Thermal behaviour of platinum(II) complexes of diethyl and monoethyl 2-quinolylmethylphosphonates

Summary Thermal study of the molecular and ionic platinum(II) complexes of diethyl (2-dqmp) and monoethyl (2-Hmqmp) ester of 2­quinolylmethylphosphonic acid: dihalide adducts trans-PtL₂X₂ (L=2-dqmp, X=Cl, Br; L=2-Hmqmp, X=Cl), methylquinolinium tetrahaloplatinates [LH⁺]₂[PtX₄^2-] (L=2-dqmp, X=Cl, Br; L=2­Hmqmp, X=Cl, Br), methylquinolinium hexahalodiplatinates [LH⁺]₂[Pt₂X₆^2-](L=2-Hmqmp, X=Cl, Br) and chelate complex Pt(2­mqmp)₂·2H₂O, has been carried out using TG-DTA techniques and the infrared spectroscopic study. There are great differences in the thermal behaviour between various types of complexes, especially between the molecular and the ion-pair salt complexes.     

Luminescence of ortho-metallated platinum(II) complexes

The absorption spectra, emission spectra, and emission lifetimes of Pt(Phpy)₂, Pt(Thpy)₂, and Pt(Bhq)₂ complexes (Phpy⁻, Thpy⁻, and Bhq⁻ are the ortho C-deprotonated forms of 2-phenylpyridine, 2-(2-thienyl)-pyridine, and benzo(h)quinoline) have been studied and compared with those of the C-protonated neutral ligands. For all complexes examined the low-energy absorption bands in the near UV and visible region are assigned to metal-to-ligand charge-transfer transitions. The strong and structured luminescence emissions observed in the 500–600 nm region (lifetime in the microsecond range at 77 K) are assigned to metal-to-ligand charge-transfer excited states.     

Preparation and characterization of tris(iso‐propyl)stibine complexes of palladium and platinum

Tris(iso‐propyl)stibine complexes of palladium and platinum of the type [MX₂(SbⁱPr₃)₂] [M, X = Pd, Cl (1a), Pd, Br (1b), Pd, I (1c), Pt, Cl (2)] have been prepared and characterized by elemental analysis, IR and ¹H NMR spectral data. The structure of 1a, established by X‐ray structural analysis, revealed that the palladium atom is in a square planar environment with mutually trans SbⁱPr₃ ligands. Copyright © 2001 John Wiley & Sons, Ltd.     

1,2-polybutadiene complexes with d8 pseudo-square-planar transition-metal salts based on nickel(II), palladium(II), and platinum(II)

The effects of four d⁸ transition-metal complexes from Group 10 on the thermal, mechanical, optical, and spectroscopic properties of atactic 1,2-polybutadiene are compared, in addition to their ability to induce gelation. Olefin coordination and subsequent metal-catalyzed chemical crosslinking occur much more quickly, and to a greater extent, at ambient temperature with PdCl₂(CH₃CN)₂ than with PtCl₂(C₆H₅CN)₂. Alkene side groups in the polymer attack the pseudo-square-planar metal center (i.e., Pd²⁺ or Pt²⁺) from above or below the plane of the coordinatively unsaturated low-molecular-weight organometallic complex and displace neutral acetonitrile or benzonitrile ligands via an associative mechanism. Gelation occurs much more quickly with Pd²⁺ than with Pt²⁺, and the ambient-temperature elastic modulus of solid polybutadiene/palladium complexes increases significantly, without high-temperature annealing, so that a weak rubbery polymer is transformed into a glass via 3 mol % Pd²⁺. Alkene functional groups in the side chain of the polymer do not coordinate to bis(dimethyl)glyoximatonickel(II) at ambient temperature because (1) it is difficult to displace anionic dimethylgloxime ligands that are bidentate; (2) these planar nickel complexes with C_2h symmetry are stacked along the c axis via interlocking methyl groups on adjacent molecules; and (3) there is a lack of π back-bonding between d_xy on Ni(II) and empty π* antibonding orbitals of CC, which typically stabilizes olefin complexes with pseudo-square-planar d⁸ metal centers. Pseudo-octahedral nickel(II) chloride hexahydrate does not form a complex with the polymer, in agreement with some macroscopic properties of these materials. The observed trend in the transition-metal-modified properties of atactic 1,2-polybutadiene in the solid state and in the gel state is Pd(II) > Pt(II) ≫ Ni(II). © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2270–2285, 2004     

Heteronuclear rhodium, palladium, platinum, and gold organoimido complexes from dinuclear organoamido rhodium precursors

Treatment of the organoamido complexes [Rh(2)(mu-4-HNC(6)H(4)Me)(2)(L(2))(2)] (L(2) = 1,5-cyclooctadiene (cod), L = CO) with nBuLi gave solutions of the organoimido species [Li(2)Rh(2)(mu-4-NC(6)H(4)Me)(2)(L(2))(2)]. Further reaction of [Li(2)Rh(2)(mu-4-NC(6)H(4)Me)(2)(cod)(2)] with [Rh(2)(mu-Cl)(2)(cod)(2)] afforded the neutral tetranuclear complex [Rh(4)(mu-4-NC(6)H(4)Me)(2)(cod)(4)] (2), which rationalizes the direct syntheses of 2 from [Rh(2)(mu-Cl)(2)(cod)(2)] and Li(2)NC(6)H(4)Me. Reactions of [Li(2)Rh(2)(mu-4-NC(6)H(4)Me)(2)(CO)(4)] with chloro complexes such as [Rh(2)(mu-Cl)(2)(CO)(4)], [MCl(2)(cod)] (M = Pd, Pt), and [Ru(2)(mu-Cl)(2)Cl(2)(p-cymene)(2)] afforded the homo- and heterotrinuclear complexes PPN[Rh(3)(mu-4-NC(6)H(4)Me)(2)(CO)(6)] (5; PPN=bis(triphenylphosphine)iminium), [(CO)(4)Rh(2)(mu-4-NC(6)H(4)Me)(2)M(cod)] (M = Pd (6), Pt(7)) and [(CO)(4)Rh(2)(mu-4-NC(6)H(4)Me)(2)Ru(p-cymene)] (8), while the reaction with [AuCl(PPh(3))] gave the tetranuclear compound [(CO)(4)Rh(2)(mu--4-NC(6)H(4)Me)(2)[Au(PPh(3))](2)] (9). The structures of complexes 6, 8, and 9 were determined by X-ray diffraction studies. The anion of 5 reacts with [AuCl(PPh(3))] to give the butterfly cluster [[Rh(3)(mu-4-NC(6)H(4)Me)(2)(CO)(6)]Au(PPh(3))] (10), in which the Au atom is bonded to two rhodium atoms. Reaction of the anion of 5 with [Rh(cod)(NCMe)(2)](BF(4)) gave the tetranuclear complex [Rh(4)(mu-4-NC(6)H(4)Me)(2)(CO)(6)(cod)] (11) in which the Rh(cod) fragment is pi-bonded to one of the arene rings, while the reaction of the anion of 5 with [PdCl(2)(cod)] afforded the heterotrinuclear complex 6 through a metal exchange process.     

Selective synthesis of monoorganotin trihalides: the direct reaction of allylic halides with tin(II) halides catalyzed by platinum and palladium complexes

The reaction of 3-haloalkenes (3-chloropropene, 3-bromopropene, 3-chloro-2-methylpropene, 1-chloro-2-butene) with SnX₂ (X=Cl, Br) to form mono-allyltin trihalides, was catalyzed by several platinum and palladium complexes of the type MZ₂L (M=Pt, Pd; Z=Me, Cl; L=2,2′-bipyridine, 1,10-phenanthroline or dppe). The highest yield of allyltin trichloride was obtained for the reaction of 3-chloropropene with SnCl₂ catalyzed by PdMe₂(phen) (83%) while the yield obtained with the other catalysts decreased in the order PdCl₂(phen), PdCl₂(bipy)>PdMe₂(bipy)>PtCl₂(phen)>PtMe₂(bipy)>PtMe₂(phen)>PtCl₂(bipy). Interestingly, PdCl₂(PhCN)₂ and Pd(PPh₃)₄ had no activity at all. The yield of allyltin trichloride was not only dependent on the activity of the catalyst but also on the decomposition rate of the product in the presence of the catalyst. 3-Bromopropene gave 19% of allyltin tribromide when reacted with SnBr₂. The other 3-haloalkenes did react but the resulting monoallylictin trihalides were not stable enough to produce significant yields. Reaction of both, benzyl chloride and chlorobenzene, led to catalyst decomposition. In addition, SnCl₂ catalyzed formation of polybenzyl was observed in the case of benzyl chloride.     

Air-stable platinum and palladium complexes featuring bis[2,4-bis(trifluoromethyl)phenyl]phosphinous acid ligands

Secondary phosphane oxides, R(2)P(O)H, are commonly used as preligands for transition-metal complexes of phosphinous acids, R(2)P-OH (R=alkyl, aryl), which are relevant as efficient catalysts in cross-coupling processes. In contrast to previous work by other groups, we are interested in the ligating properties of an electron-deficient phosphinous acid, (R(f))(2)P-OH, bearing the strongly electron-withdrawing and sterically demanding 2,4-bis(trifluoromethyl)phenyl group towards catalysis-relevant metals, such as palladium and platinum. The preligand bis[2,4-bis(trifluoromethyl)phenyl]phosphane oxide, (R(f))(2)P(O)H, reacts smoothly with solid platinum(II) dichloride yielding the trans-configured phosphinous acid platinum complex trans-[PtCl(2)({2,4-(CF(3))(2)C(6)H(3)}(2)POH)(2)]. The deprotonation of one phosphinous acid ligand with an appropriate base leads to the cis-configured monoanion complex cis-[PtCl(2)({2,4-(CF(3))(2)C(6)H(3)}(2)PO)(2)H](-), featuring the quasi-chelating phosphinous acid phosphinito unit, (R(f))(2)P-O-H···O=P(R(f))(2), which exhibits a strong hydrogen bridge substantiated by an O···O distance of 245.1(4) pm. The second deprotonation step is accompanied by a rearrangement to afford the trans-configured dianion trans-[PtCl(2)({2,4-(CF(3))(2)C(6)H(3)}(2)PO)(2)](2-). The reaction of (R(f))(2)P(O)H with solid palladium(II) dichloride initially yields a mononuclear palladium complex [PdCl(2)({2,4-(CF(3))(2)C(6)H(3)}(2)POH)(2)], which condenses under liberation of HCl to the neutral dinuclear palladium complex [Pd(2)(μ-Cl)(2){({2,4-(CF(3))(2)C(6)H(3)}(2)PO)(2)H}(2)]. The equilibrium between the mononuclear [PdCl(2)({2,4-(CF(3))(2)C(6)H(3)}(2)POH)(2)] and dinuclear [Pd(2)(μ-Cl)(2){({2,4-(CF(3))(2)C(6)H(3)}(2)PO)(2)H}(2)] palladium complexes is reversible and can be shifted in each direction by the addition of base or HCl, respectively. Treatment of palladium(II) hexafluoroacetylacetonate, [Pd(F(6)acac)(2)], with a slight excess of (R(f))(2)P(O)H yields the complex [Pd(F(6)acac)({2,4-(CF(3))(2)C(6)H(3)}(2)PO)(2)H]. The quasi-chelating phosphinous acid phosphinito unit, which is formed by the liberation of HF(6)acac, is characterized by a O···O distance of 244.1(3) pm. These transition metal complexes are stable towards air and moisture and can be stored for months without any evidence of decomposition.     

Palladium(II) and platinum(II) complexes of (1R,2R)‐(−)‐1,2‐diaminocyclohexane (DACH) with various carboxylato ligands and their cytotoxicity evaluation

Several palladium(II) and platinum(II) complexes analogous to oxaliplatin, bearing the enantiomerically pure (1R,2R)‐(?)‐1,2‐diaminocyclohexane (DACH) ligand, of the general formula {MX₂[(1R,2R)‐DACH]}, where M = Pd or Pt, X (COO)₂, CH₂(COO)₂, , , {1,1′‐C₅H₈(CH₂COO)₂}, [1,1′‐C₆H₁₀(CH₂COO)₂], [1,1′‐(COO)₂ferrocene], , , , MeCOO and Me₃CCOO, were synthesized. All the complexes prepared were characterized physicochemically and spectroscopically. Some selected complexes were screened in vitro against several tumor cell lines and the results were compared with reference standard drug, oxaliplatin. Copyright © 2009 John Wiley & Sons, Ltd.     

Synthesis and vibrational study of platinum(II) and palladium(II) complexes of glyoxilic acid oxime

New platinum(II) and palladium(II) complexes of glyoxilic acid oxime (gao) have been prepared and characterised by infrared (4000–150 cm⁻¹) and Raman (4000–200 cm⁻¹) spectra. The gao acts as bidentate ligand bonding through the oxime nitrogen and carboxyl oxygen atoms to form neutral bis-chelate square-planar complexes. The lowest energy conformer of the gao ligand (ectt) was selected among 16 theoretically possible conformers on the basis of ab initio calculations at HF/3-21G*, HF/6-31G* and HF/6-311** levels of the theory from which structural parameters and conformational stabilities have been obtained. A complete vibrational assignment of the gao was performed for the lowest energy ectt conformer on the basis of ab initio optimised parameters and normal coordinate analysis calculations (PED). NCA calculations of the complexes studied were also performed.     

Possible transition from rod-like to disc-like behaviour in ortho-metallated imine complexes of palladium(II): crystal and molecular structure of three palladium complexes

Two series of ortho-metallated palladium imine complexes are reported that contain a coordinated β-diketonate group. In one group the chain length of the imine is varied while the β-diketone is unchanged; in the other the imine chains are both fixed as methoxy and the structure of the β-diketonate is varied. The mesomorphism of these new complexes is reported and discussed in relation to the search for materials showing a biaxial nematic phase.     

Copper(II), palladium(II) and platinum(II) chloride complexes with 5-amino-2-tert-butyltetrazole: Synthesis, characterization and cytotoxicity

Complexes CuL₃Cl₂, PdL₂Cl₂ and PtL₂Cl₂, where L is a novel ligand from the series of 2-substituted 5-aminotetrazoles, namely 5-amino-2-tert-butyltetrazole (1), have been synthesized by the reaction of metal(II) chlorides with 1 and characterized by IR spectroscopy, thermal and X-ray analyses. The crystallographic structural analysis of these complexes revealed that 1 acts as a monodentate ligand coordinated to the metal via endocyclic N4 atom. Platinum complex demonstrates promising cytotoxicity against human cervical carcinoma cells with IC₅₀ value average between those of cisplatin and carboplatin.     

N-aminorhodamne complexes of palladium(II), palladium(IV) and platinum(II)

Summary TheN-aminorhodanine (L) complexes: PdLX, (X = Br or I), ML_1.5Cl₂ (M = Pd or Pt), PtL₂X₂ (X = Br, I or ClO₄), PdL₃(ClO₄)₂, PdL_1.5Cl₄ and PdL₃(ClO₄)₄ have been prepared and investigated. The ligand is bonded to the metal ion through the aminic nitrogen atom as monodentate or through this atom and the thiocarbonylic sulphur atom when it acts as chelating or bridging ligand. The carbonylic oxygen atom is never coordinated.     

Synthesis,characterization, and cytotoxicity of platinum(II)/palladium(II) complexes with 4-toluenesulfonyl-L-amino acid dianion and diimine/diamine

Eight new platinum(II)/palladium(II) complexes with 4-toluenesulfonyl-L-amino acid dianion and diimine/diamine ligands, [Pd(en)(Tsile)]·H₂O (1), [Pd(bipy)(Tsile)] (2), [Pd(bipy)(Tsthr)]·0.5H₂O (3), [Pd(phen)(Tsile)]·0.5H₂O (4), [Pd(phen)(Tsthr)]·H₂O (5), [Pd(bqu)(Tsthr)]·1.5H₂O (6), [Pt(en)(Tsser)] (7), and [Pt(en)(Tsphe)]·H₂O (8), have been synthesized and characterized by elemental analyses, ¹H NMR and mass spectrometry. The crystal structure of 7 has been determined by X-ray diffraction. Cytotoxicities were tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and sulforhodamine B assays. The complexes exert cytotoxicity against HL-60, Bel-7402, BGC-823, and KB cell lines with 4 having the best cytotoxicity against HL-60, Bel-7402, and BGC-823 cell lines; the compounds are less cytotoxic than cisplatin.     

Synthesis and structure of highly substituted pyrazole ligands and their complexes with platinum(II) and palladium(II) metal ions

Reaction of 3-methoxycarbonyl-2-methyl- or 3-dimethoxyphosphoryl-2-methyl-substituted 4-oxo-4H-chromones 1 with N-methylhydrazine resulted in the formation of isomeric, highly substituted pyrazoles 4 (major products) and 5 (minor products). Intramolecular transesterification of 4 and 5 under basic conditions led, respectively, to tricyclic derivatives 7 and 8. The structures of pyrazoles 4a (dimethyl 2-methyl-4-oxo-4H-chromen-3-yl-phosphonate) and 4b (methyl 4-oxo-2-methyl-4H-chromene-3-carboxylate) were confirmed by X-ray crystallography. Pyrazoles 4a and 4b were used as ligands (L) in the formation of ML₂Cl₂ complexes with platinum(II) or palladium(II) metal ions (M). Potassium tetrachloroplatinate(II), used as the metal ion reagent, gave both trans-[Pt(4a)₂Cl₂] and cis-[Pt(4a)₂Cl₂], complexes with ligand 4a, and only cis-[Pt(4b)₂Cl₂] isomer with ligand 4b. Palladium complexes were obtained by the reaction of bis(benzonitrile)dichloropalladium(II) with the test ligands. trans-[Pd(4a)₂Cl₂] and trans-[Pd(4b)₂Cl₂] were the exclusive products of these reactions. The structures of all the complexes were confirmed by IR, ¹H NMR and FAB MS spectral analysis, elemental analysis and Kurnakov tests.     

Hemilability and structural considerations in complexes of platinum(II) comprising bis(diphenylphosphanyl)methane monoxide,monosulfide, and monoselenide

The structure of a platinum(II) complex containing (R)-(dimethylamino)ethylnapthyl and bis(diphenylphosphanyl)methane monosulfide ligands, namely, {(R)-1-[1-(dimethylamino)ethyl]napthyl-κ²N,C²}[(diphenylphosphanylmethyl)diphenylphosphine sulfide-κ²P,S]platinum(II) hexafluoridoantimonate dichloromethane monosolvate, [Pt(C₁₄H₁₆N)(C₂₅H₂₂P₂S)][SbF₆]·CH₂Cl₂, was determined. The structural features are compared with analogous platinum bis(diphenylphosphanyl)methane monoxide [dppm(O)] and bis(diphenylphosphanyl)methane monoselenide [dppm(Se)] complexes in relation to their potential hemilability and stereochemical nonrigidity.     

Some palladium(II) and platinum(II) lead bonded complexes

Complexes of the type M(PPh₃)₂(PbPh₃)₂ [M = Pd, (Ia) and Pt, (Ib)] have been prepared by oxidative addition of hexaphenyldilead to M(PPh₃)₄. The compound Pt(PPh₃)₂(PbPh₃)₂, (Ib), slowly decomposes in dichloromethane to give cis-Pt(PPh₃)₂(PbPh₃)Ph, (II). which can also be obtained by treating (Ib) with the stoichiometric amount of LiPh. Reaction of Pt(PPh₃)₄ with hexamethyldidead gives the complex Pt(PPh₃)₂(PbMe₃)Me directly.The MPb bonds are easily cleaved by bromine, iodine and hydrogen bromide. The X-ray structure of (II) has been determined using three-dimensional counter data and refined by the least-square method (R = 0.07). The crystals are monoclinic a = 22.501, b = 10.502, c = 24.120 Å, β = 113.43°, space group P2₁/c with Z = 4. The complex exhibits a cis configuration, with the coordination around the platinum atom essentially square-planar: the PtPb and PtC(phenyl)bond lengths are 2.698(1) and 2.055(3)Å, respectively.     

Specific interactions of n-donor adsorbates with N-benzoylthiourea-copper(II) complexes chemically bonded to silica supports

Summary Silica was modified with -aminopropyltriethoxylsilane, and then the amino group was converted into an N-benzoylthiourea compound. Treatment with anhydrous CuCl₂ solution, gave a copper(II) complex on the surface. In order to estimate the ability of the complex to interact specifically with electron donors, a number of retention parameters were determined for three groups of compounds showing electron-donor properties: ketones, ethers and nitroalkanes. On the basis of the results, the effect of adsorbate structure on the strength of specific interactions was established. The packings studied may be useful for the analysis of the mixtures of ketones, ethers, and nitroalkanes.     

Syntheses and crystal structures of a series of palladium(II) and platinum(II) complexes bearing new hydrazine-based bisphosphinite ligands equipped with pyridyl arms

This paper reports the synthesis of the hydrazine-based bisphosphinito ligands (RO)₂PN(Me)N(Me)P(OR)₂ (R = 2-hydroxy-6-methyl-pyridyl or 3-hydroxy-6-methyl-pyridyl) and their palladium and platinum complexes whose structures were unequivocally determined by X-ray crystallography.     

Phosphino-aminothiazoline platinum(II) and platinum(II)/gold(I) complexes: structural, chemical and vapoluminescent properties

Phosphino-amino-thiazolines and -thiazoles can exist in solution in two tautomeric forms, in which the N-H proton involves the endo-cyclic or exo-cyclic nitrogen atom. The two tautomers show different reactivities toward alcoholysis; the imino form degrades more rapidly. Their bischelated platinum complexes were studied in the solid state by single crystal X-ray diffraction. Thus, the unique stereoelectronic features of the [Pt(PN(th))] (PN(th)=diphenylposphino-aminothiazoline) moiety were revealed. The complex cis-[Pt(PN(th))(2)] reacts with gold(I) salts to yield dimetallic compounds, the molecular structures of which have been determined by X-ray diffraction. Solid cis-[Pt(PN(th))(2)] shows vapoluminescent properties if exposed to alcohol vapors. A combined photophysical and crystallographic investigation has been carried out to clarify the unprecedented rigidochromic role of the alcohol in this phenomenon.     

电感耦合等离子体原子发射光谱（ICP-AES）法测定高镍铜液体样品中金、钯、铂

为实现中控液体物料中金、钯、铂元素的精准定量分析,为工艺生产定向富集和高效提取提供数据支持,本文建立了ICP—AES法测定中控冶炼系统中高镍铜液体样品中金、铂和钯3种元素含量的测定方法。确定了试液用碲共沉淀,贵金属进入滤渣,经火试金分离富集得到贵金属合粒,合粒经王水溶解后,于王水介质中在电感耦合等离子光谱仪上同时测定金钯铂的量。该方法金、铂、钯的测定范围为 0.014mg/L～5mg/L,回收率为92.2%～104.4%, RSD为3.21%～10.58%,方法满足高镍、铜液体样品中金、钯、铂元素的测定。