Preparation, unusual spectral properties, and structural characterization of (terpyridine)(tetrahydroborato-H,H')cobalt

Corey, E. J.; Cooper, N. John; Canning, W.M.; Lipscomb, W.N.; Koetzle, T. F.

doi:10.1021/ic00131a036

Cited by 42 publications

(21 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, Co(THF) 2 ·TPY-MOL has shorter Co–N bond distances than those for Co II Cl 2 ·TPY-MOL (Co–N c = 1.90 ± 0.01 Å, Co–N t = 2.09 ± 0.01 Å), but similar Co–N bond distances to a reported low-spin Co II (tpy)(BH 4 ) complex with the (tpy˙) – ligand (Co–N c = 1.810 Å, Co–N t = 1.925 Å). 58 The Co–N bond distance analysis thus supports the formulation of the Co II -(tpy˙˙) 2– electronic structure for Co(THF) 2 ·TPY-MOL.…”

Section: Resultssupporting

confidence: 57%

Metal–organic layers stabilize earth-abundant metal–terpyridine diradical complexes for catalytic C–H activation

et al. 2018

View full text Add to dashboard Cite

show abstract

Section: Resultssupporting

confidence: 57%

Metal–organic layers stabilize earth-abundant metal–terpyridine diradical complexes for catalytic C–H activation

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Complex 4 has a distorted tetragonal‐pyramidal cobalt center coordinated to one intact bidentate silyl–NHC ligand and one newly formed chelating borane–NHC ligand (Figure 2). The η 2 ‐bound benzylborane anion in 4 has a Co–B separation of 2.169(4) Å comparable to that observed for its congeners trans ‐[(Cy 3 P) 2 CoH(η 2 ‐BH 4 )] (2.14(1) Å; Cy= cyclohexyl)21 and [(terpyridine)Co(η 2 ‐BH 4 )] (2.16(1) Å) 22. Replacement of the [IMes′] − anion with the borane–NHC anion in the coordination sphere of the metal led to shorter Co–C(carbene) and Co–Si bonds (1.928(3) and 2.274(1) Å, respectively) in the [(IMesSi)Co] fragment as compared to those of 2 a (2.048(5) and 2.300(2), respectively).…”

Section: Methodssupporting

confidence: 52%

Anchoring of Silyl Donors on a N‐Heterocyclic Carbene through the Cobalt‐Mediated Silylation of Benzylic CH Bonds

Liu

Deng

2013

Angewandte Chemie

View full text Add to dashboard Cite

Neuer Schwung für den Katalysator: Eine Reaktionssequenz aus Cobalt‐vermittelter C‐H‐Aktivierung und Silylierung wurde entwickelt und für die Herstellung von neuartigen Silyldonor‐funktionalisierten NHC‐Komplexen verwendet (siehe Schema; Mes=Mesityl; R=H, Me, Ph). Die erhaltenen Cobalt‐Komplexe zeigen hohe Aktivität und Selektivität in der katalytischen Hydrosilylierung von Olefinen.

show abstract

“…The h 2 -bound benzylborane anion in 4 has a Co-B separation of 2.169(4) comparable to that observed for its congeners trans-[(Cy 3 P) 2 CoH(h 2 -BH 4 )] (2.14(1) ; Cy = cyclohexyl) [21] and [(terpyridine)Co(h 2 -BH 4 )] (2.16 (1) ). [22] Replacement of the [IMes'] À anion with the borane-NHC anion in the coordination sphere of the metal led to shorter Co-C(carbene) and Co-Si bonds (1.928(3) and 2.274(1) , respectively) in the [(IMesSi)Co] fragment as compared to those of 2 a (2.048(5) and 2.300(2), respectively). The shortening of these bond distances could be ascribed to the weak electron-donating ability of the borate anion, which makes the cobalt center less electron-rich and thus strengthens the Co-C and Co-Si interaction.…”

Section: Zhenbo Mo Yang Liu and Liang Deng*mentioning

confidence: 99%

Anchoring of Silyl Donors on a N‐Heterocyclic Carbene through the Cobalt‐Mediated Silylation of Benzylic CH Bonds

2013

View full text Add to dashboard Cite

Silyl ligands stand out as particularly versatile ligands owing to their exceptionally strong s-donating ability and trans effect. [1] These properties should make silyl-containing ligands capable of generating coordinatively unsaturated metal species, directing the coordination and dissociation of other ligands, and therefore conferring enhanced reactivity or accelerated catalytic turnover to their complexes. [2] N-Heterocyclic carbenes (NHCs) are another type of strongly s-donating ligand with a strong trans effect and have joined the cyclopentadienyl anions and phosphine ligands as particularly useful widely applied ligands. [3] Accompanying the emergence of versatile monodentate NHCs, [4] numerous functionalized NHC ligands featuring tethered substitutents or binding sites, such as borate, alkoxide, enolate, amine, amide, imine, heterocycle, thioether, and phosphine groups, have been developed and applied in transition-metal chemistry. [5,6] In contrast, functionalized NHC ligands featuring silyl donors have remained elusive, although some NHCs with silyl substitutents on the imidazole ring are known (Scheme 1). [7] The absence of this type of potentially useful ligand might result from the inherent challenge of combining a nucleophilic carbene with a Lewis acidic silane moiety in the same ligand scaffold, as there have been reports of silanes reacting with NHCs to afford Lewis acid-base adducts, [8] Si À H insertion products, [9] or even ring expansion of the NHC (Scheme 1). [10] With this knowledge in mind, we envisioned that instead of the direct synthesis of a silyl-donor-functionalized NHC ligand, a postsilylation method involving the reaction of hydrosilanes with a cyclometalated transition-metal-NHC complex might be a more feasible route. This idea was inspired by our previous finding that the cyclometalated NHC complex [Co(IMes') 2 ] (1) can react with CO, isocyanides, and diazo compounds to furnish novel donor-group-functionalized NHC complexes. [11] Herein, we report the preparation of the first silyl-donor-functionalized NHC complexes by a sequential cobalt-mediated C À H activation and silylation protocal, their reactivity toward H 2 and BH 3 ·thf, and more interestingly, their remarkable catalytic performance in the catalytic hydrosilylation of 1-octene with PhSiH 3 . In this transformation, the very fast initial rate and the high turnover number and selectivity of these catalysts were superior to those observed for [Co 2 (CO) 8 ] and [(IPr 2 Me 2 ) 2 CoPh 2 ] (IPr 2 Me 2 : 2,5-diisopropyl-3,4-dimethylimidazol-1-ylidene).Our previous study showed that the reduction of [(IMes) 2 CoCl], prepared from [(Ph 3 P) 3 CoCl] and IMes (IMes: 1,3-dimesitylimidazol-2-ylide), with sodium amalgam results in the formation of the cyclometalated cobalt(II)-NHC complex [Co(IMes') 2 ] (1; Scheme 2). [11] Upon further investigation, we found that 1 can be prepared more conveniently by the one-pot reaction of CoCl 2 with IMes (2 equiv) and sodium amalgam (2 equiv; Scheme 2). The addition of PhSiH 3 (1 equiv) to a su...

show abstract

Preparation, unusual spectral properties, and structural characterization of (terpyridine)(tetrahydroborato-H,H')cobalt

Cited by 42 publications

References 5 publications

Metal–organic layers stabilize earth-abundant metal–terpyridine diradical complexes for catalytic C–H activation

Metal–organic layers stabilize earth-abundant metal–terpyridine diradical complexes for catalytic C–H activation

Anchoring of Silyl Donors on a N‐Heterocyclic Carbene through the Cobalt‐Mediated Silylation of Benzylic CH Bonds

Anchoring of Silyl Donors on a N‐Heterocyclic Carbene through the Cobalt‐Mediated Silylation of Benzylic CH Bonds

Contact Info

Product

Resources

About