Trifid or double-notched aortic Doppler: an aortic ‘Trishula’ sign

Trifid or double-notched aortic Doppler: an aortic ‘Trishula’ sig

Scimitar syndrome with hemi-cor triatriatum

Scimitar syndrome with hemi-cor triatriatu

At the Borderline between Metal–Metal Mixed Valency and a Radical Bridge Situation: Four Charge States of a Diruthenium Complex with a Redox-Active Bis(<i>mer</i>-tridentate) Ligand

The complex ions [L³Ru­(μ,η³:η³-BL)­RuL³]^<i>n</i>+ (<b>1</b>^{<b><i>n</i>+</b>}, L³ = 4,4′,4″-tri-<i>tert</i>-butyl-2,6,2′,6″-terpyridine and H₂BL^2– = 1,2-bis­(salicyloyl)­hydrazide(2−)) were isolated with PF₆^– or ClO₄^– counterions (<i>n</i> = 1) and as bis­(hexafluorophosphate) (<i>n</i> = 2). Structural, electrochemical, and spectroscopic characterization reveals the monocation as intermediate (<i>K</i>_c = 10^8.2) in the three-step reversible redox system <b>1</b>^{<b>0/+/2+/3+</b>}. The <b>1</b>^<b>+</b> ion has the molecule-bridged (Ru- - -Ru 4.727 Å) ruthenium centers involved in five- and six-membered chelate rings, and it exhibits long-wavelength absorptions at λ_max 2240, 1660, and 1530 nm (ε_max = 1000, 3000, and 8000 M^–1 cm^–1, respectively), which would be compatible with a Ru^IIIRu^II mixed-valent situation or with a coordinated radical ion bridge. In fact, EPR and DFT analysis of <b>1</b>^<b>+</b> reveals that the spin is equally distributed over the ligand bridge and over both metals. The oxidized paramagnetic ions <b>1</b>^<b>2+</b> and <b>1</b>^<b>3+</b> have been studied by ¹H NMR and EPR and by TD-DFT supported UV–vis–NIR and MIR (mid-IR) spectroelectrochemistry. The capacity of various kinds of bis­(<i>mer</i>-tridentate) bridging ligands (π donors or π acceptors, cyclometalated or noncyclometalated) for mediating metal–metal interactions is discussed

Molecular Engineering of Self-Assembling Diphenylalanine Analogues Results in the Formation of Distinctive Microstructures

Diphenylalanine is one of the most studied building blocks in organic supramolecular chemistry, forming ordered assemblies with unique mechanical, optical, piezoelectric, and semiconductive properties. These structures are being used for diverse applications, including energy storage, biosensing, light emission, drug delivery, artificial photosynthesis, and chemical propulsion. To increase the structural diversity of this dipeptide building block, three previously unreported analogues in which the aliphatic chain between the peptide backbone and the phenyl ring was gradually lengthened were synthesized. Each dipeptide self-assembled into unique microstructures, differing in morphology, which ranged from flat plates to long microrods to flattened microplanks. The structures were also found to possess distinctive optical properties. Furthermore, X-ray crystallography of each of the three diphenylalanine analogues presented distinctive molecular arrangements. The remarkable differences between each dipeptide in the intermolecular interactions they formed provide insight into the physicochemical mechanisms of self-assembly and, in addition, indicate the biological significance of the single methylene bridge of phenylalanine

Molecular Engineering of Self-Assembling Diphenylalanine Analogues Results in the Formation of Distinctive Microstructures

Diphenylalanine is one of the most studied building blocks in organic supramolecular chemistry, forming ordered assemblies with unique mechanical, optical, piezoelectric, and semiconductive properties. These structures are being used for diverse applications, including energy storage, biosensing, light emission, drug delivery, artificial photosynthesis, and chemical propulsion. To increase the structural diversity of this dipeptide building block, three previously unreported analogues in which the aliphatic chain between the peptide backbone and the phenyl ring was gradually lengthened were synthesized. Each dipeptide self-assembled into unique microstructures, differing in morphology, which ranged from flat plates to long microrods to flattened microplanks. The structures were also found to possess distinctive optical properties. Furthermore, X-ray crystallography of each of the three diphenylalanine analogues presented distinctive molecular arrangements. The remarkable differences between each dipeptide in the intermolecular interactions they formed provide insight into the physicochemical mechanisms of self-assembly and, in addition, indicate the biological significance of the single methylene bridge of phenylalanine