Comparison of copper imine and amine podates: geometric consequences of podand size and donor type

摘要

The imine podands tris[(2-nitrobenzylidene)aminoethyl]amine and tris[(2-nitrobenzylidene)aminopropyl]amine both stabilize copper(I), forming {tris[(2-nitrobenzylidene)aminoethyl]amine-κ N}copper(I) perchlorate aceto-nitrile disolvate, [Cu(CHNO)]ClO.2CHCN, (II), and {tris[(2-nitrobenzylidene)aminopropyl]amine-κ N}copper(I) perchlorate, [Cu(CHNO)]ClO, (VI), respectively. The larger propyl-based ligand is a poorer fit for the Cu ion. The reduced amine podand tris[(2-nitrobenzyl)aminoethyl]amine binds Cu and the resulting compound, chloro{tris[(2-nitrobenzyl)aminoethyl]amine-κ N}copper(II) chloride ethanol solvate, [Cu(CHNO)Cl]Cl.CHOH, (IV), shows both intra- and inter-molecular hydrogen bonding, which gives rise to RRS or SSR conformations in the podand strands rather than the expected pseudo-threefold symmetry.