Reactions of Ground State and Electronically Excited Atoms of Main Group Elements:  a Matrix Perspective

Himmel, Hans‐Jörg; Downs, Anthony J.; Greene, Tim M.

doi:10.1021/cr020405x

Cited by 144 publications

(170 citation statements)

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“…Further details about the matrix-isolation technique can be found elsewhere. [46] The experiments were repeated with C 2 D 4 (Sigma-Aldrich, purity 99 %).…”

Section: Resultsmentioning

confidence: 99%

The Electronic Structure of the Tris(ethylene) Complexes [M(C₂H₄)₃] (M=Ni, Pd, and Pt): A Combined Experimental and Theoretical Study

Hebben

Himmel

Eickerling

et al. 2007

Chemistry A European J

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In this article we analyze in detail the electronic properties of the D(3h)-symmetric tris(ethylene) complexes of nickel, palladium, and platinum ([M(C(2)H(4))(3)] M=Ni, Pd, Pt). In the case of [Pd(C(2)H(4))(3)] the analysis is based on new experimental IR and Raman spectra for the matrix-isolated molecules and in all cases on the results of quantum-chemical (DFT) calculations. The experimental spectra collected for [Pd(C(2)H(4))(3)] provide evidence for several previously unobserved vibrational modes, including the in-phase and out-of-phase nu(C-C) and delta(CH(2)) modes, and the in-phase nu(M-C) mode. Special consideration is given to possible inter-ligand interactions. The interaction force constant f(CC,CC) between two C(2)H(4) ligands can be directly estimated from the spectra, and its very small value (0.002 N m(-1)) indicates the absence of any significant inter-ligand interaction. An analysis of the topology of the theoretical electron density distribution, rho(r), and the corresponding Laplacian, nabla(2)rho(r), for [Pd(C(2)H(4))(3)] and its lighter and heavier homologues [Ni(C(2)H(4))(3)] and [Pt(C(2)H(4))(3)], respectively, is in full agreement with the conclusions drawn from the experimental results. The combined experimental and quantum-chemical results provide detailed insights in the electronic properties of these prototypical ethylene complexes.

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“…Further details about the matrix-isolation technique can be found elsewhere. [46] The experiments were repeated with C 2 D 4 (Sigma-Aldrich, purity 99 %).…”

Section: Resultsmentioning

confidence: 99%

The Electronic Structure of the Tris(ethylene) Complexes [M(C₂H₄)₃] (M=Ni, Pd, and Pt): A Combined Experimental and Theoretical Study

Hebben

Himmel

Eickerling

et al. 2007

Chemistry A European J

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“…[17] [18] and we note the special case of neutral and bound Li(NH 4 ), in which the unpaired electron resides in am ixture of Li 3s and NH s*-orbitals. [19] We will investigate the trend in basic and acidic properties along the first group of the Periodic Table (Li, Na, K, Rb,Cs) separately,int he future.…”

Section: This Additional Electron With Respect To [Cso 4 ]mentioning

confidence: 89%

Cesium's Off‐the‐Map Valence Orbital

et al. 2017

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The T d -symmetric [CsO 4 ]+ ion, featuring Cs in an oxidation state of 9, is computed to be am inimum. Cs uses outer core 5s and 5p orbitals to bind the oxygen atoms.T he valence Cs 6s orbital lies too high to be involved in bonding, and contributes to Rydberg levels only.F romamolecular orbital perspective,the bonding scheme is reminiscent of XeO 4 : an octet of electrons to bind electronegative ligands,a nd no low-lying acceptor orbitals on the central atom. In this sense, Cs + resembles hypervalent Xe.Even if we realize that for some heavier elements the border between valence and core orbitals fades, [1] it could still be argued that hard-line distinction is only partially wrong at most;c ome what may,r eactivity would feature the formal valence orbitals in some sort of role.B ut is that unfailingly true?I ti st he first question in this work, in which we theoretically explore [CsO 4 ] + ,amolecule shown in Figure 1.Electrons in core orbitals are often thought of as frozen. Whereas this helps reducing the cost of quantum-chemical calculations,there are cases in which these electrons play as ignificant role in electronic structure and bonding.There exists aprofusion of recent literature on high-pressure effects in elemental solids.S odium, lithium, and aluminum, under high pressures,a ll have their core orbitals overlap.[2] And this happens even for osmium, the most incompressible element. [3] In particular settings,s uch core overlap may push valence electrons to lattice interstitials,s tripping the metal of conductivity,and forming what is referred to as an electride. [4] Direct effects on bonding occur, too:p ressure was shown to turn cesium into ap block element, and mercury into ad 8 transition metal.[5]Cesium fascinates further. In am olecule,i td oes not require extreme conditions to use core orbitals for bonding. Hoffmann and co-workers showed that its occupied 5p orbitals contribute to holding CsF 5 together.[ À ,have received attention too.B ut the literature on these systems reports two distinct oxygen molecules that coordinate to the alkali metal, rather than amolecule of T d symmetry. [9] We start by assessing the thermodynamic and kinetic stability of T d [CsO 4 ] + .C omputation was carried out at ZORA-PBE0/TZ2P,w ith the ADF program.[10] TheP BE0 functional, with inclusion of relativistic effects by ZORA, has been shown to give accurate results for cesium complexes. [11] Calculations predict that T d [CsO 4 ] + is al ocal-minimum equilibrium structure,w ith all Hessian eigenvalues positive. Square-planar D 4h [CsO 4 ] + exists as at ransition state between, and 53.7 kcal mol À1 above,t wo tetrahedral minima with mutually inverted structures. T d [CsO 4 ] + prefers asinglet state-the nearest triplet lies more than 43 kcal mol À1 higher in energy.Itfeatures alarge HOMO-LUMO gap,4.68 eV,as computed at our level of theory.Our minimum of interest is thermodynamically,h ighly unstable towards dissociation, as shown in Figure 2

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“…[40] Very briefly, in a high vacuum apparatus, HCl was passed over liquid Al (at 1000°C) inside a Knudsen-type graphite container. Hence AlCl was formed and the vapor emitted from the cell.…”

Section: Methodsmentioning

confidence: 99%

C−H Activation by AlCl Monomers: Characterization of HAl(Cl)CH₃ as the Product of the Photoactivated Reaction Between AlCl and CH₄ in a Solid Ar Matrix at 12 K

Himmel

2003

Eur J Inorg Chem

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In a solid Ar matrix at 12 K and upon photoactivation AlCl inserts into the C−H bond of CH 4 IntroductionSubvalent compounds of the general formula MX [M ϭ Al, Ga or In, and X ϭ F, Cl, I, or a cyclopentadienyl (Cp) derivative] react readily, when photoactivated, with a number of molecules.[1] Examples include the reaction of AlCl with H 2 to give H 2 AlCl, [2] with O atoms to give OAlCl, [3] with O 2 to give ClAlO 2 [4] or, when the concentration of O 2 is increased, ClAl(O 2 ) 2 , [5] and with HX (X ϭ F, Cl or Br) to give HAl(Cl)X. [6,7] With GaCl [8] and InCl, [9] reactions with H 2 and with HCl afford the hydrides H 2 MCl and HMCl 2 (M ϭ Ga or In), respectively. GaF reacts with O atoms to give OGaF.[10] Finally, matrix-isolated AlCp* reacts with H 2 upon photoactivation to yield H 2 AlCp*. [11] Although these species are generally highly reactive, there are some remarkable differences between AlX, GaX and InX with respect to their reactivities and the structures and composition of the end-products. Whereas AlCl reacts, as already mentioned, upon photoactivation with O 2 [Equation (1)], GaCl or InCl show no matrix reaction, photoactivated or not, with O 2 [Equation (2)]. [12] (1) (2) [a]

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Reactions of Ground State and Electronically Excited Atoms of Main Group Elements: a Matrix Perspective

Cited by 144 publications

References 483 publications

The Electronic Structure of the Tris(ethylene) Complexes [M(C₂H₄)₃] (M=Ni, Pd, and Pt): A Combined Experimental and Theoretical Study

The Electronic Structure of the Tris(ethylene) Complexes [M(C₂H₄)₃] (M=Ni, Pd, and Pt): A Combined Experimental and Theoretical Study

Cesium's Off‐the‐Map Valence Orbital

C−H Activation by AlCl Monomers: Characterization of HAl(Cl)CH₃ as the Product of the Photoactivated Reaction Between AlCl and CH₄ in a Solid Ar Matrix at 12 K

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Reactions of Ground State and Electronically Excited Atoms of Main Group Elements: a Matrix Perspective

Cited by 144 publications

References 483 publications

The Electronic Structure of the Tris(ethylene) Complexes [M(C2H4)3] (M=Ni, Pd, and Pt): A Combined Experimental and Theoretical Study

The Electronic Structure of the Tris(ethylene) Complexes [M(C2H4)3] (M=Ni, Pd, and Pt): A Combined Experimental and Theoretical Study

Cesium's Off‐the‐Map Valence Orbital

C−H Activation by AlCl Monomers: Characterization of HAl(Cl)CH3 as the Product of the Photoactivated Reaction Between AlCl and CH4 in a Solid Ar Matrix at 12 K

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The Electronic Structure of the Tris(ethylene) Complexes [M(C₂H₄)₃] (M=Ni, Pd, and Pt): A Combined Experimental and Theoretical Study

The Electronic Structure of the Tris(ethylene) Complexes [M(C₂H₄)₃] (M=Ni, Pd, and Pt): A Combined Experimental and Theoretical Study

C−H Activation by AlCl Monomers: Characterization of HAl(Cl)CH₃ as the Product of the Photoactivated Reaction Between AlCl and CH₄ in a Solid Ar Matrix at 12 K