Triplet-triplet sensitizing within pyrene-based COO-BODIPY: a breaking molecular platform for annihilating photon upconversion.

We envisioned a new approach for achieving triplet-triplet annihilation-assisted photon upconversion based on the rational design of a heavy-atom-free, all-organic and photoactivatable triplet-triplet synergistic multichromophoric molecular assembly. This single molecular architecture is easily built by covalently anchoring triplet-annihilator units (pyrenes) to a triplet-photosensitizer moiety (BODIPY), to improve the effectiveness and probability of the required triplet-triplet energy transfer and the ulterior triplet-triplet annihilation. This unprecedented design takes advantage of the high synthetic accessibility and chemical versatility of the COO-BODIPY scaffold. The laser-induced photophysical characterization, assisted by computational simulations (quantum mechanics calculations at single molecular level and molecular dynamics in a solvent cage), identifies the key factors to finely control the intersystem crossing and reverse intersystem crossing probability, pivotal to improve energy transfer efficiency between the involved triplet states. Likewise, theoretical simulations highlight the relevance of the new photoactivable chromophoric design to promote intra- and inter-molecular triplet-triplet annihilation towards enhanced photon upconversion, yielding noticeable fluorescence from pyrene units even under unfavorable conditions (aerated solutions of low concentration at room temperature). The understanding of the complex dynamics sustained by this single molecular architecture could approach the next generation of chemically accessible and low-cost materials enabling fluorescence by photon upconversion mediated by triplet-triplet annihilation.

[Endoscopic tunneling procedures in achalasia and gastroparesis]. / Endoskopische Tunnelungsverfahren bei Achalasie und Gastroparese.

Since the first publication of peroral endoscopic myotomy (POEM) by Haruhiro Inoue et al. in 2008 in Japan, various novel endoscopic procedures have been established, which are performed after iatrogenic creation of a submucosal tunnel as a "new space" 1. Through the artificially formed access in the tela submucosa, interventions in the muscular layer of the esophagus and stomach can be performed while carefully sparing the mucosal layer 2. These include, peroral myotomy of the esophageal muscle layer in patients with achalasia (POEM) and myotomy of the pylorus in patients with gastroparesis (antropyloromyotomy, G-POEM). Further indications include splitting of Zenker diverticulum in POEM technique ("Z-POEM") as well as the removal of subepithelial tumors (STER: submucosal tunneling, endoscopic resection). The long-term therapeutic success (with > 80 % response) of these innovative procedures has now been proven by controlled studies, especially in achalasia 2 3 4 5 6.

Multichromophoric COO-BODIPYs: an advantageous design for the development of energy transfer and electron transfer systems.

COO-BODIPYs are highlighted as cutting edge scaffolds for easy access to a new generation of multichromophoric architectures with enhanced (photo)chemical stability, showing either boosted capability for excitation energy transfer, glow fluorescence and laser emission, or photoinduced electron transfer. The new finding paves the way for the rapid development of smarter organic dyes for advancing photonics and optoelectronics.

BCl3-Activated Synthesis of COO-BODIPY Laser Dyes: General Scope and High Yields under Mild Conditions.

A general and straightforward method for the synthesis of COO-BODIPYs from F-BODIPYs and carboxylic acids is established. The method is based on the use of boron trichloride to activate the involved substitution of fluorine, which leads to high yields through rapid reactions under soft conditions. This mild method opens the way to unprecedented laser dyes with outstanding efficiencies and photostabilities, which are difficult to obtain by the current methods.