Cyclooctadiene iridium complexes with phosphine and pentadienyl ligands

Publication date: Available online 15 February 2019Source: Journal of Organometallic ChemistryAuthor(s): Amira Reyna Madrigal, Naytzé Ortiz-Pastrana, M. Angeles Paz-SandovalAbstractReaction of [(η4-COD)Ir(μ2-Cl)]2 (1) with tin CH2CRCHCRCH2SnR′3 (R = H, Me; R' = Me, n-Bu) or lithium pentadienide reagents gives the corresponding acyclic pentadienyl sandwich compounds [(η4-COD)Ir(η5-CH2CMeCHCMeCH2) (2) and [(η4-COD)Ir(η5-CH2CHCHCHCH2) (3). Treatment of 1 with different phosphines affords the well-known mononuclear phosphine complexes [(η4-COD)IrClPR3] [R = Ph, 4; i-Pr, 5; Me, 6] which react with lithium pentadienide to give the exclusive formation of [(η4-COD)Ir(1-3-η-CH2CHCHCHCH2)PR3] [R = Ph, 7; P(i-Pr), 8], whereas the less steric trimethylphosphine shows an equilibrium mixture of the pseudo iridacyclic [(η4-COD)Ir(1,4-5′-η-CH2CHCHCHCH2)PMe3] (9a) and [(η4-COD)Ir(1-3-η-CH2CHCHCHCH2)PMe3] (9b) in a 2:1 ratio. Additionally, the addition reaction of phosphines to compound 2 gives the dimethyl-pentadienyl complexes [(η4-COD)Ir(1-3-η-CH2CMeCHCMeCH2)PPh3] (10) and the mixture of isomers [(η4-COD)Ir(1,4-5′-η-CH2CMeCHCMeCH2)PMe3] (11a) and [(η4-COD)Ir(1-3-η-CH2CMeCHCMeCH2)PMe3] (11b) in a 2:1 ratio. Compounds 2, 4, 5, 6, 7, 8, 9b, 10 and 11a have been structurally characterized by single-crystal X-ray diffraction studies. The influence of the electronic and steric effects of the different ligands, as well as the preference of the bonding mode...

Source: Journal of Organometallic Chemistry - February 16, 2019 Category: Chemistry Source Type: research