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(CH2CHCH2)2}] and diax-[Re2(CO)8(PPh3){κ1(P)-p-MeOC6H4P(CH2CHCH2)2}]

• Published in: Inorganica Chimica Acta 2016-01, Vol.439, p.178-185
• Main Authors: Peña, Deisy, Otero, Yomaira, Arce, Alejandro, García, Juan M., Coll, David S., Ocando-Mavarez, Edgar, Machado, Rubén, González, Teresa
• Format: Article
• Language: English
• Subjects: Diallylphosphines; Dinuclear rhenium; Dirhenium carbonyls; Hemilability; Isomerism
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/j.ica.2015.10.013

Reaction of [Re2(CO)8{μ:κ3(P,C,C)-p-MeOC6H4P(CH2CHCH2)2}] (6) with nucleophile molecules, such as CO and PPh3, demonstrates that the diallylphosphine can indeed act as hemilabile ligand in the rhenium dinuclear complex, while [Re2(CO)8{μ:κ3(P,C,C)-iPr2NP(CH2CHCH2)2}] (4) does not react in presence of nucleophiles. [Display omitted] •Cyanoethylphosphines afford mono- and disubstituted dirhenium carbonyl complexes.•Diallylphosphines undergo a μ:κ3(P,C,C)-coordination in dirhenium carbonyl complexes.•Cleavage of the allyl π-coordination is observed by reaction with CO and PPh3.•Photolysis of dirhenium carbonyl complexes leads to mononuclear derivatives.•Diallylphosphines can act as hemilabile ligands in dirhenium carbonyl complexes. The reaction of [Re2(CO)8(MeCN)2] 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 [Re2(CO)8{μ:κ3(P,C,C)-p-MeOC6H4P(CH2CHCH2)2}] (6) reacts with nucleophiles, such as CO and PPh3. In contrast, the compound [Re2(CO)8{μ:κ3(P,C,C)-iPr2NP(CH2CHCH2)2}] (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 [Re2(CO)9{κ1(P)-p-MeOC6H4P(CH2CHCH2)2}] (5) and diax-[Re2(CO)8(PPh3){κ1(P)-p-MeOC6H4P(CH2CHCH2)2}] (8) in dichloromethane at room temperature undergoes to rhenium–rhenium bond cleavage to give mononuclear derivatives.