Poli, Rinaldo published the artcileAn experimental and computational study on the effect of Al(OiPr)3 on atom-transfer radical polymerization and on the catalyst-dormant-chain halogen exchange, Quality Control of 31253-08-4, the publication is Chemistry – A European Journal (2005), 11(8), 2537-2548, database is CAplus and MEDLINE.
Compound Al(OiPr)3 is shown to catalyze the halide-exchange process leading from [Mo(Cp)Cl2(iPrN=CH-CH=NiPr)] and CH3CH-(X)COOEt (X=Br, I) to the mixed-halide complexes [Mo(Cp)ClX(iPrN=CH-CH=NiPr)]. No significant acceleration is observed for the related exchange between [MoX3(PMe3)3] (X=Cl, I) and PhCH(Br)CH3, by analogy to a previous report dealing with the RuII complex [RuCl2(PPh3)3]. A DFT computation study, carried out on the model complexes [Mo(Cp)Cl2(PH3)2], [MoCl3(PH3)3], and [RuCl2(PH3)3], and on the model initiators CH3CH(Cl)COOCH3, CH3Cl, and CH3Br, reveals that the 16-electron RuII complex is able to coordinate the organic halide RX in a slightly exothermic process to yield saturated, diamagnetic [RuCl2(PH3)3(RX)] adducts. The 15-electron [MoCl3(PH3)3] complex is equally capable of forming an adduct, i.e., the 17-electron [MoCl3(PH3)3(CH3Cl)] complex with a spin doublet configuration, although the process is endothermic, because it requires an energetically costly electron-pairing process. The interaction between the 17-electron [Mo(Cp)Cl2(PH3)2] complex and CH3Cl, is repulsive and does not lead to a stable 19-electron adduct. The [RuCl2(PH3)3(CH3X)] system leads to an isomeric complex [RuClX(PH3)3(CH3Cl)] by internal nucleophilic substitution at the carbon atom. The transition state of this process for X=Cl (degenerate exchange) is located at lower energy than the transition state required for halogen-atom transfer leading to [RuCl3(PH3)3] and the free radical CH3. On the basis of these results, the uncatalyzed halide exchange is interpreted as the result of a competitive SNi process, whose feasibility depends on the electronic configuration of the transition-metal complex. The catalytic action of Al(OiPr)3 on atom-transfer radical polymerization (and on halide exchange for the 17-electron half-sandwich MoIII complex) results from a more favorable Lewis acid-base interaction with the oxidized metal complex, in which the transferred halogen atom is bound to a more electro-pos. element. This conclusion derives from DFT studies of the model [Al(OCH3)3]n (n=1,2,3,4) compounds, and on the interaction of Al(OCH3)3 with CH3Cl and with the [Mo(Cp)Cl3(PH3)2] and [RuCl3(PH3)3] complexes.
Chemistry – A European Journal published new progress about 31253-08-4. 31253-08-4 belongs to iodides-buliding-blocks, auxiliary class Iodide,Ester, name is Ethyl 2-Iodopropionate, and the molecular formula is C5H9IO2, Quality Control of 31253-08-4.
Referemce:
https://en.wikipedia.org/wiki/Iodide,
Iodide – an overview | ScienceDirect Topics – ScienceDirect.com