850 research outputs found
{μ-6,6′-Dimethoxy-2,2′-[propane-1,3-diylbis(nitrilomethylidyne)]diphenolato}trinitratocopper(II)europium(III)
In the title complex, [CuEu(C19H20N2O4)(NO3)3], the CuII ion is four-coordinated in a square-planar geometry by two O atoms and two N atoms of the deprotonated Schiff base. The EuIII atom is ten-coordinate, chelated by three nitrate groups and linked to the four O atoms of the deprotonated Schiff base
A second orthorhombic polymorph of 2-(pyridin-4-ylmethoxy)phenol
The crystal structure of the title compound, C12H11NO2, represents a new orthorhombic polymorph II of the previously reported orthorhombic form I [Zhang et al. (2009 ▶) Acta Cryst. E65, o3160]. In polymorph II, the six-membered rings form a dihedral angle of 13.8 (1)° [71.6 (1)° in I], and O—H⋯N hydrogen bonds link molecules into chains along [100], whereas the crystal structure of I features hydrogen-bonded centrosymmetric dimers
{μ-6,6′-Dimethoxy-2,2′-[propane-1,3-diylbis(nitrilomethylidyne)]diphenolato}trinitratocopper(II)samarium(III) acetone solvate
In the title complex, [CuSm(C19H20N2O4)(NO3)3]·CH3CO-CH3, the CuII atom is four-coordinated in a square-planar geometry by two O atoms and two N atoms of the deprotonated Schiff base. The SmIII atom is ten-coordinate, chelated by three nitrate groups and linked to the four O atoms of the deprotonated Schiff base
catena-Poly[[bis(nitrato-κ2 O,O′)cobalt(II)]-μ-4,4′-bis(pyrazol-1-ylmethyl)biphenyl-κ2 N 2:N 2′]
In the title compound, [Co(NO3)2(C20H18N4)]n, the CoII atom lies on a crystallographic twofold axis and the coordination geometry can be considered as a slightly distorted tetrahedron defined by two O atoms from two nitrate groups and two N atoms from two ligand molecules. A distorted octahedron may be assumed when two of the symmetry-related nitrate O atoms with Co—O distances of 2.3449 (19) Å are added to the coordination environment. Another twofold axis, passing through the middle of the biphenyl bonds, is observed in the crystal structure. A chain is built up by the ligands linking the CoII ions along [101]
Containment Control of Multi-Agent Systems with Dynamic Leaders Based on a -Type Approach
This paper studies the containment control problem of multi-agent systems
with multiple dynamic leaders in both the discrete-time domain and the
continuous-time domain. The leaders' motions are described by -order
polynomial trajectories. This setting makes practical sense because given some
critical points, the leaders' trajectories are usually planned by the
polynomial interpolations. In order to drive all followers into the convex hull
spanned by the leaders, a -type ( and are short for {\it
Proportion} and {\it Integration}, respectively; implies that the
algorithm includes high-order integral terms) containment algorithm is
proposed. It is theoretically proved that the -type containment algorithm
is able to solve the containment problem of multi-agent systems where the
followers are described by any order integral dynamics. Compared with the
previous results on the multi-agent systems with dynamic leaders, the
distinguished features of this paper are that: (1) the containment problem is
studied not only in the continuous-time domain but also in the discrete-time
domain while most existing results only work in the continuous-time domain; (2)
to deal with the leaders with the -order polynomial trajectories,
existing results require the follower's dynamics to be -order integral while
the followers considered in this paper can be described by any-order integral;
and (3) the "sign" function is not employed in the proposed algorithm, which
avoids the chattering phenomenon. Furthermore, in order to illustrate the
practical value of the proposed approach, an application, the containment
control of multiple mobile robots is studied. Finally, two simulation examples
are given to demonstrate the effectiveness of the proposed algorithm
(E)-3-(9-Anthryl)-1-(4-fluorophenyl)-2-(4-nitro-1H-imidazol-1-yl)prop-2-en-1-one
In the title compound, C26H16FN3O3, the dihedral angle between the anthryl and fluorophenyl groups is 37.8 (1)°. With respect to the imidazolyl group, the twist angles between the imidazolyl group and the anthryl unit and between the imidazoly group and the fluorophenyl group are 64.4 (1) and 74.5 (1)°, respectively
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