Progress in conducting/semiconducting and redox-active oligomers and polymers of arylamines

Recent advances in synthesis, characterization and application of the selected conducting/semiconducting and redox-active oligomers and polymers of arylamines are reviewed. A brief historical background of the selected topics is given. The overview of the preparation, structure and properties of polyaniline, substituted polyanilines, especially those obtained by the oxidative polymerization of p-substituted anilines, poly(1-aminonaphthalene) and its derivatives, carbocyclic and heterocyclic polyaryldiamines such as poly(p-phenylenediamine) and polydiaminoacridines, is presented. The mechanism of formation of polyaniline nanostructures is discussed. Recent approaches to the preparation of one-dimensional polyaniline nanostructures are concisely reviewed, with special attention paid to the template-free falling-pH method. Current and potential future applications of oligo/polyarylamines are briefly discussed. [Projekat Ministarstva nauke Republike Srbije, br. OI 172043

Struktura i stereohemija poli-(1-naftilamina) elektrohemijski sintetisanog u neutralnom acetonitrilnom rastvoru

Poly-(1-naphthylamine) films were synthesized potentiodinamically and potentiostatically from 1-naphthylamine in neutral acetonitrile medium using a platinum electrode. These polymer films were investigated by infrared spectroscopy. Contrary to earlier published results neglecting the stereochemistry of the poly-(1-naphthylamine), we predict on the basis of quantum stereochemical analysis of the possible structural subunits of the polymer, that the ordinary N–C(4) coupled product is not predominant in the polymer because it is far removed from the expected planarity. Based on the results of IR investigations and semiempirical quantum chemical calculations, it is proposed that the polymer products are formed via mixed N–C(4), N–C(5) and N–C(7) coupling routes. The heats of formation of the oxidized 1-naphthylamine dimers and hexamers were calculated.Poli-(1-naftilaminski) filmovi sintetisani su potenciostatski i potenciodinamički iz neutralnog acetonitrilnog rastvora 1-naftilamina na platinskoj elektrodi. Ovi polimerni filmovi ispitivani su IR spektroskopijom. Za razliku od ranije publikovanih rezultata koji su zanemarivali stereohemiju poli-1(-naftilamina), u ovom radu se predviđa na osnovu kvantne stereohemijske analize mogućih strukturnih jedinica polimera da uobičajeni N–C(4) kuplovani produkt nije predominantan u polimeru, jer njegova struktura nije planarna. Na osnovu rezultata IR ispitivanja i semiempirijskih kvantno-hemijskih proračuna mi pretpostavljeno je da se polimerni produkti formiraju kombinovanim N–C(4), N–C(5) i N–C(7) načinima vezivanja 1-naftilamina. U ovom radu su takođe izračunate toplote nastajanja oksidovanih dimera i heksamera 1-naftilamina

Chemical oxidative polymerization of aromatic amines by single-electron and two-electron oxidants.

Novi semi-empirijski kvantno-hemijski uvid u mehanizam oksidacije arilamina sa peroksidisulfatom (S2O8 2–) u baznim vodenim rastvorima je predstavljen u okviru ove doktorske disertacije. Kljucna uloga arilnitrenijum-katjona u slucaju primarnih i sekundarnih arilamina, kao i dikatjona i imonijum-katjona arilamina u slucaju tercijarnih arilamina, u formiranju odgovarajucih o-aminoaril-sulfata i oligoarilamina pretpostavljena je na osnovu AM1 and RM1 kvantno-hemijske studije oksidacije anilina, C-supstituisanih (2-metilanilin, 3-metilanilin, 4-metilanilin, 2,6-dimetilanilin, antranilna kiselina, 4-aminobenzoeva kiselina, sulfanilna kiselina, sulfanilamid, 4- fenilanilin, 4-bromanilin, 3-hloranilin, i 2-nitroanilin) i N-supstituisanih anilina (Nmetilanilin, difenilamin, i N,N-dimetilanilin). Rezultati semi-empirijske kvantnohemijske studije mehanizma oksidacije arilamina sa S2O8 2– ukazuju da su arilnitrenijum-katjoni i sulfatni anjoni (SO4 2–) inicijalni proizvodi dvoelektronske oksidacije primarnih i sekundarnih arilamina sa S2O8 2–, dok se dikatjoni/imonijumkatjoni arilamina i SO4 2– inicijalno formiraju dvoelektronskom oksidacijom tercijarnih arilamina sa S2O8 2–. Dvoelektronska oksidacija arilamina sa S2O8 2– predstavlja elektron-transfer reakciju koja odreuje ukupnu brzinu oksidacije arilamina sa S2O8 2–. Veoma brza reakcija arilnitrenijum-katjona (arilamin-dikatjona, imonijum-katjona) i SO4 2– u kavezu molekula rastvaraca (vode) u kojem su nastale inicijalne reaktivne cestice vodi do formiranja odgovarajucih o-aminoaril-sulfata kao glavnih rastvornih proizvoda oksidacije. Ovaj proces predstavlja reakcioni korak koji odreuje regioselektivnost oksidacije arilamina sa S2O8 2–. Mehanizam formiranja nerastvornih oligomernih/polimernih proizvoda u toku oksidacije, kao rezultat oksidativne polimerizacije arilamina sa S2O8 2–, takoe je izucavan primenom AM1 i RM1 semiempirijskih kvantno-hemijskih metoda. Rezultati teorijske analize mehanizma oksidacije arilamina sa S2O8 2– u baznim vodenim rastvorima uporeeni su sa odgovarajucim literaturnim eksperimentalnim podacima (sinteza i izolovanje proizvoda, kineticki podaci) prikupljenim iz literature koja obuhvata poslednjih 60 godina...New computational insights into the mechanism of the oxidation of arylamines with peroxydisulfate (S2O8 2–) in an alkaline aqueous solution are presented. The key role of arylnitrenium cations, in the case of primary and secondary arylamines, and arylamine dications and immonium cations, in the case of tertiary arylamines, in the formation of corresponding o-aminoaryl sulfates, as prevalent soluble products, and oligoarylamines, as prevalent insoluble products, is proposed on the basis of the AM1 and RM1 computational study of the oxidation of aniline, ring-substituted (2-methylaniline, 3- methylaniline, 4-methylaniline, 2,6-dimethylaniline, anthranilic acid, 4-aminobenzoic acid, sulfanilic acid, sulfanilamide, 4-phenylaniline, 4-bromoaniline, 3-chloroaniline, and 2-nitroaniline) and N-substituted anilines (N-methylaniline, diphenylamine, and N,N-dimethylaniline). Arylnitrenium cations and sulfate anions (SO4 2–) are generated by rate-determining two-electron oxidation of primary and secondary arylamines with S2O8 2–, while arylamine dications/immonium cations and SO4 2– are initially formed by two-electron oxidation of tertiary arylamines with S2O8 2–. The subsequent regioselectivity-determining reaction of arylnitrenium cations/arylamine dications/immonium cations and SO4 2–, within the solvent cage, is computationally found to lead to the prevalent formation of o-aminoaryl sulfates. The formation of insoluble precipitates during the oxidation as a result of the oxidative polymerization of arylamines was also computationally studied. Quantum chemical predictions of the mechanism of the oxidation of arylamines with peroxydisulfate (S2O8 2–) in an alkaline aqueous solution were correlated with literature kinetic findings. The anilinium 5-sulfosalicylate (ANISSA) was prepared and characterized by elemental analysis, FTIR, and NMR spectroscopy. It was polymerized in aqueous solution using ammonium peroxydisulfate (APS) as an oxidant. The precipitated polyaniline 5-sulfosalicylate (PANISSA) exhibits high thermal stability and conductivity 0.13 S cm–1. The mass-average molar mass and polydispersity index of PANISSA were determined by gel-permeation chromatography (GPC) to amount 22900 g mol–1 and 2.7, respectively..

Chemical oxidative polymerization of aromatic amines by single-electron and two-electron oxidants.

Novi semi-empirijski kvantno-hemijski uvid u mehanizam oksidacije arilamina sa peroksidisulfatom (S2O8 2–) u baznim vodenim rastvorima je predstavljen u okviru ove doktorske disertacije. Kljucna uloga arilnitrenijum-katjona u slucaju primarnih i sekundarnih arilamina, kao i dikatjona i imonijum-katjona arilamina u slucaju tercijarnih arilamina, u formiranju odgovarajucih o-aminoaril-sulfata i oligoarilamina pretpostavljena je na osnovu AM1 and RM1 kvantno-hemijske studije oksidacije anilina, C-supstituisanih (2-metilanilin, 3-metilanilin, 4-metilanilin, 2,6-dimetilanilin, antranilna kiselina, 4-aminobenzoeva kiselina, sulfanilna kiselina, sulfanilamid, 4- fenilanilin, 4-bromanilin, 3-hloranilin, i 2-nitroanilin) i N-supstituisanih anilina (Nmetilanilin, difenilamin, i N,N-dimetilanilin). Rezultati semi-empirijske kvantnohemijske studije mehanizma oksidacije arilamina sa S2O8 2– ukazuju da su arilnitrenijum-katjoni i sulfatni anjoni (SO4 2–) inicijalni proizvodi dvoelektronske oksidacije primarnih i sekundarnih arilamina sa S2O8 2–, dok se dikatjoni/imonijumkatjoni arilamina i SO4 2– inicijalno formiraju dvoelektronskom oksidacijom tercijarnih arilamina sa S2O8 2–. Dvoelektronska oksidacija arilamina sa S2O8 2– predstavlja elektron-transfer reakciju koja odreuje ukupnu brzinu oksidacije arilamina sa S2O8 2–. Veoma brza reakcija arilnitrenijum-katjona (arilamin-dikatjona, imonijum-katjona) i SO4 2– u kavezu molekula rastvaraca (vode) u kojem su nastale inicijalne reaktivne cestice vodi do formiranja odgovarajucih o-aminoaril-sulfata kao glavnih rastvornih proizvoda oksidacije. Ovaj proces predstavlja reakcioni korak koji odreuje regioselektivnost oksidacije arilamina sa S2O8 2–. Mehanizam formiranja nerastvornih oligomernih/polimernih proizvoda u toku oksidacije, kao rezultat oksidativne polimerizacije arilamina sa S2O8 2–, takoe je izucavan primenom AM1 i RM1 semiempirijskih kvantno-hemijskih metoda. Rezultati teorijske analize mehanizma oksidacije arilamina sa S2O8 2– u baznim vodenim rastvorima uporeeni su sa odgovarajucim literaturnim eksperimentalnim podacima (sinteza i izolovanje proizvoda, kineticki podaci) prikupljenim iz literature koja obuhvata poslednjih 60 godina...New computational insights into the mechanism of the oxidation of arylamines with peroxydisulfate (S2O8 2–) in an alkaline aqueous solution are presented. The key role of arylnitrenium cations, in the case of primary and secondary arylamines, and arylamine dications and immonium cations, in the case of tertiary arylamines, in the formation of corresponding o-aminoaryl sulfates, as prevalent soluble products, and oligoarylamines, as prevalent insoluble products, is proposed on the basis of the AM1 and RM1 computational study of the oxidation of aniline, ring-substituted (2-methylaniline, 3- methylaniline, 4-methylaniline, 2,6-dimethylaniline, anthranilic acid, 4-aminobenzoic acid, sulfanilic acid, sulfanilamide, 4-phenylaniline, 4-bromoaniline, 3-chloroaniline, and 2-nitroaniline) and N-substituted anilines (N-methylaniline, diphenylamine, and N,N-dimethylaniline). Arylnitrenium cations and sulfate anions (SO4 2–) are generated by rate-determining two-electron oxidation of primary and secondary arylamines with S2O8 2–, while arylamine dications/immonium cations and SO4 2– are initially formed by two-electron oxidation of tertiary arylamines with S2O8 2–. The subsequent regioselectivity-determining reaction of arylnitrenium cations/arylamine dications/immonium cations and SO4 2–, within the solvent cage, is computationally found to lead to the prevalent formation of o-aminoaryl sulfates. The formation of insoluble precipitates during the oxidation as a result of the oxidative polymerization of arylamines was also computationally studied. Quantum chemical predictions of the mechanism of the oxidation of arylamines with peroxydisulfate (S2O8 2–) in an alkaline aqueous solution were correlated with literature kinetic findings. The anilinium 5-sulfosalicylate (ANISSA) was prepared and characterized by elemental analysis, FTIR, and NMR spectroscopy. It was polymerized in aqueous solution using ammonium peroxydisulfate (APS) as an oxidant. The precipitated polyaniline 5-sulfosalicylate (PANISSA) exhibits high thermal stability and conductivity 0.13 S cm–1. The mass-average molar mass and polydispersity index of PANISSA were determined by gel-permeation chromatography (GPC) to amount 22900 g mol–1 and 2.7, respectively..

Chemical oxidative polymerization of aromatic amines by single-electron and two-electron oxidants.

Novi semi-empirijski kvantno-hemijski uvid u mehanizam oksidacije arilamina sa peroksidisulfatom (S2O8 2–) u baznim vodenim rastvorima je predstavljen u okviru ove doktorske disertacije. Kljucna uloga arilnitrenijum-katjona u slucaju primarnih i sekundarnih arilamina, kao i dikatjona i imonijum-katjona arilamina u slucaju tercijarnih arilamina, u formiranju odgovarajucih o-aminoaril-sulfata i oligoarilamina pretpostavljena je na osnovu AM1 and RM1 kvantno-hemijske studije oksidacije anilina, C-supstituisanih (2-metilanilin, 3-metilanilin, 4-metilanilin, 2,6-dimetilanilin, antranilna kiselina, 4-aminobenzoeva kiselina, sulfanilna kiselina, sulfanilamid, 4- fenilanilin, 4-bromanilin, 3-hloranilin, i 2-nitroanilin) i N-supstituisanih anilina (Nmetilanilin, difenilamin, i N,N-dimetilanilin). Rezultati semi-empirijske kvantnohemijske studije mehanizma oksidacije arilamina sa S2O8 2– ukazuju da su arilnitrenijum-katjoni i sulfatni anjoni (SO4 2–) inicijalni proizvodi dvoelektronske oksidacije primarnih i sekundarnih arilamina sa S2O8 2–, dok se dikatjoni/imonijumkatjoni arilamina i SO4 2– inicijalno formiraju dvoelektronskom oksidacijom tercijarnih arilamina sa S2O8 2–. Dvoelektronska oksidacija arilamina sa S2O8 2– predstavlja elektron-transfer reakciju koja odreuje ukupnu brzinu oksidacije arilamina sa S2O8 2–. Veoma brza reakcija arilnitrenijum-katjona (arilamin-dikatjona, imonijum-katjona) i SO4 2– u kavezu molekula rastvaraca (vode) u kojem su nastale inicijalne reaktivne cestice vodi do formiranja odgovarajucih o-aminoaril-sulfata kao glavnih rastvornih proizvoda oksidacije. Ovaj proces predstavlja reakcioni korak koji odreuje regioselektivnost oksidacije arilamina sa S2O8 2–. Mehanizam formiranja nerastvornih oligomernih/polimernih proizvoda u toku oksidacije, kao rezultat oksidativne polimerizacije arilamina sa S2O8 2–, takoe je izucavan primenom AM1 i RM1 semiempirijskih kvantno-hemijskih metoda. Rezultati teorijske analize mehanizma oksidacije arilamina sa S2O8 2– u baznim vodenim rastvorima uporeeni su sa odgovarajucim literaturnim eksperimentalnim podacima (sinteza i izolovanje proizvoda, kineticki podaci) prikupljenim iz literature koja obuhvata poslednjih 60 godina...New computational insights into the mechanism of the oxidation of arylamines with peroxydisulfate (S2O8 2–) in an alkaline aqueous solution are presented. The key role of arylnitrenium cations, in the case of primary and secondary arylamines, and arylamine dications and immonium cations, in the case of tertiary arylamines, in the formation of corresponding o-aminoaryl sulfates, as prevalent soluble products, and oligoarylamines, as prevalent insoluble products, is proposed on the basis of the AM1 and RM1 computational study of the oxidation of aniline, ring-substituted (2-methylaniline, 3- methylaniline, 4-methylaniline, 2,6-dimethylaniline, anthranilic acid, 4-aminobenzoic acid, sulfanilic acid, sulfanilamide, 4-phenylaniline, 4-bromoaniline, 3-chloroaniline, and 2-nitroaniline) and N-substituted anilines (N-methylaniline, diphenylamine, and N,N-dimethylaniline). Arylnitrenium cations and sulfate anions (SO4 2–) are generated by rate-determining two-electron oxidation of primary and secondary arylamines with S2O8 2–, while arylamine dications/immonium cations and SO4 2– are initially formed by two-electron oxidation of tertiary arylamines with S2O8 2–. The subsequent regioselectivity-determining reaction of arylnitrenium cations/arylamine dications/immonium cations and SO4 2–, within the solvent cage, is computationally found to lead to the prevalent formation of o-aminoaryl sulfates. The formation of insoluble precipitates during the oxidation as a result of the oxidative polymerization of arylamines was also computationally studied. Quantum chemical predictions of the mechanism of the oxidation of arylamines with peroxydisulfate (S2O8 2–) in an alkaline aqueous solution were correlated with literature kinetic findings. The anilinium 5-sulfosalicylate (ANISSA) was prepared and characterized by elemental analysis, FTIR, and NMR spectroscopy. It was polymerized in aqueous solution using ammonium peroxydisulfate (APS) as an oxidant. The precipitated polyaniline 5-sulfosalicylate (PANISSA) exhibits high thermal stability and conductivity 0.13 S cm–1. The mass-average molar mass and polydispersity index of PANISSA were determined by gel-permeation chromatography (GPC) to amount 22900 g mol–1 and 2.7, respectively..

3,5-Dinitrosalicylic acid-assisted synthesis of self-assembled polyaniline nanorods

Self-assembled polyaniline nanorods were synthesized by the oxidation of aniline with ammonium peroxydisulfate in an aqueous solution in the presence of 3,5-dinitrosalicylic acid, using the template-free falling-pH method. The effects of the mole ratio of 3,5-dinitrosalicylic acid to aniline, i.e., of starting pH, monomer concentration, and reaction time on the yield of polymerization, molecular-weight distribution, molecular structure, morphology, and conductivity of the prepared polyanilines have been studied by gelpermeation chromatography. elemental analysis, FTIR and Raman spectroscopies, scanning and transmission electron microscopies, and conductivity measurements. The weight-average molecular weights and polydispersity index were in the range 36,400-54,900 and 3.7-7.6, respectively. Synthesized polyaniline nanorods have a diameter of 25-280 nm and a length of 0.2-1.31 mu m, and conductivities in the range (1.2-4.6) x 10(-2) S cm(-1). The formation mechanism of self-assembled polyaniline nanorods has been discussed

Novel microporous composites of MOF-5 and polyaniline with high specific surface area

Composites of metal organic framework MOF-5 and conjugated polymer polyaniline (PANI) were synthesized for the first time. Two procedures, which avoid humidity during the synthesis in order to preserve the structure of MOF-5, were applied. In the first one, dissolved part of nonconducting emeraldine base form of PANI (PANI-EB) in N,N΄-dimethylformamide was mixed with MOF-5 in different mass ratios. In the second one, the composites were prepared mechano-chemically, by using powdered conducting emeraldine salt form of PANI (PANI-ES) and solid MOF-5, mixed in chloroform in different mass ratios. The composites were characterized by various techniques: scanning electron microscopy (SEM), FTIR spectroscopy, nitrogen sorption and electrical conductivity measurements, XRD, and flame atomic absorption spectroscopy (FAAS). The procedure which used PANI-EB led to microporous PANI/MOF-5 composites with very high BET specific surface area, SBET (the highest value SBET of c.a. 2700 m2 g−1, even higher than SBET of starting pure MOF-5, showed the composite which contains 89 wt.% of MOF-5) and low conductivity (∼10-7 S cm−1). The second procedure which used PANI-ES gave microporous PANI/MOF-5 composites which showed moderate conductivities (the highest conductivity of 1.0 ⋅ 10−3 S cm-1 exhibited the composite which contains 25 wt.% of MOF-5) and also high SBET values, but lower than those measured for the composites with PANI-EB (the highest SBET of c.a. 850 m2 g-1 showed the composite of PANI doped with HCl which contains c.a. 77 wt.% of MOF-5). XRD measurements confirmed that predominately cubic crystalline structure of MOF-5 was present in almost all composites. © 2020 Elsevier B.V

Simultaneous oxidation of aniline and tannic acid with peroxydisulfate: Self-assembly of oxidation products from nanorods to microspheres

The oxidation of aniline with ammonium peroxydisulfate (APS) in aqueous solution of the plant-derived polyphenol, tannic acid, is reported. The effect of initial mole ratios [tannic acid]/[aniline] and [APS]/[aniline] on molecular structure, morphology, conductivity, and electroactivity of synthesized materials (PANI-TA) was investigated by UV-Vis, FTIR, Raman and EPR spectroscopies, scanning and transmission electron microscopies (SEM and TEM), conductivity measurements, and cyclic voltammetry, respectively. PANI-TA nanorods with the average diameter of 70-100 nm and conductivity of 1 x 10(-3) S cm(-1) were synthesized at [tannic acid]/[aniline] = 0.01 and [APS]/[aniline] = 1, while nonconductive, solid microspheres were obtained at [tannic acid]/[aniline] = 0.1 and [APS)[aniline] = 2. The mechanism of the early stages of simultaneous oxidation of aniline and tannic acid has been computationally studied by the RM1/COSMO method

The quest for optimal water quantity in the synthesis of metal-organic framework MOF-5

Efficient and simple room temperature synthesis of pure phase metal-organic framework MOF-5 has been developed, based on the use of anhydrous zinc acetate, Zn(OAc)2, as a precursor, instead of zinc acetate dihydrate. Crucial influence of water on a reaction pathway was revealed. In order to obtain MOF-5, different amounts of water have been added into the solutions of Zn(OAc)2 in N,N-dimethylformamide (DMF) to prepare in situ zinc acetate hydrates with 0.25, 0.5, and 1.0 mol of water. Commercially available zinc acetate dihydrate was also used as a precursor for comparison. These solutions were mixed at room temperature with the solution of 1,4-benzenedicarboxylic acid in DMF in the absence of any base. Based on XRD, FTIR, and SEM measurements, it was shown that the optimal amount of water for the synthesis of completely pure, crystalline phase MOF-5 is 0.25–0.5 mol of water per one mole of Zn. The reaction systems with 1.0 and 2.0 mol of water per one mole of Zn also led to solids with MOF-5 as the dominant phase, but they also contain small amounts of another phase, formed due to the decomposition (hydrolysis) and/or distortion of the MOF-5 framework in the presence of excess amounts of water. The product synthesized in the system without any added water contains MOF-5 phase in a very small amount, while main phase is zinc 1,4-benzenedicarboxylate and/or zinc hydrogen 1,4-benzenedicarboxylate. Regular cubic submicro/microcrystal morphology exhibited the samples synthesized using 0.5 and 0.25 mol water per one mole of Zn (pure MOF-5), while for the samples synthesized at mole ratios H2O/Zn2+ = 1.0 and 2.0 other particle shapes are also seen. By nitrogen sorption measurements it was found that the highest values of BET specific surface area (1937 m2 g−1), micropore volume (0.83 cm3 g−1), and micropore area (1590 m2 g−1) showed MOF-5 prepared at mole ratio H2O/Zn2+ = 0.5, while the highest yield of MOF-5 is obtained with the theoretical mole ratio H2O/Zn2+ = 0.25. Thermal stability of synthesized materials was investigated by TGA. © 2018 Elsevier Inc

Chemical oxidative polymerization of ethacridine

Novel electroactive paramagnetic ethacridine oligomers were synthesized by the oxidation of ethacridine lactate with ammonium peroxydisulfate in acidic aqueous solution. The oxidative coupling of ethacridine was proved by gel permeation chromatography and MALDI-TOF mass spectrometry demonstrating the presence of oligomeric chains. Theoretical study of the mechanism of oxidation of ethacridine has been based on the semi-empirical quantum chemical computations of heat of formation and ionization energy of ethacridine, protonated ethacridine, generated reactive species and reaction intermediates, taking into account influence of pH and solvation effects. It was revealed that the prevalent ethacridine dimers are N(C6)C5 coupled. The influence of oxidant to monomer mole ratio on the molecular structure and the morphology of ethacridine oligomers has been studied by elemental analysis, FTIR, Raman, EPR and UV-Visible spectroscopies, MALDI-TOF mass spectrometry and scanning electron microscopy. Besides unoxidized monomeric units as prevalent, oligoethacridines contain the iminoquinonoid and newly formed fused phenazine units. The electroactivity of ethacridine oligomers was investigated by cyclic voltammetry