{μ-2-[4-(Benzothia­zol-2-yl)benz­yl]-2-aza­propane-1,3-dithiol­ato-1:2κ4 S,S′:S,S′}bis­[tricarbonyl­iron(I)]

The title compound, [Fe2(C16H14N2S3)(CO)6], was prepared as the biomimetic model for the active site of iron-only hydrogenase. The structure is similar to the diiron subsite of the iron-only hydrogenase active site, and contains a diiron-aza­dithiol­ate moiety in which a boat six-membered ring is fused with a chair six-membered ring. The substituted benzyl group attached to the bridging N atom resides in an equatorial position. The sum of the C—N—C angles around this N atom [331.9 (12)°] indicates sp 3 hybridization

Bis{μ-[4-(1,3-benzothia­zol-2-yl)phen­yl]methane­thiol­ato-κ4 S,S′:S,S′}bis­[tricarbonyl­iron(I)](Fe—Fe)

The title compound, [Fe2(C14H10NS2)2(CO)6], was synthesized as a structural and biochemical model for the active site of [FeFe]-hydrogenase. The bond lengths (Fe—Fe, Fe—S and Fe—C) and angles (C—Fe—Fe and Fe—S—Fe) are within expected ranges. The S⋯S distance [2.9069 (12) Å] and the dihedral angle between two Fe—S—Fe planes [78.5 (3)°] of the butterfly-shaped Fe2S2 core are enlarged compared with related bridged dithiol­ate diiron analogues. The calculated 4-benzothia­zolebenzyl best planes are almost parallel [dihedral angle = 3.7 (7)°]

Dicarbon­yl(pyrazine-1,3-dithiol­ato-κ2 S,S′)bis­(trimethyl­phosphane-κP)iron(II)

The title compound, [Fe(C4H2N2S2)(C3H9P)2(CO)2], was obtained as a mononuclear by-product during the treatment of [Fe2(μ-S2C4N2H2)(CO)6] in excess trimethyl­phosphane. The Fe atom is six-coordinated by two thiol­ate S atoms, two phosphane P atoms and two carbonyl C atoms in a distorted octa­hedral geometry. The average Fe—C(O) distance (1.771 Å) is relatively shorter than that of its parent hexa­carbonyl­diiron compound, and differs by 0.511 Å from the average Fe—P(Me)3 distance. The five-membered FeC2S2 chelate ring plane is close to being perpendicular to the P/Fe/P plane [86.5 (2)°]

Penta­carbonyl-1κ2 C,2κ3 C-(μ-pyrazine-2,3-dithiol­ato-1:2κ4 S,S′:S,S′)(trimethyl­phosphane-1κP)diiron(I)(Fe—Fe)

In the title compound, [Fe2(C4H2N2S2)(C3H9P)(CO)5], the Fe2S2 core adopts a butterfly conformation. The PMe3 ligand is coordinated in the basal position, roughly cis to the Fe—Fe bond. The Fe—Fe distance of 2.4970 (6) Å is relatively short compared to those (ca 2.53 Å) found in another monosubstituted diiron compound. A rigid planar dithiol­ate bridge is featured, with an angle of 2.78 (1)° between the Fe—Fe bond and the normal to the pyrazine-2,3-dithiol­ate plane

High-Mobility Semiconducting Polymers With Different Spin Ground States

Organic semiconductors with high-spin ground states are fascinating because they could enable fundamental understanding on the spin-related phenomenon in light element and provide opportunities for organic magnetic and quantum materials. Although high-spin ground states have been observed in some quinoidal type small molecules or doped organic semiconductors, semiconducting polymers with high-spin at their neutral ground state are rarely reported. Here we report three high-mobility semiconducting polymers with different spin ground states. We show that polymer building blocks with small singlet-triplet energy gap (ΔES-T) could enable small ΔES-T gap and increase the diradical character in copolymers. We demonstrate that the electronic structure, spin density, and solid-state interchain interactions in the high-spin polymers are crucial for their ground states. Polymers with a triplet ground state (S = 1) could exhibit doublet (S = 1/2) behavior due to different spin distributions and solid-state interchain spin-spin interactions. Besides, these polymers showed outstanding charge transport properties with high hole/electron mobilities and can be both n- and p-doped with superior conductivities. Our results demonstrate a rational approach to obtain high-mobility semiconducting polymers with different spin ground states

Modification of TiO_2 Nanoparticles with Organodiboron Molecules Inducing Stable Surface Ti^(3+) Complex

As one of the most promising semiconductor oxide materials, titanium dioxide (TiO_2) absorbs ultraviolet (UV) light but not visible light. To address this limitation, the introduction of Ti^(3+) defects represents a common strategy to render TiO_2 visible-light-responsive. Unfortunately, current hurdles in Ti^(3+) generation technologies impeded the widespread application of Ti^(3+) modified materials. Herein, we demonstrate a simple and mechanistically distinct approach to generating abundant surface-Ti^(3+) sites without leaving behind oxygen vacancy and sacrificing one-off electron donors. In particular, upon adsorption of organodiboron reagents onto TiO_2 nanoparticles, spontaneous electron injection from the dibron-bound O^(2-) site to adjacent Ti^(4+) site leads to an extremely stable blue surface Ti^(3+)‒O^(-•) complex. Notably, this defect generation protocol is also applicable to other semiconductor oxides including ZnO, SnO_2, Nb_2O_5 and In_2O_3. Furthermore, the as-prepared photoelectronic device using this strategy affords 10^3 fold higher visible light response, and the fabricated perovskite solar cell shows an enhanced performance

Polysaccharide from Sepia esculenta ink and cisplatin inhibit synergistically proliferation and metastasis of triple-negative breast cancer MDA-MB-231 cells

Objective(s): This paper aims to investigate synergistic inhibition of polysaccharide from Sepia esculenta ink (SIP), a newly isolated marine polysaccharide in our laboratory, on breast cancer MDA-MB-231 cells exposed to cisplatin. Materials and Methods: Cell viability of MDA-MB-231 cells was determined by CCK 8 assay. Median-effect concentration was analyzed using Chou-Talalay method that was also subjected to determine cell inhibition ratio and combined index, as well as interaction between SIP and cisplatin. Proliferation and migration abilities were detected with plate colony formation assay and cell wound scratch assay, respectively. Expression of MMP-2 and MMP-9 proteins was measured with Western blot assay. Results: Data showed that SIP not only suppressed proliferation and migration of MDA-MB-231 cells, and expression of MMP-2 and MMP-9 proteins, also promoted inhibition of cisplatin on proliferation, migration and MMPs expression of MDA-MB-231 cells, which indicates synergy inhibition of drug combination of SIP and cisplatin on breast cancer cells. The median-effect concentrations of cisplatin and SIP were 4.9 and 1659.6 μg/ml, respectively. Whereas the concentration of combination drug was 158.5 μg/ml. The data indicated that drug combination can decrease dosages of the two single agents, especially the usual dosage of cisplatin. Conclusion: This research demonstrated that SIP repressed proliferation and metastasis of MDA-MB-231 cells and promoted anticancer effect of cisplatin on the breast cancer cells. The data suggested that SIP is a potential natural drug that can be used as an auxiliary medicine alongside chemotherapy in treating breast cancer

Non-equivalent role of TM2 gating hinges in heteromeric Kir4.1/Kir5.1 potassium channels

Comparison of the crystal structures of the KcsA and MthK potassium channels suggests that the process of opening a K+ channel involves pivoted bending of the inner pore-lining helices at a highly conserved glycine residue. This bending motion is proposed to splay the transmembrane domains outwards to widen the gate at the “helix-bundle crossing”. However, in the inwardly rectifying (Kir) potassium channel family, the role of this “hinge” residue in the second transmembrane domain (TM2) and that of another putative glycine gating hinge at the base of TM2 remain controversial. We investigated the role of these two positions in heteromeric Kir4.1/Kir5.1 channels, which are unique amongst Kir channels in that both subunits lack a conserved glycine at the upper hinge position. Contrary to the effect seen in other channels, increasing the potential flexibility of TM2 by glycine substitutions at the upper hinge position decreases channel opening. Furthermore, the contribution of the Kir4.1 subunit to this process is dominant compared to Kir5.1, demonstrating a non-equivalent contribution of these two subunits to the gating process. A homology model of heteromeric Kir4.1/Kir5.1 shows that these upper “hinge” residues are in close contact with the base of the pore α-helix that supports the selectivity filter. Our results also indicate that the highly conserved glycine at the “lower” gating hinge position is required for tight packing of the TM2 helices at the helix-bundle crossing, rather than acting as a hinge residue