Thermal and Magnetic Diversity in the Behaviour of the Cu super(II)-bdc-bpa System: 1D, 2D and Interpenetrated 3D Frameworks

• Published in: European journal of inorganic chemistry Vol. 2016; no. 29; pp. 4783 - 4791
• Main Authors: Bravo-Garcia, Laura, Barandika, Gotzone, Fidalgo-Marijuan, Arkaitz, Bazan, Begona, Urtiaga, Miren Karmele, Lezama, Luis, Arriortua, Maria Isabel
• Format: Journal Article
• Language: English
• Published: 01-10-2016
• Subjects: Behavior; Electronics; Ligands; Metal ions; Microwaves; Networks; Synthesis; X-rays
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.201600683

Metal organic frameworks (MOFs) are crystalline materials based on connections between metal ions through organic ligands. The combination of polycarboxylate anions and dipyridyl ligands is an effective strategy for producing extended structures. In this sense, the combination of bpa with m-bdc [bpa = 1,2-bis(4-pyridyl)ethane, m-bdc = 1,3-benzenedicarboxylate] has produced three new Cu super(II)-based networks with different dimensionalities, namely the 1D [Cu(m-bdc)(bpa) sub(0.5)(H sub(2)O)dmf].0.5H sub(2)O (1, synthesis based on sonication and slow evaporation), the 2D [Cu sub(6)(m-bdc) sub(6)(bpa) sub(6)(dmf) sub(3)].8dmf (2, microwave synthesis) and the 3D [Cu sub(4)(m-bdc) sub(4)(bpa) sub(2)dmf].dmf (3, microwave synthesis). The three compounds have been structurally characterized by means of single-crystal X-ray diffraction, IR and UV/Vis spectroscopy and elemental analysis. An unprecedented Cu super(II) dimer has been observed for compound 3. The thermal behaviour of the compounds was analysed by thermogravimetry (TG/DSC) and X-ray thermodifractometry (TDX), and it was concluded that the dimensionality plays an important role in their thermal properties. Electronic paramagnetic resonance and magnetic susceptibility measurements for compounds 1 and 3 showed that antiferromagnetic interactions exist between the metal ions. The combination of 1,2-bis(4-pyridyl)ethane and 1,3-benzenedicarboxylate ligands has led to three new Cu super(II)-based networks with different dimensionalities, namely the 1D [Cu(m-bdc)(bpa) sub(0.5)(H sub(2)O)dmf].0.5H sub(2)O, the 2D [Cu sub(6)(m-bdc) sub(6)(bpa) sub(6)(dmf) sub(3)].8dmf and the 3D [Cu sub(4)(m-bdc) sub(4)(bpa) sub(2)dmf].dmf (bdc = 1,3-benzenedicarboxylate, bpa = 1,2-bis(4-pyridyl)ethane).