Synthesis, characterization and reactivity of dinuclear rhenium complexes containing hemilabile phosphines as ligands: X-ray structures of diax-[Re2(CO)8{κ1(P)-Ph2P(CH2)2CN}2], [Re2(CO)8{μ:κ3(P,C,C)-iPr2NP(CH2CH=CH2)2}] and diax-[Re2(CO)8(PPh3){κ1(P)-p-MeOC6H4P(CH2CH=CH2)2}]

Abstract:

The reaction of [Re<inf>2</inf>(CO)<inf>8</inf>(MeCN)<inf>2</inf>] with cyanoethylphosphines affords mono- and disubstituted compounds where the phosphine ligand is κ¹(P)-coordinated. When diallylphosphines are used as ligands, the μ:κ³(P,C,C)-coordination through the phosphorus atom and an allyl fragment is observed. The hemilabile behavior of the diallyl(p-methoxyphenyl)phosphine ligand was confirmed via the cleavage of the allyl π-coordination when [Re<inf>2</inf>(CO)<inf>8</inf>{μ:κ³(P,C,C)-p-MeOC<inf>6</inf>H<inf>4</inf>P(CH<inf>2</inf>CH=CH<inf>2</inf>)<inf>2</inf>}] (6) reacts with nucleophiles, such as CO and PPh<inf>3</inf>. In contrast, the compound [Re<inf>2</inf>(CO)<inf>8</inf>{μ:κ³(P,C,C)-ⁱPr<inf>2</inf>NP(CH<inf>2</inf>CH=CH<inf>2</inf>)<inf>2</inf>}] (4) does not react in the presence of nucleophiles, suggesting that the metal-allyl π-bonding interaction is stronger for diallyldiisopropylaminophosphine than diallyl(p-methoxyphenyl)phosphine ligand. Furthermore, photolysis of [Re<inf>2</inf>(CO)<inf>9</inf>{κ¹(P)-p-MeOC<inf>6</inf>H<inf>4</inf>P(CH<inf>2</inf>CH=CH<inf>2</inf>)<inf>2</inf>}] (5) and diax-[Re<inf>2</inf>(CO)<inf>8</inf>(PPh<inf>3</inf>){κ¹(P)-p-MeOC<inf>6</inf>H<inf>4</inf>P(CH<inf>2</inf>CH=CH<inf>2</inf>)<inf>2</inf>}] (8) in dichloromethane at room temperature undergoes to rhenium-rhenium bond cleavage to give mononuclear derivatives.

Año de publicación:

2016

Keywords:

• Hemilability
• Dirhenium carbonyls
• Diallylphosphines
• Isomerism
• Dinuclear rhenium

Fuente:

scopus