Coordination Properties of Perfluoroethyl‐ and Perfluorophenyl‐Substituted Phosphonous acids,RfP(OH)2 |
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| Authors: | Dr Nadine Allefeld Dr Boris Kurscheid Beate Neumann Dr Hans‐Georg Stammler Dr Nikolai Ignat'ev Prof?Dr Berthold Hoge |
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| Institution: | 1. Centrum für Molekulare Materialien, Fakult?t für Chemie, Anorganische Chemie II, Universit?t Bielefeld, Universit?tsstrasse 25, 33619 Bielefeld (Germany);2. PM‐APR‐FT, Merck KGaA, Frankfurter Strasse 250, 64293 Darmstadt (Germany) |
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| Abstract: | Phosphinic acids, RfP(O)(OH)H (Rf=CF3, C2F5, C6F5), turned out to be excellent preligands for the coordination of phosphonous acids, RfP(OH)2. Addition of C2F5P(O)(OH)H to solid PtCl2 under different reaction conditions allows the isolation and full characterization of the mononuclear complexes ClPt{P(C2F5)(OH)O}{P(C2F5)(OH)2}2] and Pt{P(C2F5)(OH)O}2{P(C2F5)(OH)2}] containing hydrogen‐bridged RfP(OH)O]? and RfP(OH)2 units. Further deprotonation of Pt{P(C2F5)(OH)O}2{P(C2F5)(OH)2}2] leads to the formation of the dianionic platinate, Pt{P(C2F5)(OH)O}4]2?, revealing four intramolecular hydrogen bridges. With PdCl2 the dinuclear complex Pd2(μ‐Cl)2{P(C2F5)(OH)O]2H}2] was isolated and characterized. The Cl? free complex Pd{P(C2F5)(OH)O}2{P(C2F5)(OH)2}2] was also prepared and deprotonated to the dianionic palladate, Pd{P(C2F5)(OH)O}4]2?. Both compounds were characterized by NMR spectroscopy, IR spectroscopy, and X‐ray analyses. In addition, the C6F5 derivatives ClPt{P(C6F5)(OH)O}{P(C6F5)(OH)2}2] and Pd2(μ‐Cl)2{P(C6F5)(OH)O]2H}2] as well as the CF3 derivative Pd2(μ‐Cl)2{P(CF3)(OH)O]2H}2] were synthesized and fully characterized. Phosphonous acid complexes are inert towards air and moisture and can be stored for several months without decomposition. The catalytic activity of the palladium complexes in the Suzuki cross‐coupling reaction between 1‐bromo‐3‐fluorobenzene and phenyl boronic acid was demonstrated. |
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| Keywords: | coordination modes cross‐coupling fluorine palladium phosphorus platinum |
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