[PtCl₃(C₂H₄)]^-[(S,S)-(PhMeCH)₂NH₂]⁺:  A New and Versatile Ionic Organometallic Chiral Derivatizing Agent for the Determination of the Enantiomeric Composition of Chiral Unsaturated Compounds by ¹⁹⁵Pt NMR Spectroscopy

Abstract

The ionic complex [PtCl(3)(C(2)H(4))](-)[(S,S)-(PhMeCH)(2)NH(2)](+) containing a chiral secondary amine is a new and versatile chiral derivatizing agent (CDA) for the determination of the enantiomeric composition of several unsaturated compounds including simple olefins: the diastereoisomeric mixtures arising from the exchange of ethylene by the unsaturated analytes are easily detected by (195)Pt NMR spectroscopy.

trans-[PtCl2(Am)(C2H4)] and [PtCl3(C2H4)]−[AmH]+, Containing Binaphthyl Secondary Amines − Efficient Chiral Derivatizing Agents for the Enantiodiscrimination of Chiral Olefins by 195Pt NMR Spectroscopy

“…[19,20] The complexes ionic-b and trans-b were prepared starting from Zeise's salt, [17,18] using the amine b in its hydrochloride salt and free base forms, respectively. Both were characterized by NMR spectroscopy.…”

“…Literature methods were used to prepare 3-phenyl-1-butene (1), [21] 3,4-dimethyl-1-pentene (2), [21] 5,5-dimethyl-4-phenyl-1-hexene (4), [21] 5-methyl-4-phenyl-1-hexene (5), [21] 4-methyl-1-hexene (6), [21] 1-phenyl-3,4,4-trimethyl-1,2-pentadiene (8), [22] 3-methyl-1-phenyl-1,2-pentadiene (9), [22] 1-phenylethyl vinyl ether (10), [23] 2,2-dimethyl-1-phenylpropyl vinyl ether (11), [23] (12), [23] 2-vinyltetrahydropyran (13), [24] and 3-methoxy-3-phenyl-1-butene (7). [25] (1S,1ЈS)-Bis [1-(1-naphthyl)ethyl]amine (a) [17,18] and its complex ionic-a were prepared as described elsewhere. [17,18] (S)-3,5-Dihydro-4H-dinaphth[2,1-c:1Ј,2Ј-e]azepine (b) was prepared by following the literature procedure (Supporting Information).…”

“…[25] (1S,1ЈS)-Bis [1-(1-naphthyl)ethyl]amine (a) [17,18] and its complex ionic-a were prepared as described elsewhere. [17,18] (S)-3,5-Dihydro-4H-dinaphth[2,1-c:1Ј,2Ј-e]azepine (b) was prepared by following the literature procedure (Supporting Information). [19,20] trans-Dichloro(b)(ethylene)platinum(II) (trans-b) …”

“…A significant contribution in this field has arisen from the development of organometallic CDAs, [10Ϫ16] the use of which can involve the coordination of π-moieties to the metal center as a derivatization process, thus making the analysis of unsaturated or aromatic compounds possible. We have recently introduced [17,18] the new and promising organometallic CDAs trans-[PtCl 2 (Am)(C 2 H 4 )] (trans) and [PtCl 3 (C 2 H 4 )] Ϫ [AmH] ϩ (ionic) (Scheme 1), containing chiral secondary amines, for the enantiomeric composition determination of several classes of unsaturated compounds. These were prepared by very simple experimental procedures from Zeise's salt, [17,18] and their use as CDAs is based on the exchange of coordinated ethylene by the enantiomers of the chiral unsaturated compounds (Scheme 2).…”

“…We have recently introduced [17,18] the new and promising organometallic CDAs trans-[PtCl 2 (Am)(C 2 H 4 )] (trans) and [PtCl 3 (C 2 H 4 )] Ϫ [AmH] ϩ (ionic) (Scheme 1), containing chiral secondary amines, for the enantiomeric composition determination of several classes of unsaturated compounds. These were prepared by very simple experimental procedures from Zeise's salt, [17,18] and their use as CDAs is based on the exchange of coordinated ethylene by the enantiomers of the chiral unsaturated compounds (Scheme 2). The corresponding diastereoisomeric mixtures were analyzed by 195 Pt NMR spectroscopy.…”