2999-74-8Relevant articles and documents
Synthesis and Characterization of Atomically Flat Methyl-Terminated Ge(111) Surfaces
Wong, Keith T.,Kim, Youn-Geun,Soriaga, Manuel P.,Brunschwig, Bruce S.,Lewis, Nathan S.
, p. 9006 - 9014 (2015)
Atomically flat, terraced H-Ge(111) was prepared by annealing in H2(g) at 850 °C. The formation of monohydride Ge-H bonds oriented normal to the surface was indicated by angle-dependent Fourier-transform infrared (FTIR) spectroscopy. Subsequent
Synthesis and characterisation of magnesium methyl complexes with monoanionic chelating nitrogen donor ligands and their reaction with dioxygen
Bailey, Philip J.,Dick, Caroline M. E.,Fahre, Sylvie,Parsons, Simon
, p. 1655 - 1661 (2000)
Treatment of the Grignard reagent MeMgCl with the lithiates Li[L-X] (Li[L-X] = lithium ss-diketiminate [HC{C(Me)=NAr'}2Li] (Ar' =: 2,6-diisopropyIphenyl or lithium W.W-diisopropylaminotroponiminate, Li[('Pr2)ATI] in THF provided four-co-ordinate methylmag
Synthesis, characterization and Schlenk equilibrium studies of methylmagnesium compounds with O- and N-donor ligands - The unexpected behavior of [MgMeBr(pmdta)] (pmdta = N,N,N′,N″,N″- pentamethyldiethylenetriamine)
Yousef, Rushdi I.,Walfort, Bernhard,Rüffer, Tobias,Wagner, Christoph,Schmidt, Harry,Herzog, Renate,Steinborn, Dirk
, p. 1178 - 1191 (2005)
MgMe2 (1) was found to react with 1,4-diazabicyclo[2.2.2]octane (dabco) in tetrahydrofuran (thf) yielding a binuclear complex [{MgMe 2(thf)}2(μ-dabco)] (2). Furthermore, from reactions of MgMeBr with diglyme (diethylene glycol dimethyl ether), NEt3, and tmeda (N,N,N′,N′-tetramethylethylenediamine) in etheral solvents compounds MgMeBr(L), (L = diglyme (5); NEt3 (6); tmeda (7)) were obtained as highly air- and moisture-sensitive white powders. From a thf solution of 7 crystals of [MgMeBr(thf)(tmeda)] (8) were obtained. Reactions of MgMeBr with pmdta (N,N,N′,N″,N″-pentamethyldiethylenetriamine) in thf resulted in formation of [MgMeBr(pmdta)] (9) in nearly quantitative yield. On the other hand, the same reaction in diethyl ether gave MgMeBr(pmdta)·MgBr2(pmdta) (10) and [{MgMe2(pmdta)} 7{MgMeBr(pmdta)}] (11) in 24% and 2% yield, respectively, as well as [MgMe2(pmdta)] (12) as colorless needle-like crystals in about 26% yield. The synthesized methylmagnesium compounds were characterized by microanalysis and 1H and 13C NMR spectroscopy. The coordination-induced shifts of the 1H and 13C nuclei of the ligands are small; the largest ones were found in the tmeda and pmdta complexes. Single-crystal X-ray diffraction analyses revealed in 2 a tetrahedral environment of the Mg atoms with a bridging dabco ligand and in 8 a trigonal-bipyramidal coordination of the Mg atom. The single-crystal X-ray diffraction analyses of [MgMe2(pmdta)] (12) and [MgBr 2(pmdta)] (13) showed them to be monomeric with five-coordinate Mg atoms. The square-pyramidal coordination polyhedra are built up of three N and two C atoms in 12 and three N and two Br atoms in 13. The apical positions are occupied by methyl and bromo ligands, respectively. Temperature-dependent 1H NMR spectroscopic measurements (from 27 to -80°C) of methylmagnesium bromide complexes MgMeBr(L) (L = thf (4); diglyme (5); NEt 3 (6); tmeda (7)) in thf-d8 solutions indicated that the deeper the temperature the more the Schlenk equilibria are shifted to the dimethylmagnesium/dibromomagnesium species. Furthermore, at -80°C the dimethylmagnesium compounds are predominant in the solutions of Grignard compounds 4-6 whereas in the case of the tmeda complex7 the equilibrium constant was roughly estimated to be 0.25. In contrast, [MgMeBr(pmdta)] (9) in thf-d8 revealed no dismutation into [MgMe2(pmdta)] (12) and [MgBr2(pmdta)] (13) even up to -100°C. In accordance with this unexpected behavior, 1:1 mixtures of 12 and 13 were found to react in thf at room temperature yielding quantitatively the corresponding Grignard compound 9. Moreover, the structures of [MgMeBr(pmdta)] (9c), [MgMe2(pmdta)] (12c), and [MgBr2(pmdta)] (13c) were calculated on the DFT level of theory. The calculated structures 12c and 13c are in a good agreement with the experimentally observed structures 12 and 13. The equilibrium constant of the Schlenk equilibrium (2 9c ? 12c + 13c) was calculated to be K gas = 2.0 × 10-3 (298 K) in the gas phase. Considering the solvent effects of both thf and diethyl ether using a polarized continuum model (PCM) the corresponding equilibrium constants were calculated to be Kthf = 1.2 × 10-3 and Kether = 3.2 × 10-3 (298 K), respectively.
Magnesium Stung by Nonclassical Scorpionate Ligands: Synthesis and Cone-Angle Calculations
Stuhl, Christoph,Maichle-M?ssmer, C?cilia,Anwander, Reiner
, p. 14254 - 14268 (2018/09/20)
A series of tris(pyrazolyl)alkane (RCTp) scorpionate ligands of the type RCTp3-R′ (R=Me, nBu, SiMe3; R′=H, Me, Ph, iPr, tBu) were synthesized and their ability to coordinate methylmagnesium moieties was examined. The reaction of Mg(AlMe4)2 with neutral proligands HCTp3-Ph or Me3SiCTp3-Me, containing a non-innocent backbone methine moiety, led to deprotonation/rearrangement and SiMe3/AlMe3 exchange to afford [(Me3AlCTp3-Ph)2Mg] and [(Me3AlCTp3-Me)Mg(AlMe4)], respectively, with monoanionic tripodal ligands. Treatment of sterically less demanding RCTp3-R′ with Mg(AlMe4)2 produced isostructural dicationic “metal-in-a-box” complexes of the type [(RCTp3-R′)2Mg][AlMe4]2 (R=Me, nBu; R′=H, Me). Utilization of the superbulky ligands MeCTp3-Ph and MeCTp3-tBu gave monocationic complexes [(MeCTp3-Ph)MgMe][AlMe4] and [(MeCTp3-tBu)MgMe][Al2Me7] as separated ion pairs. The reaction of Mg(AlMe4)2 with nBuCTp3-Ph led to the formation of the dimagnesium complex [{(nBuCTp3-Ph)Mg(AlMe4)}2(μ-CH3)], which features a bridging methyl moiety and terminal η1-coordinated tetramethylaluminato ligands. Isopropyl-substituted ligand MeCTp3-iPr emerged from further fine-tuning of the steric and electronic parameters and, upon reaction with Mg(AlMe4)2, gave (MeCTp3-iPr)Mg(AlMe4)2; this represents the first example of a magnesium bis(alkyl) complex with an intact RCTp3-R′ ligand. The exact ligand cone angles Θ° of all magnesium complexes were determined according to the mathematical analysis developed by Allen et al. [J. Comput. Chem. 2013, 34, 1189–1197].
Symmetric diarylsulfoxides as asymmetric sulfinylating reagents for dialkylmagnesium compounds
Ruppenthal, Simon,Brückner, Reinhard
, p. 897 - 910 (2015/01/30)
At -78 °C, primary dialkylmagnesium compounds reacted with diarylsulfoxides when 1.5 equiv of the dilithium salt of (S)-BINOL was added as a promotor. Alkyl aryl sulfoxides resulted in up to quantitative yield and with up to 97% ee. This demonstrates the feasibility of asymmetric sulfinylations by achiral sulfinylating agents (from the perspective of Alkyl2Mg) as well as the feasibility of asymmetric sulfoxide-magnesium exchanges (from the perspective of Ar2SO).
Magnesium-S-omeprazole
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Page/Page column 8, (2008/06/13)
The invention provides magnesium S-omeprazolato compounds according to formula (I): [in-line-formulae][Mg(solva)x(solvb)y][Mg(S-omeprazolato)3]2.(solvc)z??(I), [/in-line-formulae] pharmaceutical compositions and processes of making the same. In formula (I), solva, solvb, and solvc represent solvent molecules where x and y are independently selected from integers 0 to 6, the sum of which is 4 or 6, while z is a positive rational number from 0 to 6. The compounds are useful for the treatment of gastric acid related conditions and the inhibition of gastric acid secretion.
Method for producing alkyl-bridged ligand systems and transition metal compounds
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, (2008/06/13)
The invention relates to a method for producing highly substituted alkyl-bridged ligand systems on the basis of indene derivatives and transition metal compounds. Said alkyl-bridged ligand systems can be obtained in high yields using this method.
The composition of methylcopper(I) species in solution. A 1H NMR study
Westmijze, H.,George, A. V. E.,Vermeer, P.
, p. 322 - 326 (2007/10/02)
The composition of methylcopper(I) species, prepared from cuprous halides and MeM (M=Li, MgX or Mg1/2) in various ratios, has been studied by means of 1H NMR spectroscopy.Tetrahydrofuran (THF) was used as solvent.Evidence is presented that in the presence of hexamethylphosphoric triamide (HMPT), methylhalocuprates, M, can be obtained stoichiometrically pure.By means of 1H NMR analysis it could be shown that the complex MeCu3 also exists in solution.The trimethyldicuprate 2Mg has only been obtained stoichiometrically pure on starting from MeMgCl and cuprous chloride; it was formed in equilibrium with 2Mg and 2Mg when the starting Grignard reagent or the cuprous halide contained bromide.Homocuprates M were always obtained in mixtures containing, in addition to the homocuprate, M and MeM when the starting reagent MeM was a Grignard reagent.Attempts to prepare species with another stoichiometry failed when Grignard reagents MeM were used.
