Group 3, Lanthanide, and Actinide Metal–Metal Bonds

Oelkers, Benjamin; Kempe, Rhett

doi:10.1002/9783527673353.ch3

Cited by 7 publications

(7 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, their presence introduces the possibility of Ae-(µ-OC)-TM isocarbonyl bonding, which can often occur in preference to Ae-TM bonding. This dilemma has been referred to by Kempe as "the isocarbonyl problem" [15] and has been similarly observed by Marks for the highly oxophilic 5f elements in the pursuit of An-TM bonds. [18] Work in our laboratories has recently led to the report of several structurally authenticated Ae-TM bonded species, including [MgFp 2 (THF)] 2 (6) [12] and [Mg{Co(CO) 3 (PCy 3 )} 2 (THF)] 2 (7), [13] synthesised from the reductive cleavage of Fp 2 and [Co(CO) 3 (PCy 3 )] 2 by a Mg/Hg amalgam.…”

Section: Introductionmentioning

confidence: 78%

See 1 more Smart Citation

Synthesis, characterisation and structural studies of amidinate and guanidinate alkaline earth–transition metal bonded complexes

et al. 2016

View full text Add to dashboard Cite

Reaction of magnesium amidinate complexes of the form [{MesC(NR) 2 }MgBr(OEt 2)] 2 (R = i Pr, Dipp, Mes) with the potassium salts of transition metal anions K[CpFe(CO) 2 ] (K[Fp]) and K[Co(CO) 3 (PCy 3)](THF) 2 gave the complexes {MesC(NR) 2 }MgFp(THF) and {MesC(NR) 2 }Mg{Co(CO) 3 (PCy 3)}(THF). Single crystal X-ray diffraction studies of {MesC(NR) 2 }Mg{Co(CO) 3 (PCy 3)}(THF) for R = i Pr and Dipp confirm these to have Mg-Co bonds in the solid state. Reaction of the structurally similar magnesium guanidinate complex {Me 2 NC(NDipp) 2 }MgI(OEt 2) with the aforementioned transition metal anions and additional K[Co(CO) 3 (PPh 3)](THF) gave the series of complexes [{Me 2 NC(NDipp) 2 }MgFp] 2 , {Me 2 NC(NDipp) 2 }Mg{Co(CO) 3 (PCy 3)}(OEt 2) and {Me 2 NC(NDipp) 2 }Mg{Co(CO) 3 (PPh 3)}(OEt 2). Structural authentication by X-ray crystallography showed [{Me 2 NC(NDipp) 2 }MgFp] 2 to be a very rare example of a base-free alkaline earth-transition bonded complex, having two Mg-Fe bonds. IR and diffusion NMR spectroscopy were carried out to gain further insight into the solid state and solution phase structures.

show abstract

Section: Introductionmentioning

confidence: 78%

“…where M = lanthanide (Ln) or actinide (An)) [15] or early-late heterobimetallics [16] reveals only a handful of metal anions that are routinely exploited for these purposes. These "privileged anions" are [CpM(CO) 2 ] -(M = Fe ("Fp") or Ru ("Rp")), [Cp 2 Re] -, [Co(CO) 4 ]and its monophosphine analogue [Co(CO) 3 (PR 3 )] -.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, characterisation and structural studies of amidinate and guanidinate alkaline earth–transition metal bonded complexes

et al. 2016

View full text Add to dashboard Cite

show abstract

“…The recent emergence of coordination compounds containing metal–metal bonds between transition metals (TMs) and rare earth (RE) elements, that is, the group 3 metals and the lanthanides (Ln), has inspired their use in diverse applications. − For example, TM–RE bonded complexes are currently being explored for single-molecule magnetism. , In the realm of catalysis, multimetallic cooperativity between rare earth ions and transition metals can elicit beneficial activity in both heterogeneous , and cluster − systems by affecting the catalyst stability, electronics, and/or substrate binding affinity. Even so, direct TM–RE bonds, especially those involving lanthanides, are rarely seen in homogeneous catalysis.…”

Section: Introductionmentioning

confidence: 99%

Rare-Earth Supported Nickel Catalysts for Alkyne Semihydrogenation: Chemo- and Regioselectivity Impacted by the Lewis Acidity and Size of the Support

2020

View full text Add to dashboard Cite

Bimetallic catalysts of nickel(0) with a trivalent rare-earth ion or Ga(III), NiML3 (where L is [iPr2PCH2NPh]−, and M is Sc, Y, La, Lu, or Ga), were investigated for the selective hydrogenation of diphenylacetylene (DPA) to (E)-stilbene. Each bimetallic complex features a relatively short Ni–M bond length, ranging from 2.3395(8) Å (Ni–Ga) to 2.5732(4) Å (Ni–La). The anodic peak potentials of the NiML3 complexes vary from −0.48 V to −1.23 V, where the potentials are negatively correlated with the Lewis acidity of the M(III) ion. Three catalysts, Ni–Y, Ni–Lu, and Ni–Ga, showed nearly quantitative conversions in the semihydrogenation of DPA, with NiYL3 giving the highest selectivity for (E)-stilbene. Initial rate studies were performed on the two tandem catalytic reactions: DPA hydrogenation and (Z)-stilbene isomerization. The catalytic activity in DPA hydrogenation follows the order Ni–Ga > Ni–La > Ni–Y > Ni–Lu > Ni–Sc. The ranking of catalysts by (Z)-stilbene isomerization initial rates is Ni–Ga ≫ Ni–Sc > Ni–Lu > Ni–Y > Ni–La. In operando 31P and 1H NMR studies revealed that in the presence of DPA, the Ni bimetallic complexes supported by Y, Lu, and La form the Ni(η2-alkyne) intermediate, (η2-PhCCPh)Ni(iPr2PCH2NPh)2M(κ2-iPr2PCH2NPh). In contrast, the Ni–Ga resting state is the Ni(η2-H2) species, and Ni–Sc showed no detectable binding of either substrate. Hence, the mechanism of Ni-catalyzed diphenylacetylene semihydrogenation adheres to two different kinetics: an autotandem pathway (Ni–Ga, Ni–Sc) versus temporally separated tandem reactions (Ni–Y, Ni–Lu, Ni–La). Collectively, the experimental results demonstrate that modulating a base-metal center via a covalently appended Lewis acidic support is viable for promoting selective alkyne semihydrogenation.

show abstract

“…Developing innovative types of metal–metal linkages has been fascinating scientists for many decades. − Recently, much effort has been devoted to understanding interactions between 4f-block elements and transition metals. , Owing to their significant synthetic challenge, examples of direct lanthanide to transition–metal bonds remain uncommon (Figure ). Note that short distances between lanthanides and transition metals do not necessarily guarantee strong metal–metal bonds, such as the Lu–Pd(0) complex ( 1 ), where metal atoms are held in close proximity by the bridging aminopyridinato ligands .…”

Section: Introductionmentioning

confidence: 99%

Unsupported Lanthanide–Transition Metal Bonds: Ionic vs Polar Covalent?

et al. 2021

View full text Add to dashboard Cite

Lanthanide−transition metal complexes continue to be of interest, not only because of their synthetic challenge but also of their promising magnetic properties. Computational work examining the chemical bonding between lanthanides and transition metals in PyCp 2 Ln-TMCp(CO) 2 (DyPyCp 2 2− = [2,6-(CH 2 C 5 H 3 ) 2 C 5 H 3 N] 2− ) reveals strong Ln−TM dative bonds. Gasphase optimized geometries are in good agreement with experimental structures at the density functional theory (DFT) level with large-core pseudopotentials. From La to Lu, there is a small increase in the bond dissociation energy, as well as a decrease in Ln−Fe bond lengths. Energy decomposition analyses attribute this trend to an increase in the electrostatic contribution from the decreasing bond length and a modest increase in the orbital contribution. The natural bond orbital analysis clearly indicates that 3d 6 "lone pairs" in the [FeCp(CO) 2 ] − fragment act as a Lewis bases donating nearly 0.5 electron to Ln virtual orbitals of mainly d character. The interfragment bonding was also quantified by the quantum theory of atoms in molecules, which indicates that the Ln−Fe bond is more covalent than the Ca−Fe bond in the hypothetical CpCa-FeCp(CO) 2 but less covalent than the Zn−Fe bond in the hypothetical CpZn−FeCp(CO) 2 . Further comparisons suggest that to the [PyCp 2 Ln] + cation the [FeCp(CO) 2 ] − anion appears much like a halide. Overall, these Ln−TM dative bonds appear to have strong electrostatic contributions as well as significant orbital mixing and dispersion contributions.

show abstract

Group 3, Lanthanide, and Actinide Metal–Metal Bonds

Cited by 7 publications

References 55 publications

Synthesis, characterisation and structural studies of amidinate and guanidinate alkaline earth–transition metal bonded complexes

Synthesis, characterisation and structural studies of amidinate and guanidinate alkaline earth–transition metal bonded complexes

Rare-Earth Supported Nickel Catalysts for Alkyne Semihydrogenation: Chemo- and Regioselectivity Impacted by the Lewis Acidity and Size of the Support

Unsupported Lanthanide–Transition Metal Bonds: Ionic vs Polar Covalent?

Contact Info

Product

Resources

About