Polynuclear chromium(III) carboxylates. 1. Synthesis, structure, and magnetic properties of an octanuclear complex with a ring structure
A novel cyclic octanuclear chromium(III) complex with hydroxo and acetato bridging ligands was isolated and its structure determined by X-ray crystallography. The complex [Cr{sub 8}(OH){sub 12}(OAc){sub 12}] (1) (OAc{sup {minus}} = CH{sub 3}CO{sub 2}{sup {minus}}), as found in crystals of 1{center_dot}34H{sub 2}O, is obtained by refluxing an aqueous solution of the trinuclear basic chromium acetate. 1{center_dot}34H{sub 2}O crystallizes in the tetragonal space group I{bar 4}2d with the following unit cell dimensions: a = 16.592(2) {angstrom}, c = 31.557(4) {angstrom}, V = 8687(1) {angstrom}{sup 3}, and Z = 2. A total of 2,000 unique data with I > 3{sigma}(I) were used to solve and refine the structure to R(F{sub o}) = 0.066 and R{sub w}(F{sub o}) = 0.085. The structure consists of eight Cr(III) ions that form a ring structure and are bridged by hydroxo and acetato ligands. Each of the two neighboring metal atoms in 1 is bridged either by two OH{sup {minus}} ligands and one OAc{sup {minus}} ligand, with a Cr{hor_ellipsis}Cr distance of 2.949(2) {angstrom}, or by two OAc{sup {minus}} ligands and one OH{sup {minus}} ligand, with a Cr{hor_ellipsis}Cr distance of 3.383(2) {angstrom} in an alternating fashion. The complex resides on a crystallographic 4 center, and the overall symmetry of 1 is S{sub 4}. The magnetic susceptibility of 1{center_dot}34H{sub 2}O was measured in the temperature range of 5--240 K. Theoretical modeling of the susceptibility data indicates alternating antiferromagnetic exchange interactions between adjacent spin 3/2 Cr{sup 3} ions around the ring, of magnitude J/k{sub B} = 13.7 and 8.9 K, respectively.
- Research Organization:
- Hebrew Univ. of Jerusalem (IL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-82
- OSTI ID:
- 20050827
- Journal Information:
- Inorganic Chemistry, Vol. 39, Issue 7; Other Information: PBD: 3 Apr 2000; ISSN 0020-1669
- Country of Publication:
- United States
- Language:
- English
Similar Records
Crystal structure of ether solvate of octanuclear lutetium aluminohydride complex [(Bu{sub 2}{sup t}C{sub 5}H{sub 3})LuH]{sub 4}[Et{sub 2}O{center_dot}AlH{sub 4}]{sub 2}[AlH{sub 4}]{sub 2}{center_dot}Et{sub 2}O
Structural characterization of paramagnetic, triangulo niobium clusters, Cp'/sub 3/Nb/sub 3/Cl/sub 3/(/mu//sub 2/-Cl)/sub 3/(/mu//sub 3/-O)(/mu//sub 3/-X) (X = OH, Cl)