A photocatalytic noble metal-free system for the generation of hydrogen has been constructed using Eosin Y (1) as a photosensitizer, complex [Co(dmgH)(2)pyCl](2+) (5, dmgH = dimethylglyoximate, py pyridine) molecular catalyst, and triethanolamine (TEOA) sacrificial reducing agent. The produces H(2) with an initial rate approximately 100 turnovers per hour upon irradiation visible light (lambda > 450 nm). Addition free dmgH(2) greatly increases durability addition 12 equiv (vs cobalt) to 900...

The photoisomerization of azobenzenes provides a general means for the photocontrol molecular structure and function. For applications in vivo, however, wavelength irradiation required trans-to-cis isomerization is critical since UV most visible wavelengths are strongly scattered by cells tissues. We report here that azobenzene compounds which all four positions ortho to azo group substituted with bulky electron-rich substituents can be effectively isomerized red light (630–660 nm), range...

Rhodamine photosensitizers (PSs) substituting S or Se for O in the xanthene ring give turnover numbers (TONs) as high 9000 generation of hydrogen via reduction water using [Co(III)(dmgH)(2)(py)Cl] (where dmgH = dimethylglyoximate and py pyridine) catalyst triethanolamine sacrificial electron donor. The frequencies were 0, 1700, 5500 mol H(2)/mol PS/h O, S, derivatives, respectively (Φ(H(2)) 0%, 12.2%, 32.8%, respectively), which correlates well with relative triplet yields estimated from...

We have synthesized a series of cyclopentadithiophene-benzochalcogenodiazole donor-acceptor (D-A) copolymers, wherein single atom in the benzochalcogenodiazole unit is varied from sulfur to selenium tellurium, which allows us explicitly study tellurium substitution D-A copolymers for first time. The synthesis S- and Se-containing polymers straightforward; however, Te-containing must be prepared by postpolymerization substitution. All representative dual-band optical absorption profile,...

Four mononuclear Cu(I) complexes of 2-(2'-pyridyl)benzimidazolylbenzene (pbb) with four different ancillary phosphine ligands PPh3, bis[2-(diphenylphosphino)phenyl]ether (DPEphos), bis(diphenylphosphino)ethane (dppe), and bis(diphenylphosphinomethyl)diphenylborate (DPPMB) have been synthesized. The crystal structures [Cu(pbb)(PPh3)2][BF4] (1), [Cu(pbb)(dppe)][BF4] (2), [Cu(pbb)(DPEphos)][BF4] (3), the neutral complex [Cu(pbb)(DPPMB)] (4) were determined by single-crystal X-ray diffraction...

A diboron compound with both 3-coordinate boron and 4-coordinate centers, (5-BMes2-2-ph-py)BMes2 (1) its monoboron analogue, (2-ph-py)BMes2 (2) have been synthesized. Both compounds are luminescent but a high sensitivity toward light. UV ambient light cause to isomerize 1a 2a, respectively, via the formation of C-C bond between mesityl phenyl group, accompanied by drastic color change from yellow or colorless dark olive green blue. The structures 2a were established 2D NMR experiments...

Density functional theory (DFT) calculations are useful to model orbital energies of conjugated polymers, yet discrepancy between and experiment exist. Here we evaluate a series relatively straightforward calculation methods using the standard Gaussian 09 software package. Five were performed on 22 different polymer compounds at B3LYP CAM-B3LYP levels results compared with experiment. Chain length saturation occurs approximately 6 4 repeat units for homo- donor–acceptor type respectively....

Eight novel three-coordinate boron compounds with the general formula BAr(2)L, in which Ar is mesityl and L a 7-azaindolyl- or 2,2'-dipyridylamino-functionalized aryl thienyl ligand, have been synthesized by Suzuki coupling, Ullmann condensation methods, simple substitution reactions (L = p-(2,2'-dipyridylamino)phenyl, 1; p-(2,2'-dipyridylamino)biphenyl, 2; p-(7-azaindolyl)phenyl, 3; p-(7-azaindolyl)biphenyl, 4; 3,5-bis(2,2'-dipyridylamino)phenyl, 5; 3,5-bis(7-azaindolyl)phenyl, 6;...

Light-driven H2 production is catalyzed by [Ni(P2PhN2Ph)2](BF4)2 when irradiated with visible light in water/acetonitrile mixed solvent the presence of a photosensitizer (PS) and ascorbate. The catalyst gives over 2700 turnovers 150 h, does not degrade despite photodecomposition PS.

Ligand exchange on the Co(dmgH)2(py)Cl water reduction catalyst was explored under photocatalytic conditions. The photosensitizer fluorescein connected to through axially coordinated pyridine. While this two-component complex produces H2 from visible light irradiation in presence of triethanolamine (TEOA), it is less active than a system containing separate and [CoIII(dmgH)2(py)Cl] components. NMR photolysis experiments show that Co undergoes pyridine exchange. Interestingly, glyoximate...

Introduction of S-ethyl groups in all four ortho positions azobenzene prevents reduction the azo group by intracellular glutathione, while enhancing absorptivity to ~10,000 M(-1) cm(-1) blue and green regions visible spectrum. cis-to-trans isomerization occurs thermally on minutes timescale. Further, this substitution pattern permits switching with red light, a color that is more penetrating through biological tissues than other parts

A series of halogenated boron-dipyrromethene (Bodipy) chromophores with potential applications in solar energy conversion were synthesized and characterized by steady state ultrafast laser spectroscopy. The dynamics the compared between a containing H, Br, or I at 2,6 positions Bodipy dye. parent has fluorescent lifetime (τfl) 3−5 ns, fluorescence quantum yield (Φfl) 0.56, negligible triplet yield. Bromination enhances intersystem crossing (ISC) such that τfl Φfl decrease to ∼1.2 ns 0.11,...

The dyads 3, 4, and 6, combining the Bodipy chromophore with a Pt(bpy)(bdt) (bpy = 2,2'-bipyridine, bdt 1,2-benzenedithiolate, 3 6) or Pt(bpy)(mnt) (mnt maleonitriledithiolate, 4) moiety, have been synthesized studied by UV-vis steady-state absorption, transient emission spectroscopies cyclic voltammetry. Comparison of absorption spectra voltammograms 6 those their model compounds 1a, 2, 5, 7 shows that spectroscopic electrochemical properties are essentially sum constituent chromophores,...

The synthesis and characterization of a series poly(3-alkyltellurophene)s are described. Polymers prepared by both electrochemical Kumada catalyst transfer polymerization methods. These polymers have reasonably high molecular weights (M(n) = 5.4-11.3 kDa) can be processed in manner analogous to that their lighter atom analogues. All examples exhibit red-shifted optical absorption, as well solid-state organization, evidenced absorption spectroscopy atomic force microscopy. Overall, the these...

Four dinuclear and trinuclear Cu(I) complexes that contain 2-(2'-pyridyl)benzimidazolyl derivative ligands including 1,4-bis[2-(2'-pyridyl)benzimidazolyl]benzene (1,4-bmb), 1,3-bis[2-(2'-pyridyl)benzimidazolyl]benzene (1,3-bmb), 1,3,5-tris[2-(2'-pyridyl)benzimidazolyl]benzene (tmb), 4,4'-bis[2-(2'-pyridyl)benzimidazolyl]biphenyl (bmbp) have been synthesized. The formulas of these are [Cu2(1,4-bmb)(PPh3)4][BF4]2 (1), [Cu2(1,3-bmb)(PPh3)4][BF4]2 (2), [Cu3(tmb)(PPh3)6][BF4]3 (3),...

Heteroleptic copper(I) complexes of the types [Cu(N,N)(P,P)] and [Cu(N,O)(P,P)], where (P,P) = phosphine (PPh(3)) or diphosphine (dppb, DPEPHOS, XANTPHOS), (N,N) pyrrole-2-phenylcarbaldimine, 2PyN: [Cu(2PyN)(PPh(3))(2)] (1), [Cu(2PyN) (dppb)] (2), [Cu(2PyN)(DPEPHOS)] (3), [Cu(2PyN)(XANTPHOS)] (4), indole-2-phenylcarbaldimine, 2IndN: [Cu(2IndN)(DPEPHOS)] (8), (N,O) pyrrole-2-carboxaldehyde, 2PyO: [Cu(2PyO)(DPEPHOS)] (5), [Cu(2PyO)(XANTPHOS)] (6), indole-2-carboxaldehyde, 2IndO:...

Electron-deficient π-conjugated polymers are important for organic electronics, yet the ability to polymerize electron-deficient monomers in a controlled manner is challenging. Here we show that Ni(II)diimine catalysts well suited polymerization of heterocycles. The relative stability calculated catalyst-monomer (or catalyst-chain end) complex directly influences polymerization. When predicted be most stable (139.2 kJ/mol), these display rapid reaction kinetics, leading relatively low...

A combination of noble-metal free components, a water soluble porphyrin photosensitizer zinc meso-tetrakis(1-methylpyridinium-4-yl)porphyrin chloride [ZnTMPyP4+]Cl4 (1) with cobaloxime complex [CoIII(dmgH)2(py)Cl] (2) as catalyst, creates an efficient system for photochemical hydrogen production acting under visible light 280 TONs. This is the first example catalysed H2 production.

The π-conjugated 2,5-substituted tellurophene compounds 2,5-bis(2-(9,9-dihexylfluorene))tellurophene (1) and 2,5-diphenyltellurophene (3) were synthesized through ring closing reactions of 1,4-substituted butadiyne. oxidative addition Br(2) to 1 3 was studied absorption spectroscopy, NMR, electrochemistry, X-ray crystallography, density functional theory (DFT) calculations. When adds the tellurium center spectrum shifts a lower energy. From electrochemistry DFT calculations we show that this...

We report the linear and nonlinear regions of relationship between number average molecular weight determined by gel permeation chromatography (GPC) 1H NMR end-group analysis for a series o-tolyl-initiated poly(3-hexylthiophene)s (P3HTs). For conjugated polymers with chains that are 39–138 repeat units in length (6.5–23 kDa), GPC systematically overestimates (Mn) factor 1.3 ± 0.1 (standard error), correlate manner. 138–1130 (23–188 kDa) length, we observe analysis. Static light-scattering...

Donor–acceptor polymers can store both a positive and negative charge allowing them to function as the storage material in supercapacitor device, however few have been explored for this application. Here, we describe synthesis of several donor–acceptor their electrodeposited polymer electrodes. We use differing molecular structures examine effect electron acceptor concentration show that device stability be improved significantly by increasing concentration. Further, provide computational...

The design, synthesis, and characterization of seven phthalimide-based organic π-conjugated small molecules are reported.

Three new 2,2′-dipyridylamino functionalized pyrene derivatives, 1-pyrenyl-2,2′-dipyridylamine (1), 4-(1-pyrenyl)phenyl-2,2′-dipyridylamine (2), and 4-[4′-(1-pyrenyl)biphenyl]-2,2′-dipyridylamine (3) have been synthesized fully characterized. For comparison of electronic properties, a diphenylamino molecule 4-[4′-(1-pyrenyl)biphenyl]diphenylamine (4) has also synthesized. Compounds 1–4 are bright blue emitters in solution the solid state with λmax at ∼420–460 nm high emission efficiency...

This study introduces small molecule tellurophenes that can undergo photoreductive elimination. A tellurophene compound with strong light absorption properties and extended π-conjugation, 2,5-bis[5-(N,N′-dihexylisoindigo)]tellurophene (1), has been synthesized. Halogen oxidative addition to the tellurium center from various halogen sources gives dibromo- (1Br2) dichloro- (1Cl2) adducts, leading a red-shift in optical properties. In presence of excess opposing halogen, 1Br2 1Cl2 interconvert,...