A Terminal Iridium Oxo Complex with a Triplet Ground State

Delony, Daniel; Kinauer, Markus; Diefenbach, Martin; Demeshko, Serhiy; Würtele, Christian; Holthausen, Max C.; Schneider, Sven

doi:10.1002/ange.201905325

Cited by 9 publications

(3 citation statements)

References 49 publications

(16 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The observation of three paramagnetically broadened and shifted 1 H NMR signals is in agreement with an open shell C 2v symmetric ground state, similar to isoelectronic 3 39,40 . Linear dependence of δ( 1 H) on T −1 indicates population of a single electronic state in the range 193-253 K. Superconducting quantum interference device magnetometry data were obtained after in situ photolysis of solid azide 1 at 10 K (λ exc = 390 nm) leading to a constant rise of the d.c. magnetic moment over time.…”

supporting

confidence: 75%

“…2b) and in line with the absence of an X-band EPR signal for 2 (in both perpendicular and parallel mode). However, the microstate splitting is considerably smaller compared with the isoelectronic complexes [Ir(NtBu) (PNP)] (D = 466 cm −1 ) and (Ir(O)(PNP)) (D = 647 cm −1 ) 39,40 , indicating decreased effective spin-orbit coupling (ζ eff ). As an explanation, ligand-field considerations suggest increased ligand radical character for 2 41 .…”

mentioning

confidence: 99%

See 1 more Smart Citation

A platinum(ii) metallonitrene with a triplet ground state

et al. 2020

Self Cite

View full text Add to dashboard Cite

ational synthetic method development is driven by the ability to relate reactivity to the electronic structures of key transient intermediates. For example, organic nitrenes (R-N) are generally highly reactive monovalent nitrogen species and detailed spectroscopic studies have enabled the assignment of their diverse reaction pathways, such as C-H insertion or N-N coupling, to the accessibility of triplet versus (open shell) singlet spin states 1,2 . In comparison, the well-established class of nitrido complexes (L n MN) commonly features trivalent nitrogen with significant covalent components of M-N σand π-bonding (Fig. 1a) 3 . Increased radical and electrophilic nitrogen character can be formally represented by divalent nitridyl all the way to monovalent metallonitrene contributions 4 . Formal nitrido complexes with predominant subvalent metallonitrene (L n M-N) character, which can be regarded as metal analogues of organic nitrenes, have been proposed as key intermediates in stoichiometric intramolecular [5][6][7][8][9] and intermolecular 10-15 nitrogen atom transfer reactions. However, in contrast to organic nitrenes 16 , authentic metallonitrenes with a monovalent atomic nitrogen ligand remain elusive, which impedes the development of new nitrogen transfer reactions based on electronic structure/reactivity relationships.The emergence of C-H amination and amidation via nitrene transfer as a powerful synthetic tool was fuelled by the development of group 9-11 transition metal catalysts that facilitate selective insertion of coordinated nitrene fragments (Fig. 1b) [17][18][19] . Late transition metals are also instrumental as anode materials in electrocatalytic amine oxidation for synthetic and fuel cell applications [20][21][22] . The dominance of late transition metals in redox transformations of nitrogenous species stimulated fundamental interest in M-N(R) bonding 3 . C-H insertion by L n M-NR species has been associated with electrophilic subvalent nitrene ( 3 NR) 23 or imidyl ( 2 NR − ) [24][25][26] character that arises from low lying d orbitals of late transition met-als. This strongly reduces the imido ( 1 NR 2− ) contribution 27,28 . Similar considerations might apply for metallonitrene (L n M-N) or nitridyl (L n M=N • ) versus nitrido (L n M≡N) species (Fig. 1a). However, intermolecular C-H activation has not been reported for the few known late transition metal nitrido or nitridyl complexes [29][30][31] . The exploitation of nitrogen atom insertion reactivity (Fig. 1b) is still in its infancy; as of yet, catalytic protocols are not known and systematic advances suffer from the lack of well-defined metallonitrene platforms.In this contribution, a formal nitrido complex beyond group 9 is reported. Crystallographic, spectroscopic, magnetic and computational characterization shows a triplet electronic ground state with a predominantly single-bonded metallonitrene (L n Pt ii -N) and nitrogen-centred diradical character. Facile N-atom insertion into C-H, B-H and B-C bonds is demonstrated. In contrast to the...

show abstract

supporting

confidence: 75%

mentioning

confidence: 99%

A platinum(ii) metallonitrene with a triplet ground state

et al. 2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…The magnetic data could be fitted to a zero-field splitting (ZFS) spin-Hamiltonian ( S = 1, g av = 1.74) with large axial ZFS ( D = 407 cm –1 ), which is in line with a triplet ground state that is energetically well separated due to large spin–orbit coupling (SOC). 17 , 45 − 48 DFT computations with the PBE functional confirmed the triplet ground state of complex 3 . However, the corresponding closed-shell solution was found only 1.1 kcal·mol –1 higher in energy suggesting multireference character of the ground-state wave function, which is supported by the magnetic properties yet not sufficiently expressed by DFT computations.…”

Section: Resultsmentioning

confidence: 78%

Cyanate Formation via Photolytic Splitting of Dinitrogen

Schluschaß

Borter

Rupp

et al. 2021

JACS Au

Self Cite

View full text Add to dashboard Cite

Light-driven N 2 cleavage into molecular nitrides is an attractive strategy for synthetic nitrogen fixation. However, suitable platforms are rare. Furthermore, the development of catalytic protocols via this elementary step suffers from poor understanding of N–N photosplitting within dinitrogen complexes, as well as of the thermochemical and kinetic framework for coupled follow-up chemistry. We here present a tungsten pincer platform, which undergoes fully reversible, thermal N 2 splitting and reverse nitride coupling, allowing for experimental derivation of thermodynamic and kinetic parameters of the N–N cleavage step. Selective N–N splitting was also obtained photolytically. DFT computations allocate the productive excitations within the {WNNW} core. Transient absorption spectroscopy shows ultrafast repopulation of the electronic ground state. Comparison with ground-state kinetics and resonance Raman data support a pathway for N–N photosplitting via a nonstatistically vibrationally excited ground state that benefits from vibronically coupled structural distortion of the core. Nitride carbonylation and release are demonstrated within a full synthetic cycle for trimethylsilylcyanate formation directly from N 2 and CO.

show abstract

Synthesis, Structure, and Bonding of d³ Molybdenum–Oxo Complexes

2020

View full text Add to dashboard Cite

Reduction of d2 metal–oxo ions of the form [MO(PP)2Cl]+ (M=Mo, W; PP=chelating diphosphine) produces d3 MO(PP)2Cl complexes, which include the first isolated examples in group 6. The stability and reactivity of the MO(PP)2Cl compounds are found to depend upon the steric bulk of the phosphine ligands: derivatives with bulky phosphines that shield the oxo ligand are stable enough to be isolated, whereas those with phosphines that leave the oxo ligand exposed are more reactive and observed transiently. Magnetic measurements and DFT calculations on MoO(dppe)2Cl indicate the d3 compounds are low spin with a 2[(dxy)2(π*(MoO))1] configuration. X‐ray crystallographic and vibrational‐spectroscopic studies on d2 and d3 [MoO(dppe)2Cl]0/+ establish that the d3 compound possesses a reduced M−O bond order and significantly longer Mo−O bond, accounting for its greater reactivity. These results indicate that the oxo‐centered reactivity of d3 complexes may be controlled through ligand variation.

show abstract

A Terminal Iridium Oxo Complex with a Triplet Ground State

Cited by 9 publications

References 49 publications

A platinum(ii) metallonitrene with a triplet ground state

A platinum(ii) metallonitrene with a triplet ground state

Cyanate Formation via Photolytic Splitting of Dinitrogen

Synthesis, Structure, and Bonding of d³ Molybdenum–Oxo Complexes

Contact Info

Product

Resources

About

A Terminal Iridium Oxo Complex with a Triplet Ground State

Cited by 9 publications

References 49 publications

A platinum(ii) metallonitrene with a triplet ground state

A platinum(ii) metallonitrene with a triplet ground state

Cyanate Formation via Photolytic Splitting of Dinitrogen

Synthesis, Structure, and Bonding of d3 Molybdenum–Oxo Complexes

Contact Info

Product

Resources

About

Synthesis, Structure, and Bonding of d³ Molybdenum–Oxo Complexes