Premium
Preparative and structural studies of halodimolybdates(II). I. Preparation and crystal structure of (picH) 2 Mo 2 Br 6 (H 2 O) 2
Author(s) -
Brenčič J. V.,
Šegedin P.
Publication year - 1976
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.19764230312
Subject(s) - triclinic crystal system , crystallography , bond length , chemistry , crystal structure , molecule , molecular geometry , coordination sphere , hydrogen bond , pyridine , organic chemistry , medicinal chemistry
(picH) 2 Mo 2 Br 6 (H 2 O) 2 (picH = 4‐methylpyridinium cation) was prepared from (NH 4 ) 3 Mo 2 CI 9 · H 2 O and picHBr in 4 M aqueous HBr at −20°C. The compound crystallizes in the triclinic P 1 space group. The cell dimensions are: a = 7.822(5); b = 7.937(2), c = 10.163(7) Å α = 73.08(5)°; β = 85.46(3)°; γ = 74.25(1)°. For z = 1, d(calcd) = 2.55 gcm −3 , d(obsd) = 2.53(2) gcm −3 . The structure has been solved from 1191 independent reflections within the sphere bounded by θ = 30°, collected on a counter diffractometer, using MoK α radiation. Refinement led to final unweighted and weighted residuals of 0.035 and 0.041. Hydrogen atoms were not included. Structure consists of Mo 2 Br 6 (H 2 0)2 − of crystallographic Ci symmetry and two picH + ions. Br atoms and H 2 O molecules surround Mo 2 pair forming eclipsed configuration. The distance MoMo is 2.122(2) Å three independent MoBr bond lengths 2.589(2), 2.568(2) and 2.593(2) Å. H 2 O molecule is coordinated to Mo at 2.185(10) Å. Bond lengths and angles within the aromatic ring are normal. The compound is diamagnetic. Two water molecules are evolved when the substance is heated to 160°C in the inert atmosphere. The reaction with pyridine gives Mo 2 Br 4 Py 4 .