Year: 2025
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide The bis-acetate complexes (SbQ 3 )Pt(OAc) 2 ( 1 ) and (SbQ 2 Ph)Pt(OAc) 2 ( 2 ) (Q = 8-quinolinyl) were used to study C–Cl acetoxylation of 1,2-dichloroethane (DCE) to generate 2-chloroethyl acetate and the complexes (SbQ 3 )PtCl 2 ( 1b ) and (SbQ 2 Ph)PtCl 2 ( 2b ), respectively. The first acetoxylation step produced the intermediates (SbQ 3 )Pt(Cl)(OAc) ( 1a ) and (SbQ 2 Ph)Pt(Cl)(OAc) ( 2a ). The reaction was studied using pseudo first order kinetics (excess DCE) in order to compare the rates of reaction of 1 and 2, which revealed that k obs = 2.44(6) × 10 –4 s –1 for 1 and 0.51(2) × 10 –4 s –1 for 2 . The intermediate 1a was synthesized independently, and the solid-state structure was determined using single crystal X-ray diffraction. A non-Sb containing control complex, ( t bpy)Pt(OAc) 2 ( 3 ) ( t bpy = 4,4′-di- tert -butyl-2,2′bipyridine), was studied for the acetoxylation of DCE to form ( t bpy)Pt(Cl)(OAc) with k obs = 0.46(1) × 10 –4 s –1 . Density Functional Theory (DFT) calculations were used to examine possible Pt-mediated mechanisms for the reactions of 1, 2, or 3 with DCE. The lowest energy calculated substitution mechanism occurs with nucleophilic attack by the Pt center on the C−Cl bond followed acetate reaction with the Pt−C bond. However, close in energy and potentially also a viable mechanism is a direct substitution mechanism where the coordinated acetate anion directly reacts with the C−Cl bond of DCE. In addition, the rate of acetoxylation for complex 1 in heated dichloromethane- d 2 and chloroform- d was determined (0.43(1) × 10 –4 s –1 for dichloromethane- d 2 and 0.37(1) × 10 –4 s –1 for chloroform- d ) and compared to the rate of acetoxylation of DCE.
Source: Organometallics
Institutions: University of Virginia, Brigham Young University
Language: English
Subfield: Organic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
OpenAlex ID: W4407782175