P. Espinet

Cationic palladium(II) complexes involving unprecedented O-coordination of acetylmethylenetriphenylphosphorane

Abstract Cationic pentafluorophenyl palladium(II) complexes of the type [Pd(C6F5)L2(APPY)]ClO4 (L = PPh3, PBu3n; L2 = bipy and A acetylmethylenetriphenylphosphorane) have been prepared by addition of APPY to the perchlorato complexes [Pd(OClO3)(C6F5)L2]; the APPY ligand is O-coordinated, which is unprecedented in keto-stabilized ylide complexes of palladium. The neutral complex Pd(C6F5)(Cl)(tht)(APPY) has been made by addition of APPY to the binuclear complex Pd2(μ-Cl)2(C6F5)2(tht)2 (tht = tetrahydrothiophene); in which the APPY ligand shows the normal C-coordination.

Bis (pentafluorophenyl) complexes of palladium(II) and of platinum(II)

Abstract The preparation of eight bis(pentaflurophenyl) complexes of Pd 11 and of Pt 11 with monodentate and bidentate nitrogen-donor ligands is described together with a preparation of a Pd 11 complex of 1,2-bis(diphenylphosphino)ethane. Some properties of the complexes are given. New possibilities for assignment of cis or trans configuration are discussed which depend upon the splitting or disappearance of certain bands in the IRspectra.

Reactions of [Pd(C6F5)2(CNR)2] with [PdCl2(NCPh)2]. Insertion of p-MeC6H4NC into Pd-C6F5 bonds

[Pd(C6F5)2(CNR)2] (R = Cy, But, p-MeC6H4 (p-Tol)) react with [PdCl2(NCPh)2] to give [Pd2(μ-Cl)2(C6F5)2(CNR)2]. In refluxing benzene insertion of isocyanide into the C6F5Pd bonds occurs only for R = p-Tol, to give a imidoyl bridged polynuclear complex cis-[Pd2 (μ-Cl)2[μ-C(C6F5) = N(Tol-p)]2n]. This complex reacts with (a) Tl(acac) to give [Pd2{μ-C(C6F5) = N(Tol-p)}2(acac)2]; (b) neutral monodentate ligands to afford dimeric complexes [Pd2{μ-C(C6F5) = N(Tol-p)}2Cl2L2] (L = NMe3, py, 4-Me-py, SC4H8), and (c) isocyanides to give insoluble complexes of the same composition which are thought to be polymeric, [Pd(CNR)Cl{μ-C(C6F5) = N(p-Tol)}]n (R = p-Tol, Me, But). Thermal decomposition of cis-[Pd2 (μ-Cl)2 [μ-C(C6F5) = N( p-Tol)]2n] gives the diazabutadiene species (p-Tol)NC(C6F5)C(C6F5)N(p-Tol) in high yield.

Pentafluorophenyl Platinum(II) and Platinum(IV) Complexes with o-Phenylenebisdimethylarsine

Abstract The preparation of platinum(II) complexes of the types PtRX(diars) and PtR2(diars) (R = C6F5; X= Cl, Br or I; diars= o-phenylenebisdimethylarsine) and their reactions with halogens to give PtRX3 (diars) or, respectively, PtR2X2 (diars) is described.

C(C6F4PPh2-o)NMe a C,P-chelate and C,N-bridging ligand. Crystal structure of

Abstract Addition of PPh 2 H and base to cis -[{Pd 2 (μ-Cl) 2 [μ-C((C 6 F 5 )=N(Me)] 2 } n ] results in formation of a CP bond at the expense of a CF bond to give the title complex, the crystal structure of which has been determined.

Synthesis of neutral and cationic pentafluorophenylpalladium(I) derivatives. Insertion versus coordination of isocyanides in binuclear palladium(I) complexes

Abstract Reaction between PdX(C6F5)(dpm)2 (dpm = bis(diphenylphosphino)methane; X = Cl, Br, I, CNO or C6F5) and Pd2(dba)3CHCl3 (dba = dibenzylideneacetone) gives, the pentafluorophenyl palladium(I) derivatives [XPd(μ-dpm)2Pd(C6F5)]. Treatment of [ClPd(μ-dpm)2Pd(C6F5)] with an excess of the ligand L, and in the presence of NaBPh4 gives the cationic complexes [LPd(μ-dpm)2Pd(C6F5)]BPh4 (L = PPh3, P(OPh)3, pyridine or tetrahydrothiophene (tht)). Reaction with isocyanides RNC leads to three different types of compounds: (a) products with the isocyanide groups inserted into the PdPd bond [(μ-RNC){;XPd(μ-dpm)2Pd(C6F5)};] (X = C6F5; R = p-tolyl; X = Cl, R = p-tolyl or Cy); (b) cationic complexes with terminal isocyanides [(RNC)Pd(μ-dpm)2Pd(C6F5)]X (X = Cl; R = t-Bu; X = BPh4, R = p-tolyl, Cy or t-Bu) and (c) complexes which contain both bridging and terminal isocyanides, [(μ-RNC){;(RNC)Pd(μ-dpm)2Pd(C6F5};BPh4] (R = p-tolyl or cyclohexyl). Addition of NaBPh4 to solutions of complexes of type a (X = Cl) results in deinsertion of the isocyanide to give complexes of type b. IR spectroscopy reveals that [(μ-CyNC){;ClPd(μ-dpm)2Pd(C6F5)};] isomerizes in CH2Cl2 to give [(CyNC)Pd(μ-dpm)2pd(C6F5)]Cl, which upon recrystallization regenerates the former complex, showing that in this case the insertion-deinsertion process is reversible.

Cyano-organopalladate complexes and their cyanobridged derivatives

Abstract The preparations of anionic complexes of the types Q 2 [(C 6 F 5 ) x Pd(CN) 4− x ] ( x = 1, 2( cis and trans ), 3; Q = ammonium or phosphonium cation) and (N-n-Bu 4 )[(η 3 -C 3 H 5 )Pd(CN) 2 ] are described. Their reactions with palladium perchlorato complexes give polynuclear neutral, anionic or cationic cyanobridged derivatives. The proposed structures of the new complexes are based on their IR spectra.

Terminal pentafluorobenzimidoylpalladium(II) complexes. X-ray structure of trans-[Pd{C(C6F5)NMe}Cl(CNMe)2]

Abstract The preparations of the complexes trans -[Pd{C(C 6 F 5 )N(R 1 )}Cl(CNR 2 ) 2 ] and [Pd{C(C 6 F 5 )N(R 1 )}(CNR 2 ) 2 ]X (R 1 = Me, p -Tol; R 2 = Me, p -Tol, Bu t ; X = ClO 4 or BPh 4 ) from [Pd 2 {μ-C(C 6 F 5 )N(R 1 )} 2 Cl 2 (CNR 2 ) 2 ] are described. The splitting of the imidoyl bridges is accompanied by an isomerization of the imidoyl group from the syn to the anti conformation as shown by a single crystal X-ray diffraction study of trans -[Pd{C(C 6 F 5 )N(Me)}Cl(CNMe) 2 ]. Attempted preparations of [Pd{C(C 6 F 5 )=N(R 1 )}Cl(PPh 3 ) 2 ] from [Pd 2 -C(C 6 F 5 )N(R 1 )} 2 Cl 2 (PPh 3 ) 2 ] led to elimination of CNR and formation of trans -[Pd(C 6 F 5 )Cl(PPh 3 ) 2 ]; this is the first example of isonitrile elimination in palladium chemistry.

Single-bridged halide or pseudohalide complexes of palladium(II)

Abstract The synthesis of cationic binuclear palladium complexes of the type {(μ-X)[Pd(C6F5)L2][Pd(C6F5)L′]}ClO4 (L = N or P donors) is described. X can be a pseudohalide, such as CN, SCN or N3, or a halide when L2 is a bidentate N-ligand, such as bipy. Trinuclear complexes of the type {[(PPh3)2Pd](μ-X)2[Pd(C6F5)L2]2}ClO4 have only been obtained for X = CN. For X = other pseudohalide or halide, rearrangement reactions render binuclear double-bridged species along with binuclear single-bridged species of the above-mentioned type. The preparation of a pentanuclear complex {[Pd(μ-CN)4][Pd(C6F5)(PPh3)2]4}(ClO4)2 is also described.

Bis(pentafluorophenyl)-platinum(II) and -platinum(IV) complexes

Abstract The preparation of five new platinum(II) complexes of the general formula (C 6 F 5 ) 2 PtL 2 (L 2 = Ph 2 AsCH 2 CH 2 AsPh 2 ; and the cis - and trans -isomers when L = PBu 3 or AsPh 3 ) is described. The oxidative addition of X 2 (X = Cl or Br) to some compounds of the aforementioned type leads to eight new platinum(IV) complexes X 2 (C 6 F 5 ) 2 PtL 2 (L = PBu 3 ; L 2 = 2,2′ -bipyridine, 1,10-phenanthroline or Ph 2 AsCH 2 CH 2 AsPh 2 ).