Straight versus branched chain substituents in 40-(Butoxyphenyl)-3,20:60,3"-terpyridines: Effects on (4,4) coordination network assemblies

Abstract

The preparation and characterization of the isomers rac-40-(4-butan-2-yloxyphenyl)-3,20:60, 3"-terpyridine (rac-2), 40-(2-methylpropoxyphenyl)-3,20:60,3"-terpyridine (3) and 40-(tert-butoxyphen yl)-3,20:60,3"-terpyridine (4) are reported. The compounds react with Co(NCS)2 under conditions of crystal growth at room temperature to give single crystals of [{Co(rac-2)2(NCS)2}•CHCl3]n, [Co(3)2(NCS)2']n and [{Co(4)2(NCS)2}•CHCl3]n which possess (4,4) networks, with the Co centers acting as 4-connecting nodes. Powder X-ray diffraction (PXRD) was used to confirm that the crystals chosen for single crystal X-ray diffraction were representative of the bulk samples. The detailed structures of the three networks have been compared with that of the previously reported [{Co(1)2(NCS)2}•4CHCl3]n in which 1 is 40-(butoxyphenyl)-3,20:60,3"-terpyridine. Whereas the switch from 1 with the straight-chain butoxy substituent to rac-2, 3 and 4 with branched chains causes significant structural perturbation, changes in the spatial properties of the branched substituents are accommodated with subtle conformational changes in the 3,20:60,3"-tpy domain.