Multitopic 3,2':6',3''-terpyridine ligands as 4-connecting nodes in two-dimensional 4,4-networks

The tetratopic 1,4-bis(2-phenylethoxy)-2,5-bis(3,2':6',3''-terpyridin-4'-yl)benzene (1) and 1,4-bis(3-phenylpropoxy)-2,5-bis(3,2':6',3''-terpyridin-4'-yl)benzene (2) ligands have been prepared and fully characterised. Combination of ligand 1 or 2 and [M(hfacac)₂]·xH₂O (M = Cu, x = 1; M = Zn, x = 2) under conditions of crystal growth by layering led to the formation of [Cu₂(hfacac)₄(1)] ·3.6n(1,2-Cl₂C₆H₄)·2nCHCl₃, [Zn₂(hfacac)₄(1)] ·nMeC₆H₅·1.8nCHCl₃, [Cu₂(hfacac)₄(2)] ·nMeC₆H₅·2nH₂O, [Cu₂(hfacac)₄(2)] ·2.8nC₆H₅Cl and [Cu₂(hfacac)₄(2)] ·2n(1,2-Cl₂C₆H₄)·0.4nCHCl₃·0.5nH₂O. For each compound, single-crystal X-ray analysis revealed the assembly of a planar (4,4)-net in which the tetratopic ligands 1 or 2 define the nodes. The metal centres link two different bis(3,2':6',3''-tpy) ligands via the outer pyridine rings; whereas copper(ii) has N-donors in a trans-arrangement, zinc(ii) has them in cis. This difference between the copper(ii) and zinc(ii) coordination polymers modifies the architecture of the assembly without changing the underlying (4,4)-network.