Synthesis of Magnesium Compounds XMgY(X=R,Br; Y= NR2, NPh2) and Studies of CO2 insertion into Mg-C and Mg-N
2001
Hochschulschrift
Zugriff:
89
The 1:1 reaction between MgR2 and diphenylamine gave heteroleptic alkyl -magnesium amide monomeric compounds [RMgNPh2(THF)2] [R=Et (1) and iPr (2)]. Subsequently, addition of stronger donor solvent HMPA to compound 1 results in the disproportionation reaction to give a bisamidomagnesium crystal [Mg(NPh2)2(HMPA)2] (3). The different size secondary amine HNEt2 or HN(SiMe3)2 reacting with Grignard reagent EtMgBr produced diethylamino-bridging and bromo-bridging Hauser base [(Me3Si)2NMg(μ-Br)(OEt2)]2 (4) and [BrMg(μ-NEt2)(HMPA)]2(5) respectively. Unexpectedly, [(Me3Si)NMg (μ-OEt)(THF)]2 (6) was obtained from the reaction of MgEt2 and HN(SiMe3)2 in the refluxing THF solution. Additionally, iPrMgBr and MgY2 (Y = iPr, C�kCSiMe3, NMe2, NEt2, NPh2) react with carbon dioxide, yielding different bridging carboxylato and carbamato magnesium compounds: [Mgn(O2CY)2n(Sol)m] [n = 3, m = 2, Y = iPr, Sol = THF (7), HMPA (HMPA=hexamethylphosphoramide) (8); n = 3, m = 4, Y = C�kCSiMe3, Sol = HMPA (9); n = 3, m = 2, Y = NMe2, Sol = THF (10), HMPA (11); n = 6, m = 0, Y = NEt2 (12)及NPh2 (13)] The addition of HMPA/THF to hexamer 13 resulted in a deaggregation reaction, yielding the dimer [Mg2(O2CNPh2)4(HMPA)2] (14). Bubbling carbon dioxide into the THF solution of Mg(NiPr2)2, we unexpectedly obtained two novel compounds: [Mg6(μ4-O)(O2CNiPr2)10] (15) and [ Mg5(μ5,η6–CO3)(O2CNiPr2)8(HMPA)2 ] (16), which were isolated from THF/hexane and HMPA/toluene solvents, respectively. X-ray crystallographic determinations were performed on compounds 8, 9 and 11~16, which were found to be either linear or cage compounds, depending upon the steric size of Y, the bonding mode between magnesium atoms and the bridging carboxylato, carbamato or carbonato. These compounds were characterized using 1H, 13C NMR, IR spectroscopy, mass spectrometer, and elemental analyses.
Titel: |
Synthesis of Magnesium Compounds XMgY(X=R,Br; Y= NR2, NPh2) and Studies of CO2 insertion into Mg-C and Mg-N
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Autor/in / Beteiligte Person: | Yang, Kuo-Ching ; 楊國清 |
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Veröffentlichung: | 2001 |
Medientyp: | Hochschulschrift |
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