ANTIFERROMAGNETISM OF COLLOIDAL [MN-O-CENTER-DOT-0.3THF](X)

The reduction of MnBr2 . 2THF (THF = tetrahydrofuran) using K[BEt3H] y ields the organosol [Mn . 0.3THF](x). According to the UV/Vis, ESR (el ectron spin resonance spectroscopy), HRTEM (high-resolution transmissi on electron microscopy), XPS (X-ray photoelectron spectroscopy) and XA S (X-ray absorption spectroscopy) data, this nanosized metal colloid c onsists of small THF-stabilized Mn-0 particles which show, in suscepti bility investigations, a diminished magnetic coupling as deduced from the Weiss temperature, Theta = 96 K, The Neel temperature TN is likewi se strongly reduced in comparison with the bulk value (95 K), The THF- stabilized Mn-0 particles exhibit superparamagnetism below 20 K, with a partial blocking at 10 K, and to our knowledge represent the first c olloid consisting of particles of an elemental antiferromagnetic metal , (C) 1998 John Wiley & Sons, Ltd.