The synthesis of ethyne-linked porphyrin nanorings has been achieved by template-directed Sonogashira coupling. cyclic hexamer and octamer are predicted density functional theory to adopt low symmetry conformations, due dihedral twists between neighboring units, but their symmetries effectively D6h D8h, respectively, in solution 1H NMR. fluorescence spectra indicate that the singlet excited states these highly delocalized.

Abstract Cumulenes are sometimes described as “metallic” because an infinitely long cumulene would have the band structure of a metal. Herein, we report single‐molecule conductance series cumulenes and analogues, where number consecutive C=C bonds in core is n =1, 2, 3, 5. The [ ]cumulenes with =3 5 almost same conductance, they both more conductive than alkene ( =1). This remarkable molecular normally falls exponentially length. allene =2) much lower, its twisted geometry. Computational...

Most macrocycles are made from a simple repeat unit, resulting in high symmetry. Breaking this symmetry allows fine-tuning of the circumference, providing better control host-guest behavior and electronic structure. Here, we present template-directed synthesis two unsymmetrical cyclic porphyrin hexamers with both ethyne (C2) butadiyne (C4) links, compare these nanorings symmetrical analogues six or links. Inserting extra carbon atoms into smaller nanoring causes spectacular change binding...

Enhanced thermodynamic stability is a fundamental characteristic of aromatic molecules, yet most previous studies stabilization energy (ASE) have been limited to small rings with up 18 π-electrons. Here we demonstrate that ASE can be detected experimentally in π-conjugated porphyrin nanorings Hückel circuits 76–108 This conclusion supported by analyzing redox potentials calculate the change for isodesmic reactions convert an ring antiaromatic or vice versa. It also barriers conformational...

Abstract Cumulenes are sometimes described as “metallic” because an infinitely long cumulene would have the band structure of a metal. Herein, we report single‐molecule conductance series cumulenes and analogues, where number consecutive C=C bonds in core is n =1, 2, 3, 5. The [ ]cumulenes with =3 5 almost same conductance, they both more conductive than alkene ( =1). This remarkable molecular normally falls exponentially length. allene =2) much lower, its twisted geometry. Computational...

The link between allosteric cooperativity and template-directed synthesis has been investigated by studying complexes in which two oligopyridine ligands bind inside a zinc porphyrin nanoring stacked arrangement. binding of 6-porphyrin to tridentate (with s-triazine or benzene cores) occurs with high negative (α ≈ 10-3-10-4). Formation constants for 1:1 1:2 were determined UV-vis-NIR denaturation titration, using pyridine as competing ligand, factors confirmed NMR spectroscopy. rate formation...

Phthalocyanines (Pcs) are used as sensitizers in dye-sensitized solar cells (DSSCs) because of their stability and intense absorption the red near-IR regions. Impressive progress has been made photovoltaic efficiencies by introduction bulky peripheral substituents to help suppress macrocycle aggregation. To reach benchmark reported for other related dyes, new designs need be explored. Single carboxy-ZnPc regioisomers substituted at non-peripheral positions rigid aryl groups have now studied,...

A new design of nonaggregated zinc(II) carboxyphthalocyanines with potential application in dye-sensitized solar cells has been developed. It is based on the introduction bulky and rigid aryl groups at three α positions macrocycle. The synthesis carried out following a convergent route which are introduced by Suzuki–Miyaura cross-coupling reaction preformed triiodophthalocyanine derivative. Two regioisomers this α-triaryl-β-carboxyphthalocyanine could be isolated column chromatography.

The luminescence and electroluminescence of an ethyne-linked zinc(ii) porphyrin pentamer have been investigated, by testing blends in two different conjugated polymer matrices, at a range concentrations. best results were obtained for with the PIDT-2TPD, loading 1 wt%. This host matrix was selected because excellent overlap between its emission spectrum low-energy region absorption oligomer leads to efficient energy transfer. Thin films this blend exhibit intense fluorescence near-infrared...

A family of inherently chiral nonplanar aromatic chromophores, comprising Subphthalocyanines bearing fluorenone-fused units (SubFcs), have been prepared by an innovative one-pot synthesis, which relies on the standard cross-cyclotrimerization phthalonitriles followed intramolecular Friedel–Crafts acylation. Their Q-band absorption experiences a ca. 20 nm red shift per fused fluorenone as consequence enlarged conjugated π-system.

Abstract To date β‐aryloxy‐substituted designs have led to the best results in phthalocyanine‐sensitized solar cells (Pc‐SCs) because of their low aggregation properties. By incorporating bulky semiflexible 2,6‐diphenylphenoxy group at three α‐positions Pc, different regioisomers were separated by column chromatography and photovoltaic performance was thoroughly studied. Efficiencies range 1.9–4.1 % found, thus demonstrating importance steric interaction between substituents semiconductor...

The spin delocalization in the radical cations of a series ethyne-linked oligoporphyrins was investigated using EPR spectroscopy. room-temperature spectral envelope for these oligomers deviates significantly from benchmark N-0.5 trend line width expected completely delocalized density, contrast to butadiyne-linked analogues measured previously. Here, we show, DFT calculations and complementary low-temperature ENDOR measurements, that this deviation is primarily driven by more pronounced...

Phthalocyanines (Pc) are well-known light-harvesting compounds. However, despite the tremendous efforts on phthalocyanine synthesis, achieved energy conversion efficiencies for Pc-based dye-sensitized solar cells moderate. To cast light factors reducing efficiency, we have undertaken a time-resolved spectroscopy study of primary photoinduced reactions at semiconductor-Pc interface. ZnO nanorods were chosen as model semiconductor substrate with enhanced specific surface area. The use...

Aromaticity is an important concept for predicting electronic delocalisation in molecules, particularly designing organic semiconductors and single-molecule devices. It most simply defined by the ability of a cyclic molecule to sustain ring current when placed magnetic field. Hückel’s rule states that if has [4n+2] π-electrons, it will be aromatic with induced magnetisation opposes external field inside ring, whereas 4n antiaromatic opposite magnetisation. This reliably predicts behaviour...

Abstract Subphthalocyanine (SubPc) chemistry has been limited so far by their high sensitivity toward strong nucleophiles. In particular, the substitution of axial chlorine atom a nucleophilic group in case less‐reactive SubPcs, such as those bearing electron‐withdrawing peripheral substituents, presents some limitations and requires harsh conditions. By taking advantage electrophilic character DIBAL‐H, it possible to prepare for first time SubPc‐hydride derivatives that exhibit reactivity...

Abstract A novel tetrabenzotriazaporphyrin (TBTAP) bearing an anchoring carboxy‐phenyl group at the meso ‐carbon position ( TT260 ) was synthesized by efficient method, which involves crossover condensation between phthalonitrile and aminoisoindoline precursors. Its optical electrochemical properties were also investigated together with its use as sensitizer in dye‐sensitized solar cells (DSSCs). The performance of compared a benchmark molecule TT1 , similar bulky tert‐ butyl groups...

A new carboxy-Zn(II)phthalocyanine bearing rigid 2,6-diarylphenyl peripheral substituents linked to the macrocycle through alkynyl spacers has been prepared by a convergent approach, which implies triple Sonogashira coupling between formyltriiodoZnPc and corresponding terminal alkyne. Indeed, introduction of this type [Formula: see text]-conjugated accounts for remarkable red shift phthalocyanine Q-band until ca. 700 nm. However, aggregation phenomena could not be supressed may explain...

We report the optical resolution of inherently chiral, bowl-shaped subphthalocyanines (SubPcs) using BINOL-based chiral auxiliaries. Additionally, unprecedented bowl-to-bowl inversion SubPc macrocycle is observed under specific conditions.

<div><p>Aromaticity is an important concept for predicting electronic delocalisation in molecules, particularly designing organic semiconductors and single-molecule devices. It most simply defined by the ability of a cyclic molecule to sustain ring current when placed magnetic field. Hückel’s rule states that if has [4n+2] π-electrons, it will be aromatic with induced magnetisation opposes external field inside ring, whereas 4n antiaromatic opposite magnetisation. This reliably...

Phthalocyanines (Pcs) [1-3] are among the few molecules that reveal an intense NIR absorption and therefore, constitute promising dyes in molecular photovoltaics [4]. Pcs have emerged also as excellent light harvesting antennas for incorporation into donor-acceptor systems, mainly connection with carbon nanostructures acceptor moieties [3]. During this talk overview of results obtained by our group Madrid will be given. References 1. G. de la Torre, C. Claessens, T. Torres, Chem. Commun....

Abstract not Available.

Aromaticity is an important concept for predicting electronic delocalisation in molecules, particularly designing organic semiconductors and single-molecule devices. It most simply defined by the ability of a cyclic molecule to sustain ring current when placed magnetic field. Hückel’s rule states that if has [4n+2] π-electrons, it will be aromatic with induced magnetisation opposes external field inside ring, whereas 4n antiaromatic opposite magnetisation. This reliably predicts behaviour...