Synthesis of paramagnetic tetrakis(benzylisocyanide)bis(tri-p-tolylarsine oxide)cobalt(III) tetrafluoroborate. An example of oxidation of ligand and metal in reaction of pentakis(arylisocyanide)cobalt(II) with triarylarsine

Synthesis and Labile Ligand‐Substitution Reactions oftetrakis(Benzylisocyanide)bis‐(tri‐p‐tolylarsine‐oxide)cobalt(III) Perchlorate

“…Optimum temperature for the synthesis appears to be $ 23°C. [1] The similarity in the IR pattern is evidence for the presence of a Co -Co bond in a dimeric structure for [Co 2 (CNCH 2 Ph) 10 Figure 2, as previously assigned for the BF 4 complexes. Upon recrystallization only the Co(III) complex is recovered.…”

“…[1] Synthesis of [Co(CNCH 2 Ph) 4 -{OAs(C 6 H 4 Me-p) 3 } 2 ](ClO 4 ) 3 differed from that of [Co(CNCH 2 Ph) 4 -{OAs(C 6 H 4 Me-p) 3 } 2 ](BF 4 ) 3 in that sometimes a dark green compound formed, often as a tar, which required trituration for conversion to the golden yellow product. [1] Synthesis of [Co(CNCH 2 Ph) 4 -{OAs(C 6 H 4 Me-p) 3 } 2 ](ClO 4 ) 3 differed from that of [Co(CNCH 2 Ph) 4 -{OAs(C 6 H 4 Me-p) 3 } 2 ](BF 4 ) 3 in that sometimes a dark green compound formed, often as a tar, which required trituration for conversion to the golden yellow product.…”

“…The unique intermediate-spin, six-coordinate cobalt(III) complex, [Co(CNCH 2 Ph) 4 {OAs(C 6 H 4 Me-p) 3 } 2 ](BF 4 ) 3 , has been prepared by reaction of [Co 2 (CNCH 2 Ph) 10 ](BF 4 ) 4 ÁH 2 O with excess As(C 6 H 4 Me-p) 3 , [1] and recently shown to undergo labile ligand-substitution reactions with trialkylphosphine ligands. [2] Previous work with alkylisocyanide-Co(II) complexes, as well as triarylphosphine and trialkylphosphine-substituted alkylisocyanide-Co(I) and Co(II) complexes, has shown analogous behavior for the perchlorate and tetrafluoroborate salts, such as [Co 2 (CNCHMe 2 ) 10 ](-ClO 4 ) 4 Á5H 2 O and [Co 2 (CNCHMe 2 ) 10 ](BF 4 ) 4 Á5H 2 O, [3] 5 ](BF 4 ) 2 ÁxH 2 O, has also been observed.…”

Substitution and Redox Properties of Some Organoisocyanide Cobalt(II) Complexes

“…Reactions of cobalt(II)alkylisocyanide complexes with triarylphosphines have been studied and characterized as ligand substitution/reduction [10] with most reactions giving corresponding disubstituted five coordinate cobalt(I) complexes as final products, while the reactions of the cobalt(II) complexes with triarylarsines resulted in initial substitution, which at least in one case was accompanied by oxidation of the ligand to triarylarsine oxide and that of the cobalt (II) to cobalt(III) [12]. Spectra studies on these complexes suggested that some of them produce tetragonal structures in the solid state, while solution decomposition leads to tetrahedral geometry.…”

“…The five-coordinate alkylisocyanide complexes were known to generally react with tertiary phosphines to produce reduction/ligand substitution products of the type [Co(CNR) 3 (PR' 3 ) 2 ]X, X = ClO 4 or BF 4 [13][14][15], exceptions being reactions with tri-n-alkylphosphines, which led to disproportionation/ligand substitution products of the types [Co(CNR) 3 3 , has also been observed [12].…”