A Series of Ca(II) or Ba(II) Inorganic–Organic Hybrid Frameworks Based on Aromatic Polycarboxylate Ligands with the Inorganic M–O–M (M = Ca, Ba) Connectivity from 1D to 3D

Solvothermal reactions of Ca­(NO3)2 or Ba­(NO3)2 with aromatic carboxylate ligands
afforded four
new inorganic–organic hybrid frameworks, [Ca­(PBDC)­(H2O)3]n (1), [Ca­(OBDC)­(H2O)]n (2), [Ba5(OBDC)4(H2O)2(NO3)2]n (3), and
[Ba3(BTC)2(H2O)4]n (4) (H2PBDC = terephthalic
acid, H2OBDC = phthalic acid, H3BTC = 1,3,5-benzenetricarboxylic
acid). These compounds have been fully characterized by single crystal
X-ray diffraction, powder X-ray diffraction, satisfactory elemental
analysis, IR spectra, and TG analysis. X-ray analysis shows that compound 1 features a one-dimensional chain (1D) structure with the
I1O0 connectivity, both compound 2 and compound 3 feature a two-dimensional (2D) layer
structure with the I1O1 connectivity, I2O0 connectivity, respectively, compound 4 features a three-dimensional (3D) framework with a rare I3O0 connectivity. Thermal stabilities and luminescent properties
of compounds 1–4 and NLO property
of compound 4 have also been investigated.