10199-34-5Relevant articles and documents
Binding Properties of Two Novel Phosphane-Modified Tetrapodants and Their Bimetallic Transition Metal Complexes
Dol, Georg C.,Gaemers, Sander,Hietikko, Marko,Kamer, Paul C. J.,Van Leeuwen, Piet W. N. M.,Nolte, Roeland J. M.
, p. 1975 - 1985 (1998)
Two novel phosphane ligands 3 and 4 based on the rigid diphenylglycoluril molecule have been synthesized and characterised. Binding studies with 3 and 4, using 1,3-dihydroxybenzene derivatives reveal that ligands 3 and 4 behave similarly to clip molecule 5, which has the same binding site as ligands 3 and 4. The size of the flexible spacers in the ligands has been varied and the effect of this variation on the association constant of resorcinol denvatives has been determined. These cavity-containing ligands are able to coordinate two transition metal centres, leading to bimetallic macrocycles. The metallamacrocycles formed from 4 containing platinum or rhodium bind the guest, olivetol (5-pentylbenzene-1,3-diol), almost four times as strongly as the free tetrapodant 4. Complexes of 4 having palladium centres display similar or reduced binding affinities for resorcinol derivatives, when compared to free 4. Metal complexes of ligand 3 do not form host-guest complexes, probably because of a too small a ring-size of the metallamacrocycle.
DEPROTONATION REACTIONS BY TRANSITION-METAL PEROXO-COMPLEXES. SYNTHESIS OF AROYLHYDRAZIDO- AND AROYLHYDROXYLAMIDO-COMPLEXES OF PALLADIUM AND PLATINUM AND THE CRYSTAL AND MOLECULAR STRUCTURES OF AND
Bellon, Pier Luigi,Cenini, Sergio,Demartin, Francesco,Manaserro, Mario,Pizzotti, Maddalena,Porta, Francesca
, p. 2060 - 2067 (1980)
By treating (M = Pd or Pt) with C6H5C(O)NHOH, C6H5(NH)NHOH, and p-RC6H4C(O)NHNH2 in ethanol, the complexes , , and (R = H, CH3, or NO2) respectively have been obtained.The reactions of with RNHNH2 (R = H or C6H5) lead only to the zerovalent complex, , while by treating with C6H5NHOH the known complex is obtained.Reactions of the aroylhydrazidoplatinum complexes with molecular oxygen and mineral acids are also reported.The structure of the two title complexes has been determined by X-ray diffraction.The compound is orthorhombic and crystallizes in space group Pna21 with a = 17.365(6), b = 11.218(7), and c = 18.431(8) Angstroem, whereas the disordered is monoclinic and crystallizes in space group P2n1/m with a = 15.829(6), b = 12.269(5), c = 11.833(5) Angstroem, and β = 93.51(3) deg.Both structures have been solved by Patterson and Fourier methods, and refined to R 0.031 and 0.062 for 2057 and 2119 independent reflections, respectively.Both compounds, in the solid state, are essentially square-planar complexes of PtII.The differences between the two structures, which display different packing efficiency, are mainly due to the conformations of the phosphine groups, which are imposed by the chelating ligands.
PLATINUM(II) AND PALLADIUM(II) COMPLEXES OF THIACYCLOOCT-4-ENES; AN UNUSUAL METAL-CATALYZED OLEFIN ISOMERIZATION
Busetto, Luigi
, p. 411 - 418 (1980)
Reactions of MCl42- (M=Pd, Pt) with cis-thiacyclooct-4-ene, cis-2-methyl-thiacyclooct-4-ene and cis-2-phenylthiacyclooct-4-ene (cis-S-4-oct) give chelate complexes of general formula MCl2(cis-S-4-oct).X-ray structure determination indicates that coordination to the metal occurs through both the olefinic double bond and the sulfur atom.Reaction of CN- with the adduct obtained from PtCl42- and a mixture of cis- and trans-2-methylthiacyclooct-4-ene liberates the cis ligand, and GLC analysis excludes the presence of free trans olefin.It is suggested that platinum complexes induce extensive transcis olefin isomerization.
Trans-cis isomerization of [(C6H5)3P]2PtCl2 complex in dimethylformamide solutions
Jacewicz, Dagmara,Pranczk, Joanna,Wyrzykowski, Dariusz,?amoj?, Krzysztof,Chmurzyński, Lech
, p. 620 - 624 (2014)
The kinetics of the trans-cis isomerization reactions of the [(C6H5)3P]2PtCl2 neutral complex catalyzed by four different metal ions: Be2+, Mg2+, Ca2+ and Sr2+ has been studied. The isomerization reactions were investigated in dimethylformamide (DMF) solutions at five temperatures in the range of 278-298 K keeping a constant concentration of metal ions c = 0.5 M. The rates of the isomerization reactions were determined spectrophotometrically by monitoring the absorbance changes at the 277 nm wavelength. The spectral measurements were carried out in the UV-Vis region using the Perkin-Elmer Lambda 650 instrument with the scan accuracy of 1 nm and 1 nm slit width at the 120 scanning rate. The observable rate constants were computed using the Glint program based on the global analysis. The activation energies were determined using the Arrhenius equation. The differences in the structures of the obtained cis and trans geometric isomers were confirmed on the basis of their IR spectra.
From NHC to Imidazolyl Ligand: Synthesis of Platinum and Palladium Complexes d10-[M(NHC)2] (M = Pd, Pt) of the NHC 1,3-Diisopropylimidazolin-2-ylidene
Hering, Florian,Radius, Udo
, p. 3236 - 3245 (2015)
The widely held belief that N-heterocyclic carbenes (NHCs) act only as innocent spectator ligands is not always accurate, even in the context of well-explored reactions. Ligand exchange in the conversion of [Pt(PPh3)2(I2-C2H4)] (3) to [Pt(iPr2Im)2] (2) depends critically on the particular reaction conditions employed, with slight changes leading to vastly different outcomes. In addition to [Pt(iPr2Im)2] (2), complexes [Pt(iPr2Im)(PPh3)(I2-C2H4)] (5) and trans-[Pt(iPr2Im)2(iPr-Im)(H)] (6) were isolated and in the case of 6 fully characterized. Complex 5 represents the first mixed-olefin complex in transition metal chemistry containing both an NHC and a phosphine ligand. Chemical degradation of the NHC was shown to yield the new imidazole-2-yl iPr-Im? in 6. Therefore, the synthesis of [Pt(iPr2Im)2] (2) via metallic reduction of the ionic precursor [Pt(iPr2Im)3(Cl)]+Cl- (9) is favorable, a procedure adaptable to analogous palladium compounds. While [Pd(iPr2Im)3(Cl)]+Cl- (8) is the only product obtained from the reaction of iPr2Im and PdCl2, neutral [Pt(iPr2Im)2(Cl)2] (10), formed as a mixture of its two stereoisomers cis-10 and trans-10, is available through precise control of the stoichiometry in the reaction of PtCl2 and exactly 2 equiv of iPr2Im.
Protonation of cyclopropene complexes of platinum(0) and the reduction of cyclopropene by nitrogenases
Leigh, G. Jeffery,McKenna, Charles E.,Mc Mahon, C. Niamh
, p. 193 - 201 (1998)
The reactions of a series of platinum(0) cyclopropene complexes with HCl have been studied, and it is shown that the products include both ring-intact (cyclopropane-type) and ring-opened (propene-type) materials. All products are believed to be formed by hydrocarbon insertions into transient platinum-hydrogen bonds formed by addition of HCl to platinum. Mechanistic interpretation is complicated by group migrations, and double-bond shifts. Oxidative additon of a σ-cyclopropyl to platinum plays a part in ring-opening reactions, whereas the cyclopropanes are believed to be produced by further hydrocarbon insertions into transient platinum-hydrogen bonds. The relevance of these models to the mechanism of reduction of cyclopropene by nitrogenases is discussed.
Synthesis and reactivity of cis-dichloro(enamine)(amine)platinum(II) complexes
Doran, Sheryl L.,Brown, David B.,Allen, Christopher W.
, p. 111 - 118 (1988)
The reaction of Zeise's dimer, trans-μ-dichlorobis(ethylene)platinum(II) chloride, with a variety of alkyl-substituted enamines led to complexes of the type cis-, where the enamine ligand is coordinated to the platinum(II) center through its nucleophilic carbon atom (C(2)) and the amine ligand is derived from the parent enamine.Analogous palladium complexes were prepared.The complexes were characterized by elemental analysis, NMR (1H, 13C), and IR spectroscopy.Addition of 1 equiv.Ph3P to cis- resulted in substitution of the enamine ligand by Ph3P.When 2 equiv.Ph3P were added, both the enamine and amine ligands were replaced.Hydrolysis of cis- in dilute acetic acid resulted in formation of cis-, through enamine hydrolysis.Possible mechanisms for these reactions and for the formation of the complexes are discussed.
Komplexchemie perhalogenierter Cyclopentadiene und Alkine. IX. Darstellung einiger Phosphoniumacetylid-Komplexe und Struktur von (Ph3P)Cl2Pd(CCPPh3)
Suenkel, Karlheinz
, p. 101 - 108 (1992)
The reaction of dichloroethyne with Pd(PPh3)4 or RhCl(PPh3)3 gives complexes with a phosphoniumacetylide ligand, Ph3P+ CC-.A platinum compound with the same ligand can be prepared by reaction of Pt(PPh3)2(C2H4) with CCl>+ Cl-.The molecular structure of the palladium complex has been determined by X-ray diffraction methods.
5-Aminoorotic acid, a versatile ligand with the ability to exhibit differing co-ordination and hydrogen-bonding modes: Synthesis and crystal structures of platinum(II) complexes
Burrows, Andrew D.,Mingos, D. Michael P.,White, Andrew J. P.,Williams, David J.
, p. 3805 - 3812 (1996)
The complex [Pt(cod)Cl2] (cod = cycloocta-1,5-diene, C8H12) reacted with 2 equivalents of PPh3 and an excess of 5-aminoorotic acid (5-amino-2,6-dioxo-1,2,3,6-tetrahydropyrimidine-4-carboxylic acid, H4L) in the presence of silver(I) oxide to give two isomers of [Pt(PPh3)2(H2L)] 1 and 2. Complexes 1 and 2 can be separated by fractional crystallisation but, in CDCl3 solution, each slowly converts into an equilibrium mixture of the two. Crystal structure determinations have shown that in both 1 and 2 the 5-aminoorotate ligand coordinates to the platinum atom as a dianion. In 1 this is achieved via deprotonation of the carboxylic acid and the loss of an amino NH2 proton, leading to a six-membered chelate ring, whereas in 2 it is by deprotonation of the carboxylic acid and loss of the amido proton, leading to a five-membered chelate ring. This difference in co-ordination mode leads to a difference in the orientation of the hydrogen-bond donors and acceptors remaining on the ligand which, in turn, leads to different supramolecular structures, dimers for 1 and tetramers for 2, with the latter structurally similar to guanine tetrads. These naturally occurring units are stabilised by alkali-metal ions, but reaction of 2 with a compound such as NaBF4 in a two-phase dichloromethane-water system led to [Pt2(PPh3)4(HL)][BF4] as the only platinum-containing product. A crystal structure determination showed that in this complex the ligand is trianionic, deprotonated at the carboxylic acid and both the amido and amino nitrogen atoms, co-ordinating to two platinum atoms via five- and six-membered chelate rings. When dppe [1,2-bis(diphenylphosphino)ethane] was used instead of PPh3 only one isomer of [M(dppe)(H2L)] (M = Pt 3 or Pd 4) was observed for both platinum and palladium, containing the five-membered chelate ring.
OXIDATION VON DICHLORMETHAN ZU EINEM CARBONAT-LIGANDEN
Scherer, O. J.,Jungmann, H.,Huessong, K.
, p. C1 - C4 (1983)
The reaction of CH2Cl2 with (Ph3P)2PtO2 affords cis-(Ph3P)2PtCl2, (Ph3P)2Pt(CO3), Ph3PO and H2O. 31P NMR studies of this oxidation of CH2Cl2 to a carbonato ligand give evidence for the intermediates (Ph3P)2Pt(OOCH2Cl)Cl and .With formic acid (Ph3P)2PtO2 yields the formate complex cis.
