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#1 2019-03-01 07:19:33

may01dz
Member
Registered: 2018-07-17
Posts: 10

molecular charge in solid-state structure

Hello,
I want to explore the structural properties of the copper-based complex displayed on Figure.1.
figure1.png

Figure.2 shows the solid-state structure of this complex (as in the CIF file): Other than the copper-based complex, of figure. 1, Figure.2 chow additional three water molecules.

figure2.png

The molecule in the first Figure contains 127 electrons, and that of the second figure contains 151 electrons.
My questions are:
1. Whether I used the molecule in the first figure or that of the second one.
2. There is a way to know the molecular charge in solid-state structure (as in CIF file).
Alternatively, changing, at every time, the molecular charge and optimized its geometrical parameters. The closest optimized structure to the experimental one will be taken into consideration.

thank you very much

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#2 2019-03-01 10:59:23

sobereva
Tian Lu (Multiwfn developer)
From: Beijing
Registered: 2017-09-11
Posts: 291
Website

Re: molecular charge in solid-state structure

1 Since your transition metal coordinate is highly rigid, the influence due to the presence of the waters on the coordinate structure can be safely ignored. Therefore, before the calculation you can safely remove the waters.

2 After removing the waters, I suggest performing geometry optimization for all hydrogens while keeping all heavy atoms fixed (because commonly the position of the hydrogens cannot be well determined by X-ray diffraction). Then, using the resulting wavefunction file, you can calculate atomic charges for all atoms in the coordinate as usual.

Tian

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#3 2019-03-01 14:55:34

may01dz
Member
Registered: 2018-07-17
Posts: 10

Re: molecular charge in solid-state structure

My reason for this question is that some sources assign charges to some component of the system, as shown in the figure below.

C2.png

It was assigned a +2 to the di-copper-based complex and -1 to ONO2 moiety. Do I consider this situation?

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#4 2019-03-01 21:11:58

sobereva
Tian Lu (Multiwfn developer)
From: Beijing
Registered: 2017-09-11
Posts: 291
Website

Re: molecular charge in solid-state structure

Please simply ignore these formal charges, they are assigned artificially and do not make great sense. You only need to properly set total net charge in the quantum chemistry calculation, only the finally obtained atomic charges can relatively faithfully represent actual charge distribution.

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#5 2019-03-02 07:24:20

may01dz
Member
Registered: 2018-07-17
Posts: 10

Re: molecular charge in solid-state structure

OK....thank you very much

sobereva wrote:

Please simply ignore these formal charges, they are assigned artificially and do not make great sense. You only need to properly set total net charge in the quantum chemistry calculation, only the finally obtained atomic charges can relatively faithfully represent actual charge distribution.

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