Coordination polymers with divergent 4′-tert-butyl-4,2′:6′,4-terpyridine linkers: from aryl-aryl to ball-and-socket packing

The synthesis and structural characterization of 4'-tert-butyl-4,2': 6',4 ''-terpyridine (1) are presented, along with the first coordination polymers containing a 4,2': 6',4 ''-tpy ligand in which a non-aryl substituent is attached directly to the 4'-position. In [{ZnI2(1)center dot 1,2-Cl2C6H4}(n)], face-to-face pi-stacking between 1,2-Cl2C6H4 solvent molecules and 4,2':6',4 ''-tpy domains controls the assembly of the {ZnI2( 1)} n chains and this outweighs the steric effects of the Bu-t groups. The one-dimensional chains observed in [{Zn-2(mu-OAc)(4)(1)}(n)] and their packing in the solid state are closely related to those in [{Zn-2(m-OAc)(4)L}(n)] where L is 4'-phenyl-, 4'-(4-bromophenyl)- or 4'-(4-methylthiophenyl)-4,2':6',4 ''-terpyridine; the Bu-t group is accommodated in a similar sized cavity as each of the aryl substituents and in each polymer, the most important packing interactions are those between the 4,2':6',4 ''-tpy units. Reaction between 1 and Co(SCN)(2) results in the assembly of two-dimensional sheets containing octahedral trans-CoS2N4 nodes; tert-butyl groups protrude from both surfaces of the sheets, and a 'ball-and-socket' assembly supported by CHbutyl center dot center dot center dot N-pyridine hydrogen bonds locks the sheets together.