Oxidation of a directly meso-meso linked cyclic porphyrin tetramer 2 gave sheet 3. The symmetric square structure 3 is indicated by its simple 1H NMR spectrum that exhibits only two signals for the beta-protons. absorption displays characteristic Soret-like broad bands and weak Q-bands, magnetic circular dichroism (MCD) negative Faraday A term at 762 nm band as rare case, indicating transition from nondegenerate level to degenerate level. slightly longer S1-state (1.1 ps) smaller TPA cross...

UV−vis irradiation of an organotellurium chain transfer agent in the presence vinyl monomers leads to formation highly controlled living polymers with predetermined number average molecular weights and narrow weight distributions.

The effects of photoirradiation in controlled and living radical polymerization (LRP), namely nitroxide-mediated (NMP), atom-transfer (ATRP), cobalt-mediated (CMRP), reversible addition-fragmentation chain transfer (RAFT), organoiodine-mediated (IRP), organotellurium-mediated (TERP), are summarized. As the conventional polymerization, has been used for generating radicals under mild conditions LRP methods. In addition to this use, is also overcome difficulties characteristic each method,...

Directly meso-meso linked porphyrin rings CZ4, CZ6, and CZ8 that respectively comprise four, six, eight porphyrins have been synthesized in a stepwise manner from 5,10-diaryl zinc(II) building block. Symmetric cyclic structures indicated by their very simple (1)H NMR spectra exhibit only single set of absorption display characteristic broad nonsplit Soret band around 460 nm. Energy minimized calculated at the B3LYP/6-31G* level indicate dihedral angle between neighboring decreases order CZ6...

The synthesis and photophysical properties of butadiyne-linked chlorophyll porphyrin dimers in toluene solution several self-assembled prismatic structures are described. butadiyne linkage between the 20-positions macrocycles results new electronic transitions polarized along long axes dimers. These greatly increase ability these to absorb solar spectrum over a broad wavelength range. Femtosecond transient absorption spectroscopy reveals relative rate rotation around bond joining them....

An efficient and simple method for the synthesis of symmetric macromolecules by photoinduced switching from radical polymerization to a coupling reaction is reported. Structurally well-defined telechelic polyisoprenes ABA-triblock copolymers were prepared successive organotellurium-mediated living (TERP) under thermal conditions, followed polymer-end photoirradiation.

A novel method to determine the termination mechanism of radical polymerization, i.e., selectivity between disproportionation (Disp) and combination (Comb), is developed. The relies on product analyses reaction polymer-end radicals, which are generated from structurally well-controlled living polymers, molecular weight end-group structure polymers by GPC, mass spectroscopy, 1H NMR unambiguously determined contribution two competing pathways. in polymerization methyl methacrylate (MMA)...

Highly efficient synthesis of meso,meso-dibromo doubly and triply fused diporphyrins has been achieved through a powerful oxidative coupling mediated by AuCl3-AgOTf combination. In addition, palladium-catalyzed debromination meso-bromoporphyrins developed. This protocol enables employment bromine as protecting group for the reactive meso-position porphyrins.

Two-photon absorption (TPA) properties and energy relaxation dynamics of meso-β doubly linked Ni(II) porphyrin arrays (DLNin, n = 2−5) in CHCl3 have been investigated. DLNin exhibits near-IR-extended bands up to 1000 nm enlarged TPA cross-section values without any one-photon contribution as the number subunits increases mainly due an elongation effective π-conjugation length. Especially, case pentamer, DLNi5 had a value 41 000 GM, which is largest per subunit (σ(2)/n ∼ 8000 GM) among...

Abstract We report the synthesis and characterization of L‐ T‐shaped porphyrin tapes as extensible structural motifs two‐dimensionally extended tapes. The two‐photon absorption (TPA) cross‐section values ( σ (2) ) for well those linear trimeric tetrameric were measured by an open‐aperture Z‐scan method at 2300 nm, a wavelength which one‐photon contribution is either zero or almost negligible. Under these conditions, tape trimer tetramer determined to be 18 500 41 200 GM, respectively. value...

The termination mechanism of the radical polymerization acrylates, namely selectivity disproportionation (Disp) and combination (Comb) between polymer end radicals, is unambiguously determined by reaction polyacrylate radicals generated from corresponding "living" organotellurium ω-end polymer. While textbooks describe occurrence Comb, at 25 °C exclusively gives Disp products. Ab initio molecular dynamics suggests that products form two pathways: direct a novel stepwise process involves...

Abstract The first successfully controlled radical polymerization (CRP) of ethylene is reported using several organotellurium chain‐transfer agents (CTAs) under mild conditions (70 °C, 200 bar ethylene) within the concept organotellurium‐mediated (TERP). In contrast to preceding works on CRPs applying reversible addition–fragmentation (RAFT), TERP system provided a high livingness and chain‐end functionalization polyethylene chains. Molar‐mass distributions with dispersities between 1.3 2.1...

Reusable and removable adhesives have been synthesized using dynamic Diels–Alder chemistry with high lap shear strength, good reusability easy removability.

The oxidation of 5,15-bis(3,5-di-tert-butylphenyl) Ni(II)-porphyrin 1b with Sc(OTf)3 and DDQ led to production meso-β doubly linked tapes that have large π-electronic communications over the arrays.

[reaction: see text] Regioselectivity of the oxidative coupling 5,10,15-triarylporphyrin metal complexes with DDQ-Sc(OTf)(3) was dependent on central and meso-aryl substituent. Oxo-quinoidal porphyrin obtained from Ni(II) under same conditions.

The effects of azo initiators on the structures α-polymer chain ends in organotellurium-, organostibine-, organobismuthine-, and organoiodine-mediated living radical polymerizations (TERP, SBRP, BIRP, IRP, respectively) reversible addition–fragmentation transfer polymerization (RAFT) were quantitatively analyzed for first time. These methods predominantly, or exclusively, follow degenerative (DT) mechanism activation deactivation dormant species. An external species is required to initiate...

A low-intensity (6 W) light-emitting diode (LED) effectively activated an organotellurium chain transfer agent and the dormant species, promoting well-controlled radical polymerization. The use of LED provided many advantages over previously reported high-intensity Hg lamp, including high energy efficiency during polymerization, easy availability low-cost light source. Structurally well-defined poly(methyl methacrylate), acrylate), polystyrene, with narrow molecular weight distributions,...

The mechanism of the Cu(I)/Cu(0)-mediated reductive coupling reactions bromine-terminated polymer chain-end radicals, so-called atom-transfer radical (ATRC), is studied. Poly(methyl acrylate) (PMA), poly(methyl methacrylate) (PMMA), and polystyrene (PSt), prepared by polymerization (ATRP), were activated an excess amount Cu(I)Br Cu(0) in presence tris[2-(dimethylamino)ethyl]amine (Me6TREN), structural analyses resulting products deuterium-labeling experiments unambiguously determined...

Epoxy resins incorporating aromatic disulfide bonds demonstrated improved adhesive properties with increasing temperature below their glass transition points.

Abstract Liquid marble (LM) is a droplet that wrapped by hydrophobic solid particles, which behave as non‐wetting soft solid. Based on these properties, LM can be applied in fluidics and device applications. A wide variety of functional particles have been synthesized to form LMs. However, the formation multifunctional LMs integrating several types challenging. Here, general strategy for flexible patterning surfaces patchwork‐like design reported. It shown switch their macroscopic behavior...

We have investigated the relationship between photophysical properties and structures of a series directly linked zinc(II) porphyrin dimers (mmZ2, mbZ2, bbZ2) using time-resolved spectroscopic measurements theoretical calculations. Their unique characters such as CT nature torsional motion are caused by interporphyrin interactions steric effects, respectively, which can be fully understood in terms three structural factors: linking position, dihedral angle, linkage length. The orthogonal...

The termination mechanism of radical polymerization, that is, disproportionation (Disp) versus combination (Comb), determines the chain length and end-group structure resulting polymer as well properties, yet factors governing are still unclear. Furthermore, no attempts have been made to control mechanism. Here, effects temperature viscosity on methyl methacrylate (MMA) styrene (St) polymerization were elucidated by using small molecular model-radicals corresponding radicals in various...