17836-09-8Relevant articles and documents
Cycloneophylplatinum Chemistry: A New Route to Platinum(II) Complexes and the Mechanism and Selectivity of Protonolysis of Platinum-Carbon Bonds
Fard, Mahmood Azizpoor,Behnia, Ava,Puddephatt, Richard J.
, p. 3368 - 3377 (2018/10/02)
A new route to cycloneophylplatinum(II) complexes is reported and the selectivity of protonolysis of the platinum-aryl and -alkyl bonds has been determined. Reaction of [PtCl2(SMe2)2] with neophylmagnesium chloride gives the binuclear cycloneophylplatinum(II) complex [Pt2(CH2CMe2C6H4)2(μ-SMe2)2], 1, which is shown to exist as a mixture of syn and anti isomers. Complex 1 reacts reversibly with SMe2 to give [Pt(CH2CMe2C6H4)(SMe2)2], 2, and irreversibly with bidentate ligands NN = 3,4,7,8-tetramethyl-1,10-phenanthroline (phen?) or 4,4′-di-t-butyl-2,2'bipyridine (bubipy) to give the corresponding complexes [Pt(CH2CMe2C6H4)(phen?)], 3, and [Pt(CH2CMe2C6H4)(bubipy)], 4, respectively. Complex 2 reacts with HCl initially by cleavage of the aryl-platinum bond to give mostly trans-[PtCl(CH2CMe2Ph)(SMe2)2], which then rearranges to an equilibrium mixture with trans-[PtCl(C6H4-2-t-Bu)(SMe2)2], while 3 and 4 react to give [PtCl(CH2CMe2Ph)(phen?)] and [PtCl(CH2CMe2Ph)(bubipy)], which do not undergo the isomerization reaction. The protonolysis reactions occur by way of a platinum(IV) hydride complex in each case, and the unusual reactivity of complex 2 is attributed to the ease of dissociation of the Me2S ligands.
NOVEL IRIDIUM-PLATINUM COMPLEX AND METHOD FOR PRODUCING SAME
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Page/Page column 7, (2009/01/20)
An iridium-platinum complex of the following formula: wherein Cp* is a pentamethylcyclopentadienyl ligand or the like, X is a hydrogen atom, or a substituent group such as a bromine atom or an organic group disposed at a position ortho, meta or para to the phenyl group, or at a combination of the positions, and Y is a methyl group or the like.
Reactivity studies of trans-[PtClMe(SMe2)2] towards anionic and neutral ligand substitution processes
Otto, Stefanus,Roodt, Andreas
, p. 4626 - 4632 (2007/10/03)
Reaction of trans-[PtClMe(SMe2)2] with the mono anionic ligands azide, bromide, cyanide, iodide and thiocyanate result in substitution of the chloro ligand as the first step. In contrast the neutral ligands pyridine, 4-Me-pyridine and thiourea substitute a SMe2 ligand in the first step as confirmed by 1H NMR spectroscopy and the kinetic data. Detailed kinetic studies were performed in methanol as solvent by use of conventional stopped-flow spectrophotometry. All processes follow the usual two-term rate law for square-planar substitutions, kobs = k1 + k2[Y] (where k1 = kMeOH[MeOH]), with k1 = 0.088 ± 0.004 s-1 and k2 = 1.18 ± 0.13, 3.8 ± 0.3, 17.8 ± 1.3, 34.9 ± 1.4, 75.3 ± 1.1 mol-1 dm3 s-1 for Y- = N3, Br, CN, I and SCN respectively at 298 K. The reactions with the neutral ligands proceed without an appreciable intercept with k2 = 5.1 ± 0.3, 15.3 ± 1.8 and 195 ± 3 mol-1 dm3 s-1 for Y = pyridine, 4-Me-pyridine and thiourea, respectively, at 298 K. Activation parameters for MeOH, N3-, Br-, CN-, I-, SCN-, and Tu are ΔH≠ = 47.1 ± 1.6, 49.8 ± 0.6, 39 ± 3, 32 ± 8, 39 ± 5, 34 ± 4 and 31 ± 3 kJ mol-1 and ΔS≠ = -107 ± 5, -77 ± 2, -104 ± 9,-113 ± 28, -85 ± 18, -94 ± 14 and -97 ± 10 J K-1 mol-1, respectively. Recalculation of k1 to second-order units gives the following sequence of nucleophilicity: MeOH 3- - ～ py - - - 2)2] and SCN- follows the same rate law as stated above with k2 = 75.3 ± 1.1, 236 ± 4 and 442 ± 5 mol-1 dm3 s-1 for X- = Cl, I and N3, respectively, at 298 K. The corresponding activation parameters were determined as ΔH≠ = 34 ± 4, 32 ± 2 and 39.3 ± 1.7 kJ mol-1 and ΔS≠ = -94 ± 14, -86 ± 8 and -68 ± 6 J K-1 mol-1. All the kinetic measurements indicate the usual associate mode of activation for square planar substitution reactions as supported by large negative entropies of activation, a significant dependence of the reaction rate on different entering nucleophiles and a linear free energy relationship.
