Reaction products, matrix isolation

The reaction of matrix-isolated triazidophenylsilane with r-BuOH led to the formation of /V-(di-f-butoxysilyl)aniline and amino(di-r-butoxy)phe-nylsilane, the trapping products of the nitrile and isonitrile.6... 

The thermal reaction of matrix-isolated lh with acetylene leads to the formation of the intensely red-colored vinylcarbene 18 as the primary product.62 This carbene, which can also be formulated as a 1,3-diradical, has a triplet ground state and is thus formed in a spin-allowed reaction from triplet carbene lh (Scheme... 

There have been numerous studies of low-temperature chemical reactions of matrix-isolated reactants (see, for example, the review by Perutz [1985]). Two of the most interesting from the standpoint of this volume are the reactions of NO with 02 and 03 studied by Smith and Guillory [1977] and Lucas and Pimentel [1979]. The cis dimer (NO)2 has been formed in solid oxygen at 13-29 K. Reaction of this species with the 02 matrix forms the product N204 in an electronically excited state. The transition state structure is reportedly of the form... 

Several reactions of matrix-isolated SiO are known. Irradiation of an argon matrix containing SiO and CI2 leads, via an insertion reaction, to the product OSiCb, the silicon analog of phosgene ... 

The higher homologs of carbon dioxide are synthesized in the photolysis of suitable diazoketones and the reaction products are isolated in an argon matrix. For example, 1,2,3-butatriene-1,4-dione (C4O2) 2 is generated in the photolysis of the five-1 and six-membered... 

An attempt to measure the IR spectrum of the hydroxy carbene [28] after UV photolysis (A>220 nm) of formaldehyde isolated in an argon matrix was unsuccessful (Sodeau and Lee, 1978). Instead of [28] only hydroxyacetal-dehyde resulting from carbene insertion into the C—H bond of the starting formaldehyde was found in the reaction products. Due to its small size, the... 

In order to complete the list of carbon oxides C =0 (n = 1-9) it should be mentioned that, as it was already discussed for C5O, also the higher members C7O, C80, and C9O have not been yet isolated in a matrix, but they could be generated by Endo et al.134,135 in the gas phase by an electric discharge in a mixture of C3O2 and argon. The reaction products were analyzed by rotational spectra, from which the linear cumulenic structure and the bond lengths were derived. 

The matrix photochemistry of 2v proved to be fairly complicated.108 The primary product of the photolysis of 2v is carbene lv, which was identified by ESR spectroscopy. Under the conditions of matrix isolation the carbene showed the expected reactivity towards molecular oxygen (formation of carbonyl oxide 7v) and carbon monoxide (formation of ketene lOv) (Scheme 22). In contrast to the oxocyclohexadienylidenes (la and derivatives) carbene lv slowly reacted with CO2 to give an a-lactone with the characteristic C=0 stretching vibration at 1896 cm-1. The latter reaction indicates that lv is — as expected — more nucleophilic than la. 

Matrix isolation spectroscopy is a powerful technique for identifying unstable products of photodissociation reactions. The small number of boron compounds investigated by this procedure include trioxaborolane, amine-borane and borazine. 

The formation of ethyl radical in the reaction C2H6 + N2O has been confirmed by ESR using the matrix isolation method (3,18). The kinetic results and the product distribution suggest that this reaction route dominates in the oxidation of ethane on V2O5 (5) and alkali metal vanadates (6,8), and very probably in the present case too. 

In early studies, flash vacuum pyrolysis, a method that has proven very valuable in preparative studies of closed-shell compounds,was regarded as the method of choice for the production of radicals for matrix isolation studies. " The disadvantage of this method, which is very well suited for preparative studies of closed-shell compounds, is that the reaction occurs on the walls of a hot tube whose surface may trap radicals (this problem may be alleviated by coating the inside of the tube with gold ). Also, unless a very low vacuum can be maintained in the pyrolysis mbe, collisions between radicals may lead to gas-phase dimerization. 

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