Template synthesis of the sixteen-membered, potentially quinquedentate, macrocycle formed by the Schiff-base condensation of 2.6-diacetylpyridine with 1.9-diamino-3.7-diazanonane (2,3,2-tet) in the presence of iron(i1) salts yields a series of iron(li1) complexes [Fe(C)X,] Y (C = macrocycle; X = CI, Br, NCS, or N,; and Y = Clod PF6, BPh4, FeCi4, or FeBr,).Spectroscopic, magnetic, and electric conductance measurements characterise the complexes as having high-spin seven-co-ordinate structures similar to those of the previously prepared complexes of the fifteen-membered macrocycle (B) derived from 2.6-diacetylpyridine and 1.8-diamino-3.6-diazaoctane (2,2,2-tet). The crystal and molecular structure of [Fe(C)(NCS),]CIO, (11) has been determined and that of [Fe( B) ( NCS),]C104 (I) redetermined. Crystals of (I) are monoclinic, space group P2,/c,Z = 4, with a = 8.946( 8), b = 14.504(13), c = 18.029(17) A, (3 = 92.66( 9)". Crystals of (11) are monoclinic, space group P2,la. Z = 4, with a = 17.349( 13), b = 12.1 51 (1 0 ) . c = 12.295(12) A, p = 110.61 ( 9)". The two structures were solved by Patterson and Fourier methods from 1 531 (I) and 1 473 (11) independent reflections collected by counter methods and refined to R 0.090 (I) and 0.077 (11). In both structures the metal atoms have distorted pentagonal bipyramidal environments with the isothiocyanate ligands in axial positions and the five nitrogen atoms of the macrocycle in equatorial positions. The Fe-N bond lengths and the conformation of the girdles are different in (I) and (11) as a consequence of the different ring sizes. The perchlorate anion in (I) is disordered. Reading RG6 2AD N. Ireland IN Part I the template synthesis of the first pentagonal bipyramidal complexes of iron ( 111) with a planar quinquedentate macrocyclic ligand (B) were described. The coordination geometry in the complexes [Fe(B)X,]ClO, (X = halide or pseudohalide) was established on the basis of various physical properties 1,2 and confirmed in the case of one member of the series, [Fe(B)(NCS)J-ClO,, by a preliminary single-crystal X-ray study.3 This showed refinement to R 0.16 before an adequate model for the disordered perchlorate group had been obtained. However, the analysis was sufficient to establish the planarity of the macrocycle and the (approximate) local D5h symmetry around the metal. More recently, Alcock et aL4 and Lindoy and Busch5 have reported a number of manganese@), zinc(II), and cadmium(I1) complexes of related quinquedentate complexes of related macrocycles having N5,4 N302,4 or N3S2 4 9 5 donor sets. From an X-ray structure deter-
