| Autor: |
Biswas, Mitrali, Dey, Sanchaita, Dhara, Suman, Panda, Sanjib, Lahiri, Goutam Kumar |
| Předmět: |
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| Zdroj: |
Dalton Transactions: An International Journal of Inorganic Chemistry; 2/7/2024, Vol. 56 Issue 5, p2167-2180, 14p |
| Abstrakt: |
This article addresses the impact of metal–ligand redox cooperativity on the functionalisation of coordinated ligands. It demonstrates the structure–reactivity correlation of bis(aldimine) derived bis-bidentate L (Py-CH＝N–(CH2)n–N＝CH-Py, with n = 2 (L1), 3 (L2), 4 (L3)) as a function of the conformation (syn/anti) of its alkylene linker as well as the overall structural form (cis/trans) of (acac)2RuII(μ-L)RuII(acac)2 complex moieties (1–5) possessing an electron-rich acetylacetonate (acac) co-ligand. A systematic variation of the bridging alkylene unit of L in RuII/RuII-derived 1–5 led to the following reactivity/redox events, which were validated through structural, spectroscopic, electrochemical and theoretical evaluations: (i) Cyclisation of the ethylene linked (syn conformation) bis-aldimine unit of L1 via C–C coupling yielded pyrazine bridged (acac)2RuII(μ-L1′)RuII(acac)2, 1a, while the corresponding anti-form (ethylene linker) of the metal-bound L1 in 2 ((acac)2RuII(μ-L1)RuII(acac)2) led to oxygenation at the ligand backbone (bis-aldimine (L) → bis(carboxamido) (L′′)) via O2 activation to generate RuIIIRuIII-derived (acac)2RuIII(μ-L1′′2−)RuIII(acac)2 (2a). (ii) Consequently, propylene and butylene linked L2 and L3 bridged between two {Ru(acac)2} units in 3 and 4/5 underwent oxygenation of L to L′′ to yield diruthenium(III) complexes 3a and 4a/5a, respectively. (iii) In contrast, analogous L bridged oxidised [(acac)2RuIII(μ-L)RuIII(acac)2](ClO4)2 ([2](ClO4)2–[5](ClO4)2) and [{(PPh3)2(CO)(H)RuII}2(μ-L)](ClO4)2 ([6](ClO4)2–[8](ClO4)2) involving electron poor co-ligands failed to undergo the oxygenation of L irrespective of its n value, reemphasising the effective role of redox interplay between RuII and L particularly in the presence of an electron-rich acac co-ligand in the functionalisation of the latter in 1a–5a. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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