Crystal structure of a dicationic PdII dimer containing a 2-[(diisopropylphosphanyl)methyl]quinoline-8-thiolate pincer ligand

A dicationic PdII dimer, bis{2-[(diisopropylphosphanyl)methyl]quinoline-8-thiolato}palladium(II) bis(hexafluoridoantimonate) dichloromethane monosolvate, [Pd2(C32H42N2P2S2)](SbF6)2·CH2Cl2, containing a 2-[(diisopropylphosphanyl)methyl]quinoline-8-thiolate pincer ligand, was isolated and its crystal structure determined. The title compound crystallizes in the orthorhombic space group Pbca. A dimeric structure is formed by bridging coordination of the S atoms. The geometry of the butterfly-shaped Pd2S2 core is bent, with a hinge angle of 108.0 (1)° and a short Pd...Pd distance of 2.8425 (7) Å. These values are the lowest measured compared to ten dicationic dimers with a Pd2S2 core featuring sulfur atoms embedded in a chelating ligand. One of the two hexafluoridoantimonate anions is disordered over two sets of positions with site-occupancy factors of 0.711 (5) and 0.289 (5). The crystal structure is stabilized by many C—H...F and C—H...π interactions, forming a supramolecular network.

Biochemical Characterization and Crystal Structure of a Novel NAD+-Dependent Isocitrate Dehydrogenase from Phaeodactylum tricornutum

The marine diatom Phaeodactylum tricornutum originated from a series of secondary symbiotic events and has been used as a model organism for studying diatom biology. A novel type II homodimeric isocitrate dehydrogenase from P. tricornutum (PtIDH1) was expressed, purified, and identified in detail through enzymatic characterization. Kinetic analysis showed that PtIDH1 is NAD+-dependent and has no detectable activity with NADP+. The catalytic efficiency of PtIDH1 for NAD+ is 0.16 μM−1·s−1 and 0.09 μM−1·s−1 in the presence of Mn2+ and Mg2+, respectively. Unlike other bacterial homodimeric NAD-IDHs, PtIDH1 activity was allosterically regulated by the isocitrate. Furthermore, the dimeric structure of PtIDH1 was determined at 2.8 Å resolution, and each subunit was resolved into four domains, similar to the eukaryotic homodimeric NADP-IDH in the type II subfamily. Interestingly, a unique and novel C-terminal EF-hand domain was first defined in PtIDH1. Deletion of this domain disrupted the intact dimeric structure and activity. Mutation of the four Ca2+-binding sites in the EF-hand significantly reduced the calcium tolerance of PtIDH1. Thus, we suggest that the EF-hand domain could be involved in the dimerization and Ca2+-coordination of PtIDH1. The current report, on the first structure of type II eukaryotic NAD-IDH, provides new information for further investigation of the evolution of the IDH family.

Crystal structure of di-μ-trihydro(pentafluorophenyl)borato-tetrakis(tetrahydrofuran)disodium

The title compound, [Na(μ-C6F5BH3)(C4H8O)2]2, represents a dimeric structure of sodium and organoborohydride, located about a centre of inversion. The Na...B distances of 2.7845 (19) and 2.7494 (18) Å were apparently longer than the Li...B distances (2.403–2.537 Å) of the lithium organotrihydroborates in the previous reports. Moreover, an interaction between the sodium atom and one fluorine atom on the 2-position of the benzene ring is observed [Na—F = 2.6373 (12) Å]. In the crystal, the dimeric molecules are stacked along the b-axis via a π–π interaction between the benzene rings.

Synthesis of New 7,8-Dioxa[6]helicenes with Triazole Rings as Potential Molecular Tweezers

This study introduces new triazole-linked host compounds, which have been synthesized from 7,8-dioxa-bisnaphthalene and 7,8-dioxa[6]helicenes. These compounds have different cavities depending on being ‘v’-shaped or helicene structures. The dimeric structure of 7,8-dioxa-bisnaphthalene has also been obtained and crystal structure analysis confirmed that it contains an unusual seven-membered dihydrooxepine ring. All synthesized compounds can act as molecular tweezers for organic molecules and also metal ions.

Pressure-induced remarkable luminescence switch of a dimer form of donor–acceptor–donor triphenylamine (TPA) derivative

Pressure-induced remarkable responsive behaviours can be realized in the D–A–D molecule TPA-Py-CN with a dimeric structure.