Oxidative additions and reductive eliminations number among the most important reactions of transition metal complexes and are of special utility in the chemistry of organomet a l k compounds. Reductive cis-eliminations have also been observed as light-induced processes[']. Thus, irradiation of [IrCIH2(PPh3)3] leads to cis-elimination of H2 and formation of [IrCI(PPh3),] in a single step; the elimination of H2 is concerted, no hydrogen atoms are formed in the photoprocess[ ' bl. Photochemical reductive trans-eliminations have so far not been reported. We have now been able to demonstrate such a reaction with [Pt'V(CN)4(N3)2]2-, which on irradiation is quantitatively converted into [Pt"(CN)4]2-.Of particular interest to us was whether this two-electron reduction of Pt" proceeded via a Pt"' intermediate, since it is generally assumed that both thermal[2a1 as well as photochemical[2b1 conversions of Pt" into Pt" complexes involve two successive one-electron reductions. Should a Pt"' intermediate not be formed, then there are two mechanistic possibilities: While the cleavage of the two ligands in cis-elimination obviously does not involve formation of ligand radicals in the initial reaction step[Ib1 this could be possible on steric grounds in the case of trans-eliminations.We conclude from our investigations that two N3 radicals are formed in the initial step of photochemical reductive transelimination from t r~n s -[ P t ( C N )~( N~)~]~ -by simultaneous two-electron reduction without formation of a Pt"' intermediate: [Pt'V(CN)4(N,)z]2---* [Pt"(CN)4]*-+ 2N; Reaction of K2[Pt(CN)4Br2][31 with a large excess of KN3 in water (reaction time 2d) afforded the compound K2[Pt(CN)4(N3)2], which was isolated in analytically pure form after recrystallization from acetone. The trans structure (D4,,) of the anion follows from the appearance of an IR bandC3] (21 81 cm-') in the region of the CN stretching vibrations. The electron absorption spectrum shows only one intense maximum (j. = 302 nm, E = 18 300) in the longwave region which is assigned to a (N3+ Pt)CT transition.Irradiation of the CT band of the salt dissolved in water led to rapid evolution of nitrogen according to
Das neue Reagens ( 2 ) ergibt rnit Elektrophilen die in Tabelle 1 zusammengestellten Produkte (3) und ( 4 a ) . Die mit Carbonylverbindungen erhaltenen Diole (3 d)-(3 g) cyclisieren rnit Salz~aure/Ether[~~ zu den Dihydroisobenzofuranen ( 4 b)-(4e) (Tabelle 1, unten).
The first light‐induced reductive trans elimination has been observed with the trans‐configurated PtIV complex (1). The primary photochemical step leads, via simultaneous two‐electron reduction avoiding a PtIII intermediate, to two N3 radicals which afford N2 and N atoms at low temperature.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2025 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.