Stable Dihydrogen Complexes of Cobalt(−I) Suggest an Inverse <i>trans</i>-Influence of Lewis Acidic Group 13 Metalloligands

Vollmer, Matthew V.; Xie, Jing; Lu, Connie C.

doi:10.1021/jacs.7b02870

Cited by 70 publications

(64 citation statements)

References 57 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The presence of an energetically low-lying metal-based p orbital has also been invoked in Ni 0 and Co –I bimetallic complexes bearing a group 13 metalloligand. 71,72 In this work, the 2a 1 LUMO is important because it is the acceptor orbital for electronic transitions observed by Fe K-edge XAS in the pre-edge region ( vide infra ).…”

Section: Resultsmentioning

confidence: 99%

Enhanced Fe-Centered Redox Flexibility in Fe–Ti Heterobimetallic Complexes

et al. 2019

Self Cite

View full text Add to dashboard Cite

Previously, we reported the synthesis of Ti[N( o -(NCH 2 P( i Pr) 2 )C 6 H 4 ) 3 ] and the Fe–Ti complex, FeTi[N( o -(NCH 2 P( i Pr) 2 )C 6 H 4 ) 3 ], abbreviated as TiL ( 1 ), and FeTiL ( 2 ), respectively. Herein, we describe the synthesis and characterization of the complete redox families of the monometallic Ti and Fe–Ti compounds. Cyclic voltammetry studies on FeTiL reveal both reduction and oxidation processes at −2.16 and −1.36 V (versus Fc/Fc + ), respectively. Two isostructural redox members, [FeTiL] + and [FeTiL] − ( 2 ox and 2 red , respectively) were synthesized and characterized, along with BrFeTiL ( 2-Br ) and the monometallic [TiL] + complex ( 1 ox ). The solid-state structures of the [FeTiL] +/0/– series feature short metal–metal bonds, ranging from 1.94–2.38 Å, which are all shorter than the sum of the Ti and Fe single-bond metallic radii (cf. 2.49 Å). To elucidate the bonding and electronic structures, the complexes were characterized with a host of spectroscopic methods, including NMR, EPR, and 57 Fe Mössbauer, as well as Ti and Fe K-edge X-ray absorption spectroscopy (XAS). These studies, along with hybrid density functional theory (DFT) and time-dependent DFT calculations, suggest that the redox processes in the isostructural [FeTiL] +,0,– series are primarily Fe-based and that the polarized Fe–Ti π-bonds play a role in delocalizing some of the additional electron density from Fe to Ti (net 13%).

show abstract

Section: Resultsmentioning

confidence: 99%

Enhanced Fe-Centered Redox Flexibility in Fe–Ti Heterobimetallic Complexes

et al. 2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…Recently, the double-decker ligand, [N( o -(NCH 2 P i Pr 2 )C 6 H 4 ) 3 ] 3– (abbreviated as L), was used to prepare bimetallic (η 2 -H 2 )M A M B L complexes in which group 13 Lewis acidic supporting metal ions (M B ) induce H 2 binding at Ni(0) and Co(– i ) metal centers (M A ) 15,16. Figueroa and Gabbaï have independently shown that appending a Lewis acidic σ-acceptor to a d 10 transition metal induces binding of a Lewis base donor trans to the σ-acceptor 17–19.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic and kinetic studies of H₂ and N₂ binding to bimetallic nickel-group 13 complexes and neutron structure of a Ni(η²-H₂) adduct

et al. 2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…The dominant contributions to the dative bond originate from the valence d‐shell of the active metal center and corresponding ligand‐centered bonding orbitals . In addition to main group donors, the Lewis acidic ancillary metals in bimetallic cobalt–dinitrogen complexes were also suggested to enhance the reverse‐dative bond flexibility and electronic tuning of the active metal, priming a positive effect on reactivity …”

Section: Introductionmentioning

confidence: 99%

N₂ Reduction on Fe‐Based Complexes with Different Supporting Main‐Group Elements: Critical Roles of Anchor and Peripheral Ligands

Jiang

et al. 2018

Small Methods

View full text Add to dashboard Cite

homogeneous and heterogeneous catalysts for N 2 reduction. [8][9][10][11][12][13][14][15] Artificial catalysts show a great potential because of high activity and tunability, as well as the flexibility to be incorporated into sophisticated electrode assemblies. [16][17][18] Various model catalyst complexes for N 2 reduction were synthesized, which contain low-oxidationstate central metal (such as Mo, Fe, Co, etc.) [19][20][21][22][23] and the supporting ligand that is invariably highly electron donating, such as amides, [10] phosphines, [24][25][26] sulfido, and/or cyclic alkyl(amino)carbenes. [8,27,28] This indicates that the large charge buffer capacity of the central metal is crucial to the catalytic N 2 -to-NH 3 conversion. [14,29,30] To gain further insight into the redoxflexible character of active site in N 2 reduction, studies have been focused on the role of the interaction between central metal and its linked main-group atom in binding, activating, and functionalizing N 2 . [31][32][33] The landmark work on welldefined Fe-based complex with tris(phosphino)alkyl (XP iPr 3 ) (X = C, [28] Si, [34,35] B [20,36] ) ligand featuring axial C/Si/B donor has established a modestly effective catalyst for N 2 -to-NH 3 conversion by addition of protons and electrons at low temperatures. Among the isostructural BP iPr 3 , CP iPr 3 , and SiP iPr 3 series, the system with the most flexible axial linkage, (BP iPr 3 )Fe, gives the greatest catalytic yield under a common set of reaction conditions. [8,20,28,[35][36][37][38][39][40][41][42][43][44] A recent theoretical study elucidated that the reverse-dative Fe→B bonding is of critical importance for the stabilization of different nitrogen intermediates and oxidation states of the Fe center in the catalytic N 2 -to-NH 3 conversion. [45] The dominant contributions to the dative bond originate from the valence d-shell of the active metal center and corresponding ligand-centered bonding orbitals. [46] In addition to main group donors, the Lewis acidic ancillary metals in bimetallic cobaltdinitrogen complexes were also suggested to enhance the reverse-dative bond flexibility and electronic tuning of the active metal, priming a positive effect on reactivity. [47][48][49][50] Considering the importance of reverse-dative bonding between active metal and Lewis-acidic anchor in the catalytic N 2 fixation, a natural question is what happens with the substitution of the apical B atom of Lewis-acidic character with the Lewis-basic N atom in (XP iPr 3 )Fe complex (X denotes the anchor atom). In general, the presence of strong donor groups, such as amides, phosphines, and nitrogen-heterocyclic (NHC) carbenes, Due to the enigmatic existence of the carbon atom in the MoFeS cluster of iron-molybdenum cofactor (FeMoco), the design of biomimetic model catalysts featuring a dative bond between a transition metal and a main group atom is an important topic for efficient reduction of N 2 to NH 3 at ambient conditions. Different anchor atoms (X) for the trigonal bipyramidal (XP iPr 3 )Fe (X =...

show abstract

Stable Dihydrogen Complexes of Cobalt(−I) Suggest an Inverse trans-Influence of Lewis Acidic Group 13 Metalloligands

Cited by 70 publications

References 57 publications

Enhanced Fe-Centered Redox Flexibility in Fe–Ti Heterobimetallic Complexes

Enhanced Fe-Centered Redox Flexibility in Fe–Ti Heterobimetallic Complexes

Thermodynamic and kinetic studies of H₂ and N₂ binding to bimetallic nickel-group 13 complexes and neutron structure of a Ni(η²-H₂) adduct

N₂ Reduction on Fe‐Based Complexes with Different Supporting Main‐Group Elements: Critical Roles of Anchor and Peripheral Ligands

Contact Info

Product

Resources

About

Stable Dihydrogen Complexes of Cobalt(−I) Suggest an Inverse trans-Influence of Lewis Acidic Group 13 Metalloligands

Cited by 70 publications

References 57 publications

Enhanced Fe-Centered Redox Flexibility in Fe–Ti Heterobimetallic Complexes

Enhanced Fe-Centered Redox Flexibility in Fe–Ti Heterobimetallic Complexes

Thermodynamic and kinetic studies of H2 and N2 binding to bimetallic nickel-group 13 complexes and neutron structure of a Ni(η2-H2) adduct

N2 Reduction on Fe‐Based Complexes with Different Supporting Main‐Group Elements: Critical Roles of Anchor and Peripheral Ligands

Contact Info

Product

Resources

About

Thermodynamic and kinetic studies of H₂ and N₂ binding to bimetallic nickel-group 13 complexes and neutron structure of a Ni(η²-H₂) adduct

N₂ Reduction on Fe‐Based Complexes with Different Supporting Main‐Group Elements: Critical Roles of Anchor and Peripheral Ligands