79190-90-2Relevant academic research and scientific papers
Spectroscopic and reactivity differences in metal complexes derived from sulfur containing Triphos homologs
Petuker,Gerschel,Piontek,Ritterskamp,Wittkamp,Iffland,Miller,Van Gastel,Apfel
, p. 13251 - 13262 (2017/10/16)
Herein, we report a simplified method for the synthesis of Triphos homologs H3CC(CH2X)n(CH2Y)3-n (X = SPh, Y = PPh2, n = 0-3). The multidentate compounds were tested for their potential to coordinate metals such as Ni, Fe, and Mo under the same experimental conditions. Cyclic voltammetry, spectroelectrochemical IR investigations as well as DFT calculations were used to examine the electronic alterations in a series of [{H3CC(CH2X)n(CH2Y)3-n}Mo(CO)3] complexes and to evaluate their potential to open coordination sites or to release CO upon oxidation or in the presence of different solvents. In addition, we demonstrate that the catalytic hydrosilylation of N,N-dimethylbenzamide to N,N-dimethylbenzylamine is influenced by the applied tripodal ligand. Our investigations show the high potential of such manipulations to selectively alter the dynamics of the binding properties of Triphos-metal complexes and their reactivity.
Photochemically generated transients from κ2- and κ3-Triphos derivatives of group 6 metal carbonyls and their reactivity with olefins
Kyran, Samuel J.,Muhammad, Sohail,Knestrick, Matthew,Bengali, Ashfaq A.,Darensbourg, Donald J.
, p. 3163 - 3170 (2012/06/04)
The synthesis and characterization of (κ2-Triphos)M(CO) 4 derivatives, where M = Mo, W and Triphos = MeC(CH 2PPh2)3, are reported. Photolyses of these metal carbonyls in dichloromethane or CO2-saturated dichloromethane readily afford the (κ3-Triphos)M(CO)3 complexes with no evidence of significant solvent or carbon dioxide interactions with the site vacated by CO. However, in the presence of 1-hexene a transient (κ2-Triphos)M(CO)3(1-hexene) adduct was observed, which subsequently releases the olefin with formation of the stable κ3-tricarbonyl species. In the case of M = W the kinetic parameters for this process were assessed, with the rate of olefin replacement being inversely proportional to [1-hexene]. A dissociative rate constant of 25.6 ± 1.1 s-1 at 298 K was determined for olefin loss, with the selectivity for 1-hexene vs free phosphine arm addition to the unsaturated intermediate being somewhat surprisingly large at 22. The activation parameters measured were δH? = 26.1 ± 0.4 kcal/mol and δS? = 36 ± 3 eu, which are consistent with a dissociative substitution reaction. The kinetic parameters for this transformation were unaffected in the presence of excess quantities of CO 2. Although no interaction of CO2 with the transient species resulting from CO loss in the κ2 complex was noted on the time scale of 50 ms, an intermediate described as an η2- HSiEt3 complex was observed upon addition of triethylsilane. This latter transient species underwent dissociation with κ3-complex formation about 15 times as fast as its 1-hexene analogue. X-ray structures of the κ2 complexes of Mo and W where the dangling phosphine arm has undergone oxidation are also reported.
Molybdenum and tungsten complexes of the neutral tripod ligands HC(pz)3 and MeC(CH2PPh2)3
Dilsky, Stefan
, p. 2887 - 2896 (2008/02/02)
Starting from [M(CO)6], seven-coordinated complexes of tungsten and molybdenum containing the facially coordinating ligands HC(pz)3 (1) and MeC(CH2PPh2)3 (2) were obtained in a two-step reaction seque
Chirale Tripodliganden: Die Eintopfreaktion MeC(CH2PPh2)3 MeC(CH2P(Ph)(R))3; Zwischenstufen, diastereoselektive Kontrolle und Komplexchemie
Walter, Olaf,Klein, Thomas,Huttner, Gottfried,Zsolnai, Laszlo
, p. 63 - 82 (2007/10/02)
The tripod ligand H3CC(CH2PPh2)3, 1, reacts with lithium metal to produce H3CC(CH2PPhLi)3, 2, in good yields.Compound 2 crystallizes in the form of 2*4THF*MeN(CH2CH2NMe2)2.The crystal structure of this adduct shows bridging as well as terminal phosphorous-coordination of lithium.Compound 2 reacts with electrophiles RX to give H3CC(CH2P(Ph)(R))3, 3 (R = H, Me, Et, iPr, CH2Ph, 3a-e).The transformation 1 2 3 can be performed in a one-pot reaction.While the chiral compounds 3 may be characterized as such, their reaction with (CH3CN)3Mo(CO)3 yields theeasy-to-characterize coordination compounds H3CC(CH3P(Ph)(R))3Mo(CO)3, 5.NMR analysis of 3 and 5 shows that from the two diastereomeric forms of 3 (the enantiomeric pair SSR/RRS and the pair SSS/RRR) only the SSR/RRS-diastereomer is formed with R = CH2Ph (3e, 5e).In the other cases (R = H, Me, Et, iPr) a statistical 3:1 mixture of the two diastereomers is formed.These findings are further corroborated by X-ray analyses of H3CC(CH2P(Ph)(Et))3Mo(CO)3, 5c, and H3CC(CH2P(Ph)(CH2Ph))3Mo(CO)3, 5e.The remarkable facts reported in this paper are the ease with which the chiral tripod ligands H3CC(CH2P(Ph)(R))3, 3, are prepared, and the evidence that their formation may well involve diastereoselective control.
Uebergangsmetall-Silyl-Komplexe. XXXVIII. Darstellung Phosphan-substituierter Hydrido-Silyl-Komplexe des Chrom, Molybdaen und Wolfram, (CO)5-n(R'3P)nM(H)SiR3 (n = 2, 3) und Bildung der Hydrido-Chloro-Komplexe (CO)3(L-L)M(H)Cl durch Umsetzung von (CO)3(L-L)M(NCR') mit HSiClR2
Piana, Hermann,Schubert, Ulrich
, p. 303 - 323 (2007/10/02)
At least two phosphorus atoms at the metal (n2) are necessary to obtain stable hydrido-silyl complexes of the type (CO)5-n(R'3P)nM(H)SiR3 (M = Cr, Mo, W).The complexes (CO)3(dppe)M(H)SiR3 and (CO)2(tdppme)M(H)SiR3 are obtained either by photochemical reaction of (CO)4(dppe)M or (CO)3(tdppme)M, or by thermal reaction of (CO)4(dppe)M(THF) with silanes HSiR3.Reaction of the isonitrile complexes (CO)3(L-L)M(NCR') (M = Mo, W; L-L = tmeda, bipy, dppe, (PPh3)2) with silanes HSiR2Cl does not yield hydrido-silyl complexes, but instead the hydrido-chloro complexes (CO)3(L-L)M(H)Cl.The latter complexes were also prepared by reaction of (CO)3(L-L)M(NCR') with HCl for comparison.The molecular structure of (CO)3(dppe)W(H)Cl was determined by an X-ray structure analysis.The complex has a capped-octahedral geometry with a facial arrangement of the three CO ligands and the hydride ligand above the triangular face formed by the two phosphorus atoms and a CO ligand.
Piana, Hermann,Schubert, Ulrich
, p. 303 - 323 (2007/10/02)
At least two phosphorus atoms at the metal (n2) are necessary to obtain stable hydrido-silyl complexes of the type (CO)5-n(R'3P)nM(H)SiR3 (M = Cr, Mo, W).The complexes (CO)3(dppe)M(H)SiR3 and (CO)2(tdppme)M(H)SiR3 are obtained either by photochemical reaction of (CO)4(dppe)M or (CO)3(tdppme)M, or by thermal reaction of (CO)4(dppe)M(THF) with silanes HSiR3.Reaction of the isonitrile complexes (CO)3(L-L)M(NCR') (M = Mo, W; L-L = tmeda, bipy, dppe, (PPh3)2) with silanes HSiR2Cl does not yield hydrido-silyl complexes, but instead the hydrido-chloro complexes (CO)3(L-L)M(H)Cl.The latter complexes were also prepared by reaction of (CO)3(L-L)M(NCR') with HCl for comparison.The molecular structure of (CO)3(dppe)W(H)Cl was determined by an X-ray structure analysis.The complex has a capped-octahedral geometry with a facial arrangement of the three CO ligands and the hydride ligand above the triangular face formed by the two phosphorus atoms and a CO ligand.
