Synthesis and structure of a π-arene complex of uranium(III) - aluminum chloride

Cesari, M.; Pedretti, U.; Zazzetta, Z.; Lugli, G.; Marconi, W.

doi:10.1016/s0020-1693(00)95960-7

Cited by 92 publications

(47 citation statements)

References 6 publications

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“…Single-point test calculations on 1 À , using atomic positions from the XRD geometry of 1-K, suggest that the m S = 2 system is slightly lower in energy by [16][17][18][19] kJ mol À1 than the m S = 1 system for all four functionals considered here (see the Supporting Information for details). Upon geometry optimization, the total energies of 1 À in one of the two configurations (m S = 2 and m S = 1) in their respective optimized geometries become virtually the same (see the Supporting Information for details), that is, the two electronic configurations cannot be distinguished by the present density functional calculations on energetic grounds alone.…”

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confidence: 92%

“…[15] This chelating ligand system enables d backbonding between uranium and the arene and solubilizes the monoarene complex. [16] We have previously shown that derivatives of the uranium(III) monoarene complex 1 engage in two covalent d bonds with the p* orbitals of the arene base, each partially occupied with a single electron. [17] The nearly reversible reduction observed for 1 at À2.495 V vs. Fc/Fc + at room temperature suggested that this initial reduction product could be isolated and fully characterized under appropriate conditions.…”

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Synthesis and Characterization of a Uranium(II) Monoarene Complex Supported by δ Backbonding

et al. 2014

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The low‐temperature (<−35 °C) reduction of the trivalent uranium monoarene complex [{(Ad,MeArO)3mes}U] (1), with potassium spheres in the presence of a slight excess of 2.2.2‐cryptand, affords the quantitative conversion of 1 into the uranium(II) monoarene complex [K(2.2.2‐crypt)][((Ad,MeArO)3mes)U] (1‐K). The molecular and electronic structure of 1‐K was established experimentally by single‐crystal X‐ray diffraction, variable‐temperature 1H NMR and X‐band EPR spectroscopy, solution‐state and solid‐state magnetism studies, and optical absorption spectroscopy. The electronic structure of the complex was further investigated by DFT calculations. The complete body of evidence confirms that 1‐K is a uranium(II) monoarene complex with a 5f 4 electronic configuration supported by δ backbonding and that the nearly reversible, room‐temperature reduction observed for 1 at −2.495 V vs. Fc/Fc+ is principally metal‐centered.

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Synthesis and Characterization of a Uranium(II) Monoarene Complex Supported by δ Backbonding

et al. 2014

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“…This was followed by the landmark complex uranocene [U(Z 8 22,23 in 1994 and 1995, respectively, and these compounds still constitute the only examples of uranium-cycloheptatrienyl complexes in the literature. The first p-arene complex of uranium, [U(Z 6 -C 6 H 6 )(AlCl 4 ) 3 ], was reported by Cesari et al 24 in 1971, and more recently, diuranium arene inverted sandwich complexes have become prevalent [25][26][27][28][29][30][31][32][33][34][35][36] . However, and in contrast to the d-block, the notable exception that is absent from this series of carbocyclic p-ligands is that of cyclobutadienyl.…”

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Reductive assembly of cyclobutadienyl and diphosphacyclobutadienyl rings at uranium

et al. 2013

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Despite the abundance of f-block-cyclopentadienyl, arene, cycloheptatrienyl and cyclooctatetraenide complexes, cyclobutadienyl derivatives are unknown in spite of their prevalence in the d-block. Here we report that reductive [2 þ 2]-cycloaddition reactions of diphenylacetylene and (2,2-dimethylpropylidyne)phosphine with uranium(V)-inverted sandwich 10p-toluene tetra-anion complexes results in the isolation of inverted sandwich cyclobutadienyl and diphosphacyclobutadienyl dianion uranium(IV) complexes. Computational analysis suggests that the bonding is predominantly electrostatic. Although the c 4 molecular orbital in the cyclobutadienyl and diphosphacyclobutadienyl ligands exhibits the correct symmetry for d-bonding to uranium, the dominant covalent contributions arise from p-bonding involving c 2 and c 3 orbital combinations. This contrasts with uranium complexes of larger arenes and cyclo-octatetraenide, where d-bonding dominates. This suggests that the angular requirements for uranium to bond to a small four-membered ring favours p-bonding, utilizing 5f-instead of 6d-orbitals, over d-bonding that is favoured with larger ligands, where 6d-orbitals can become involved in the bonding.

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“…0.3717(2) 0.7203 (4) 0.3425 (7) 0.7455 (4) 0.2330(9) 0.7548 ( 4 ) 0.1258 (7) 0.7390(4) 0.1297 (6) 0.7143 (4) 0.2353 (7) 0.7048 (4) 0.3447 ( 7) z 0.6 1196f 81 0.27600 0.5 119 ( 2 ) 0.7796 ( 2 ) 0.5522 (2) 0.5996(4) 0.3643 (6) 0.4222 (6) 0.3681 ( 7) 0.2533 (7) 0.1950 ( 6 ) 0.2504 ( 6 ) Atom x Y 0.46 151 9 1 o.oogz(gj 0.2387 ( 9) 0.1539 (7) 0.1445 (6) 0.2441 (6) 0.3532 (6) 0. %60 ( 7) 0.2647 ( 7) 0.…”

Section: Kristall-und Molekiilstrukturmentioning

confidence: 99%

Synthese und Struktur von Bis(mesitylen)gallium(I)‐tetrachlorogallat(III)

1984

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Synthesis and Structure of Bis(mesitylene)gallium(I) Tetrachlorogallate(II1)From solutions of GalGaCI,] in hot 1,3,5-trimethylbenzene a bis-arene complex [C,H3(CH,),],-Ga' GaCI; (I) crystallizes on cooling. Along with analytical and solution NMR spectroscopic data, an X-ray structure determination confirms this formula. In the crystal the Gal cation is situated above the centers of two mesitylene rings mutually inclined by 39.7". The distance from the metal to the ring center is 2.673 A for both hydrocarbons, and is thus shorter than in the analogous benzene complex, but longer than in the hexamethylbenzene complex. The Ga'l'CI; tetrahedra are linked via one chlorine atom each to the Ga' centers of two (C6H3(CH,),],Ga+ moieties with formation of a chainlike coordination polymer. 1 crystallizes in the monoclinic space group Cc (a = 17.713(3), b = 10.856(2), c = 12.959(2) A, = 110.21(1), at -40°C).Den zahllosen Aromatenkomplexen der Ubergangsmetalle stehen nur wenige entsprechende Koordinationsverbindungen der Hauptgruppenelemente gegenuber. Die bekanntesten Beispiele leiten sich von den niederwertigen Elementen der IV. Gruppe, insbesondere von Sn", ab' -@. Einige Strukturen dieser Addukte wurden r6ntgeno-graphisch aufgeklart, wobei sich fur die Metalle eine zentrische Anordnung iiber den aromatischen Ringsystemen ergab. Die theoretische Beschreibung dieser Bindungssituation hatte aber trotzdem von anderen Voraussetzungen auszugehen als bei analog konfigurierten Ubergangsmetall-Komplexen, da bei den IVb-Elementen gefullte dIoUnterschalen vorliegen. Neuere Diskussionen bedienen sich deshalb mit Vorzug des Cluster-Konzepts und betrachten die Grundeinheiten als nido-Korper mit Metall-Apex.

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Synthesis and structure of a π-arene complex of uranium(III) - aluminum chloride

Cited by 92 publications

References 6 publications

Synthesis and Characterization of a Uranium(II) Monoarene Complex Supported by δ Backbonding

Synthesis and Characterization of a Uranium(II) Monoarene Complex Supported by δ Backbonding

Reductive assembly of cyclobutadienyl and diphosphacyclobutadienyl rings at uranium

Synthese und Struktur von Bis(mesitylen)gallium(I)‐tetrachlorogallat(III)

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