Phosphoraneiminato Complexes of Manganese and Cobalt with Heterocubane Structure

✍ Scribed by Ulrike Riese; Naim Faza; Werner Massa; Klaus Harms; Thees Breyhan; Paul Knochel; Jürgen Ensling; Vadim Ksenofontov; Philipp Gütlich; Kurt Dehnicke

• Book ID: 101306121
• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: German
• Weight: 135 KB
• Volume: 625
• Category: Article
• ISSN: 0372-7874
• DOI: 10.1002/(sici)1521-3749(199909)625:9<1494::aid-zaac1494>3.0.co;2-u

✦ Synopsis

The phosphoraneiminato complexes [MnBr(NPEt 3 )] 4 (1) and [M 4 Br 5 {NP(NMe 2 ) 3 } 3 ] with M = Mn (2) and M = Co (3) are prepared by melting reactions from the anhydrous metal dibromides with the silylated phosphaneimines Me 3 SiNPR 3 (R = Et, NMe 2 ) in the presence of potassium fluoride. All complexes are characterized by crystal structure analyses. 1 forms an only slightly distorted Mn 4 N 4 heterocubane skeleton with an approximate T d symmetry and short Mn ´´´Mn distances of average 295.7 pm. In the structures of 2 and 3 one l 3 -NPEt 3 ligand of 1 is replaced by one bromine atom with l 3 -function. This leads to the novel heterocubane type M 4 N 3 Br with approximate C 3 symmetry. The deformation of the cubic skeleton leads to metal-metal distances of different lengths, i. e. 292.7 and 323.6 pm in 2 and 274.4 and 306.2 pm in 3. Temperature dependent magnetic susceptibility measurements between 300 and 5 K on 1 have shown that strong antiferromagnetic coupling exists between the Mn(II) ions with S = 5/2, with a large negative Weiss constant of H = ±694 K.