Uniform Sidearm Derivatisations in a Tetrapodal Pentaamine: Ligands with NN4 O4 Donor Sets, and a Bis(Ferrocenecarbaldehyde Aminal)

Z. Naturforsch. 55 b, 1037-1044 (2000); received July 28, 2000 Nonadentate Ligand, Schiff Base, Nickel The tetrapodal pentaamine 2,6-C5H3N[CMe(CH2NH2)2l2 (pyN_u 1) readily reacts with four equivalents of 2-hydroxyphenyl-substituted carbonyl compounds, such as (i) 2-hydroxybenzaldehyde, (ii) 2,4-dihydroxybenzaldehyde, (iii) 3,5-di-rm-butyl-2-hydroxybenzaldehyde, and (iv) 2-hydroxyacetophenone, to give the corresponding Schiff base derivatives with N N4O .1 donor sets (i: 2; ii: 3, iii: 4; iv: 5). With ligand 5, two transition metal complexes (M = Ni1 (6), Cu11 (7)) have been isolated, which are dinuclear and contain square-planar M(N202) units, linked by a pyridine-derived spacer whose nitrogen atom is uncoordinated. The reaction of 1 with ferrocenecarbaldehyde affords, under neutral conditions and irrespective of an excess of the aldehyde present, the bis(aminal) 8 as the major product, in which the two 1,3-propylenediamine subunits of 1 have condensed with two carbaldehyde moieties to give two 1,3-diazacyclohexane rings. All compounds have been characterised by IR spectroscopy and elemental analysis, as well as 'H and l3C NMR spectroscopy (except paramagnetic 7). The crystal structures of compounds 2, 6, 7, and 8 have been determined.