SYNTHESES AND STRUCTURES OF MANGANESE(II) AND MANGANESE(III) NITRATE DIAMINOSARCOPHAGINE COMPLEXES

The syntheses of [Mn((NH3)2Sar)] (NO3)4.H2O and [Mn((NH3)2sar)] (NO3)5.2H2O, manganese(II) and manganese(III) complexes of the cage amine ligand diaminosarcophagine (diaminosarcophagine = (NH2)2sar = 1,8-diamino-3,6,10,13,16,19-hexaazabicyclo[6.6.6]icosane) in its diprotonated form are recorded, together with their single-crystal X-ray structure determinations at c. 295 K. The monoclinic P2(1) array of the manganese(II) complex (a 12.386(5), b 12.431(4), c 8.598(4) angstrom, beta 93.89(4)-degrees, V 1321(1) angstrom3, Z 2) is archetypical for similar complexes of a wide variety of transition metals; for the present determination, R was 0.027 for 2013 'observed' (I > 3sigma(I)) reflections. The manganese(iii) complex is monoclinic C2/c, a 10.744(2), b 13.294(4), c 20.462(9) angstrom, beta 102.38(3)-degrees, Z 4; R was 0-055 for 1629 'observed' reflections. Both structures show the six secondary nitrogen atoms of the ligand to be bound to the manganese ion in a configuration approximately halfway between a trigonal prism and an octahedron. The ligand is in the lel3 conformation. In the first complex, Mn-N distances, appropriate to high-spin manganese(ii), range from 2.228(3) to 2.253(3) angstrom, mean 2.23(8) angstrom; in the second, surprisingly, the distances are even more closely ranged (unlike those of the sarcophagine analogue of the previous paper), 2.115(4)-2.127(4) angstrom, the mean (2.12(2) angstrom) being closely comparable to that recorded for the sar analogue, and show no appreciable variation attributable to the expected Jahn-Teller effect.