Redox-active conducting polymers incorporating ferrocenes: 2. Preparation and characterisation of polypyrroles containing propyl- and butyl-tethered [1.1]ferrocenophane

The binuclear species [1.1]ferrocenophane (1), which contains two ferrocenes (Fc) connected by methylene bridges between their respective cyclopentadienyl ligands, is well known as an electrocatalyst for the conversion of strong acids (H⁺) to hydrogen gas (H₂). It may, however, also prospectively serve as a probe of the electronic properties of substituents attached at one of the bridging carbons. In order to study these properties, the pyrrole monomers 3-(1-[1.1]ferrocenophane-4-butyl)pyrrole (2) and 1-(3-(1-[1.1]ferrocenophane)-1-N-propyl)pyrrole (3) have been prepared using multi-step procedures. Their electroactive conducting co-polymers with pyrrole, P(Py-co-2) and P(Py-co-3) respectively, have also been prepared by electrochemical deposition. This work details the synthesis and characterisation of these monomers and their polymers. The latter have been characterised using cyclic voltammetry (CV), elemental analysis, UV-Vis spectroscopy, scanning electron microscopy (SEM) and four-point probe conductivity measurements.     

Polymerization of cysteine functionalized thiophenes

Different synthetic pathways leading to polythiophenes (PTs) containing units derived from methyl N-(tert-butoxycarbonyl)-S-3-thienyl-l-cysteinate (1) and methyl N-(tert-butoxycarbonyl)-S-(2-thien-3-ylethyl)-l-cysteinate (2) were investigated. The oxidative coupling with FeCl₃ applied to N-deprotected monomer 1 generates a chemically fleeting PT, whereas when applied to N-deprotected monomer 2 generates a mixture of oligomers. Two co-polymers bearing cysteine moieties, poly{[methyl N-(tert-butoxycarbonyl)-S-3-thienyl-l-cysteinate]-co-thiophene} (co-PT1) and poly{[methyl N-(tert-butoxycarbonyl)-S-(2-thien-3-ylethyl)-l-cysteinate]-co-thiophene} (co-PT2), were eventually synthesized through Stille coupling of 2,5-bis(trimethylstannyl)thiophene and 2,5-dibromo derivative of compound 1 and through the post-functionalization with protected cysteine of a tosylate co-polymer, poly{[2-(3-thienyl)ethyl 4-methylbenzenesulfonate]-co-thiophene} (co-PTTs). UV-vis, CD, NMR and GPC analyses evidenced that these polymers are able to form chiral self-assembling structures, due to the formation of a hydrogen bond network and to π-stacks, not only in the solid state but also in solution.     

Synthesis and properties of ornithine- and lysine-based poly(N-propargylamides). Responsiveness of the helical structure to acids

Ornithine- and lysine-based novel N-propargylamides, N-α-tert-butoxycarbonyl-N-δ-fluorenylmethoxycarbonyl-l-ornithine-N′-propargylamide (1), N-α-tert-butoxycarbonyl-N-?-fluorenylmethoxycarbonyl-l-lysine-N′-propargylamide (2), N-α-fluorenylmethoxycarbonyl-N-δ-tert-butoxycarbonyl-l-ornithine-N′-propargylamide (3), and N-α-fluorenylmethoxycarbonyl-N-?-tert-butoxycarbonyl-l-lysine-N′-propargylamide (4) were synthesized and polymerized with a rhodium catalyst. Polymers with moderate molecular weights were obtained in good yields. Poly(1)-poly(4) showed strong Cotton effects in THF, whose sign and wavelength depended on the substituents. They were satisfactorily converted into the corresponding polymers [poly(1a)-poly(4a)] with free amino groups. Poly(1a) and poly(2a) also formed a helix, while poly(3a) and poly(4a) did not. Poly(1a) and poly(2a) decreased the CD intensity by the addition of m- and o-phthalic acids.     

Synthesis of conjugated polymers with broad absorption bands and photovoltaic properties as bulk heterojuction solar cells

Two new broad absorbing alternating copolymers, poly[1-(2,6-diisopropylphenyl)-2,5-bis(2-thienyl)pyrrole-alt-4,7-bis(3-octyl-2-thienyl)benzothiadiazole] (PTPTTBT-P1) and poly[1-(p-octylphenyl)-2,5-bis(2-thienyl)pyrrole-alt-4,7-bis(3-octyl-2-thienyl)benzothiadiazole] (PTPTTBT-P2), were prepared via Suzuki polycondensation with high yields. The two polymers were found to show characteristic absorption in the visible region of the solar spectrum. Interestingly the absorption of PTPTTBT-P1 was found to cover the visible region from 350 to 650 nm with the broad and flat absorption maximum from 440 to 510 nm in film and the absorption of PTPTTBT-P2 was found to cover the visible region from 350 to 950 nm with the relatively distinct absorption maxima at 425 and 522 nm and very weak absorption maximum at 832 nm in film. The electrochemical band gaps of the polymers were calculated to be 1.88 eV and 1.87 eV, respectively, while the optical band gaps of the polymers were calculated to be 1.94 eV and 1.87 eV, respectively. The photovoltaic properties of polymers were investigated with bulk heterojunction (BHJ) solar cells fabricated in ITO/PEDOT:PSS/polymer:PC₇₀BM(1:5 wt%)/TiOx/Al configurations. The maximum power conversion efficiency (PCE) of the solar cell composed of PTPTTBT-P1:PC₇₀BM as an active layer was 1.57% with current density (J_sc) of 8.17 mA/cm², open circuit voltage (V_oc) of 0.52 V and fill factor (FF) of 36%.     

Synthesis and properties of optically active substituted polyacetylenes having carboxyl and/or amino groups

Polyacetylenes having carboxyl and/or amino groups in the side chain were synthesized by the polymerization of N-(2-propynyloxycarbonyl)-l-alanine (1) and l-alanine N-propargylamide (2) catalyzed with a rhodium cation complex. Poly(1_0.5-co-2_0.5) exhibited a larger CD signal than the homopolymers. The polymer mixtures obtained by the polymerization of 1 in the presence of poly(2), and those obtained by the polymerization of 2 in the presence of poly(1) showed specific rotations larger than calculated. The polymerization of propargylamine in the presence of poly(1) did not exhibit significant effect, while the polymer mixtures obtained by the polymerization of propiolic acid in the presence of poly(2) exhibited [α]_D of positive sign, although poly(2) alone exhibited [α]_D of negative sign.     

Metallocene-catalyzed synthesis of polyethylenes with side-chain triarylamines: Effects of catalyst structure and triarylamine functionality

The copolymerization of ethylene with 8-triarylamine (TAA) substituted 1-octene monomers (TAA = triphenylamine (M1), N,N-diphenyl-m-tolylamine (M2), N,N-diphenyl-1-naphthylamine (M3)) using various types of group 4 single-site catalytic systems (Cp₂ZrCl₂ (C1), rac-EBIZrCl₂ (C2), rac-SBIZrCl₂ (C3), i-PrCpFluZrCl₂ (C4), Me₂Si(η⁵-C₅Me₄)(η¹-N-^tBu)TiCl₂ (C5)) was investigated to prepare functionalized polyethylene with side-chain TAA groups. The metallocene/methylaluminoxane (MAO) catalytic systems (C1-C4) efficiently lead to the production of high-molecular-weight poly(ethylene-co-M1). While the C4/MAO catalytic system shows the highest comonomer response, the C5/MAO system exhibits the poor compatibility with the M1 comonomer. Copolymerization results of ethylene with M1-M3 using C4/MAO indicate that M1-M3 are well tolerated by both the cationic active species of C4 and MAO cocatalyst, giving rise to the copolymers with high levels of activity and molecular weight. Inspection of the aliphatic region of the ¹³C NMR spectra of the copolymers (P1-P3) having ca. 11 mol% of M1-M3, respectively, reveals the presence of isolated comonomer units with prevailing [EEMEE] monomer sequences in the polymer chain. UV-vis absorption and PL spectra exhibit an apparent low-energy band broadening for P1 and P2 indicative of intrachain aggregate formation. Whereas P2 and P3 undergo completely reversible one-electron oxidation process, P1 shows relatively poor oxidational stability.     

Helical conformation of the copolymers of l-proline derivatives based propargylether and chiral N-propargylamide

The novel acetylene monomers, l-proline derivatives based propargylethers PR (PA, PC, and PL) were synthesized by alkylation of Boc-hydroxyproline with propargyl bromide and acylation of achiral amine. The homopolymers of the novel acetylene monomer exist in no regulated higher order structure in solvents because of the lack of hydrogen bond and the unique ring structure in the pendant. Consequently, the copolymerization of l-proline-derived chiral propargylether PR with the l-alanine-derived N-propargylamide (LA) was formed and the chiroptical properties of the formed copolymers were examined. We conclude that (1) N-H of the amide group at 2-position in proline play an important role in the formation of helical conformation of poly(LA₈₈-co-PR₁₂); (2) improving the amount of PC of poly(LA-co-PC) changes the conformation of the copolymer in CHCl₃ and perturbs the leadership of LA; (3) the conformation of poly(LA₇₅-co-PC₂₅) remarkably changes with changing temperature and PC obtains the leadership in the competition on the conformation of poly(LA₇₅-co-PC₂₅) in CHCl₃ with the improvement of temperature.     

Optically active methacrylic copolymers with side-chain azoaromatic and 9-phenylcarbazole moieties

The synthesis and structural characterization of optically active copolymers such as poly[(S)-(+)-MCPP-co-(S)-MAP-N] and poly[(S)-(+)-MCPP-co-(S)-MAP-C] has been performed in order to obtain a multifunctional photonic material for chiroptical switches and for optical storage applications.The observed chiroptical properties suggest the presence of ordered chiral conformations at least for the chain segments of the macromolecules. Spectroscopic, thermal and chiroptical characterization of these copolymers demonstrate the occurrence of significant electronic interactions between the carbazole chromophores and the azobenzene moieties. The photoinduction of birefringence of copolymer films has been investigated in order to evaluate their behavior as a material for optical data storage. Surface-relief gratings (SRG) have also been inscribed on the material.The results are interpreted in terms of copolymer composition, cooperative behavior and conformational stiffness of the chromophoric co-units.     

Electrochemical study of stable N-alkoxyarylaminyl radicals

The electrochemical study of N-tert-butoxy-2,4-diphenyl-6-tert-butylphenylaminyl (1a), N-tert-butoxy-2,4-bis(4-chlorophenyl)-6-tert-butylphenylaminyl (1b), N-[2-(methoxycarbonyl)-2-propyl]-2,4-diphenyl-6-tert-butylphenylaminyl (2), and N-tert-butoxy-2,4,6-tris(4-chlorophenyl)phenylaminyl radicals (3) was performed by cyclic voltammetry using acetonitrile as the solvent and Bu₄NPF₆ as the supporting electrolyte. On cathodic scan (100 mV/s), all the radicals gave chemically reversible cyclic voltammograms, and the were determined to be −1.405 V (1a), −1.310 V (2a), −1.282 V (2b), and −1.195 V (3) (versus Fc⁺/Fc), respectively. On anodic scan (100 mV/s), on the other hand, 1a, 1b and 2 showed chemically reversible cyclic voltammograms, but 3 exhibited a partially reversible couple even on a scan rate of 500 mV/s, indicating that the cation species of 3 was less stable. The determined for 1a, 1b, 2 and 3 were 0.220, 0.280, 0.318 and 0.294 V (versus Fc⁺/Fc), respectively. The electrochemical data were compared with those of thioaminyl radicals, the corresponding sulfur analogues of 1-3.     

Polybinaphthyls incorporating chiral 2,2′-binaphthyl and isoquinoline moieties by Sonogashira reaction

Polymers P-1, P-2, P-3, P-4 and P-5 were synthesized by the polymerization of 5,8-bis(ethynyl)isoquinoline (M-1) with (R)-3,3′-diiodo-2,2′-bisbutoxy-1,1′-binaphthyl ((R)-M-2), (S)-3,3′-diiodo-2,2′-bisbutoxy-1,1′-binaphthyl ((S)-M-2), (R)-6,6′-dibromo-2,2′-bisbutoxy-1,1′-binaphthyl ((R)-M-3), (S)-6,6′-dibromo-2,2′-bisbutoxy-1,1′-binaphthyl ((S)-M-3), and rac-6,6′-dibromo-2,2′-bisbutoxy-1,1′-binaphthyl (M-4) under Sonogashira reaction, respectively. Both monomers and polymers were analyzed by NMR, MS, FT-IR, UV-vis spectroscopy, DSC-TGA, fluorescence spectroscopy, GPC and circular dichroism (CD) spectroscopy. CD spectra of polymers P-1 and P-2, P-3 and P-4 are almost identical except that they gave opposite signals at each wavelength. The long wavelength CD effect of P-1 and P-2 can be regarded as the more extended conjugated structure in the repeating unit and the helical backbone in the polymer chain. All five polymers have strong blue-green fluorescence due to the efficient energy migration from the extended π-electronic structure of the repeating unit of the polymers to the chiral binaphthyl core and are expected to provide understanding of structure-property relationships of the chiral conjugated polymers.     

Copolymerization of ethylene and 2-vinylnaphtalene with titanium and zirconium catalysts

Copolymerization of ethylene and 2-vinylnaphtalene (VN) has been investigated with dimethylsilylene(tetramethylcyclopentadienyl)(N-tert-butyl)titanium dichloride (1) and rac-isopropylidenebis(indenyl)zirconium dichloride (2) using methylaluminoxane as a cocatalyst. The copolymerization gave the corresponding copolymer in good yield. The catalyst 1 showed higher incorporation of VN than the catalyst 2. Thermal properties of the resulting copolymers were investigated by DSC in comparison with those of poly(ethylene-co-styrene), and poly(ethylene-co-VN) showed higher T_g than poly(ethylene-co-styrene).     

Aromatic diamine-based benzoxazines and their high performance thermosets

Four high-purity aromatic diamine-based benzoxazines (13-16), which could not easily be synthesized by traditional approaches, were successfully synthesized by a facile, widely useful three-step synthetic method using four typical aromatic diamines - 4,4′-diamino diphenyl methane (1), 4,4′-diamino diphenyl sulfone (2), 2,2-bis(4-(4-aminophenoxy)phenyl)propane (3), and bis(4-(4-aminophenoxy)phenyl)ether (4), respectively, as starting materials. The structures of the monomers (5-16) were confirmed by ¹H, ¹³C, ¹H-¹H and ¹H-¹³C NMR spectra. Their high performance thermosets, P(13-16), were obtained by thermal curing of benzoxazines (13-16), and their properties were studied and compared with polymer derived from bis(3,4-dihydro-2H-3-phenyl-1,3-benzoxazinyl)methane (F-a), a typical aromatic biphenol-based benzoxazine. Among the benzoxazines, 13 and F-a are constitutional isomers, but the T_g value and 5% decomposition temperature of P(13) are 53 and 111 °C, respectively, higher than those of P(F-a), demonstrating the power of the molecule-approach to enhance the thermal properties. Because of the large varieties of aromatic diamines, this approach can increase the molecule-design flexibility of benzoxazines.     

Synthesis and characterization of fluorene-carbazole and fluorene-phenothiazine copolymers with carbazole and oxadiazole pendants for organic light emitting diodes

We report the synthesis and characterization of new series of the fluorene based polymers with carbazole and oxadiazole pendants for the generation of the white emission out of the EL device. In the fluorene backbone, hole transporting units such as carbazole or phenothiazine were incorporated to improve the EL brightness and efficiency. The PFCzOxd-co-PCzs and PFCzOxd-co-PPTZs in EL spectra showed maximum peaks at around 430 nm and additional large peaks at around 530 and 500 nm, respectively. In case of PFCzOxd-alt-PCz and PFCzCzPCz-co-PFOxdOxdPCz, the EL spectra of the polymers showed two distinct peaks comprising the maximum at 427 nm, which corresponds to the EL spectra of the conjugated backbone, and additional broad peaks at around 540 and 530 nm, respectively. The CIE coordinates of the devices from PFCzOxd-alt-PCz and PFCzCzPCz-co-PFOxdOxdPCz were (0.28, 0.33) and (0.25, 0.32), respectively, approaching the value of the standard white of National Television System Committee (NTSC) (0.33, 0.33).     

Post-polymerization modification and organocatalysis using reactive statistical poly(ionic liquid)-based copolymers

Copoly(ionic liquid)s (coPILs) based on poly(styrene)-co-poly(4-vinylbenzylbutylimidazolium) with different anions (Cl⁻ and HCO₃⁻), denoted as PS-co-PVBnBuImCl 1 and PS-co-PVBnBuImHCO₃2, were used as reactive polymers for the purpose of post-polymerization modification and organic catalysis. While coPIL 1 could be derived into the corresponding poly(N-heterocyclic carbene)-silver transition metal complex referred to as poly(NHC–Ag) by a simple deprotonation/metallation sequence utilizing Ag₂O, coPIL 2 was found to quantitatively react with various electrophiles, including CS₂, isothiocyanate and transition metals (based on Pd and Au) upon formal loss of “H₂CO₃, affording the post-functionalized poly(NHC-CS₂), poly(NHC-isothiocyanate) and poly(NHC-Met) (Met = Au, Pd) copolymers. The catalytic activity of both coPILs 1 and 2 was also examined in cyclic carbonate formation by reaction between CO₂ and propylene oxide and in the benzoin condensation, respectively.     

Synthesis and properties of cyclopentadithiophene-based poly(silarylenesiloxane) derivatives

Poly(silarylenesiloxane) derivatives with 4,4-dimethylcyclopenta[2,1-b:3,4-b′]dithiophene moiety, bearing dimethyl- (P1), methylphenyl- (P2) and diphenyl- (P3) substituents on silyl moieties, were prepared via polycondensation of the corresponding disilanol monomers, that is, 2,6-bis(dimethylhydroxysilyl)-4,4-dimethylcyclopenta[2,1-b:3,4-b′]dithiophene (M1), 2,6-bis(methylphenylhydroxysilyl)-4,4-dimethylcyclopenta[2,1-b:3,4-b′]dithiophene (M2), and 2,6-bis(diphenylhydroxysilyl)-4,4-dimethylcyclopenta[2,1-b:3,4-b′]dithiophene (M3), respectively. P1-P3 exhibited the good solubility in common organic solvents, such as benzene, toluene, chloroform, dichloromethane, THF, and so on. The glass transition temperatures (T_gs) of P1, P2 and P3 were determined by differential scanning calorimetry to be 56, 97 and 137 °C, respectively, depending on the substituent on the silyl moieties. No melting temperatures (T_ms) of P1, P2 and P3 were observed, suggesting the obtained P1-P3 are amorphous polymers. The temperatures at 5% weight loss (T_d5s) of P1, P2 and P3 were 460, 459 and 479 °C, respectively, indicating that the larger number of phenyl group on the silyl moieties resulted in the better thermostability. Bathochromic and hyperchromic effects were observed in the absorption and fluorescence spectra by introducing silyl substituents onto 4,4-dimethylcyclopenta[2,1-b:3,4-b′]dithiophene moiety. In addition, the bathochromic shift of the maximum absorption (λ_abs) and the increase in the fluorescence quantum yield (Φ_F) were observed by the introduction of phenyl group onto the silyl moieties.     

Synthesis of hydroxyphenylglycine-derived novel poly(silylenevinylenephenyleneethynylene)s

The hydrosilylation polymerization of d-(−)-p-hydroxyphenylglycine-derived diethynyl monomers 1p and 1m with dihydrosilanes Si1 and Si2 was carried out using RhI(PPh₃)₃ as a catalyst to give optically active novel poly(silylenevinylenephenyleneethynylene)s [(E)-poly(1p-Si1), (E)-poly(1p-Si2), (E)-poly(1m-Si1), (E)-poly(1m-Si2), and (Z)-poly(1p-Si1)] with number-average molecular weights ranging from 2800 to 17,000 in 41-92% yields. Polymers having (E)- and (Z)-olefin moieties were obtained, wherein the (E)-/(Z)-ratios depended on the reaction conditions. The UV-vis absorption edge of (E)-poly(1p-Si1) was positioned at a wavelength longer than that of (Z)-poly(1p-Si1), indicating that (E)-vinylene-linkage extends the conjugation more largely than the (Z)-counterpart. This was also confirmed by fluorescence spectroscopy. Alkaline hydrolysis of ester moieties of these polymers gave the corresponding polymers having carboxy groups. The (E)-polymers showed different solubility in hydrophobic solvents before and after hydrolysis, but the non-hydrolyzed and hydrolyzed (Z)-polymers exhibited the same solubility.     

Synthesis and gas permeability of ester substituted poly(p-phenylene)s

Polymerizations of various ester substituted 2,5-dichlorobenzoates [substituent: linear alkyl groups (1a-f), branched alkyl groups (1g-l), cyclohexyl groups (1m-o), phenyl groups (1p-r), and oxyethylene units (1s-v)] were investigated with Ni-catalyzed/Zn-mediated system in 1-methyl-2-pyrrolidone (NMP) at 80 °C. Most of monomers bearing linear and branched alkyl groups successfully polymerized to give relatively high-molecular-weight polymers (M_n = 10,000-20,800). However, the molecular weight of the polymer having eicocyl groups was low because of steric hindrance of long alkyl chain. The polymerizations of cyclohexyl 2,5-dichlorobenzoate and phenyl 2,5-dichlorobenzoate produced low-molecular-weight polymers, while the polymerizations of monomers with alkyl cyclohexyl and alkyl phenyl groups proceeded to afford polymers with relatively high-molecular-weights. The polymers possessing oxyethylene units were obtained, but the molecular weights were low when the oxyethylene chains were long. The gas permeability of membranes of poly(p-phenylene)s with alkyl chains increased as increasing the length of alkyl chain. The membranes of poly(p-phenylene)s with phenyl groups and oxyethylene units exhibited high densities and relatively low gas permeability. However, the CO₂/N₂ separation factor of membrane of poly(p-phenylene) having oxyethylene units was as large as 73.6.     

A fluorene-containing water-soluble poly(p-phenyleneethynylene) derivative: Highly fluorescent and sensitive conjugated polymer with minor aggregation in aqueous solution

A novel cationic fluorene-containing water-soluble poly(p-phenyleneethynylene) (PPE) derivative, poly[(9,9-bis{6′-[(N,N-diethyl)-N-methylammonium]hexyl}-2,7-fluorenyleneethynylene)-alt-co-(2,5-bis{3′-[(N,N-diethyl)-N-methylammonium]-1′-oxapropyl}-1,4-phenylene)] tetraiodide (P1′), was synthesized through Sonogashira reaction and a post-polymerization treatment. P1′ emits bright blue fluorescence in H₂O with a high photoluminescence quantum yield (Φ_pl=26%). Studies on the optical properties and quenching experiments with in H₂O and MeOH show that P1′ presents minor aggregation and high Stern-Volmer constant (K_sv=2.4×10⁸ M⁻¹) in aqueous solution. The remarkably reduced tendency towards aggregation, relative to previously reported water-soluble PPEs, made the optical properties of P1′ almost insensitive to the disturbance from the common ions (non-quencher) in the solution.     

Redox and catalytic properties of new polypyrrole modified electrodes functionalized by [Ru(bpea)(bpy)H2O] complexes; bpea=N,N′-bis(2-pyridylmethyl)ethylamine, bpy=2,2′-bipyridine

New ruthenium(II) complexes containing one or two pyrrole-functionalized polypyridylic ligands have been prepared in order to study their electrochemical behaviour in heterogeneous phase, after anodic polymerization from CH₂Cl₂ solution on an electrode surface. Complexes containing one pyrrole unit have general formula [Ru(bpea-pyr)(bpy)(L)]²⁺ (bpea-pyr=N-[3-bis(2-pyridylmethyl)aminopropyl]pyrrole, bpy=2,2′-bipyridine, L=Cl, complex 3, or L=H₂O, complex 1), whereas compounds having two pyrrole units correspond to [Ru(bpea-pyr)(bpy-pyr)(L)]²⁺ (bpy-pyr=4-methyl-4′-pyrrolylbutyl-2,2′-bipyridine, L=Cl, complex 4, or L=H₂O, complex 2). Upon oxidative polymerization, all complexes form highly stable polypyrrolic films on a graphite disk electrode surface. An electrode modified with complex 2 polypyrrole coating film, C/poly-2, has been tested as heterogeneous catalyst for the oxidation of benzyl alcohol, showing a remarkably high efficiency and notably improving the results obtained with analogous complexes in homogeneous phase.     

An argon laser induced polymerization photoinitiated by both mono- and bichromophoric hemicyanine dye-borate salt ion pairs. The synthesis, spectroscopic, electrochemical and kinetic studies

A series of homodimeric hemicyanine dyes based on (p-dimethylaminostyryl)benzothiazolium, (p-dimethylaminostyryl)benzoxazolium, (p-dimethylaminostyryl)-2,3,3-trimethyl-3H-indolium residues were synthesized. Several photoredox pairs containing mono- and bichromophoric hemicyanine dyes, possessing benzothiazole, benzoxazole or indolinium group linked by 5 or 10 methylene groups have been evaluated as novel photoinitiators for free radical polymerization induced with the argon-ion laser visible emission. In tested photoredox pairs, hemicyanine dye acts as an electron acceptor and it is coupled with borate anion which is an electron donor. The photochemistry of the series of bichromophoric hemicyanine borates: 1,5-bis-[N,N′-(2,2′-(4-N,N-dimethylamino)styryl)benzothiazolium]pentane, 1,10-bis-[N,N′-(2,2′-(4-N,N-dimethylamino)styryl)benzothiazolium]decane (S5, S10), 1,5-bis-[N,N′-(2,2′-(4-N,N-dimethylamino)styryl)benzoxazolium]pentane, 1,10-bis-[N,N′-(2,2′-(4-N,N-dimethylamino)styryl)benzoxazolium]decane (O5, O10) and 1,5-bis-[N,N′-(2,2′-(4-N,N-dimethylamino)styryl)-3,3,3′,3′-tetramethyl-3H-indolium]pentane, 1,10-bis-[N,N′-(2,2′-(4-N,N-dimethylamino)styryl)-3,3,3′,3′-tetramethyl-3H-indolium]decane (I5, I10) was compared to the photochemistry of structurally related monochromophoric hemicyanine borates (S1, O1, I1).