ISSN:
1573-1111
Keywords:
trans-4-styrylpyridine complex
;
Werner-type clathrates
;
crystal structure
;
IR spectra
;
electronic spectra and thermal analysis
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract New clathrate inclusion compounds with the general formula,MA3X2 β 1/2G (M = Co(II)(1),Cd(II)(2), and Zn(II)(3), X = NO3 - andA and G = trans-4-styrylpyridine), differing from the usualWerner clathrates, MA4X2 β2G, have been prepared and characterized by elemental and thermal analyses,IR and electronic spectroscopy and X-ray crystallography. Tworepresentative compounds [Co(stpy)3(NO3)2] β 1/2stpy (1) and [Cd(stpy)3(NO3)2] β 1/2 stpy (2)are investigated by single crystal X-ray diffraction. Compound (1)crystallizes in the triclinic space group P¯1 with a = 10.966(2),b = 12.802(4), c = 16.063(5) Å α = 83.38(3),β = 71.30(2), γ = 76.88(3) °,Z = 2. The structure is made up of discretemolecules of [Co(stpy)3(NO3)2]. The central Co(II) issurrounded by three stpy nitrogen atoms and four oxygen atoms of twoasymmetrically coordinated bidentate nitrate ligands. One of the oxygensis semicoordinated leading to a distorted octahedral geometry for Co(II).Compound (2) crystallizes in the monoclinic space group P21/nwith a = 15.597(3), b = 18.313(5), c = 16.188(3) Åβ = 115.998(14)° and Z = 4. The structure consists of neutralmolecules of [Cd(stpy)3(NO3)2]. The geometry aroundCd(II) is best described as pentagonal bipyramid with four oxygen atomsfrom symmetrical bidentate nitrate groups and one stpy nitrogen atom inthe equatorial positions. Two other nitrogen atoms from stpy ligands occupythe axial positions. The guest stpy molecules are trapped in the centrosymmetricalcavities in lattices of both 1 and 2. Compound 3is found to beisomorphous with 2. A large splitting of the symmetric and asymmetricNO2 stretching vibrations reveals the presence of bidentate nitrate ligands.Thermogravimetric and DTA studies on the Cd(II) compound, show it to be athermally stable inclusion compound.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1008137311908
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