Comprehensive Study on Mutual Interplay of Multiple V‑Shaped Ligands on the Helical Nature of a Series of Coordination Polymers and Their Properties

V-shaped ligands are commonly used
for helical coordination polymer synthesis. However, employment of
multiple V-shaped ligands does not always lead to a helical network.
The mutual interplay of two V-shaped ligands, which is neither easily
predictable nor well documented, plays a major role directing the
self-assembly of the resultant network. We report here the construction
of a series of novel coordination polymers {[Ni­(OBA)­(H2MDP)­(H2O)]·(DMF)3}n (1),{[Ni­(FBA)­(H2MDP)]·(H2O)3·(DMF)}n (2),{[Ni2(IPA)2(H2MDP)2(H2O)]·(H2O)­(DMF)}n (3),{[Ni­(ADA)­(H2MDP)]·(MeOH)}n (4),[Ni­(TNBA)­(H2MDP)2]n (5),
{[Ni­(PPA)­(H2MDP)2]·(H2O)2}n (6), {[Ni­(HDPA)2(H2MDP)2]}n (7), and [Ni­(SBA)­(H2MDP)]n (8) {where H2OBA = 4,4′-oxybis­(benzoic acid), H2FBA = 4,4′-(hexafluoroisopropylidene)­bis­(benzoic
acid), H2IPA = isophthalic acid, H2ADA =1,3-adamantanediacetic
acid, H2TNBA = 5,5′-dithiobis­(2-nitrobenzoic acid),
H2PPA 1,4-phenylenedipropionic acid, H2DPA =
diphenic acid H2SBA= 4,4′-sulfonyldibenzoic acid}
using a combination of mixed V-shaped ligands. The deployment of bent
ligands yields a rich variety of network topologies with various helical
motifs comprising both the linkers and the individual one. A detailed
gas sorption study of porous networks, as evident from the presence
of distinct nanoporous voids and channels inside the structures, is
also investigated. Furthermore, chirality associated with helical
networks and their role as potential functional materials are verified
by solid state circular dichroism spectra.