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Crystal Packing Of Two 5-Substituted 2-Methyl-4-Nitro-1h-Imidazoles, Pawel Wagner, Krzysztof Swierczek, Maciej Kubicki
Crystal Packing Of Two 5-Substituted 2-Methyl-4-Nitro-1h-Imidazoles, Pawel Wagner, Krzysztof Swierczek, Maciej Kubicki
Australian Institute for Innovative Materials - Papers
Infinite chains connected by N-H...N hydrogen bonding form the primary packing motif in two closely related 4-nitroimidazole derivatives, viz. 5-bromo-2-methyl-4-nitro-1H-imidazole, C4H4BrN3O2, (I), and 2-methyl-4-nitro-1H-imidazole-5-carbonitrile, C5H4N4O2, (II). These chains are almost identical, even though in (II) there are two symmetry-independent molecules in the asymmetric unit. The differences appear in the interactions between the chains; in (I), there are strong C-Br...O halogen bonds, which connect the chains into a two-dimensional grid, while in (II), the cyano group does not participate in specific interactions and the chains are only loosely connected into a three-dimensional structure.
Two Different Modes Of Halogen Bonding In Two 4-Nitroimidazole Derivatives, Maciej Kubicki, Pawel Wagner
Two Different Modes Of Halogen Bonding In Two 4-Nitroimidazole Derivatives, Maciej Kubicki, Pawel Wagner
Australian Institute for Innovative Materials - Papers
In the crystal structures of the two imidazole derivatives 5-chloro-1,2-dimethyl-4-nitro-1H-imidazole, C5H6ClN3O2, (I), and 2-chloro-1-methyl-4-nitro-1H-imidazole, C4H4ClN3O2, (II), C—Cl...O halogen bonds are the principal specific interactions responsible for the crystal packing. Two different halogen-bond modes are observed: in (I), there is one very short and directional C—Cl...O contact [Cl...O = 2.899 (1) Å], while in (II), the C—Cl group approaches two different O atoms from two different molecules, and the contacts are longer [3.285 (2) and 3.498 (2) Å] and less directional. …
Band Structures, Magnetic Properties, And Enhanced Magnetoresistance In The High Pressure Phase Of Gd And Y Doped Two-Dimensional Perovskite Sr2coo4 Compounds, Xiaolin Wang, E Takayama-Muromachi, S X. Dou, Zhenxiang Cheng
Band Structures, Magnetic Properties, And Enhanced Magnetoresistance In The High Pressure Phase Of Gd And Y Doped Two-Dimensional Perovskite Sr2coo4 Compounds, Xiaolin Wang, E Takayama-Muromachi, S X. Dou, Zhenxiang Cheng
Australian Institute for Innovative Materials - Papers
The authors present their studies on the band structures and on the magnetic and magnetotransport properties of the high pressure phase of Sr2-xRExCoO4 [rare earth (RE)=Gd and Y, x=0.1-0.5] compounds which were synthesized by a high pressure and high temperature technique. The authors found that as x increases, the magnetoresistance {(PH-P0)/p0} increases up to -17% at 5 K and 7 T, which is 2.5 times higher than that for undoped Sr2CoO4, although the ferromagnetic transition drops from 255 to 200 K for the Gd doping with x=0.3. …