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

Citation
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
Citations number
23
Categorie Soggetti
Inorganic & Nuclear Chemistry
Journal title
INORGANICA CHIMICA ACTA
ISSN journal
00201693 → ACNP
Volume
311
Issue
1-2
Year of publication
2000
Pages
95 - 105
Database
ISI
SICI code
0020-1693(200012)311:1-2<95:CGOBC>2.0.ZU;2-V
Abstract
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.