The nature of metal–metal bond of the dimetallocene complexes [M2(η5-C5R5)2] (M=Zn, Cd, Hg; R=H, Me): An energy decomposition analysis

2007 ◽  
Vol 805 (1-3) ◽  
pp. 127-132 ◽  
Author(s):  
Yuhe Kan
Keyword(s):  
Decomposition Analysis ◽  
Energy Decomposition Analysis ◽  
Energy Decomposition ◽  
Metal Bond ◽  
Metal Metal

On the nature of homo- and hetero-dinuclear metal–metal quadruple bonds — Analysis of the bonding situation and benchmarking DFT against wave function methods

2010 ◽  
Vol 88 (11) ◽  
pp. 1079-1093 ◽  
Author(s):  
Nozomi Takagi ◽  
Andreas Krapp ◽  
Gernot Frenking
Keyword(s):  
Ab Initio ◽  
Dissociation Energy ◽  
Density Functional ◽  
Decomposition Analysis ◽  
Bond Distance ◽  
Basis Sets ◽  
Energy Decomposition Analysis ◽  
Generalized Gradient ◽  
Metal Bond ◽  
Metal Metal

Homo- and hetero-dimetallic (d–d)8 analogues of the formally quadruply bonded [Re2Cl8]2– system with the general formula [MM′Cl8]x (M, M′ = Tc, Re, Ru, Os, Rh, Ir and x = –2, –1, 0, +1, +2) have been calculated with the density functional theory (DFT) functionals SVWN, BLYP, BP86, PBE, OLYP, OPBE, HCTH, B3LYP, O3LYP, X3LYP, BH&HLYP, TPSS, VSXC, TPPSh, and ab initio methods (CASPT2, CCSD(T)) using basis sets of triple-ζ quality. The performance of the functionals for the description of the metal–metal bond distance and the bond dissociation energy as well as the singlet–triplet gap was evaluated with respect to ab initio data at the CASPT2 level. Generally, the generalized gradient approximation (GGA) functionals, BLYP, BP86, and PBE, show good performance in the description of the metal–metal bond distance and for the dissociation energy. Hybrid functionals are not to be used for compounds of the type discussed here as they lead to increasingly too short and too weak bonds with the amount of exact exchange included. All functionals underestimate the singlet–triplet gap, with the GGA functionals BLYP, BP86, PBE being the closest to the CASPT2 values. The bonding situations of the [MM′Cl8]x compounds were analyzed at the DFT level (BP86) using the natural bond orbital (NBO) method and the energy decomposition analysis. The M–M bond in homodimetallic compounds, [MMCl8]x, becomes weaker from group 7 to group 8 to group 9 metals and the bond is weaker for 4d metal systems than for 5d transition metal compounds. The M–M bonds have approximately 50% covalent and 50% electrostatic character and the covalent contribution is dominated by the π orbitals, whereas the δ orbitals do not contribute significantly to the covalent bonding. Heterodimetallic systems, [MM′Cl8]x, have significantly stronger metal–metal bonds than the homodimetallic compounds. This comes from weaker Pauli repulsion and stronger electrostatic attraction. The most stable heterodimetallic bonds are observed for 5d–5d metal pairs.

scholarly journals Energy decomposition analysis of single bonds within Kohn–Sham density functional theory

2017 ◽  
Vol 114 (48) ◽  
pp. 12649-12656 ◽  
Author(s):  
Daniel S. Levine ◽  
Martin Head-Gordon
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Decomposition Analysis ◽  
Spin Coupling ◽  
Energy Decomposition Analysis ◽  
Spin Projection ◽  
Chemical Bonds ◽  
Energy Decomposition ◽  
Functional Theory ◽  
Metal Metal

An energy decomposition analysis (EDA) for single chemical bonds is presented within the framework of Kohn–Sham density functional theory based on spin projection equations that are exact within wave function theory. Chemical bond energies can then be understood in terms of stabilization caused by spin-coupling augmented by dispersion, polarization, and charge transfer in competition with destabilizing Pauli repulsions. The EDA reveals distinguishing features of chemical bonds ranging across nonpolar, polar, ionic, and charge-shift bonds. The effect of electron correlation is assessed by comparison with Hartree–Fock results. Substituent effects are illustrated by comparing the C–C bond in ethane against that in bis(diamantane), and dispersion stabilization in the latter is quantified. Finally, three metal–metal bonds in experimentally characterized compounds are examined: a MgI–MgI dimer, the ZnI–ZnI bond in dizincocene, and the Mn–Mn bond in dimanganese decacarbonyl.

scholarly journals Direct estimate of the internal π-donation to the carbene centre within N-heterocyclic carbenes and related molecules

2015 ◽  
Vol 11 ◽  
pp. 2727-2736 ◽  
Author(s):  
Diego M Andrada ◽  
Nicole Holzmann ◽  
Thomas Hamadi ◽  
Gernot Frenking
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Decomposition Analysis ◽  
Heterocyclic Carbenes ◽  
Energy Decomposition Analysis ◽  
Energy Decomposition ◽  
Direct Estimate ◽  
Functional Theory ◽  
Bonding Analysis

Fifteen cyclic and acylic carbenes have been calculated with density functional theory at the BP86/def2-TZVPP level. The strength of the internal X→p(π) π-donation of heteroatoms and carbon which are bonded to the C(II) atom is estimated with the help of NBO calculations and with an energy decomposition analysis. The investigated molecules include N-heterocyclic carbenes (NHCs), the cyclic alkyl(amino)carbene (cAAC), mesoionic carbenes and ylide-stabilized carbenes. The bonding analysis suggests that the carbene centre in cAAC and in diamidocarbene have the weakest X→p(π) π-donation while mesoionic carbenes possess the strongest π-donation.

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