MatosIMN

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Organometallic Radical Dithiolene Complexes
Geometrical and Electronic Flexibility
Marc Fourmigué Eq. Matière Condensée et
Systèmes Electroactifs (MaCSE)Sciences
Chimiques de Rennes Université Rennes 1, UMR
CNRS 6226 Campus de Beaulieu 35042 RENNES ,
FranceE mail marc.fourmigue_at_univ-rennes1.frht
tp//scienceschimiques.univ-rennes1.fr/macse
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The Dithiolene Ligand a Non-Innocent Ligand
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A Variety of Structures and Stoichiometries
Dithiolene Chemistry, E. I. Stiefel Ed. Prog.
Inorg. Chem. Vol. 52, 2004
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The Dithiolene Ligand in Material Science
Ni(mnt)21- Radical anion Magnetism Ni(tfd)2
1- Radical anion Magnetism
Ni(dmit)2-1,-0.5 Mixed-valence Conductivity
Ni(dddt)21-,0,1 Conductivity
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Heteroleptic Metallocene/Dithiolene Complexes
M Ti, Zr, Hf V, Nb, Ta Mo, W, Re
M Co, Rh, Ir Ni
Fourmigué, M. Coord. Chem. Rev. 1998, 180, 823
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Ti(IV) d0 Cp()2Ti(dithiolene) complexes
CV of Cp2Ti(dddt) at different scan rates 0.1,
2, 20 V s-1
Non-reversible oxidation to the cation except
with the electron-rich Cp and dddt2- ligands at
the highest scan rates
Cp2Ti(dmit)
Guyon, F. Fourmigué, M. Audebert, P. Amaudrut,
J. Inorg. Chim. Acta 1995, 239, 117.
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Geometrical features in Cp()2Ti(dithiolene)
complexes
The folding of the metallacycle is associated
with a mixing of the Cp2Ti LUMO and dithiolene
HOMO fragment orbitals, orthogonal when q 0
but stabilizing in a folded conformation.
J. W. Lauher, R. Hoffmann, J. Am. Chem. Soc.
1976, 98, 1729
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Geometrical features in Cp()2Ti(dithiolene)
complexes
The folding of the metallacycle is correlated
with the DG of the inversion process, as
determined from VT NMR studies
Guyon, F. Lenoir, C. Fourmigué, M. Larsen, J.
Amaudrut, J. Bull. Soc. Chim. Fr. 1994, 131, 217.
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Heteroleptic Metallocene/Dithiolene Complexes
M Ti, Zr, Hf V, Nb, Ta Mo, W, Re
Ce, U
M Co, Rh, Ir Ni
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Uranium/Dithiolene Complexes
Very different folding of the UC2S2 metallacycle
Roger, M. Arliguie, T. Thuéry,P. Fourmigué,
M. Ephritikhine, M. Inorg. Chem. 2005, 44, 594
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Heteroleptic Uranium/Dithiolene Complexes
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Heteroleptic Uranium/Dithiolene Complexes
Roger, M. Belkhiri, L. Thuéry,P. Arliguie, T.
Fourmigué, M. Boucekkine, A. Ephritikhine,
M. Organometallics 2005, 24, 4940.
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Heteroleptic Uranium/Dithiolene Complexes
Cp2U(III)(dddt)- 5f3, quartet spin state
Cp2U(IV)(dddt) 5f2, triplet spin state
U(III)-S 2.77-2.78 Å U(IV)-S 2.63-2.65
Å (2.76 Å)calc (2.64 Å)calc q 51.9
q 56.3 (54.3)calc (55.1)calc
ADF ZORA/TZP
Roger, M. Belkhiri, L. Thuéry,P. Arliguie, T.
Fourmigué, M. Boucekkine, A. Ephritikhine,
M. Organometallics 2005, 24, 4940.
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83 bonding MO s / d / f /Cp2M/dddt 0.0/6.1/
8.1/15.8 /82.9 Cp2U fragment orbitals, allow
the U atom to develop a strong bonding interaction
with the highly distorted dithiolene ligand
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Population analysis
f orbital population Metallic charge U(III),
5f3 3.23 U(III), 5f3 0.69 U(IV),
5f2 3.01 U(IV), 5f2 0.65 Atom-atom overlap
pop U(III), M-S 0.141-0.146 U(IV),
M-S 0.150-0.168 U(III), M-Cp 0.197 U(IV),
M-Cp 0.219
LtoM donation ? in U(IV)
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Heteroleptic Uranium/Dithiolene Complexes
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First U(V) dithiolene species
Arliguie, T. Fourmigué, M. Ephritikhine, M.
Organometallics 2000, 19, 109.
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Geometry optimization
(cot)U(V)(dddt)2-
(cot)U(IV)(dddt)22-
Exo-exo conformation
Exo-endo conformation with short U-(CC)
distance 2.947(7) Å and 2.960(7) Å U-(CC)
bonding interaction ???
ADF ZORA/TZP
L. Belkhiri, T. Arliguie, P. Thuéry, M.
Fourmigué, A. Boucekkine, M. Ephritikhine
Organometallics 2006, 25, 2782
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Electronic structure of U(V) species
(cot)U(V)(dddt)2-
Covalent U-S interactions
??
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Evidence for ?2 U-(CC) interaction in U(V)
species
Hypothetical (cot)U(VI)(dddt)20
Bond order U-(CC) 0.05/0.08 0.02/0.19 0.01/0.1
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The occupied orbital 70 exhibits a U-(CC)
bonding interaction
L. Belkhiri, T. Arliguie, P. Thuéry, M.
Fourmigué, A. Boucekkine, M. Ephritikhine
Organometallics 2006, 25, 2782
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Heteroleptic Metallocene/Dithiolene Complexes
M Ti, Zr, Hf V, Nb, Ta Mo, W, Re
Ce, U
M Co, Rh, Ir Ni
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The intermediate behavior of Cp2Mo(dithiolene)
complexes
0.8 E(V) V vs Ag/AgClO4
0
Fourmigué, M. Lenoir, C. Coulon, C. Guyon, F.
Amaudrut, J.Inorg. Chem. 1995, 34, 4979
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The intermediate behavior of Cp2Mo(dithiolene)
complexes
Variable folding of the MS2C2 metallacycle in
the d1 species
q
0 ? q ? 35
X- q Br- 30.45(4) BF4- 23.21(5) PF6-
0 ReO(dmit)2- 5.6(5) TCNQF4- 10.2(1)
BPW91/LANL2DZ
Fourmigué, M. Domercq, B. Jourdain, I..
Molinié, P. Guyon, F. Amaudrut, J. Chem. Eur.
J. 1998, 4, 1714. Domercq, B. Fourmigué, M. Eur.
J. Inorg. Chem. 2001, 1625 Clérac, R. Fourmigué,
M. Coulon, C. J. Solid State Chem. 2001, 159,
413.
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Analysis of the Molecular Flexibility of the d1
Species
Very shallow energy wells Noticeable heavy atom
effect The molecular geometry is intimately
related to the structural organization Molecules
with variable HOMO
?
?
Domercq, B. Coulon, C. Fourmigué, M. Inorg.
Chem. 2001, 40, 371
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Spin Ladder Systems in the Cp2Mo/W(dmid) TCNQF4
Salts
Two isostructural salts with Mo and W
Strongly associated, magnetically silent
(TCNQF4)22- dimers Dyad association of the
Cp2M(dmid) moieties Ladder-like system
Fourmigué, M. Domercq, B. Jourdain, I. V.
Molinié, P. Guyon, F. Amaudrut, J. Chem Eur.
J. 1998, 4, 1714
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Evolution of the Spin Ladder Characteristics
within the Mo/W Series
T lt T(cmax) c ? T-1/2exp(-D/kt) D J?
- J// J//2/2J?
Dagotto et al. PRB 1992, 45, 5744, Troyer et al.
PRB 1994, 50, 13515
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Evolution within the Mo/W Series
Contributions of the a1 Cp2M fragment orbital
(metal centered) and the b2 p dithiolene
orbital (ligand centered) to the HOMO and
HOMO-1
Stronger metal character in the W than in the Mo
complexes
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The Cp2Mo(dmit)/PF6-, AsF6-, SbF6- System
Disordered octahedral anions Strong
antiferromagnetic interactions Antiferromagnetic
ordering below TNéel HSF influence of dipolar
interactions
Clérac, R. Fourmigué, M. Gaultier, J. Barrans,
Y. Albouy, P. A. Coulon, C. Eur. Phys. J. B
1999, 9, 431
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Mo vs. W S vs. Se
Cp2Mo(dmit)AsF6 Unfolded metallacycle,
q 0 AF ground state with TNéel 9.5(5)
K HSF 6 500 G Cp2W(dmit)AsF6
Unfolded metallacycle, q 0 AF ground state
with TNéel 3.5(5) K HSF 19 000
G (effect of S.O.) Cp2Mo(dsit)AsF6 U
nfolded metallacycle, q 0

Domercq, B. Coulon, C. Fourmigué, M. Inorg.
Chem. 2001, 40, 371.
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Can we induce a folding through the heavy atom
effect ?
Domercq, B. Coulon, C. Fourmigué, M. Inorg.
Chem. 2001, 40, 371.
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A Molecular Spin Ladder in Cp2W(dsit)AsF6
Spin gap (Dspin) in a two-leg ladder c ?
aT1/2exp(-Dspin/kT) Dspin 89 K J// 90 K, J?
165 K ? J///J? 1.8 (t///t?)2
1.4) Troyer, M. et al Phys. Rev. B, 1994, 50,
13515
Intermolecular interactions within the
ladder t// 105 meV t? 90 meV (Extended
Hückel)
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The Neutral Radical Species CpM(dmit)2?, M
Mo, W
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CpM(dmit)2 , M Mo, W
Metal/ligand orbital mixing (BPW91/LANL2DZ)
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CpM(dmit)2 , M Mo, W
3D set of intermolecular interactions ? Antifer
romagnetic ground state
Fourmigué, M. Coulon, C. Adv. Mater. 1994, 6,
948. Domercq, B. Coulon, C. Feynerou,
P. Dentan, V. Robin, P. Fourmigué, M. Adv.
Funct. Mater 2002, 12, 359
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The Antiferromagnetic Ground State in CpM(dmit)2
Weaker interactions with W
Spin density distribution
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Conclusions I
Versatility of open-shell metallocene/dithiolene
complexes Metal localization or ligand
localization (Co, Ni) Stabilization of high
oxidation state (U(V)) Varying metal/ligand
orbital mixing (Mo, W) and SOMOs Very high
flexibility (mutual adaptation to the
counter-ion) Isostructural series Mo vs. W,
dmit vs. dsit vs. dmid Original magnetic
structures (Spin ladder)
Fourmigué, M. Acc. Chem. Res. 2004, 37, 179-186
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Heteroleptic Metallocene/Dithiolene Complexes
M Ti, Zr, Hf V, Nb, Ta Mo, W, Re
Ce, U
M Co, Rh, Ir Ni
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What about CpNi(dithiolene) complexes
R. B. King, 1963 C.
Faulmann, 1996
Syntheses ? Solid State Structures ?
Magnetic properties ?
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Syntheses of CpNi(dithiolene) Complexes
Faulman, C. Delpech, F. Malfant, I. Cassoux,
P. J. Chem. Soc. Dalton Trans. 1996,
2261. Nomura, M. Kajitani M. et al.
Organometallics, submitted
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Syntheses of CpNi(dithiolene) Complexes
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Solution Properties of CpNi(dithiolene) Radical
Complexes
Reversible oxidation and reduction
Absorption in the NIR
M. Nomura, T. Cauchy, M. Geoffroy, P. Adkine, M.
Fourmigué Inorg. Chem. 2006, 45, 8194
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Evolutions within Series
M. Nomura, M. Geoffroy, P. Adkine, M. Fourmigué,
Eur. J. Inorg. Chem. 2006, 5012
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Evolutions within Series
Eox Ered hn (eV) 1.04 V 1.225 1.15
V 1.462 1.28 V 1.666
M. Nomura, M. Fourmigué, New J. Chem. 2007, 31,
528 E. Le Jouanard, M. Fourmigué, T. Cauchy, work
in progress, P64
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Conclusions II
Syntheses of CpNi(dithiolene) Complexes
Solution Properties of CpNi(dithiolene) Radical
Complexes
? Large electrochem. stability window for the
radical ? NIR absorption due to small HOMO-LUMO
gap ? Evolutions within series
mnt/bdt/dmit/dddt ? Evolutions within series
dddt/pddt/bddt
Solid State Properties ?
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Layered structures of CpNi(dmit)? and CpNi(dsit)?
CpNi(dmit) and CpNi(dsit) are isostructural Curi
e-Weiss behavior for T gt 50 K with q - 42 K
AF 3D ground state with TNeel 17 K
M. Fourmigué, N. Avarvari, Dalton Trans. 2005,
1365
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Chain structures of CpNi(dddt)? and CpNi(ddds)?
CpNi(dddt) and CpNi(ddds) are isostructural Curi
e-Weiss behavior for T gt 50 K with qdddt - 46
K, qddds - 36 K Spin chain behavior
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Dimeric structures of CpNi(bdt)? and CpNi(bds)?
CpNi(bdt) and CpNi(bds) are isostructural Single
t/triplet behavior Jbdt/k - 402(4) K, Jbdt
-279 cm-1 Jbds/k - 451(6) K, Jbds -313
cm-1 Coupling through CpCp overlap ???
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A similar dimeric Cp???Cp interaction in
CpNi(adt)?
Dimeric motif with C?H???N hydrogen
bond Absence of short S???S interactions but a
Cp???Cp face-to-face contact, associated with
strong AF interactions Jadt -237 cm-1
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Spin Density Distribution in CpNi(dithiolene)
Complexes
SOMO dt/Ni/Cp
Spin density Variable distribution Sizeable Cp
contribution in CpNi(bdt) and CpNi(adt)
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Calculations of Exchange Interactions in
CpNi(adt)
Considering the following Hamiltonian for a
bimolecular compound
The J value can be expressed as where ELS and
EHS refer to the energies of the Low Spin and
High Spin states of the dimer For CpNi(adt),
Jcalc 167 cm-1 while Jexp -237
cm-1 Calculations with B3LYP, Basis set F.
Weigend, F. Furche, R. Ahlrichs,J. Chem.
Phys.2003,119, 12753
T. Cauchy, E. Ruiz, O. Jeannin, M. Nomura, M.
Fourmigué, Chem. Eur. J. 2007, 13, 8858
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Experimental Evaluation of the Spin Densities

• EPR hyperfine interactions allows for evaluation
  of spin densities but
• No 1H coupling is resolved
• No S coupling can be detected (33S , I 3/2,
  natural abundance 0.75)
• 77Se has a natural abundance of 7.3 and its
  spin number is only ½
• but large line width due to strong SO coupling
• 77Se enrichment in CpNi(bds) and CpNi(dsit)

P. Adkine, P. Grosshans, M. Geoffroy, M. Nomura,
M. Fourmigué, J. Phys. Chem. A 2008, 112, 4067
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Experimental Evaluation of the Spin Densities
Syntheses starting from elemental 77Se (20 /mg,
1 k/reaction)
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Experimental Evaluation of the Spin Densities
CpNi(77bds) g1 2.146 g2 2.110 g3
2.028 77Se-Aiso ()26
CpNi(bds)
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Experimental Evaluation of the Spin Densities
CpNi(bds)
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Application to the Cp???Cp Interaction in
CpNi(bds)
BP86, basis set 1 238.2 cm-1 BP86, basis set
2 226.9 cm-1 Experimental -313 cm-1
basis set 1 C,H,Se aug-cc-PVDZ, Ni TZV
basis set 2 C,H, Se DZVP  Ni TZVPP
P. Adkine, P. Grosshans, M. Geoffroy, M. Nomura,
M. Fourmigué, J. Phys. Chem. A 2008, 112, 4067
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Conclusions III
CpNi(dt) complexes exhibit a variety of overlap
interactions and associated solid state magnetic
properties dt/dt interactions in
CpNi(dddt), in CpNi(mnt) dt/Cp
interactions in CpNi(tfd) Cp/Cp
interactions in CpNi(adt) in CpNi(bdt)
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ACKNOWLEDGMENTS
Enric Canadell (Barcelona) Cp2M(dt) ,
CpM(dt)2 Rodolphe Clérac (Bordeaux) Benoît
Domercq Uranium Complexes Thérèse Arliguie
(Saclay) Lotfi Belkhiri (Constantine) Michel
Ephritikhine Abdou Boucekkine CpNi(dt) Olivi
er Jeannin Eliseo Ruiz (Barcelona) Mitsushiro
Nomura Thomas Cauchy Michel Geoffroy
(Geneva) Emilie LeJouanard