Fa. Cotton et al., TRANSITION-METAL (MN, CO) AND ZINC FORMAMIDINATE COMPOUNDS HAVING THEBASIC BERYLLIUM ACETATE STRUCTURE, AND UNIQUE ISOMERIC IRON COMPOUNDS, Inorganica Chimica Acta, 266(1), 1997, pp. 91-102
Oxidation of Co-2(DPhF)(3) or hydrolysis of Co-2(DPhF)(4) (DPhF =N,N'-
diphenylformamidinate) gives Co4O(DPhF)(6) (I). This tetranuclear comp
ound consists of an oxygen atom centered in a tetrahedron of four-coor
dinate Co atoms with a DPhF bridge along each edge of the tetrahedron.
An idealized T-d symmetry is also found for zinc, II, and manganese,
III, analogs. The latter, Mn4O(DPhF)(6), crystallizes in a disordered
fashion so as to appear as two interpenetrating tetrahedra. Two mu(4)-
O tetrairon compounds, namely, Fe4O(DPhF)(6) (IV) and Fe4O(DBiPhF)(6)
(V) (DBiPhF = N,N'-bisbiphenylformamidinate) are also described. These
molecules are isomers of the Co, Zn and Mn molecules in that they hav
e the 'tetrahedron' of metal atoms badly distorted by a different dist
ribution of the formamidinate ligands. Two opposite Fe-Fe edges are do
ubly bridged, another two opposite edges are singly bridged and the re
maining two edges are unbridged. The lengths of these three pairs of o
pposite edges are short, medium and long and the idealized molecular s
ymmetry is only C-2. Crystal data for I.toluene at -60 degrees C are:
triclinic, space group P (1) over bar, a=13.426(3), b=13.491(3), c=22.
600(5) Angstrom, alpha=99.55(3), beta=95.39(3), gamma = 111.80(3)degre
es, Z= 2. For II.1.45C(6)H(14) at -60 degrees C: orthorhombic, space g
roup Pbca, a=23.8113(8), b=23.406(2), c=30.956(1) Angstrom, Z= 8. For
III at -150 degrees C: trigonal, space group R3, a = 23.440( 1), c = 1
0.708(1) Angstrom, Z= 3. For IV.1.5 toluene at -60 degrees C: triclini
c, spacegroup P (1) over bar, a = 14.920(3), b = 15.539(3), c= 19.027(
4) Angstrom, alpha= 84.63(3), beta = 85.67(3), gamma= 63.30(3)degrees,
Z= 2. (C) 1997 Elsevier Science S.A.