A. Grohmann, F. Heinemann, P. Kofod
Mar 2, 1999
Citations
0
Influential Citations
9
Citations
Journal
Inorganica Chimica Acta
Abstract
The pentaamine methylcobalt(III) compound [Co(pyN 4 )(CH 3 )](NO 3 ) 2 (pyN 4 =2,6-bis(1′,3′-diamino-2′-methyl-prop-2′-yl)pyridine) has been synthesised from [Co(NH 3 ) 5 (CH 3 )](NO 3 ) 2 and pyN 4 by ligand exchange, and characterised by IR, 1 H, 13 C and 59 Co NMR spectroscopy as well as elemental analysis. The structure of the complex has been determined using the dithionate salt [Co(pyN 4 )(CH 3 )]S 2 O 6 . The coordination geometry at cobalt is close to octahedral, the tetrapodal pentadentate amine ligand providing a C 2 -symmetrical coordination cap for the metal centre. One axial position is occupied by the pyridine nitrogen atom, while the four equivalent primary amino groups take the equatorial positions. The other axial position, trans to the pyridine ring, is occupied by the methyl group. The Co–N py bond length of 2.018(2) A is significantly elongated compared with other cobalt(III) complexes of the pyN 4 ligand, demonstrating the strong trans influence of the CH 3 ligand. The Co–C bond length (1.975(4) A) is virtually identical to the value found in the related complex [Co(NH 3 ) 5 (CH 3 )](S 2 O 6 ).