title: Structure and magnetism of a mixed-valence octanuclear manganese(II/III) cluster derived from carbamoylcyanonitrosomethanide (ccnm).
abstract: A mixed-valence octanuclear manganese complex of formula [Mn(II)(4)Mn(III)(4)O(4)(ccnm)(12)]·4MeCN·7H(2)O (1·4MeCN·7H(2)O) (ccnm = carbamoylcyanonitrosomethanide) has been synthesized and characterized by single crystal X-ray diffraction, IR spectroscopy, elemental analysis and magnetic measurements. The metal core of 1 adopts a tetra-capped (with Mn(II) ions) distorted [Mn(III)(4)O(4)](4+) cubane topology, with a three-J magnetic analysis indicating that the cluster displays dominant antiferromagnetic interactions. Three equally possible fits were obtained, all leading to a spin ground state of S = 0 with S = 1, 2 and 3 close in energy. Comparisons of the magnetic analysis are made with that published for a related Mn(8) cluster and, more generally, with other Mn(III)Mn(III) and Mn(III)Mn(II) fragments in clusters of various types.
authors.affiliation: School of Chemistry, Monash University, Wellington Rd, Clayton, Victoria 3800, Australia.
authors.forename: Mohd R
authors.initials: MR
authors.lastname: Razali
authors.forename: Anthony S R
authors.initials: AS
authors.lastname: Chesman
authors.forename: Nicholas F
authors.initials: NF
authors.lastname: Chilton
authors.forename: Stuart K
authors.initials: SK
authors.lastname: Langley
authors.forename: Boujemaa
authors.initials: B
authors.lastname: Moubaraki
authors.forename: Keith S
authors.initials: KS
authors.lastname: Murray
authors.forename: Glen B
authors.initials: GB
authors.lastname: Deacon
authors.forename: Stuart R
authors.initials: SR
authors.lastname: Batten