Synthesis and reactivity of cyclometalated triamidophosphine complexes of niobium and tantalum
The triamidophosphine protioligand 1 reacts with the homoleptic pentakis(dimethylamido) precursors of niobium and tantalum [M(NMe2)5, where M = Nb, Ta] to form cyclometalated complexes of the type [N2PCN-κ5-N,N,P,C,N]M(NMe2) (2-M). Apart from the three amido donors, one benzylic position of the liga...
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| Main Authors: | , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
April 9, 2015
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| In: |
Inorganic chemistry
Year: 2015, Volume: 54, Issue: 8, Pages: 4094-4103 |
| ISSN: | 1520-510X |
| DOI: | 10.1021/acs.inorgchem.5b00333 |
| Online Access: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1021/acs.inorgchem.5b00333
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| Author Notes: | Malte Sietzen, Hubert Wadepohl, and Joachim Ballmann |
| Summary: | The triamidophosphine protioligand 1 reacts with the homoleptic pentakis(dimethylamido) precursors of niobium and tantalum [M(NMe2)5, where M = Nb, Ta] to form cyclometalated complexes of the type [N2PCN-κ5-N,N,P,C,N]M(NMe2) (2-M). Apart from the three amido donors, one benzylic position of the ligand backbone is deprotonated over the course of this reaction, resulting in the formation of a new M-C bond. As a consequence, a metallaziridine substructure is formed, and the triamidophosphine moiety thus serves as a tetraanionic pentadentate ligand. The dimethylamido complexes 2-M can be converted into the corresponding triflates [N2PCN-κ5-N,N,P,C,N]M(OTf) (3-M) and alkyl complexes [N2PCN-κ5-N,N,P,C,N]M(CH2SiMe3) (4-M) by treatment with triethylsilyl triflate (Et3SiO3SCF3) followed by (trimethylsilyl)methyllithium (LiCH2SiMe3). The alkyl complexes exhibit interesting reactivities, including a second cyclometalative backbone activation affording the trimethylphosphine-stabilized complexes [NP(CN)2-κ6-N,P,C,N,C,N]M(PMe3) (5-M). In the case of tantalum, the formation of a dinuclear hydrido complex (6) is observed upon hydrogenation of 4-Ta. In the case of niobium, the metallaziridine substructure in 4-Nb is prone to ring opening via protonation with triphenylsilylamine (Ph3SiNH2), resulting in formation of the corresponding imido complex [PN3-κ4-P,N,N,N]Nb═NSiPh3 (7). |
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| Item Description: | Gesehen am 17.06.2020 |
| Physical Description: | Online Resource |
| ISSN: | 1520-510X |
| DOI: | 10.1021/acs.inorgchem.5b00333 |