Matrix Isolation and Theoretical Study of the Reaction of Substituted Phosphines with CrCl₂O₂

Abstract

The reactions between CrO2Cl2 and a series of substituted phosphines have been investigated using matrix isolation infrared spectroscopy. For all of the phosphines except PF3, twin jet co-deposition of the two reagents into argon matrices at 14 K initially led to the formation of weak bands due to the corresponding phosphine oxide. For all of the phosphines, subsequent irradiation with light of lambda > 300 nm led to the growth of a number of intense new bands that have been assigned to the phosphine oxide complexed to CrCl2O, following an oxygen atom transfer reaction. Gas-phase, merged jet reactions prior to matrix deposition led to a significant yield of the uncomplexed phosphine oxide. Theoretical calculations at the B3LYP/6-311++g(d,2p) level were carried out in support of the experimental work, to support product band assignments and clarify the nature of the molecular complexes.

Theoretical Study on Mechanism for the Reaction of 2-propargyl radical (C3H3) with ammonia (NH3)

“…[2][3][4][5][6][7] There havebeen investigations, both theoretically and experimentally, about the reaction of propargyl radical with other species in the interstellar medium and in combustion systems, including the self-reaction with another propargyl radical, with elements such as H, O( 3 P), C( 3 P), or with other hydrocarbon radicals such as CH3. [8][9][10][11][12][13] The mechanisms of reactions between propargyl radical with O2, H2O, NO, CO, HCNO, OH, H, CH3, and C3H3 were investigated by our group using density functional theory. 5 Reactions of propargyl radical with atoms or with other free radicals usually occur rapidly without energy barriers.…”

“…[2][3][4] In contrast, reactions of propargyl with neutral molecules usually have energy barriers. 10,11,19 There are two reasons why we choose the propargyl radical to study. Firstly, the reactions of propargyl with the oxides of nitrogen NOx, which are important in processes such as thermal DeNOx (Process for reducing NOx emission), NOx-OUT (Process for reducing NO from fossil-fueled and wastefueled stationary combustion sources), RAPRENOx (Rapid reduction of nitrogen oxides) and NO-reburning, are foreshadowed to be barrier-free leading to primary nitroso and nitro derivatives that further undergo a variety of transformations.…”

“…Firstly, the reactions of propargyl with the oxides of nitrogen NOx, which are important in processes such as thermal DeNOx (Process for reducing NOx emission), NOx-OUT (Process for reducing NO from fossil-fueled and wastefueled stationary combustion sources), RAPRENOx (Rapid reduction of nitrogen oxides) and NO-reburning, are foreshadowed to be barrier-free leading to primary nitroso and nitro derivatives that further undergo a variety of transformations. [8][9][10][11][12] Secondly, the main reaction pathways of propargyl radical with either the hydrogen compounds or the hydrocarbons involves a hydrogen abstraction yielding C3H4 whose energy barrier is consistently low. [13][14][19][20][21][22][23][24][25] As far as we are aware, little is actually known about the reactions of C3H3 with other simple molecules such as ammonia and hydrogen halides.…”

Characterisation of photochemically formed reactive species from kinetic and thermodynamic data using UV-Vis. Laser flash photolysis, Time resolved IR and matrix isolation techniques

“…15 Chromylchloride is a very potent oxidising agent and the main focus of this work was to investigate the formation of the appropriate phosphine oxide from the phosphine. When twin jet co-deposition was used the phosphine and CrCl 2 O 2 can only react within the matrix at 14 K. In these experiments photolysis of the resulting matrix (l 4 300 nm) was required to produced a complex of the phosphine oxide and CrCl 2 O (phosphine = PCl 3 , PBr 3 , CH 3 PCl 2 , or (CH 3 ) 2 PCl).…”