Two chiral metal–organic frameworks showing unprecedented pcu-type topology based on the vertex-shared bowl-like MNa3 SBUs

In the presence of NaOH, the self-assembly of M(CH3COO)2 and nitrilotriacetate generated two metal–organic polymers, MNa(NTA), (M = Pb(1), Sr(2), NTA3+ = the anion of nitrilotriacetate). The single crystal X-ray diffraction shows that polymers 1 and 2 are isostructural and display the chiral P213 space group with the Flack factor of −0.001(16) for 1 and 0.023(14) for 2. By topology analysis, the complicated architecture of 1 and 2 is simplified to be the 6-connected pcu-type net, which is built on the vertex-shared, bowl-like MNa3 SBUs (pcu = primitive centered cubic, SBU = secondary building unit).