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161.
Superchiral Pd3L6 Coordination Complex and Its Reversible Structural Conversion into Pd3L3Cl6 Metallocycles 下载免费PDF全文
Dr. Ondřej Jurček Pia Bonakdarzadeh Dr. Elina Kalenius Dr. Juha Matti Linnanto Dr. Michael Groessl Dr. Richard Knochenmuss Prof. Janne A. Ihalainen Prof. Kari Rissanen 《Angewandte Chemie (International ed. in English)》2015,54(51):15462-15467
Large, non‐symmetrical, inherently chiral bispyridyl ligand L derived from natural ursodeoxycholic bile acid was used for square–planar coordination of tetravalent PdII, yielding the cationic single enantiomer of superchiral coordination complex 1 Pd3 L 6 containing 60 well‐defined chiral centers in its flower‐like structure. Complex 1 can readily be transformed by addition of chloride into a smaller enantiomerically pure cyclic trimer 2 Pd3 L 3Cl6 containing 30 chiral centers. This transformation is reversible and can be restored by the addition of silver cations. Furthermore, a mixture of two constitutional isomers of trimer, 2 and 2′ , and dimer, 3 and 3′ , can be obtained directly from L by its coordination to trans‐ or cis‐N‐pyridyl‐coordinating PdII. These intriguing, water‐resistant, stable supramolecular assemblies have been thoroughly described by 1H DOSY NMR, mass spectrometry, circular dichroism, molecular modelling, and drift tube ion‐mobility mass spectrometry. 相似文献
162.
Hannu Nykänen Promise A. Mpamah Antti J. Rissanen 《Isotopes in environmental and health studies》2013,49(6):622-641
ABSTRACTWe studied natural and forestry-drained peatlands to examine the effect of over 34 years lowered water table on the δ13C values of vegetation, bulk peat and subsoil. In the seven studied sites, δ13C in the basal peat layer was 1.1 and 1.2?‰ lower than that of the middle-layer and surface layer, respectively. Furthermore, there was a positive correlation between the δ13C values of the basal and surface peat layers, possibly due to carbon (C) recycling within the peat column. In the same mire complex, natural fen peat δ13C values were lower than those of the nearby bog, possibly due to the dominance of vascular plants on fen and the generally larger share of recycled C in the fens than in the bogs. Furthermore, natural and 51 years previously drained fen and bog, on the opposite sides of a ditch on the same mire complex, showed no significant differences in δ13C values. Plant δ13C values were lower, while δ13C values of subsoil were higher in the drained than in the natural site of the fen. 相似文献
163.
S. Rahaman V.-V. ElomaaT. Eronen J. HakalaA. Jokinen A. KankainenJ. Rissanen J. SuhonenC. Weber J. Äystö 《Physics letters. [Part B]》2011,703(4):412-416
The Q values of the 116Cd and 130Te double-beta decaying nuclei were determined by using a Penning trap mass spectrometer. The new atomic mass difference between 116Cd and 116Sn of 2813.50(13) keV differs by 4.5 keV and is 30 times more precise than the previous value of 2809(4) keV. The new value for 130Te, 2526.97(23) keV is close to the Canadian Penning trap value of 2527.01 ± 0.32 keV (Scielzo et al., 2009) [1], but differs from the Florida State University trap value of 2527.518 ± 0.013 keV (Redshaw et al., 2009) [2] by 0.55 keV (2σ). These values are sufficiently precise for ongoing neutrinoless double-beta decay searches in 116Cd and 130Te. Hence, our Q values were used to compute accurate phase-space integrals for these double-beta decay nuclei. In addition, experimental two-neutrino double-beta decay nuclear matrix elements were determined and compared with the theoretical values. The neutrinoless double-beta decay half-lives for these nuclei were estimated using our precise phase-space integrals and considering the range of the best available matrix elements values. 相似文献
164.
Kalenius E Beyeh NK Jänis J Rissanen K 《Chemical communications (Cambridge, England)》2011,47(9):2649-2651
Pyrogallarene shows concentration-dependent instability in dilute solutions resulting in elimination of two ketene molecules and formation of pyrogallarene lactones. This unexpected phenomenon, which is not observed with resorcinarenes, highlights the significance of the four hydroxyl groups at 2-position for the molecular characteristics of pyrogallarenes. 相似文献
165.
Taesch J Heitz V Topić F Rissanen K 《Chemical communications (Cambridge, England)》2012,48(42):5118-5120
A large covalent cage incorporating two porphyrins attached by four long and flexible polyether chains each bearing two 3-pyridyl ligands was synthesized from a DABCO-templated olefin metathesis reaction. The X-ray structure of the cage with the DABCO coordinated inside the cavity to the two zinc(II) porphyrins reveals a highly symmetric structure. 相似文献
166.
Jorma Roine Matti Murtomaa Markko Myllys Jarno Salonen 《Journal of Electrostatics》2012,70(5):428-437
The feasibility of electroencapsulation of mesoporous silicon (PSi) micro- and nanoparticles as a method to seal the PSi particles in mechanically processable solid units, and to facilitate time and site specific drug release from the pores of PSi particles, is of interest in the present work. Suitable microcapsules and micromatrix particles were produced in a single-step process using a setup with two electrospraying nozzles kept at high electric potentials of opposite polarities. The structures of the produced particles were analyzed by microscope and X-ray micro- and nanotomography imaging, and optimization of the electroencapsulation process production efficiency is discussed. 相似文献
167.
Algora A Jordan D Taín JL Rubio B Agramunt J Perez-Cerdan AB Molina F Caballero L Nácher E Krasznahorkay A Hunyadi MD Gulyás J Vitéz A Csatlós M Csige L Aysto J Penttilä H Moore ID Eronen T Jokinen A Nieminen A Hakala J Karvonen P Kankainen A Saastamoinen A Rissanen J Kessler T Weber C Ronkainen J Rahaman S Elomaa V Rinta-Antila S Hager U Sonoda T Burkard K Hüller W Batist L Gelletly W Nichols AL Yoshida T Sonzogni AA Peräjärvi K 《Physical review letters》2010,105(20):202501
The β feeding probability of (102,104,105,106,107)Tc, 105Mo, and 101Nb nuclei, which are important contributors to the decay heat in nuclear reactors, has been measured using the total absorption technique. We have coupled for the first time a total absorption spectrometer to a Penning trap in order to obtain sources of very high isobaric purity. Our results solve a significant part of a long-standing discrepancy in the γ component of the decay heat for 239Pu in the 4-3000 s range. 相似文献
168.
A 2,6‐dibutoxylnaphthalene‐based tetralactam macrocycle was designed and synthesized. This macrocycle shows highly selective recognition to phenazine – a well‐known secondary metabolite in bacteria and an emerging disinfection byproduct in drinking water. In contrast, the macrocycle shows no binding to the structurally similar dibenzo‐1,4‐dioxin. It was revealed that hydrogen bonding, π‐π and σ‐π interactions are the major driving forces between phenazine and the new tetralactam macrocycle. A perfect complementarity in electrostatic potential surfaces may explain the high selectivity. In addition, the macrocycle shows fluorescent response to phenazine, demonstrating its potential in fluorescent detection of phenazine. 相似文献
169.
Hakala J Rahaman S Elomaa VV Eronen T Hager U Jokinen A Kankainen A Moore ID Penttilä H Rinta-Antila S Rissanen J Saastamoinen A Sonoda T Weber C Aystö J 《Physical review letters》2008,101(5):052502
Atomic masses of the neutron-rich isotopes (76-80)Zn, (78-83)Ga, (80-85)Ge, (81-87)As, and (84-89)Se have been measured with high precision using the Penning trap mass spectrometer JYFLTRAP at the IGISOL facility. The masses of (82,83)Ga, (83-85)Ge, (84-87)As, and 89Se were measured for the first time. These new data represent a major improvement in the knowledge of the masses in this neutron-rich region. Two-neutron separation energies provide evidence for the reduction of the N=50 shell gap energy towards germanium (Z=32) and a subsequent increase at gallium (Z=31). The data are compared with a number of theoretical models. An indication of the persistent rigidity of the shell gap towards nickel (Z=28) is obtained. 相似文献
170.
Eronen T Elomaa VV Hager U Hakala J Hardy JC Jokinen A Kankainen A Moore ID Penttilä H Rahaman S Rinta-Antila S Rissanen J Saastamoinen A Sonoda T Weber C Aystö J 《Physical review letters》2008,100(13):132502
Using a new fast cleaning procedure to prepare isomerically pure ion samples, we have measured the beta-decay Q(EC) values of the superallowed beta emitters 5(0)Mn and (54)Co to be 7634.48(7) and 8244.54(10) keV, respectively, results which differ significantly from the previously accepted values. The corrected Ft values derived from our results strongly support new isospin-symmetry-breaking corrections that lead to a higher value of the up-down quark mixing element V(ud) and improved confirmation of the unitarity of the Cabibbo-Kobayashi-Maskawa matrix. 相似文献