Palladium(II) and platinum(II) complexes of rhodanine and 3-methylrhodanine

Summary The following palladium(II) and platinum(ll) complexes of rhodanine (HRd) and 3-methylrhodanine (MRd) have been prepared: Pd(HRd)_1.5Cl₂, Pd(HRd)₂Br₂, Pd(HRd)₂Br₂ · 0.25 EtOH, M(MRd)₂X₂ [M = Pd, X = Cl (0.25 EtOH) or Br; M = Pt, X = Cl or Br], Pd(MRd)₃Br₂, and M(MRd)₄(ClO₄)₂ (M = Pd or Pt). The ligands are coordinated to the metal through the thiocarbonylic sulphur atom. Pd(HRd)_1.5Cl₂ has presumably a structure such as (X = Cl or Br) complexes have a trans-planar coordination. Pd(MRd)₂X₂ (X = Cl or Br) complexes arecis-planar coordinated. Pd(MRd)₃Br₂ has presumably a square coordination with two MRd molecules and two CI ionscis-coordinated in the equatorial plane, and a MRd molecule and a Cl ion weakly bonded in apical position. The M(MRd)₄(ClO₄)₂ complexes have square planar coordination.Author to whom all correspondence should be addressed.     

Mixed ligand complexes with 2-piperidine-carboxylic acid as primary ligand and ethylene diamine, 2,2′-bipyridyl, 1,10-phenanthroline and 2(2′-pyridyl)quinoxaline as secondary ligands: preparation,characterization and biological activity

Synthesis procedures are described for the new stable mixed ligand complexes, [Pd(Hpa)(pa)]Cl, [Pd(pa)(H₂O)₂]Cl, [Pd(pa)(en)]Cl, [Pd(pa)(bpy)]Cl, [Pd(pa)(phen)Cl], [Pd(pa)(pyq)Cl], cis-[MoO₂(pa)₂], [Ag(pa)(bpy)], [Ag(pa)(pyq)], trans-[UO₂(pa)(pyq)](BPh₄) and [ReO(PPh₃)(pa)₂]Cl (Hpa = 2-piperidine-carboxylic acid, en = ethylene diamine, bpy = 2,2′-bipyridyl, phen = 1,10-phenanthroline, pyq = 2(2′-pyridyl)quinoxaline). Their elemental analyses, conductance, thermal measurements, Raman, IR, electronic, ¹H-n.m.r. and mass spectra have been measured and discussed. 2-Piperidine-carboxylic acid and its palladium complexes have been tested as growth inhibitors against Ehrlich ascites tumour cells (EAC) in Swiss albino mice.     

Complexes of palladium(II) and platinum(II) with 2-hydrazinopyridine and 8-hydrazinoquinoline

The square planar complexes cis-[MCl₂(hypy)], cis-[MCl₂(hyqu)], [Pt(hypy)₂] [PtCl₄], [Pd(hypy)₂][ClO₄]₂ and [Pd(hyqu)₂][ClO₄]₂ (M = Pd or Pt, hypy = 2-hydrazinopyridine, hyqu = 8-hydrazinoquinoline), in which hypy and hyqu act as bidentate chelating ligands, have been prepared and characterized. Complexes containing hyqu do not appear to have been isolated previously.     

Neutral and cationic orthopalladated ( ) complexes ( = phenylazophenyl, dimethylbenzylamine, 8-methylquinoline, 2-methoxy-3-N,N-dimetrylaminopropyl)

By reacting [Pd( )(μ-Cl)]₂ with AgClO₄ in NCMe, the corresponding cationic complexes [Pd( )(NCMe)₂]ClO₄ ( = phenylazophenyl-C²,N¹; dimethylbenzylamine-C²,N; 8-methylquinoline-C⁸,N) can be obtained. Solutions containing the cations [Pd( )(S)₂]⁺ are obtained when the reaction is carried out in tetrahydrofuran or acetone (S). The treatment of these solutions with bidentate ligands (L—L) (Ph₂PCH₂PPh₂,Ph₂PNHPPh₂ or Ph₂PCH₂PPh₂CHC(O)Ph) gives the mononuclear [Pd( )(L3l)]ClO₄ complexes, with L3l acting as a chelate ligand. On the other hand [Pd( (μ-Cl)]₂ reacts with L3l (Ph₂PCH₂PPh₂, Ph₂PNHPPh₂) yielding [Pd( )Cl(L3l)] with L3l acting as monodentate. The reactions between [Pd( )(NCMe)₂]ClO₄ and 2,2′-bipyrimidyl give rise to the formation of the mononuclear [Pd( ) (bipym)]ClO₄ or binuclear [Pd₂( )₂(μ-bipym)](ClO₄)₂, [( )Pd(μ-bipym)Pd( )](ClO₄)₂ derivatives. Finally [Pd( )Cldppm] (dppm = Ph₂PCH₂PPh₂) react with NaH producing the neutral complexes [Pd( )(ddppm)] (ddppm = Ph₂PCHPPh₂) which by reaction with HCl lead again to the starting materials [Pd( )Cl(dppm)].     

Factors determining the chemoselectivity of phosphorus-modified palladium catalysts in the hydrogenation of chloronitrobenzenes

The precursor nature effect on the state of the Pd–P surface layer in palladium catalysts and on their properties in the liquid-phase hydrogenation of chloronitrobenzenes under mild conditions has been investigated. A general feature of the Pd–P-containing nanoparticles obtained from different precursors and white phosphorus at P/Pd = 0.3 (PdCl₂ precursor) and 0.7 (Pd(acac)₂ precursor) is that their surface contains palladium in phosphide form (BE(Pd3d _5/2) = 336.2 eV and BE(Р2р) = 128.9 eV) and Pd(0) clusters (BE(Pd3d_5/2) = 335.7 eV). Factors having an effect on the chemoselectivity of the palladium catalysts in chloronitrobenzenes hydrogenation are considered, including the formation of small palladium clusters responsible for hydrogenation under mild conditions.     

Synthesis and characterization of 1-Methyl-4-mercaptopiperidine complexes of nickel(II), palladium(II) and platinum(II)

Summary Complexes of formulae Ni(HRS)₂X₂ (X=Cl or Br), M(HRS)₂Y₂ (M=Ni or Pd; Y=NO₂ or C1O₄), Pd(HRS)X₂ (X=Cl, Br or I), Pt(HRS)X₂ (X=Cl or Br), Pt(HRS)₂(ClO₄)₂ and M(RS)₂ (M=Pd or Pt) where HRS and RS denote 1-methyl-4-mercaptopiperidine in the zwitterionic or in the thiolato form, respectively, have been prepared and characterized. In all the complexes the ligands are coordinated exclusively through sulphur. Polymeric structures consisting of square-planar geometry with sulphur-bridged metal atoms are proposed in each case.     

Synthesis,Crystal Structure and Stability Studies of Dithiocarbamate Complexes of Some Transition Elements (M=Co,Ni, Pd)

Single-crystal x-ray structure determinations have been recorded at 295 K for the dithiocarbamate metal compounds [Co(Et₂dtc)₃], [Co(nPr₂dtc)₃], [Pd(iPr₂dtc)₂] and [Pd(Et₂dtc)₂]. The stability constants(K) in EtOH of dialkyldithiocarbamate metal complexes [M(R₂dtc)_n] (M=Co, Ni, Pd. R=Me, Et, iPr, nPr. n=2, 3. dtc=dithiocarbamate) are determined by UV-vis data. The stability of the metal complexes increases in the order: Co<Ni<Pd. The effects of alkyl groups on the stability of [M(R₂dtc)₂] (M=Ni and Pd) increase in the order: Me<Et<nPr<iPr, and [Co(R₂dtc)₃] decrease in the order: Et>iPr>nPr>Me. The results obtained from this study confirm that the stability due to alkyl groups may be partly attributed to changes in the residual positive charge and also partly to steric hindrance of branched alkyl-groups. The comparison between the solid and solution states shows that the [M(R₂dtc)₂] (M=Pd, Ni) complexes have similar changes in M-S distance and stability with change in alkyl group. [M(iPr₂dtc)₂] has the shortest M-S distance and the highest stability in solution.     

Palladium(0) complexes coordinated with substituted olefins and tertiary phosphine ligands

New palladium(0) complexes with a variety of coordinated olefins [Pd(olefin)(PMePh₂)₂] (II) (olefin = styrene, ethyl methacrylate, methyl methacrylate, methyl acrylate, methacrylonitrile, and dimethyl maleate), were prepared by the reactions of [PdEt₂(PMePh₂)₂] (I) with corresponding olefins in toluene. These complexes were characterized by means of elemental analysis, IR and ¹H NMR spectroscopy and the chemical reactions. The dissociation of the coordinated olefin from complex II in solution was confirmed by spectroscopic studies of [Pd(mma)(PMePh₂)₂] (mma = methyl methacrylate). From the variable temperature NMR study, kinetic parameters for the dissociation process were determined as E_a = 7 kcal/mol, and ΔS³ (293 K) = -30 cal/deg · mol. Some new hydrido complexes, [Pd(H)ClL₂] (IV) (L = PMePh₂, PEtPh₂ and PEt₂Ph), were prepared by the reactions of [Pd(olefin)L₂] with dry HCl.     

Synthesis, structure, and electroconductivity of new radical cation salt [Pd(dddt)2]2GaBr4

A new radical cation salt based on the dithiolate complex Pd(dddt)₂ (dddt=5,6-dihydro-1,4-dithiine-2,3-dithiolate) with the tetrahedral anion [GaBr₄]^? was synthesized. The crystal and molecular structure was determined by XRD analysis. The crystal structure of the salt contains Pd(dddt)₂ cation layers alternating with layers of [GaBr₄]^? anions along thec axis of the unit cell. The cation layers contain stacks of Pd(dddt)₂, with a Pd...Pd distance of 3.011 Å. The electroconductivity of [Pd(dddt)₂]₂GaBr₄, single crystals at room temperature is 0.25 Ohm^?1 cm^?1 and decreases with temperature decrease, the activation energy beingE _a=0.66 eV.     

Platinum(II) and Palladium(II) Bis(chelate) Complexes Containing both Tri(1‐cyclohepta‐2, 4, 6‐trienyl)phosphane,P(C7H7)3, and Dichalcogenolato Ligands

Tri(1‐cyclohepta‐2, 4, 6‐trienyl)phosphane, P(C₇H₇)₃ ([P] when coordinated to a metal atom), was used to stabilize complexes of platinum(II) and palladium(II) with chelating dichalcogenolato ligands as [P]M(E∩E) [E = S, ∩ = CH₂CH₂, M = Pt ( 3a ); E = S, ∩ = 1, 2‐C₆H₄, M = Pt ( 5a ), Pd ( 6a ); E = S, ∩ = C(O)C(O), M = Pt ( 7a ), Pd ( 8a ); E = S, Se, ∩ = 1, 2‐C₂(B₁₀H₁₀), M = Pt ( 9a, 9b ), Pd ( 10a, 10b ); E = S, ∩ = Fe₂(CO)₆, M = Pt ( 11a ), Pd ( 12a )]. Starting materials in all reactions were [P]MCl₂ with M = Pt ( 1 ) and Pd ( 2 ). Attempts at the synthesis of [P]M(ER)₂ with non‐chelating chalcogenolato ligands were not successful. All new complexes were characterized by multinuclear magnetic resonance spectroscopy in solution (¹H, ¹³C, ³¹P, ⁷⁷Se and ¹⁹⁵Pt NMR), and the molecular structures of 5a and 12a were determined by X‐ray analysis. Both in the solid state and in solution the ligand [P] is linked to the metal atom by the P‐M bond and by η²‐C=C coordination of the central C=C bond of one of the C₇H₇ rings. In solution, intramolecular exchange between coordinated and non‐coordinated C₇H₇ rings is observed, the exchange process being markedly faster in the case of M = Pd than for M = Pt.     

Structures, energy bands and conductivities of (Me3NEt)[Pd(dmit) 2]2 and (NEt4)[Pd(dmit) 2]2

The electrical conductive molecular crystals (Me₃NEt)[Pd(dmit) ₂]₂ and (NEt₄)[Pd (dmit) ₂]₂ (dmit = 4,5-dimercapto-1,3-dithiole-2-thione) have been prepared, and their crystal structures and conductivity-temperature curves have been determined. The fact that the conductivity at room temperature of (Me₃NEt)[Pd(dmit) ₂]₂ (σ = 58 Ω^-1 cm^-1) is much higher than that of (Net₄)-[Pd(dmit)₂]₂ (σ = 2.2 Ω^-1.cm^-1) has been rationally explained by the results of energy band calculations. (MeNEt₃)[Pd(dmit)₂]₂ belongs to monoclinic system, P2₁/m space group and (Net₄)[Pd (dmit)₂]₂ belongs to triclinic system, $P\bar 1$ space group. The structural conducting component of the crystals is the planar coordinative anion [Pd(dmit)₂]^0.5- which forms the face-to-face dimmer. [Pd(dmit)₂]^- ₂These dimers have been further constructed to be a kind of two-dimensional (2-D) conductive molecular sheet by means of S_S intermolecular interactions. The tiny difference of the above 2-D molecular sheets of the two title crystals has resulted in one order of magnitude difference of conductivities.     

Synthesis and Structural Analysis of New Palladium(II) Thiosaccharinates with Triphenylphosphane or Diphosphanes

A series of palladium(II) thiosaccharinates with triphenylphosphane (PPh₃), bis(diphenylphosphanyl)methane (dppm), and bis(diphenylphosphanyl)ethane (dppe) have been prepared and characterized. From mixtures of thiosaccharin, Htsac, and palladium(II) acetylacetonate, Pd(acac)₂, the palladium(II) thiosaccharinate, Pd(tsac)₂ (tsac: thiosaccharinate anion) ( 1 ) was prepared. The reaction of 1 with PPh₃, dppm, and dppe leads to the mononuclear species Pd(tsac)₂(PPh₃)₂ · MeCN ( 2 ), [Pd(tsac)₂(dppm)] ( 3 ), Pd(tsac)₂(dppm)₂ ( 4 ), and [Pd(tsac)₂(dppe)] · MeCN ( 5 ). Compounds 2 , 4 , and 5 have been prepared also by the reaction of Pd(acac)₂ with the corresponding phosphane and Htsac. All the new complexes have been characterized by chemical analysis, UV/Vis, IR, and Raman spectroscopy. Some of them have been also characterized by NMR spectroscopy. The crystalline structures of complexes 3 , and 5 have been studied by X‐ray diffraction techniques. Complex 3 crystallizes in the monoclinic space group P2₁/n with a = 16.3537(2), b = 13.3981(3), c = 35.2277(7) Å, β = 91.284(1)°, and Z = 8 molecules per unit cell, and complex 5 in P2₁/n with a = 10.6445(8), b = 26.412(3), c = 15.781(2) Å, β = 107.996(7)°, and Z = 4. In compounds 3 and 5 , the palladium ions are in a distorted square planar environment. They are closely related, having two sulfur atoms of two thiosaccharinate anions, and two phosphorus atoms of one molecule of dppm or dppe, respectively, bonded to the Pd^II atom. The molecular structure of complex 3 is the first reported for a mononuclear Pd^II‐dppm‐thionate system.     

Characterization of acid sites on the external surface of zeolites

Styrene oligomerization in the presence of Pd(acac)₂+PPh₃+BF₃OEt₂ catalytic system (acac—acetylacetonate) has been studied. Styrene conversion at optimum conditons (T=343 K, B/Pd=7, P/Pd=2) was as high as 75,000 mol of C₃H₃ per mol of Pd in 7 h with a selectivity to dimers, mostly 1,3-diphenylbut-1-ene, up to 93%.     

Synthesis and structure of the heterotrinuclear chromium-palladium clusters (RC5H4CrCl)2-(μ3S)(μ-SCMe3)2Pd(PPh3) with ferromagnetic exchange interactions over the CrSCr system

Reactions of (RC₅H₄)₂Cr₂(SCMe₃)₂S(I, R = H; II, R = Me) with (PPh₃)₂PdCl₂ in benzene at 20°C gives trinuclear complexes (RC₅H₄)₂Cr₂Cl₂(μ₃-S)(μ-SCMe₃)₂Pd(PPh₃)(III, R = H; IV, R = Me). The structure of IV as a monobenzene solvate is established by an X-ray analysis (black-green triclinic crystals space group P$\text{1}$ with a = 11.403(4), b = 14.933(5), c = 14.131(5) Å, α = 99.13(3), β = 112.72(3), γ = 95.65(3)°, V = 2201.6 Å, Z = 2; IV·C₆H₆). The structure was solved by direct methods and refined in an anisotropic approximation to R = 0.046, R_w = 0.058 for 7643 reflections with I ? 2σ(I). In the molecule of IV metal atoms are separated by non-bonding distances (Cr … Cr 4.079(I), Cr … Pd 3.230(I) and 3.380(I) Å) but linked by the bridging tridentate sulphur atom (CrS 2.339(2) and 2.329(2), PdS 2.327(2) Å), and two SCMe₃ groups between Pd and Cr (CrS 2.396(2) and 2.403(2), PdS 2.350(2) and 2.381(2) Å, Cr?Pd 85.14(6) and 89.92(6)°). The Cl atoms are transferred from Pd to Cr atoms (CrCl 2.308(2) Å) and being terminally coordinated are in trans-positions to each other (as well as η-CH₃C₅H₄ rings) with respect to the Cr₂Pd plane. Cr atoms in III and IV exhibit ferromagnetic exchange interactions over the Cr?Cr system (+2J = 28 and 11 cm^?1, respectively).     

Reactivity of ortho‐Substituted Aryl–Palladium Complexes towards Carbodiimides,Isothiocyanates, Nitriles,and Cyanamides

Complexes [Pd(C₆H₃XH‐2‐R′‐5)Y(N^N)] (X=O, NH; Y=Br, I; R′=H, NO₂; N^N=N,N,N′,N′‐tetramethylethylenediamine (tmeda), 2,2′‐bipyridine (bpy), 4,4′‐di‐tert‐butyl‐2,2′‐bipyridine (dtbbpy)) react with RN?C?E (E=NR, S) or RC≡N (R=alkyl, aryl, NR′′₂) and TlOTf (OTf=CF₃SO₃) to give, respectively, 1) products of the insertion of the C?E group into the C? Pd bond, protonation of the N atom, and coordination of X to Pd, [Pd{κ²‐X,E‐(XC₆H₃{EC(NHR)}‐2‐R′‐4)}(N^N)]OTf or [Pd(κ²‐X,N‐{ZC₆H₃(NH?CR)‐2‐R′‐4})(N^N)]OTf, or products of the coordination of carbodiimides and OH addition, [Pd{κ²‐C,N‐(C₆H₄{OC(NR)}NHR‐2)}(bpy)]OTf; or 2) products of the insertion of the C≡N group to Pd and N‐protonation, [Pd(κ²‐X,N‐{XC₆H₃(NH?CR)‐2‐R′‐4})(N^N)]OTf.     

N-methyl-2,2′-bipyridylium ion (bpyMe) complexes: Synthesis and cyclometallation of [Pd(bpyMe)2Cl2]2+

On prolonged heating in water Pd(bpyMe)Cl₃ (bpyMe = N-methyl-2,2′-bipyridylium cation) cyclometallates to give monomeric Pd(bpyMe-H)Cl₂, whereas the immediate products are a mixture of trans-[Pd(bpyMe)₂Cl₂]²⁺ and anionic palladium species. [Pd(bpyMe)₂Cl₂]²⁺ was synthesised directly from Na₂PdCl₄ and on heating gives Pd(bpyMe-H)Cl₂ with the elimination of bpyMe and H⁺.     

Catalytic activity of Pd(II) and Pd(II)/DAB-R systems for the Heck arylation of olefins

Palladium-catalyzed reactions of aryl bromides with various olefins involving Pd(II)/diazabutadiene (DAB-R) systems have been investigated. The scope of a coupling process using Pd(II) sources and an α-diimine as ligand in the presence of Cs₂CO₃ as base was tested using various substrates. The Pd(OAc)₂/DAB-Cy (1, DAB-Cy=1,4-dicyclohexyl-diazabutadiene) system presents the highest activity with respect to electron-neutral and electron-deficient aryl bromides in coupling with electron rich olefins. The synthesis and X-ray characterization of a Pd(II)-diazabutadiene ligand is reported. Extensive optimization experiments showed that another Pd(II) source, Pd(acac)₂ (acac=acetylacetonate), proved to activate aryl bromides at high temperatures, low catalyst loadings when the appropriate concentration of ⁿBu₄NBr additive was employed. The effect of the DAB-Cy ligand is important at very low catalyst loadings and high temperatures. Pd(acac)₂ and Pd(acac)₂/DAB-Cy precatalysts were very effective for the arylation of various olefins with aryl bromides with respect to reaction rate, catalyst loadings, and functional group tolerance.     

Homo- und heterodinukleare α-Pyridonat-verbrückte Platin- und Palladium-komplexe mit Bis(N-methylimidazol-2-yl)keton (BMIK). Kristallstrukturen von [(BMIK)Pt(α-Pyridonat)2Pt(BMIK)](NO3)2 · 4H2O, [(BMIK)Pd(α-Pyridonat)2Pd(BMIK)](NO3)2 · 4H2O und [(BMIK)Pd(α-Pyridonat)2Pt/Pd(BMIK)](NO3)2 · 4H2O

Homo- and Heterodinuclear α-Pyridonate-bridged Platinum and Palladium Complexes with Bis(N-methylimidazol-2-yl)ketone (BMIK). Crystal Structures of [(BMIK)Pt(α-pyridonate)₂Pt(BMIK)](NO₃)₂ · 4H₂O, [(BMIK)Pd(α-pyridonate)₂Pd(BMIK)](NO₃)₂ · 4H₂O, and [(BMIK)Pd(α-pyridonate)₂Pt/Pd(BMIK)](NO₃)₂ · 4H₂O The isotypic dinuclear complexes [(BMIK)Pt(α-pyridonate)₂Pt(BMIK)](NO₃)₂ · 4H₂O ( 1 ) (P1 ; a = 12.197(5) Å, b = 12.505(5) Å, c = 12.866(5) Å, α = 88.17(3)°, β = 73.55(3)°, γ = 69.84(3)°; Z = 2) and [(BMIK)Pd(α-pyridonate)₂Pd(BMIK)](NO₃)₂ · 4H₂O ( 2 ) (a = 12.408(3) Å, b = 12.660(3) Å, c = 12.913(3) Å, α = 89.55(3)°, β = 74.59(2)°, γ = 68.68(2)°) were prepared by reaction of [Pt(BMIK)(H₂O)₂](NO₃)₂ or [Pd(BMIK)(H₂O)₂](NO₃)₂ with α-pyridone in aqueous solutions at 40°C and were isolated as red air-stable crystals (BMIK = bis(N-methylimidazol-2-yl)ketone). For the synthesis of mixed crystals of 2 with the heterometal complex [(BMIK)Pd(α-pyridonate)₂Pt(BMIK)](NO₃)₂ · 4H₂O ( 3 ) (a = 12.430(4) Å, b = 12.648(3) Å, c = 12.907(4) Å, α = 89.64(2)°, β = 74.57(2)°, γ = 68.65(2)°) α-pyridone was reacted with [Pd(BMIK)(H₂O)₂](NO₃)₂ in a molar ratio of 2 : 1 followed by addition of [Pt(BMIK)(H₂O)₂](NO₃)₂. The dinuclear cations consist of two M(BMIK) moieties (M = Pt, Pd) bridged by the N- and O-atoms of α-pyridonate, forcing the heterocyclic ring into head-head-orientation. Within the dinuclear cation, the two metal atoms are between 2.840 Å and 2.860 Å apart. The intermolecular distances are between 4.762 Å and 4.837 Å. The coordination geometry of both metal atoms is square-planar with the metal atoms being diplaced slightly from their respective coordination planes toward each other. ¹H and ¹⁹⁵Pt NMR spectra are reported for the complexes.     

Synthesis and structure of polynuclear carbonylphosphine clusters of palladium

Reductive condensation of Pd(OAc)₂ in dioxane in the presence of CO and PR₃ (R = Et, Buⁿ) with addition of CF₃COOH leads to the formation of decanuclear Pd₁₀(μ₃-CO)₄(μ₂-CO)₈(PBuⁿ₃)₆ (I) and Pd₁₀(CO)₁₄(PBuⁿ₃) (II) at Pd(OAc)₂:PR₃ molar ratios of 1:4–1:10 and 1:1.5–1:2.5, respectively. The use of CH₃COOH instead of CF₃COOH results in tetranuclear clusters Pd₄(CO)₅(PR₃)₄ (III) and Pd₄(μ₂-CO)₆(PBuⁿ₃) (IV). I ? III and III → IV transformations occur in organic media. The structures of I (space group P2₁/n, Z = λMo, 12125 independent reflections, R = 0.047) and IV (Pz:3, Z = λMo, 3254 reflections, R = 0.098) were established by X-Ray diffractions analysis. Cluster I is a 10-vertex Pd₁₀ polyhedron, an octahedron with four unsymmetrically centered non-adjacent faces. The average PdPd distances in the octahedron are 2.825 Å, in the eight short Pd_oct.Pd_cap. bonds with the “equatorial” Pd atoms of the inner octahedron, bridged by the μ₂-CO ligands, are 2.709 Å, and in the four elongated (without bridging CO groups) bonds with the apical Pd atoms of the octahedron are 3.300–3.422 Å. The PBuⁿ₃ ligands are coordinated to the apical Pd atoms and the capping atoms (PdP 2.291–2.324 Å). Cluster IV is tetrahedral, with the CO ligands symmetrically bridged; PdPd 2.778–2.817; PdP 2.232–2.291; PdC 2.06 Å (average).     

Complexes of metal ions with phosphorus or arsenic containing ligands,part XX. Chelates ofo-phenylenebis(diarylarsines) with palladium(II) and platinum(II) halides,pseudohalides and perchlorates

Summary Two ditertiaryarsines,o-phenylenebis(diphenylarsine), (pdpa) ando-phenylenebis(di-p-tolylarsine), (pdta) yield some new complexes of palladium(II) and platinum(II). These are: square planar M(pdta)X₂ · nCH₂Cl₂, [M = Pd, X = Cl, Br or NCS; M = Pt, X = Cl]; [Pt(A-A)₂] X₂ · nCH₂Cl₂, [(A-A) = pdta, X = Cl, NCS or ClO₄; (A-A) = pdpa, X=ClO₄] and [M₂(A-A)₂(NCS)₂] (ClO₄)₂ · nCH₂Cl₂, [M = Pd, (A-A) = pdta; M = Pt, (A-A) = pdpa]; distorted octahedral M(pdta)₂-X₂nCH₂Cl₂, [M = Pd, X = I; M = Pt, X = Br or I] and [Pd(pdta)₂(H₂O)₂](ClO₄)₂, and five coordinate [M(A-A)₂X] ClO₄ · nCH₂Cl₂, [M = Pd, Pt, (A-A) = pdta, X = I; M = Pt, (A-A) = pdpa, X = Br or I]. The [M₂(A-A)₂(NCS)₂] (ClO₄)₂ · nCH₂Cl₂ complexes are novel in the sense that they contain bridging thiocyanate together with ionic perchlorate. The stereochemical assignments have been made on the basis of i.r. and u.v. spectra as well as conductance data.