Francisco Ruiz

New mono- and bis(pentafluorophenyl)palladium(II) complexes with iminophosphine ligands. Crystal structure of [Pd(C6F5)(SC6H5)(o-Ph2PC6H4–CHNiPr)]

Abstract The synthesis of new mono- and bis(pentafluorophenyl) derivatives of palladium(II) with the mixed-donor bidentate ligands o-Ph2PC6H4–CHNR (RN–P) has been achieved. The new complexes of general formula [Pd(C6F5)2(RN–P)] [R=Me (1), Et (2), nPr (3) iPr (4), tBu (5), Ph (6), NH–Me (7)] and [Pd (C6F5)Cl(RN–P)] [R=Me (8), iPr (9), NH–Me (10)] have been, respectively, prepared by reaction between the labile precursors cis-[Pd(C6F5)2(PhCN)2] or [{Pd(C6F5)(tht)(μ-Cl)}2] (tht=tetrahydrothiophene) and the corresponding iminophosphines. Complex (9) undergoes metathetical exchange of chloride with anionic monodentate ligands when reacting with alkaline salts, giving the complexes of formula [Pd(C6F5)X(iPrN–P)] [X=Br (11), I (12), CN (13), SCN (14), SC6H5 (15), p-SC6H4Me (16), p-SC6H4NO2 (17), OMe (18)]. Furthermore, when the chloropentafluorophenyl complex (9) was treated with silver trifluoromethanesulfonate in the presence of tertiary phosphines, the cationic derivatives [Pd(C6F5)(L)(iPrN–P)](CF3SO3) [L=PEt3 (19), PMe2Ph (20), PMePh2 (21)] were obtained in good yield. The new complexes were characterized by partial elemental analyses and spectroscopic methods (IR, 1H, 19F and 31P NMR). The molecular structure of complex (15) has been determined by a single-crystal diffraction study, showing that the iminophosphine act as chelating ligand with coordination around the palladium atom slight distorted from the square-planar geometry.

Bis(pentafluorophenyl)nickel(II) complexes with α-diimines and iminophosphines

Abstract New bis(pentafluorophenyl) derivatives of nickel(II) have been prepared by reaction between cis -[Ni(C 6 F 5 ) 2 (PhCN) 2 ] and bidentate chelate ligands L 2 . The new complexes of general formula [Ni(C 6 F 5 ) 2 L 2 ] containing mixed-donor bidentate ligands (L 2 = iminophosphine: P( o -C 6 H 4 CH=N-R); R = Me, Et, n Pr, i Pr, l Bu, Ph, NH-Me) or symmetrical ligands (L 2 = α-diimine: R 1 N=CR-CR=NR 1 R = H, R 1 = Ph, C 6 H 4 Me- o or C 6 H 4 Me- p ; R = Me, R 1 = Ph, C 6 H 4 Me- o or C 6 H 4 Me- p ) have been characterized by partial elemental analyses and spectroscopic methods (IR, and 1 H, 31 P and 19 F NMR).

Di- and tri-nuclear nickel(II) complexes with bridging thiolato groups. Crystal structure of [NBu4]2[Ni3(C6F5)4(µ-SEt)4]

The hydroxo complex [NBu4]2[Ni2(C6F5)4(µ– OH)2] reacts with H2S or a thiol at room temperature in methanol to give the binuclear complexes [NBu4]2[Ni2(C6F5)4(µ– SR)2](R = H, Me, Et, Pri, Ph or C6H4Me-p). The trinuclear complex [NBu4]2[Ni3(C6F5)4(µ– SEt)4] has been obtained by reaction of an excess of EtSH with the same hydroxo complex in refluxing methanol. The µ–azolato-µ-thiolato complexes [NBu4]2[Ni2(C6F5)4(µ– L)(µ– SR)](HL = pyrazole or 1,2,4-triazole; R = H, Ph or C6H4Me-p) can be prepared either by treating the µ-hydroxo–µ-azolato complexes [NBu4]2[Ni2(C6F5)4(µ– OH)(µ– L)] with H2S or a thiol (1:1 molar ratio) or [NBu4]2[Ni2(C6F5)4(µ– OH)2] with the corresponding thiol and azole (1:1:1 molar ratio). Analytical (C, H, N, S), conductance and spectrroscopic (IR, 1H and 19F NMR) data have been used for structural assignments. An X-ray crystal structure determination of [NBu4]2[Ni3(C6F5)4(µ– SEt)4] has established the trinuclear nature of the anion. The structure has been solved and refined to R= 0.052 and R′= 0.062 based on 3398 observed reflections. The Ni atoms are four-co-ordinated and show approximate square-planar arrangements. The bridge conformation could be determined by S ⋯ S repulsions.

Organometallic Nickel(II) Complexes Containing Thiolate and Dithiocarbamate Ligands

The mono(pentafluorophenyl)nickel(II) complexes [Ni(C6F5)ClL2] (L = PPhMe2, PPh2Me; L2 = dppe) react with KSR (R = Ph, C6H4Me-p, C6H4OMe-p, C6H4Cl-p, C6H3Cl22,6, C6H4NO2-p) at room temperature in acetone/dichloromethane to give the mononuclear thiolate complexes [Ni(C6F5)(SR)L2]. The binuclear μ-thiolate complex [{Ni(C6F5)(PPhMe2)}2(μ-SC6H4NO2-p)2] is obtained by reaction of KSC6H4NO2-p with the same chloro complex in refluxing dichloromethane. A single-crystal X-ray diffraction study of [Ni(C6F5)(SC6H4NO2-p)(PPhMe2)2] and [{Ni2(C6F5)2(PPhMe2)2(μ-SC6H4NO2-p)2] has established the mononuclear and binuclear nature of the complexes. The di-

Theophylline antagonizes the effect of diazepam on ventricular automaticity

The effect of diazepam on ventricular automaticity induced by a local injury was investigated in the isolated right ventricle of the rat in the presence of the diazepam central antagonist, RO 15-1788, and of the adenosine antagonist, theophylline. Theophylline but not RO 15-1788 antagonized the inhibitory effect induced by diazepam on ventricular automaticity. The inhibitory effect of adenosine but not that of 2-chloroadenosine was potentiated in the presence of diazepam. The results suggest that the inhibitory effect of diazepam on ventricular automaticity results from the inhibition of adenosine uptake.