The synthesis of some substituted tetraarylporphyrins

The synthesis of six unsymmetrically substituted tetraarylporphyrins is reported. The compounds prepared are 5-(R),10,15,20-tritolylporphyrins, where R = 2-pyridyl, 3-pyridyl, 4-acet-amido, and 2,3 or 4-hydroxyphenyl. Four new tetrasubstituted tetraarylporphyrins (5,10,15,20-tetra-(R)-porphyrin) are also reported, where R = 3-pyridyl, 4-acetylphenyl, 4-hydroxyphenyl and 4-butoxyphenyl. The proton nmr spectra of these porphyrins are presented.     

Synthesis of meso-extended tetraarylporphyrins

The synthesis of five new meso-tetraarylporphyrins having pyridine, pyrimidine, or nitrile groups extending tetragonally via alkynyl linkages from the para positions is described. The radial extension is nearly double that of common porphyrins such as tetra-p-pyridylporphyrin. Practical quantities can be produced by Pd-coupling protocols when traditional methods fail. Applications of these extended porphyrins in the area of porous metal-organic frameworks are anticipated.     

Electrochemical synthesis of symmetrical difunctional disilanes as precursors for organofunctional silanes

Difunctional disilanes of the general type XR₂SiSiR₂X (1–5) (X = OMe, H; R = Me, Ph, H) have been synthesized by electrolysis of the appropriate chlorosilanes XR₂SiCl in an undivided cell with a constant current supply and in the absence of any complexing agent. Reduction potentials of the chlorosilane starting materials derived from cyclic voltammetry measurements were used to rationalize the results of preparative electrolyses. Organofunctional silanes of the general formula MeO(Me₂)SiC₆H₄Y (6a–c, 7) were subsequently obtained by the reaction of sym-dimethoxytetramethyldisilane (1) with NaOMe in the presence of p-functional aryl bromides BrC₆H₄Y (Y = OMe, NEt₂, NH₂).     

Unexpected bromination ring-opening of tetraarylporphyrins

An unexpected, mild, efficient bromination ring-opening method has been developed for convenient synthesis of various novel biladienes or brominated porphyrins by controlling the amounts of NBS used.     

Synthesis of three asymmetric N-confused tetraarylporphyrins

Two monosubstituted and one tetrasubstituted N-confused porphyrins (1-3) were prepared in ca. 3-5% yields using a [2 + 2] synthesis. The monosubstituted porphyrins have carbomethoxy (1) or nitro (2) substituents on one of the meso-phenyl groups, while the meso-phenyl groups of the third NCP (3) are substituted with nitro, bromo, and methyl groups in an AB(2)C pattern. The specific regiochemistry of the aryl rings around the macrocycle in each porphyrin was definitively determined using a combination of 1D ((1)H and (13)C) and 2D (gHMBC, gHSQC and ROESY) NMR spectroscopy. The absorption spectra of 1-3 in CH(2)Cl(2) are similar to those of N-confused tetraphenylporphyrin (NCTPP) but have Soret and Q bands that are shifted to lower energies with smaller extinction coefficients in comparison to those for NCTPP.     

Kinetics,mechanisms, and synthesis studies of difunctional aminopropyl terminated polydimethylsiloxane oligomers

The anionic ring opening equilibration polymerization of octamethylcyclotetrasiloxane (D₄) initiated with siloxanolates in the presence of 1,3-bis(3-aminopropyl)tetramethyldisiloxane (DSX) was investigated. The disiloxane serves as an effective chain transfer agent and source of aminopropyl functionality. Techniques for following the polymerization utilizing gas chromatography and high pressure liquid chromatography (HPLC) were developed and verified to be comparable with alternate methods published in the literature. In these polymerizations, it was concluded that the quaternary siloxanolate led to much more rapid polymerizations than the corresponding potassium based initiators. In all cases, the cyclic tetramer disappeared more rapidly than the disiloxane. However, this does not limit the utilization of the DSX for the synthesis of controlled molecular weight, difunctional species. Polar impurities, such as water in the disiloxane, were shown to influence the reactivity in these systems, especially at relatively low initiator concentrations. The work is continuing and many issues are being addressed, currently in a more quantitative fashion using the analytical procedures developed in the current study.     

Synthesis of difunctional organooxasilacycloalkanes

2,8-Dichloro-2,4,4,6,6,8,10,10,12,12-decamethyl-5-carbacyclohexasiloxane, 4,7-dichloro-2,2,4,7-tetramethyl-1,3-dioxa-2,4,7-trisilacyclohepatane, and 4,8-dichloro-2, 2,4,8-tetramethyl-1,3-dioxa-2,4,8-trisilacyclooctane were prepared for the first time by heterofunctional condensation of 1,1,7,7-tetrachloro-1,3,3,5,5,7-hexamethyl-4-carbatetrasiloxane with 1,3-dihydroxy-1,1,3,3-tetramethyldisiloxane, of 2,2,5,5-tetrachloro-2,5-disilahexane with dihydroxydimethylsilane, and of 2,2,6,6-tetrachloro-2,6-disilaheptane with dihydroxydimethylsilane, respectively. Hydrolysis of the resulting compounds afforded the corresponding dihydroxy derivatives, andtrans-isomers of some of these derivatives were isolated in individual form. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1436–1441, August, 2000.     

The first utilization of acidic ionic liquid for preparation of tetraarylporphyrins

A phase-separated acidic ionic liquid affords to catalyze a reaction of pyrrole with benzaldehyde in dichloromethane, forming porphyrins in a comparable yield to the Lindsey method and is reusable at least ten times without loss of catalytic activity.     

Radical polyaddition of difunctional vinyloxirane with thiols for synthesis of linear and networked polysulfides

Radical ring‐opening polyaddition of bifunctional vinyloxirane with multifunctional thiols was investigated. The polyaddition proceeded smoothly via the ring‐opening reaction of the oxirane moiety to afford the corresponding networked polymers bearing vinyl ether and sulfide moieties in the main chain. The thermal properties of the networked polymers and volume changes upon the polyaddition were investigated. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 783–788     

Synthesis of fluorinated difunctional monomers

In order to obtain fluorinated difunctional monomers for fluoropolyurethanes, we synthesized novel fluorinated aliphatic diisocyanates [OCNCH₂(CF_c2)_nCH₂NCO] from corresponding diols [HOCH₂CH₂(CF₂)_nCH₂CH₂OH]. Oxidation of the diols with chromium trioxide-sulfuric acid gave α, α, ω, ω-tetrahydroperfluoroalkylene dicarboxylic acids in high yields. Then treating the acids with phosphorus pentachloride afforded corresponding dicarboxyl chlorides, which are easily converted to dicarboxyl azides with hydrazoic acid-pyridine complex. Finally, on Curtius rearangement of the azides, the end products, α, α, ω, ω-tetrahydroperfluoroalkylene diisocyanates were obtained in 53% (n=4) and 19% (n=6) yields from the starting diols.     

Novel photocurable monomers: The synthesis of difunctional vinyl ethers with a phosphonate group and difunctional 1‐propenyl ethers with a phosphonate group and their photoinitiated cationic polymerization

Phosphorus‐containing vinyl ether monomers and 1‐propenyl ether monomers were prepared by the regioselective addition reaction of glycidyl vinyl ether (GVE) or 1‐propenyl glycidyl ether with diaryl phosphonates with quaternary onium salts as catalysts. The reaction of GVE with bis(4‐chlorophenyl) phenylphosphonate gave bis[1‐(4‐chlorophenoxy methyl)‐2‐(vinyloxy)ethyl]phenylphosphonate in a 68% yield. The structures of the resulting phosphorus‐containing vinyl ether monomers and 1‐propenyl ether monomers were confirmed by IR and ¹H NMR spectra and elemental analysis. Photoinitiated cationic polymerizations of the resulting phosphorus‐containing vinyl ether monomers and 1‐propenyl ether monomers were investigated with photoacid generators. The polymerization of vinyl ether groups and 1‐propenyl ether groups of the obtained monomers proceeded very smoothly with a sulfonium‐type cationic photoinitiator, bis[4‐(diphenylsulfonio)phenyl]sulfide‐bis(hexafluorophosphate), upon UV irradiation. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3105–3115, 2005     

Hetero‐difunctional dimers as building blocks for the synthesis of poly(amidoamine)s with hetero‐difunctional chain terminals and their derivatives

This article reports on a simple and straightforward preparation method of poly(amidoamine)s (PAAs) with hetero‐difunctional chain ends as well as of several up to now hardly obtainable PAA derivatives of biotechnological interest, such as for instance PAAs of controlled molecular weight and narrow polydispersity mono‐functionalized at one end with an acrylamide group, PAAs with star‐like molecular architecture, graft‐PAA‐protein conjugates, “tadpole‐like” PAA conjugates with hydrophobic moieties able to self assemble into nanoparticles in aqueous media. The key step was to design suitable building blocks consisting of hetero‐difunctional dimers (HDDs). In particular, the HDDs considered were the mono‐addition products of bis‐sec‐amines and bisacrylamides expected to give PAAs of proven biomedical potential and were obtained as hydrochlorides or trifluoroacetates. In this form, they could be indefinitely kept dormant at 0–5 °C in the dry state, whereas at room temperature and in aqueous media, they polymerized at pH > 7.5. The preparation of the above‐cited PAA derivatives did not necessarily involve the preliminary synthesis of hetero‐difunctional PAAs but was directly achieved by one‐pot polymerization of HDDs in the presence of the substrates of interest. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Ring-opening with one dioxygen molecule in the coupled oxidation of iron tetraarylporphyrins

A dioxygen molecule was activated on the iron complex of tetraarylporphyrins and both oxygen atoms of the O₂ molecule were added to cleave the macrocycle to yield a linear tetrapyrrole intermediate, from which two linear tetrapyrrole products, biladienone and bilindione, are formed, as revealed by isotope labeling experiments with oxygen-18.     

Synthesis and polycondensation of difunctional tetraazacyclododecanes

We have developed a method for getting the tetraazacyclododecane structure into the backbone of a macromolecular chain. Two different reaction processes were investigated: polycondensation from diacid macrocycles using activation of the acid functions by thionyl chloride and polycondensation from diester macrocycles by aminolysis with different aliphatic diamines. Cyclic and linear oligomers have been obtained by polycondensation of 1,7-di(ethylacetate)-4,10-ditosyl-1,4,7,10-tetraazacyclododecane with ethylenediamine and dodecanediamine. In both cases, we managed to get oligomers containing several macrocycle units into their backbone. Furthermore, these results highlighted the classical problem of the competition between cyclisation and macromolecular chain formation encountered during polycondensation reactions.     

Polyesterification of halogen containing difunctional compounds

The increasing interest in halogen containing polymers has led us to re-evaluate the different methods for the polycondensation of fluorinated and chlorinated monomers to form polyesters. The use of acid chlorides easily gives polymers with relatively high molecular weights (above 3000). We also describe in this work a new method of polytransesterification from the bishydroxyethyl esters of fluorinated and chlorinated diacids at temperatures below 200°C.     

Locked pi-expanded chlorins in two steps from simple tetraarylporphyrins

[reaction: see text] Upon tandem Reformatsky reaction, easily accessible porphyrinic ketones give "locked" chlorinic diester. Both ketones and diesters, as bases or palladium complexes, efficiently generate singlet dioxygen, as demonstrated by trapping with cholesterol.     

The efficient cyclopolymerization of silyl‐tethered styrenic difunctional monomers

The synthesis and characterization of innovative difunctional styrene‐based monomers and their cyclopolymerization is reported. Difunctional silyl‐based protecting groups with different steric hindrance (either methyl/phenyl or phenyl/phenyl) are used as “tethers” for two 4‐vinylbenzyl reactive moieties. We demonstrate that efficient cyclopolymerization, performed under free‐radical conditions or RAFT‐mediated, takes place for both monomers. RAFT polymerization allows excellent control of M_n and higher degree of polymerization when compared to uncontrolled radical polymerization, yet not optimal control of dispersities. The silyl tethering group could be removed to afford poly(p‐hydroxymethylstyrene). Thermogravimetric analysis (TGA) demonstrates the thermal robustness of the new cyclopolymers, and gives an insight on the ability of the corresponding deprotected polymer to chelate metals ions. The described strategy opens possibilities to achieve sequence control through a cyclopolymerization/tether removal strategy, when having two suitable aromatic systems with opposing electronic character and reactivities in chain cyclopolymerization. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 1593–1599     

Synthesis of difunctional 1,4-dimethyl-1,4-disilacyclohexanes

Transformations of HVinSiCl₂, HVinSi(Me)Cl, HVinSi(Me)Ph, and HVinSi(Me)NEt₂ in the presence of Pt catalyst were studied. In dilute solutions, the reaction gave a mixture of structural and stereoisomers of five- and six-membered disilacyclanes, resulting from intramolecular cyclization of the initially formed linear dimer. In the case of methyl(phenyl)disilacyclane, the structural isomers were separated andtrans-1,4-dimethyl-1,4-diphenyl-1,4-disilacyclohexane was isolated. The reaction of this product with HCl in the presence of AlCl₃ followed by hydrolysis resulted in the synthesis oftrans-1,4-dichloro- andtrans-1,4-dihydroxy-1,4-dimethyl-1,4-disilacyclohexanes. The structures of the structural and stereoisomers synthesized were confirmed by¹H,¹³C, and²⁹Si NMR and IR spectroscopies and mass spectrometry. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1734–1738, September, 1999.