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.
The importance of metalloporphyrins in supramolecular chemistry is examined. Applications in catalysis and in identifying molecular structures are discussed.
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.
New complexes of neptunyl(V) isothiocyanate with 4′-aryl-substituted 2,2′:6′,2″-terpyridines (Terpy) and N,N-dimethylacetamide (DMA) were obtained: (NpO2)(4′-Ph-Terpy)(DMA)(NCS)·DMA, ...(NpO2)(4′-(4-(CF3)C6H4)-Terpy)(DMA)(NCS)·2H2O·DMA, (NpO2)(4′-(3-BrC6H4)-Terpy)(DMA)(NCS)·DMA, and (NpO2)(4′-(2-(COOH)C6H4)-Terpy)(DMA)(NCS)·DMA. The structures of the compounds were determined with X-ray diffraction analysis. The neptunium coordination polyhedra were found to be pentagonal bipyramids with O atoms of the NpO2 groups in the apical positions and the equatorial planes formed by three N atoms of the terpyridine ligand, a N atom of the isothiocyanate anion, and an O atom of DMA. The influence of the substituents of the Ar group on the crystal structure is discussed. The IR spectra contain well-resolved bands of characteristic vibrations of all groups in the complex. The electronic absorption spectra are typical for neptunium(V) complexes and contain an intense narrow absorption band belonging to an f–f transition with a maximum of 988 nm and several long-wave satellites of lower intensity. The substituted terpyridines were shown to be efficient for the extraction of various valence forms of neptunium from the isothiocyanate solutions.
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 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.
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.
Studies on copper(II) tetrafluorenyl porphyrinate (CuTFP) and copper(II) tetraphenyl porphyrinate (CuTPP) have been focused on the charge carrier transport in their solid films and ...electroluminescence of their composites. In the dye layers deposited by resistive thermal evaporation, the mobilities of holes and electrons are on the order of 10–5 and 10–6 cm2 V–1 s–1 for the charge transport under the influence of traps, and the charge mobility reaches the order of 10–3 cm2 V–1 s–1 at space-charge-limited current in the nontrapping mode. For the dye molecules, the correlation between the mobility of charge carriers and the distribution of the electron density on the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), which serve as hopping sites for holes and electrons, respectively, is considered. Organic light-emitting diodes incorporating the dye molecules as emitting dopants demonstrate electroluminescence in the near-infrared (IR) range.
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