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Discrete and polymeric cobalt organophosphates: isolation of a 3-D cobalt phosphate framework exhibiting selective CO2 capture

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Title Discrete and polymeric cobalt organophosphates: isolation of a 3-D cobalt phosphate framework exhibiting selective CO2 capture
 
Creator GUPTA, SK
KUPPUSWAMY, S
WALSH, JPS
MCINNES, EJL
MURUGAVEL, R
 
Subject SINGLE-MOLECULE-MAGNET
METAL-ORGANIC FRAMEWORK
ELECTRON-PARAMAGNETIC-RESONANCE
CARBON-DIOXIDE CAPTURE
TERT-BUTYL PHOSPHATE
IN-SITU FORMATION
ZEOLITE 13X
PHOSPHONATE CAGES
AUXILIARY LIGANDS
SWING ADSORPTION
 
Description Structurally diverse mononuclear, dinuclear, and tetranuclear cobalt organophosphates and a three-dimensional framework based on a D4R cobalt phosphate are reported. The role of auxiliary ligands in determining the nuclearity of the phosphate clusters has further been established. Reaction of cobalt acetate tetrahydrate with 2,6-di-iso-propylphenylphosphate (dippH(2)) in methanol or DMSO in the presence of ancillary N-donor ligands leads to the formation of mononuclear octahedral cobalt phosphate [Co(dippH)(2)(py)(4)] (1), dinuclear octahedral cobalt phosphates [Co(dipp)(NN)(MeOH)(2)](2)center dot 2MeOH (NN = bpy 2; phen 3), tetrahedral cobalt phosphates [Co(dipp)(L)(2)](2)center dot 2(MeOH) (L = imz 4; dmpz 5) and symmetric and asymmetric tetranuclear tetrahedral cobalt phosphates [Co(dipp)(2-apy)](4) (6) and [Co-4(dipp)(4)(2-apy)(3)(DMSO)]center dot(DMSO)center dot(H2O) (7), in nearly quantitative yields. The use of a linear N-donor ditopic linker, 3,6-di(pyridin-4-yl)-1,2,4,5-tetrazine (dptz), as the ancillary ligand leads to the formation of a robust three dimensional, four-fold interpenetrated network based on the D4R platform, {[Co(dipp) (dptz)(0.5)](4)}(n) (8), under ambient conditions. The new compounds have been characterized by analytical, thermo-analytical and spectroscopic techniques. Further, the molecular structures of compounds 1-8 have been established using single crystal X-ray diffraction studies. Compound 1 is a mononuclear complex in which the dippH ligands occupy trans-positions around the octahedral cobalt ion. The core structure of compounds 2-5, a Co2P2O4 ring, resembles the S4R (single-4-ring) SBU of zeolites, whereas the Co4P4O12 inorganic core found in compounds 6 and 7 resembles the D4R (double-4-ring) SBU. Cobalt organophosphate framework 8 shows significant CO2 adsorption at 273 K (7.73 wt% at 1 bar and 18.21 wt% at 15.5 bar) with high selectivity to CO2 uptake over N-2 and H-2 at 273 K. Magnetic studies of these symmetric complexes indicate the presence of weak antiferromagnetic interactions between the metal ions via the phosphate bridging moiety.
 
Publisher ROYAL SOC CHEMISTRY
 
Date 2016-01-15T06:49:33Z
2016-01-15T06:49:33Z
2015
 
Type Article
 
Identifier DALTON TRANSACTIONS, 44(12)5587-5601
1477-9226
1477-9234
http://dx.doi.org/10.1039/c4dt03379e
http://dspace.library.iitb.ac.in/jspui/handle/100/17974
 
Language en