Kinetics and mechanism of molecular A-frame formation in reactions of (Pt/sub 2/(PPh/sub 3/)/sub 2/(. mu. -dppm)/sub 2/)(PF/sub 6/)/sub 2/ with diazomethane, carbon monoxide, sulfur dioxide, sulfur, and hydrogen chloride

Journal Article · Wed Dec 26 00:00:00 EST 1984 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00338a017· OSTI ID:5863855

Muralidharan, S; Espenson, J H

The mechanism of the formation of A frames of the type (Pt/sub 2/(PPh/sub 3/ triphenylphosphine)/sub 2/(..mu..-Y)(..mu..-dppm)/sub 2/)(PF/sub 6/)/sub 2/ (y = CH/sub 2/, CO, S, SO/sub 2/) from (Pt/sub 2/(PPh/sub 3/)/sub 2/(..mu..-dppm)/sub 2/)(PF/sub 6/)/sub 2/ by reaction with CH/sub 2/N/sub 2/, CO, S, and SO/sub 2/ (R) in CH/sub 2/Cl/sub 2/ and other organic solvents has been investigated by using kinetic studies and product analysis. Pseudo-first-order kinetic data (excess (R)/sub 0/) are consistent with either preequilibrium association of R with the complex prior to rate-limiting product formation or unimolecular formation of a common intermediate which is then attacked by R to form the A-frame product. Kinetic studies with (R)/sub 0/ less than or equal to (complex)/sub 0/ substantiate the latter. The most likely intermediate leading to the products is one with a dangling dppm ligand formed by Pt-P bond heterolysis. When (R)/sub 0/ is very large, formation of this intermediate becomes rate limiting and is independent of the nature of R, with k = 2.73 +/- 0.05 x 10/sup -2/ s/sup -1/ (at 25/sup 0/C; ..delta..H = 25.0 kcal mol/sup -1/ and ..delta..S = 18.5 cal mol/sup -1/ K/sup -1/). The same process and mechanism is observed for R = HCl, although with minor numerical differences; similar salt and solvent polarity effects occur in all of the reactions (dppm-bis(diphenylphosphino)methane). 23 references, 1 figure, 3 tables.

• Research Organization: Iowa State Univ., Ames
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 5863855
• Journal Information: J. Am. Chem. Soc.; (United States), Vol. 106:26
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
54 ENVIRONMENTAL SCIENCES
CARBON MONOXIDE
CHEMICAL REACTION KINETICS
DIAZO COMPOUNDS
HYDROCHLORIC ACID
PLATINUM COMPLEXES
SULFUR DIOXIDE
ABSORPTION SPECTROSCOPY
ACETONE
ALKANES
AROMATICS
CHLOROFORM
COMPARATIVE EVALUATIONS
CORRELATIONS
DATA ANALYSIS
EXPERIMENTAL DATA
MATHEMATICAL MODELS
MEDIUM TEMPERATURE
METHANOL
METHYLENE CHLORIDE
MONITORING
PHOSPHINES
PHOSPHORUS FLUORIDES
QUANTITY RATIO
REAGENTS
STRUCTURAL CHEMICAL ANALYSIS
TEMPERATURE DEPENDENCE
ULTRAVIOLET SPECTRA
ALCOHOLS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHLORINATED ALIPHATIC HYDROCARBONS
COMPLEXES
DATA
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
HALOGENATED ALIPHATIC HYDROCARBONS
HYDROCARBONS
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
INFORMATION
INORGANIC ACIDS
KETONES
KINETICS
NUMERICAL DATA
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOSPHORUS COMPOUNDS
REACTION KINETICS
SPECTRA
SPECTROSCOPY
SULFUR COMPOUNDS
SULFUR OXIDES
TRANSITION ELEMENT COMPLEXES
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