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Dithieno[3′2′:5,6;2′′,3′′:7,8]naphtho[2,3-c][1,2,5]thiadiazole (DTNT) was designed to control the band energies of the polymers for photovoltaic materials. Electrochemical analysis showed that DTNT acts as both an electron donor and an electron acceptor, revealing the ambipolar nature of the DTNT unit. The direct arylation polymerization of DTNT with 2,2′-bithiophene (BTh) and 3,6-bis(2-thienyl)pyrrolo[3,4-c]pyrrole-1,4-dione (DPP) afforded four polymers that differed in either the unit of copolymerization or the chosen side chains. In the PDTNT-BTh series, a shoulder absorption band was observed at a longer wavelength than the intense absorption band. The PDTNT-DPP series exhibited a narrow band gap of less than 1.4 eV and a low HOMO energy of −5.43 eV. An organic photovoltaic cell that contained a PDTNT-BTh polymer with 2-ethylhexyl groups and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as an active layer afforded the best performance among the studied compounds, with a JSC of 6.98 mA cm−3, a VOC of 0.758 V, a FF of 0.52, and a PCE of 2.76%.

We study the degree of π−π interactions in two copolymers composed of 2-octylbenzotriazole and dialkyldithienosiloles with linear hexyl (P1) and branched 2-ethylhexyl groups (P2). Although the branched ethyl group can be positioned above the π-plane of dithienosilole to bring disadvantage to stack among the polymers, the solid-state absorption spectra of the polymers reveal that P2 possesses stronger interchain interactions than P1. We also evaluate the photovoltaic properties of each polymer with [6,6]-phenyl-C71-butyric acid methyl ester. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

The reaction of Sn(DPP)(OH)2 (DPP2− = 2,3,5,7,8,10,12,13,15,17,18,20-dodecaphenylporphyrin dianion) with H2F16DPPCOOH (2,3,7,8,12,13,17,18-octakis(3,5-difluorophenyl)-5-(4-carboxyphenyl)-10,15,20-triphenylporphyrin) afforded a porphyrin triad, Sn(DPP)(H2F16DPPCOO)2 (1), in which the Sn(DPP) unit is linked with the two H2F16DPPCOO− units by strong coordination bonds. The H2F16DPPCOO− unit of Sn(DPP)(H2F16DPPCOO)2 was diprotonated by the reaction with trifluoroacetic acid (CF3COOH) to afford a robust electron acceptor−donor−acceptor porphyrin triad, Sn(DPP){(H4F16DPPCOO)(CF3COO)2}2 (2), in which the Sn(DPP) unit and the H4F16DPP2+COO− (H4F16DPPCOO+) unit act as an electron donor and an acceptor, respectively. The photodynamics of 1 was examined by femtosecond laser flash photolysis measurements in PhCN to reveal that the energy transfer occurs from the singlet excited state of the Sn(DPP) unit to the H2F16DPPCOO− unit to generate the singlet excited state of H2F16DPPCOO−. In contrast to the case of 1, the t...

The excited-state photodynamics of intrasupramolecular photoinduced electron transfer was investigated in a series of hydrogen-bonded supramolecular complexes composed of diprotonated 2,3,5,7,8,10,12,13,15,17,18,20-dodecaphenylporphyrin (H(4)DPP(2+)) and electron donors bearing a carboxylate group. The formation of supramolecular complexes was examined by spectroscopic measurements. The binding constants obtained by spectroscopic titration indicate the strong binding (10(8)-10(10) M(-2)) even in a polar and coordinating solvent, benzonitrile (PhCN). The crystal structure of the supramolecular assembly using ferrocenecarboxylate (FcCOO(-)) was determined to reveal a new structural motif involving two-point and single-point hydrogen bonding among saddle-distorted H(4)DPP(2+) dication and two FcCOO(-) anions. Femtosecond laser flash photolysis was applied to investigate the photodynamics in the hydrogen-bonded supramolecular complexes. Rate constants obtained were evaluated in light of the Marcus theory of electron transfer, allowing us to determine the reorganization energy and the electronic coupling matrix constant of photoinduced electron transfer and back electron transfer to be 0.68 eV and 43 cm(-1), respectively. The distance dependence of electron transfer was also examined by using a series of ferrocenecarboxylate derivatives connected by linear phenylene linkers, and the distance dependence of the rate constant of electron transfer (k(ET)) was determined to be k(ET) = k(0) exp(-beta r), in which beta = 0.64 A(-1).

A cyclic porphyrin dimer (Ni2−CPDPy) linked by butadiyne moieties bearing 4-pyridyl groups includes a C60 molecule inside its cavity in solution to give a 1:1 inclusion complex (C60⊂Ni2−CPDPy). The charge-transfer (CT) band is observed at 645 nm in the UV−vis absorption spectrum of the solution of C60⊂Ni2−CPDPy. In the cyclic voltammogram of C60⊂Ni2−CPDPy, a small anodic shift of the porphyrin oxidation potential and a small cathodic shift of the fullerene reduction potential compared with their original redox potentials are indicative of CT interaction from the porphyrin to C60. In the crystal structure of C60⊂Ni2−CPDPy, a porphyrin nanotube is formed by the self-assembly of Ni2−CPDPy. Ni2−CPDPy molecules link together through nonclassical C−H···N hydrogen bonds and π−π interactions of the pyridyl groups along the crystallographic b axis. The included C60 molecules are linearly arranged in the nanotube to afford a supramolecular peapod. The charge-carrier mobility of the single crystal of C60⊂Ni2−CPDPy w...

A series of (porphyrinato)zinc(II) compounds were synthesized with use of 5,10,15,20-tetraphenylporphyrin (H2TPP), 2,3,5,10,12,13,15,20-octaphenylporphyrin (H2OPP), and 2,3,5,7,8,10,12,13,15,17,18,20-dodecaphenylporphyrin (H2DPP). Those compounds form complexes with aniline, pyridine, and 3- and 4-aminopyridines as axial ligands. X-ray crystallography was performed on the complexes with 3-aminopyridine (3-AP) and 4-aminopyridine (4-AP) as axial ligands. 3-Aminopyridine was revealed to bind through the amino group to the Zn(OPP), exhibiting intermolecular π–π interaction between 3-AP and one of the pyrrole rings and intermolecular NH–π interactions of the coordinated amino group with two β-phenyl groups of an adjacent molecule. In solution, the aminopyridines form a single species at ambient temperature and are assumed to have pyridine coordination through the aromatic pyridine nitrogen atom. Variable-temperature NMR spectroscopy in CD2Cl2 indicates that two different species exist at lower temperatures, suggesting that amino-bound complexes of 3-AP can be formed as a metastable species in solution, which is stabilized in the crystal as a result of noncovalent interactions. The binding constants of aminopyridines to the three kinds of (porphyrinato)zinc complexes reveal enhancement of the axial ligation by virtue of the distortion of the porphyrin ring. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Supramolecular architecture named as porphyrin nanochannels (PNCs), including tetrathiafulvalene (TTF) and p-aminophenol as electron-donating guests in the inner space, was prepared with the hydrochloride salt of dodecaphenylporphyrin ([H4DPP]Cl2) by self-assembly based on intermolecular π−π interactions. The crystal structure of the TTF-included PNC (PNC−TTF) was determined by X-ray crystallography. Intermolecular π−π interaction was recognized among peripheral phenyl groups of the porphyrin, mainly in the direction of the crystallographic c axis to form a column structure. Photoinduced electron transfer from the guest molecules to [H4DPP]Cl2 occurred to give the electron-transfer state involving cation radicals of the guest molecules and one-electron reduced [H4DPP]Cl2, {[H4DPP+•]Cl2}−, via the photoexcited singlet state of [H4DPP]Cl2 in PNC. The reactions were examined by solid-state femtosecond laser flash photolysis and ESR measurements to determine the rate constants of electron transfer and electro...

A doubly protonated hydrochloride salt of a saddle-distorted dodecaphenylporphyrin (H 2 DPP), [H 4 DPPP]Cl 2 , forms a porphyrin nanochannel (PNC). X-ray crystallography was used to determine the structure of the molecule, which revealed the inclusion of guest molecules within the PNC. Electron-donating molecules, such as p-hydroquinone and p-xylene, were selectively included within the PNC in sharp contrast to electron acceptors, such as the corresponding quinones, which were not encapsulated. This result indicates that the PNC can recognize the electronic character and steric hindrance of the guest molecules during the course of inclusion. ESR measurements (photoirradiation at 2> 340 nm at room temperature) of the PNC that contains p-hydroquinone, catechol, and tetrafluorohydroquinone guest molecules gave well-resolved signals, which were assigned to cation radicals formed without deprotonation based on results from computer simulations of the ESR spectra and density functional theory (DFT) calculations. The radicals are derived from photoinduced electron transfer from the guest molecules to the singlet state of H 4 DPP 2+ . Transient absorption spectroscopy by femtosecond laser flash photolysis allowed us to observe the formation of 1 (H 4 DPP 2+ )*, which is converted to H 4 DPP +. by electron transfer from the guest molecules to 1 (H 4 DPP 2+ )*, followed by fast disproportionation of H 4 DPP +. , and charge recombination to give diamagnetic species and the triplet excited state 3 (H 4 DPP 2+ )*, respectively.

Dithieno[3′2′:5,6;2″,3″:7,8]naphtho[2,3-c][1,2,5] thiadiazole (DTNT) and Indeno[2,1-c]fluorine (IF) derivatives were designed to control the band energies of the photovoltaic materials. Electrochemical analysis showed that DTNT acts as both an electron donor and an electron acceptor, revealing the ambipolar nature of the DTNT unit. The direct arylation polymerization of DTNT with 2,2′-bithiophene (BTh) and 3,6-bis(2-thienyl)pyrrolo[3,4-c]pyrrole-1,4-dione (DPP) afforded four polymers, and the PDTNT-DPP exhibited narrow band gap energy of 1.4 eV and a low HOMO energy of −5.43 eV. The IF derivatives with low HOMO and LUMO energies were designed and synthesized as an electron accepter for the PDTNT-DPP.

A series of trinuclear compounds [M2A(L)2(NO3)2] · n(sol) (M = Cu(II), Ni(II), Co(II); A = Pb(II), Ba(II), H2L = 2,6-bis(acetoacetyl)pyridine, sol = H2O or MeOH), has been systematically prepared by one-pot reaction of a M(II) nitrate salt, an A(II) nitrate salt and H2L in 2:1:2 ratio. They form a linear M(II)A(II)M(II) trinuclear core structure and show an antiferromagnetic interaction between the two terminal M(II) ions through the diamagnetic A(II) ion.

2,6-Bis[N,N-di(2-pyridylmethyl)aminomethyl]-4-methylphenol (Hbpmp) has afforded dinuclear Mn(II), Ni(II), and Zn(II) complexes with two bis(p-nitrophenyl) phosphate (BNP−) ions, [M2(bpmp)(bnp)2]ClO...

Kinetics of photoinduced electron transfer from a series of electron donors to the triplet excited states of a series of nonplanar porphyrins, hydrochloride salts of saddle-distorted dodecaphenylporphyrin ([H(4)DPP]Cl(2)), tetrakis(2,4,6-trimethylphyenyl)porphyrin ([H(4)TMP]Cl(2)), tetraphenylporphyrin ([H(4)TPP]Cl(2)), and octaphenylporphyrin ([H(4)OPP]Cl(2)), were investigated in comparison with those of a planar porphyrin, zinc [tetrakis(pentafluorophenyl)]porphyrin [Zn(F(20)TPP)(CH(3)CN)], in deaerated acetonitrile by laser flash photolysis. The resulting data were evaluated in light of the Marcus theory of electron transfer, allowing us to determine reorganization energies of electron transfer to be 1.21 eV for [H(4)TMP]Cl(2), 1.29 eV for [H(4)TPP]Cl(2), 1.45 eV for [H(4)OPP]Cl(2), 1.69 eV for [H(4)DPP]Cl(2), and 0.84 eV for [Zn(F(20)TPP)(CH(3)CN)]. The reorganization energies exhibited a linear correlation relative to the out-of-plane displacements, which represent the degree of nonplanarity. The rate of electron-transfer reduction of diprotonated porphyrins is significantly slowed down by conformational distortions of the porphyrin ring. This indicates that the reorganization energy of electron transfer is governed by structural change, giving a larger contribution of inner-sphere bond reorganization energy rather than outer-sphere solvent reorganization energy.

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