Mixed transition metal/lanthanide complexes: structural characterization of solids containing cage amine chromium(III) cations and tris(dipicolinato)lanthanide anions

As the foundation to a survey of interactions between chromium(III) and lanthanide(III) ions within the same crystal lattice, a series of complexes of stoichiometry [Cr((NH2)(2)sar)]-[Ln(dipic)(3)].8H(2)O (sar = 3,6,10,13,16,19-hexaazabicyclo[6.6.6]icosane, Ln = La-Lu plus Y, dipic = pyridine-2,6-dicarboxylate) has been synthesized and structurally characterized by room-temperature single-crystal X-ray studies. An isomorphous series is found for all Ln, being triclinic, P (1) over bar, a approximate to 18 . 1, b approximate to 13 . 3, c approximate to 11 Angstrom, alpha approximate to 111 . 5, beta approximate to 96 . 2 gamma approximate to 109 . 2 degrees, Z = 2 formula units, full structure determinations being recorded for Ln = La (conventional R 0 . 048 on \F\ for N-o 6494 independent 'observed' [I > 3 sigma(I)] reflections at convergence), Ce (R 0 . 036 for N-o 8980) and Lu (R 0 . 046 for N-o 6791). A less well defined protonated series, with a 2:3 Cr/Ln ratio, has also been characterized specifically for Ln = La [orthorhombic, Pbca, a 26 . 223(8), b 53 . 17(3), c 18 . 329(9) Angstrom, Z = 8; R 0 . 092 for N-o 5104], the lutetium analogue having a similar cell.