title: Homeomorphic Isomerization as a Design Element in Container Molecules; Binding, Displacement, and Selective Transport of MCl2Species (M = Pt, Pd, Ni).
abstract: The dibridgehead diphosphine ((CH2)14)3P (1) can rapidly turn inside-out (homeomorphic isomerization) to give a mixture of in,in and out,out isomers. The exo directed lone pairs in the latter are able to scavenge Lewis acidic MCl2; cagelike adducts of the in,in isomer, trans- Cl2(P((CH2)14)3P) (M = 2/Pt, 3/Pd, 4/Ni), then form. The NiCl2unit in 4 may be replaced by PtCl2or PdCl2, but 2 and 3 do not give similar substitutions. U-tubes are charged with CH2Cl2solutions of 1 (lower phase), an aqueous solution of K2MCl4(charging arm; M = Pt, Pd), and an aqueous solution of excess KCl (receiving arm). The MCl2units are then transported to the receiving arm until equilibrium is reached (up to 22 d). When the receiving arm is charged with KCN, transport is much faster (ca. 100 h) and higher K2MX4equilibrium ratios are obtained (≥96≤4). Analogous experiments with K2PtCl4/K2PdCl4mixtures show PdCl2transport to be more rapid. A similar diphosphine with longer methylene chains, P((CH2)18)3P, is equally effective. No transport occurs in the absence of 1, and other diphosphines or monophosphines assayed give only trace levels.
authors.affiliation: Department of Chemistry, Texas A&M University , P.O. Box 30012, College Station, Texas 77842-3012, United States.
authors.forename: Sugam
authors.identifier: 0000-0001-6106-4639
authors.initials: S
authors.lastname: Kharel
authors.affiliation: Department of Chemistry, Texas A&M University , P.O. Box 30012, College Station, Texas 77842-3012, United States.
authors.forename: Hemant
authors.identifier: 0000-0002-7616-0241
authors.initials: H
authors.lastname: Joshi
authors.affiliation: Department of Chemistry, Texas A&M University , P.O. Box 30012, College Station, Texas 77842-3012, United States.
authors.forename: Stephen
authors.initials: S
authors.lastname: Bierschenk
authors.affiliation: Department of Chemistry, Texas A&M University , P.O. Box 30012, College Station, Texas 77842-3012, United States.
authors.forename: Michael
authors.initials: M
authors.lastname: Stollenz
authors.affiliation: Department of Chemistry, Texas A&M University , P.O. Box 30012, College Station, Texas 77842-3012, United States.
authors.forename: Deeb
authors.initials: D
authors.lastname: Taher
authors.affiliation: Department of Chemistry, Texas A&M University , P.O. Box 30012, College Station, Texas 77842-3012, United States.
authors.forename: Nattamai
authors.initials: N
authors.lastname: Bhuvanesh
authors.affiliation: Department of Chemistry, Texas A&M University , P.O. Box 30012, College Station, Texas 77842-3012, United States.
authors.forename: John A
authors.identifier: 0000-0002-7012-4872
authors.initials: JA
authors.lastname: Gladysz