Coordination geometries of bis(4-amino-3-alkyl-1,2,4-triazole-5-thione) complexes of first-row transition metals: crystal structures of complexes with propyl and hydrogen in the 3-position. Relationship to the 3-methyl and 3-ethyl analogs
Rm. Mccarrick et al., Coordination geometries of bis(4-amino-3-alkyl-1,2,4-triazole-5-thione) complexes of first-row transition metals: crystal structures of complexes with propyl and hydrogen in the 3-position. Relationship to the 3-methyl and 3-ethyl analogs, INORG CHIM, 311(1-2), 2000, pp. 95-105
A series of bis bidentate complexes of 4-amino-3-propyl-1,2,4-triazole-5-th
ione SN4C5H10 (apt, 1) of the divalent ions Fe, Co, Ni, and Zn has been cry
stallized by direct combination of the ligand and metal nitrate or perchlor
ate hydrate salt in ethanol. The structures were determined by single-cryst
al X-ray diffraction techniques. In all the complexes, the triazole bonds t
o the metal ion through the amine and thione substituents on the five-membe
red ring. [Fe(apt)(2)(H2O)(2)](ClO4)(2) (2) has the like-ligands trans to e
ach other. The Fe-N distances (2.259(5) Angstrom) are elongated relative to
the Fe-O bond lengths (2.092(5) Angstrom). The compounds [Co(apt)(2)(H2O)(
2)](NO3)(2). 2H(2)O (3), [Ni(apt)(2)(H2O)(2)](NO3)(2). 2H(2)O (4), and [Zn(
apt)(2)(H2O)(2)](NO3)(2). 2H(2)O (5) are isostructural, with the water mole
cules cis to each other and the triazole ligands positioned with the amine
groups cis and S atoms trans. A series of complexes of 4-amino-1,2,4-triazo
le-5-thione (aht, 6) of divalent Mn, Co, and Zn has also been crystallized
by similar means and structurally characterized. [Mn(aht)(2)(H2O)(2)](ClO4)
(2) (7) has the ligands arranged as in 3, though with a non-centrosymmetric
packing (space group C-2). The cis Mn-N distances are significantly longer
(2.377(2) Angstrom) than the Mn-O distances (2.160(2) Angstrom). [Co(aht)(
2)(H2O)(2)](ClO4)(2) (8) possesses the trans geometry found in 2, though wi
th comparable Co-N and Co-O bond lengths (2.175(3) and 2.052(3) Angstrom).
[Zn(aht)(2)(H2O)(2)](ClO4)(2) (9) is isostructural with 7. These structures
are compared with those of two recently reported series of 4-amino-3-alkyl
-1,2,4-triazole-5-thione complexes (alkyl = methyl and ethyl) in order to g
auge the effect of the alkyl group on the coordination behavior of the tria
zole ligand towards the divalent first-row transition metals. (C) 2000 Else
vier Science B.V. All rights reserved.