Fast substitution of chloride for bromide and iodide trans to triphenylsilyl in trans-PtCl(SiPh(3))(PMe(2)Ph)(2) has been studied by stopped-flow spectrophotometry in acetonitrile solution. Substitution is reversible with an observable solvent path via the solvento complex trans-[Pt(SiPh(3))(MeCN)(PMe(2)Ph)(2)](+), which has also been synthesized and characterized in solution. Rate constants for the forward and reverse direct substitution pathways are 2900 +/- 100 and 7500 +/- 300 for bromide and 14300 +/- 1100 and 81000 +/- 11000 M(-)(1) s(-)(1) for iodide as nucleophile. The solvento complex reacts ca. 10(3) times faster with iodide than the parent chloride complex, and its reactivity is some 2 orders of magnitude higher than the most reactive solvento species of platinum(II) studied so far. Halide substitution occurs with negative volumes and entropies of activation, but the nucleophilic discrimination is low, and the leaving ligand plays the most important role in the activation process, indicating an I(d) mechanism. Triphenylsilyl has a very high trans effect, comparable to that of ethene and methylisocyanide, due to extensive bond-weakening in the ground state, probably enforced by pi-acception in the transition state. Due to electronic and solvational effects the platinum(II) silyl moiety acts as a hard or borderline metal center in acetonitrile, the thermodynamic stability sequence of its halide complexes being Cl > Br > I, i.e. the reverse of what is usually observed for platinum(II) complexes.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/ic971008l | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
[AsCCAs]-Coordinated Rhenium Hydrides and Their Reactivities Toward Unsaturated Hydrocarbons, Heterocumulenes, and CO.
Inorg Chem
June 2023
Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 276, D-69120 Heidelberg, Germany.
An [AsCCAs] ligand featuring a central alkyne and two flanking arsenic donors was employed for the synthesis of a trihydrido rhenium complex, while the corresponding phosphorus ligand was shown to be less suited. The reactivity of the former trihydride [AsCCAs]ReH () was examined in detail, which revealed that two alternative reaction channels may be entered in dependence of the substrate. Upon reaction of with PhC≡CPh, ethylene, and CS, monohydrides of the general formula [AsCCAs]Re(L)H with L = η-PhC≡CPh (), η-HC═CH (), and η-CS () were formed along with H.
View Article and Find Full Text PDFSimple conversion of trisodium phosphide, NaP, into silyl- and cyanophosphides and the structure of a terminal silver phosphide.
Dalton Trans
March 2022
Department of Chemistry and Applied Biosciences ETH Zurich, Vladimir-Prelog-Weg 1, CH-8049 Zurich, Switzerland.
A reaction of trisodium phosphide (NaP) with chlorosilanes allows for simple derivatization into silyl- and cyano-substituted phosphanide species which were compared with each other. The recently discovered cyano(triphenylsilyl)phosphanide shows unique coordination properties compared to bis(silyl)phosphides.
View Article and Find Full Text PDF1,4-Dihydropyridyl complexes of magnesium: synthesis by pyridine insertion into the magnesium-silicon bond of triphenylsilyls and catalytic pyridine hydrofunctionalization.
Dalton Trans
September 2018
Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52056 Aachen, Germany.
Magnesium bis(triphenylsilyl) [Mg(SiPh3)2(THF)2]·THF (1) reacted with a stoichiometric amount of pyridine to give the magnesium 4-(triphenylsilyl)dihydropyridyl complex [Mg(NC5H5-4-SiPh3)2(THF)3] (2). Using an excess of pyridine, a mixture of magnesium dihydropyridyl [Mg(NC5H6)2(py)4] (3) and 4-(triphenylsilyl)pyridine was formed. Complex 3 underwent exchange with pyridine-d5 at 25 °C to give [Mg(NC5D5H-4)2(py-d5)4] (3-HD).
View Article and Find Full Text PDFActivation of E-Cl bonds (E = C, Si, Ge and Sn) by a C,N-chelated stannylene.
Dalton Trans
June 2013
Department of General and Inorganic Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentská 573, CZ-532 10, Pardubice, Czech Republic.
The reactivity of (L(CN))(2)Sn (1) (where L(CN) is 2-(N,N-dimethylaminomethyl)phenyl-) towards various substrates containing E–Cl bond(s) has been studied (E = C, Si, Ge and Sn). Alkyl chlorides like chloroform or dichloromethane reacts with 1 to form (L(CN))(2)SnCl(2) and unidentified by-products in poor yields. The reaction of benzoyl chloride with 1 at low temperature yielded a thermally unstable product (L(CN))(2)Sn(Cl)C(O)Ph (2) which was isolated and characterized by both multinuclear NMR spectroscopy and X-ray diffraction techniques.
View Article and Find Full Text PDFUnsuccessful attempts to add alcohols to transient 2-amino-2-siloxy-silenes - leading to a new benign route for base-free alcohol protection.
Dalton Trans
October 2010
Department of Biochemistry and Organic Chemistry, Uppsala University, Box 576, 751 23, Uppsala, Sweden.
Thermolytic formation of transient 1,1-bis(trimethylsilyl)-2-dimethylamino-2-trimethylsiloxysilene (2) from N,N-dimethyl(tris(trimethylsilyl)silyl)methaneamide (1) in presence of a series of alcohols was investigated. The products are, however, not the expected alcohol-silene addition adducts but silylethers formed in nearly quantitative yields. Thermolysis of 1 in the presence of both alcohols (MeOH or iPrOH) and 1,3-dienes (1,3-butadiene or 2,3-dimethyl-1,3-butadiene) gives alkyl-tris(trimethylsilyl)silylethers and the [4+2] cycloadducts between the silene and diene, which confirms the presence of 2 and that it is unreactive towards alcohols.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!