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Journal ArticleDOI

Mono(amido-diphosphine) complexes of yttrium: synthesis and x-ray crystal structure of {Y(.eta.3-C3H5)[N(SiMe2CH2PMe2)2]}2(.mu.-Cl)2

01 Sep 1992-Organometallics (American Chemical Society)-Vol. 11, Iss: 9, pp 2967-2969
TL;DR: In this paper, the reaction of allylmagnesium chloride with the bis(amido-phosphine) complex YCl was investigated and the identity of the magnesium byproduct was revealed.
About: This article is published in Organometallics.The article was published on 1992-09-01. It has received 36 citations till now. The article focuses on the topics: Center (category theory).
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TL;DR: 96 Samarium diiodide acted as reducing agent in the reaction with (phenylenebis(3,5-tBu4-salicylidene)iminato)sodium, which resulted in formation of the THF adduct {P2N2}YCH2SiMe3(THF), whereas the THf-free compound could only be isolated as a highly reactive oily material.
Abstract: ion upon treatment with B(C6F5)3 in THF to generate the cationic species [(MAC)Y(CH2SiMe3)][B(C6F5)3(CH2SiMe3)]. However, this salt was found to be highly unstable and could not be isolated as a pure material.97 Fryzuk et al. have developed a remarkable organoyttrium chemistry around the phosphorus-containing macrocycle syn-{P2N2} ({P2N2} ) [PhP(CH2SiMe2NSiMe2CH2)2PPh]). The starting material was the chloride-bridged dimer [{P2N2}Y(μ-Cl)]2, which can be prepared in 95% yield by the reaction of synLi2(THF){P2N2} with YCl3(THF)3 in THF solution. Straightforward metathesis using the very bulky alkyllithium reagent LiCH(SiMe3)2 according to eq 29 (methyl groups on Si omitted for clarity) afforded the monomeric yttrium alkyl species {P2N2}YCH(SiMe3)2 in 92% yield. Use of the less sterically hindered alkyl moiety CH2SiMe3 followed by addition of THF resulted in formation of the THF adduct {P2N2}YCH2SiMe3(THF), whereas the THF-free compound could only be isolated as a highly reactive oily material.98 A quite remarkable samarium alkyl complex of complicated molecular structure was reported by Gambarotta et al.99 Samarium diiodide acted as reducing agent in the reaction with (phenylenebis(3,5-tBu4-salicylidene)iminato)sodium, (3,5tBu4salophen)Na2(THF)3, to give dimeric [Sm2(SBSB)(THF)3]‚2toluene (SB-SB ) C-C bonded 3,5tBu4salophen dimer). The new ligand resulted from the reductive coupling of two imino functional groups of two 3,5-tBu4salophenSm units. Subsequent treatment with MeLi resulted in a novel oxo-bridged dimer (24), featuring alkylation of both samarium atoms and arising from cleavage of the C-C bond connecting the two units, as well as complete reduction of the imine groups of the salophen ligands and THF deoxygenation. In the formula drawing depicted here the bridging phenylene rings are omitted for clarity.99 Carbene complexes of the lanthanide elements have first become available through the use of the stable Arduengo-type carbenes.100,101 Organolanthanide derivatives are readily accessible by adding the heterocyclic carbene ligands to various diand trivalent rare earth complexes such as decamethylsamarocene. Cyclopentadienyl-free derivatives have been obtained by reacting 1,3,4,5-tetramethylimidazol-2-ylidene with the tris(2,2,6,6-tetramethylheptane-3,5-dionato) complexes of yttrium and europium, Ln(THD)3 (Ln ) Y, Eu). The two carbene complexes 25 were isolated as white solids in quantitative yield. The europium complex was structurally characterized by X-ray analysis. Despite the differences in the ionic radii of the two metals 7-coordinate monocarbene adducts are formed in both cases. With 266.3(4) pm the Eu-C distance in (1,3,4,5-tetramethylimidazol-2-ylidene)Eu(THD)3 is comparable to Pr(III)-C and Sm(III)-C distances reported for some isonitrile complexes.102,103 In the 13C NMR spectrum of the yttrium complex the resonance for the former carbene carbon is at δ 199.38 (cf. δ 214 for the free carbene ligand) and shows a 13C-89Y coupling of 33 Hz which indicates that the Y-C bond does not dissociate rapidly on the NMR time scale.101 The bulkier 1,3-diisopropyl-4,5dimethylimidazol-2-ylidene (iPr-Carb) has been used to synthesize a mixed carbene-THF alkyl Lu(CH2SiMe3)3(THF)(Pr-Carb) (26).22d Due to its higher steric demand, the carbene ligand occupies an equatorial position (Lu-C(Carb) ) 249 pm). Somewhat related to the carbene complexes is a highly unusual monomeric samarium bis(iminophosphoranyl) chelate complex which has been reported by Cavell et al.104 Addition of H2C(Ph2PdNSiMe3)2 to a toluene solution of samarium tris(dicyclohexylamide) afforded bright yellow [κ-C,N,N′-C(Ph2Pd NSiMe3)2]Sm(NCy2)(THF) (27). The core of the molecule consists of two nearly planar, fused fourmembered rings with a Sm-C shared edge. With 246.7(4) pm the Sm-C bond length is considerably shorter (10%) than the average samarium-carbon distances, indicating that 27 can be formulated as a carbene complex. Non-Cyclopentadienyl Organolanthanide Complexes Chemical Reviews, 2002, Vol. 102, No. 6 1865

438 citations

Journal ArticleDOI
TL;DR: In this paper, a review of the non-Cp organometallic chemistry of the ligands which have so far been explored for this purpose, commenting on the fine balance of steric and electronic properties necessary to stabilize monomeric, base-free organometall compounds of these metals.

397 citations

Journal ArticleDOI
TL;DR: The reactivity of benzamidinate-stabilized yttrium complexes has been investigated in this paper, showing that they are thermally stable showing no sign of decomposition, ligand or solvent metalation or H/D exchange after hours of 100 degrees C in cyclohexane-d(12) or benzene-d (6).

181 citations

Journal ArticleDOI
TL;DR: In this article, the tris(alkyl) precursors [M(CH2SiMe2R)3(THF)2] (M = Sc, 1-ScR; M = Y, 1YR; R = CH3, Ph) via alkane elimination.

130 citations

Journal ArticleDOI
TL;DR: The use of the centroid of π-bonded carbon atoms to define a coordination position has been shown to be a good descriptor for homoleptic organometallic compounds of transition elements relative to the classical coordination polyhedra as mentioned in this paper.

105 citations