Abstract:Asymmetric complexes of rhodium(I) with a monothio-/3-diketonate ligand and one of the chelating diolefins norbornadiene, cycloocta-1,5-diene, cyclooctatetraene, duroquinone, or 2,5-di-ieri-butyl-£-benzoquinone have been synthesized and studied by pmr spectroscopy. The compounds show thermally induced intramolecular proton exchange between nonequivalent sites at different rates depending upon the diolefin. In the presence of dimethyl sulfoxide or triphenylarsine the exchange is accelerated. The rate is first o… Show more
“…The resulting five-coordinate intermediate exchange of H(12 a ) and H(12 b ) may now occur via Berry-type pseudorotational processes. In this respect, it is interesting that slight amounts of Cl - or acetone may also enhance the alkene site-exchange rates of complex 2 , probably via five-coordinate intermediates. − However, intermediates with monodentate ligands are also possible in the light of mounting evidence for N−N ligands. ,, 8 Mechanism for Exchange of the Four N-Atoms in 10 …”
Section: Discussionmentioning
confidence: 99%
“…In this respect, it is interesting that slight amounts of Cl -or acetone may also enhance the alkene site-exchange rates of complex 2, probably via five-coordinate intermediates. [26][27][28][29][30] However, intermediates with monodentate ligands are also possible in the light of mounting evidence for N-N ligands. 24,25,31 When we increase the temperature, intermolecular ligand exchange becomes feasible, but at lower rates than the previous process.…”
Section: Synthesis and Characterization Of [Rhcl(26-(c(h)dn-rmentioning
Reactions of [RhCl(diene)]2 (diene=NBD,COD) with bi-and terdentate nitrogen ligands. X-ray structures of five-coordinate complexes Haarman, H.F.; Bregman, F.R.; Ernsting, J.M.; Veldman, N.; Spek, A.L.; Vrieze, K.
Published in: Organometallics
DOI:10.1021/om960760bLink to publication
Citation for published version (APA):Haarman, H. F., Bregman, F. R., Ernsting, J. M., Veldman, N., Spek, A. L., & Vrieze, K. (1997). Reactions of [RhCl(diene)]2 (diene=NBD,COD) with bi-and terdentate nitrogen ligands. X-ray structures of five-coordinate complexes. Organometallics, 16, 54-67. DOI: 10.1021/om960760b General rights It is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons).
Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Reaction of [RhCl(diene)] 2 (diene ) 1,5-cyclooctadiene (COD) or bicyclo[2.2.1] hepta-2,5-diene (NBD)) with the N-N-N nitrogen ligands 2,6-(C(R 1 )dN-R 2 ) 2 C 5 H 3 N in CD 2 Cl 2 or CH 2 Cl 2 yielded the five-coordinate complexes [RhCl(2,6-(C(H)dN-R 2 ) 2 C 5 H 3 N)(diene)] (diene ) NBD; R 2 ) i- Pr, t-Bu, and p-anisyl), which has been isolated for NBD but not for COD. A single-crystal X-ray determination showed that [RhCl(2,6-(C(H)dN-p-anisyl) 2 C 5 H 3 N)(NBD)] has a distorted trigonal bipyramidal configuration with the pyridyl N-atom, one imine N-atom, and one alkene double bond in the equatorial plane, while the second alkene bond and the chloride atom occupy the axial positions. This conformation containing one noncoordinated imine moiety is clearly retained at 183 K in CD 2 Cl 2 , as is also the case for the other complexes. For the COD complexes, the reaction is more complicated, as the intermediates that are observed depend on the substituents R 1 and R 2 of the N-N-N nitrogen ligand. The five-coordinate complexes [RhCl(2,6-(C(R 1 )dN-R 2 ) 2 C 5 H 3 N)(COD)] could be observed at low temperatures for R
IntroductionRecently we reported novel Rh(I) complexes which were able to cleave C-Cl bonds of reagents such as dichloromethane, chloroform, benzyl chloride, and R,Rdichlorotoluene by oxidative addition. 1 By employment of N-N-N nitrogen ligands of the type 2,6-(C(R 1 )dN-R 2 ) 2 C 5 H 3 N (R 1 ) H, R 2 ) i-Pr, t-Bu, cyclohexyl, and p-anisyl; R 1 ) Me, R 2 ) p-anisyl and i-Pr), we succeeded in preparing very nucleophilic and very reactive Rh(I) complexes via reaction of [RhCl(alkene) 2 ] 2 (alkene ) cyclooctene or...
“…The resulting five-coordinate intermediate exchange of H(12 a ) and H(12 b ) may now occur via Berry-type pseudorotational processes. In this respect, it is interesting that slight amounts of Cl - or acetone may also enhance the alkene site-exchange rates of complex 2 , probably via five-coordinate intermediates. − However, intermediates with monodentate ligands are also possible in the light of mounting evidence for N−N ligands. ,, 8 Mechanism for Exchange of the Four N-Atoms in 10 …”
Section: Discussionmentioning
confidence: 99%
“…In this respect, it is interesting that slight amounts of Cl -or acetone may also enhance the alkene site-exchange rates of complex 2, probably via five-coordinate intermediates. [26][27][28][29][30] However, intermediates with monodentate ligands are also possible in the light of mounting evidence for N-N ligands. 24,25,31 When we increase the temperature, intermolecular ligand exchange becomes feasible, but at lower rates than the previous process.…”
Section: Synthesis and Characterization Of [Rhcl(26-(c(h)dn-rmentioning
Reactions of [RhCl(diene)]2 (diene=NBD,COD) with bi-and terdentate nitrogen ligands. X-ray structures of five-coordinate complexes Haarman, H.F.; Bregman, F.R.; Ernsting, J.M.; Veldman, N.; Spek, A.L.; Vrieze, K.
Published in: Organometallics
DOI:10.1021/om960760bLink to publication
Citation for published version (APA):Haarman, H. F., Bregman, F. R., Ernsting, J. M., Veldman, N., Spek, A. L., & Vrieze, K. (1997). Reactions of [RhCl(diene)]2 (diene=NBD,COD) with bi-and terdentate nitrogen ligands. X-ray structures of five-coordinate complexes. Organometallics, 16, 54-67. DOI: 10.1021/om960760b General rights It is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons).
Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Reaction of [RhCl(diene)] 2 (diene ) 1,5-cyclooctadiene (COD) or bicyclo[2.2.1] hepta-2,5-diene (NBD)) with the N-N-N nitrogen ligands 2,6-(C(R 1 )dN-R 2 ) 2 C 5 H 3 N in CD 2 Cl 2 or CH 2 Cl 2 yielded the five-coordinate complexes [RhCl(2,6-(C(H)dN-R 2 ) 2 C 5 H 3 N)(diene)] (diene ) NBD; R 2 ) i- Pr, t-Bu, and p-anisyl), which has been isolated for NBD but not for COD. A single-crystal X-ray determination showed that [RhCl(2,6-(C(H)dN-p-anisyl) 2 C 5 H 3 N)(NBD)] has a distorted trigonal bipyramidal configuration with the pyridyl N-atom, one imine N-atom, and one alkene double bond in the equatorial plane, while the second alkene bond and the chloride atom occupy the axial positions. This conformation containing one noncoordinated imine moiety is clearly retained at 183 K in CD 2 Cl 2 , as is also the case for the other complexes. For the COD complexes, the reaction is more complicated, as the intermediates that are observed depend on the substituents R 1 and R 2 of the N-N-N nitrogen ligand. The five-coordinate complexes [RhCl(2,6-(C(R 1 )dN-R 2 ) 2 C 5 H 3 N)(COD)] could be observed at low temperatures for R
IntroductionRecently we reported novel Rh(I) complexes which were able to cleave C-Cl bonds of reagents such as dichloromethane, chloroform, benzyl chloride, and R,Rdichlorotoluene by oxidative addition. 1 By employment of N-N-N nitrogen ligands of the type 2,6-(C(R 1 )dN-R 2 ) 2 C 5 H 3 N (R 1 ) H, R 2 ) i-Pr, t-Bu, cyclohexyl, and p-anisyl; R 1 ) Me, R 2 ) p-anisyl and i-Pr), we succeeded in preparing very nucleophilic and very reactive Rh(I) complexes via reaction of [RhCl(alkene) 2 ] 2 (alkene ) cyclooctene or...
“…NOESY spectrum of 1 in CDCl 3 at 273 Kbeen shown that the exchange rate in noncoordinating solvents is increased by the presence of traces of Cl Ϫ anions, or by adventitious acetone. [7,9,10] Figure 2. 19 F NMR spectra of 2 in [D 6 ]acetone at different temperatures.…”
Keywords: Alkenes / Hydrogenations / N ligands / Phosphanes / RhodiumThe reaction of [Rh 2 (µ-Cl) 2 (COD) 2 ] (COD = 1,5-cyclooctadiene) or [Rh 2 (µ-Cl) 2 (TFB) 2 ] (TFB = tetrafluorobenzobicyclo[2.2.2]octatriene) with the N-donor chelating ligand OP-Py 2 Ph (Py = 2-pyridyl) in the presence of TlBF 4 affords cationic complexes [Rh(diene)(OPPy 2 Ph)](BF 4 ) (1, diene: COD; 2, diene: TFB). Compounds 1 or 2 react with CO to give [Rh(CO) 2 (OPPy 2 Ph)](BF 4 ) (4), which is also obtained by treatment of [Rh 2 (µ-Cl) 2 (CO) 4 ] with OPPy 2 Ph and TlBF 4 . In a similar way, the complexes [Rh(diene)(OPPy 3 )](BF 4 ) (5, diene: COD; 6, diene: TFB) are obtained when using OPPy 3 ; they react with CO to give [Rh 2 (µ-CO) 3 (OPPy 3 ) 2 ](BF 4 ) 2 (9). The [a] 289 behavior of the complexes in solution is reported. The complexes with OPPy 3 , 5 and 6, show equivalence of the three Py groups in their NMR spectra. Complex 5 is square-planar in the solid state, and in solution, and the uncoordinated and coordinated Py groups undergo fast exchange in solution. Complex 6 is pentacoordinated in the solid state and in solution, and its Py groups exchange their coordination sites in a fast topomerization process. The single-crystal X-ray structures of 5 and 6 have been solved. The behavior of 1 and 5 as catalysts in hydrogenation reactions of cyclohexene, acetone, and cyclohexanone is also reported.
“…A number of four-coordinate square-planar diolefin complexes of rhodium(I) exhibit temperature-dependent *H NMR spectra which have been interpreted in terms of an intramolecular exchange of olefin protons between nonequivalent sites.1,2 The rate of this site exchange is enhanced by the addition of donor ligands such as organophosphines, organoarsines, dimethyl sulfoxide, and pyridine. An associative-dissociative mechanism involving (i) formation of a five-coordinate 1:1 adduct from a square-planar complex and base (eq 1) and (ii) an intramolecular rearrangement of the five-coordinate adduct (eq 2) provides a rationalization of the reported data.2…”
Section: Introductionmentioning
confidence: 62%
“…Reaction of 3 (0.90 g) with Tl(hfac) (1.10 g) in dichloromethane for */2 h, followed by filtration and evaporation to dryness, gave an oily residue. Extraction with pentane and evaporation to dryness gave Rh(hfac)(C7H6(C02Me)2) (1) as an orange oil (1.17 g, 87%), which slowly solidified on standing. Pyridine (0.18 g) was added to a solution of 1 (1.17 g) in pentane (10 ml).…”
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
