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991.
Lin Li Tony Stüker Prof. em. Dr. Lester Andrews Dr. habil. Helmut Beckers Prof. Dr. Sebastian Riedel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(7):1795-1805
Uranium and thorium hydrides are known as functional groups for ligand stabilized complexes and as isolated molecules under matrix isolation conditions. Here, the new molecular products of the reactions of laser-ablated U and Th atoms with HCl and with HBr, namely HUCl, HUBr and HThCl, HThBr, based on their mid and far infrared spectra in solid argon, are reported. The assignment of these species is based on the close agreement between observed and calculated vibrational frequencies. The H−U and U−35Cl stretching modes of HUCl were observed at 1404.6 and 323.8 cm−1, respectively. Using DCl instead to form DUCl gives absorption bands at 1003.1 and 314.7 cm−1. The corresponding bands of HThCl are 1483.8 (H−Th) and 1058.0 (D −Th), as well as 340.3 and 335.8 cm−1 (Th−35Cl), respectively. HUBr is observed at 1410.6 cm−1 and the BP86 computed shift from HUCl is 6.2 cm−1 in excellent agreement. The U−H stretching frequency increases from 1383.1 (HUF), 1404.6 (HUCl), 1410.6 (HUBr) to 1423.6 cm−1 (UH) as less electronic charge is removed from the U−H bond by the less electronegative substituent. These U−H stretching frequencies follow the Mayer bond orders calculated for the three HUX molecules. A similar trend is found for the Th counterparts. Additional absorptions are assigned to the H2AnX2 molecules (An=U, Th, X=Cl, Br) formed by the exothermic reaction of a second HX molecule with the above primary products. 相似文献
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Claudia Schremmer Dr. Claudia Cordes Dr. Iris Klawitter Dr. Marie Bergner Dr. Christine E. Schiewer Dr. Sebastian Dechert Dr. Serhiy Demeshko Dr. Michael John Prof. Dr. Franc Meyer 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(15):3918-3929
Starting from their six-coordinate iron(II) precursor complexes [L8RFe(MeCN)]2+, a series of iron(III) complexes of the known macrocyclic tetracarbene ligand L8H and its new octamethylated derivative L8Me, both providing four imidazol-2-yliden donors, were synthesized. Several five- and six-coordinate iron(III) complexes with different axial ligands (Cl−, OTf−, MeCN) were structurally characterized by X-ray diffraction and analyzed in detail with respect to their spin state variations, using a bouquet of spectroscopic methods (NMR, UV/Vis, EPR, and 57Fe Mößbauer). Depending on the axial ligands, either low-spin (S=1/2) or intermediate-spin (S=3/2) states were observed, whereas high-spin (S=5/2) states were inaccessible because of the extremely strong in-plane σ-donor character of the macrocyclic tetracarbene ligands. These findings are reminiscent of the spin state patterns of topologically related ferric porphyrin complexes. The ring conformations and dynamics of the macrocyclic tetracarbene ligands in their iron(II), iron(III) and μ-oxo diiron(III) complexes were also studied. 相似文献
996.
Peter Franzmann Sebastian B. Beil Dr. Dieter Schollmeyer Prof. Dr. Siegfried R. Waldvogel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(8):1936-1940
A highly efficient synthetic protocol for the synthesis of thia- and selenaheterocycles has been developed. By employing a MoCl5-mediated intramolecular dehydrogenative coupling reaction, a broad variety of structural motifs was isolated in yields up to 94 %. The electrophilic key transformation is tolerated by several labile moieties like halides and tertiary alkyl groups. Due to the use of disulfide or diselenide precursors, a high atom efficiency was achieved. 相似文献
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Timo A. Kinder René Pior Dr. Sebastian Blomeyer Beate Neumann Dr. Hans-Georg Stammler Prof. Dr. Norbert W. Mitzel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(23):5899-5903
Chlorogermane (C2F5)3GeCl with very electronegative pentafluoroethyl groups was converted with LiCH2P(tBu)2 to obtain the intramolecular frustrated Lewis pair (FLP) (C2F5)3GeCH2P(tBu)2, a neutral, germanium-based FLP. Its reactivity was compared to its silicon homologue (C2F5)3SiCH2P(tBu)2. Both FLPs cleave NO but give cyclic (Si) and open-chain oxides (Ge). In reactions with HCl both FLPs gave the same adduct type in the solid state, while the proton seems more mobile in solution in the germanium case. Reactions with PhCNO and Me3SiCHN2 result in ring-type adducts. The structures of (C2F5)3GeCH2P(tBu)2 and of five adducts with substrates were elucidated by X-ray diffraction. The study clearly showed the germanium compound to have a more moderate Lewis acidity compared to the silicon analogue. 相似文献
998.
Jemini Jose Athimotlu Raju Rajamani Sreekanth Anandaram Sujin P. Jose Sebastian C. Peter Sreeja P B 《应用有机金属化学》2019,33(9)
Covalently anchored chromium complex on reduced graphene oxide (rGO‐Cr) is successfully synthesised through trimethoxy silyl propanamine (TMSPA) and phenyl azo salicylaldehyde (PAS) coupling. The rGO‐Cr is characterised by Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), electron dispersive analysis of X‐rays (EDAX), Raman spectroscopy, scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). Absorption and emission properties of rGO‐TMSPA‐PAS are studied by excitation dependent photoluminescence emissions at room temperature. Electrochemical sensing activity of rGO‐Cr is monitored for paracetamol using modified glassy carbon electrode. Cyclic voltammetry measurements indicated that rGO‐Cr substantially enhance the eletrochemical response of paracetamol. The experimental factors are investigated and optimized. 相似文献
999.
Faßbender Sebastian Döring Ann-Katrin Meermann Björn 《Analytical and bioanalytical chemistry》2019,411(27):7261-7272
Analytical and Bioanalytical Chemistry - In the recent decade, metal pyrithione complexes have become important biocides for antifouling purposes in shipping. The analysis of metal pyrithione... 相似文献
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