Padova - 05/04/07 A.A. 2006-2007 Opportunità in Chimica VILLAGE: Virtual Italian Laboratory for...

Padova - 05/04/07A.A. 2006-2007

Opportunità in Chimica

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VILLAGE:Virtual Italian Laboratory for Large-scale Applications in a Geographically distribuited Environment.

Padova - 05/04/07A.A. 2006-2007




Agnoli Stefano University of PadovaArmelao Lidia CNR of PadovaBarreca Davide CNR of PadovaBottaro Gregorio CNR of PadovaCasarin Maurizio University of PadovaCorrezzola Claudio University of PadovaEl Habra Naida University of PadovaForrer Daniel University of PadovaGarau Federica University of PadovaGasparotto Alberto University of PadovaGlisenti Antonella University of PadovaGranozzi Gaetano University of PadovaGross Silvia CNR of PadovaMaccato Chiara University of PadovaOrzali Tommaso University of PadovaPandolfo Luciano University of PadovaSambi Mauro University of PadovaSedona Francesco University of PadovaTondello Eugenio University of PadovaVittadini Andrea CNR of Padova

Padova - 05/04/07A.A. 2006-2007




The molecular cluster model coupled to Density Functional Theory.

DV-X: Ellis et al. Chem. Phys. 1973, 2, 41, Ellis et al. J. Chem. Phys. 1976, 65, 3629.Dmol: Delley, B. J. Chem. Phys. 1990, 92, 508, Delley, B. J. Chem. Phys. 1991, 94, 7245.ADF: Baerends et al. J. Comput. Chem. 1992, 99, 84.

Padova - 05/04/07A.A. 2006-2007




Covalency:

noble gas configuration;

Lewis structures;

qualitative valence bond theory.

organic chemistry

crystal field;

ligand field.inorganic chemistry

Molecular Orbital Theories

Padova - 05/04/07A.A. 2006-2007




“Bonding is the degree of interaction between two atoms, which can be described by the amount of covalent mixing of their atomic orbital.”

Solomon et al.

Acc. Chem Res. 2000, 33, 859

Covalency in a spectroscopic sense is related not only to metal-ligand orbital mixing ratios (the “symmetry-restricted covalency”) but also to the distortions of the metal orbitals upon bond formation (the “central-field covalence”)

Padova - 05/04/07A.A. 2006-2007




Ligand K-edge X-ray absorption spectroscopy (XAS) is a new experimental probe of the covalency of a metal-ligand bond.



The principal ligand K-edge XAS experiment and illustrative experimental data for [CuCl4]2- and [ZnCl4]2-.

Padova - 05/04/07A.A. 2006-2007




€

ψ* = 1−2 ⎛ ⎝ ⎜ ⎞

⎠ ⎟ 3Cu d

x2 -y2 − 3Cl p

Cl 1s ψ*

€

Int 1Cl s→ ψ*( ) = const Cl 1s

r r ψ *

2≈ α 2const Cl 1s

r r Cl 3p

2

Ligand K-edge spectroscopy is a direct probe of the covalency of a metal-ligand bond.

Orbital energy diagram showing the ligand pre-edge transition.

Padova - 05/04/07A.A. 2006-2007






Comparison of the electric dipole intensity mechanisms for ligand K-edge transitions and optical charge transfer transitions.

Padova - 05/04/07A.A. 2006-2007




M K-edge: electric dipole forbidden (but quadrupole allowed) 1sM ndM transitions

M L-edge: electric dipole allowed 2pM ndM transitions

L K-edge: electric dipole allowed 1sL npL transitions

Padova - 05/04/07A.A. 2006-2007




Background: Spin-Orbit Energy LevelsBackground: Spin-Orbit Energy Levels

j = 3/2

j = 1/2

j = 1/2

mj = 1/2

mj = 3/2

mj = –1/2

l = 1 (p)

mj = –3/2

mj = 1/2

mj = –1/2

mj = 1/2

mj = –1/2

Spin-Orbit

l = 0 (s)

s = 1/2

s = 1/2

Zeeman

Padova - 05/04/07A.A. 2006-2007




Ti(Ti(55-C-C55HH55)Cl)Cl33 Ti(Ti(55-C-C55HH55))22ClCl22TiClTiCl44

Application of SO-RTD-DFTto closed shell complexes

The interest for this complexes has to be ultimatelytraced back to two factors:

i) the catalytic activity of both mono- and bis-cyclopentadienyl titanium(IV) complexes;

ii) the possible use of titanocene dichloride andits water soluble derivatives as possiblealternatives to t he widely used heavy metalbased anticancer drugs.

Padova - 05/04/07A.A. 2006-2007




Ti K-edge of TiCl4, TiCpCl3, TiCp2Cl2

Kuetgens & Hormes

SIF Conference Proceedings 1990, 25, 59

DeBeer George et al.

J. Am. Chem. Soc. 2005, 217, 667

Padova - 05/04/07A.A. 2006-2007




Cl K-edge

TiCl4, TiCpCl3, TiCp2Cl2

Wen & Hitchcock Can. J. Chem. 1993, 71, 1632

Ti L2,3-edge



J. Am. Chem. Soc. 2005, 217, 667

Padova - 05/04/07A.A. 2006-2007




Background: Spin-Orbit Energy LevelsBackground: Spin-Orbit Energy Levels

j = 3/2

j = 1/2

j = 1/2

mj = 1/2

mj = 3/2

mj = –1/2

l = 1 (p)

mj = –3/2

mj = 1/2

mj = –1/2

mj = 1/2

mj = –1/2

Spin-Orbit

l = 0 (s)

s = 1/2

s = 1/2

Zeeman

Padova - 05/04/07A.A. 2006-2007




-9

-8

-7

-6

-5

-4

-3

-2

Energy (eV)

TiCl4 (Td) TiCpCl3 (Cs) TiCp2Cl2 (C2v)

õúõúõú

õúõú

õú

3e

10t2 21a"+35a'

36a'

22a"

37a'

24a1

16b2

17b1

10a2

25a1

2t1

20a"+34a'

15b2

Correlation diagram of TiCl4, TiCpCl3, and TiCp2Cl2 frontier orbitals

Padova - 05/04/07A.A. 2006-2007




The relativistic two-component

ZORA-TDDFT

This method allows the calculation of excitation energies and intensities for closed shell molecules, including spin–orbit coupling and with full use of symmetry.

F. Wang et al. J. Chem. Phys. 2005, 122, 204103

Padova - 05/04/07A.A. 2006-2007




ZORA-TDDFT

€

ΩFl =ωl2Fl

ωl2 = corresponds to to square of the excitation energies

The oscillator strength fl can be exctracted from Fl

€

Ωiaσ , jbτ =δστδijδab εa −εi( )2+2 εa −εi( )

∂Fia∂P jb

εb −ε j( )

Padova - 05/04/07A.A. 2006-2007




1.5x10-3

1.0

0.5

0.0

49654960495549504945

Excitation Energy (eV)

TiCl4 t2

49654960495549504945


TiCp2Cl2 a1 b1 b2

49654960495549504945


TiCpCl3 a' a"

X

Y

XX' X X'

Padova - 05/04/07A.A. 2006-2007




1.0x10-3

0.8

0.6

0.4

0.2

0.0

4960495849564954495249504948


TiCl4 TiCpCl3 TiCp2Cl2

x

x'

x"

x"

x'

y

z

y'

y"

y

t

-9

-8

-7

-6

-5

-4

-3

-2

Energy (eV)

TiCl4 (Td) TiCpCl3 (Cs) TiCp2Cl2 (C2v)

õúõúõú

õúõú

õú

3e

10t2 21a"+35a'

36a'

22a"

37a'

24a1

16b2

17b1

10a2

25a1

2t1

20a"+34a'

15b2

Padova - 05/04/07A.A. 2006-2007




X'X"

X'

X"

X

3.0x10-3

2.5

2.0

1.5

1.0

0.5

0.0

280828042800


TiCl4

280828042800


TiCpCl3 a' a"

280828042800


a1 b1 b2

TiCp2Cl2

Cl K-edge



J. Am. Chem. Soc. 2005, 217, 667

Padova - 05/04/07A.A. 2006-2007




Ti L2,3-edge

Padova - 05/04/07A.A. 2006-2007




M. Parrinello, Solid State Commun. 1997, 102, 107

FROM SILICON TO RNA: THE COMING OF AGE OF AB INITIO MOLECULAR DYNAMICS

“First principle quantum mechanical calculations are by now considered a sort of new spectroscopy, being widely recognized that the chemical and structural information they provide is often more accessible and likewise reliable than that provided by conventional spectroscopies”

Padova - 05/04/07A.A. 2006-2007




““People want to change the naturalPeople want to change the natural

into the useful unnatural”into the useful unnatural”

Hoffmann, R. Hoffmann, R.

in the Introduction to “in the Introduction to “The newThe new chemistry”chemistry”

Nina Hall ed. Nina Hall ed.

Cambridge University Press, 2000Cambridge University Press, 2000

Padova - 05/04/07A.A. 2006-2007




Perturbations induced by dilute impurities in the electronic structure of a specific host

Casarin et al

J. Mol. Struct. (Theochem) 2003, 631, 11Chem. Phys. Lett. 2004, 392, 146Chem. Phys. Lett. 2005, 405, 459

Padova - 05/04/07A.A. 2006-2007




Phenomena related to the coordination chemistry of surfaces

Casarin et al

J. Phys. Chem. B 2002, 106, 795

Inorg. Chem. 2003, 42, 436

Phys. Chem. Chem. Phys. 2003, 5, 2461

Surf. Sci. 2004, 566, 451

Surf. Sci. 2004, 566, 890

J. Phys. Chem. B 2005, 109, 1652

J. Phys. Chem. B 2005, 109, 12596

J. Phys. Chem. B 2005, 109, 21766

J. Phys. Chem. C submitted

Padova - 05/04/07A.A. 2006-2007




Molecular Models of Extended Solids

Casarin et al.

Inorg. Chem. 2004, 43, 5865Inorg. Chem. 2005, 44, 6225Cryst. Growth Des. 2007, 7, xxx

Padova - 05/04/07A.A. 2006-2007




Cl K-edge XAS spectra of [ZnCl4]2- and D2d-[CuCl4]2-; inset shows the dx

2- y

2 HOMO of D4h-[CuCl4]2-.

Orbital energy diagram showing the ligand pre-edge transition.

1s4

p

Padova - 05/04/07 A.A. 2006-2007 Opportunità in Chimica VILLAGE: Virtual Italian Laboratory for...

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