Synthesis and characterization of porphyrin-ferrocene-fullerene triads

Novel porphyrin-fullerene systems linked by ferrocene and related model compounds were successfully synthesized and characterized. Conformationally flexible 1,1′-disubstituted ferrocene functioned as effective modulator of the conformation between porphyrin and fullerene, as ¹H NMR spectra indicated, the porphyrin and C₆₀ moieties in the triads showed gauche type conformation. The electrochemical and photophysical studies showed that there were considerable interactions between porphyrin and fullerene in the ground state due to intramolecular π-stacking of the these two chromophores, assisted by the ferrocence linker. Fluorescence lifetime measurements indicated there might be two different quenching processes occurring simultaneously (intersystem crossing and electron transfer).     

Synthesis of meso-fluorotetrabenzoporphyrins

Fluorination of quadruply bicyclo[2.2.2]octadiene-fused porphyrin (CP) with 1-chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate) (Selectfluor) occurred at the meso positions to give a mixture of various meso-fluorinated CPs, which were separated and then quantitatively transformed to the corresponding meso-fluorinated tetrafluorobenzoporphyrins (BPs) at 240 °C for 30 min. X-ray analysis of the mono-fluoro BPs revealed that the BP skeleton remained flat, which is crucial for retaining aggregation behavior similar to that of the parent BP, thus producing highly crystalline BP derivatives.     

Synthesis of new crosslinkable co-polymers containing a push-pull zinc porphyrin for non-linear optical applications

In this paper, the synthesis of a crosslinkable co-polymer containing new push-pull arylethynyl zinc porphyrins is described. The synthesis of porphyrin chromophores, analogous to Therien's porphyrin (J. Am. Chem. Soc.1996, 118, 1497-1503) functionalized with a methacrylic polymerizable group and a carboxylic acid crosslinking group was achieved with a new synthetic procedure leading to a higher overall yield compared to what was previously reported in the literature for similar and simpler structures. Radical copolymerization of the porphyrin chromophore with glycidyl methacrylate has then been carried out with success. This work opens a perspective on the possibility to integrate porphyrinic chromophore with high first-order molecular quadratic hyperpolarizability coefficient in opto-electronic devices.     

Synthesis,spectra, and complexing properties of polyoxyethylene-substituted 5,15-diphenylporphyrins

Porphyrins with two opposite meso-phenyl substituents of the macroring linked via o-positions by polyoxyethylene bridges of various lengths were prepared. Their spectra and complexing properties toward Zn²⁺ and 1,4-diazabicyclo[2.2.2]octane were examined. The rate constants of formation and stability constants of the corresponding complexes were determined, and the concentration ranges of their formation were evaluated.     

Convergent synthesis of meso-ferrocenyl porphyrins for TiO2 sensitization

Electron-donating ferrocenyl moieties have been incorporated into supramolecular carboxyporphyrin architectures Zn(II)-5-ferrocenyl-10,20-bistolyl-15-(4-methylbenzoate)porphyrin (trans-Fc-ZnP-CO₂Me), Zn(II)-5-ferrocenyl-10,15,20-tris(4-methylbenzoate)porphyrin [trans-Fc-ZnP-(CO₂Me)₃], and Zn(II)-5,15-bisferrocenyl-10,20-bis(4-benzoate)porphyrin [trans-Fc₂-ZnP-(CO₂Me)₂] for self-assembly on metal oxide nanoparticles. Efficient and economic synthesis has required a convergent strategy toward reduced symmetry trans-A₂B₂ and trans-AB₂C substitution patterns about the porphyrin macrocycle minimizing the production of porphyrin side products and increasing yields of the target ferrocenylporphyrins. Preliminary spectroscopic data in solution and in the solid state bound to mesoporous TiO₂ films are discussed.     

An efficient one-pot protocol for asymmetric bifunctionalization of 5,15-disubstituted porphyrins: direct access to meso activated alkenyl-substituted meso-formylporphyrins

An efficient one-pot protocol for the direct conversion of free base 5,15-disubstituted porphyrins into the corresponding meso activated alkenyl-substituted meso-formylporphyrins has been developed using a sequential S_NAr reaction with PyMe₂SiCH₂Li, conjugate addition to enones or alkenoates in the presence of TMSCl, and oxidation with DDQ.     

1,4-Phenylene-bridged meso-meso linked diporphyrin array

1,4-Phenylene-bridged zinc(II) meso-meso linked diporphyrin arrays were prepared by Ag(I)-promoted coupling reaction in a regioselective manner.     

Ferrocenylethenylsilatranes and a cymantrenylsilatrane

The syntheses, properties and crystal structures of two isomeric ferrocenylethenylsilatranes and 1-(3-methylcymantrenyl)silatrane are reported. The organometallic moieties and the silatrane show little structural influence on each other. The Si---N distances remain in the expected range of 2.13–2.22 Å, asserting the hypervalency of silicon. The electron-donating effect of the silatrane group is transmitted through the C---C double bond to ferrocene, as shown by the redox potentials. The first hyperpolarizability of the ferrocene derivatives was determined by hyper-Rayleigh scattering.     

Synthesis and characterization of intermediate sitting-atop (i-SAT) complexes of free base meso-tetraarylporphyrins and tin(IV) chloride

The reaction of meso-tetraarylporphyrins (H₂T(X)PP) with SnCl₄ affords green intermediate sitting-atop (i-SAT) complexes, [(H₂T(X)PP)SnCl₄]. UV–Vis, ¹H NMR and ¹³C NMR spectral data show that the porphyrin core of the complexes is distorted, thus two nitrogen atoms of the pyrrolenine groups on one side of the porphyrin plane act as electron donors to the tin center of SnCl₄. The intermediate sitting-atop (i-SAT) complex is formed each time during the incorporation of the metal center, where in the intermediate state the pyrrolic protons still remain on the porphyrin.     

Synthesis of meso-tetraphenyl porphyrins via condensation of dipyrromethanes with N-tosyl imines

A new synthetic route for the synthesis of 5,10,15,20-tetraphenyl porphyrins has been developed based on the reaction of 5-substituted dipyrromethanes with N-tosyl imines in the presence of a metal triflate catalyst. meso-Substituted tetraphenyl porphyrins were synthesized in a two-step process. The first step of the method is the metal triflate-catalyzed condensation of 5-substituted dipyrromethanes with N-tosyl imines to form a porphyrinogen intermediate and the second step is the oxidation of the porphyrinogen to porphyrin. The method was applied to the synthesis of trans-A₂B₂-tetraarylporphyrins and the products were obtained with only a trace amount of one scrambling product. The synthesis of two important building blocks for porphyrin synthesis, mono and di-sulfonamide alkylated 5-substituted dipyrromethanes, was achieved by the addition of 5-substituted dipyrromethane to N-tosyl imine. The application of mono and di-sulfonamide alkylated 5-substituted dipyrromethanes in ‘2+2’ porphyrin formation reactions is presented.     

Novel sitting-atop complexation between uranyl and meso-tetraarylporphyrins under mild conditions

We have investigated the effect of uranyl nitrate hexahydrate on free base meso-tetraarylporphyrins under mild conditions, at room temperature and containing a few drops of chloroform. The characterization of the products by ¹H NMR, IR and UV–Vis spectroscopy, elemental analysis and electrical conductometry demonstrated sitting-atop complex structures. The sitting-atop complexes are metalloporphyrins in which the metal ion is bonded to fewer than four nitrogen atoms in the distorted porphyrin plane. Such complexes may be considered as models for the initial steps of metallation of the macrocycles. This attempt is the first report of the preparation of sitting-atop complexes for actinides.     

Novel synthesis of meso-tetraarylporphyrins using CF3SO2Cl under aerobic oxidation

meso-Tetraarylporphyrins are synthesized from pyrrole and aryl aldehydes cleanly and efficiently in one pot at room temperature using equimolar amount of CF₃SO₂Cl in the presence of air as oxidant. By this novel method 5,10,15,20-tetraarylporphyrins can be prepared in excellent yields.     

Synthesis and spectroscopic characterization of meso-tetraarylporphyrins with fused phenanthrene rings

A series of meso-tetraaryl porphyrins with fused phenanthrene rings have been synthesized from boron trifluoride-catalyzed Lindsey condensation of phenanthro[9,10-c]pyrrole with various para-substituted arylaldehydes at low temperature. Their structures were characterized by UV-vis, ¹H NMR, and mass spectroscopies. The UV-vis spectra of these compounds showed remarkable bathochromic shift of the Soret band to the wavelength around 577 nm and Q-bands into the near-infrared region.     

两种含偶氮苯共轭桥新型生色团分子的合成及性能

通过重氮化偶合反应和羟醛缩合反应合成了以偶氮苯为共轭桥、以2,2,3-三甲基-4-氰基-5-二氰基亚甲基-2,5-二氢呋喃为电子受体, 而给体分别为二甲氨基和二乙氨基的两种有机非线性光学生色团分子MFNC和EFNC. 利用IR、1H NMR和元素分析对分子的结构进行了表征. TGA和DSC测试发现, MFNC的热稳定性略好于EFNC, 其热分解温度最高达266 ℃. 通过测定两种材料在氯仿、丙酮和DMSO中的紫外-可见光谱, 用溶致变色法计算得到两种材料在激光波长为1064 nm处的二阶非线性品质系数μgβ, 对比发现EFNC的μgβ值高于MFNC, 其值达59706×10-48 esu(1 esu=3.34×10-10C).     

Synthesis and characterization of new ferrocenyl bishydrazones

New ferrocenyl bishydrazones (2a–2d) have been efficiently obtained from 1,1′-ferrocenedicarboxaldehyde by a straightforward synthesis. The four new compounds have been fully characterized by NMR (¹H, ¹³C), high-resolution mass spectroscopy, and the molecular structure of compounds (2a–2d) has been elucidated by X-ray diffraction on single crystals.     

Synthesis and characterization of new porphyrin/4-quinolone conjugates

New porphyrin/4-quinolone conjugates were synthesized from the Suzuki-Miyaura coupling reaction of a β-borylated porphyrin with bromo-4-quinolones containing N-ethyl and N-d-ribofuranosyl substituents. The use of electrospray ionization tandem mass spectrometry showed important information about the fragmentation pathways of the new compounds. It was possible to distinguish between those compounds with the porphyrin moiety linked at the 6-position of the quinolone unit from their 7-substituted isomers. The new compounds showed to be good singlet oxygen generators.     

Synthesis and characterization of complexes imparting N-pyridyl bonded meso-pyridyl substituted dipyrromethanes

The meso-pyridyl substituted dipyrromethane ligands 5-(4-pyridyl)dipyrromethane (4-dpmane) and 5-(3-pyridyl)dipyrromethane (3-dpmane) have been employed in the synthesis of a series of complexes with the general formulations [(η⁶-arene)RuCl₂(L)] (η⁶-arene = C₆H₆, C₁₀H₁₄) and [(η⁵-C₅Me₅)MCl₂(L)] (M = Rh, Ir). The reaction products have been characterized by microanalyses and spectral studies and molecular structures of the complexes [(η⁶-C₁₀H₁₄)RuCl₂(4-dpmane)] and [(η⁵-C₅Me₅)IrCl₂(3-dpmane)] have been determined crystallographically. For comparative studies, geometrical optimization have been performed on the complex [(η⁵-C₅Me₅)IrCl₂(4-dpmane)] using exchange correlation functional B3LYP. Optimized bond length and angles are in good agreement with the structural data of the complex [(η⁵-C₅Me₅)IrCl₂(3-dpmane)]. The complexes [(η⁶-C₁₀H₁₄)RuCl₂(3-dpmane)], [(η⁵-C₅Me₅)RhCl₂(3-dpmane)] and [(η⁵-C₅Me₅)IrCl₂(3-dpmane)] have been employed as a transfer hydrogenation catalyst in the reduction of aldehydes. It was observed that the rhodium and iridium complexes mentioned above are more effective in this regard in comparison to the ruthenium complex.     

Sitting-atop complex formation of free base meso-tetraarylporphyrins with zirconium(IV) chloride

We have succeeded in the preparation and spectroscopic characterization of sitting-atop (SAT) complexes of meso-tetraarylporphyrins (H₂t(X)pp) with zirconium(IV) chloride under mild conditions and at room temperature, where two pyrrolenine nitrogens in the SAT complexes, [(H₂t(X)pp)ZrCl₄], coordinate to a zirconium atom and two protons still remain on the pyrrole nitrogens. UV–Vis and NMR (¹H and ¹³C) spectral data show that the porphyrin core of the SAT complexes is distorted and two pyrrolenine nitrogen atoms of the porphyrin act as electron donors to the zirconium atom of ZrCl₄.     

Synthesis and characterization of ferrocene-perylenetetracarboxylic diimide-fullerene triad

Novel ferrocene-perylenetetracarboxylic diimide-fullerene hybrid has been synthesized and characterized. UV/vis spectroscopic and cyclic voltammetric results indicate that ferrocene-contained hybrid show weak intramolecular charge transfer interaction in their ground states. The preliminary studies have shown that electron transfer from the ferrocene unit to the perylenetetracarboxylic diimide in dyad FcP takes place, while electron transfer from the ferrocene to the perylenetetracarboxylic diimide and electron transfer from the perylenetetracarboxylic diimide unit to the fullerene are proposal process in the case of FcPF.     

Synthesis of highly substituted meso-tetraarylporphyrins

meso-Tetraphenylporphyrin (and its derivatives), in the reaction with fuming yellow nitric acid (d=1.53), form either 5-(4-nitroaryl)-10,15,20-triarylporphyrin, 5,10-bis(4-nitroaryl)-15,20-diarylporphyrin, or 5,10,15-tris(4-nitroaryl)-20-arylporphyrin, depending on the reaction temperature (0-20 °C), amounts of the acid used, and reaction time. The above nitroporphyrins react, in the presence of a base (t-BuOK) at 0 °C, with carbanions (which bear nucleophugal groups at the carbanionic center: ⁻CH(Cl)SO₂Tol, ⁻CH(Br)SO₂Tol, and ⁻CH(Cl)SO₂NMe₂), leading to the nucleophilic substitution of hydrogen in one or more of the meso-nitroaryl rings. By this route, the preparation of the highly substituted ‘synthetic’ porphyrins (bearing up to ten O-, N-, Cl-, or C-substituents) was demonstrated.