Conformational landscape of meso-(1,3-dithian-2-yl)porphyrins

An investigation of the conformational landscape of 1,3-dithian-2-yl bearing porphyrins and the rotational behavior of the dithianyl substituents in meso position was carried out by variable-temperature (VT) NMR spectroscopy. Additionally, theoretical results for alternative conformations and energy barriers were obtained by molecular modeling. The study revealed different NH trans tautomers with regard to the orientation of the dithianyl ligands for the free base porphyrins 1-3. Relatively ruffled porphyrin core conformations were established for the transition states of the dithianyl rotation, resulting in a lower rotational energy barrier for the nickel(II) complex 4 compared to that of the free base systems. The data obtained and the first depiction of a rotational transition state for the rotation of bulky meso-alkyl substituents illustrate the close structural interplay between meso-alkyl substituents and the macrocycle conformation in porphyrins.     

Advances on antimicrobial photodynamic inactivation mediated by Zn(II) porphyrins

Over the years, microorganisms have developed several resistance mechanisms against standard treatments, thus limiting the effect of drugs and rendering ineffective therapies. Considering the growing number of resistant pathogens and adverse effects of conventional therapies, new antimicrobial technologies able to provide more effective, rapid, and safer treatments to inactivate pathogens, with unlikely chances of inducing resistance, are needed. In this regard, antimicrobial photodynamic inactivation (aPDI) has emerged as an alternative modality of treatment. In particular, Zn(II) porphyrins (ZnPs) hold great potential as photosensitizers (PSs) for aPDI and have been attracting increasing attention. The chemical structure of ZnPs can be tailored to produce PSs with improved chemical stability and photophysical properties, also modulating their amphiphilic and ionic characters, bioavailability, and (sub)cellular distribution. Thus, in this review, we provide a detailed report of studies published in about the last 10 years (2010–2021) focusing on aPDI mediated by ZnPs over a variety of pathogens, including bacteria, fungi, viruses, and protozoa. Fundamentals of aPDI, and porphyrin and its derivatives, especially ZnPs, are also included herein. We hope that this review can guide and be a reference for future studies related to aPDI mediated by ZnPs, and encourages more detailed studies on ZnP photophysical and photochemical properties, aiming to improve the fight against infectious diseases.     

Synthesis of 1,2,3-triazole-fused heterocycles via Pd-catalyzed cyclization of 5-iodotriazoles

A convenient approach toward polycyclic frameworks containing fused 1,2,3-triazoles is described. The synthesis consists of a Cu-catalyzed cycloaddition and an intramolecular Pd-catalyzed direct arylation or Heck reaction, and affords the products in good to excellent yields.     

Synthesis of quinolines via Rh(III)-catalyzed oxidative annulation of pyridines

Selective synthesis of quinolines has been achieved via oxidative annulation of functionalized pyridines with two alkyne molecules under Rh(III)-catalyzed cascade C-H activation of pyridines using Cu(OAc)(2) as an oxidant. The selectivity of this reaction is oxidant-dependent, particularly on the anion of the oxidant.     

Photophysical and electrochemical properties of meso-substituted thien-2-yl Zn(II) porphyrins

The influence of the thiophene ring on the ground and excited state properties of the porphyrin ring is investigated, when substituted at the meso-position. A series of mono-, di-, tri-, and tetra- meso-thien-2-yl porphyrins are studied and discussed with respect to the reference compounds zinc(II)-5,10,15,20-tetra(thien-2'-yl)porphyrin ( 1a) and zinc(II)-5,10,15,20-tetraphenylporphyrin (ZnTPP). The extended conjugated system zinc(II)-5-(5'-(5'-ethynyl-2'-thiophenecarboxaldehyde)thien-2'-yl)-10,15,20-triphenylporphyrin ( 4d) is also studied and shows enhanced charge transfer character due to the presence of the terminal aldehyde accepting group. A detailed analysis of ground and excited state UV-vis absorption, steady-state and time-resolved fluorescence, laser flash photolysis, and electrochemical data all point toward substantial electronic communication between the central Zn(II) porphyrin ring and the meso-thien-2-yl substituents, which is evident from excited state charge transfer character.     

Synthesis of 2,3-dihydroisoxazoles from propargylic N-hydroxylamines via Zn(II)-catalyzed ring-closure reaction

A novel cyclization reaction of propargylic N-hydroxylamines to 2,3, 5-trisubstituted 2,3-dihydroisoxazoles in the presence of catalytic amounts (10 mol %) of ZnI(2) and DMAP is reported. The methodology provides a mild new approach to this useful class of substituted heterocycles that complements extant methods. The unique reactivity of the propargylic N-hydroxylamine substrates in the presence of Zn(II) and DMAP may have additional applications in other, related alkyne cyclization reactions.     

Direct synthesis of 1-indanones via Pd-catalyzed olefination and ethylene glycol-promoted aldol-type annulation cascade

A wide range of multisubstituted 1-indanones of potential pharmaceutical use were synthesized in a one-pot fashion in moderate to excellent yields via palladium catalysis in ethylene glycol. The Heck reaction first installs an enol functionality on the aromatic ring; this is followed by an ethylene glycol promoted aldol-type annulation with a neighboring carbonyl group, resulting in the formation of various 1-indanones.     

A Zn(II) 5-Aminoisophthalate Coordination Polymer

The title compound, [Zn(AIP)(4,4-bipy)0.5(H2O)]n·0.75nH2O 1, was synthesized via the hydrothermal reaction of Zn(OAc)2 with 5-aminoisophthalic acid (H2AIP) and characterized by elemental analysis and infrared spectra. The complex crystallizes in monoclinic system, space group P21/c with a = 12.672(1), b = 7.6557(4), c = 16.181(1) , β = 109.187(2)o, V = 1482.6(2) 3, Z = 1, C52H52N8O23Zn4, Mr = 1418.58, Dc = 1.589 g/cm3, F(000) = 724 and μ(MoKα) = 1.685mm-1. The final R = 0.0702 and wR = 0.1524 for 1847 observed reflections with I > 2σ(I), and R = 0.0873 and wR = 0.1664 for all data. X-ray diffraction studies reveal that the title compound has an interesting 2D microporous architecture with guest water molecules inside the channel.     

Synthesis and properties of cobaltacarborane-functionalized Zn(II)-phthalocyanines

The syntheses of two new A₃B-type Zn(II)-phthalocyanines (Zn-Pcs) containing either one or two cobaltacarborane residues are reported, and the X-ray structure of a key phthalonitrile precursor is presented. The Zn-Pcs are highly soluble and exist as monomers in polar organic solvents.     

Polyformylation of copper(II) porphyrins

Vilsmeier formylation of copper(II) octaethylporphyrin (1) is shown to yield the copper(II) complexes of meso-monoformyloctaethylporphyrin, meso-α,β- and meso-α,γ-diformyloctaethylporphyrins, meso-α,β,γ-triformyloctaethylporphyrin, and meso-α,β,γ,δ-tetraformyloctaethylporphyrin. There is therefore no difference in regioselectivity of meso-diformylation between the octaethylporphyrin and etioporphyrin-I series.     

Synthesis of substituted isoquinolines via Pd-catalyzed cross-coupling approaches

Palladium complexes incorporating ligands based on a 1,3,5,7-tetramethyl-2,4,8-trioxa-6-phosphaadamantanyl scaffold were used to catalyze the arylation of ethyl cyanoacetate, malononitrile, and various ketones. The products from these reactions can be elaborated to substituted β-arylethylamines and used in microwave-assisted Pictet-Spengler reactions. The protocol developed is suitable for the synthesis of libraries of substituted isoquinolines.     

Synthesis of biaryls via decarboxylative Pd-catalyzed cross-coupling reaction

[reaction: see text] A simple and efficient route to biaryls via Pd-catalyzed decarboxylative cross-couplings of arene carboxylic acids and aryl iodides is reported. The PdCl2/AsPh3 catalytic system in the presence of Ag2CO3 in DMSO was found to be particularly efficient to perform this transformation. This reaction can be extended to the synthesis of various biaryls, including sterically hindered biaryls, with yields ranging from 58% to 90%.     

Synthesis of chromans via Pd-catalyzed alkene carboetherification reactions

A new method for the construction of 2-substituted and 2,2-disubstituted chromans via Pd-catalyzed carboetherification reactions between aryl/alkenyl halides and 2-(but-3-en-1-yl)phenols is described. These reactions effect formation of a C-O bond and a C-C bond to afford the chroman products in good yield, and also provide stereoselective access to tricyclic chroman derivatives.     

Synthesis of polysubstituted tetrahydrofurans via Pd-catalyzed carboetherification reactions

Pd-catalyzed carboetherifications of 1-, 2-, or 3-substituted γ-hydroxy internal alkenes afford tetrahydrofuran products bearing three stereocenters in good yield with moderate to good stereoselectivity.     

Synthesis and reactions of the first fluoroalkylated Ni(II) N-confused porphyrins

The first fluoroalkylated Ni(ii) N-confused porphyrins were synthesized with high regioselectivity and its further alkylation was studied.     

Synthesis and Characterization of Zn(II) and Cd(II) Complexes with Bisdithiophosphonates

2,4-Bis(4-methoxyphenyl)-1,3,2,4-dithiodiphosphetane-2,4-disulfide (Lawessons reagent) reacts with stoichiometric equivalent of alkane diols HO(CH₂)_nOH (n=2, 3, and 5) to form bisdithiophosphonic acid. The obtained crude bisdithiophosphonic acids are treated with dry NH₃ to give ammonium salts of bisdithiophosphonic acids. Ammonium salts of bisdithiophosphonic acids react with ZnSO₄ in water and Cd(Ac)₂ in ethanol to form new bisdithiophosphonate complexes of Zn(II) and Cd(II). The zinc and cadmium complexes of these tetradentate ligands are isolated in high yields. Ammonium salts of bisdithiophosphonic acids and their Zn(II) and Cd(II) complexes are characterized by elemental analyses, mass spectra (ESI), IR and NMR spectroscopies.__________From Koordinatsionnaya Khimiya, Vol. 31, No. 5, 2005, pp. 338–343.Original English Text Copyright © 2005 by Karakus, Yilmaz, Bulak.This text was submitted by the authors in English.     

Synthesis of alkynylated photo-luminescent Zn(II) and Mg(II) Schiff base complexes

A new series of photo-luminescent Zn(II) and Mg(II) Schiff base complexes were prepared by treatment of the arylethynyl-substituted salicylaldehydes obtained from the Sonogashira reaction with the metal salt followed by addition of the different diamines. Most square-planar Zn(II) complexes exhibited good quantum efficiencies. The Mg(II) complexes displayed even higher quantum yields than the corresponding Zn-complexes. Unsymmetrical Zn(II) Schiff base complexes were also successfully prepared from organic monoimines obtained as intermediates in the formation of the Mg metal Schiff base complex. The monoimine can also be prepared from the reaction of salicylaldehydes with excess diaminoarene. Two crystal structures featuring the zinc atom are reported, one with a rare four-coordinate square planar geometry and the other with a five-coordinate square pyramidal geometry.     

meso-四(对烷氧苯基)卟啉金属配合物的合成和性能研究(II)

合成了Zn、Pb两个系列卟啉金属配合物12个,其中6个为未见文献报道的新化合物,用元素分析、IR、UV、^1HNMR、MS确证了其结构。总结了Zn、Pb与卟啉类配体配合的IR、UV、^1HNMR判据。研究了这两个系列化合物的液晶性能,发现9个化合物具有液晶性。