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Behaviour of Dimolyhdenum Tetraacetate in Aqueous Solutions of Hydrogen Halides. Synthesis and Crystal Structures of (pyH)2[Mo2(02CCH3)4Br2] and two Modifications of (pyH)2[Mo2(02CCH3 )4I2] (py =pyridine)

Ljubo Golič ; University Edvard Kardelj, Department of Chemistry, Murnikova 6. P.O.B. 537, 61001 Ljubljana, Yugoslavia
Ivan Leban ; University Edvard Kardelj, Department of Chemistry, Murnikova 6. P.O.B. 537, 61001 Ljubljana, Yugoslavia
Primož Šegedin ; University Edvard Kardelj, Department of Chemistry, Murnikova 6. P.O.B. 537, 61001 Ljubljana, Yugoslavia

Sažetak

The axial diadducts (pyH)2[Mo2(02CCHa)4X2], (py =pyridine,
X = Br, I) were isolated from solutions of dimolybdenum tetra-
• acetate in HX 1 : 1 after addition of pyridinium halide. (pyH)2
[Mo2(02CCHa)4Br2] (A) crystallizes in the space group I4/m with
a= 0.9746(2) nm, c = 1.3948(2) nm, V = 1.32484 nma and Z = 2.
Two modifications of the iodide analog were isolated. Triclinic
modification (B) crystallizes in the space group Pl with a= 1.0016(1)
nm, b = 1.0092(2) nm, c = 1.6325(2) nm, a = 74.75(1)0
, fJ = 71.38(2) 0 , r = 61.12(2)0
, V = 1.35747 nm3 mid Z = 2; tetragonal modification
(C) in the space group I4/mcm with a = 1.3086(1) nm, c = 1.4712(1)
nm, V = 2.51933 nm3 and Z = 4. The Mo - X (X = Br, I) distances,
found in anions [Mo2(02CCH3)4X2]2-, 287.9(3) pm in A, 326.2(1) pm
and 329.9(1) pm in B, and 320.4(1) pm in C are quite long, indicating
only weak axial coordination. Accordingly, the Mo - Mo distances
210.2(1) pm in A, 210.3(1) pm in B, and 210.2(1) pm in C are only
slightly longer than the Mo - Mo distance of 209.3(1) pm found in
Mo2(02CCHa)4.

Ključne riječi

Hrčak ID:

194125

URI

https://hrcak.srce.hr/194125

Datum izdavanja:

20.10.1984.

Posjeta: 1.005 *