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Abstract We introduce the heterocumulene ligand [(Ad)NCC(tBu)]−(Ad=1‐adamantyl (C10H15),tBu=tert‐butyl, (C4H9)), which can adopt two forms, the azaalleneyl and ynamide. This ligand platform can undergo a reversible chelotropic shift using Brønsted acid‐base chemistry, which promotes an unprecedented spin‐state change of the [VIII] ion. These unique scaffolds are prepared via addition of 1‐adamantyl isonitrile (C≡NAd) across the alkylidyne in complexes [(BDI)V≡CtBu(OTf)] (A) (BDI−=ArNC(CH3)CHC(CH3)NAr), Ar=2,6‐iPr2C6H3) and [(dBDI)V≡CtBu(OEt2)] (B) (dBDI2−=ArNC(CH3)CHC(CH2)NAr). ComplexAreacts with C≡NAd, to generate the high‐spin [VIII] complex with a κ1‐N‐ynamide ligand, [(BDI)V{κ1‐N‐(Ad)NCC(tBu)}(OTf)] (1). Conversely,Breacts with C≡NAd to generate a low‐spin [VIII] diamagnetic complex having a chelated κ2‐C,N‐azaalleneyl ligand, [(dBDI)V{κ2‐N,C‐(Ad)NCC(tBu)}] (2). Theoretical studies have been applied to better understand the mechanism of formation of2and the electronic reconfiguration upon structural rearrangement by the alteration of ligand denticity between1and2.
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Metal‐Ligand Cooperativity to Assemble a Neutral and Terminal Niobium Phosphorus Triple Bond (Nb≡P)
Abstract Decarbonylation along with P‐atom transfer from the phosphaethynolate anion, PCO−, to the NbIVcomplex [(PNP)NbCl2(NtBuAr)] (1) (PNP=N[2‐PiPr2‐4‐methylphenyl]2−; Ar=3,5‐Me2C6H3) results in its coupling with one of the phosphine arms of the pincer ligand to produce a phosphanylidene phosphorane complex [(PNPP)NbCl(NtBuAr)] (2). Reduction of2with CoCp*2cleaves the P−P bond to form the first neutral and terminal phosphido complex of a group 5 transition metal, namely, [(PNP)Nb≡P(NtBuAr)] (3). Theoretical studies have been used to understand both the coupling of the P‐atom and the reductive cleavage of the P−P bond. Reaction of3with a two‐electron oxidant such as ethylene sulfide results in a diamagnetic sulfido complex having a P−P coupled ligand, namely [(PNPP)Nb=S(NtBuAr)] (4).
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- Award ID(s):
- 2154620
- PAR ID:
- 10442954
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 61
- Issue:
- 52
- ISSN:
- 1433-7851
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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