Solvent‐Dependent Reactivity and Photochemistry of Dinuclear and Mononuclear Platinum(IV) Azido Triazaolato Complexes. Issue 14 (16th March 2021)

• Record Type: Journal Article
• Authors: Yao, Kezi; Bertran, Arnau; Morgan, Jacques; Greenhalgh, Charlotte; Edkins, Katharina; Bowen, Alice M.; Farrer, Nicola J.
• Is Part Of: European journal of inorganic chemistry. Issue 14(2021)
• Page Start: 1397
• Page End: 1404
• Publication Date: 2021-03-16
• Subjects: Azides -- Photoactivity -- Platinum -- Radicals -- Structure elucidation; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.202100041
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract: Reaction between the platinum(IV) azido complex trans, trans, trans ‐[Pt(py)2 (N3 )2 (OH)2 ] (1 ) and 1, 4‐diphenyl‐2‐butyne‐1, 4‐dione 2 in MeCN produces the intermediate peroxide‐bridged dimeric platinum(IV) azido triazolato species (5 ), which has been characterised by X‐ray crystallography. However, if the reaction between 1 and 2 is conducted in MeOH it results in decomposition. Over time in MeCN, dimer (5 ) converts into mononuclear complexes trans, trans, trans ‐[Pt(py)2 (N3 )(triazole)(OH)2 ] (3 a /3 b ), which are in dynamic exchange. If resuspended in protic solvents (MeOH, H2 O), 3 a /3 b undergo a slow (22 d) irreversible rearrangement to a cyclised platinum(IV) species 4 which contains a formally N, O‐chelated ligand. Conversion of 3 a /3 b to 4 in d 4 ‐MeOH can be accelerated (384x) by irradiation with visible light, although continued irradiation also produces N3 . and OH . radicals, and the [4 ‐N3 ] + species can be readily detected by ESI‐MS. Solvent choice significantly effects both the cycloaddition reaction between 1 and 2, and the stability of the resultant complexes. Abstract : The choice of solvent is crucial to the success of cycloaddition reactions with platinum(IV) azido complexes. Following synthesis in acetonitrile, rearrangement of the triazole can occur in protic solvents. Irradiation with visible light induces azido radical release, without reduction to Pt II species, due to cyclometallation of the complex.