This review presents a strategy for obtaining various functional derivatives of tetrapyrrole compounds based on transformations of unsaturated carbon-oxygen and carbon-carbon bonds of the ...substituents at the
position (
-formyl, vinyl, and ethynyl porphyrins). First, synthetic approaches to the preparation of these precursors are described. Then diverse pathways for the transformations of the multipotent synthons are discussed, revealing a variety of products of such reactions. The structures, electronic, and optical properties of the compounds obtained by the methods under consideration are analyzed. In addition, there is an overview of the applications of the products obtained. Biomedical use of the compounds is among the most important. Finally, the advantages of using the reviewed synthetic strategy to obtain dyes with targeted properties are highlighted.
A series of easy-to-prepare and modular chiral
,
-bidentate phosphoramidites were synthesized. With respect to Pd(II), these ligands showed the ability to form stable
,
-chelate allylic complexes. ...The structures of the ligands and their complexes were confirmed by 2D NMR spectroscopy and single-crystal X-ray diffraction. These chiral inducers provided up to 99%
in the Pd-catalyzed asymmetric allylic substitution of (
)-1,3-diphenylallyl acetate with C- and N-nucleophiles and up to 94%
in the Pd-mediated allylic alkylation of cinnamyl esters with β-ketoesters and 2,5-dimethylpyrrole. Furthermore, up to 92%
with quantitative conversion and chemo- and regioselectivity was achieved in the rare reaction between 2-(diethoxyphosphoryl)-1-phenylallyl acetate and aniline. The effects of the structural parameters, reaction conditions and ligand-to-metal ratio on the catalytic results are discussed. It was shown that the ligands surpass their analogues with different denticity.
Here, we investigated methods for carbene functionalization of porphyrinoids through metal catalyst-free thermal decomposition of their tosylhydrazones. For the first time, tetrapyrrolyl substituted ...carbenes were obtained
via
thermolysis of tosylhydrazones of the corresponding tetrapyrrolyl aldehydes and ketones in the presence of a base. The carbenes formed reacted thermally with substrates without a metal catalyst or light irradiation. Carbenes at the β-pyrrolic position of porphyrinoids reacted with styrene leading to cyclopropane derivatives of tetrapyrroles. Carbenes also reacted with 1,4-dioxane with their insertion into the C-H bond yielding a tetrapyrrole 1,4-dioxane conjugate. Thermolysis of tosylhydrazones of
meso
-formyl-β-octaalkylporphyrinoids led exclusively to the corresponding cyclopentane fused porphyrinoids
via
intramolecular carbene C-H insertion. A plausible reaction mechanism was discussed based on DFT calculations of the intermediates. The tetrapyrrolyl carbenes were found to be considerably more stable than other carbenes. The products of the functionalization of porphyrinoids
via
hydrazone formation and subsequent carbene reactions exhibited modified optical spectra. The method for carbene functionalization of porphyrinoids through thermal decomposition of their tosylhydrazones created a new synthetic pathway for tailoring the perimeter of tetrapyrrolic macrocycles. Moreover, this method allows the obtainment of dyes with controllable spectral optical properties. In particular, new tetrapyrrole derivatives possessing phytoporphyrin carbon skeletons which have not been accessible were obtained using a convenient straightforward procedure.
Porphyrinoid functionalization was performed through carbenes obtained
in situ
from tosylhydrazones. Annulated tetrapyrrole macrocycles were formed
via
intramolecular C-H insertion of carbenes.
A large family of P,S-bidentate diamidophosphite ligands were readily synthesized from accessible hydroxyl-thioether compounds. One type of Pd(II) cationic allylic complex with these ...diamidophosphites fulfilling a P-monodentate function, and three types, where the ligands act as P,S-bridging ligands (coordination polymer and head-to-head and head-to-tail dimers), were obtained. In addition, neutral Pd(II) halide complexes were generated in situ as common intermediates for both groups of cationic dimers. The structures of the ligands and complexes were elucidated by means of 2D-NMR and were confirmed by powder X-ray diffraction, as well as by DFT calculations. Asymmetric inducers of this type exhibited up to 94% ee in the Pd-mediated allylic substitution of (E)-1,3-diphenylallyl acetate with various C- and N-nucleophiles. Ee values of up to 80% were obtained in the Pd-catalyzed allylic alkylation of cinnamyl acetate with β-ketoesters. In addition, up to 61% ee was achieved in the asymmetric amination of 2-(diethoxyphosphoryl)-1-phenylallyl acetate with aniline. The effects of the diamidophosphite and thioether moieties on the catalytic activity and enantioselectivity were investigated.
A series of diamidophosphite ligands of various structures and denticities were synthesized from (11
S
,12
S
)-bis(hydroxymethyl)-9,10-dihydro-9,10-ethanoanthracene as a "roof shaped" 1,4-diol. On ...the basis of these ligands, we obtained three types of Pd(II) allylic complexes: a
P
,
P
-chelate, a
P,S
-bridged head-to-tail dinuclear complex, and complexes each containing a pair of
P
-monodentately coordinated
P
-,
P
,
N
- or
P
,
S
-ligands. The structures of the ligands and their complexes were determined using 2D NMR spectroscopy. Four diamidophosphites were also characterized
via
their X-ray structural data. This kind of stereoselector exhibited up to 98%
ee
in the Pd-mediated allylic substitution of (
E
)-1,3-diphenylallyl acetate with C- and N-nucleophiles. In the Pd-catalyzed allylic alkylation of cinnamyl acetate with various C-nucleophiles,
ee
values of up to 90% were obtained. In addition, up to 71%
ee
was achieved in the Pd-catalyzed asymmetric amination of 2-(diethoxyphosphoryl)-1-phenylallyl acetate with aniline, which is a pioneering example of diamidophosphite-type ligand involvement in this challenging reaction. The effects of the diamidophosphite moiety and the denticity of the ligands on the catalytic activity and enantioselectivity were investigated.
"Roof shaped" chiral diamidophosphites of various structures and denticities were obtained and tested in Pd-catalyzed asymmetric allylic substitution.
Cell analysis by optochemical sensing represents large and important niche in life and biomedical sciences. We present advanced multi-modal, multi-analyte sensing platform and dedicated materials for ...cell analysis based on the substituted phosphorescent Pt(II)- or Pd(II)-porphyrin indicator dyes bearing dual O2 and pH sensing functionality (MePor-SB). The study includes screening of the different host matrices for the sensor, synthesis and evaluation of new MePor-SB derivatives with altered protonation behaviour, development of the ratiometric version of the pH sensor, assessment of photoluminescent signal enhancement options, deposition of sensor coatings on common cell analysis substrates and their demonstration of sensor performance in Oxygen Consumption Rate (OCR) and Extracellular Acidification (ECA) measurements with relevant cell models. The main outcomes include the elaboration of the structure-function relationships for this biosensor system, development of the self-referenced tandem O2/pH and OCR/ECA sensing system which enables calibration-free operation, demonstration of the sensor operation on common plastic substrates in cell analysis, benchmarking against the existing platforms and real-life experiments with cells. This new sensing platform shows potential for wide practical use.
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•An advanced multi-modal, multi-analyte optochemical sensing platform for cell analysis is described.•It uses dedicated phosphorescent porphyrin dyes and sensor coatings with dual O2 and pH sensing functionality.•The sensors provide self-referencing, quantitative readout of O2 concentration and pH.•It allows simultaneous high-throughput analysis of oxygen consumption and extracellular acidification rates in cultured cells.
A method of direct borylation of vinyl-substituted porphyrinoids (porphyrins and chlorins) has been developed based on the copper catalyzed vinylic C-H activation. Ni(II) complexes of
- and ...β-vinylporphyrinoids have been transformed to the corresponding pinacolboronated derivatives with good yields and high (
)-stereoselectivity. The method provides an easy and direct access to the valuable synthons which were shown to act as nucleophylic partners in the Suzuki cross-coupling building tetrapyrrole derivatives with π-conjugation through the carbon-carbon double bond.
A simple one-step approach for the selective synthesis of
exo
-norbornenes with organosilicon substituents is suggested through the direct hydrosilylation of norbornadiene-2,5 with chlorine-free ...silanes. Using the example of norbornadiene-2,5 hydrosilylation with pentamethyldisiloxane and 1,1,1,3,5,5,5-heptamethyltrisiloxane, the possibility of obtaining
exo
-isomers of norbornenes with 100
exo
-/
endo
-selectivity is shown. The investigation of Pt-, Rh-, and Pd-complexes in combination with various ligands as catalysts was performed. The hydrosilylation of norbornadiene-2,5 in the presence of Pt- or Rh-catalysts was not selective and led to a mixture consisting of three isomers (
exo
-/
endo
-norbornenes and substituted nortricyclane). In the case of the Pd-salt/ligand catalytic system, the formation of an
endo
-isomer was not observed at all and only two isomers were formed (
exo
-norbornene and nortricyclane). The selectivity of
exo
-norbornene/nortricyclane formation strongly depended on the nature of the ligand in the Pd-catalyst. The best selectivity was revealed when
R
-MOP was the ligand, while the highest catalytic activity was reached with a dioxalane-containing ligand.
A simple one-step approach for the selective synthesis of
exo
-norbornenes with organosilicon substituents is suggested through the direct hydrosilylation of norbornadiene-2,5 with chlorine-free silanes.
The meso‐imino derivatives of the palladium (II) and nickel (II) complexes of coproporphyrins I and II and β‐octaethylporphyrin were obtained by the Vilsmeier formylation followed by interaction with ...amines. The metal complexes of the azomethines obtained were transformed to the corresponding complexes of cyclopentane and cyclopentane‐pyrrolidone fused porphyrin derivatives by thermolysis. The plausible mechanism of such transformations was suggested and substantiated with quantum chemical calculations. Meso‐cyano‐, meso‐hydroxy‐, and meso‐aminocarbonyl derivatives of β‐octaethylporphyrin were obtained by treatment of the corresponding meso‐imino derivatives with bases. Demetalation of the nickel complex of the meso‐ hydroxy‐β‐octaethylporphyrin led to formation of the free base derivative. The structures of new types of the porphyrin derivatives were determined via X‐ray powder diffraction analysis. The obtained types of porphyrins are promising candidates to use as photosensitizers in medicine applications due to their longer wave absorption combined with high stability.
New types of meso‐functionalization of porpyrins through formylation, Schiff base formation followed by thermal annulation or base treatment leading to cyclopentane‐condensed or meso‐cyano‐, meso‐amido‐, and meso‐hydroxy‐porphyrins.
Copper(
i
) halide and palladium(
ii
) chloride complexes with tricyclic monastrol analogs containing the oxadiazocine ring have been synthesized and studied. The structures of the complexes were ...investigated with IR, NMR and UV spectroscopy. Two complexes, Cu(L
1
)
2
Cl and Pd(L
1
)
2
Cl
2
, were structurally characterized by X-ray single-crystal and powder diffraction respectively. All the obtained coordination compounds were mononuclear. The ligands were coordinated with copper(
i
) and palladium(
ii
) only
via
the soft sulfur atoms of thiocarbamide fragments, while the harder nitrogen and oxygen atoms remained uncoordinated. The palladium center was coordinated by two Cl ions and two S atoms from two 4-thioxo1,3,5oxadiazocine ligands in a distorted square-planar geometry. Copper(
i
) formed a trigonal planar geometry. The complexes demonstrated significant antibacterial activity towards the
Escherichia coli
K12 TG 1 bacterial strain in contrast to the free ligands, which didn't show any noticeable activity.
The first copper(
i
) and palladium(
ii
) complexes containing monastrol analogs, 4-thioxo1,3,5oxadiazocine derivatives, have been synthesized. The complexes demonstrated significant antibacterial activity in contrast to free heterocyclic thiones.
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