NEW DINUCLEAR MOLYBDENUM(V) COMPLEXES WITH THIOLIGANDS
Marina Cindric, Višnja Vrdoljak, Biserka Prugovecki, Dubravka Matkovic-Calogovic and Boris Kamenar
Laboratory of General and Inorganic Chemistry, Chemistry Department, Faculty of Science, University of Zagreb, Ulica kralja Zvonimira 8, 10000 Zagreb, Croatia
E-mail: marina@zagreb.zoak.pmf.hr
Keywords: Crystal structures,
Molybdenum(V) complexes, Thiobenzoato complexes, 1,1,1-
Trifluorothioacetylacetone, Thioligands.
The fact that molybdenum-sulfur bonds are present in molybdoenzymes has extensively stimulated research in molybdenum complexes with sulfur ligand environments. This is particularly true for oxo complexes with molybdenum in its higher oxidation states [1,2].
In the continuation of our research on such complexes with thioligands, [3,4] from the reactions of [Mo2O3(acac)4] (acac = 2,4-pentandionato) with thiobenzoic acid and 1,1,1-trifluorothioacetylacetone we have isolated two novel complexes: [Mo2O2S2(OSCC6H5)2] (1) and [Mo2O3{CH3C(S)CHC(O)CF3}4] (2).
The neutral dimer (1) exhibits the affinity towards different donor ligands such as pyridine and g-picoline so that the corresponding [Mo2O2S2(OSCC6H5)2(C5H5N)2] (3) and [Mo2O2S2(OSCC6H5)2(C6H7N)2]×2H2O (4) complexes were also prepared.
|
(2) |
|
(3) |
The complexes (2), (3) and (4) were crystaline substances and their structures determined by X-ray structure analysis.
Crystal data for:
C20F12H16Mo2O7S4
(2), triclinic, space group P1, a =
8.392(4), b = 10.180(3), c = 10.448(4) A, a = 73.04(10), b = 71.48(2), g = 80.58(2) °, Z
= 1;
C24H20Mo2N2O4S4
(3), monoclinic, space group C2/c, a
= 14.453(3), b = 10.256(2), c = 18.547(3) A, b = 97.32(3) °, Z
= 4;
C26H28Mo2N2O6S4
(4), monoclinic, space group P21/c,
a = 13.917(2), b= 9.822(1), c = 24.781(6) A,
b =
102.36(2) °, Z = 4.
Each molybdenum atom in the centrosymetrical complex molecule of (2) is in a distorted octahedral coordination being bonded to two oxygen [2.184(4) and 2.098(4) A] and two sulfur atoms [2.448(2) and 2.462(2) A] from two bidentate 1,1,1- trifluorothioacetylacetonate ligands and to one bridging [1.855(7)] and one terminal oxo-oxygen [1.681(4) A] atom. As shown in Figure (2) the fluorine atoms of both 1,1,1- trifluorothioacetylacetonates are disordered over six positions. The complexes (3) and (4) are analogous and dinuclear, both containing Mo2O2S2 cores with two Mo atoms linked by a Mo-Mo single bond [2.822 in (3) ;2.831 in (4) A]. The Mo atoms are octahedrally coordinated by oxo-oxygen [1.685(5) in (3); 1.679(8) and 1.684(8) in (4) A], two bridging sulfido-sulfurs [2.316(2) in (3); 2.315(3) in (4) A], one nitrogen [2.305(5) in (3); 2.279(9) and 2.272(8) in (4) A] from pyridine or g-picoline molecules and one sulfur [2.580(2) in (3); 2.567(3) and 2.579(3) in (4) A] and oxygen [2.257(4) in (3); 2.263(8) and 2.270(7) in (4) A] atom from bidentately bonded thiobenzoato ligands. The complex molecule (3) has crystallographically imposed two-fold symmetry axis while the complex molecule (4) exhibits a pseudo two-fold symmetry.