Lanthanide Heteroatom-Stabilised Alkylidenes: A New Approach to Multiply Bonded Lanthanide Chemistry
Lead Research Organisation:
University of Nottingham
Department Name: Sch of Chemistry
Abstract
One of the most exciting and challenging areas of contemporary lanthanide chemistry (lanthanides are the 14 elements at the bottom of the periodic table) is the isolation of lanthanide alkylidenes (compounds which feature a carbon atom doubly bonded to a lanthanide, Ln=C), and only a very limited number are known. Therefore, enduring fundamental questions regarding the stability, structure, bonding, and reactivity of lanthanide alkylidenes remain. Such species are scarce because they lack sufficiently good orbital interactions to stabilise the Ln=C double bond in the way numerous transition metals can. However, if heteroatoms (phosphorus or silicon) are appended to the alkylidene they can help stabilise the electrons in the Ln=C double bond. This First Grant will build on preliminary results the applicant has obtained, which exploits alkylidene heteroatom stabilisation, and utilises his expertise in lanthanide chemistry, to effect a significant and rapid expansion of this field to address the new chemistry of lanthanide alkylidenes. New lanthanide alkylidenes will be subjected to a detailed structural and spectroscopic interrogation, which will be combined with theoretical computational calculations to comprehensively establish their stability, structure and bonding. The reactivity patterns of these complexes will be screened in reactions which parallel transition metal alkylidene reactions (cycloadditions, Wittig-type). Importantly, the applicants preliminary results include a system which exhibits not only a formal Ln=C double bond, but also a reactive Ln-C single bond. This places two very reactive fragments in close proximity at the same metal centre, and presents a unique opportunity to exploit the synergy resulting from them being harnessed together. We will use this synergy to attempt access to previously unknown structural motifs, such as the first terminal lanthanide imides (Ln=N double bond) and the first lanthanide tetrylenes (Ln=Si and Ln=Ge double bonds). These will be highly interesting inorganic versions of unsaturated organic olefins and allenes (C=C, C=C=C), and given the extensive use of transition metal alkylidenes and imides by academia and industry for the synthesis of fine chemicals, pharmaceutical drugs, and commodity plastic polymers, they promise novel new reactivities.
People |
ORCID iD |
| Stephen Liddle (Principal Investigator) |
Publications
Wooles AJ
(2010)
Lanthanide tri-benzyl complexes: structural variations and useful precursors to phosphorus-stabilised lanthanide carbenes.
in Dalton transactions (Cambridge, England : 2003)
Wooles A
(2010)
Synthesis and Characterization of Dysprosium and Lanthanum Bis(iminophosphorano)methanide and -methanediide Complexes
in Organometallics
Vlaisavljevich B
(2011)
On the nature of actinide- and lanthanide-metal bonds in heterobimetallic compounds.
in Chemistry (Weinheim an der Bergstrasse, Germany)
Patel D
(2011)
Structural and theoretical insights into the perturbation of uranium-rhenium bonds by dative Lewis base ancillary ligands.
in Chemical communications (Cambridge, England)
Patel D
(2012)
f-Element-metal bond chemistry
in Reviews in Inorganic Chemistry
Patel D
(2015)
Comments on reactions of oxide derivatives of uranium with hexachloropropene to give UCl 4
in New Journal of Chemistry
Patel D
(2011)
A formal high oxidation state inverse-sandwich diuranium complex: a new route to f-block-metal bonds.
in Angewandte Chemie (International ed. in English)
Mills DP
(2011)
A delocalized arene-bridged diuranium single-molecule magnet.
in Nature chemistry
Mills DP
(2012)
Synthesis of a uranium(VI)-carbene: reductive formation of uranyl(V)-methanides, oxidative preparation of a [R2C-U-O]2+ analogue of the [O-U-O]2+ uranyl ion (R = Ph2PNSiMe3), and comparison of the nature of U(IV)-C, U(V)-C, and U(VI)-C double bonds.
in Journal of the American Chemical Society
Mills DP
(2010)
Regioselective C-H activation and sequential C-C and C-O bond formation reactions of aryl ketones promoted by an yttrium carbene.
in Journal of the American Chemical Society
Mills DP
(2009)
Synthesis and reactivity of the yttrium-alkyl-carbene complex [Y(BIPM)(CH(2)C(6)H(5))(THF)] (BIPM = {C(PPh(2)NSiMe(3))(2)}).
in Dalton transactions (Cambridge, England : 2003)
Lu E
(2016)
Uranium Metalla-Allenes with Carbene Imido R2 C=U(IV) =NR' Units (R=Ph2 PNSiMe3 ; R'=CPh3 ): Alkali-Metal-Mediated Push-Pull Effects with an Amido Auxiliary.
in Chemistry (Weinheim an der Bergstrasse, Germany)
Lu E
(2014)
The ketimide ligand is not just an inert spectator: heteroallene insertion reactivity of an actinide-ketimide linkage in a thorium carbene amide ketimide complex.
in Angewandte Chemie (International ed. in English)
Lu E
(2015)
Uranium-mediated oxidative addition and reductive elimination
in Dalton Transactions
Lu E
(2014)
Synthesis, characterization, and reactivity of a uranium(VI) carbene imido oxo complex.
in Angewandte Chemie (International ed. in English)
Lu E
(2016)
Uranium-Carbene-Imido Metalla-Allenes: Ancillary-Ligand-Controlled cis-/trans-Isomerisation and Assessment of trans Influence in the R2 C=U(IV) =NR' Unit (R=Ph2 PNSiMe3 ; R'=CPh3 ).
in Chemistry (Weinheim an der Bergstrasse, Germany)
Liddle ST
(2015)
The Renaissance of Non-Aqueous Uranium Chemistry.
in Angewandte Chemie (International ed. in English)
Liddle ST
(2009)
A heterobimetallic gallyl complex containing an unsupported Ga-Y bond.
in Inorganic chemistry
Liddle ST
(2011)
Early metal bis(phosphorus-stabilised)carbene chemistry.
in Chemical Society reviews
Liddle ST
(2009)
Metal-metal bonds in f-element chemistry.
in Dalton transactions (Cambridge, England : 2003)
Liddle S
(2009)
Reactions of [Y(BDI)(I)2(THF)] [BDI={HC(CMeNAr)2}-, Ar=2,6-diisopropylphenyl] with Na[M(Cp)(CO)3] (M=Cr, W): X-ray crystal structures of [{Y(BDI)[Cr(Cp)(CO)3]2(THF)}2] and [W(Cp)(CO)3][Na(THF)2]
in Journal of Organometallic Chemistry
Liddle S
(2009)
Non-traditional ligands in f-block chemistry
in Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences
King DM
(2012)
Synthesis and structure of a terminal uranium nitride complex.
in Science (New York, N.Y.)
Gregson M
(2013)
A cerium(IV)-carbon multiple bond.
in Angewandte Chemie (International ed. in English)
Gregson M
(2016)
Emergence of comparable covalency in isostructural cerium(iv)- and uranium(iv)-carbon multiple bonds.
in Chemical science
Gregson M
(2016)
A monometallic lanthanide bis(methanediide) single molecule magnet with a large energy barrier and complex spin relaxation behaviour.
in Chemical science
Gregson M
(2015)
Covalent Uranium Carbene Chemistry
in Comments on Inorganic Chemistry
Gardner BM
(2012)
Homologation and functionalization of carbon monoxide by a recyclable uranium complex.
in Proceedings of the National Academy of Sciences of the United States of America
Gardner BM
(2011)
The nature of unsupported uranium-ruthenium bonds: a combined experimental and theoretical study.
in Chemistry (Weinheim an der Bergstrasse, Germany)
Gardner BM
(2009)
Synthesis and structure of [{N(CH2CH2NSiMe3)3}URe(eta5-C5H5)2]: a heterobimetallic complex with an unsupported uranium-rhenium bond.
in Chemical communications (Cambridge, England)
Gardner BM
(2011)
An unsupported uranium-rhenium complex prepared by alkane elimination.
in Chemistry (Weinheim an der Bergstrasse, Germany)
Gardner BM
(2009)
A Crystallizable dinuclear tuck-in-tuck-over tuck-over dialkyl Tren uranium complex and double dearylation of BPh(4)(-) to give the BPh(2)-functionalized metallocycle [U{N(CH(2)CH(2)NSiMe(3))(2)(CH(2)CH(2)NSiMe(2)CHBPh(2))}(THF)].
in Journal of the American Chemical Society
Du J
(2023)
31 P Nuclear Magnetic Resonance Spectroscopy as a Probe of Thorium-Phosphorus Bond Covalency: Correlating Phosphorus Chemical Shift to Metal-Phosphorus Bond Order
in Journal of the American Chemical Society
Cornish A
(2010)
Reactions of alkali metal and yttrium alkyls with a sterically demanding bis(aryloxysilyl)methane: Formation of aryloxide complexes by Si-O bond cleavage
in Comptes Rendus Chimie
Cooper OJ
(2010)
Synthesis and structure of [U{C(PPh2NMes)2}2] (Mes = 2,4,6-Me3C6H2): A homoleptic uranium bis(carbene) complex with two formal U=C double bonds.
in Dalton transactions (Cambridge, England : 2003)
Cooper OJ
(2011)
Uranium-carbon multiple bonding: facile access to the pentavalent uranium carbene [U{C(PPh2NSiMe3)2}(Cl)2(I)] and comparison of U(V)=C and U(IV)=C bonds.
in Angewandte Chemie (International ed. in English)
Cooper OJ
(2013)
The nature of the U=C double bond: pushing the stability of high-oxidation-state uranium carbenes to the limit.
in Chemistry (Weinheim an der Bergstrasse, Germany)
Cooper OJ
(2010)
A monomeric dilithio methandiide with a distorted trans-planar four-coordinate carbon.
in Angewandte Chemie (International ed. in English)
Cooper OJ
(2014)
Reactivity of the uranium(IV) carbene complex [U(BIPM(TMS))(Cl)(µ-Cl)2Li(THF)2] (BIPM(TMS) = {C(PPh2NSiMe3)2}) towards carbonyl and heteroallene substrates: metallo-Wittig, adduct formation, C-F bond activation, and [2 + 2]-cycloaddition reactions.
in Dalton transactions (Cambridge, England : 2003)
| Description | Compounds which contain a meta-carbon double bond (alkylidenes = carbenes), where the metal is a transition metal, have many important applications in synthesis and are central to Nobel Prize winning chemistry. However, the corresponding f-block chemistry is poorly developed, but could deliver promising new synthetic applications because of the ability of f-block metals to activate unreactive chemical bonds. This project investigated the synthesis of new f-block carbenes and has begun to investigate their intrinsic reactivity. To do this, we required new precursor molecules. We have prepared these new precursors and they have potential applications for the preparation of rare earth complexes in a wide variety of areas which are of interest to researchers generally. Since the area was poorly developed we have developed several new methodologies to access new f-block carbene compounds. Now we have several synthetic methodologies in hand we have employed these to successfully expand the work from our preliminary results and we have prepared many new rare earth and uranium carbenes which has opened up the area. By preparing rare earth and uranium carbenes we have been able to directly compare the differences in bonding between the rare earths and uranium and have observed significant and important differences in the covalency of metal-carbene bonding. Furthermore, we have demonstrated that the uranium-carbenes perform metallo-Wittig chemistry. However, the corresponding rare earth carbenes exhibit distinct reactivity, namely regioselective C-H bond activations of organic ketones. This activation is followed by C-C and C-O bond formation reactions, which can be controlled, to give more complex organic products that are part of a class of compound which forms a potential basis for the synthesis of antibiotics. By pursuing rare earth and uranium carbenes in parallel in an interweaved project we have been able to elucidate structure-bonding-reactivity relationships and start to apply this knowledge. We have also discovered that some of the uranium carbene complexes can be converted into compounds which display magnetism of purely molecular origin. This is a particularly significant result within the field of nanomagnetism, and could lead to applications in ultra-high density data storage and quantum computing in a broader context. This Project has been extremely successful and cost effective. Most of the original objectives have been achieved, and significant progress has been made towards accomplishing the others. Several new and exciting avenues of research have arisen from this work and these together with the outstanding objectives form part of the future research direction and effort of the PI's research group. This Project provided the basis for subsequent funding from EPSRC, the Royal Society, and a highly competitive and prestigious ERC Starter Grant. This Project has resulted in 13 publications detailing results of major fundamental importance and the 5 highlighted publications are particularly impactful. Furthermore, at least 8 more publications from this work will emerge in the near future. This Project has enabled the PI to become established and internationally recognised in what has become a competitive and vibrant area and 17 conference presentations have been given. This Project has resulted in several fruitful collaborations internationally which will be fostered in the future. Key results have been highlighted in the hugely popular, multi-award winning YouTube project Periodic Videos which has ensured broad dissemination of this work. This Project has been excellent training for the appointed PDRA Dr Mills, who has gone on to be an academic at Manchester. This project also supported several PhDs, whom have all gone on to work in chemical industry or academia. Postscript - Dr Mills was appointed to an academic lectureship position at Manchester University (December 2012) which shows that this grant provided excellent training and supported the academic skills pipeline. In 2016 a paper was published in Chemical Science detailing work founded on this grant, it described a world record energy barrier for a single molecule magnet and gave experimental confirmation of a theory proposed as to how to make single molecule magnets better. |
| Exploitation Route | We have developed the fundamental knowledge of f block carbenes, and more recently this work formed the basis for successful follow-on funding for single molecule magnets that could one day find uses in data storage and quantum computing. |
| Sectors | Chemicals,Digital/Communication/Information Technologies (including Software),Other |
| Description | Designing highly axial lanthanide single molecule magnets |
| Amount | £706,000 (GBP) |
| Funding ID | EP/P002560/1 |
| Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
| Sector | Public |
| Country | United Kingdom |
| Start | 12/2016 |
| End | 11/2019 |
| Description | EPSRC |
| Amount | £270,564 (GBP) |
| Funding ID | EP/G051763/1 |
| Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
| Sector | Public |
| Country | United Kingdom |
| Start | 03/2009 |
| End | 02/2011 |
| Description | EPSRC Established Career |
| Amount | £1,422,792 (GBP) |
| Funding ID | EP/M027015/1 |
| Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
| Sector | Public |
| Country | United Kingdom |
| Start | 10/2015 |
| End | 09/2020 |
| Description | European Commission (EC) |
| Amount | £180,000 (GBP) |
| Funding ID | Marie Curie IIF THOR 297888 |
| Organisation | European Commission |
| Sector | Public |
| Country | European Union (EU) |
| Start | 07/2012 |
| End | 06/2014 |
| Description | European Research Council |
| Amount | £850,000 (GBP) |
| Funding ID | 239621 |
| Organisation | European Research Council (ERC) |
| Sector | Public |
| Country | Belgium |
| Start | 01/2009 |
| End | 09/2014 |
| Description | European Research Council |
| Amount | £1,900,000 (GBP) |
| Funding ID | 612724 |
| Organisation | European Research Council (ERC) |
| Sector | Public |
| Country | Belgium |
| Start | 10/2014 |
| End | 09/2019 |
| Description | High Intensity High Sensitivity X-ray Diffraction Equipment |
| Amount | £1,100,000 (GBP) |
| Funding ID | EP/P001386/1 |
| Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
| Sector | Public |
| Country | United Kingdom |
| Start | 10/2016 |
| End | 10/2021 |
| Description | Royal Society of London |
| Amount | £12,737 (GBP) |
| Funding ID | RG110238 - Equipment Grant |
| Organisation | The Royal Society |
| Sector | Charity/Non Profit |
| Country | United Kingdom |
| Start | 10/2011 |
| End | 09/2012 |
| Description | Royal Society of London |
| Amount | £265,000 (GBP) |
| Funding ID | UF110005 - URF Renewal |
| Organisation | The Royal Society |
| Sector | Charity/Non Profit |
| Country | United Kingdom |
| Start | 10/2012 |
| End | 09/2015 |
| Description | EPR |
| Organisation | University of Manchester |
| Country | United Kingdom |
| Sector | Academic/University |
| PI Contribution | We provide materials for study. |
| Collaborator Contribution | UK EPR service provides multi frequency and temperature experiments to spectroscopically probe our molecules. |
| Impact | Publications in Science, Nature Family, JACS, Angewandte Chemie, see publication list for details. |
| Start Year | 2009 |