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Hybrid Polyfunctional Systems Based on Nickel(II) Isonicotinate
Author(s) -
Cortijo Miguel,
Herrero Santiago,
JiménezAparicio Reyes,
Perles Josefina,
Priego José L.,
Torralvo M. José,
Torroba Javier
Publication year - 2013
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201201461
Subject(s) - chemistry , microporous material , nickel , thermogravimetric analysis , molecule , metal organic framework , adsorption , yield (engineering) , elemental analysis , crystallography , solvent , anhydrous , metal , inorganic chemistry , organic chemistry , materials science , metallurgy
Several metal–organic frameworks of nickel(II) were obtained starting from the molecular complex 1 , [Ni(OH 2 ) 4 (4‐pyc) 2 ] (4‐pyc = 4‐pyridinecarboxylate or isonicotinate). By using different reaction conditions, two polymorphs of the anhydrous complex [Ni(4‐pyc) 2 ] n ( 2a and 2b ) and the polynuclear compound [Ni 5 (OH 2 ) 3 (4‐pyc) 10 ] n ( 3 ) were obtained in very high yield. All of the compounds were characterized by elemental analysis and spectroscopic data. The crystal structure determination of compounds 2b and 3 was also carried out. Structural and topological analysis of these new structural types and other related ones were performed. It was found that compounds 2a and 2b are a rare case of coordination framework isomers. Thermogravimetric studies indicate that compounds 2b and 3 lose the pore‐allocated solvent molecules at moderate temperatures without any significant structural change, and at higher temperatures, compounds 1 and 3 are transformed into 2a . Textural parameters that characterize the microporous networks for 2b and 3 were obtained by nitrogen‐adsorption measurements. For both samples, the micropore size distribution indicates cylindrical pores with diameters of 0.85 ( 2b ) and 0.90 nm ( 3 ). The values of Brunauer–Emmett–Teller and Langmuir surface areas are 178 and 185 m 2 g –1 for compound 2b , and 995 and 982 m 2 g –1 for compound 3 . Micropore volumes are 0.065 and 0.350 cm 3 g –1 for 2b and 3 , respectively. The magnetic properties of compounds 1 , 2a , and 2b are consistent with the presence of zero‐field splitting and a small antiferromagnetic coupling between the metal atoms. The magnetic properties of the pentanuclear compound 3 were analyzed by considering one monomer with zero‐field splitting caused by axially distorted Ni II octahedral compounds, and two dimeric fragments with magnetic interactions within each dimetallic unit.