cas 41836-21-9, Tris[N,N-bis(trimethylsilyl)amide]cerium(III)

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Lanthanide(III) Di- and tetra-nuclear complexes supported by a chelating tripodal tris(amidate) ligand
Syntheses, structural, and spectroscopic characterization of multinuclear tris(amidate) lanthanide complexes is described. Addition of K3[N(o-PhNC(O)tBu)3] to LnX3 (LnX3 = LaBr3, CeI3
Brown, Jessie L.,Jones, Matthew B.,Gaunt, Andrew J.,Scott, Brian L.,Macbeth, Cora E.,Gordon, John C.
p. 4064 - 4075
(2015)
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Synthesis, solid state structure, and solution behaviour of the lighter lanthanide bis(trimethylsilyl)amido chlorides, [Ln{N(SiMe3)2}2(THF)(μ- Cl)]2 (Ln = Ce, Nd)
The synthesis of [Ln{N(SiMe3)2}2(THF)(μ-Cl)]2 (Ln = Ce, 1; Nd, 2) by reaction of sodium bis(trimethylsilyl)amide (2 equiv.) with LnCl3 is reported. The same complexes were also isolated from the ligand redistribution reactions of Ln[N(SiMe3)2]3 and LnCl3 (2:1 ratio) in THF at 80°C. The crystal structure of 2, determined by X-ray diffraction, revealed a centrosymmetric dimer with bridging chlorides and pentacoordinate metal centres. 1H NMR studies show that the solid state structure is not maintained in solution. NMR evidence for the presence of Ln[N(SiMe3)2]3 and two other bis(trimethylsilyl)amide containing species, presumably Ln[N(SiMe3)2]Cl2(THF)(x) and Ln[N(SiMe3)2]2Cl(THF)(y), is presented.
Berg, David J.,Gendron, Roland A.L.
p. 454 - 458
(2000)
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A structural investigation of heteroleptic lanthanide substituted cyclopentadienyl complexes
The substituted cyclopentadienyl group 1 transfer agents KCp′′, KCp′′′ and KCptt (Cp′′ = {C5H3(SiMe3)2-1,3}-; Cp′′′ = {C5H2(SiMe3)3-1,2,4}-; Cptt = {C5H3(tBu)2-1,3}-) were prepared by modification of established procedures and the structure of [K(Cp′′)(THF)]∞·THF (1) was obtained. KCp′′ and KCptt were reacted variously with [Ln(I)3(THF)4] (Ln = La, Ce) in 2-1 stoichiometries to afford monomeric [La(Cp′′)2(I)(THF)] (2a·THF) and the dimeric complexes [La(Cp′′)2(μ-I)]2 (2a), [Ce(Cp′′)2(μ-I)]2 (2b) and [Ce(Cptt)2(μ-I)]2 (3). KCp′′′ was reacted with [Ce(I)3(THF)4] to afford the mono-ring complex [Ce(Cp′′′)(I)2(THF)2] (4), regardless of the stoichiometric ratio of the reagents. Complex 4 was reacted with [KN(SiMe3)2] to yield [Ce(Cp′′′)2(I)(THF)] (5), [Ce(Cp′′′){N(SiMe3)2}2] (6) and [Ce{N(SiMe3)2}3] by ligand scrambling. Complexes 1-6 have all been structurally authenticated and are variously characterised by other physical methods.
Ortu, Fabrizio,Fowler, Jonathan M.,Burton, Matthew,Formanuik, Alasdair,Mills, David P.
p. 7633 - 7639
(2015)
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The synthesis, structures and polymorphism of the dimeric trivalent rare-earth 3,5-dimethylpyrazolate complexes [Ln(Me2pz) 3(thf)]2
A variety of rare-earth 3,5-dimethylpyrazolate (Me2pz) complexes have been synthesised by (i) the direct reaction of Hg-activated metal with Me2pzH as a pro-ligand at elevated temperatures, (ii) by redox transmetalation/protolysis with the lanthanoid element, Hg(C6F 5)2, and Me2pzH, and (iii) by protolysis of tris[bis(trimethylsilyl)amido]cerium(III) with Me2pzH. Each product, upon crystallisation from tetrahydrofuran (thf), formed a dimeric complex, [Ln(Me2pz)3(thf)]2 (Ln = La, Ce, Pr, Nd, Ho, Yb, or Lu). Despite the common formulation, two completely different structures were observed in two distinct crystallographic domains of existence , together presumptively spanning the gamut of Ln and Y. For the larger rare-earth ions (La-Pr), there are two terminal η2-Me 2pz ligands and one thf donor on each Ln atom, with the metal atoms being linked by a pair of bridging pyrazolate ligands of an uncommon type (η2:η5), resulting in formal ten-coordination. A Me2pzH complex [Ce(Me2pz)3(Me2pzH)], although not isomorphous, has a similar structure. For the smaller rare-earth elements (Nd-Lu), the bridging is entirely different, with two μ-κ1(N):κ1(N) pyrazolate and two unusual bridging thf ligands. Each Ln atom also has two chelating Me2pz ligands, resulting in formal eight-coordination. Crystallisation of [Nd(Me 2pz)3(thf)]2 from pyridine yields monomeric, nine-coordinate [Nd(Me2pz)3(pyridine)3] with only chelating Me2pz ligands. Contrasting structures and bridging Me2pz groups for Ln = La-Pr and Ln = Nd-Lu are described. Copyright
Deacon, Glen B.,Harika, Rita,Junk, Peter C.,Skelton, Brian W.,Werner, Daniel,White, Allan H.
p. 2412 - 2419
(2014)
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Diethyl ether adducts of trivalent lanthanide iodides
The synthesis and structural characterization of the first molecular complexes of lanthanide iodides supported by the weak-base, diethyl ether, are reported. Single-crystal diffraction studies reveal a conserved [LnI3(mer-Et2O)3
Gompa, Thaige P.,Rice, Natalie T.,Russo, Dominic R.,Aguirre Quintana, Luis M.,Yik, Brandon J.,Bacsa, John,La Pierre, Henry S.
p. 8030 - 8033
(2019)
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Small-Scale Metal-Based Syntheses of Lanthanide Iodide, Amide, and Cyclopentadienyl Complexes as Analogues for Transuranic Reactions
Small-scale reactions of the Pu analogues La, Ce, and Nd have been explored in order to optimize reaction conditions for milligram scale reactions of radioactive plutonium starting from the metal. Oxidation of these lanthanide metals with iodine in ether
Windorff, Cory J.,Dumas, Megan T.,Ziller, Joseph W.,Gaunt, Andrew J.,Kozimor, Stosh A.,Evans, William J.
supporting information
p. 11981 - 11989
(2017/10/10)

Synthesis, characterization, and utility of trifluoroacetic acid lanthanide precursors for production of varied phase fluorinated lanthanide nanomaterials
The synthesis of a series of lanthanide trifluoroacetic acid (H-TFA) derivatives which contain only the TFA and its conjugate acid has been developed. From the reaction of Ln(N(SiMe3)2)3 with an excess amount of H-TFA, the products were identified as: [Ln(μ-TFA)3(H-TFA)2]n (Ln?=?Y, Ce, Sm, Eu, Gd, Tb, Dy), [Ln(μ-TFA)3(μ-H-TFA)]n·solv (Ln·solv?=?Pr·2 H-TFA, H3O+, Ho·2py, Er·py, Yb·py, H-TFA), 3[H][(TFA)La(μ-TFA)3La(TFA)(μ-TFA)2(μc-TFA)2]n ?(H2O) ?(H2O, H-TFA) (La·?(H2O) ?(H2O, H-TFA)), [(k2-TFA)Nd(μ-TFA)3]n·H-py+ (Nd·H-py+), [(py)2Tm(μ-TFA)3]n (Tm), or [Lu(μ-TFA)4Lu(μ-TFA)3·H3O+]n (Lu·H3O+). The majority of samples formed long chain polymers with 3 or 4 μ-TFA ligands. Tm was isolated with py coordinated to the metal, whereas Ho, Er, and Yb were isolated with py located within the lattice. Select samples from this set of compounds were used to generate nanomaterials under solvothermal (SOLVO) conditions using pyridine (py) or octylamine at 185?°C for 24?h. The SOLVO products were isolated as: (i) from py: La – fluocerite (LaF3, PDF 98-000-0214, R?=?9.64%, 35(0) nm), Tb – terbium fluoride (TbF3, PDF 00-037-1487, R?=?4.76%, 21(2) nm), Lu lutetium oxy fluoride (LuOF, PDF 00-052-0779, R?=?8.24%, 8(2) nm); (ii) from octylamine: La – fluocerite/lanthanum oxide carbonate (LaF3, PDF 98-000-0214, R?=?7.47%, 5(0) nm; La2O2(CO3), PDF 01-070-5539, R?=?12.32%, 12(0) nm), Tb – terbium oxy fluoride (TbOF, PDF 00-008-0230, R?=?7.01%, 5(0) nm); Lu – lutetium oxide (Lu2O3, PDF 00-012-0728, R?=?6.52%, 6(1) nm).
Boyle, Timothy J.,Yonemoto, Daniel T.,Sears, Jeremiah M.,Treadwell, LaRico J.,Bell, Nelson S.,Cramer, Roger E.,Neville, Michael L.,Stillman, Gregory A.K.,Bingham, Samuel P.
p. 59 - 73
(2017/05/15)

Cerium(III/IV) formamidinate chemistry, and a stable cerium(IV) diolate
Four new cerium(III) formamidinate complexes comprising [Ce(p-TolForm) 3], [Ce(DFForm)3(thf)2], [Ce(DFForm) 3], and [Ce(EtForm)3] were synthesized by protonolysis reactions using [Ce{N(SiMe3)2}3] and formamidines of varying functionality, namely N,N′-bis(4-methylphenyl) formamidine (p-TolFormH), N,N′-bis(2,6-difluorophenyl)formamidine (DFFormH), and the sterically more demanding N,N′-bis(2,6-diethylphenyl) formamidine (EtFormH). The bimetallic cerium lithium complex [LiCe(DFForm) 4] was synthesized by treating a mixture of [Ce{N(SiHMe 2)2}3(thf)2] and [Li{N(SiHMe 2)2}] with four equivalents of DFFormH in toluene. Oxidation of the trivalent cerium(III) formamidinate complexes by trityl chloride (Ph3CCl) caused dramatic color changes, although the cerium(IV) species appeared transient and reformed cerium(III) complexes and N′-trityl-N,N′-diarylformamidines shortly after oxidation. The first structurally characterized homoleptic cerium(IV) formamidinate complex [Ce(p-TolForm)4] was obtained through a protonolysis reaction between [Ce{N(SiHMe2)2}4] and four equivalents of p-TolFormH. [Ce{N(SiHMe2)2}4] was also treated with DFFormH and EtFormH, but the resulting cerium(IV) complexes decomposed before isolation was possible. The new cerium(IV) silylamide complex [Ce{N(SiMe3)2}3(bda)0.5] 2 (bda=1,4-benzenediolato) was synthesized by treatment of [Ce{N(SiMe3)2}3] with half an equivalent of 1,4-benzoquinone, and showed remarkable resistance towards protonolysis or reduction. Figure ate: The reaction of ate complex [Li(thf)Ce{N(SiHMe 2)2}4 with C2Cl6 gives straightforward access to the homoleptic complex [Ce{N(SiHMe2) 2}4], which engages in protonolysis reactions (see scheme) with formamidines to afford the first CeIV formamidinate species [Ce(p-TolForm)4] (p-TolForm=N,N′-bis(4-methylphenyl) formamidinato).
Werner, Daniel,Deacon, Glen B.,Junk, Peter C.,Anwander, Reiner
p. 4426 - 4438
(2014/05/06)

The synthesis, structures and polymorphism of the dimeric trivalent rare-earth 3,5-dimethylpyrazolate complexes [Ln(Me2pz)3(thf)]2
A variety of rare-earth 3,5-dimethylpyrazolate (Me2pz) complexes have been synthesised by (i) the direct reaction of Hg-activated metal with Me2pzH as a pro-ligand at elevated temperatures, (ii) by redox transmetalation/protolysis with the lanthanoid element, Hg(C6F5)2, and Me2pzH, and (iii) by protolysis of tris[bis(trimethylsilyl)amido]cerium(III) with Me2pzH. Each product, upon crystallisation from tetrahydrofuran (thf), formed a dimeric complex, [Ln(Me2pz)3(thf)]2 (Ln = La, Ce, Pr, Nd, Ho, Yb, or Lu). Despite the common formulation, two completely different structures were observed in two distinct crystallographic domains of existence , together presumptively spanning the gamut of Ln and Y. For the larger rare-earth ions (La-Pr), there are two terminal η2-Me2pz ligands and one thf donor on each Ln atom, with the metal atoms being linked by a pair of bridging pyrazolate ligands of an uncommon type (η2:η5), resulting in formal ten-coordination. A Me2pzH complex [Ce(Me2pz)3(Me2pzH)], although not isomorphous, has a similar structure. For the smaller rare-earth elements (Nd-Lu), the bridging is entirely different, with two μ-κ1(N):κ1(N) pyrazolate and two unusual bridging thf ligands. Each Ln atom also has two chelating Me2pz ligands, resulting in formal eight-coordination. Crystallisation of [Nd(Me2pz)3(thf)]2 from pyridine yields monomeric, nine-coordinate [Nd(Me2pz)3(pyridine)3] with only chelating Me2pz ligands. Contrasting structures and bridging Me2pz groups for Ln = La-Pr and Ln = Nd-Lu are described.
Deacon, Glen B.,Harika, Rita,Junk, Peter C.,Skelton, Brian W.,Werner, Daniel,White, Allan H.
p. 2412 - 2419
(2015/04/27)

Cerium(III) dialkyl dithiocarbamates from [Ce{N(SiMe3)2}3] and tetraalkylthiuram disulfides, and [Ce(κ2-S2 CNEt2)4] from the CeIII precursor; TbIII and NdIII analogues
The synthesis and characterisation of the first neutral cerium dialkyl dithiocarbamate complexes, using a novel oxidative displacement of the amido ligands of [Ce{N (SiMe3)2}3] by tetraalkylthiuram disulfides [R2NC(S)S]2 (R = Me, Et) in thf solution, are reported. In the absence of other donors, the complexes [Ce(κ2-S2CNMe2)3 (thf)2] 2 and Ce(κ2-S2CNEt2)3 3 were obtained. The addition of a polypyridyl ligand allowed easy access to a range of complexes of general formula [Ce(κ2-S2 CNR2)3(L∩L)][R = Me and L∩L = 2,2′-bipy (4), or 4,7-diphenyl-1,10-phenanthroline (6); or R = Et and L∩L = 2,2′-bipy (5)]. Brief exposure of the Ce(III) dithiocarbamate 3 to oxygen gas afforded in high yield the diamagnetic, crystalline Ce(IV) dithiocarbamate [Ce(κ2-S2CNEt2)4] 7. The neodymium (8) and terbium (10) complexes, isoleptic with 2, were prepared from the appropriate 4f metal (Ln) bis(trimethylsilyl)amide [Ln{N(SiMe3)2}3] [Ln = Nd or Tb (9)] and [Me2NC(S)S]2. The structures of the crystalline complexes 2, 4, 6, 7, 9 and 10 have been determined by X-ray crystallography. Some evidence has been obtained for the formation of the cerium(IV) complex Ce{N(SiMe3)2}2 (κ2-S2CNMe2)2. The cerium(IV) complex 7 has the metal coordinated to eight sulfur atoms of four planar chelating S2CNC2 moieties and its geometry is intermediate between dodecahedral and square prismatic; the mean Ce-S bond length of 2.803 A in 7 compares with the 2.950 A in the Ce(III) complex 2.
Hitchcock, Peter B.,Hulkes, Alexander G.,Lappert, Michael F.,Li, Zhengning
p. 129 - 136
(2007/10/03)

Synthesis and characterization of volatile, fluorine-free β-ketoiminate lanthanide MOCVD precursors and their implementation in low-temperature growth of epitaxial CeO2 buffer layers for superconducting electronics
A new class of volatile, low-melting, fluorine-free lanthanide metal-organic chemical vapor deposition (MOCVD) precursors has been developed. The neutral, monomeric Ce, Nd, Gd, and Er complexes are coordinatively saturated by a versatile, multidentate ether-functionalized β-ketoiminato ligand series, the melting point and volatility characteristics of which can be tuned by altering the alkyl substituents on the keto, imino, and ether sites of the ligand. Direct comparison with conventional lanthanide β-diketonate complexes reveals that the present precursor class is a superior choice for lanthanide oxide MOCVD. Epitaxial CeO2 buffer layer films can be grown on (001) YSZ substrates by MOCVD at significantly lower temperatures (450-650 °C) than previously possible by using one of the newly developed cerium β-ketoiminate precursors. Films deposited at 540 °C have good out-of-plane (Δω = 0.85°) and in-plane (Δφ = 1.65°) alignment and smooth surfaces (rms roughness ～ 4.3 A). The film growth rate decreases and the films tend to be smoother as the deposition temperature is increased. High-quality yttrium barium copper oxide (YBCO) films grown on these CeO2 buffer layers by pulsed organometallic molecular beam epitaxy exhibit very good electrical transport properties (Tc = 86.5 K, Jc = 1.08 x 106 A/cm2 at 77.4 K).
Edleman, Nikki L.,Wang, Anchuan,Belot, John A.,Metz, Andrew W.,Babcock, Jason R.,Kawaoka, Amber M.,Ni, Jun,Metz, Matthew V.,Flaschenriem, Christine J.,Stern, Charlotte L.,Liable-Sands, Louise M.,Rheingold, Arnold L.,Markworth, Paul R.,Chang, Robert P. H.,Chudzik, Michael P.,Kannewurf, Carl R.,Marks, Tobin J.
p. 5005 - 5023
(2008/10/08)

A comparative synthetic and structural study of triphenylmethoxide and triphenylsiloxide complexes of the early lanthanides, including X-ray crystal structures of La2(OCPh3)6 and Ce2(OSiPh3)6
La[N(SiMe3)2]3 reacts with 3 equiv of triphenylmethanol in toluene to form the dimer [La(OCPh3)2(μ-OCPh3)]2 (1) in 90% yield. 1 crystallizes in the triclinic space group P1 with a = 12.019 (3) A?, b = 14.287 (2) A?, c = 16.375 (3) A?, α = 73.99 (1)°, β = 85.39 (2)°, γ = 76.07 (2)°, V = 2622.8 (8) A?3, and Dcalcd = 1.34 Mg/m3 for Z = 1. Least-squares refinement on the basis of 10950 observed reflections led to a final RF = 3.7%. Each lanthanum atom in 1 is surrounded by two terminal and two unsymmetrically bridging alkoxide ligands such that the four oxygen donor atoms nearly describe a tetrahedron. The bridging La-O distances are 2.389 (2) and 2.483 (2) A?, and the terminal La-O distances average 2.180 (5) A?. The cerium analogue [Ce(OCPh3)2(μ-OCPh3)]2 (2) can be prepared similarly, and a single-crystal analysis shows it to be isomorphous with 1. Triphenylsilanol reacts with Ln[N(SiMe3)2]3 (Ln = La, Ce) in toluene to form the analogous Ph3SiO complexes [Ln(OSiPh3)2(μ-OSiPh3)]2 (Ln = La (3), Ce (4)). Complex 4 crystallizes from toluene in the triclinic space group P1 with a = 13.766 (2) A?, b = 14.376 (1) A?, c = 14.603 (2) A?, α = 73.34 (1)°, β = 70.45 (1)°, γ = 75.87 (1)°, V = 2573.4 (5) A?3, and A?3 = 1.37 Mg/m3 for Z = 1. Least-squares refinement on the basis of 5599 observed reflections led to a final RF = 6.3%. The structure of 4 is similar to that of 1 except that the four oxygen atoms surrounding each metal center approximate a square-pyramidal geometry which has a carbon atom of one of the arene rings in one basal position. By single-crystal analysis, complex 3 is isomorphous with 4. Complexes 3 and 4 dissolve in THF to form the previously characterized Ln(OSiPh3)3(THF)3 complexes. Compounds 1 and 2 are less soluble than 3 and 4 but dissolve in hot THF to form the more soluble THF adducts, Ln(OCPh3)3(THF)x.
Evans, William J.,Golden, Robert E.,Ziller, Joseph W.
p. 4963 - 4968
(2008/10/08)

On the synthesis of monopentamethylcyclopentadienyl derivatives of yttrium, lanthanum, and cerium
Two routes leading to monopentamethylcyclopentadienyl-yttrium, -lanthanum and -cerium complexes have been explored.Transmetallation of LnCl3(THF)xwith Cp*Li (Cp* = C5Me5) proved useful only in some particular cases.Acid-base reactions of homole
Booij, Martin,Kiers, Niklas H.,Heeres, Hero J.,Teuben, Jan H.
p. 79 - 86
(2007/10/02)

Mono(pentamethylcyclopentadienyl) complexes of cerium(III). Synthesis, molecular structure, thermal stability, and reactivity of (C5Me5)CeX2 (X = 2,6-di-tert-butylphenoxo, CH(SiMe3)2, and N(SiMe3)2) complexes
Reaction of Ce(OAr)31 (1) with LiR (R = C5Me5, 1,3-diphenyl-2-methylindene) affords novel RCe(OAr)2 (R = C5Me5, 2; R = 1,3-diphenyl-2-methylindene, 3) compounds. Metathesis of the remaining aryloxide ligands in 2 with bulky main-group alkyl and amide compounds (LiCH(SiMe3)2 and NaN(SiMe3)2) provide neutral C5Me5CeR2 complexes (R = CH(SiMe3)2,5; R = N(SiMe3)2,6). Compound 5 is a polymerization catalyst for ethylene but not for propylene. Compounds 2 and 6 disproportionate in solution with formation of equilibrium mixtures containing C5Me5CeX2, (C5Me5)2CeX, and CeX3 complexes. Structural studies on 2, 5, and 6 show monomeric, formally five-coordinate compounds in the solid state. Compound 2 crystallizes in the monoclinic space group P21 with α = 9.575 (1) A?, b = 17.026 (2) A?, c = 11.530 (1) A?, β = 112.02 (1)°, and Z = 2. Compound 5 crystallizes in the hexagonal space group P63 with a = 18.477 (2) A?, c = 15.991 (3) A?, and Z = 6. Compound 6 crystallizes in the monoclinic space group P21/c with a = 19.252 (6) A?, b = 13.430 (4) A?, c = 12.503 (3) A?, β = 90.28 (2)°, and Z = 4. All compounds display interesting secondary interactions of the metal with C-H and/or Si-C bonds in the solid state.
Heeres, Hero J.,Meetsma, Auke,Teuben, Jan H.,Rogers, Robin D.
p. 2637 - 2646
(2008/10/08)