Spectral characteristics of products formed by reaction between Rhacac(PPh3)(CO) and methyl iodide

Iodomethane oxidative addition and CO migratory insertion in monocarbonylphosphine complexes of the type [Rh((C6H5)COCHCO((CH2)nCH3))(CO)(PPh3)]: Steric and electronic effects

“…Rh III -acyl complexes of the type of [Rh(b-diketonato)(COCH 3 )(PPh 3 )(I)] can be identified by the sharp resonance signal of the acyl COCH 3 -group at ca 3 ppm [20]. The 31 P NMR of the rhodium complexes gives a doublet with 1 J( 31 P-103 Rh) = ca 170 ppm for Rh I complexes, ca 120 ppm for Rh IIIalkyl complexes and ca 150 ppm for Rh III -acyl complexes [18,20,21]. Selected fragments of 1 H and 31 P NMR spectra, recorded during the oxidative addition of iodomethane to [Rh(bap)-(CO)(PPh 3 )] (7) in CDCl 3 , are given in Figs.…”

Reactivity of cationic methyl rhodium(III) complexes cis-[Rh(β-diket)(PPh3)2(CH3)(CH3CN)][BPh4] toward ligands of different character: pyridine, carbon monoxide, and triphenylphosphine

“…With this assumption, we studied the IR and NMR spectra of residues obtained by evaporation of dichloromethane solutions of 2 and 3 after 24 h storage. As expected, the IR spectra of these mixed products (in CH 2 Cl 2 ), alongside with acetyl m(CO) absorption bands of initial 2 and 3 at 1726 and 1728 cm À1 , contained m(CO) bands at 2060 and 2058 cm À1 , respectively, which are characteristic of terminal carbonyl ligands in rhodium(III) complexes [3,5,8,9,[11][12][13][14][15][16][17]27,28].…”

“…The 13 C NMR spectrum (in CDCl 3 ) of the mixed product obtained from complex 2 0 , along with signal from acetyl carbon, showed a doublet of triplets at d 186.2 ppm, 1 J(CRh) 61.9 Hz, 2 J(CP) 13.8 Hz, which is characteristic of carbonyl carbon in rhodium(III) bisphosphine complexes with two equivalent 31 P nuclei [13][14][15][16][17]28]. The 31 P{ 1 H} NMR spectrum of the mixed product obtained from 2, in addition to doublet from the initial acetyl complex, contained one more doublet of sharp lines at d 24.3 ppm, 1 J(PRh) 87.6 Hz (doublet of doublets with 2 J(PC) 13.8 Hz in the case of 2 0 ) that is in concordance with the above data and confirms the equivalence of two phosphine ligands in the isomerization product.…”

“…The 13 C NMR spectrum of a freshly prepared chloroform solution of 2 0 displays doublet of triplets from acetyl carbon at d 207.2 ppm, 1 J(CRh) 28.9 Hz, 2 J(CP) 6.2 Hz [13][14][15][16][17], split by spin-spin coupling with 103 Rh and two equivalent 31 P nuclei. The 31 P{ 1 H} NMR spectra of freshly prepared chloroform solutions of complexes 2 and 3 display in each case one sharp doublet at d 30.5 ppm, 1 J(PRh) 151.9 Hz (2) and at d 31.0 ppm, 1 J(PRh) 152.6 Hz (3).…”

“…On the basis of NMR spectra, we assign to the cation of 1 the following structure, akin to the structure of cation cis-[Rh(Acac)(PPh 3 ) 2 (CH 3 )(NH 3 )] + , which has been determined by NMR spectra and X-ray analysis [6]. The IR spectra of complexes 2 and 3 display intense bands with maxima at 1726 cm À1 (2) and 1728 cm À1 (3), which correspond to the m(CO) stretching vibration in the -C(@O)Me group of acetyl rhodium(III) complexes [3,5,[8][9][10][11][12][13][14][15][16][17].…”