Versatility within (4,4) networks assembled from 1,4-bis (n-alkyloxy)-2,5-bis(3,2′:6′,3′'-terpyridin-4′-yl)benzene and [Cu(hfacac)2] (Hhfacac=1,1,1,5,5,5-hexafluoropentane-2,4-dione)

The reactions of 1,4-bis(n-alkyloxy)-2,5-bis(3,2 ':6 ' ,3 ''-terpyridin-4 '-yl)benzene ligands with methoxy (1), ethoxy (2), n-propoxy (3), n-butyloxy (4), n-pentyloxy (5), n-hexyloxy (6), n-heptyloxy (7) and n-octyloxy (8) substituents with [Cu(hfacac)(2)].H2O (Hhfacac = 1,1,1,5,5,5-hexafluoropentane-2,4-dione) under conditions of crystal growth by layering have been investigated using different combinations of solvents. The products have been structurally characterized and in all cases, Cu(II) is octahedrally sited in a trans-{Cu(hfacac)(2)(N)(2)} environment in which N is a pyridine donor in one of the outer rings of a 3,2 ':6 ' ,3 ''-tpy unit. The coordination assemblies fall into four categories. The most populated class consists of (4,4) nets in which each bis(3,2 ':6 ' ,3 ''-tpy) ligand 1 and 4-8 acts as a 4-connecting node and the Cu(II) centres lie within the plane defined by the nodes; changes in conformation of the 3,2 ':6 ' ,3 ''-tpy units do not affect the assembly of the (4,4) network. One of two assemblies isolated with ligand 2 is also a (4,4) net, but powder X-ray diffraction (PXRD) data indicate that this is not representative of the bulk material. [Cu-2(hfacac)(4)(3)](n).5.5nC(6)H(5)Cl exhibits a unique structure consisting of a (4,4) net with the Cu(II) centres lying above and below the plane of the net. A third class of assembly was found for [Cu-3(hfacac)(6)(5)(2)](n) and comprises a (4,4) net in which half of the ligands are 4-connecting nodes and half coordinate through two pyridine rings and are therefore linkers; the efficient packing in this structure leaves no solvent-accessible voids. A 1D-coordination polymer in which all the bis(3,2 ':6 ' ,3 ''-tpy) ligands are 2-connecting linkers was observed for [Cu-2(hfacac)(4)(2)(2)](n).1.5nCHCl(3).4nMeOH and PXRD data confirm that the structure is representative of the bulk material. Structural studies have been complemented by thermogravimetic analyses of selected compounds.

Automated summary

The reactions of 1,4-bis(n-alkyloxy)-2,5-bis(3,2 ':6 ' ,3 ''-terpyridin-4 '-yl)benzene ligands with different substituents have been investigated, and four different coordination assemblies have been obtained.