Reactions of Pentakis (Arylisocyanide)Cobalt(II) Perchlorate with Triphenylarsine and Triphenylstibine

The Co(II) complex, [Co(CNC 6 H 4 Me-o) 4 (ClO 4 ) 2 ], was synthesized from [Co(CNC 6 H 4 Me-o) 5 ](ClO 4 ) 2 by reaction with AsPh 3 , SbPh 3 , and incomplete dissolutuion in CH 2 C1 2 . Analogous procedures on [Co(CNPh) 5 ](ClO 4 ) 2 .H 2 O failed to produce a tetrakis complex. These results confirm that stability and ease of synthesis for the [Co(CNR) 4 (ClO 4 ) 2 ] complexes parallel steric hindrance of the aryl group, R = 2,6-(CHMe 2 ) 2 C 6 H 3 > 2,6-Et 2 C 6 H 3 > 2,6-Me 2 C 6 H 3 > o-MeC 6 H 4 > C 6 H 5 . Physical properties for [Co(CNC 6 H 4 Me-o) 4 (ClO 4 ) 2 ] and [Co(CNC 6 H 4 Me-o) 5 ]ClO 4 are reported; ClO 4 - coordination in [Co(CNC 6 H 4 Me-o) 4 (ClO 4 ) 2 ] is concluded because the physical properties are so analogous to those of other known [Co(CNR) 4 (ClO 4 ) 2 ] complexes.