15318-33-9Relevant academic research and scientific papers
Rhodium-Complex-Catalyzed Hydroformylation of Olefins with CO2and Hydrosilane
Ren, Xinyi,Zheng, Zhiyao,Zhang, Lei,Wang, Zheng,Xia, Chungu,Ding, Kuiling
supporting information, p. 310 - 313 (2016/12/30)
A rhodium-catalyzed one-pot hydroformylation of olefins with CO2, hydrosilane, and H2has been developed that affords the aldehydes in good chemoselectivities at low catalyst loading. Mechanistic studies indicate that the transformation is likely to proceed through a tandem sequence of poly(methylhydrosiloxane) (PMHS) mediated CO2reduction to CO and a conventional rhodium-catalyzed hydroformylation with CO/H2. The hydrosilylane-mediated reduction of CO2in preference to aldehydes was found to be crucial for the selective formation of aldehydes under the reaction conditions.
Slow exchange of bidentate ligands between rhodium(I) complexes: Evidence of both neutral and anionic ligand exchange
Chen, Si,Manoury, Eric,Poli, Rinaldo
, p. 5820 - 5826 (2015/02/19)
The phosphine double exchange process involving [RhCl(COD)(TPP)] and [Rh(acac)(CO)(TMOPP)] (TPP = PPh3, TMOPP = P(C6H4-4-OMe)3) to yield [RhCl(COD)(TMOPP)] and [Rh(acac)(CO)(TPP)] is very rapid but is followed by a much slower process where the bidentate ligands are exchanged to yield [Rh(acac)(COD)] and a mixture of [RhCl(CO)(TPP)2], [RhCl(CO)(TMOPP)2], and [RhCl(CO)(TPP)(TMOPP)]. The exchange involving [RhCl(COD)(L)] and [Rh(acac)(CO)(L)] yields [Rh(acac)(COD)] and [RhCl(CO)(L)2], where the reaction is much faster when L = TPP than when L = TMOPP. The mixed-metal system comprising [IrCl(COD)(TPP)] and [Rh(acac)(CO)(TPP)] yields all four complexes [M(acac)(COD)] and [MCl(CO)(TPP)2], where M = Rh and Ir. This illustrates that both a neutral ligand exchange and an anionic ligand exchange occur. Possible pathways for these processes are discussed.
Mixed anhydride complexes of rhodium(i) and ruthenium(ii)-their synthesis and ligand rearrangements
Coetzee, Jacorien,Eastham, Graham R.,Slawin, Alexandra M. Z.,Cole-Hamilton, David J.
, p. 3479 - 3491 (2014/03/21)
The coordination chemistry and solution behaviour of Rh(i) and Ru(ii) complexes derived from mixed anhydride ligands of carboxylic acids and phosphorus acids were explored. Similar to the free ligand systems, mixed anhydride complexes rearranged in solution via a number of pathways, with the pathway of choice dependent on the mixed anhydride employed, the auxiliary ligands present as well as the nature of the metal centre. Plausible mechanisms for some of the routes of rearrangement and by-product formation are proposed. Where stability allowed, new complexes were fully characterised, including solid state structures for four of the unrearranged mixed anhydride complexes and two of the interesting rearrangement products.
Modification of Wilkinson's catalyst with triphenyl phosphite: Synthesis, structure, 31P NMR and DFT study of trans-[RhCl(P(OPh) 3)(PPh3)2]
Choinopoulos, Ioannis,Papageorgiou, Ioannis,Coco, Silverio,Simandiras, Emmanuel,Koinis, Spyros
, p. 255 - 261 (2013/01/13)
The complex trans-[RhCl(P(OPh)3)(PPh3)2] (1) has been prepared and characterized by 31P NMR spectroscopy and single crystal X-ray crystallography. It was found that in the solid state there are two forms of complex 1 in the unit cell forming a cocrystal. DFT theoretical computations have confirmed the existence of the two forms and have provided evidence for the greater stability of 1 compared with Wilkinson's catalyst, [RhCl(PPh3)3] (2), in terms of the dissociation energy of the Rh-P(PPh3) bonds. On the basis of the phosphorus chemical shifts, δ P(PPh3), and the results of the theoretical computations, it is suggested that the Rh-P(PPh3) bonding interactions are slightly enhanced in 1 compared with 2. A distinct difference between complexes 1 and 2, was found to be the catalytic activity of 1 in the alkylation of allyl acetate with sodium diethylmalonate, while 2 is almost catalytically inefficient.
Rhodium-catalyzed cross-coupling reactions of carboxylate and organoboron compounds via chelation-assisted C-C bond activation
Wang, Jingjing,Liu, Bowen,Zhao, Haitao,Wang, Jianhui
, p. 8598 - 8607 (2013/02/23)
A new rhodium-catalyzed decarbonylated coupling reaction of ethyl benzo[h]quinoline-10-carboxylate and organoboron compounds that occurs through chelation-assisted sp2 C-COOEt bond activation was described. In this system CuCl played a very important role, and a five-membered rhodacycle was also involved as a key intermediate. Various functionalities were compatible in the reaction, and the desired products were obtained in good to excellent yields. DFT calculations on the mechanisms of this reaction using a Rh(I) model catalyst have also been carried out.
Efficient bulky phosphines for the selective telomerization of 1,3-butadiene with methanol
Tschan, Mathieu J.-L.,Garcia-Suarez, Eduardo J.,Freixa, Zoraida,Launay, Helene,Hagen, Henk,Benet-Buchholz, Jordi,Van Leeuwen, Piet W.N.M.
, p. 6463 - 6473 (2010/07/04)
A series of bulky phosphines containing substituted biphenyl, 2-methylnaphthyl, or 2,7-di-tert-butyl-9,9-dimethylxanthene moiety were prepared. They were used in the preparation of new monophosphine-palladium(0)- dvds complexes, which were employed as catalysts for the selective telomerization of 1,3-butadiene with methanol to obtain 1-methoxyocta-2,7-diene (1-MOD), the key intermediate in the Dow 1-octene process. Several ligands showed improved selectivity and yield compared to that of the benchmark ligand PPh3. Especially 2,7-di-tert-butyl-9,9-dimethylxanthen-4-yl- diphenylphosphine (4, mono-xantphos ) stands out as an excellent ligand in terms of yield, selectivity, and stability.
Synthesis of [RhCl(CO)(cyclopentadienone)]2 from [RhCl(cod)]2 and a 1,6-diyne under CO: Application to Rh(i)-catalyzed tandem [2+2+1] carbonylative cycloaddition of diynes and Claisen rearrangement
Lee, Sang Ick,Fukumoto, Yoshiya,Chatani, Naoto
, p. 3345 - 3347 (2010/07/20)
Although Rh(i)Cl(CO)(cpd) (cpd = cyclopentadienone) complexes were identified more than 40 years ago, their exact structures have not been determined because of the polymeric nature of these complexes. We determined the structure of [Rh(i)Cl(CO)(cpd)]2, which was formed by the reaction of [Rh(cod)Cl]2 with a 1,6-diyne under CO. In addition, based on determination of the structure of the [Rh(i)Cl(CO)(cpd)]2 complex, we identified a new catalytic tandem reaction - the Rh-catalyzed [2+2+1] carbonylative cycloaddition of phenoxide-substituted diynes and Claisen rearrangement.
Sterically demanding, sulfonated, triarylphosphines: Application to palladium-catalyzed cross-coupling, steric and electronic properties, and coordination chemistry
Moore, Lucas R.,Western, Elizabeth C.,Craciun, Raluca,Spruell, Jason M.,Dixon, David A.,O'Halloran, Kevin P.,Shaughnessy, Kevin H.
, p. 576 - 593 (2009/01/31)
Tri(2,4-dimethyl-5-sulfonatophenyl)phosphine trisodium (TXPTS ·Na3) and tri(4-methoxy-2-methyl5-sulfonatophenyl)phosphine trisodium (TMAPTS·Na3) both provide more active catalysts for Suzuki and Sonogashira couplings of aryl bromides in aqueous solvents than tri(3-sulfonatophenyl)phosphine trisodium (TPPTS ·Na3). In the Heck coupling, TXPTS ·Na3 provides the most effective catalyst system. Cone angles determined from DFT-optimized structures show that both TXPTS·Na3 (206°) and TMAPTS·Na3 (208°) are significantly larger than TPPTS·Na3 (165°). The identity of the counterion had a significant effect on the calculated cone angles for these ligands. The electronic properties of these ligands determined by the CO stretching frequencies of trans-RhL2(Cl)CO complexes were identical, although calculated electronic parameters suggest subtle differences between these ligands. Similar to TPPTS·Na3, both TXPTS·Na3 and TMAPTS·Na3 react with Pd(OAc)2 in aqueous solvents to give LnPd0 complexes and the corresponding phosphine oxide. The reduction of palladium(II) by TXPTS·Na3 is significantly slower than is seen with TMAPTS·Na3 or TPPTS·Na3 at room temperature. Evidence of palladacycle complexes derived from TXPTS·Na3 and TMAPTS·Na3 by activation of an ortho-methyl substituent was also observed in ligand coordination studies and under catalytic reaction conditions.
Remarks on the process of homogeneous carbonylation of rhodium compounds by N,N-dimethylformamide
Varshavsky, Yuri S.,Cherkasova, Tatiana G.
, p. 887 - 893 (2007/10/03)
Reductive carbonylation of rhodium(III) chloride complexes, commercial RhCl3 · nH2O neutralized with BaCO3, (Me2NH2)2[RhCl5(DMF)], (PPh4)[RhCl4(H2/sub
Formation of a phosphine-phosphinite ligand in RhCl(PRR′2) [P,P-R′(R)POCH2P(CH2OH)2] and R′H from cis-RhCl(PRR′2)2[P(CH2OH) 3] via P-C bond cleavage
Lorenzini, Fabio,Patrick, Brian O.,James, Brian R.
, p. 8998 - 9002 (2008/10/09)
Reaction of RhCl(1,5-cod)(THP), where THP = P(CH2OH) 3, with several PRR′2 phosphines (R = or ≠ R′) generates, concomitantly with R′H, the derivatives RhCl(PRR′2)[P,P-R′(R)POCH2P(CH 2OH)2] in two isomeric forms. The hydrogen of the hydrocarbon co-product derives from a THP hydroxyl group which becomes an 'alkoxy' group at the residual PRR' moiety, this resulting in the P,P-chelated R′(R)POCH2P(CH2OH)2 ligand. One of the isomers of the PPh3 system, cis-RhCl(PPh3)[P, P-P(Ph) 2OCH2P(CH2OH)2], was structurally characterized (cis refers to the disposition of the P atoms with Ph substituents).
