulfonic acid led to the formation of diprotonated triangular antiaromatic species. A peripherally hexaphenylated [28]hexaphyrin was rationally designed and prepared to undergo diprotonation to favorably afford a triangular‐shaped antiaromatic species.     

A new reagent for the synthesis of [26]hexaphyrin: N-sulfonyl aldimine

The selective synthesis of [26]hexaphyrin(1.1.1.1.1.1) has been achieved by the reaction of meso-substituted tripyrrane and N-sulfonyl aldimine. The protocol is simple and requires only a catalytic amount of copper(II) triflate under mild reaction conditions.     

Copper(II) and oxovanadium(v) complexes of hexaphyrin(1.0.1.0.0.0)

The expanded porphyrin hexaphyrin(1.0.1.0.0.0) coordinates both early and late transition metals; a binuclear in-plane copper(ii) complex and an oxovanadium(v) derivative were prepared and characterized.     

Bismetal Complexes of 5,20‐Bis(5‐formyl‐2‐pyrrolyl)‐[26]hexaphyrin(1.1.1.1.1.1) Exhibiting Strong Near‐Infrared Region Absorptions

[26]Hexaphyrin(1.1.1.1.1.1) bearing two 5‐formyl‐2‐pyrrolyl groups at the 5‐ and 20‐positions was prepared by cross‐condensation of 5,10‐bis(pentafluorophenyl)‐substituted tripyrrane with 2,5‐diformylpyrrole as an effective binuclear metal‐coordinating ligand, owing to the two hemiporphyrin‐like NNNN pockets. In fact, metalation of this hexaphyrin with Zn^II, Cu^II, and Pd^II salts proceed smoothly at room temperature to give the corresponding bismetal complexes that displayed remarkably redshifted absorption spectra reaching deep into near infrared region. These redshifted absorption bands are ascribed, through electrochemical investigations and DFT calculations, to two structural motifs: the N‐metalopyrrole substructure that elevates the HOMO level due to the electron‐donating property and the two coordinated metal ions that serve as Lewis acids to lower the LUMO level.