Weekly Report (20150511-20150517)
Ke An
Work summary:
For the past week, I mainly focused on the aromaticity of metallabenzenes.
At first, according to the ASE values computed by Frenking, I chose the most and the least four
aromatic metallabenzenes to investigate the ACID plots. Below are the  and  ACID plots and the
key occupied -orbitals of those selected metallabenzenes.
Table 1
metallabenzenes
ASE
(kcal/mol)
-orbitals
[M] = PtCp
37.6
36,
38,
39, 43, 44
[M] = IrCl2(PH3)2
[M] = RhCl2(PH3)2
[M] = PdCp
[M] = Pt(PH3)2
[M] = Pd(PH3)3
[M] = Pd(PH3)2
[M]
= Ir(NCMe)2(PH3)2
33.5
33.4
32.8
13.0
12.6
11.8
8.7
29,
32,
33, 37, 40
28,
32,
33, 36, 39
35,
38,
39, 42, 44
27,
28,
31, 34
31,
33,
36, 38
27,
28,
31, 34
47,
50,
52, 53, 55
NICS(0)
NICS(0)zz
NICS(1)zz

-14.1
-14.9
-12.5

total
11.0
19.2
-0.6
-3.1
4.2
-13.1

-8.4
-6.6
-5.1

total
10.2
17.0
-2.1
-1.8
10.4
-7.2

-6.2
-6.2
-4.6

total
7.8
14.2
-3.2
1.6
8.0
-7.8

-14.5
-10.5
-8.6

total
12.3
15.4
-2.4
-2.2
4.9
-11.0

-4.1
16.8
14.3

total
12.0
16.8
-1.2
7.9
33.6
13.1

-8.4
-2.8
-2.0

total
7.9
9.6
-6.3
-0.5
6.8
-8.3

-4.3
17.2
14.7

total
11.0
10.9
-4.7
6.7
28.0
10.0

-1.5
-8.5
2.0

total
4.4
23.9
-5.0
2.9
15.4
-3.0
-systems
-systems
Figure 1. ACID plots (isovalue = 0.035) of the most and the least aromatic metallabenzene in
Frenking’s paper.
From Figure 1 we can see that metallabenzenes with higher ASE values have stronger diatropic ring
current. The Cp ligand can affect the  aromaticity of the 6MR to make it show stronger 
aromaticity. Metallabenzenes with lower ASE values show disordered ring current in  system but
clear diatropic ring current in  system.
In addition, I selected four metallabenzens containing Ru, Os, Rh, and Ir fragments (see Figure 2),
and tried to compare the ACID plots between the metallabenzenes and the corresponding complexes
with fused three-membered rings. However, when optimized the fused structures containing Rh and
Ir fragments, the 3MRs are always broken. So I only showed the AICD plots of the other two
complexes. As we can see in Figure 2, when fused with 3MRs, the 6MR are still  aromatic.
metallabenzenes
ASE
(kcal/mol)
18.6
21.2
33.4
33.5
-orbitals
28, 38, 39,
40
30, 35, 38,
40
30, 38, 39,
40
31, 35, 39,
40
NICS(0)
NICS(0)zz
NICS(1)zz

-1.8
1.9
0.5

total
2.0
-2.3
-15.6
0.3
-0.4
-15.1

-13.7
-11.0
-8.9

total
13.5
13.7
-4.7
-0.2
2.7
-13.6

-1.0
-1.2
-2.4

total
4.2
-2.8
-14.0
3.3
-4.0
-16.3

-12.8
-15.5
-13.0

total
11.0
16.7
-2.7
-1.8
1.2
-15.8
-systems
-systems
Figure 2. ACID plots (isovalue = 0.035) for ruthenabenzene, osmabenzene, and structures with
fused 3MR containing Ru and Os fragments.
I have tried to apply the structures ([Os] = OsCl2(PH3)2, [Ru] = RuCl2(PH3)2) optimized by Frenking
to calculate the CMO-NICS and ACID plots, but the wave-function are instable.