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881.
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DRAB David M. SHAMSHINA Julia L. SMIGLAK Marcin COJOCARU O. Andreea KELLEY Steven P. ROGERS Robin D. 《中国科学:化学(英文版)》2012,55(8):1620-1626
Zinc halide-complexed alkyl-bridged bi-heterocycles were obtained as zwitterions from the Click reaction of a series of N-cyanoalkyl-N-alkylimidazolium halide ionic liquids with sodium azide. Reaction optimization showed fast reaction times and milder conditions compared to conventional Click syntheses from neutral nitriles. 相似文献
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Nitration of Norcorrolatonickel(II): First Observation of a Diatropic Current in a System Comprising a Norcorrole Ring 下载免费PDF全文
Zhihong Deng Prof. Xiaofang Li Prof. Marcin Stępień Prof. Piotr J. Chmielewski 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(12):4231-4246
A one‐pot reaction of 5,14‐bis(mesityl)‐norcorrolatonickel(II) with isoamyl nitrite under mild reaction conditions resulted in the consecutive formation of 3‐nitro‐, 3,12‐dinitro‐ and 3,16‐dinitro‐, 3,7,12‐trinitro‐, and 3,7,12,16‐tetranitro‐norcorrolatonickel(II) in 50–80 % yield. The substituted macrocycles retained their antiaromatic character. The observed regioselectivity of the substitution was analyzed by comparing the relative energies of the DFT energy‐optimized models of the radical or arenium cationic intermediates that can be formed upon reaction with NO2. The nitrated systems were characterized by high‐resolution mass spectrometry, NMR and UV/Vis spectroscopy, X‐ray diffraction analysis, cyclic voltammetry, and DFT calculations. A significant and systematic cathodic shift of the redox couples was observed to correlate with an increasing number of the NO2 group. A decrease of the LUMO energies in the tri‐ and tetra‐nitrated products stabilizes mono‐ and bis‐reduced complexes of these ligands. The reduction takes place on the macrocycle rather than on the metal ion leading to the consecutive formation of stable paramagnetic monoanion radicals and water‐soluble diamagnetic dianions with an aromatic character, which were revealed by ESR and 1H NMR measurements, respectively. The electronic structures of the reduced forms were analyzed by extensive TD‐DFT calculations. 相似文献
884.
Marcin A. Majewski Yongseok Hong Prof. Tadeusz Lis Dr. Janusz Gregoliński Prof. Piotr J. Chmielewski Dr. Joanna Cybińska Prof. Dongho Kim Prof. Marcin Stępień 《Angewandte Chemie (International ed. in English)》2016,55(45):14072-14076
Octulene, the higher homologue of kekulene and septulene, was synthesized using the fold‐in method. This new hydrocarbon macrocycle contains a large 24‐membered inner circuit, which is peripherally fused to 24 benzene rings. Such an arrangement produces considerable hyperbolic distortion of the π‐conjugated surface. The consequences of distortion in octulene were explored using photophysical methods, which revealed a reduced electronic band gap and greater flexibility of the π system. Octulene contains a functional cavity with a diameter larger than 5.5 Å that is capable of efficiently binding the chloride anion in a nonpolar solvent (Ka= 2.2(4)×104 m ?1, 1 % dichloromethane (DCM) in benzene). The octulene–chloride interaction is stabilized by eight weak C(sp2)H???Cl bonds, providing the first example of a hydrocarbon‐based anion receptor. 相似文献
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Aleksandra Marciniak Justyna Brasuń 《Journal of Radioanalytical and Nuclear Chemistry》2017,313(2):279-289
Peptide receptor radionuclide therapy (PRRT) is a promising way to treat patients with inoperable tumors or metastatic neuroendocrine tumors. This therapeutic strategy is using radiolabeled peptides, which are capable of selective biding to receptors overexpressed in the cancer cells. One of the group of receptor-avid peptide used in the PRRT are the analogues of somatostatin (SST) connected to the complexes of radionuclides (e.g. 90Y, 177Lu or 111In). Many studies have shown that radiopharmaceuticals based on Cu radioisotopes are promising for the diagnosis and treatment of various cancers. This mini-review focuses on recent developments and summarises the results of multiple studies addressing SST agonists and antagonists radiolabeled to Cu radioisotopes. 相似文献
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Gierczyk B Zalas M Kaźmierczak M Grajewski J Pankiewicz R Wyrzykiewicz B 《Magnetic resonance in chemistry : MRC》2011,49(10):648-654
Three series of substituted 1,3,4-oxadiazoles were studied by (17)O NMR spectroscopy. Chemical shifts values were correlated with empirical Hammett parameters as well as calculated bond lengths and chemical shielding values. 相似文献