2 research outputs found
Group VI Metal Carbonyl Complexes of Bis((diphenylphosphino)methyl)diphenylborate and an Assessment of Their Utility for Template Ligand Syntheses
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group VI metal chemistry of anionic bis((diphenylphosphino)methyl)diphenylborate
(Ph<sub>2</sub>BP<sub>2</sub>) offers some surprises in comparison
to the chemistry of analogous complexes of neutral bidentate phosphines.
The enhanced donor ability of Ph<sub>2</sub>BP<sub>2</sub> relative
to related bis-PPh<sub>2</sub> ligands is confirmed by IR spectral
analysis of [ASN][M(CO)<sub>4</sub>(Ph<sub>2</sub>BP<sub>2</sub>)]
(ASN = 5-azoniaspiro[4.4]nonane; M = Cr, Mo, W). The mononitriles
[ASN][<i>fac</i>-M(CO)<sub>3</sub>(RCN)(Ph<sub>2</sub>BP<sub>2</sub>)] (M = Cr, R = Me; M = Mo, R = Et; M = W, R = Et) are useful
reagents for the introduction of sulfur dioxide and isocyanides to
the π-basic M(CO)<sub>3</sub>(Ph<sub>2</sub>BP<sub>2</sub>)
fragment. While the fundamental coordination chemistry of this anionic
fragment mostly mirrors that of its conventional neutral cousins,
the electronic impact of Ph<sub>2</sub>BP<sub>2</sub> leads to divergent
reactivity in some cases. For example, the sulfur dioxide complexes
[ASN][<i>mer</i>-M(CO)<sub>3</sub>(SO<sub>2</sub>)(Ph<sub>2</sub>BP<sub>2</sub>)] (M = Mo, W) are unreactive toward CH<sub>2</sub>N<sub>2</sub>, dramatically different from the case for <i>mer</i>-M(CO)<sub>3</sub>(SO<sub>2</sub>)(L<sub>2</sub>) (L<sub>2</sub> = dppm, dppe, dppp). The spectral data of [ASN][Mo(CO)<sub>3</sub>(CNC<sub>6</sub>H<sub>4</sub>(2-NH<sub>2</sub>))(Ph<sub>2</sub>BP<sub>2</sub>)] and [ASN][Mo(CO)<sub>3</sub>(CNCH<sub>2</sub>CH<sub>2</sub>NH<sub>2</sub>)(Ph<sub>2</sub>BP<sub>2</sub>)], salts containing
the first anions of 2-aminophenyl isocyanide and 2-aminoethyl isocyanide,
respectively, indicate that the anionic M(CO)<sub>3</sub>(Ph<sub>2</sub>BP<sub>2</sub>) fragment may be more useful than neutral M(CO)<sub>3</sub>(dppe) for the π-back-bonding induced stabilization
of ligands prepared via template syntheses
