Tetrahedral Co II Complexes with CoI 2 O 2 and CoO 2 S 2 Cores – Crystal Structures of [Co{HN(OPPh 2 )(SPPh 2 )‐ O } 2 I 2 ] and [Co{N(OPPh 2 )(SPPh 2 )‐ O , S } 2 ]

The compound [Co II {HN(OPPh 2 )(SPPh 2 )‐ O } 2 I 2 ] ( 1 ) was synthesised by the reaction of cobalt in powder with the iodine adduct of tetraphenylthiooxoimidodiphosphinic acid, HN(OPPh 2 )(SPPh 2 ), in Et 2 O; treatment of compound 1 with NaOH resulted in deprotonation of the ligands bound to the metal ion and a separation of [Co II {N(OPPh 2 )(SPPh 2 )‐ O , S } 2 ] ( 2 ). Molecular structures of complexes 1 and 2 were elucidated by X‐ray diffraction analysis, which revealed a CoI 2 O 2 tetrahedral core for compound 1 in which two neutral ligands bind through the oxygen atoms the Co II ion, and a tetrahedral CoO 2 S 2 core for compound 2 with the oxygen and sulfur atoms of each anionic ligand chelating a Co II centre. Variable‐temperature magnetic susceptibility measurements are consistent with tetrahedral high‐spin ( S = 3/2) Co II that possesses a 4 A 2 ground state with best fit parameters g = 2.25, | D | = 12.0 cm –1 and g = 2.37, | D | = 11.9 cm –1 for complexes 1 and 2 , respectively. The compounds were further characterised by UV/Vis and IR spectroscopy. DFT calculations were performed on model complexes [Co II {N(OPH 2 )(SPH 2 )‐ O , S } 2 ] ( 3 ) and [Co II {N(SPH 2 ) 2 ‐ S , S′ } 2 ] ( 4 ) to compare the electronic properties of the CoO 2 S 2 and CoS 4 cores. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)