A Novel Layered Neodymium Squarate MOF Intercalating Free Ammonium and Squarate Ions {(NH4)2[Nd2(H2O)10(C4O4)3]C4O4}n: Synthesis, Crystal Structure and Thermal Decomposition

• Published in: Journal of inorganic and organometallic polymers and materials 2019-01, Vol.29 (1), p.302-307
• Main Authors: Bensaddek, Ali, Akkari, Hocine, Kinzhybalo, Vasyl
• Format: Article
• Language: English
• Subjects: Cations; Chemical synthesis; Chemistry; Chemistry and Materials Science; Communication; Coordination compounds; Crystal structure; Differential thermal analysis; Hydrogen bonds; Inorganic Chemistry; Ligands; Metal-organic frameworks; Neodymium; Organic Chemistry; Polymer Sciences; Thermal decomposition; Unit cell
• ISSN: 1574-1443; 1574-1451
• DOI: 10.1007/s10904-018-0967-8

The X-ray study of the title compound {(NH 4 ) 2 [Nd 2 (H 2 O) 10 (C 4 O 4 ) 3 ]C 4 O 4 } n (1) reveals that it crystallizes in the monoclinic system, space group P 2 1 / c (N°: 14), with unit cell parameters, a  = 7.483(3), b  = 27.866(7), c  = 6.766(2) Å and β  = 103.95(3)°. The crystal structure consists of a Nd–MOF/salt alternating layers, where neodymium–metal organic framework (Nd–MOF) layer lies in (200) plane, formed by isolated [NdO 9 ] polyhedra linked by bridging squarate ligands in µ 2 - and µ 4 -coordination modes. The salt layers lie at x  = 0 and are sandwiched between Nd–MOF layers; they consist of squarate anions and ammonium cations (in 1:2 ratio). Hydrogen bonds and π–π stacking play a pivotal role in structure cohesion between Nd–MOF layers leading to the formation of a 3D networks. The features of the IR spectrum are consistent with the crystal structure. The TG-DTA reveals that first water is lost from the coordination compound, and then the anionic ligands along with ammonium cations are removed leaving metal oxide as residue of the substance.