Kahwa, Ishenkumba A.,; Fender, Nicolette S.; Finegan, S.; Miller, Dione; Mitchell, Maureen; Fronczek, Frank R.
Author Affiliation, Ana.
Chemistry; Faculty of Pure and Applied Sciences
Coordination characteristics of divalent, tetrahedral (Td and D2d) tetrahalometalate anions of 3d elements and solid-state 18C6 reorientation
Date of Publication
The MX42-compounds (M = 3d element, X = halogen) are good ligands for [A18C6]n+ cation (A = Rb, T1, Ba). The regular MX42- tetrahedra (Td) coordinate via the triangular faces (facial ligation), while the flattened MC142- tetrahedra (D2d) prefer edge ligation. The cryogenic structure of [(T118C6)4CuBr4][T1Br4]2 (1) confirms solid-state reorientational motion of coordinated 18C6 previously detected in some metal and metal-free host-guest crystals by variable-temperature solid-state 1H and 13C NMR (Chem. Abstr. 1989, 111, 56905b). The motions generating the reorientations are very sensative to the detailed crystal environment; dependence on crystal water and nature of the 3d element is evident. Crystal data: [(T118C6)4CuBr4][T1Br4]2 (1) cryogenic (115 K), cubic, space group F23 with a = 20.674(3) Å, V =8837(1) Å3, Z = 4, 700 reflections (I>3s(I), and R = 0.054; [(T118C6)4MnC14]-[T1C14]2 (2), cubic, space group F23 with a = 20.789(2) Å, V = 8985.2(9) Å3, Z = 4,693 reflections (I>1s(I>3s(I)), and R = 0.036; (Ba 18C6)CoC14.2H2O (3), triclinic, space group PÌ with a = 8.769(1) Å, b = 10.383(2) Å, c = 13.912(1) Å, a = 98.29(1)°, b = 89.77(1)°, g = 113.64(1)°, V = 1146.2(6) Å3, Z = 2,6156 reflections (I>3s(I)), and R = 0.033; Rb(15C5)2T1Br4 (4), orthorhombic, space group Cmcm, with a = 13.630(1) Å, b = 11.631(1) Å, c = 22.021(1) Å, V = 3491.0(7) Å3, Z = 4,847 reflections (I>1s(I)), and R = 0.054....