Samarium Hydride, Methyl, and Vinyl Complexes Supported by Calix-tetrapyrrole Ring Macrocycle. Thermal Decomposition to Samarium(II)

Dubé, Tiffany; Gambarotta, and Sandro; Yap, Glenn P. A.

doi:10.1021/om9907573

Cited by 57 publications

(24 citation statements)

References 22 publications

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“…159 The stoichiometric reaction of LnCl 3 (THF) x and Li 4 (oepg) gives an enolate complex {Li(THF) 2 }[(oepg)Y-(µ-OCHdCH 2 )Li(THF)] (61oe) for Ln ) Y 160 and a chloride complex (oepg)(Cl)Sm{Li 2 (THF) 3 } (62oe) for Ln ) Sm, which has not been structurally characterized thus far. 161 In contrast to the otherwise observed η: 5 η 1 :η: 5 η 1 bonding fashion the Y atom is η: 5 η 1 :η 1 :η 1 -bonded to the oepg ligand and connected via the enolate group to a Li ion, which is π-bonded to a pyrrole ring. Whereas only one additional reaction was carried out with 61oe, an alkylation which led to the formation of a Li-oepg compound, 62oe, served as a precursor for various subsequent reactions.…”

Section: Complexes Derived From LI 4 (Pg)mentioning

confidence: 94%

“…Treatment with H 2 or PhSiH 3 transforms them into the hydride (oepg)(THF)Sm{Li(THF)} 2 (µ 3 -H) (68oe), which can also be obtained by reaction of 62oe with LiAlH 4 or NaHBEt 3 . 161 In the presence of LiCl the addition of ethylene to the hydride triggers a C-H σ-bond metathetic reaction to recover 67oe. However, this vinyl derivative is temperature sensitive and rapidly decomposes under loss of ethylene to a divalent species from which only the cypg derivative (cypg)(THF)Sm(µ 3-Cl)-{Li(THF)}{Li(THF) 2 } (69cy) was structurally characterized.…”

Section: Complexes Derived From LI 4 (Pg)mentioning

confidence: 99%

“…161 Yet, thorough drying and recrystallization from toluene yields the enolate (cypg)Sm(THF)(Li 2 {Li(THF)}(µ 3 -OCHdCH 2 ) (70cy), the cy analogue of 63cy. 164,165 Both enolates react with acetylene to form different compounds.…”

Section: Complexes Derived From LI 4 (Pg)mentioning

confidence: 99%

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Synthesis and Structural Chemistry of Non-Cyclopentadienyl Organolanthanide Complexes

2002

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Over the years one major challenge has remained in organolanthanide chemistry: the synthesis of homoleptic alkyl and aryl complexes. The simplest organometallic compounds of the rare earths are the species LnR 2 or LnR 3 with the rare earth metals in their common oxidation states Ln 2+ and Ln 3+ which imply the coordination of only two or three ligands to the metal center. This is usually insufficient to meet the lanthanides' demands of steric saturation through high coordination numbers.Hence for a long time, only indirect evidence could be found for the existence of simple homoleptic organolanthanide compounds; the isolation and characterization of compounds belonging to this class were first achieved recently using pentafluorophenyl for Ln 2+ derivatives 12 and very bulky alkyl ligands for Ln 3+ species. [13][14][15] Especially for alkyls, very little structural data are available for compounds without any trimethylsilyl-substituted ligands which generally ensure higher stability. But nevertheless, due to the difficulties of their synthesis and their high reactivity alkyls and aryls still represent an interesting class of compounds. 16 Homoleptic σ-Alkyl ComplexesShortly after the synthesis of the first divalent solvent-free Ln alkyl, [(Me 3 Si) 3 C] 2 Yb, 17 the Eu analogue was prepared similarly by the reaction of EuI 2 and KC(SiMe 3 ) 3 in benzene. 18 It also features the bent structure displayed by the Yb complex but with a slightly smaller C-Eu-C angle (C-Eu-C ) 136°, C-Yb-C ) 137°) and longer Eu-C bonds (Eu-C ) 261 pm, Yb-C ) 249/250 pm). Salt metathesis was then again applied successfully to synthesize the first divalent Sm alkyl, Sm[C(SiMe 3 ) 2 (SiMe 2 OMe)] 2 (THF) Frank T. Edelmann was born in Hamburg, Germany, in 1954. He studied chemistry from 1974 to 1979 at the University of Hamburg, where he obtained his Diplom in 1979 and doctoral degree in 1983. His Ph.D. thesis entitled "The chemistry of the tricarbonyl(fulvene) chromium complexes" was carried out under the supervision of Prof. Ulrich Behrens. This was followed by two years (1983−1985) of postdoctoral research as a Feodor Lynen Fellow of the Alexander-von-Humboldt Foundation in the groups of Professors Josef Takats (

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Section: Complexes Derived From LI 4 (Pg)mentioning

confidence: 94%

Section: Complexes Derived From LI 4 (Pg)mentioning

confidence: 99%

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Synthesis and Structural Chemistry of Non-Cyclopentadienyl Organolanthanide Complexes

2002

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“…Solvents were dried by passing them through a column of Al 2 O 3 under an inert atmosphere prior to use, degassed in vacuo, and transferred and stored under inert atmosphere. [(Et 8 ‐calix‐tetrapyrrole)(CH 3 )Sm III {[Li(thf)] 2 [Li(thf) 2 ]( μ 3 ‐Cl)}],7 [(Et 8 ‐calix‐tetrapyrrole)(thf)Sm III {( μ ‐H)[Li(thf)] 2 }] ⋅ 3 THF,7 [{(Et 8 ‐calix‐tetrapyrrole)(Et 2 O)}Sm II {[Li(thf) 2 ][Li(thf)] 2 ( μ 3 ‐OCH=CH 2 )}] ( 1 b ),5 and [{[−(CH 2 ) 5 −] 4 ‐calix‐tetrapyrrole}[Li(thf)] 4 ]3, 8 were prepared according to literature procedures. High‐purity acetylene (Matheson) was used as received.…”

Section: Methodsmentioning

confidence: 99%

“…Compound 1 a : The crystal structure consists of discrete monomeric units. The samarium atom is surrounded by a calix‐tetrapyrrole ligand which adopted the characteristic basketlike conformation5, 7 (Figure 1). Similar to the case of the previously reported 1 b ,5 the coordination geometry around the samarium atom is distorted pseudo trigonal bipyramidal with two nitrogen atoms of two σ‐bonded pyrrole rings (Sm−N3 2.628(6), Sm−N4 2.861(6) Å) and the oxygen atom of a coordinated solvent molecule (Sm−O3 2.630(6) Å) defining the equatorial plane (O3‐Sm‐N3 143.83(19)°, O3‐Sm‐N4 120.67(19)°, N3‐Sm‐N4 73.28(18)°).…”

Section: Methodsmentioning

confidence: 99%

Reactivity of Calix-Tetrapyrrole SmII and SmIII Complexes with Acetylene: Isolation of an “N-Confused” Calix-Tetrapyrrole Ring

Dubé¹,

Guan²,

Gambarotta³

et al. 2001

Chem. Eur. J.

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The nature of the substituents present on the calix-tetrapyrrole tetra-anion ligand [[R2C(C4H2N)]4]4- (R = [-(CH2)5-]0.5, Et) determines the type of reactivity of the corresponding SmII compounds with acetylene. With R = [-(CH2)5-]0.5, dehydrogenation occurred to yield the nearly colorless dinuclear diacetylide complex [[[[-(CH2)5-]4-calix-tetrapyrrole]SmIII]2(mu-C2Li4)].THF as the only detectable reaction product. Conversely, with R = Et, acetylene coupling in addition to dehydrogenation resulted in the formation of a dimeric butatrienediyl enolate derivative [[(Et8-calix-tetrapyrrole)SmIII[Li[Li(thf)]2(mu-OCH=CH2)]]2(mu,eta2,eta'2-HC=C=C=CH)]. Reaction of the trivalent hydride [(Et8-calix-tetrapyrrole)(thf)SmIII[(mu-H)[Li(thf)]]2 or of the terminally bonded methyl derivative [(Et8-calix-tetrapyrrole)(CH3)SmIII[[Li(thf)]2[Li(thf)2](mu3-Cl)]] with acetylene resulted in a mixture of the carbide [[(Et8-calix-tetrapyrrole)SmIII]2(mu-C2Li4)].Et2O with the dimerization product [[(Et8-calix-tetrapyrrole)SmIII[Li[Li(thf)]2(mu3-OCH=CH2)]]2-mu,eta2,eta'2-HC=C=C=CH)]. The same reaction also yielded a third product, a trivalent complex [[(Et8-calix-tetrapyrrole)SmIII[Li(thf)2]]2], in which the macrocycle was isomerized by shifting the ring attachment of one of the four pyrrole rings.

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Scandium, Yttrium & The Lanthanides: Organometallic ChemistryBased in part on the article Scandium, Yttrium & The Lanthanides: Organometallic Chemistry by R. D. Köhn, G. Kociok‐Köhn, & H. Schumann which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.

Schumann

Fedushkin

2005

Encyclopedia of Inorganic Chemistry

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The group 3 metals scandium and yttrium and the 4f elements lanthanum to lutetium build up a big variety of organometallic compounds, in general with the metal in the oxidation state +3. Most of them are sandwich complexes Cp 3 Ln, Cp 2 LnX, and CpLnX 2 containing unsubstituted or substituted cyclopentadienyl ligands. In addition, cyclopentadienyl‐free organo rare earth compounds, like alkyl or aryl derivatives, alkenyl, allyl, alkynyl, hydrido, and carbene complexes, and organolanthanide compounds with indenyl, fluorenyl, cyclooctatetraenyl, or with heterocyclic ligands are described. Samarium, europium, and ytterbium form reasonable stable organic compounds in the oxidation state +2, whereas only a few rare earth organometallics with the metal in the oxidation state 0, +1, and +4 are known. All organo rare earth complexes are extremely sensitive to oxygen and water. The development of various synthetic methods as well as intensive single‐crystal X‐ray structure investigations made these highly reactive organometallic compounds available for use as organic synthons, efficient catalysts for polymerization, hydrogenation, hydroamination, and hydrosilylation as well as precursors for Metal Organic Chemical Vapor Deposition (MOCVD) and other material science applications.

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Samarium Hydride, Methyl, and Vinyl Complexes Supported by Calix-tetrapyrrole Ring Macrocycle. Thermal Decomposition to Samarium(II)

Cited by 57 publications

References 22 publications

Synthesis and Structural Chemistry of Non-Cyclopentadienyl Organolanthanide Complexes

Synthesis and Structural Chemistry of Non-Cyclopentadienyl Organolanthanide Complexes

Reactivity of Calix-Tetrapyrrole SmII and SmIII Complexes with Acetylene: Isolation of an “N-Confused” Calix-Tetrapyrrole Ring

Scandium, Yttrium & The Lanthanides: Organometallic ChemistryBased in part on the article Scandium, Yttrium & The Lanthanides: Organometallic Chemistry by R. D. Köhn, G. Kociok‐Köhn, & H. Schumann which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.

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