Preparation and Structures of Hexaphenyl‐ and Hexatolyltantalates(V)

Kleinhenz, Sven; Schubert, Mario; Seppelt, K.

doi:10.1002/cber.19971300715

Cited by 30 publications

(31 citation statements)

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“…[10] In contrast, a distortion to A is found for all neutral Group 6 species [M(CH 3 ) 6 ] (M Cr, Mo, W), [1,2] and for the cations [Tc(CH 3 À ; however, here the energy gain upon distortion is only % 0.8 kJ mol…”

Section: Introductionmentioning

confidence: 73%

“…The C1-M-C2 angles within a given trigonal face of the prism increase very slightly with increasing overall negative charge, and are very slightly reduced for the 3 6 ]. [10] The C 3v -distorted octahedral arrangements C (Table 4, Figure 1 c) deviate strongly from regular octahedra, except for the dianionic systems which prefer regular D 3d structures (these in turn deviate only by a few degrees from ideal octahedral bond angles). The expanded face of the distorted structures is close to planarity (see C4-M-C5 angles!).…”

Section: B Structuresmentioning

confidence: 96%

“…[6] As [W(CH 3 ) 6 ] is an experimentally accessible, [4,6] neutral homoleptic complex with small and simple monodentate ligands, it serves as the most spectacular prototype for a nonoctahedral hexacoordinate complex with a formal d 2À ion (regular trigonal prismatic, with a D 3h skeleton) [7] or computed structures of the simple hexahydride [WH 6 ] (distorted trigonal prismatic, C 3v ) and related hydride model systems. [1,5,8,9] During the course of the present study, X-ray crystallographical studies of the complex anions [TaR 6 ] À (R Ph, CH 2 Ph) were reported by Kleinhenz et al [10] to have structures close to a regular trigonal prism. Extended solid-state structures with trigonal prismatic metal coordination are well known.…”

Section: Introductionmentioning

confidence: 92%

“…[1] Seven imaginary frequencies are computed for the D 3d structure C of [Hf(CH 3 2À , [7] [TaPh 6 ] À , [10] and [Ta(CH 2 Ph) 6 ] À . [10] In contrast, a distortion to A is found for all neutral Group 6 species [M(CH 3 ) 6 ] (M Cr, Mo, W), [1,2] and for the cations [Tc(CH 3 À ; however, here the energy gain upon distortion is only % 0.8 kJ mol…”

Section: Introductionmentioning

confidence: 99%

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The Nonoctahedral Structures of d0, d1, and d2 Hexamethyl Complexes

Kaupp

1998

Chem. Eur. J.

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Section: Introductionmentioning

confidence: 73%

Section: B Structuresmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

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The Nonoctahedral Structures of d0, d1, and d2 Hexamethyl Complexes

Kaupp

1998

Chem. Eur. J.

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“…2, 3 A number of trigonal prismatic [MR 6 ] qtype complexes have been structurally characterized, including [Li(TMEDA)] 2 [Zr(CH 3 ) 6 ], 6 [M(CH 3 ) 6 ] q (M = W, Re, Nb, Ta; q = 0,À1), 4 [Ta(CRCSitBu 3 ) 6 ] À , 7 [M(C 6 H 5 ) 6 ] 2À (M = Zr, Nb), 8 and [Ta(C 6 H 5 ) 6 ] À . 9 Notably absent from this list, however, are their heavier actinide analogues. This paucity is notable, as structural characterization of [AnR 6 ] q complexes would provide a unique platform to study the involvement of the 6d and 5f orbitals in An-C bonds.…”

mentioning

confidence: 99%

Synthesis, structure and bonding of hexaphenyl thorium(iv): observation of a non-octahedral structure

et al. 2016

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We report herein the synthesis of the first structurally characterized homoleptic actinide aryl complexes, [Li(DME) 3 ] 2 [Th(C 6 H 5 ) 6 ] (1) and [Li(THF)(12-crown-4)] 2 [Th(C 6 H 5 ) 6 ] (2), which feature an anion possessing a regular octahedral (1) or a severely distorted octahedral (2) geometry.The solid-state structure of 2 suggests the presence of pseudo-agostic ortho C-HÁ Á ÁTh interactions, which arise from r(C-H) -Th(5f) donation. The non-octahedral structure is also favoured in solution at low temperatures.High-valent homoleptic transition metal complexes of the type [MR 6 ] q (R = alkyl, aryl; q = 0, À1, À2) have proven to be incredibly useful for exploring the nature of the M-C bond. [1][2][3][4][5] In particular, the observation of a trigonal prismatic structure for these complexes, as opposed to the more common octahedral geometry, is considered strong evidence for the involvement of the d orbitals in the metal-carbon bonds. 6 ]. 12,13 The latter was oxidized in situ to U(CH 2 SiMe 3 ) 6 , which was characterized using 13 C and 1 H NMR spectroscopies, accompanied by relativistic DFT calculations of NMR chemical shifts. 16 In each uranium example, an octahedral geometry was observed, which is perhaps not surprising, as significant f-orbital participation in bonding tends to favor an octahedral geometry. 17 In contrast, d orbital involvement in Th-C bonding is expected to be more significant than f orbital participation, 18,19 and therefore the observation of a trigonal prismatic structure should be more likely for this element relative to the other actinides. 10 Given this consideration, we endeavored to synthesize and structurally characterize the homoleptic actinide-aryl complex, [Th(C 6 H 5 ) 6 ] 2À , by reacting ThCl 4 with an excess of phenyl lithium.Addition of 8 equiv. of PhLi to a THF solution of ThCl 4 (DME) 2 results in the formation of a white solid and a dark amber solution. Isolation of this amber material, followed by recrystallization from concentrated DME, afforded [Li(DME) 3 ] 2 [Th(C 6 H 5 ) 6 ] (1) as a pale yellow crystalline material in 56% yield (Scheme 1). Complex 1 is thermally unstable at room temperature (RT), both as a solid and in solution, but is stable for up to 2 weeks as a solid at À25 1C. It is insoluble in hexane, aromatic solvents, and diethyl ether, but very soluble in THF and DME. Its 1 H NMR spectrum in THF-d 8 at RT reveals resonances at 7.61 ppm, 7.00 ppm and 6.79 ppm in the ratio of 2 : 2 : 1, corresponding to the ortho, meta, and para protons of the phenyl ring, respectively. In addition, there is a single resonance in its 7 Li{ 1 H} NMR spectrum at 2.60 ppm. The 13 C{ 1 H} NMR spectrum in THF-d 8 exhibits a key fingerprint resonance at 220.5 ppm, which corresponds to the ipso-carbon, as also confirmed by our relativistic DFT calculations of the NMR chemical shifts (cf. Table S2 in the ESI †). This resonance is shifted notably downfield from the corresponding 13 C-ipso shifts in related Ti, Zr, and Hf aryl complexes (which typically appear between 183 an...

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Im Niemandsland der Sechsfach-Koordination bei d0-Übergangsmetallkomplexen: Strukturvorhersagen für [WCl5CH3], [WCl4(CH3)2] und [WCl3(CH3)3]

Kaupp

1999

Angewandte Chemie

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Ungewöhnliche Strukturen zwischen Oktaeder und trigonalem Prisma wurden in Dichtefunktionalrechnungen an den „einfachen”︁ sechsfach koordinierten d0‐Titelkomplexen gefunden. Während für [WCl5CH3] ein verzerrtes Oktaeder noch eine etwas niedrigere Energie aufweist als ein Prisma, tauchen für [WCl4(CH3)2] intermediäre Strukturen auf (siehe Abbildung). Im Falle von [WCl3(CH3)3] sind prismatische Anordnungen bereits günstiger. Diese und viele verwandte Komplexe sollten experimentell zugänglich sein.

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Preparation and Structures of Hexaphenyl‐ and Hexatolyltantalates(V)

Cited by 30 publications

References 21 publications

The Nonoctahedral Structures of d0, d1, and d2 Hexamethyl Complexes

The Nonoctahedral Structures of d0, d1, and d2 Hexamethyl Complexes

Synthesis, structure and bonding of hexaphenyl thorium(iv): observation of a non-octahedral structure

Im Niemandsland der Sechsfach-Koordination bei d0-Übergangsmetallkomplexen: Strukturvorhersagen für [WCl5CH3], [WCl4(CH3)2] und [WCl3(CH3)3]

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