From Helical Array to Porous Architecture: Exploring the Use of Side Chains of Amino Acids to Engineer 1D Infinite Coordination Polymeric Chain into Porous Frameworks

The self-assembly of d,l-amino acids and Cu(NO3)2·3H2O with 4,4‘-bipyridine in basic ethanol/aqueous solution
gave rise to two distinct three-dimensional (3D) supramolecular architectures {[Cu2(d-ala)(l-ala)(4,4‘-bipy)2](NO3)2·5H2O}n (1)
and {[Cu2(d-phe)(l-phe)(4,4‘-bipy)2](NO3)(OH)·5H2O}n (ala = alanine anion, phe = phenylalanine anion, 4,4‘-bipy = 4,4‘-bipyridine)
(2). In 1, Cu(II) centers chelated by deprotoned d,l-alanine direct linear 4,4‘-bipy to form a one-dimensional (1D) helical chain,
which is further assembled into 3D helical array through interchain hydrogen bonds and anion guest chains. In 2, Cu(II) centers
chelated by deprotoned d,l-phenylalanine direct 4,4‘-bipy to form a 1D twisted coordination polymeric chain that interacts with four
adjacent chains through complementary coordination interactions and two chains through weak π−π interactions to give a 3D
porous framework.