Theoretical Investigation on the
Homoleptic [(NO)2Fe(NO)2]and Related Dinitrosyl-iron Complexe
Department of Biological Science and Technology
Institute of Bioinformatics and Systems Biology
National Chiao Tung University
TAIWAN
Jen-Shiang K. Yu
at
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January 25, 2013
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Dinitrosyl-iron Complexes (DNIC)
L1L2Fe(NO)2
The Coordination Chemistry of NO
In the 1980s NO was discovered to be one of the
most important physiological regulators, playing
a key role in signal transduction and cytotoxicity,
possibly one of the biggest surprises in biological chemistry in recent times.
Like CO and CN-, NO bound irreversibly to metal
centers and therefore functioned as a poison,
particular with respect to respiratory processes.
MO diagram of stable free radical •NO
Biological Significance of Nitrogen Monoxides
•NO is isoelectronic with the dioxygen
monocation (O2+), and NO+ is isoelectronic
with CO and CN-, while NO- is isoelectronic
with O2 with a triplet ground state.
Accounts for the continuing interest in the study of certain
types of metal nitrosyl complexes which have structural
and electronic analogies with biological oxygen activators.
Medical application regarding NO include
vasodilation, neuronal transmission,
inflammation, immune system response and
cancer remedy.
Possible resonance forms of Metal-NO bonds
J. A. McCleverty, Chem. Rev. 104, 403-418, (2004).
The p-backbonding
electron donation
The dp—p* interaction bonding description is very similar to
that between CO and metals.
However, as NO is more electronegative than CO, it is a better
electron acceptor than CO. Furthermore, within the M—N—O
group, the metal-nitrogen bond is usually strong.
Target Dinitrosyl-iron complexes (DNIC)
[(NO)2Fe(NO)2][(N3)2Fe(NO)2][ I2Fe(NO)2]-
[1]
[2]
[3]
DNIC
DNIC
DNIC
DNIC
[1]
Lin, Z.-S.; Chiou, T.-W.; Liu, K.-Y.; Hsieh, C.-C.; Yu, J.-S. K.; Liaw, W.-F. Inorg. Chem. 2012,
51, 10092-10094.
[2]
Tsai, M.-L.; Hsieh, C.-H.; Liaw, W.-F. Inorg. Chem. 2007, 46, 5110-5117.
[3]
Bryar, T.R.; Eaton, D.R. Can. J. Chem. 1992, 70, 1917-1926.
Experimental Syntheses of DNICs
• [(NO)2Fe(NO)2]-
• [(N3)2Fe(NO)2]-
• [(I)2Fe(NO)2][Fe(CO)3(NO)]- + MeI + cyclo-octatetraene → [(I-)2Fe(NO)2] -
Computational aims
• To reproduce the geometrical features of
DNIC compounds in X-ray crystals.
• Charge and spin analyses based on the
above converged structures.
• Vibrational frequencies, especially the N-O
vibration modes.
• Spectral assignments to experimental UV
absorptions.
Methodologies
• Broken-Symmetry Density Functional
Theories (BS-DFT)
• SAC-CI
• Multi-configuration methods (CASSCF)
Dinitrosyl Iron Complexes Relevant to
Rieske Cluster Nitrosylation:
A Broken-Symmetry DFT Study
Zachary J. Tonzetich, Loi H. Do, and Stephen J. Lippard,
J. Am. Chem. Soc. 2009, 131, pp.7964–7965.
“Broken Symmetry” DFT Study on Fe(NO)2(nacnac) model
nacnac=[(phenyl)NC(Me)2]2CH-
Comparison among functionals
S. Ye and F. Neese,
J. Am. Chem. Soc. 2010,
132, pp.3646–3647.
Geometry optimizations of [(NO)2Fe(NO)2]Direct SAC-CI SD-R / LANL2DZ ECP on Fe,
aug-cc-pVDZ on N, O.
v.s. “Broken-Symmetry” TPSSh/def2-TZVP
[(NO)2Fe(NO)4]-
Symmetry
Fe1-N1
Fe1-N2
Fe1-N3
Fe1-N4
N1-O1
N2-O2
N3-O3
N4-O4
Fe1-N1-O1
Fe1-N2-O2
Fe1-N3-O3
Fe1-N4-O4
Exptl.[1]
C1
1.695
1.719
2.008
2.045
1.175
1.154
1.387
1.281
163.1
161.0
106.8
113.2
TPSSh
SAC-CI (A')
C1
1.739
1.637
1.928
1.750
1.197
1.187
1.205
1.198
152.1
179.0
122.8
154.8
Cs
1.688
1.688
1.987
1.970
1.175
1.175
1.296
1.278
162.9
162.9
104.6
100.5
Linear Radical
Bent Anion
Charge and spin analyses of [(NO)2Fe(NO)2]Direct SAC-CI SD-R / LANL2DZ ECP on Fe,
aug-cc-pVDZ on N, O.
v.s. “Broken-Symmetry” TPSSh/def2-TZVP
TPSSh/def2-TZVP
Fe1
N1
O1
N1 + O1
N2
O2
N2 + O2
N3
O3
N3 + O3
N4
O4
N4 + O4
Charge
0.239
0.036
-0.336
-0.300
0.028
-0.348
-0.320
-0.018
-0.289
-0.307
0.021
-0.333
-0.312
Spin Density (e )
-0.849
0.605
0.371
0.975
-0.169
-0.074
-0.243
-0.032
-0.006
-0.037
0.723
0.430
1.153
SAC-CI
Charge
0.846
0.290
-0.558
-0.269
0.290
-0.558
-0.269
-0.027
-0.650
-0.678
-0.067
-0.564
-0.631
Spin Density (e )
0.000
0.053
0.040
0.094
0.053
0.040
0.094
0.027
0.004
0.031
0.002
0.005
0.008
Linear
Radical
Bent
Anion
Charge analysis based on SP calculation at
CASSCF(7,7)/aug-cc-PVDZ (SAC-CI geometry)
Fe1
N1
O1
N1 + O1
N2
O2
N2 + O2
N3
O3
N3 + O3
N4
O4
N4 + O4
Fe1
N1
O1
TPSSh/def2-TZVP
Charge
Spin Density (e )
0.239
-0.849
0.036
0.605
-0.336
0.371
-0.300
0.975
0.028
-0.169
-0.348
-0.074
-0.320
-0.243
-0.018
-0.032
-0.289
-0.006
-0.307
-0.037
0.021
0.723
-0.333
0.430
-0.312
1.153
Charge
0.846
0.290
-0.558
-0.269
0.290
-0.558
-0.269
-0.027
-0.650
-0.678
-0.067
-0.564
-0.631
SAC-CI
Spin Density (e )
0.000
0.053
0.040
0.094
0.053 Linear
0.040 Radical
0.094
0.027
0.004
0.031
0.002 Bent
0.005 Anion
0.008
s
6.50174
3.74704
4.03185
p
11.82088
3.01564
4.44513
d
6.02086
0.04240
0.07491
f
0.10630
0.00000
0.00000
g
0.00000
0.00000
0.00000
Total
24.44979
6.80508
8.55189
3.74704
4.03185
3.01564
4.44513
0.04240
0.07491
0.00000
0.00000
0.00000
0.00000
6.80508
8.55189
3.81184
4.07795
3.34175
4.60341
0.03329
0.04202
0.00000
0.00000
0.00000
0.00000
7.18687
8.72338
3.76909
4.07807
3.32817
4.66756
0.04116
0.04198
0.00000
0.00000
0.00000
0.00000
7.13842
8.78761
N1 + O1
N2
O2
N2 + O2
N3
O3
N3 + O3
N4
O4
N4 + O4
Charge
1.55021
0.19492
-0.55189
-0.35697
0.19492
-0.55189
-0.35697
-0.18687
-0.72338
-0.91025
- 0.13842
-0.78761
-0.92603
Electron occupation
in the active space:
occ=
occ=
occ=
occ=
occ=
occ=
occ=
1.4550
1.1829
1.0108
0.9984
0.9534
0.8715
0.5281
E= -0.0254
E= -0.0476
E= 0.0274
E= 0.0617
E= 0.0741
E= 0.0126
E= 0.1439
However, CASSCF failed to optimize for
the geometry of [(NO)2Fe(NO)2]-
• Although CASSCF charge analysis is
correct and the digits are significantly better
than SAC-CI, the geometry optimization at
CASSCF cannot converge.
• Optimization at CASSCF level tends to
dissociate three of the Fe—NO bonds.
• Higher order of MC correlation method
such as CASPT2 is not computationally
faster than direct SAC-CI.
CASSCF: out of OPT cycles (50)
The geometry tends to deform from
tetrahedral into trigonal pyramidal.
SAC-CI calculation for open-shell radicals
Four schemes to treat doublet radicals:
CationDoublet （Ⅰ）
RHF
SAC
AnionDoublet （Ⅱ）
SAC-CI
CationDoublet, AddElectron, ROHF （Ⅲ）
ROHF
SAC
SAC-CI
RHF
SAC
SAC-CI
AnionDoublet,SubElectron,ROHF （Ⅳ）
ROHF
SAC
SAC-CI
Key-point:
・ Use SAC to calculate the closed-shell molecule.
・ Doublet radical is computed by anionize the SAC wavefunction.
This electron-attached state is computed by SAC-CI method.
・ These four approaches are numerically equivalent.
Geometry optimizations of [(N3)2Fe(NO)2]Direct SAC-CI SD-R / LANL2DZ ECP on Fe,
aug-cc-pVDZ on N, O.
v.s. “Broken-Symmetry” TPSSh/def2-TZVP
[(N3)2Fe(NO)2]Symmetry
Fe-N1
Fe-N1A
Fe-N2
Fe-N2A
N1-O1
N1A-O1A
N2-N3
N3-N4
O1-N1-Fe
Fe-N2-N3
N4-N3-N2
Exptl.[2]
C2
1.693
1.693
1.948
1.948
1.172
1.172
1.160
1.067
160.7
141.9
174.3
TPSSh
SAC-CI (A)
C1
1.728
1.728
1.976
1.977
1.180
1.180
1.200
1.156
164.3
129.4
176.2
C2
1.660
1.660
1.974
1.974
1.164
1.164
1.170
1.088
161.0
141.9
174.5
[2]
Tsai, M.-L.; Hsieh, C.-H.; Liaw, W.-F.
Inorg. Chem. 2007, 46, 5110-5117.
Charge and spin analyses of [(N3)2Fe(NO)2]Direct SAC-CI SD-R / LANL2DZ ECP on Fe,
aug-cc-pVDZ on N, O.
v.s. “Broken-Symmetry” TPSSh/def2-TZVP
TPSSh/def2-TZVP
Charge
Fe1
0.420
N1
0.076
O1
-0.281
N1 + O1
-0.204
N1A
0.077
O1A
-0.281
N1A + O1A
-0.204
N2
-0.463
N3
0.337
N4
-0.380
N2 + N3 + N4
-0.506
N2A
-0.464
N3A
0.338
N4A
-0.380
N2A + N3A + N4A -0.506
Spin Density (e )
2.902
-0.636
-0.455
-1.091
-0.636
-0.455
-1.091
0.021
-0.019
0.138
0.140
0.021
-0.019
0.137
0.140
SAC-CI
Charge
0.962
0.258
-0.467
-0.209
0.258
-0.467
-0.209
-0.573
0.309
-0.507
-0.772
-0.573
0.309
-0.507
-0.772
Spin Density (e )
0.000
0.009
0.007
0.016
0.009
0.007
0.016
0.005
-0.001
0.002
0.007
0.005
-0.001
0.002
0.007
Geometry optimizations of [(I)2Fe(NO)2]Direct SAC-CI SD-R / LANL2DZ ECP on Fe,
aug-cc-pVDZ on N, O.
v.s. “Broken-Symmetry” TPSSh/def2-TZVP
[(I)2Fe(NO)2]Symmetry
Fe-N1
Fe-N2
Fe-I1
Fe-I2
N1-O1
N2-O2
Fe-N1-O1
Fe-N2-O2
[3]
Exptl.[3]
C1
1.679
1.683
2.584
2.596
1.141
1.149
167.7
164.1
TPSSh
SAC-CI (A1)
C1
1.702
1.710
2.646
2.649
1.173
1.175
171.188
163.352
C 2v
1.643
1.643
2.649
2.649
1.145
1.145
167.6
167.6
Bryar, T.R.; Eaton, D.R. Can. J. Chem. 1992, 70, 1917-1926.
Charge and spin analyses of [(I)2Fe(NO)2]Direct SAC-CI SD-R / LANL2DZ ECP on Fe,
aug-cc-pVDZ on N, O.
v.s. “Broken-Symmetry” TPSSh/def2-TZVP
TPSSh/def2-TZVP
Fe
N1
O1
N1 + O1
N2
O2
N2 + O2
I1
I2
Charge
0.071
0.093
-0.192
-0.099
0.080
-0.197
-0.117
-0.431
-0.424
Spin Density (e )
2.711
-0.546
-0.410
-0.956
-0.566
-0.422
-0.987
0.118
0.115
SAC-CI
Charge
0.267
0.378
-0.462
-0.084
0.378
-0.462
-0.084
-0.549
-0.549
Spin Density (e )
0.000
0.006
0.004
0.010
0.006
0.004
0.010
0.000
0.000
DFT: Comparison among different functionals
and relativistic effects of [(I)2Fe(NO)2]-
[(I)2Fe(NO)2]Symmetry
Fe-N1
Fe-N2
Fe-I1
Fe-I2
N1-O1
N2-O2
Fe-N1-O1
Fe-N2-O2
[(I)2Fe(NO)2]Symmetry
Fe-N1
Fe-N2
Fe-I1
Fe-I2
N1-O1
N2-O2
Fe-N1-O1
Fe-N2-O2
Exptl.[3]
C1
1.679
1.683
2.584
2.596
1.141
1.149
167.7
164.1
Exptl.[3]
C1
1.679
1.683
2.584
2.596
1.141
1.149
167.7
164.1
BP86/TZVP
BP86/TZVP ZORA
C1
1.664
1.664
2.640
2.639
1.186
1.186
165.256
165.005
C1
1.654
1.654
2.625
2.624
1.188
1.188
165.8
165.6
BP86/TZVP DKH BP86/aug-cc-pVTZ ZORA
C1
1.646
1.646
2.620
2.619
1.187
1.187
169.6
169.4
B3LYP/aug-cc-pVTZ ZORA B3LYP/aug-cc-pVTZ DKH TPSSH/def2-TZVP
C1
1.741
1.754
2.675
2.674
1.174
1.179
171.8
159.4
C1
1.535
1.539
2.550
2.530
1.153
1.155
165.5
162.2
C1
1.702
1.710
2.649
2.646
1.173
1.175
171.188
163.352
C1
1.648
1.648
2.625
2.623
1.185
1.185
165.8
166.0
Vibration frequencies of linear NO radicals
Compound
[(NO)2Fe(NO)2]
[(N3)2Fe(NO)2]
-
-
NO frequency (cm-1)
TPSSh/def2-TZVP
1782, 1712
1751, 1691*
1755, 1698
1783, 1741
1775, 1719
1817, 1774
[(I)2Fe(NO)2]
*Initial geometry is obtained from SAC-CI, and the frequencies
are calculated by B3LYP. (Scaling factor 0.89 )
Tsai, M.-L.; Hsieh, C.-H.; Liaw, W.-F.
Inorg. Chem. 2007, 46, 5110-5117.
UV absorptions v.s SAC-CI excitation energies
Direct SAC-CI
-
[(NO)2Fe(NO)2]
Transition
A' → A'
A' → A'
A' → A''
-
[(N3)2Fe(NO)2]
Transition
A→B
A→B
-
-
[(I)2Fe(NO)2]
Transition
A1 → B1
A1 → B2
SAC-CI SD-R
∆E(eV) Wavelength(nm) Oscillator
strength(f )
2.859
453
0.010
3.407
380
0.006
1.757
729
0.015
UV
Exptl.(nm)
SAC-CI SD-R
∆E(eV) Wavelength(nm) Oscillator
strength(f )
3.192
388
0.003
2.205
562
0.012
-
UV
Exptl.(nm) [2]
SAC-CI SD-R
∆E(eV) Wavelength(nm) Oscillator
strength(f )
2.362
525
0.013
3.128
396
0.004
UV
Exptl.(nm)
473
385
744
397
502
701
[2]
Tsai, M.-L.; Hsieh, C.-H.; Liaw, W.-F.
Inorg. Chem. 2007, 46, 5110-5117.
DFT orbitals among three DNICs
( TPSSh/def2-TZVP )
[(NO)2Fe(NO)2]-
[(N3)2Fe(NO)2]-
[(I)2Fe(NO)2]-
Canonical orbitals among three DNIC systems
(SAC-CI)
[(NO)2Fe(NO)2]-
[(N3)2Fe(NO)2]-
[(I)2Fe(NO)2]-
Energy Gaps among Anionic States
anionic EA state
[(NO)2Fe(NO)2][(N3)2Fe(NO)2](L)2Fe(NO)2 [(I)2Fe(NO)2]-
1st state
1st A'
5th A
3rd A1
2nd state
2nd A'
3rd A
2nd A1
3rd state
4th state
1st A
1st A1
2nd A
-
neutral state anionic EA state
SAC Energy SAC-CI Energy
1st state
2nd state
3rd state
4th state
-640.663096
-640.635223
-
-
-708.948369
-708.898150
-708.853320 -708.763387
-971.538079
-971.455814
-971.338311
-
1st state
2nd state
3rd state
4th state
0.0
0.0
0.0
0.8
1.4
2.2
2.6
5.4
5.0
-
-640.564298
-708.753385
-971.328430
[(NO)2Fe(NO)2][(N3)2Fe(NO)2][(I)2Fe(NO)2]-
anionic states
neutral state ∆E (eV)
-2.7
-5.3
-5.7
[(NO)2Fe(NO)2][(N3)2Fe(NO)2][(I)2Fe(NO)2]-
Concluding Remark
• SAC-CI method is very useful and precise to
study the multiconfiguration Fe(NO)4- anion, and
in fact it is the only successful theory up to now
that can describe this system correctly.
Zong-Sian Lin, Tzung-Wen Chiou, Kuan-Yu Liu, Chang-Chih Hsieh,
Jen-Shiang K. Yu*, and Wen-Feng Liaw*,
A Dinitrosyliron Complex within the Homoleptic Fe(NO)4 Anion:
NO as Nitroxyl and Nitrosyl Ligands within a Single Structure,
Inorg. Chem., 51, 10092-10094 (2012).
• Vibrational analysis for the
N-O vibration is planned to
use the ezPES.
Kuan-Yu Liu
劉冠佑
Acknowledgements
• National Science Council
• ATU Plan, Minister of Education
• National Chiao Tung University, Taiwan
Thank you for your attentions.
UV absorption of [(NO)2Fe(NO)2]-
[(NO)2Fe(NO)2]
Transition
A' → A'
A' → A'
A' → A''
A'
A''
SAC-CI SD-R
∆E(eV) Wavelength(nm) Oscillator
strength(f )
2.859
453
0.010
3.407
380
0.006
1.757
729
0.015
1
2
3
4
5
6
7
1
2
3
4
5
6
7
UV
Exptl.(nm)
473
385
744
Excitation Energy
nm
Osc. Strength
Excitation from this state.
0.8065
1604
0.0015
2.8566
453
0.0102
3.2113
403
0.0063
3.4049
380
0.0065
-1.7717
-730
0.0030
4.9708
260
0.0007
0.2812
4601
0.0000
0.9718
1331
0.0395
2.988
433
0.0058
1.4481
893
0.0066
1.7737
729
0.0146
4.7409
273
0.0006
5.8203
222
0.0000
Double excitation
1
4
0
0
0
4
0
1
1
0
3
1
0
0
Exptl.
473
385
744
UV absorption of [(N3)2Fe(NO)2]-
[(N3)2Fe(NO)2]
Transition
A→B
A→B
A
B
SAC-CI SD-R
∆E(eV) Wavelength(nm) Oscillator
strength(f )
3.192
388
0.003
2.205
562
0.012
1
2
3
4
5
6
7
1
2
3
4
5
6
7
UV
Exptl.(nm)
397
502
701
Excitation Energy
nm
Osc. Strength
2.5783
481
0
5.0109
247
0.0032
1.3644
909
0.0001
5.7847
214
0.0011
Excitation from this state.
7.011
177
0.0004
7.3249
169
0.0046
3.1919
388
0.0033
2.2048
562
0.0124
5.4551
227
0.0027
5.4754
226
0.0169
6.9979
177
0.0036
7.4919
165
0.0136
8.029
154
0.035
Double excitation
1
4
4
2
4
2
3
1
2
2
1
1
3
1
Exptl.
397
502
UV absorption of [(I)2Fe(NO)2]-
SAC-CI SD-R
∆E(eV) Wavelength(nm) Oscillator
strength(f )
2.362
525
0.013
3.128
396
0.004
[(I)2Fe(NO)2]
Transition
A1 → B1
A1 → B2
A1
A2
B1
B2
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
UV
Exptl.(nm)
-
Excitation Energy
nm
Osc. Strength (f )
5.307
234
0.0001
2.1735
570
0.0012
Excitation from this state
6.061
205
0.0083
7.1264
174
0.0072
2.9194
425
0.0000
7.7967
159
0.0000
8.9584
138
0.0000
11.3277
109
0.0000
13.1297
94
0.0000
2.362
525
0.0128
5.8295
213
0.0037
7.3236
169
0.0097
8.4683
146
0.0144
9.0618
137
0.0019
3.1276
396
0.0038
5.8502
212
0.0003
7.4853
166
0.0002
8.5082
146
0.1119
8.9267
139
0.0049
Double excitation
1
3
7
0
0
1
0
0
0
12
1
0
0
2
16
2
1
1
15
0
Exptl.
-
Enemark−Feltham notation
{Mn(NO)x}n
x = the number of nitrosyls
n = the total number of electrons associate with
metal d and π* (NO) orbitals
L1L2Fe(NO)2
x=2
n = 7 (d7 for FeI) + 2 (two π* e- for NO ) = 9
The notation for DNICs is {Fe(NO)2}9.
J. H. Enemark; R. D. Feltham, Coord. Chem. Rev. 13, 339, (1974).