Self-assembled Transition Metal Coordination Frameworks of ...

Chapter 3 _ _ __
3.2. Experimental
3.2.1. Materials
Nickel(ll) chloride hexahydrate (Merck), nickel(Il) perchlorate hexahydrate
(Merck) and ammonium hexafluorophosphate (Fluka) were used as supplied and
solvents were purified by standard procedures before use.
Caution! Perchlorate complexes of metals with organic ligands are potentially
explosive and should be handled with care.
3.2.2. Synthesis of Ni(II) complexes
[Nr(HL’)1.(PF.).~ 1 mo (1)
To a hot solution of H2L' (0.440 g, l mmol) in 50 ml methanol was added an
equimolar amount of nickel(ll) chloride hexahydrate (0.240 g) dissolved in 10 ml hot
methanol. The brown colored mixture was refluxed for an hour and added NH4PF6 (2
mmol, 0.332 g) in 20 ml methanol and refluxed 2 more hours and allowed to stand at
room temperature. The brown crystalline compound precipitated was filtered, washed
with methanol and ether, recrystallized in acetonitrile: ethanol mixture and dried in
vacuo over P4010. Yield: 0.440 g (63%). Elemental Anal. Found (Calc.): C, 39.72
(40.00); H, 2.98 (3.28); N, 16.76 (16.22); S, 4.99 (4.64)%.
Crystals suitable for X-ray analysis were obtained by slow evaporation of a
solution of the compound in ethanol-methanol mixture. The complex 1 crystallized as
[Ni(HL')]4(PF(,)4- '/zCH3CH2OH- 2.8H2O (la) and the relatively high R-factors of la
are due to the bad quality of the crystal. All attempts to get better quality crystals
failed.
[Nz2(HL-*)L-*];(P1=".)2- 7H2O (2)
The preparation of the compound 2 was carried out in a similar way as that of
compound 1, except that the ligand H2143 (0.387 g, l mmol) was used instead of H2L'.
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