Crystal structures of complexes of tri-, tetra-, or nonaethyleneglycol dimethyl ether with dichloropicric acid and water


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Abstract

The 1:2:2 triglyme/dichloropicric acid/water adduct is triclinic, space group P1; at 172(2) K, a = 4.9210(10), b = 13.424(3), c = 14.068(3) Å, α = 115.04(3), β = 90.93(3), γ = 92.24(3)°, Dx = 1.600(5) g cm−3, V = 840.8(3) Å3, and Z = 1. Each water molecule is hydrogen bonded to a terminal OCH3 group of one polyether and to an oxygen adjacent to an OCH3 of a neighboring polyether, resulting in two-dimensional ribbons. These ribbons, in turn, are assembled into a three-dimensional structure held together by chains of dichloropicric acid molecules connected to each other through chlorine–nitro group oxygen intermolecular interactions. The picric acid chains are attached to the water–polyether ribbons by hydrogen bonds from the picric acid to the water. The 1:2:2 tetraglyme/dichloropicric acid/water adduct is monoclinic, space group C2/c; at 172(2) K, a = 30.529(6), b = 5.4210(11), c = 25.413(5) Å, β = 122.33(3)°, Dx = 1.597(3) g cm−3, V = 3553.7(12) Å3, and Z = 4. The hydrogen bonding pattern resembles that of the analogous 1:2:2 pentaglyme complex reported previously, with the exception that both of the lone pairs of the central oxygen atom participate in hydrogen bonding to protons of water molecules. The second water proton is hydrogen bonded to a terminal OCH3 group. In this complex the dichloropicric acid molecules form a two-dimensional layer through chlorine–nitro group oxygen intermolecular interactions. The water molecules bond each isolated polyether molecule to adjacent dichloropicric acid layers. The 1:4:4 nonaglyme/dichloropicric acid/water complex is triclinic, space group P1; at 172(2) K, a = 8.0830(16), b = 13.570(3), c = 16.751(3) Å, α = 102.01(3), β = 102.39(3), γ = 96.43(3), Dx = 1.637(6) g cm−3, V = 1731.5(6), and Z = 1. The hydrogen bonding pattern is similar to that in the pentaglyme complex, except that four dichloropicric acid molecules and four water molecules are coordinated to a single polyether, and the polyether chain is appreciably disordered. In this case there are again chains of dichloropicric acid molecules held together by intermolecular chlorine–oxygen interactions. The chains are packed into two-dimensional layers held together through hydrogen bonds to water. Each isolated polyether is connected to four water molecules, two attached to dichloropicric acid molecules in one layer and the other two connected to the adjacent layer.

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