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Herein, we report the design and crystal growth of the network of K2H2mpba (1) [H4mpba = N,N′-1,3-phenylenebis(oxamic acid)], which exhibits the quite unusual (6,12)-connected alb topology. The characterization of 1 shows the following features: (i) the presence of deprotonated H2mpba2− moieties, (ii) thermal stability up to approximately 300 °C, and (iii) H2mpba2− acting as a 12-c molecular building block (MBB) and occupying the vertices of the double six-membered ring "d6R". These rings combine with potassium ions, which fill the vertices of a trigonal prism. A discussion is provided on the role played by the type of metal centre (Mn+, M = Mn, Ni, Co, Cu) and countercation [tetrabutylammonium (TBA+) or tetraethylammonium (TEA+)] in a series of structurally characterized Mn+–H2mpba2− systems described in the literature. [ABSTRACT FROM AUTHOR]

Visible‐light‐driven dual catalysis was employed to stereoselectively produce densely substituted cyclobutanes from Erlenmeyer‐Plöchl azlactones. The single‐step preparation of non‐natural amino acid dimers containing the cyclobutane moiety was achieved through a synergy between iridium photocatalysis and catalytic nickel(II) triflate as a Lewis acid. The desired 1,2‐(zeta)‐Z,E‐isomers were isolated in good yields and with high regio‐ and diastereoselectivity (in all cases, >19 : 1 d.r.). To the best of our knowledge, this is the first report of direct access to truxinic acid analogues using azlactones. Control experiments, EPR reaction monitoring, and DFT calculations suggest that the presence of a Lewis acid, combined with the use of powerful blue LEDs, plays a crucial role in the reactivity of this reaction. [ABSTRACT FROM AUTHOR]

Herein, we describe the synthesis, crystal structure, and electronic properties of {[K2(dmso)(H2O)5][Ni2(H2mpba)3]·dmso·2H2O}n (1) and [Ni(H2O)6][Ni2(H2mpba)3]·3CH3OH·4H2O (2) [dmso = dimethyl sulfoxide; CH3OH = methanol; and H4mpba = 1,3-phenylenebis(oxamic acid)] bearing the [Ni2(H2mpba)3]2− helicate, hereafter referred to as {NiII2}. SHAPE software calculations indicate that the coordination geometry of all the NiII atoms in 1 and 2 is a distorted octahedron (Oh) whereas the coordination environments for K1 and K2 atoms in 1 are Snub disphenoid J84 (D2d) and distorted octahedron (Oh), respectively. The {NiII2} helicate in 1 is connected by K+ counter cations yielding a 2D coordination network with sql topology. In contrast to 1, the electroneutrality of the triple-stranded [Ni2(H2mpba)3] 2− dinuclear motif in 2 is achieved by a [Ni(H2O)6]2+ complex cation, where the three neighboring {NiII2} units interact in a supramolecular fashion through four R22(10) homosynthons yielding a 2D array. Voltammetric measurements reveal that both compounds are redox active (with the NiII/NiI pair being mediated by OH– ions) but with differences in formal potentials that reflect changes in the energy levels of molecular orbitals. The NiII ions from the helicate and the counter-ion (complex cation) in 2 can be reversibly reduced, resulting in the highest faradaic current intensities. The redox reactions in 1 also occur in an alkaline medium but at higher formal potentials. The connection of the helicate with the K+ counter cation has an impact on the energy levels of the molecular orbitals; this experimental behavior was further supported by X-ray absorption near-edge spectroscopy (XANES) experiments and computational calculations. [ABSTRACT FROM AUTHOR]