Syntheses and Crystal Structures of Two Cadmium Methanetetrabenzoates Featured by Open Framework and Infinite Layers

International audienceColourless single crystals of Cd2[μ8-MTB]*3H2O*DMF (1) were prepared in DMF/H2O solution. 1: Space group C2/c (no. 15) with a = 1821.30(6), b = 2175.08(6), c = 1269.87(4) pm, β = 129.684(1)°. The connection between the methane-p-benzoate tetraanions (MTB4−) and the Cd2+ cations leads to a three-dimensional framework with channels extending along [ 10] and [110] with openings of 670 pm × 360 pm. The channel-like voids accommodate water molecules and N,N-dimethylformamide (DMF) molecules not bound to Cd2+. Colourless single crystals of [Cd4(2,2′-bipy)4(μ7-MTB)2]*7DMF (2) were prepared in DMF in the presence of 2,2'-bipyridine. 2: Space group P (no. 2) with a = 1224.84(4), b = 1418.85(5), c = 2033.49(4) pm, α = 85.831(2)°, β = 88.351(2)°, γ = 68.261(1)°. The coordination of MTB4− to Cd2+ results in infinite layers parallel to (001). The layers, not connected by any hydrogen bonds, contain small openings of about 320 pm × 340 pm

Targeted discovery of tetrapeptides and cyclic polyketide-peptide hybrids from a fungal antagonist of farming termites

Herein, we report the targeted isolation and characterization of four linear nonribosomally synthesized tetrapeptides (pseudoxylaramide A–D) and two cyclic nonribosomal peptide synthetase- polyketide synthase-derived natural products (xylacremolide A and B) from the termite-associated stowaway fungus Pseudoxylaria sp. X187. The fungal strain was prioritized for further metabolic analysis based on its taxonomical position and morphological and bioassay data. Metabolic data were dereplicated based on high-resolution tandem mass spectrometry data and global molecular networking analysis. The structure of all six new natural products was elucidated based on a combination of 1D and 2D NMR analysis, Marfey’s analysis and X-ray crystallography.The Deutsche Forschungsgemeinschaft (DFG)https://chemistry-europe.onlinelibrary.wiley.com/journal/14397633am2020BiochemistryGeneticsMicrobiology and Plant Patholog

Roles played by carbene substituents during ligand transfer reactions between tungsten fischer carbene complexes and [Pt(COD)Cl2]

Please read abstract in the article.RESEARCH DATA FOR THE ARTICLE: Available at Cambridge Crystallographic Data Center. Crystallographic data: CCDC 1917582: Experimental Crystal Structure Determination (https://www.ccdc.cam.ac.uk/structures/search?id=doi:10.5517/ccdc.csd.cc22cdhc&sid=DataCite)CCDC 1917583: Experimental Crystal Structure Determination (https://www.ccdc.cam.ac.uk/structures/search?id=doi:10.5517/ccdc.csd.cc22cdjd&sid=DataCite)CCDC 1917581: Experimental Crystal Structure Determination (https://www.ccdc.cam.ac.uk/structures/search?id=doi:10.5517/ccdc.csd.cc22cdgb&sid=DataCite)The Alexander von Humboldt Foundation; the University of Pretoria and the National Research Foundation (SA).http://www.elsevier.com/locate/jorganchem2022-10-01hj2022Chemistr

Ligand effects on the electrochemical behavior of [Fe2(CO)5(L){μ-(SCH2)2(Ph)P<img border='0' src='http://www.rsc.org/images/entities/h2_char_e001.gif' alt='[double bond, length as m-dash]'/>O}] (L = PPh3, P(OEt)3) hydrogenase model complexes

International audienceIn this paper we study the influence of substituting one CO ligand in [Fe2(CO)6{μ-(SCH2)2(Ph)P[double bond, length as m-dash]O}] (1) by better σ-donor L ligands affording [Fe2(CO)5(L){μ-(SCH2)2(Ph)P[double bond, length as m-dash]O}] {L = PPh3 (2) and P(OEt)3 (3)} in relation to the steric interactions and the voltammetric behavior. Cyclic voltammetric investigations under N2 and CO showed remarkable differences in the electrochemical behaviour of complexes 2 and 3: (i) Complex 2 tends to expel PPh3 upon reduction whereas complex 3 exhibits chemical reversibility and (ii) Under CO, complex 3 reacts with CO affording a new compound P, which shows a reversible wave at E1/2 ∼ −0.9 V (vs. ferrocenium/ferrocene couple). The presence of CO assists the formation of 1 after electrochemically induced loss of PPh3 during the voltammetric experiment of 2. Using DFT calculations we provide an explanation for the difference in stabilities between the Fe–PPh3 and Fe–P(OEt)3 bonds

Silicon-Heteroaromatic [FeFe] Hydrogenase Model Complexes: Insight into Protonation, Electrochemical Properties, and Molecular Structures

International audienceTo learn from Nature how to create an efficient hydrogen-producing catalyst, much attention has been paid to the investigation of structural and functional biomimics of the active site of [FeFe]-hydrogenase. To understand their catalytic activities, the μ-S atoms of the dithiolate bridge have been considered as possible basic sites during the catalytic processes. For this reason, a series of [FeFe]-H2ase mimics have been synthesized and characterized. Different [FeFe]-hydrogenase model complexes containing bulky Si–heteroaromatic systems or fluorene directly attached to the dithiolate moiety as well as their mono-PPh3-substituted derivatives have been prepared and investigated in detail by spectroscopic, electrochemical, X-ray diffraction, and computational methods. The assembly of the herein reported series of complexes shows that the μ-S atoms can be a favored basic site in the catalytic process. Small changes in the (hetero)-aromatic system of the dithiolate moiety are responsible for large differences in their structures. This was elucidated in detail by DFT calculations, which were consistent with the experimental results

Identification and evaluation of cell- growth-inhibiting bDtBPP-analogue degradation products from phosphite antioxidants used in polyolefin bioprocessing materials.

Budde D, Maier TV, Jurkiewicz E, et al. Identification and evaluation of cell- growth-inhibiting bDtBPP-analogue degradation products from phosphite antioxidants used in polyolefin bioprocessing materials. Analytical and bioanalytical chemistry. 2020;412(19):4505-4518.The inhibiting effect of the secondary phosphite antioxidant degradation product bis(2,4-di-tert-butylphenyl)phosphate (bDtBPP) on cell growth is well-known. The present study describes structurally related compounds which are likely to be formed from similar widely used phosphite antioxidants used in materials for the manufacturing of single-use (SU) equipment. Two potential candidates of such compounds-3,3',5,5'-tetra-tert-butyl-2,2'-dihydroxybiphenylphosphate (TtBBP) and bis(p-nonylphenyl)phosphate (bNPP)-were identified by chromatography and mass spectrometry followed by synthesis and X-ray structure elucidation. Additionally, the formation of TtBBP was confirmed in an analytical degradation study and its migration from SU bioprocessing material was estimated. The cytotoxicity evaluation by means of cell culture spiking experiments and flow cytometry analysis revealed that' even if cell growth was inhibited by all the compounds to some extent, bDtBPP showed the most severe effect and stoods out from the other two degradants investigated. Graphical abstract