Coordination polymers from calixarene-like [Cu2(dicarboxylate)2]4 building blocks:: Structural diversity via atropisomerism

The self-assembly Of [Cu-2(dicarboxylate)(2)](4) nanoscale secondary building units (nSBUs) into coordination polymers can occur in such a way that a range of calix-like atropisomers can exist. Eight compounds have been prepared and crystallographically characterized via reaction between Cu(NO3)(2) and angular dicarboxylate ligands: {[Cu-2(bdc)(2)(py)(2)](4).guest}(n), (1a), {[Cu-2(bdc)(2)(py)(2)](4).4nitrobenzene.2EtOH}(n), (1b), {[Cu-2(bdc)(2)(4-pic)(2)](4).4o-dichlorobenzene}(n) (2), {[Cu-2(5-OEt-bdc)(2)(py)(2)](4).8H(2)O}(n) (3), {[Cu-2(5-OPr-bdc)(2)(py)(2)](4).guest}(n) (4), {[Cu-2(pdc)(2)(py)(2)](4).4MeOH}(n), (5), {[Cu-2-(pdc)(2)(4-pic)(2)](4).4H(2)O}(n) (6), and {[Cu-2(tdc)(2)(MeOH)(2)](4).4naphthalene.8MeOH}(n) (7). The following atropisomers, all of which have also been observed in calixarenes, were observed: (a) cone (1a, 3, and 4); (b) partial cone (1b); (c) 1,2-alternate (2 and 5-7); and (d) 1,3-alternate (1a, 3, and 4). The similarities and differences between the crystal structures of 1-7 are detailed herein.