title: The first structurally confirmed paddlewheel compound with an M(2)(7+) core: [Os(2)(hpp)(4)Cl(2)](PF(6)).
abstract: Oxidation of Os(2)(hpp)(4)Cl(2), 1 (hpp = the anion of 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine), with (FeCp(2))PF(6) produces air-stable [Os(2)(hpp)(4)Cl(2)]PF(6), 2. This is the first structurally confirmed metal-metal bonded paddlewheel compound having an M(2)(7+) core. The Os-Os distances for two crystalline forms, 2.2acetone and 2.hexane, are 2.3309(4) and 2.3290(6) A, respectively. EPR, (1)H NMR, and magnetization data indicate that 2 has an unpaired electron and an exceptionally low g value of 0.791 +/- 0.037. An electrochemical study shows that there is a quasireversible wave corresponding to a more highly oxidized species with an unprecedented Os(2)(8+) core.
authors.affiliation: Department of Chemistry and Laboratory for Molecular Structure and Bonding, Texas A&M University, College Station, Texas 77842-3012, USA.
authors.forename: F Albert
authors.initials: FA
authors.lastname: Cotton
authors.forename: Naresh S
authors.initials: NS
authors.lastname: Dalal
authors.forename: Penglin
authors.initials: P
authors.lastname: Huang
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Murillo
authors.forename: Ashley C
authors.initials: AC
authors.lastname: Stowe
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Wang