THE CRYSTAL STRUCTURES OF TRANS-(PicH-Pic)[MoCl4L2] AND ITS OXIDATION PRODUCT TRANS-[MoCl4L2] (Pic=4-Methylpyridine, L=4-Ethylpyridine)
B.Modec, J.V.Brencic,
L.Goli_1 and G.Giester2
1Faculty
of Chemistry and Chemical Technology, University of Ljubljana,
Aškerceva 5,
P.O.Box 537, 1001 Ljubljana, Slovenia, Jurij.Brencic@uni-lj.si
2Universität
Wien, Geozentrum, Institut für Mineralogie und Kristallographie,
Althanstrasse 14, A-1090 Wien, Austria
Keywords:Coordination Compounds of Molybdenum(III)
and Molybdenum(IV), 4-Ethylpyridine Ligand
Trans-(PicH-Pic)[MoCl4L2] (A) crystallizes from the solution of trans-(LH)[MoCl4L2] in the mixture of 4-Methylpyridine and acetonitrile. Slow oxidation of A by bromine gives trans-[MoCl4L2] (B) (L=4-Ethylpyridine, C7H9N; Pic=4-Methylpyridine, C6H7N).
A is monoclinic, P21/n, z=4 with: a=8.342(2), b=16.871(3), c=21.407(4) A and b=100.72(3)0,V=2960.1(4)A3. B is monoclinic as well, C2/m,z=2 with: a=16.108(1), b=7.663(1), c=7.157(1) A and b=98.01(1)0,V=875.4(1)A3. Molybdenum atoms are coordinated by four chlorine atoms and two 4-Ethylpyridine molecules defining nearly perfect octahedron. Both trans-[MoCl4L2]- and trans-[MoCl4L2] have eclipsed conformation of the organic ligands. Important dimensions are: Mo-Cl 2.430(3) and Mo-L 2.20(1)A for A and Mo-Cl 2.340(1) and Mo-L 2.190(3) for B. All octahedral angles are close to 90.0 and 1800.
Protonated 4-Methylpyridine is hydrogen bonded to another 4-Methylpyridine. N-H...N distance is 2.72(1)A. Hydrogen bonds of the same order of magnitude were found before [1,2]. Both structures were solved by direct methods and refined to R1=0.0436 for 4907 independent reflections for A and to R1 =0.0246 for 1189 independent reflections for B.