Transformation from a 2D stacked layer to 3D interpenetrated framework by changing the spacer functionality: Synthesis, structure, adsorption, and magnetic properties

Tapas Kumar Maji, Masaaki Ohba, Susumu Kitagawa

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Abstract

Two novel coordination polymers of Cu(II), viz. [Cu(bipy)(1,4-napdc)(H 2O)2]n (1) and {[Cu(bpe)1.5(1,4- napdc)](H2O)}n (2) (bipy = 4,4′-bipyridine; bpe = 1,2-bis(4-pyridyl)ethane; 1,4-napdc2- = 1,4-naphthalenedicarboxylate) , have been synthesized and structurally characterized by changing only the pillar motifs. Both the compounds crystallize by slow evaporation from the ammoniacal solution of the as-synthesized solid. Framework 1 crystallizes in monoclinic crystal system, space group P2/n (No. 13), with a = 11.028(19) A, b = 11.16(3) Å, c = 7.678(13) Å, β = 103.30(5)°, and Z = 2. Framework 2 crystallizes in triclinic system, space group, P1 (No. 2), a = 10.613(4) Å, b = 10.828(10) Å, c = 13.333(9) Å, α = 85.25(9)°, γ = 82.59(6)°, γ = 60.37(5)°, and Z = 2. The structure determination reveals that 1 has a 2D network based on rectangular grids, where each Cu(II) is in 4 + 2 coordination mode. The 2D networks stacked in a staggered manner through the π-π interaction to form a 3D supramolecular network. In the case of 2, a {Cu(bpe)1.5}n ladder connected by 1,4-napdc2- results a 2D cuboidal bilayer network and each bilayer network is interlocked by two adjacent identical network (upper and lower) forming 3-fold interpenetrated 3D framework with small channel along the c-axis, which accommodates two water molecules. The TGA and XRPD measurements reveal that both the frameworks are stable after dehydration. Adsorption measurements (N2, CO2, and different solvents, like H2O, MeOH, etc.) were carried out for both frameworks. Framework 1 shows type-II sorption profile with N2 in contrast to H 2O and MeOH, which are chemisorbed in the framework. In case of 2, only H2O molecules can diffuse into the micropore, whereas N 2, CO2, and MeOH cannot be adsorbed, as corroborated by the smaller channel aperture. The low-temperature (300-2 K) magnetic measurement of 1 and 2 reveals that both are weakly antiferromagnetically coupled (J = -1.85 cm-1, g = 2.02; J = -0.153 cm-1, g = 2.07), which is correlated by the magnetic pathway to the corresponding structure.

Original languageEnglish
Pages (from-to)9225-9231
Number of pages7
JournalInorganic chemistry
Volume44
Issue number25
DOIs
Publication statusPublished - Dec 12 2005
Externally publishedYes

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All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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