نتایج جستجو برای: crown ether addition

تعداد نتایج: 750363  

2015
Gert Kollenz Ralf Smounig Ferdinand Belaj David Kvaskoff Curt Wentrup

The structures of two derivatives of the bisdioxine diisocyanate 1, the bisurea 4 and the biscarbamate 5, are established by X-ray crystallography and DFT calculations. These compounds possess endo,endo structures, in the case of the bisurea 4 with two nearly parallel pendant chains. The X-ray structures are reproduced very well by DFT calculations. Similar endo,endo conformations are calculate...

2012
Jie Xu Min-Min Zhao

In the title compound, C(6)H(7)ClN(+)·BF(4) (-)·C(12)H(24)O(6), the complete cation is generated by crystallographic mirror symmetry, with two C atoms and the N and Cl atoms lying on the mirror plane. The complete crown ether is also generated by mirror symmetry, as is the anion (in which the B and two F atoms lie on the mirror plane). The -NH(3) (+) group of the cation inserts into the crown-e...

Journal: :Molecules 2008
Takashi Yamanoi Yoshiki Oda Hitomi Muraishi Sho Matsuda

This paper describes a synthetic approach to a novel D-glucose-conjugated 15-crown-5 ether having a spiroketal structure starting from a 1-C-vinylated glucose derivative. The approach consists of the glycosylation of the vinylated glucose derivative to give an ethyleneoxy spacer derivative using bismuth(III) triflate, the conversion of the 1-C-vinyl group of the glucoside produced into a carbox...

Journal: :Inorganic chemistry 2005
Sherri A McFarland Douglas Magde Nathaniel S Finney

Tris(bipyridyl)ruthenium(II) complexes modified such that one of the bipyridines is appended with a crown ether display luminescence that is responsive to complexation with metal ions. The parent species, Ru(bpy)3(2+), is moderately luminescent, with an emission lifetime of about 1 micros in fluid solution at room temperature. The modified complexes are much less emissive, with lifetimes near 1...

2010
Ilia A. Guzei Lara C. Spencer Lingyun Xiao Ronald R. Burnette

In the title compound, [Li(C(8)H(16)O(4))(CD(3)CN)]ClO(4), the Li atom is penta-coordinate. The O atoms of the 12-crown-4 ether form the basal plane, whereas the N atom of the trideutero-aceto-nitrile occupies the apical position. The Li(+) atom is displaced by 0.794 (6) Å toward the apical position from the plane formed by the O atoms because the Li(+) atom is too large to fit in the cavity of...

2008
B. Ravindran Durai Nayagam Samuel Robinson Jebas J. Jebaraj Devadasan Dieter Schollmeyer

In the title compound, 2C(15)H(17)NOS·C(12)H(24)O(6), the asymmetric unit consists of one N-oxide derivative and one-half of the 18-crown-6 ether, which lies on an inversion centre. In the crown ether, the O-C-C-O torsion angles indicate a gauche conformation of the ethyl-eneoxy units, while the C-O-C-C torsion angles indicate planarity of these segments. In the N-oxide unit, the dihedral angle...

2013
Antje Albert

Z. Naturforsch. 52 b, 615-619 (1997); received January 15, 1997 Crown Ether, Crystal Structure, Hydrate, Hydrogen Bonding, Melting Diagram The melting diagram of the system 18-crown-6/water has been set up and the existence of four binary hydrates confirmed. Crystal structures have been determined for three of these, in addition to that for the hexahydrate already published. The hydrates are mo...

Journal: :Dalton transactions 2017
Feng Gao Feng-Lei Yang Xiaowan Feng Huimin Xu Wang Sun Huan Liu Xiu-Ling Li

Four half-sandwich type mononuclear lanthanide crown ether complexes with the formula [Ln(12-crown-4)(NO3)3] (Ln3+ = Dy3+ (1), Tb3+ (2), Ho3+ (3), and Er3+ (4); 12-crown-4 = 1,4,7,10-tetraoxacyclododecane) were successfully synthesized and structurally characterized. Ac magnetic susceptibility measurements reveal that dysprosium complex 1 behaves as a typical single-ion magnet, while solid stat...

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