Crystal structure of 4,4,5,5-tetramethylimidazoline-2-yl-(2’-chloro- 5′-nitrophenyl)-1-hydroxide-bis(hexafluoroacetyl acetonato)-zinc(II), Zn[C3HO2(CF3)2]2(C13H15ClN3O3)

C23H17ClF12N3O7Zn, triclinic, P1 (no. 2), a = 10.1626(9) A, b = 10.917(1) A, c = 16.157(2) A, 0 = 76.978(2)°, 1 = 77.780(1)°, " = 66.711(1)°, V = 1589.0 A, Z = 2, Rgt(F) = 0.071, wRref(F) = 0.237, T = 291 K. Source of material 4,4,5,5-tetramethylimidazoline-2-yl-(2+-chloro-5+-nitrophenyl)1-hydroxide) (IM-mNO2) was synthesized using a method in the literature [1]. The complex Zn(IM-mNO2)(hfac)2 (hfac = hexafluoroacetyl acetonate) was synthesized by adding Zn(hfac)2 (1 mmol) in boiling n-heptane (25 mL), and the solution was left to boil for 30 min and then cooled down to 65 °C, 1 mmol of the crystalline solid radicalwas slowly addedwhilst stirring followed by 5 ml of CH2Cl2. The solution was allowed to stand at room temperature for several days to give brown needle-like crystals. Experimental details The large R values are caused by the low quality of the crystals probably connected with the disorder (figure, bottom). Discussion New approaches in the design of novel molecular magneticmaterials have been the focus of active investigation during the past decades [2]. The popular family concerns the nitronyl nitroxide radicals since they are stable and easy to functionalize [3].M(hfac)2 is widely used in the synthesis of molecular magnets (M = transition metal) and the synthesis of molecule-based magnetic materials is one of the major subjects of materials science [4-7].The synthesis of new molecular magnetic materials that combine transition metal ions and pure organic radicals as ligating sites have attracted much more attention in the last few years [8-10]. In the title complex, the Zn(hfac)2with the IM-mNO2 ligand forms a distorted trigonal bipyramidwithN atom of the imidazoline unit, O4 andO6 in the basal plane,while the axial positions are occupied byO5 andO7 (figure, top).The Zn(II) atom lies 0.049A above the base plane, nearly coplanar with O4, O6 and N2, and a Zn1—N2 bond length of 2.046(5)A.TheN—O bond distance is 1.278(8)A, which is in the normal range for nitroxides being from 1.25 A to 1.32A [11,12]. The Zn—O (Zn1—O7, Zn1—O5) bond lengths in axial direction are 2.087(4) A and 2.063(4) A, respectively. Both are longer than those of the equatorial Zn—O (d(Zn1—O4) = 1.994(4) A, d(Zn1—O6) = 1.984(4) A). The bond length of Zn1—N2with 2.046(5)A is in a normal range [12].The angles of O6–Zn1–O4 (114.5(2)°), O6–Zn1–N2 (125.0(2)°), O4–Zn1–N2 (120.5(2)°) are approximately 120°, while theO5–Zn1–O7 angle is 179.5(2)°. The nitronyl nitroxide unit (imidazoline ring) is not coplanar with the phenyl ring to which the nitronyl nitroxide unit is directly linked, forming a dihedral angle of 73.16°. Z. Kristallogr. NCS 222 (2007) 181-183 / DOI 10.1524/ncrs.2007.0075 181 © by Oldenbourg Wissenschaftsverlag, Munchen