High‐Electron‐Density C<sub>6</sub>H<sub>6</sub> Units: Stable Ten‐π‐Electron Benzene Complexes

Diefenbach, Martin; Schwarz, Helmut

doi:10.1002/chem.200500024

Cited by 21 publications

(23 citation statements)

References 34 publications

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“…A DFT study predicted in 2005 that the barium complex of the benzene tetraanion would be stable as an inverse sandwich, Ba2(C6H6), with D6h symmetry (Diefenbach and Schwarz, 2005).…”

Section: Synthesis and Structural Characterization Of Rare Earth Biphmentioning

confidence: 99%

Rare Earth Arene-Bridged Complexes Obtained by Reduction of Organometallic Precursors

Huang

Diaconescu

2014

Including Actinides

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Rare earth chemistry has witnessed remarkable advances in recent years. In particular, ancillary ligands other than cyclopentadienyl derivatives have been introduced to the organometallic chemistry and their complexes exhibit distinct reactivity and properties compared to the metallocene or half-sandwiched analogues. The present chapter reviews arene-bridged rare earth complexes with an emphasis on those compounds obtained by reduction reactions. A particular emphasis is placed on rare earth complexes supported by 1,1′-ferrocenediyl diamides since they show the most diverse chemistry with arenes: fused arenes, such as naphthalene and anthracene, formed inverse-sandwiched complexes, in which the arene is dianionic; weakly conjugated arenes, such as biphenyl, p-terphenyl, and 1,3,5-triphenylbenzene, were unexpectedly reduced by four electrons and led to 6-carbon, 10- electron aromatic systems; on the contrary, (E)-stilbene, which has a carbon-carbon double bond between the two phenyl rings, could only be reduced by two electrons, which were located on the carbon-carbon double bond instead of the phenyl rings.

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“…A DFT study predicted in 2005 that the barium complex of the benzene tetraanion would be stable as an inverse sandwich, Ba2(C6H6), with D6h symmetry (Diefenbach and Schwarz, 2005).…”

Section: Synthesis and Structural Characterization Of Rare Earth Biphmentioning

confidence: 99%

Rare Earth Arene-Bridged Complexes Obtained by Reduction of Organometallic Precursors

Huang

Diaconescu

2014

Including Actinides

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“…[19-21, 23, 30, 50] Only recently, one neutral diuranium inverted-sandwich complex of the formula [Ts Xy U] 2 (m-h 6 :h 6 -C 7 H 8 ) (Ts Xy = HC-(SiMe 2 NAr) 3 , Ar= aryl) has been prepared and was described as a U V -(toluene 4À )-U V complex. [20,51] The possibility of obtaining a stable ten-p-electron arene complex was first predicted by DFT studies for a barium inverted-sandwich complex [52] and very recently theoretical, crystallographic, and spectroscopic evidence of the presence of a benzene tetra-anion with a ten-p-electron aromatic system have been reported for Group 3 inverted-sandwich complexes. [16] Abstract: Two new arene invertedsandwich complexes of uranium supported by siloxide ancillary ligands (2) with stoichiometric amounts of KC 8 yielding a rare family of inverted-sandwich complexes in three states of charge.…”

Section: Introductionmentioning

confidence: 99%

Cation‐Mediated Conversion of the State of Charge in Uranium Arene Inverted‐Sandwich Complexes

Camp

Mougel

Pécaut

et al. 2013

Chemistry A European J

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Two new arene inverted‐sandwich complexes of uranium supported by siloxide ancillary ligands [K{U(OSi(OtBu)3)3}2(μ‐η6:η6‐C7H8)] (3) and [K2{U(OSi(OtBu)3)3}2(μ‐η6:η6‐C7H8)] (4) were synthesized by the reduction of the parent arene‐bridged complex [{U(OSi(OtBu)3)3}2(μ‐η6:η6‐C7H8)] (2) with stoichiometric amounts of KC8 yielding a rare family of inverted‐sandwich complexes in three states of charge. The structural data and computational studies of the electronic structure are in agreement with the presence of high‐valent uranium centers bridged by a reduced tetra‐anionic toluene with the best formulation being UV–(arene4−)–UV, KUIV–(arene4−)–UV, and K2UIV–(arene4−)–UIV for complexes 2, 3, and 4 respectively. The potassium cations in complexes 3 and 4 are coordinated to the siloxide ligands both in the solid state and in solution. The addition of KOTf (OTf=triflate) to the neutral compound 2 promotes its disproportionation to yield complexes 3 and 4 (depending on the stoichiometry) and the UIV mononuclear complex [U(OSi(OtBu)3)3(OTf)(thf)2] (5). This unprecedented reactivity demonstrates the key role of potassium for the stability of these complexes.

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“…[52] A T1 diagnostic value larger than the recommended threshold [53] of T1 = 0.04 indicates that the electronic state is multiconfigurational in nature. Consequently, single reference methods, including our approximate density functional implementation, would most likely fail to describe properly the electronic structure of that state.…”

mentioning

confidence: 98%

Quantum Chemical Study of the Reaction between Ni⁺ and H₂S

2010

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The reaction between the Ni(+) cation and H(2)S is studied by considering both the doublet ground state and the lowest-lying quartet state. For the doublet state the reaction is endothermic, whereas it is exothermic for the quartet state. Both CCSD(T)//B3LYP and B3LYP levels of theory, combined with the triple-zeta quality TZVP++G(3df,2p), predict that there are three spin crossings along the characterized reaction path. The first one is located after the first transition state, and the second and third ones before and after the second transition state. On the quartet potential energy surface, both transition states are close in energy to the reactants, while on the doublet surface both lie quite higher in energy. The doublet and quartet states of the HNiSH(+) four-membered intermediate lie very close in energy and their corresponding electronic configurations are connected by a single electron flip. This suggests that the -SH ligand would not prevent a facile intersystem crossing at this intermediate molecule, in contrast to the larger protection provided by the more electronegative -OH ligand.

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High‐Electron‐Density C₆H₆ Units: Stable Ten‐π‐Electron Benzene Complexes

Cited by 21 publications

References 34 publications

Rare Earth Arene-Bridged Complexes Obtained by Reduction of Organometallic Precursors

Rare Earth Arene-Bridged Complexes Obtained by Reduction of Organometallic Precursors

Cation‐Mediated Conversion of the State of Charge in Uranium Arene Inverted‐Sandwich Complexes

Quantum Chemical Study of the Reaction between Ni⁺ and H₂S

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High‐Electron‐Density C6H6 Units: Stable Ten‐π‐Electron Benzene Complexes

Cited by 21 publications

References 34 publications

Rare Earth Arene-Bridged Complexes Obtained by Reduction of Organometallic Precursors

Rare Earth Arene-Bridged Complexes Obtained by Reduction of Organometallic Precursors

Cation‐Mediated Conversion of the State of Charge in Uranium Arene Inverted‐Sandwich Complexes

Quantum Chemical Study of the Reaction between Ni+ and H2S

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High‐Electron‐Density C₆H₆ Units: Stable Ten‐π‐Electron Benzene Complexes

Quantum Chemical Study of the Reaction between Ni⁺ and H₂S