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991.
Summary The Ni2(NCS)4(4-Methylpyridine)6 complex has been prepared crystalline from methanolic solutions of Ni(NCS)2(4-Methylpyridine)4. Three dimensional x-ray diffraction data were collected by means of an automated single crystal diffractometer. The structure was solved by Patterson methods and refined to a final R value of 0.075, based on 2422 observed_ reflections. The compound crystallizes in space group P1 with one dimeric molecule in a unit cell of dimensions a = 10.57(1), 6 = 14.06(1), c = 8.66(1) Å, = 105.2(1), = 114.8(1), y = 95.6(1)°. The Ni atoms have distorted octahedral coordination with one sulfur and five nitrogen atoms - two of the four thiocyanate groups form a double bridge between the neighbouring Ni atoms.4-MePy = 4-Methylpyridine 相似文献
992.
Berger Peter Gröchenig Karlheinz Matz Gerald 《Journal of Fourier Analysis and Applications》2019,25(3):1080-1112
Journal of Fourier Analysis and Applications - We study reconstruction operators on a Hilbert space that are exact on a given reconstruction subspace. Among those the reconstruction operator... 相似文献
993.
Janusz Januszewski 《Discrete and Computational Geometry》2010,43(1):167-178
The minimum density of a covering of the plane with translates of a triangle is frac32frac{3}{2} . 相似文献
994.
Weil Representations of Symplectic Groups Over Rings 总被引:1,自引:0,他引:1
Cliff Gerald; McNeilly David; Szechtman Fernando 《Journal London Mathematical Society》2000,62(2):423-436
We are interested in Weil representations of Sp(2n, R), whereR is the ring Z/plZ, p is an odd prime and l is a positive integer,or, more generally, R = O/pl, where O is the ring of integersof a local field, p is the maximal ideal of O and O/p has oddcharacteristic. One reason for this interest is that a continuousfinite-dimensional complex representation of Sp(2n, O) has tofactor through a representation of Sp(2n, O/pl) for some l. 相似文献
995.
Janusz Matkowski 《Journal of Mathematical Analysis and Applications》2011,384(2):431-438
The problem of invariant curves for continuous mean-type mappings is considered. The obtained results are applied in solving some functional equations. 相似文献
996.
Given a class of mappings f between continua, near- stands for the class of uniform limits of sequences of mappings from . Let 2f and C(f) mean the induced mappings between hyperspaces. Relations are studied between the conditions: f near-, 2f near- and C(f) near-. A special attention is paid to the classes of open and of monotone mappings. 相似文献
997.
Semigroup Forum - For an arbitrary set X and an equivalence relation $$mu$$ on X, denote by $$P_mu (X)$$ the semigroup of partial transformations $$alpha$$ on X such that $$xmu subseteq x(ker... 相似文献
998.
Stereochemical Behavior of Pairs of P-stereogenic Phosphanyl Groups at the Dimethylxanthene Backbone
Dr. Karel Škoch Dr. Constantin G. Daniliuc Marcel Müller Prof. Dr. Stefan Grimme Dr. Gerald Kehr Prof. Dr. Gerhard Erker 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(20):e202200248
The P-stereogenic bis(phosphanes) 7 and 9 , featuring pairs of P(Mes)-ethynyl or vinyl substituents at the dimethyl xanthene backbone show rather low barriers of stereochemical inversion at phosphorus. π-Conjugative effects are probably causing these low inversion barriers. Compound 7 reacted with B(C6F5)3 to form the nine-membered heterocyclic product 10 , featuring a [P]−C≡C−B(C6F5)3 substituent. Compound 7 was converted to the bis[P(Mes)vinyl] xanthene derivative 9 , which gave the zwitterionic P(H)(Mes)−CH=CH−B(C6F5)3 containing product 16 upon treatment with B(C6F5)3. Thermally induced epimerization barriers at phosphorus of ca. 20 to 27 kcal mol−1 were calculated by DFT for the alkenyl- and alkynyl-P derived systems 6 to 9 , 15 and 16 and experimentally determined for the examples 7 and 16 . 相似文献
999.
Krzesimir Korona Michał Terlecki Dr. Iwona Justyniak Michał Magott Dr. Jan Żukrowski Dr. Arkadiusz Kornowicz Prof. Dawid Pinkowicz Prof. Adam Kubas Prof. Janusz Lewiński 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(40):e202200620
Paddlewheel-type binuclear complexes featuring metal−metal bonding have been the subject of widespread interest due to fundamental concern in their electronic structures and potential applications. Here, we explore the molecular and electronic structures of diiron(II,II) complexes with N,N’-diarylformamidinate ligands. While a paddlewheel-type diiron(II,II) complex with N,N’-diphenylformamidinate ligands (DPhF) exhibits the centrosymmetric [Fe2(μ-DPhF)4] structure, a minor alteration in the ligand system, i. e., switching from phenyl to p-tolyl N-substituted formamidinate ligand (DTolF), resulted in the isolation of an unprecedented non-centrosymmetric [Fe(μ-DTolF)3Fe(κ2-DTolF)] complex. Both complexes were characterized using single-crystal X-ray diffraction, magnetic measurements, 57Fe Mössbauer spectroscopy, and cyclic voltammetry along with high-level ab-initio calculations. The results provide a new view on a range of factors controlling the ground-state electronic configuration and structural diversity of homoleptic diiron(II,II) complexes. Model calculations determined that the Mayer bond orders for Fe−Fe interactions are significantly lower than 1 and equal to 0.15 and 0.28 for [Fe2(μ-DPhF)4] and [Fe(μ-DTolF)3Fe(κ2-DTolF)], respectively. 相似文献
1000.
Periodica Mathematica Hungarica - Any sequence of d-dimensional boxes of edge length smaller than or equal to 1 with total volume not greater than $$(3-2sqrt{2})cdot 3^{-d}$$ can be packed online... 相似文献