Nitrogen donor complexes of molybdenum and tungsten and new routes to bis-1,2 & tris-1,2,3 substituted ferrocenes
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Abstract
This Thesis describes the synthesis of nitrogen-donor complexes of molybdenum and tungsten complexes, and the preparation of 1,2-and 1,2,3-substituted ferrocenyl ligands. Refluxing [Mo(CO )6) with di pip ( di pip = 1, 1 '-methane-di-yl-bis-piperidine )in heptane gives [Mo(C0)4(dipip)](3), Using [M(C0)6] (M =Cr (2), W (4)) and dipip under uv irradiation yields [M(C0)4(dipip)). Iodine oxidation of [M(C0)4(L)2] (M = Mo, W; L= piperidine) gives [CsH10NH2][Moh(C0)3('r{O.C.NCsH10)] (10), and [WI(C0)3(NHC5H1o)(r(O.C.NC5H10)] (11). Both iodine oxidation of the bidentate complex [Mo(C0)4(dipip)] (4), and substitution of acetonitrile from [Moh(C0)3(NCCH3)2] by piperidine, afford [{MoI(μ-I)(C0)2(dipip)}2] (7, 8), reaction of [WI2(C0)3(NCCH3)2] with dipip gives [Wh(C0)3(dipip)] (9), which furnishes [WI2(C0)2(dipip)2)I (18) on further treatment with dipip. Treatment of [WI2(CO)J( dipip )], or [WI2(C0)3(NHCsH10)2], with PhC2Ph, yields [WI2(CO)(L2 or LAL)(1,2-PhC2Ph)] (L = piperidine, LAL= dipip). Lithiation of dimethylaminomethyl-ferrocene, and quench with eschenmoser's salt gave bis-1,2-dimethylaminomethyl-ferrocene ( 40), quenching with para-formaldehyde gave 1-h ydroxymeth yl-2-dimethylaminomethyl-ferrocene ( 42). 1,2-bis-di-tert-butylphosphinomethyl ferrocene ( 41) was prepared by reflux of ( 40), or ( 42) with an excess of di-tert-butyl phosphine. Quenching metallated ferrocene with para-formaldehyde was found to be water sensitive. Using calcined p. formaldehyde, gave 1-hydroxy-2,3-dimethylaminomethyl-ferrocene (46) in 91 % yield, and conversion to tris-1,2,3-di-tert-butylphosphinomethyl-ferrocene ( 47) was accomplished by reflux in acetic acid with excess di-tert-butyl phosphine. Treatment of ( 40) with excess Mel gave l-dimethylaminomethyl)-ferrocene-2-(methyltrimethylarnmonium-iodide ( 48) with Et20 as solvent, and ferrocene-bis-1,2-trimethyl-ammonium-bis-iodide ( 49) with methanol solvent. Reaction of ( 49) with P(CH20H)3, gave 1,2-bis-(di-hydroxymethyl phosphanylmethyl)-ferrocene (50), which on treatment with sodium metabisulphite gave 1,2-bis-phosphanylmethyl-ferrocene (51 ). Treatment of ( 48) with PPh3 forms 1-dimethylaminomethyl ferrocene-triphenyl phosphino iodide (52), which after treatment with phenyl lithium, undergoes Wittig coupling with 9-anthraldehyde to give 1-( dimethylaminomethyl)-2-(anthracene-9-vinyl)-ferrocene (53). (41) and (47) were tested as catalyst ligands in the copolymerisation of ethene, carbon monoxide and methanol. ( 47) was found to rival the performance of bis-1,2-di-tert-butylphosphinomethyl-benzene, whilst (41) was found to exceed the turnover performance with an average (mean) turnover number of 61,941 moles catalyst/ moles product after 3 hours.
Details
Original language | English |
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Award date | 2004 |