Milagros Tomás

Mono- and bi-nuclear anionic pentafluorophenyl complexes of palladium(II) and platinum(II)

The arylation of K2[MCl4], [MCl2(tht)2], MCl2, or [NBu4]2[M2(µ-Br)2Br4](M = Pd or Pt; tht = tetrahydrothiophen) with LiR or MgBrR (R = C6F5) leads to novel mono- and bi-nuclear anionic organo-derivatives of the general formulae [MR3(tht)]–, [MR4]2–, and [M2(µ-Br)2R4]2–, which have been isolated as tetra-alkylammonium salts. Reaction of compounds of the [MR3(tht)]– type with neutral ligands leads to the substitution of tht by L, that of [PdR4]2– with PdCl2 gives rise to the formation of [Pd2(µ-Cl)2R4]2–, whilst [M2(µ-X)2R4]2– reacts with alkali-metal salts of Br–, I–, or SCN– to give (without cleavage of the bridging system) the corresponding complexes. Twenty anionic complexes of these three novel types have been isolated and characterized.

Polynuclear platinum–silver, –copper, and –gold acetylide complexes. Molecular structure of [Pt2Ag4(CCBut)8]

Hexanuclear complexes [Pt2Ag4(CCR)8] [R = Ph (1) or But (2)] have been obtained by treating [PtCl2(tht)2] (tht = tetrahydrothiophene) with [Ag(CCR)]n(Pt/Ag 1 : 4). The complexes [Pt2M4(CCR)8] [M = Cu, R = Ph (3) or But (4); M = Au, R = But (5)] were obtained from [Pt2Ag4(CCR)8] with CuCl or [AuCl(tht)] respectively. Alternatively, the reactions between [NBu4]2[Pt(CCR)4] and AgClO4, CuCl–NaClO4, or [AuCl(tht)]–NaClO4 yield respectively complexes (1)–(5). The molecular structure of [Pt2Ag4(CCBut)8] has been determined by an X-ray diffraction study: monoclinic, space group C2 with a = 37.062(7), b = 12.0223(16), c = 20.459(3) A, β = 107.485(15)°, Z = 6, R 0.0416, R′ 0.0465 for 5 613 reflections with F > 6σ(F). The six metal atoms are arranged in a slightly irregular octahedron with the platinum atoms mutually trans and the silver atoms in the equatorial plane, with Pt ⋯ Ag and Ag ⋯ Ag distances longer than 3.0 A. Each platinum atom is in an almost square-planar environment formed by four CCBut ligands. Each acetylenic fragment also forms an asymmetric π interaction with one silver atom of the equatorial positions so that each silver atom is bonded to two acetylenic fragments, of two different Pt(CCBut), moieties. These moieties of each [Pt2Ag4(CCBut)8] unit are staggered.

Tris(pentafluorophenyl)platinate(II) complexes

(NBu4)2[Pt(C6F5)4] reacts with HCl to give 11 (NBu4)2[PtCl(C6F5)3] or 12 (NBu4)2[Pt2(μ-Cl)2)(C6F5)4]. Metathetical reactions of the mononuclear PPN salt (PPN/Ph3PNPPh3) with KX (X = Br, I, CN or SCN) give complexes of the formula (PPN)2[PtX(C6F5)3], whereas reactions with neutral ligands in the presence of a perchlorate MClO4 lead to derivatives of the types Q[Pt(C6F5)3L] (L = C2Ph2, dpm or dpe) and Q2[(C6F5)3Pt(L-L)Pt(C6F5)3] (L = dpm or dpe). The reactions of Q[Pt(C6F5)3(dpm)] with (O3ClO)Pd(C6F5)(PPh3)2, PdCl2(tht)2, PtCl2(tht)2 or AgClO4 give bi- or tri-nuclear derivatives.

Reversible single-crystal-to-single-crystal cross-linking of a ribbon of cobalt citrate cubanes to form a 2D net.

An unprecedented 1-D polymer of cobalt citrate cubanes, 1, has been prepared by wet chemistry techniques and isolated as single crystals with two units of formula Cs2Co7(citr)4(H2O)21 in the unit cell [H4citr = C6H8O7, citric acid], as characterized by X-ray diffraction at T = 278 K. In addition to the four Co atoms in the cubane unit, there are four independent peripheral citrate-bound Co sites. Upon warming at T = 303 K, the polymer undergoes cross-linking through a complex substitution/addition reaction at one of the peripheral Co centers to produce a new 2-D polymer based on the same Co citrate cubane building block. In the transition a second peripheral Co atom undergoes a substitution reaction and separates from the polymer. The new phase, 2, analyzed by X-ray diffraction from the same crystalline sample as 1, has two units of formula Cs2Co7(citr)4(H2O)13.5 in the unit cell. Water egress in the transition amounts to 35.7 mole percent. The volume of the unit cell diminishes by 12.4%. The Co center at...

Neutral and anionic binuclear perhalogenophenyl platinum–silver complexes with Pt→Ag bonds unsupported by covalent bridges. Molecular structures of [(tht)(C6Cl5)(C6F5)2-PtAg(PPh3)], [NBu4][(C6F5)4PtAg(tht)] and [NBu4][cis-(C6Cl5)2(C6F5)2PtAg(tht)](tht = tetrahydrothiophene)

Heterobinuclear complexes of general formula [L(C6Cl5)3-x(C6F5)xPtAg(PPh3)][x= 2–0; L = tht (tetrahydrothiophene), PPh3 or pyridine (py)]14–21 have been prepared by treating the anionic platinum derivatives [NBu4][PtL(C6F5)x(C6Cl5)3-x] with [Ag(OCIO3)(PPh3)](molar ratio 1 : 1) in dichloromethane. The anionic [NBu4][(C6F5)4PtAgL](L = OEt2, PPh3 or tht)22–24 and [NBu4][cis-(C6Cl5)2(C6F5)2PtAg(tht)]25 have been obtained from the corresponding [NBu4]2[Pt(C6X5)2(C6X′5)2] and [Ag(OCIO3)L](molar ratio 1 : 1) in CH2Cl2–diethyl ether. The reaction between [NBu4][Pd(C6F5)3(tht)] and [Ag(OCIO3)(PPh3)] renders Ag(C6F5) and cis-[Pd(C6F5)2(PPh3)(tht)]. The salts [NBu4]2[Pt(C6Cl5)4] and [NBu4]2[Pd(C6F5)4] react with [Ag(OCIO3)(tht)] yielding [NBu4][Pt(C6Cl5)3(tht)] and [NBu4][Pd(C6F5)3(tht)], respectively. The reactions between [NBu4]2[Pt(C6F5)4] and [Ag(OCIO3)(tht)] or [Ag(OCIO3)(PPh3)](molar ratio 1:2) render in the first case complex 24 while in the second an unstable material which evolves to [(Ph3P)(C6F5)3PtAg(PPh3)]27 is obtained. The reaction between [NBu4]2[trans-PtCl2(C6X5)2](X = F or Cl) and [Ag(OCIO3)(tht)] or [Ag(tht)2]ClO4 have also been studied. The structures of [(tht)(C6Cl5)(C6F5)2PtAg(PPh3)]14, [NBu4][(C6F5)4PtAg(tht)]24 and [NBu4][cis-(C6Cl5)2PtAg(tht)]25 have been established by single-crystal X-ray diffraction studies. The complexes contain a strong Pt→Ag bond [2.650(2), 14; 2.641(1), 24; and 2.692(2)A, 25] unsupported by covalent bridges, and short contacts between the o-F or o-Cl atoms of the C6X5(X = F or Cl) groups and the Ag atom are present. The relative strength of such contacts is discussed. Methods for the synthesis of mixed pentachloro-pentafluoro-phenyl starting complexes 1–13 have been investigated.

Synthesis, molecular structure (M = Pd, X = OH) and reactivity of trinuclear asymmetric complexes [(C6F5)2Pt(µ-PPh2)2M(µ-X)2Pt(PPh3)2](M = Pd or Pt; X = Cl or OH)

The tetranuclear complexes [NBu4]2[(C6F5)2Pt(µ-PPh2)2M(µ-CI)2M(µ-PPh2)2Pt(C6F5)2](M = Pd or Pt) reacted with AgCIO4 and cis-[PtCl2(PPh3)2] in dichloromethane–acetone affording the neutral homo- or hetero-metallic asymmetric species [(C6F5)2Pt(µ-PPh2)2M(µ-CI)2Pt(PPh3)2]1 and 2. Treatment of their CH2CI2 solutions with KOH in methanol rendered the corresponding µ-hydroxo derivatives 3 and 4 which reacted with HX′(X′= Cl, Br, SPh, NHC6H4Me-p or PPh2) to afford [(C6F5)2Pt(µ-PPh2)2M(µ-X)(µ-X′)Pt(PPh3)2](X = X′= Cl 1, 2; Br 5, 6; SPh 7, 8; X = OH, X′= NHC6H4Me-p9, 10; X = OH, X′= PPh211, 12). The structure of 3 has been determined by single-crystal X-ray diffraction.

Synthesis and reactivity of binuclear homo- or hetero-metallic complexes [NBu4]2[MM′(µ-C6F5)2(C6F5)4](M = M′= Pd or Pt; M = Pt, M′= Pd) with bridging pentafluorophenyl groups

By reacting [NBu4]2[M(C6F5)4] with cis-[M(C6F5)2(thf)2](M = Pd or Pt; thf = tetrahydrofuran) in CHCl3 the binuclear homo- or hetero-metallic complexes [NBu4]2[MM′(µ-C6F5)2(C6F5)4](M = M′= Pd or Pt; M = Pt, M′= Pd), containing bridging pentafluorophenyl groups, are obtained. Their structures have been established by 19F n.m.r. spectroscopy. The homometallic derivatives react with neutral (L) or anionic (X)– ligands yielding [NBu4][M(C6F5)3L](M = Pd or Pt; L = PPh3, CO, or ½Ph2PCH2PPh2) or [NBu4]2[MX(C6F5)3](M = Pd or Pt; X = Br), respectively. The heterometallic complex [NBu4]2[PdPt(µ-C6F5)2(C6F5)4] reacts with PPh3 or Ph2PCH2PPh2 giving rise to a mixture of cis-[Pd(C6F5)2L2] and [NBu4]2[Pt(C6F5)4], while its reaction with CO yields a mixture of [NBu4][Pt(C6F5)3(CO)] and [NBu4][Pd(C6F5)3(CO)].

The first mononuclear PtIII complex. Molecular structures of (NBu4)[PtIII(C6Cl5)4] and of its parent compound {NBu4}2[PtII(C6Cl5)4]·2CH2Cl2

(NBu4)[PtIII(C6Cl5)4], fully characterized by crystallographic, spectral, and magnetic measurements has been isolated by oxidation with halogens or TICl3 of the parent compound (NBu4)2[PtII(C6CL5)4], which has also been analysed by X-ray crystallography.

Synthesis, molecular structure and reactivity of cis-[Pd(C6F5)2(C6H5CH2NMe2-κC1, κN)] a compound displaying an unusual η1 arene–palladium interaction

The reaction between cis-[Pd(C6F5)2(thf)2](thf = tetrahydrofuran) and benzyldimethylamine rendered cis-[Pd(C6F5)2(C6H5CH2NMe2-κC1,κN)]1, a four-co-ordinate compound containing an unusual η1arene–palladium interaction with the benzyldimethylamine acting as a bidentate chelating ligand. Complex 1 reacts with acetone, acetonitrile, dimethyl sulfoxide or CO (L) to yield cis-[Pd(C6F5)2(NMe2CH2C6H5)(L)]2–5 respectively, which do not have a η1 arene–palladium interaction. The reaction of 1 with Br–or SPMe2Ph (L′)(molar ratio 1:1) produced the complete displacement of the amine and the formation of [(F5C6)2Pd(µ-L′)2Pd(C6F5)2]n–(n= 2 or 0), and with Cl–(molar ratio 1:1) a mixture of complexes is formed. The crystal structures of compounds 1and 2 have been determined.

Preparation of cis-bis-acetylene-bis(pentafluorophenyl)-palladium(II) and -platinum(II) complexes, crystal structure of cis-[Pt(C6F5)2 (PhCCPh)2]

Abstract Treatment of cis-[M(C6F5)2(THF)2] (M = Pd, Pt; THF = tetrahydrofuran) with PhCCPh has given the novel bis-acetylene-palladium(II) and -platinum(II) complexes cis-[M(C6F5)2(PhCCPh)2]; these are stable even though there seems to be no significant π-back bonding according to the X-ray structure of the platinum complex.