Amino acid based MOFs: synthesis, structure, single crystal to single crystal transformation, magnetic and related studies in a family of cobalt and nickel aminoisophthales.
Four new 5-aminoisophthalates of cobalt and nickel have been prepared employing hydro/solvothermal methods: [Co(2)(C(8)H(5)NO(4))(2)(C(4)H(4)N(2))(H(2)O)(2)].3H(2)O (I), [Ni(2)(C(8)H(5)NO(4))(2)(C(4)H(4)N(2))(H(2)O)(2)].3H(2)O (II), [Co(2)(H(2)O)(mu(3)-OH)(2)(C(8)H(5)NO(4))] (III), and [Ni(2)(H(2)O)(mu(3)-OH)(2)(C(8)H(5)NO(4))] (IV). Compounds I and II are isostructural, having anion-deficient CdCl(2) related layers bridged by a pyrazine ligand, giving rise to a bilayer arrangement. Compounds III and IV have one-dimensional M-O(H)-M chains connected by the 5-aminoisophthalate units forming a three-dimensional structure. The coordinated as well as the lattice water molecules of I and II could be removed and inserted by simple heating-cooling cycles under the atmospheric conditions. The removal of the coordinated water molecule is accompanied by changes in the coordination environment around the M(2+) (M = Co, Ni) and color of the samples (purple to blue, Co; green to dark yellow, Ni). This change has been examined by a variety of techniques that include in situ single crystal to single crystal transformation studies and in situ IR and UV-vis spectroscopic studies. Magnetic studies indicate antiferromagnetic behavior in I and II, a field-induced magnetism in III, and a canted antiferromagnetic behavior in IV.
Sarma
Debajit
D
Framework Solids Laboratory, Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore-560012, India.
Ramanujachary
K V
KV
Lofland
S E
SE
Magdaleno
Travis
T
Natarajan
Srinivasan
S
D000596:Amino Acids / Q000737:chemistry*; D003035:Cobalt / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008280:Magnetics; D008958:Models, Molecular; D015394:Molecular Structure; D009532:Nickel / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D010795:Phthalic Acids / Q000737:chemistry*
D000596:Amino Acids; D009942:Organometallic Compounds; D010795:Phthalic Acids; D003035:Cobalt; D009532:Nickel