Stabilisation of carbonyl free amidinato-manganese(II) hydride complexes: "masked" sources of manganese(i) in organometallic synthesis

Lea Fohlmeister, Cameron Jones

Research output: Contribution to journalArticleResearchpeer-review

6 Citations (Scopus)

Abstract

Reaction of the amidinato-manganese(ii) bromide complex, [{(κ2-N,N′-Piso)Mn(μ-Br)}3(THF)2] (Piso = [(DipN)2CBut]-, Dip = 2,6-diisopropylphenyl), with K[BHEt3] affords the first example of a structurally authenticated amidinato-manganese(ii) hydride complex, [{(N-,η3-arene-Piso)Mn(μ-H)2}2], via a process which involves a change in the amidinate coordination mode. Treatment of the bulkier precursor complex, [{(Piso′′)Mn(μ-Br)}n] (Piso′′ = [(Dip′′N)2CBut]-, Dip′′ = C6H2Pri 2(CPh3)-2,6,4), with K[BHEt3] did not lead to an isolable manganese hydride complex, but its reaction with the magnesium(i) complex, [{(MesNacnac)Mg}2] (MesNacnac = [(MesNCMe)2CH]-, Mes = mesityl), did. This reaction presumably proceeds via a reactive manganese(i) intermediate, which abstracts hydrogen from a reaction component to give [{(κ2-N,N′-Piso′′)Mn(μ-H)}3]. A comparison of the reactivities of [{(N-,η3-arene-Piso)Mn(μ-H)2}2] and the isomorphous manganese(i) complex, [{(N-,η3-arene-Piso)Mn}2], toward CO, O2 and N2O was carried out. Reactions with the manganese(i) and manganese(ii) species gave identical results, namely the formation of the manganese(i) carbonyl complex, [(κ2-N,N′-Piso)Mn(CO)4] (reactions with CO), and the manganese(iii)-μ-oxo complex, [{(κ2-N,N′-Piso)Mn(μ-O)}2] (reactions with O2 and N2O). These results indicate that [{(N-,η3-arene-Piso)Mn(μ-H)2}2] can act as a "masked" source of an amidinato-manganese(i) fragment in synthetic transformations.

Original languageEnglish
Pages (from-to)1436-1442
Number of pages7
JournalDalton Transactions
Volume45
Issue number4
DOIs
Publication statusPublished - 2016

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