In Vitro Photodynamic Activity of 5,15-bis(3-Hydroxyphenyl)porphyrin and Its Halogenated Derivatives Against Cancer Cells

5,15-Diarylporphyrins ( 1-5 ) with hydroxyl groups and halogens as substituents were prepared by condensation between unsubstituted dipyrromethane and halogenated m -hydroxybenzaldehydes. Photophysical properties show that the nonhalogenated porphyrin 1 has higher fluorescence yield but lower singlet oxygen formation quantum yield than the halogenated derivatives due to the heavy atom effect. The in vitro activity of these derivatives was tested against WiDr colorectal adenocarcinoma and A375 melanoma cancer cells. All porphyrins present a much higher phototoxicity than Photofrin^® with IC ₅₀ values lower than the 50 n m level for WiDr cells and 25 n m level for A375 cancer cells. The most photoactive compound is the nonhalogenated porphyrin 1 which also presents the highest uptake. Halogenated derivatives present much lower uptakes than 1 . However, their photoactivity is similar to compound 1 showing that their intrinsic photoactivity (ISP) is very high. Iodinated compound 4 presents the highest ISP. The greater ability of these porphyrins to destroy cancer cells could be related to their photophysical and photochemical properties.     

TTFV molecular tweezers with phenylboronic acid and phenylboronate endgroups: modular synthesis and electrochemical responses to saccharides and fluoride ion

Tweezer-like molecular systems containing a redox-active tetrathiafulvalene vinylogue (TTFV) unit and two phenylboronate or phenylboronic acid endgroups were synthesized via the Cu-catalyzed alkyne azide coupling (i.e., click) reaction. The TTFV-phenylboronic acid derivative was found to show different differential pulse voltammetric (DPV) responses to various monosaccharides in aqueous DMSO at pH 7.41, suggesting potential use in electrochemical sensing of saccharides. Moreover, the TTFV-phenylboronate derivative exhibited strong binding to the fluoride ion, giving rise to sensitive electrochemical detection of the fluoride ion.     

Bis-thallium(I) porphyrin complexes

Treatment of octaethylporphyrin ($\text{1}$) or tetraphenylporphyrin ($\text{2}$) with more than two equiv of thallium(I) ethoxide gives the corresponding stable bis[thallium(I)] porphyrin complexes ($\text{5}$) and ($\text{6}$), respectively; these thallium(I) porphyrins are shown to have very different chemical and spectroscopic properties than do the corresponding thallium(III) porphyrin complexes.     

The cage effect on assembly of cyclic-bis-(zinc porphyrin) with 5,15-dipyridylporphyrin

An inclusion complex of cyclic bis(zinc porphyrin) 1 with 5,15-dipyridylporphyrin derivative 3 has been designed and constructed. The complex formation is induced by Zn-N coordination, and is robust (Kassoc ~ 106 L/mol) due to the presence of the cage effect of cyclic bis(zinc porphyrin). The cage-like complex as an entity is stable enough, and also convenient to achieve relative movement between the bis(zinc porphyrin) host and the dipyridylporphyrin guest connected by Zn-N coordination. The characteristic...     

Synthesis and chemical stability of (5,15-bis(2-thienyl)- and 5,15-diphenyl-3,7,13,17-tetramethyl-2,8,12,18-tetra-n-butyl-21H,23H-porphinato)copper(II)

(5,15-Bis(2-thienyl)-and 5,15-diphenyl-3,7,13,17-tetramethyl-2,8,12,18-tetra-n-butyl-21H,23H-porphinato)copper(II) complexes were synthesized and the basicity, absorption spectra (UV-Vis, IR, ¹H NMR) of the macrocyclic ligands and the stability of the complexes in AcOH-H₂SO₄ mixed solvents were studied with the aim to reveal the effect of 2-thienyl substituent on the properties of substituted porphyrins. Data on kinetics were obtained, reaction mechanism of complex dissociation was reasoned, and the effect of functional substitution on the properties of macrocyclic bases and their complexes with copper(II) were determined.     

5,15-bis(8-quinolyl)- and -bis(2-pyridyl)octaethylporphyrin. Preparation,stabilities of atropisomers,and metal-ion binding properties

5,15-Bis(8-quinolyl)octaethylporphyrin gives stable and isolable atropisomers, but the 5,15-bis(2-pyridyl) analog does not. The quinolyl group has no interaction with the central metal, but it readily binds external metal. Also described is the novel dimerization of Rh(III) complex induced by intramolecular 2-pyridyl ligands.     

Mono- and dinuclear ruthenium(II) 1,6,7,12-tetraazaperylene complexes

We report the synthesis of free 1,6,7,12-tetraazaperylene (tape). Tape was obtained from 1,1'-bis-2,7-naphthyridine by potassium promoted cyclization followed by oxidation with air. Mono- and dinuclear ruthenium(II) 1,6,7,12-tetraazaperylene complexes of the general formulas [Ru(L-L)(2)(tape)](PF(6))(2), [1](PF(6))(2)-[5](PF(6))(2), and [{Ru(L-L)(2)}(2)(μ-tape)](PF(6))(4), [6](PF(6))(4)-[10](PF(6))(4), with{L-L = phen, bpy, dmbpy (4,4'-dimethyl-2,2'-bipyridine), dtbbpy (4,4'-ditertbutyl-2,2'-bipyridine) and tmbpy (4,4'5,5'-tetramethyl-2,2'-bipyridine)}, respectively, were synthesized. The X-ray structures of tape·2CHCl(3) and the mononuclear complexes [Ru(bpy)(2)(tape)](PF(6))(2)·0.5CH(3)CN·0.5toluene, [Ru(dmbpy)(2)(tape)](PF(6))(2)·2toluene and [Ru(dtbbpy)(2)(tape)](PF(6))(2)·3acetone·0.5H(2)O were solved. The UV-vis absorption spectra and the electrochemical behavior of the ruthenium(ii) tape complexes were explored and compared with the data of the analogous dibenzoeilatin (dbneil), 2,2'-bipyrimidine (bpym) and tetrapyrido[3,2-a:2',3'-c:3',2'-h:2',3'-j]phenazin (tpphz) species.     

Mono- and dinuclear tricarbonyltechnetium(I) complexes with thiosemicarbazones

[NEt4]2[Tc(CO)3Cl3] reacts with thiosemicarbazones derived from 2,2'-dipyridyl ketone (HL3) and 4-acetylpyridine (HL4) to form stable technetium(I) complexes of the compositions [Tc(CO)3Cl(HL3-Npy,Npy)] and [Tc2(CO)6Cl2(micro-HL4-Npy,S)]. Whereas exclusively the pyridine nitrogen atoms are involved in coordination in the monomeric complex, the binuclear compound represents the first technetium complex with a coordinated thiosemicarbazone functionality.     

Efficient excitation energy transfer in long meso-meso linked Zn(II) porphyrin arrays bearing a 5,15-bisphenylethynylated Zn(II) porphyrin acceptor

Electronically coupled porphyrin arrays are suitable for artificial light harvesting antenna in light of a large absorption cross-section and fast excitation energy transfer (EET). Along this line, an artificial energy transfer model system has been synthesized, comprising of an energy donating meso-meso linked Zn(II) porphyrin array and an energy accepting 5,15-bisphenylethynylated Zn(II) porphyrin linked via a 1,4-phenylene spacer. This includes an increasing number of porphyrins in the meso-meso linked Zn(II) porphyrin array, 1, 2, 3, 6, 12, and 24 (Z1A, Z2A, Z3A, Z6A, Z12A, and Z24A). The intramolecular singlet-singlet EET processes have been examined by means of the steady-state and time-resolved spectroscopic techniques. The steady-state fluorescence comes only from the acceptor moiety in Z1A-Z12A, indicating nearly the quantitative EET. In Z24A that has a molecular length of ca. 217 A, the fluorescence comes largely from the acceptor moiety but partly from the long donor array, indicating that the intramolecular EET is not quantitative. The transient absorption spectroscopy has provided the EET rates in real time scale: (2.5 ps)(-1) for Z1A, (3.3 ps)(-1) for Z2A, (5.5 ps)(-1) for Z3A, (21 ps)(-1) for Z6A, (63 ps)(-1) for Z12A, and (108 ps)(-1) for Z24A. These results have been well explained by a revised F?rster equation (Sumi formula), which takes into account an exciton extending coherently over several porphyrin pigments in the donor array, whose length is not much shorter than the average donor-acceptor distance. Advantages of such strongly coupled porphyrin arrays in light harvesting and transmission are emphasized in terms of fast EET and a large absorption cross-section for incident light.     

Dihalodicarbonylruthenium(II)-bis(tertiaryphosphine chalcogenide) complexes

Summary Reactions of 1,1-methylene bis(diphenylphosphine oxide or sulphide) (dpmO₂ or dpmS₂) and 1-(diphenylphosphinoethyl)-2-diphenylphosphine sulphide (dpePS) with dihalodicarbonylruthenium(II) in EtOH gave 1:1 (L:M) complexes of stoichiometry: Ru(CO)₂X₂L₂ (L = dpmO₂, dpmS₂ or dpePS; X = Cl or Br), which were characterized by elemental analysis and i.r. spectroscopy. The spectra reveal that: (a) the carbonyls occupy octahedral cis-positions, and (b) dpmS₂ shows a higher coordination shift than does dpePS, probably due to the better Lewis basicity of the Ph₂P moiety as compared to the Ph₂P(S) moiety in the ligands. Cis-octahedral geometries are inferred from these studies.     

Charge transfer induced enhancement of near-IR two-photon absorption of 5,15-bis(azulenylethynyl) zinc(II) porphyrins

Intramolecular charge transfer in 5,15-bis(azulenylethynyl) substituted zinc(ii) porphyrin leads to a significant enhancement of two-photon absorption at near-IR region, which has been investigated by femtosecond Z-scan method.     

Asymmetric hydrogenation catalyzed by rhodium complexes of 2,3-bis(dimenthylphosphino)maleic anhydride and 2,3-bis(dimenthylphosphino)-N-phenylmaleimide

2,3-Bis(dimenthylphosphino)maleic anhydride and the phenylimide derivative have been prepared from 2,3-dichloromaleic anhydride and 2,3-dichloro-N-phenylmaleimide, respectively, and dimenthyl(trimethylsilyl)phosphine. These compounds have been used as ligands for Rh complexes and have been tested in the asymmetric hydrogenation of α-acetamidocinnamic acid, methyl-α-acetamidocinnamate and itaconic acid. Optical yields of up to approximately 70% were obtained with α-acetamidocinnamic acid.     

Mono- and dinuclear cyanodithioformate complexes of bis(bipyridine)ruthenium(II)

Summary A series of mono- and dinuclear cyanodithioformate complexes containing (bipy)₂Ru^II and CpRu^II moieties were prepared. The complexes were characterized using various physico-chemical techniques; spectral and electro-chemical studies of selected complexes were also made.     

Synthesis and properties of fullerene (C70) complexes of 2,6-bis(porphyrin)-substituted pyrazine derivatives bound to a Pd(II) ion

2,6-Bis(porphyrin)-substituted 3,5-dimethylpyrazine and its zinc complex bound C₇₀ to yield 1:1 inclusion complexes, which were characterised by ESI-MS, UV–vis, fluorescence and NMR spectroscopies. Association constants of the C₇₀ complexes were determined by fluorescence and NMR spectral analyses. A decrease in absorbance of the Soret band of the pyrazine derivative by the effect of C₇₀ was observed, suggesting the existence of a charge transfer interaction between C₇₀ and porphyrin. Experimentally reliable values for the association constants were obtained by the NMR method and were about six times larger than those of the corresponding C₆₀ complexes. Palladium complexation of the porphyrin–pyrazine ligand was found to enhance the association with fullerene. The association constant of 2,6-bis(porphyrin-Zn)-substituted 3,5-dimethylpyrazine-Pd(II) complex with C₇₀ was determined to be 8400 ± 900 M^? 1. From the comparison of the association constants, it was found that inclusion room for C₇₀ in the Pd(II) complex was maintained, juxtaposed between porphyrins attached to the opposite sides of the pyrazine ligands.

     

Carbon-nitrogen bond activation of amines by rhodium(III) porphyrin complexes

Carbon-nitrogen bond activation of amines by rhodium porphyrin chloride has been achieved to give rhodium porphyrin alkyl complexes. Rhodium porphyrin hydride and rhodium porphyrin dimer were proposed as the intermediates in cleaving the C-N bond.     

Synthesis and investigation of 2,8,12,18-tetrabutyl-3,7,13,17-tetramethyl-5,15-bis(2-thienyl)-21H,23H-porphin and its complexes with manganese (III) acetate and chloride

2,8,12,18-Tetrabutyl-3,7,13,17-tetramethyl-5,15-bis(2-thienyl)-21H,23H-porphin and its complexes with manganese(III) with additional acetate and chloride acido ligands were synthesized. Basing on the UV, IR, and NMR spectra and the kinetic properties of the proton transfer and the dissociation of free and coordinated porphyrin respectively it was established that in the change of porphyrin basicity at thienyl substitution the effect of the sulfur atom vacant d-orbitals involved in the conjugation was predominant. The stability of thienyl-substitued complexes of manganese(III) rises when the axial Cl^? is replaced by acetate ion.     

Study on inclusion complexes of meso-tetrakis(2-thienyl)porphyrin and Cu-meso-tetrakis(2-thienyl)porphyrin with cyclodextrins by spectroscopy method

In phosphate buffer solution of pH5.4, the interaction of meso-tetrakis(2-thienyl)porphyrin(H₂TTP) and Cu-meso-tetrakis(2-thienyl)porphyrin(Cu-TTP) with α-cyclodextrin(α-CD), β-CD, γ-CD, heptakis(2,3,6-tri-O-methyl)-β-CD(TM-β-CD) has been studied by means of UV-vis, fluorescence and ¹HNMR spectroscopy, respectively. The H₂TTP and Cu-TTP can form 1:2 inclusion complexes with TM-β-CD and 1:1 inclusion complexes with the other three cyclodextrins. In this paper, the inclusion constants (K) of H₂TTP and Cu-TTP for the formation of the inclusion complexes have been estimated from the changes of absorbance and fluorescence intensity in phosphate buffer solution. The inclusive capabilities of different kinds of cyclodextrins are compared. The result shows that the inclusion ability of α-CD with H₂TTP and Cu-TTP is the strongest among the three native CDs. The inclusion ability of modified β-CD with H₂TTP and Cu-TTP is stronger, compared to the native β-CD, which indicates that the capacity matching plays a crucial role in the inclusion procedure except for the hydrophobic effect. In addition ¹HNMR spectra supports the inclusion conformation of the TM-β-CD-Cu-TTP inclusion complex, indicating the interaction mechanism of inclusion processes.