Organometallic formate complexes of platinum(II)

The compounds trans-[Pt(OCHO)R(PPh₃)₂] (R = C₆Cl₅; 2,3,4,6-C₆HCl₄; 2,3,4,5-C₆HCl₄; 2,5-C₆H₃Cl₂) have been prepared by treatment of [PtIR(PPh₃)₂] with AgClO₄ followed by reaction with NaOCHO in methanol. The cis isomers have been obtained by the direct reaction of HCO₂H with compounds containing PtHg bonds. For these and the analogous compounds containing C₆F₅ ligands, the dependence of J(³¹P¹⁹⁵Pt) on R has been studied, and the effects of cis-R shown to be in the opposite direction from those of trans-R ligands.     

Demercuriation reactions of the complexes [(PPh3)2RPtHgR′] containing platinum-mercury bonds

The compounds [(PPh₃)₂,RPtHgR′] (R = CH₃, R′= 2,5-C₆H₃Cl₂, 2,3,4- and 2,4,6-C₆H₂Cl₃, 2,3,4,5-, 2,3,4,6- and 2,3,5,6-C₆HCl₄, C₆Cl₅; R = Et, R′ = 2,5-C₆H₃Cl₂, 2,4,6-C₆H₂Cl₃; R = 2-C₆H₄Cl, R′=2-C₆H₄(CH₃)) have been prepared by the reactions of RHgR′ with Pt(PPh₃)₃, in order to study their possible use as intermediates in the preparation of diorganoplatinum complexes with different organic ligands. The dependence of J(³¹P-¹⁹⁵Pt) on slight differences in the electronic character of the ligand R′ in the series of compounds [(PPh₃)₂(CH₃)Pt-HgR′] has been studied.     

Reactivity of polychlorophenylmercury compounds with 1,10-phenanthroline

The action of 1,10-phenanthroline (phen) on the THF solutions of RHgCl (R = 2,5-C₆H₃Cl₂; 2,3,4? and 2,4,6-C₆H₂Cl₃; 2,3,4,5?, 2,3,4,6?, and 2,3,5,6-C₄HCl₄ and C₆Cl₅) gives RHgCl (phen) when R contains two chlorine substituents in ortho (R = 2,4,6-C₆H₂Cl₃; 2,3,4,6?, and 2,3,5,6-C₆HCl₄ and C₆Cl₅), but the symmetrisation reaction occurs when R = 2,5-C₆H₃Cl₂; 2,3,4-C₆H₂Cl₃ and 2,3,4,5-C₆HCl₄. The action of phen on HgR₂ only gives HgR₂ (phen) when R = 2,3,4,5-C₆HCl₄. Compounds of the type RHgMe do not react with phen. These results indicate that steric citects are as important as the electronegativity of R in the formation of tetracoordinated mercury compounds.     

Polychlorophenyl-platinum(II) complexes containing triphenylphosphine

A new method to prepare compounds of the type trans-[PtCl(R)(PPh₃)₂] (R = C₆H₅; 2,5-C₆H₃Cl₂; 2,3,4-, and 2,4,6-C₆H₂Cl₃; 2,3,4,5-, 2,3,4,6- and 2,3,5,6-C₆HCl₄ and C₆Cl₅) by reaction of cis-[PtCl₂(PPh₃)₂] and HgR₂ in the molten state is described.The reactions of the complexes with HCl, Cl₂ and I₂ have been examined in order to give information about the relative ease of cleavage of the various Ptaryl bonds. The replacement of Cl by NCS suggests an associative mechanism even for the complexes in which the polychlorophenyl ligand has chlorine atoms in both ortho positions.     

Chlorinated organic derivatives containing MoHg and WHg bonds: Importance of the steric effects in their stabilization

A series of MoHg and WHg bonded complexes [RHgM(CO)₃Cp], (R = 2,4,6-C₆H₂Cl₃,2,3,5,6-C₆,HCl₄ and C₆Cl₅) have been prepared from ClHgR and the salts Na[M(CO)₃)Cp]. When R contains only one ortho chlorine atom (R = 2,5-C₆H₃Cl₂, 2,3,4-C₆H₂Cl₃ and 2,3,4,5-C₆HCl₄) a symmetrisation process occurs to give the corresponding HgR₂ and Hg[M(CO)₃Cp)₂2. These results indicate that steric effects are very important in the formation of compounds containing molybdenum- or tungsten—mercury bonds. Complexes of the type [(C₆Cl₅)HgM(CO)₂(PPh₃)Cp] (M = Mo and W) are obtained from [(C₆Cl₅)HgM(CO)₃Cp] and PPh₃ in boiling ethanol.     

Synthesis and phosphorus 31 n.m.r studies of neutral and cationic compounds with platinum-mercury bonds

Summary The preparation and properties of the following neutral and cationic compounds containing Pt-Hg bonds is described: [(PPh₃)₂ClPt-HgR] (R=2,4,6-C₆H₂Cl₃; 2,3,4,6- and 2,3,5,6-C₆HCl₄ and C₆Cl₅), and [(PPh₃)₂LPt-Hg(C₆Cl₅)]ClO₄ (L=pyridine, , and -picoline; 2,4-lutidine and -colidine). All the compounds have been characterized by³¹P n.m.r. spectroscopy. The dependence of P, J(³¹P-¹⁹⁵Pt) and²J(³¹P-¹⁹⁹Hg) on the slight changes of the electronic properties of the ligands L and R has been studied.     

Cyclopentadienyl titanium complexes with aryldiazenido- or phosphiniminato-ligands

[Ti(η⁵-C₅H₅)Cl₃] reacts with Me₃SiNNPh to give [Ti(η⁵-C₅H₅)Cl₂(N₂Ph)], and this gives [Ti(η⁵-C₅H₅)₂Cl(N₂Ph)] on treatment with sodium cyclopentadienide in THF at ?80°C. [Ti(η⁵-C₅H₄R)Cl₃] (R  H, Me) reacts analogously with Me₃SiNPR₃ (PR₃  PPh₃, PPh₂Me) to give [Ti(η⁵-C₅H₄R)Cl₂(NPR₃)]. Under similar conditions TiCl₄ gives [TiCl₄(Me₃SiNPR₃)].     

The platinum—carbon bond strength in Pt(PPh3)2(Cl)(CPhCHPh)

The enthalpies of the reactions 1 and 2 have been determined as ΔH = Pt(PPh₃)₂(CPhCPh)_cryst. + HCl_g → Pt(PPh₃)₂(Cl)(CPhCHPh)_cryst. (1) Pt(PPh₃)₂(CPhCPh)_cryst. + 2HCl_g → cis-Pt(PPh₃)₂Cl_2cryst. + trans-CHPhCHPh_g (2) ?90.2 ± 6 and ΔH = ?139.0 ± 16 kJ mol^?1, respectively; dissociation energies of bonds involving platinum are expressed by the relationship: 41 kJ mol^?1 + D(Pt-tolane) = 2D(PtCPhCHPh) = {D₁(PtCl) + D₂(PtCl)} ?350 kJ mol^?1     

Decomposition reactions of square-planar bis-aryl-cobalt(II) complexes

The organocobalt complexes [CoR₂L₂], with (a) L = PEtPh₂ and R = 2,3,5,6- C₆HCl₄, 2,4,6-C₆H₂Cl₃ and 2,6-C₆H₃Cl₂; and (b) R = 2,4,6-C₆H₂Cl₃ and L = PEt₃, PEt₂Ph, $\text{1}\text{2}$ dpe, 3,5-lut and $\text{1}\text{2}$ bipy, have been obtained by reaction of RMgX with [CoCl₂L₂] or by ligand exchange from [CoR₂(PEtPh₂)₂]. The decompositions in benzene and carbon tetrachloride, and under oxidative conditions have been studied. In benzene solutions, the stability decreases with decrease in the number of chlorine atoms in R. A mixture of RH and RR is obtained in a ratio which depends on the nature of L, the configuration of the complex, and the presence of oxidants. The thermal decomposition takes place through a tricoordinate intermediate “CoR₂L”, when L = phosphine, or directly from [CoR₂L₂] when L = amine. The oxidatively induced decomposition takes place through a cobalt(III) intermediate, which gives RR when L = phosphine or RX (X = H, Br) when L = amine. The process is intramolecular in all cases.     

Preparation and properties of new ferrocenyl heterobimetallic complexes with counterion dependent NLO responses

New ferrocenyl-based bimetallic cationic compounds of the type of (E)-[CpFe(η⁵-C₅H₄)(CHCH)(C₆H₄)CNRuCp(PPh₃)₂]X (X=PF₆, BF₄) and of (E)-[CpFe(η⁵-C₅H₄)(CHCH)(C₆H₄)CNFeCp(CO)₂]PF₆ have been obtained and characterized. The crystal structure of (E)-[CpFe(η⁵-C₅H₄)(CHCH)(C₆H₄)CNRuCp(PPh₃)₂]BF₄ has been established by means of X-ray diffractometry. The NLO responses of the compounds have been studied by the hyper-Rayleigh scattering technique and the hyperpolarizability is found to be dependent on the nature of the counterion.     

Fulvene—platinum complexes: x-ray crystal structure of [Pt(η2-C5H4CPh2)(PPh3)2]

Bis(cycloocta-1,5-diene)platinum reacts with 2,3,4,5-tetraphenylfulvene to afford the complex [Pt(η²-CH₂C₅Ph₄)(cod)] (cod  C₈H₁₂) in which the metal atom is coordinated to the exo-cyclic double bond of the fulvene. Related compounds [Pt(η²-CH₂C₅Ph₄L₂] (L  PPh₃, PMePh₂, PMe₂Ph, AsPh₃ or CNBu^t have also been prepared and characterised. Reaction of the complexes [Pt(C₂H₄)₂(L)] (L  P(cyclo-C₆H₁₁)₃, PPh₃ or AsPh₃) with 2,3,4,5-tetraphenylfulvene yields the compounds [Pt(C₂H₄)(η²-CH₂C₅PH₄)(L)]. NMR data for the new species are reported and discussed. 6,6-Diphenylfulvene reacts with [Pt(cod)₂] and PPh₃ ($\text{1}\text{2}$ mol ratio) to give the complex [Pt(η²-C₅H₄CPh₂)-(PPh₃)₂] in which the metal atom is bonded to carbon atoms C(2) and C(3) of the fulvene ring. This was established by an X-ray diffraction study. Crystals are monoclinic, space group P2₁/n, with Z  4 in a unit cell of dimensions a  13.761(4), b  21.653(13), c  17.395(6) Å, β,  104.46(2)°. The structure has been solved and refined to R  0.064 (R′  0.064) for 3139 independent diffracted intensifies measured at room temperature. The platinum atom is in a trigonal environment formed by the two ligated phosphorus atoms and the CC bond of the fulvene which is elongated to 1.52(3) Å. The c₅ fulvene ring is planar, and makes an angle of 108° with the coordination plane around the platinum. In this plane the metal atom is slightly asymmetrically bonded with PtC 2.15(2) and 2.24(2) Å, and PtP 2.280(6) and 2.301(6) Å.     

Derivate des borols: IX. (η5-borol)metall-komplexe von ruthenium,osmium und rhodium

Dehydrogenating complexation of borolenes with carbonyls (Ru₃(CO)₁₂, Os₃(CO)₁₂), Wilkinson's catalyst (RhCl(PPh₃)₃) and related compounds (RuCl₂(PPh₃)₃, RuHCl(PPh₃)₃, OSCl₂(PPh₃)₃), and (η⁶-arene)ruthenium complexes (Ru(η-C₆H₆)(η⁴-C₆H₈), [Ru(η-C₆H₆)Cl₂]₂, [Ru(η-C₆-Me₆)Cl₂]₂) leads to the (η⁵-borole)metal complexes of Ru, Os, and Rh. Inter alia, the preparation of the complexes Ru(CO)₃(η⁵-C₄H₄BF) (R = Ph, OMe, Me), Os(CO)₃L (L = η⁵-C₄H₄BPh), MHClL(PPh₃)₂ (M = Ru, Os), RhClL(PPh₃)₂, and RuL(η-C₆R₆) (R = H, Me) is described. The structures of RuHClL(PPh₃)₂ and RhClL(PPh₃)₂ have been determined by X-ray diffraction analysis.     

The cleavage of SiC bonds by transition metal compounds. Methylation and phenylation of olefins by organosilicon compounds in the presence of palladium salts

Palladium(II)compounds are able to cleave SiR bonds in various alkyl- and aryl-silanes, and linear and cyclic siloxanes and silazanes at 60–120°. The Group VIII metals and metal compounds PdCl₂, H₂PtCl₆, H₂PtCl₆ + SnCl₂, Pt(PPh₃)₃, Pt(PPh₃)₄, Pt/C and Pd catalyse the cleavage of the SiMe bond in hexamethyldisiloxane at 100–200° to give linear trisiloxane as the main product. This reaction which involves the transfer of methyl or phenyl groups from the Si to the Pd atom, can be used for methylation and phenylation of olefins by organosilicon compounds.     

Synthesis and redistribution reactions of asymmetric σ-arylplatinum(II) complexes containing 4,7-phenanthroline

The mononuclear σ-aryl complexes of the type trans-[Pt(σ-C₆H₄R)(4,7-phen)(PPh₃)₂]OTf (R=4-CO₂Si^tBuPh₂, 4-CONHMe, 3-CO₂Si^tBuPh₂, 3-CONHMe; OTf=trifluoromethanesulfonate) containing a monodentate 4,7-phenanthroline (4,7-phen) ligand were prepared by an oxidative addition reaction of an aryl iodide with Pt(PPh₃)₄ to yield the key iodoplatinum(II) precursors trans-[PtI(σ-C₆H₄R)(PPh₃)₂], followed by halogen metathesis with one equivalent of 4,7-phen. The reaction of trans-[Pt(σ-C₆H₄R)(4,7-phen)(PPh₃)₂]OTf with labile complexes of the type trans-[Pt(OTf)L₂(σ-C₆H₄R′)] (L=PEt₃, R′=H; L=PPh₃, R′=4-CO₂Si^tBuPh₂, 3-CO₂Si^tBuPh₂, 3-CONHMe) afforded the asymmetric dinuclear complexes of the type trans-[Pt(σ-C₆H₄R)L₂(μ-4,7-phen)Pt(σ-C₆H₄R′)L′₂](OTf) ₂ (L=PPh₃, R=4-CO₂Si^tBuPh₂, L′=PEt₃, R′=H; L=L′=PPh₃, R=4-CONHMe, R′=4-CO₂Si^tBuPh₂; R=4-CO₂Si^tBuPh₂, R′=3-CONHMe; R=3-CONHMe, R′=3-CO₂Si^tBuPh₂) in which the 4,7-phen acts as a bridging bidentate ligand. The novel dinuclear species undergo an unusual redistribution reaction that is essentially thermoneutral at 298 K. The exchange process involves facile cleavage of a Pt-N bond and the rapid exchange of trans-[PtL₂(σ-aryl)] units in the equilibrium mixture.     

ortho-, meta- and para-nitrophenylgold(I) complexes

Treatment of [BzPh₃P][AuCl₂] with [Hg(x-C₆H₄NO₂)₂] (x = o, m, or p) gives anionic gold(I) complexes of the type [BzPh₃P][Au(R)Cl](R = o-, m- or p-C₆H₄NO₂, Bz = C₆H₅CH₂). The chloro ligand in [Au(o-C₆H₄NO₂)Cl]^? can be replaced by bromo or iodo ligands by use of NaBr or NaI. The anions [Au(R)Cl]^? react with neutral monodentate ligands, L, to give neutral mononuclear complexes [Au(R)L] (R = o-C₆H₄NO₂, L = PPh₃, AsPh₃; R = m-C₆H₄NO₂, L = PPh₃) and with 1,2-bis(diphenylphosphino)ethane (dpe) to give [Au₂(R)₂(dpe)] (R = o-C₆H₄NO₂). The corresponding [Au(p-C₆H₄NO₂)Cl]^? reacts with PPh₃ or AsPh₃ to give mixtures containing [AuClL]. The anionic ortho-nitrophenylgold(I) complex is much more stable than its meta- or para-nitrophenyl isomers. These are thought to be the first reports of nitrophenylgold(I) complexes.     

Syntheses of σ-cyclobut-1-en-3-onyl complexes by cycloaddition of ketenes to some transition metal alkynyl complexes

Reactions of ketenes (R¹R²CCO) with (η⁵-C₅H₅)Ni(PPh₃)CCR (I) and (η⁵-C₅H₅)Fe(CO)(L)CCR (III, L = CO and PPh₃) give σ-cyclobut-1-en-3-onyl complexes, {(η⁵-C₅H₅)Ni(PPh₃)$\text{CC(R)COC}$}R¹R² (VI) and (η⁵-C₅H₅)Fe(CO)(L)$\text{CC(R)COC}$R¹R² (IX)}, (2 + 2) cycloaddition products, in good yields. The σ-cyclobutenonyl complexes also can be prepared by the reaction of I and III with acyl chlorides in the presence of triethylamine.     

Bi- and tetranuclear polyfluorophenyl-bridged gold(I) complexes

The reaction of RAuL (R = 2,4,6-C₆F₃H₂, 3,6-C₆F₂H₃, 4-C₆FH₄ or 3-CF₃C₆H₄; L = PPh₃ or AsPh₃) or RAudpeAuR with inorganic acids HA (A = ClO₄, BF₄ or PF₆) leads to binuclear complexes of the types [R(AuL)₂]A or [R(Au₂dpe)]BF₄. Similarly, reaction of NBu₄[Au(2,4,6-C₆F₃H₂)₂] with HPF₆ yields the tetranuclear complex Au₄(2,4,6-C₆F₃H₂)₄. Addition of RAuL to solutions obtained by treating ClAuL with AgA also gives compounds of the type [R(AuL)₂]A.     

Carbonyl rhodium(I) complexes with α-diimines ligands

The reactions of [Rh(CO)₂Cl]₂ with α-diimines, RN=CR′-CR′=NR (R = c-Hex, C₆H₅, p-C₆H₄OH, p-C₆H₄CH₃, p-C₆H₄OCH₃, R′ = H; R = c-Hex, C₆H₅, p-C₆H₄OH, p-C₆H₄OCH₃; R′ = Me) in 2:1 Rh/R-dim ratio gave rise to ionic compounds [(CO)₂Rh.R-dim(R′,R′)][Rh(CO)₂Cl₂] which have been characterized by elemental analyses, electrical conductivity, ¹H-NMR and electronic and IR spectroscopy. Some of these complexes must involve some kind of metal-metal interaction. The complex [Rh(CO)₂Cl.c-Hex-dim(H,H)] has been obtained by reaction of [Rh(CO)₂Cl]₂ with the c-Hex-dim(H,H) ligand in 1:1 Rh/R-dim ratio. The reactions between [(CO)₂Rh.R-dim(H,H)][Rh(CO)₂Cl₂](R = c-Hex or p-C₆H₄OCH₃) with the dppe ligand have been studied. The known complex RhCl(CO)(PPh₃)₂ has been isolated from the reaction of [(CO)₂Rh.R-dim(H,H)]-[Rh(CO)₂Cl₂] (R = c-Hex or p-C₆H₄OCH₃) with PPh₃ ligand.     

Gold(I) and gold(III) ortho-nitrophenyl complexes. Crystal and molecular structure of ortho-nitrophenyltriphenylarsinegold(I)

The reaction between [Au(o-C₆H₄NO₂)Cl]⁻ and tetrahydrothiophene (tht) in the presence of NaClO₄ give a solution (probably containing [Au(o-C₆H₄NO₂)(tht)]) that can be used to prepare neutral [Au(o-C₆H₄NO₂)L_n] (L = AsPh₃, n = 1; L = SbPh₃, n = 2; L = 1,10-phenanthroline, n = 1) or anionic [Au(o-C₆H₄-NO₂(CN)]⁻ complexes. Treatment of [Au(o-C₆H₄NO₂)(PPh₃)] with chlorine or PhICl₂ gives trans- or cis-[Au(o-C₆H₄NO₂)Cl₂(PPh₃)]. Isomerizations occur when the cis-isomer is treated with concentrated solutions of chlorine or when the trans-isomer is heated.An X-ray diffraction study of [Au(o-C₆H₄NO₂)(AsPh₃)] has revealed an almost linear coordination around the gold atom (AsAuC mean value 177(2)°). The AuO distance is too long (mean value 2.80(3) Å) for intramolecular coordination.     

New η-allyl η-cyclopentadienylcobalt cations

[Co(R-η-C₃H₄)(η-C₅H₅)I] is a good precursor for the preparation of some new cationic complexes as the iodide can easily be replaced; thus addition of PEt₃ to the iodo-complex (R  H) gives [Co(η-C₃H₅)(η-C₅H₅)(PEt₃)]⁺. The reactions of [Co(R-η-C₃H₄)(η-C₅H₅))I] (R  H or 2-Me) with AgBF₄ give solutions containing the coordinatively unsaturated species [Co(R-η-C₃H₄)(η-C₅H₅)⁺. The presence of traces of water leads to the formation of [Co(R-ηC₃H₄)-(η-C₅H₅)(H₂O)]⁺. The addition of monodentate ligands L  PEt₃ PPh₃, AsPh₃, SbPh₃, CNCH₃ and bidentate ligands LL  Ph₂PCH₂CH₂PPh₂(dppe) and o-C₆H₄(AsMe₂)₂(diars), gives, respectively mononuclear [Co(2-Me-ηC₃H₄)-(η-C₅H₅)L]⁺ and binuclear ligand-bridged [(2-Me-ηC₃H₄)(η-C₅H₅)CoLLCo(2-Me-ηC₃H₄)(η-C₅H₅))]²⁺ complexes. Crystals of [Co(2-Me-ηC₃H₄)(η-C₅H₅)-(H₂O)]⁺[BF₄]^- are monoclinic, space group P2₁/c, with a 7.858(3), b 10.262(4), c 15.078(4) Å, β 98.36(1)°. The molecular structure contains the cobalt atom bonded to planar 2-Me-allyl and cyclopentadienyl substituents, which are almost parallel with the H₂O molecule in a staggered conformation with respect to the 2-Me group.