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Stepwise Degradation of Trifluoromethyl Platinum(II) Compounds

Authors

  • Dr. Sonia Martínez-Salvador,

    1. Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Universidad de Zaragoza–CSIC, C/Pedro Cerbuna 12, E-50009 Zaragoza (Spain), Fax: (+34) 976-761-187
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  • Prof. Dr. Juan Forniés,

    Corresponding author
    1. Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Universidad de Zaragoza–CSIC, C/Pedro Cerbuna 12, E-50009 Zaragoza (Spain), Fax: (+34) 976-761-187
    • Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Universidad de Zaragoza–CSIC, C/Pedro Cerbuna 12, E-50009 Zaragoza (Spain), Fax: (+34) 976-761-187
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  • Dr. Antonio Martín,

    1. Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Universidad de Zaragoza–CSIC, C/Pedro Cerbuna 12, E-50009 Zaragoza (Spain), Fax: (+34) 976-761-187
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  • Dr. Babil Menjón,

    1. Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Universidad de Zaragoza–CSIC, C/Pedro Cerbuna 12, E-50009 Zaragoza (Spain), Fax: (+34) 976-761-187
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  • Dr. Isabel Usón

    1. Institució Catalana de Recerca i Estudis Avançats (ICREA), Institut de Biologia Molecular de Barcelona–CSIC, C/Baldiri Reixach 13–15, E-08028 Barcelona (Spain)
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Abstract

The action of moisture on the homoleptic organoplatinum(II) compound [NBu4]2[Pt(CF3)4] (1) gives rise to the carbonyl derivative [NBu4][Pt(CF3)3(CO)] (2), which is itself moisture stable. However, treatment of compound 2 with HCl(aq) results in the formation of [NBu4][cis-Pt(CF3)2Cl(CO)] (3), which undergoes degradation of an additional CF3 group by further treatment with HCl(aq) in large excess, affording [NBu4][cis-Pt(CF3)Cl2(CO)] (4). The carbonyl derivatives 24 are fairly stable species, in which the CO ligand, however, can be readily extruded by reaction with trimethylamine N-oxide (ONMe3). Thus, compound 2 reacts with ONMe3 in the presence of a number of neutral or anionic ligands affording a series of singly or doubly charged derivatives with the general formulae [NBu4][Pt(CF3)3(L)] [L=CNtBu (5), PPh3 (6), P(o-tolyl)3 (7), tht (8; tht=tetrahydrothiophene)] and [NBu4]2[Pt(CF3)3X] [X=Cl (9), Br (10), I (11)], respectively. Compound 2 also reacts with ONMe3 and pyridin-2-thiol (C5H5NS) giving rise to the five-membered metallacyclic derivative [NBu4][Pt(CF3)2(CF2NC5H4S-κCS)] (12), which can be viewed as a difluorocarbene species stabilized by intramolecular base coordination. On the other hand, treatment of compound 3 with ONMe3 in the presence of C5H5NS yields the four-membered metallacyclic compound [NBu4][Pt(CF3)2(NC5H4S-κNS)] (13). The geometries of the metallacycles in compounds 12 and 13 are compared. In the absence of any additional ligand, compound 3 undergoes dimerization producing the dinuclear species [NBu4]2[{Pt(CF3)2}2(μ-Cl)2] (14). Halide abstraction in the latter compound with AgClO4 in THF yields the solvento compound cis-[Pt(CF3)2(thf)2] (15). The highly labile character of the THF ligands in compound 15 makes this species a convenient synthon of the “cis-Pt(CF3)2” unit.

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