Highly Trifluoromethylated Platinum Compounds

Abstract

The homoleptic, square‐planar organoplatinum(II) compound [NBu4]2[Pt(CF3)4] (1) undergoes oxidative addition of CF3I under mild conditions to give rise to the octahedral organoplatinum(IV) complex [NBu4]2[Pt(CF3)5I] (2). This highly trifluoromethylated species reacts with Ag+ salts of weakly coordinating anions in Me2CO under a wet‐air stream to afford the aquo derivative [NBu4][Pt(CF3)5(OH2)] (4) in around 75 % yield. When the reaction of 2 with the same Ag+ salts is carried out in MeCN, the solvento compound [NBu4][Pt(CF3)5(NCMe)] (5) is obtained in around 80 % yield. The aquo ligand in 4 as well as the MeCN ligand in 5 are labile and can be cleanly replaced by neutral and anionic ligands to furnish a series of pentakis(trifluoromethyl)platinate(IV) compounds with formulae [NBu4][Pt(CF3)5(L)] (L=CO (6), pyridine (py; 7), tetrahydrothiophene (tht; 8)) and [NBu4]2[Pt(CF3)5X] (X=Cl (9), Br (10)). The unusual carbonyl–platinum(IV) derivative [NBu4][Pt(CF3)5(CO)] (6) is thermally stable and has a νCO of 2194 cm−1. The crystal structures of 2⋅CH2Cl2, 5, [PPh4][Pt(CF3)5(CO)] (6′), and 7 have been established by X‐ray diffraction methods. Compound 2 has shown itself to be a convenient entry to the chemistry of highly trifluoromethylated platinum compounds. To the best of our knowledge, compounds 2 and 4–10 are the organoelement compounds with the highest CF3 content to have been isolated and adequately characterized to date.

Gold(I) and Gold(III) Trifluoromethyl Derivatives

“…At molecular level, the CF 3 -Au-CO unit shows a strictly linear structure (Figure 4), as the C-Au-C vector coincides longitudinally with a crystallographic C 3 axis. The Au À CF 3 bond length (204.7 (14) [46] and from that observed in the parent species 1' (203.3(2) pm) in spite of the different global charge on each complex and the different trans influence of CF 3 versus CO. [47] The Au À CO bond length (197.7(16) pm) is in the upper range of Au À CO distances in gold carbonyl compounds for which the molecular structure has been established (Table 1), being indistinguishable from those found in the cationic monocarbonyl derivative [Au(CO)A C H T U N G T R E N N U N G (SIDipp)] + (197.1(5) pm), [45c] and in the dicarbonyl species [Au(CO) 2 ] + (197.1(8) pm). [48] The C À O bond length in compound 6 (108(2) pm) is, in turn, in the lower range found in any structurally characterized metal carbonyl species.…”

The Trifluoromethyl Group in Transition Metal Chemistry

“…This reaction involves the stereoselective loss of one of the CF 3 groups trans to another CF 3 in the precursor derivative upon acidic treatment. [147] Given the stoichiometry of the reaction product, it could not be directly established whether the addition occurred in a cis or in a trans manner. The compound was isolated as its [NBu 4 ] + salt in high yield and its geometry was determined in solution ( 19 F NMR spectroscopy) as well as in the solid state (X-ray crystallography).…”

“…The compound was isolated as its [NBu 4 ] + salt in high yield and its geometry was determined in solution ( 19 F NMR spectroscopy) as well as in the solid state (X-ray crystallography). [147] The molecular structure of the nitrile derivative was established by single-crystal Xray diffraction methods ( Figure 14). Scheme 5 I], which was isolated as a white solid in 75 % yield and characterized in solution (NMR spectroscopy) and in the solid state (Xray crystallography).…”

“…[145] Notably, the stereochemical variety found in the trifluoromethyl-platinate(IV) derivatives with the successful stereospecific synthesis and isolation of the cis/trans and fac/mer couples has no parallelism in the by far better developed methyl-platinum chemistry. [147] Some of these as well as other [Pt(CF 3 ) 5 X] 2compounds (X = F, Cl, CN), including the highly interesting homoleptic [Pt(CF 3 ) 6 ] 2species, have been detected and competently identified in solution ( 19 F and 195 Pt NMR spectroscopy) but could not be isolated in pure form. [147] Given the stoichiometry of the reaction product, it could not be directly established whether the addition occurred in a cis or in a trans manner.…”

Solid‐State and Solution Structure of a Hypervalent AX5 Compound: Sb(C6F5)5

“…General working techniques are described in ref. 24. Additionally, a Bruker AV 500 spectrometer was used to obtain the variable‐temperature 19 F NMR spectroscopic data.…”