Molecular structure of 5,10,15,20-tetrakis(4′-fluorophenyl)porphyrin by combined gas-phase electron diffraction/mass spectrometry experiment and DFT calculations

Article abstract of DOI:10.1016/j.molstruc.2020.128662

Molecular parameters of 5,10,15,20-tetrakis(4′-fluorophenyl)porphyrin were determined for the first time by gas-phase electron diffraction. Conformational preference was investigated based on the experimental data and was found to be in the good agreement

Full text of DOI:10.1016/j.molstruc.2020.128662

Journal Pre-proof
Molecular structure of 5,10,15,20-tetrakis(4′-fluorophenyl)porphyrin by combined gas-
phase electron diffraction/mass spectrometry experiment and DFT calculations
Ivan Yu Kurochkin, Alexander E. Pogonin, Arseniy A. Otlyotov, Aleksey N. Kiselev,
Alexander V. Krasnov, Sergey A. Shlykov, Georgiy V. Girichev
PII:
S0022-2860(20)30987-X
DOI:
https://doi.org/10.1016/j.molstruc.2020.128662
MOLSTR 128662
Reference:
To appear in: Journal of Molecular Structure
Received Date: 19 March 2020
Revised Date: 31 May 2020
Accepted Date: 9 June 2020
Please cite this article as: I.Y. Kurochkin, A.E. Pogonin, A.A. Otlyotov, A.N. Kiselev, A.V. Krasnov,
S.A. Shlykov, G.V. Girichev, Molecular structure of 5,10,15,20-tetrakis(4′-fluorophenyl)porphyrin by
combined gas-phase electron diffraction/mass spectrometry experiment and DFT calculations, Journal
of Molecular Structure (2020), doi: https://doi.org/10.1016/j.molstruc.2020.128662.
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Ivan Yu. Kurochkin: Data curation, Formal analysis, Investigation, Visualization, Writing - original draft,
Writing - review & editing.
Alexander E. Pogonin: Conceptualization, Data curation, Formal analysis, Investigation, Validation,
Writing - original draft, Writing - review & editing, Project administration, Funding acquisition.
Arseniy A. Otlyotov: Data curation, Formal analysis, Investigation, Validation, Writing - original draft,
Writing - review & editing.
Aleksey N. Kiselev: Investigation, Conceptualization.
Alexander V. Krasnov: Investigation.
Sergey A. Shlykov: Investigation, Writing - review & editing.
Georgiy V. Girichev: Conceptualization, Investigation, Methodology, Resources, Supervision, Writing -
review & editing, Project administration, Funding acquisition.

Molecular structure of 5,10,15,20-tetrakis(4’-fluorophenyl)porphyrin by combined gas-phase
electron diffraction/mass spectrometry experiment and DFT calculations
a
a
a
a,b
Ivan Yu. Kurochkin, Alexander E. Pogonin, * Arseniy A. Otlyotov, Aleksey N. Kiselev,
a
a
a
Alexander V. Krasnov, Sergey A. Shlykov, Georgiy V. Girichev, *
a
Ivanovo State University of Chemistry and Technology, Sheremetevskiy av. 7, 153000,
Ivanovo, Russian Federation
b
G.A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences,
Akademicheskaja str., 1, 153045, Ivanovo, Russian Federation
*
corresponding authors: pogonin@isuct.ru, girichev@isuct.ru
Graphical abstract
Highlights
First experimental study of H P-4C H F molecular structure in gas phase was performed.
2
6
4
The sublimation enthalpy of H P-4C H F were obtained.
2
6
4
Conformational analysis of H P-4C H F using DFT calculations and GED was carried out.
2
6
4
Assignment of vibrational spectrum of H P-4C H F was performed.
2
6
4
Abstract
Molecular parameters of 5,10,15,20-tetrakis(4’-fluorophenyl)porphyrin were determined for the
first time by gas-phase electron diffraction. Conformational preference was investigated based
on the experimental data and was found to be in the good agreement with the preliminary model-

based considerations. The experimental vibrational spectrum was measured and assigned. The
structural features were compared with that of the previously studied Zn(II) and Pd(II)
complexes with tetraphenylporphyrin. The results of the Knudsen effusion mass spectrometry
-1
experiment yielded the value of the sublimation enthalpy of ∆ H°(584 К) = 233(4) kJ mol .
sub
The introduction of substituents into the para-position of phenyl fragments does not significantly
affect the electron density distribution and geometry of the coordination cavity.
Keywords: gas-phase electron diffraction; mass spectrometry; porphyrin; conformation;
molecular structure
Introduction
Porphyrins and their derivatives represent a widely discussed class of macrocyclic compounds
due to the diversity of their properties: biological activity, conductive and photoconductive
properties. On their basis, various catalysts, chemical sensors, drugs, photovoltaic devices, and
organic semiconductor devices have already been created [1–4]. Nevertheless, interest remains in
the studies of these compounds in order to create new and improve existing materials based on
them. The formation of thin porphyrin films with needed structure is usually performed by
physical vapor deposition (PVD) technology. Therefore, the information about the vaporization
processes, thermodynamic functions and structural data are indeed necessary for the compounds
belonging to this class.
Halogen-substituted porphyrins are used primarily as precursors in the functionalization of the
porphyrin core and the synthesis of various dyads, triads, oligomers, polymers, dendrimer
structures [5,6]. In connection with the prospects of using porphyrin derivatives in the creation of
chemical sensors and semiconductor materials, studies of vaporization processes and the
composition of the gas phase of these compounds are relevant. The studies of the vaporization
processes have been the subject of many investigations. The most informative among them
regarding the composition of the gas phase are mass spectrometric studies. The authors [7] made
a series of investigations devoted to the study of the thermodynamics of vaporization for the
large number of porphyrin derivatives. For 5,10,15,20-tetrakis(4’-halogenophenyl)porphyrins
H P-4C H X (X = F, Cl, Br), the sublimation enthalpies were obtained by inert gas flow method
2
6
4
-1
-1
-1
and the corresponding values are 178 ± 4 kJ mol , 311 ± 5 kJmol , 135 ± 4 kJ mol ,
respectively. Such a drastic change for H P-4C H Cl was explained by the authors of [7] to be
2
6
4
possibly caused by peculiarities of its crystal structure. Interactions between chlorine atoms of
adjacent molecules lead to the significant increase in sublimation enthalpies of H P-4C H Cl as
2
6
4
-1
compared with 240 ± 7 kJ mol for unsubstituted tetraphenylporphyrin (H P-4C H ) [7].
2
6
5
However, the authors [8] report large discrepancies in the obtained values as compared to
-1
different studies, e.g., the value of ∆ H°(T) for H P-4C H varies from 110 to 370 kJ mol
sub
2
6
5
according to different works.
Even less attention has been paid to the structures of the individual molecules of the halogen-
substituted porphyrins in the gas phase. Gas-phase electron diffraction (GED) is almost the only
accessible experimental method for determination of their molecular structures. However, the
study of a porphyrin molecule by GED method is often a non-trivial task. This is not only due to
the large number of atoms in a molecule, but by conformer and isomer diversity. Up to now,
only the structures of tin (II) octamethylporphyrin [9], copper and zinc etioporphyrins [10,11],

zinc and palladium tetraphenylporphyrins (ZnTPP and PdTPP) [12], and several porphyrin-
related compounds [13–15] have been reported.
Earlier in our laboratory, a series of studies were carried out to establish the sensitivity of GED
method with respect to determination of the conformational composition of macrocyclic
molecules with different substituents [10,11]. A separate model comparison was performed for
H P-4C H X (X = F, Br) molecules and the results are described in [16]. The model radial
2
6
4
distributions of the different conformers were calculated and compared to each other. Based on
such a comparison, it was concluded that reliable experimental determination of the distances
between chemically bonded atoms is possible, while the refinement of the position of halogen-
phenyl substituents relative to the macrocyclic backbone of the molecule is at the limit of the
possibilities of GED method.
In the present contribution we report the results of the experimental GED study of H P-4C H F
2
6
4
(Fig. 1) aiming to complement the model-based predictions.
Fig. 1. Numbering/labeling scheme for H P-4C H F.
2
6
4
Experimental details
Synthesis of H P-4C H F
2
6
4
H P-4C H F was synthesized by condensation of fluorine-substituted benzaldehyde with pyrrole
2
6
4
in boiling xylene in the presence of trifluoroacetic acid as a catalyst and using atmospheric
oxygen as an oxidizing agent for porphyrinogen. The synthesis is described elsewhere in the
literature [17–19] and some details can be found in the Supplementary Information.

Knudsen effusion mass-spectrometry experiment
Due to large discrepancies in the obtained values of sublimation enthalpy for
tetraphenylporphyrins [8], a mass spectrometric study of H P-4C H F was carried out in current
2
6
4
work.
The sublimation of H P-4C H F was investigated by Knudsen method with use of MI1201
2
6
4
commercial magnetic sector mass spectrometer adapted to thermodynamic studies and described
in details in Ref. [20]. A sample of H P-4C H F was evaporated from a molybdenum effusion
2
6
4
cell. The ratio of the cross-sectional square of the cell to the square of the effusion orifice was
about 1000, which made it possible to practically eliminate the violation of thermodynamic
equilibrium due to the efflux of vapors from the effusion orifice in the experiments performed.
Ion currents were measured in the temperature range of 550-618 K. The temperature of the cell
was measured by a tungsten-rhenium thermocouple W-Re 5/20. The energy of ionizing electrons
of 45 eV. The temperature dependences ln(IT) = f(1000/T) of ion currents for parent ion [H P-
2
+
4
C H F] were well approximated by straight lines (Fig. S1). The overall results of mass
6
4
spectrometry (MS) experiment indicate the thermal stability of H P-4C H F at least below 618
2
6
4
K that opens a possibility for a GED experiment under similar conditions.
Gas-phase electron diffraction/mass-spectrometry experiment
The diffraction patterns of H P-4C H F were obtained by synchronous GED and MS
2
6
4
experiment carried out using the EMR-100/APDM-1 unit [21–23]. A sample of H P-4C H F
2
6
4
was evaporated from a molybdenum effusion cell with a cylindrical effusion nozzle of 0.6 × 1.6
mm size (diameter × length). The ratio of the evaporation area to the effusion orifice area was
above 400. The conditions of the GED/MS experiments are listed in Table 1. Accurate
wavelengths of electrons were calibrated using polycrystalline zinc oxide.
Table 1. Conditions of the GED/MS experiments.
Nozzle-to-plate distance, mm
Number of recorded films
Primary electron beam current, ꢀA
Wavelength of electrons, Å
Temperature of effusion cell, K
Exposure time, s
338
6
598
5
1.14
0.88
0.04086(3) 0.04142(4)
688(13)
100
677(8)
60
Residual gas pressure, Torr
–
–
6
7
-6
-
in the diffraction chamber
in mass-spectrometric block
1.4·10
7.9·10
1.3·10
–7
-
6.0·10
-1
Scattering angles range/ ∆s, Å
3.3-28.9/0.1 1.7-16.2/0.1
50(1) 50(1)
Ionization voltage, V
The optical densities of the diffraction patterns were measured by a modified MD-100 (Carl
Zeiss, Jena) microdensitometer [24] with a step size of 0.1 mm along diagonal. A 10 × 130 mm
region was scanned; the number of equidistant scan lines was 33.

Mass spectra of the H P-4C H F vapor effusing into the gas electron diffractometer were
2
6
4
recorded simultaneously throughout each of the GED experiments. No volatile admixtures were
detected.
Refinement of the GED data
Structural analysis of the GED data was carried out using the UNEX program [25].
Molecular models of H P-4C H F conformers possessing C , C (two models), and D2
2
6
4
2v
2h
symmetries (Fig. 2) were described in a similar way (the detailed description of Z-matrices can
be found in Supplementary Information and the refinements were performed under
corresponding symmetry constraints. Starting values of the molecular parameters were taken as
those optimized at B3LYP/pVTZ [26–30] level and then used as flexible restraints.
Regularization factor α was adjusted manually in order to obtain a stabilized solution.
Contributions of GED data into refined parameters were calculated according to W2 method
described in [31] and the values are given in Supplementary Information. In the least-squares
analyses, the structural disagreement factors between experimental and theoretical molecular
intensities were calculated as
ꢓ
∑ꢅꢃꢄ ꢆ ꢊꢄ ꢋ − ꢌ ꢄ ꢆ
ꢊꢄ ꢋꢒ
ꢅ
ꢅ
ꢇꢈꢉ
ꢅ
ꢍ ꢅ ꢎꢏꢇꢐꢑ
ꢂ
(1)
ꢀꢁ
=
∙ 100%
∑ꢅꢔꢄ ꢆ
ꢊꢄ ꢋꢕꢓ
ꢅ
ꢎꢏꢇꢐꢑ
ꢅ
where ꢄ ꢆ ꢊꢄ ꢋ is experimental molecular scattering intensity, ꢌ is the scale, ꢄ ꢆ
ꢊꢄ ꢋ is
ꢅ
ꢖꢗꢘ
ꢅ
ꢍ
ꢅ
ꢎꢏꢇꢐꢑ
ꢅ
theoretical molecular scattering intensity.
Amplitudes of vibrations and vibrational corrections (r – r ) for all conformers were computed
h1
a
from the harmonic force field obtained at B3LYP/pVTZ level with use of VibModule program
32]. In order to increase the quality of the background lines the leveled experimental total
[
intensity functions were used as suggested in [33].
Computational details of structure optimization and IR spectra modeling
Quantum chemical calculations were performed for a single molecule in a gas phase with use of
Gaussian 03 program package [34]. B3LYP functional [35,36] pVTZ [26–30] basis sets ware
used. The pVTZ [26–30] basis set (for H, C, N, F) was taken from the EMSL library [30]
(denoted as «GAMESS pVTZ»). The tight optimization (opt=tight) and the ultrafine integral grid
with 99 radial shells and 590 angular points per shell were used. In order to adequately analyze
the changes in the molecular structures within the series under consideration, H P-4C H ,
2
6
5
ZnTPP and PdTPP were calculated at the same level of theory as H P-4C H F: pVTZ [26–30]
2
6
4
–
–
for H, C, N, cc-pVTZ [37] – for Zn, cc-pVTZ-PP and Stuttgart-Koeln MCDHF RSC ECP [38]
for Pd.
The theoretical IR spectrum was calculated in the harmonic approximation at the same level of
theory. A vibrational assignment corresponding to irreducible vibrational representation
Γ=59A +56A +56B +57B has been carried out for H P-4C H F (model of C symmetry). The
1
2
1
2
2
6
4
2v
-1
-1
normal modes of more than 2 km·mol intensity in the range of 500-3700 cm were assigned to
the symmetry and to the internal coordinates giving the main contribution (Table S1).It is worth
noting some differences in the shape of the model spectra for the gas phase and experimental
spectra for the solid phase (Fig. S2) caused by the influence of the environment in the crystal.
Correlation between the bands in model and experimental spectra for H P-4C H F is close to
2
6
4
linear (correlation factor – 0.99995, Fig. S3). The obtained scaling coefficient (0.956, Fig. S3) is

in good agreement with expected value 0.965 [39,40] for the level of theory B3LYP/TZVP. It
should be noted, experimental spectrum of H P-4C H F measured in this work is in good
2
6
4
agreement with literature data [41,42].
Results and discussion
Sublimation enthalpy of H P-4C H F
2
6
4
+
According to the recorded mass spectra, the parent molecular ion [H P-4C H F] dominates over
2
6
4
the fragment ions occurring during dissociative ionization process (Table 2). Only the peaks of
+
2+
several other ions ([H P-3C H F] and [H P-4C H F] ) exceed a 5% intensity level as
2
6
4
2
6
4
compared to the parent ion as is generally observed for the porphyrins at the ionizing voltage of
5 V. The set of ions observed in mass-spectra confirms the thermal stability of H P-4C H F, at
4
2
6
4
least below 618 K, and it is also in the qualitative agreement with that observed in the GED/MS
experiment.
Table 2. Electron ionization mass spectrum of saturated vapors over H P-4C H F recorded
2
6
4
during experiments
+
I , calculated relative to parent ion [H P-4C H F]
rel
2
6
4
m/z,
a.m.u.
MS
(GED/MS)
1
(GED/MS)
L2=598 мм
Ions
(Knudsen) L =338 мм
+
[
[
[
H P-4C H F]
686
591
343
100
6
10
45
5
100
27
40
50
0.04
688
100
35
50
50
0.04
677
2
6
4
+
H P-3C H F]
2
6
4
2+
H P-4C H F]
2
6
4
U , V
ion
Conditions
U , kV
acc
T, K
618
+
The plot of ln(I·T) = f(1000/T) for [H P-4C H F] ions is shown on Fig. S1. In each case,
2
6
4
the set of the points resulted from the measurements with a step-by-step increase in temperature,
and then with a step-by-step decrease. Each point of the plot corresponds to the ion current
measured after its stabilization at a given temperature. No hysteresis at the temperature increase
and decrease was observed that confirms the points on the plot to correspond to the equilibrium
states inside effusion cell. The dependence ln(I·T) = f(1000/T) was found to be closely
approximated by a straight line (coefficient of correlation r =0.99978), that also indicates
corr
thermal stability of the sample. The enthalpy of sublimation of H P-4C H F was calculated by
2
6
4
linear regression using Clausius-Clapeyron equation and resulted in the value of ∆ H°(584 К) =
sub
-1
2
33±4 kJ mol . This result differs from the previously published [7] value of 178±4 kJ/mol.
Possible reason for the difference observed is an insufficient saturation of the vapor in
experiments [7].
Molecular structure by GED and calculations

H P-4C H F possesses a quasi-planar structure of the macrocycle. Deviation from planarity can
2
6
4
be explained by the influence of p-fluorophenyl groups attached to the meso-positions of the
porphyrin core. The location of the -C H F groups in the macrocycle plane is energetically
6
4
unfavorable due to induced steric repulsions: the relative energy of conformer VI (Fig. 2) is as
-1
large as 767 kJ mol [16]. Moreover, the perpendicular arrangement of the -C H F groups is
6
4
also unfavorable: the conformation V corresponds to the saddle point on the PES with a relative
-1
energy of 1 kJ mol [16]. A similar effect was reported for PdTPP and ZnTPP [12]
macrocycles. The deviation of the torsion angle C -C -C -C from 90 º was explained by energy
α1
m
1
2
balance between orbital conjugation of the phenyl rings and the porphyrin framework on the one
hand and low steric repulsion of the phenyl groups and pyrrole rings on the other hand [12].
According to our preliminary DFT-based study [16], H P-4C H F exhibits 4 conformers (Fig. 2)
2
6
4
with relatively low relative energies (Table 3). All these structures were individually examined
against the experimental GED data. According to the results of the GED refinements, C model
2
v
of H P-4C H F fits the experimental data better as compared to the other models considered
2
6
4
(Fig. 3 and Fig. 4). R-factors for three other conformers (II-IV) are larger and follow the trend
predicted by preliminary [16] model calculations (Table 3). The refined parameters are in the
good agreement with their calculated analogues (Table 4 and S2). It should be noted that
refinement of the mixture including all the conformers resulted in the extremely large
correlations between three mole fraction parameters that makes such a treatment unreliable.
Fig. 2. Conformer models of H P-4C H F: C -two fold symmetry axis, σ - mirror plane.
2
6
4
2

a,b
Table 3. Relative energies (at B3LYP/pVTZ level), model and structural R -factors
for the
f
considered conformers of H P-4C H F.
2
6
4
Conformer model I
II
III
IV
Symmetry
C2v C2h C2h D2
-1
ꢁ
E, kJ mol [16]
0
0
0.47 0.53 0.94
2.36 2.75 5.08
a
R
f, mod.
b
, % [16]
Rf, str. , %
5.47 5.99 6.17 7.25
a
the disagreement factor Rf, mod. between two theoretical scattering intensities was calculated as
ꢓ
∑ꢅꢃꢄ ꢆ
ꢊꢄ ꢋ
− ꢄ ꢆꢎꢏꢇꢐꢑꢊꢄꢅꢋꢝꢐꢞꢇꢟꢠꢡꢒ
ꢅ
ꢎꢏꢇꢐꢑ ꢅ ꢙꢐꢚꢛ.ꢜ ꢅ
ꢂ
(2)
ꢀꢁ
=
∙ 100%
∑ꢅꢔꢄ ꢆ
ꢊꢄ ꢋ
ꢕꢓ
ꢅ
ꢎꢏꢇꢐꢑ ꢅ ꢙꢐꢚꢛ.ꢜ
where R is disagreement factor, ꢢ ꢤ
ꢊꢢ ꢋ
is theoretical molecular scattering intensity
f
ꢣ
ꢥꢦꢧꢨꢩ ꢣ ꢪꢨꢫꢬ.ꢭ
for conformer I, ꢢ ꢤ
ꢊꢢ ꢋ
is theoretical molecular scattering intensity for conformer j;
the disagreement factor Rf, str. between experimental and theoretical scattering intensities was
ꢣ
ꢥꢦꢧꢨꢩ ꢣ ꢮꢨꢯꢧꢰꢠꢱ
b
calculated by the formula (1).
Fig. 3. Experimental (circles) and theoretical (solid lines) molecular intensities sM(s) for H P-
2
4
C H F and the residuals ꢁsM(s).
6 4

Fig. 4. Experimental (circles) and theoretical (solid line) radial distribution functions f(r) for
H P-4C H F and residual curves ꢁf(r).
2
6
4
A special question is the reliability of the determination of positions of the fluorophenyl groups
relative to the porphyrin core. In spite of the low uncertainty for the torsion angle χ(C -C –C -
α2
m
1
C ) from the least-squares, the real value of uncertainty should be much larger as can be
2
estimated from the R vs. χ(C -C –C -C ) plot using the Hamilton statistical criterion at 0.05
f
α2
m
1
2
significance level. (Fig. 5). Another evidence of the torsional flexibility of H P-4C H F stems
2
6
4
from the results of calculations. A relaxed PES scan performed at B3LYP/pVTZ level in the
range of 20 º – 160 º with 10 º increments yielded a shallow minimum within the range 60 º –
1
20 º, being in the good qualitative agreement with that from R vs. τ(C -C –C -C ) dependence
f α2 m 1 2
(Fig.6). With a further (τ < 60 º or τ > 120 º) deviation (Fig. 6) from the perpendicular
arrangement of the fluorophenyl rings, a significant increase in energy occurs. The coplanar
location of the p-fluorophenyl rings (with χ(C -C -C -C ) = 0 º (180 º)) is unfavorable
α
m
1
2
-1
energetically (relative energy of conformation VI is 767 kJ mol [16]) and leads to significant
out-of-plane distortions of the macrocycle due to steric repulsions.
No experimental data on the crystalline structure of H P-4C H F are available. However, X-ray
2
6
4
data were published for the similar compounds – H P-4C H Cl and H P-4C H Br. According
2
6
4
2
6
4
to calculations [16] the nature of a halogen does not influence significantly the structure of
porphyrin core. The geometrical parameters of the porphyrin core for these molecules in gas and
crystal phases are in good agreement with each other.

Fig. 5. The ratio of disagreement factors R as a function of torsion angle C -C -C -C , responsible for
f
α2
m
1
2
rotation of –C H F-groups in case of four models (C , 2 variants of C , D ): R – factor of disagreement
6
4
2v
2h
2
f
between experimental and theoretical molecular scattering intensities sM(s); Rthreshold – uncertainty
according to the Hamilton’s statistical criterion [43] at 0.05 significance level
.

35
30
25
20
15
10
5
0
RT GED
48
132
20 30 40 50 60 70 80 90 100 110 120 130 140 150 160
C
-C -C -C , deg.
α2 m 1 2
Fig. 6. Relaxed potential energy function of internal rotation of one p-fluorophenyl group in the
H P-4C H F molecule around the C -C bond. Line RT corresponds to the temperature of GED
2
6
4
m
1
experiment.

a
Table 4. Experimental and theoretical structural parameters of H P-4C H X (X=F, Cl, Br) and metal complexes ZnTPP and PdTPP.
2
6
4
Parameter
H
2
P-4C
6
H
4
F
H
2
P-4C
6
H
4
Cl
H
2
P-4C
6
H
4
Br
ZnTPP
GED rh1
D2d
PdTPP.
GED rh1
D2d
B3LYP
GED rh1
r -r
h1
lexp
lcalc
a
X-ray,
X-ray,
X-ray,
/
pVTZ
C2v
C2v
c
c
c
r
r
r
Rf=5.47%
R 4.29% R =4.56%
f = f
[
44]
[45]
[46]
[
16]
[12]
[12]
b
N -C
N -C
2
1.364
1.374
1.458
1.432
1.351
1.367
1.408
1.401
1.499
1.399
1.392
1.385
1.355
1.011
1.077
1.083
110.7
106.4
106.4
125.4
108.2
105.7
110.7
1.362(5)
0.0038 0.056(2) 0.051 1.367
1.378
1.370
1.436
1.442
1.355
1.348
1.407
1.388
1.492
1.385
1.379
1.365
-
0.999
1.000
1.000
109.7
107.6
107.2
125.3
107.9
106.2
103.2
1.372
1.375
1.444
1.434
1.350
1.358
1.405
1.401
1.497
1.379
1.388
1.392
-
0.880
0.950
0.950
109.7
108.0
107.1
125.6
107.8
106.5
108.6
1
α1
α2
1.377(3)
1.446(3)
1.361(3)
1.407(3)
1.377(3)
1.373(5) 0.0007 0.054(2) 0.049 1.364
1.461(5) -0.001 0.059(2) 0.054 1.447
C -C
α1 β1
1.445(3)
1.358(3)
1.400(3)
C -C
1.437(5) 0.0001 0.057(2) 0.052 1.429
1.352(9) -0.0048 0.049(2) 0.045 1.345
1.370(8) -0.0006 0.051(2) 0.047 1.352
1.410(5) 0.0000 0.055(2) 0.050 1.398
1.402(5) 0.0001 0.055(2) 0.050 1.398
1.499(5) -0.0008 0.061(2) 0.055 1.495
1.403(5) 0.0004 0.054(2) 0.049 1.383
1.394(5) -0.0000 0.053(2) 0.048 1.381
1.387(5) 0.0001 0.053(2) 0.048 1.366
α2 β2
C -C
β1 β1
C -C
β2 β2
C -C
m
α1
C -C
m
α2
C -C1
1.489(8)
1.410(3)
1.403(3)
1.489(8)
1.398(3)
1.392(3)
m
C -C2
1
C -C3
2
C -C4
-
-
-
-
3
C-F
1.355(5) -0.0005 0.054(2) 0.049
-
N -H
1.012(5) 0.0015 0.072(5) 0.071 0.861
1.078(5) 0.0011 0.076(6) 0.076 0.930
1.084(5) 0.0001 0.077(6) 0.076 0.930
111.3(9)
105.4(1.2)
106.1(5)
125.7(5)
108.5(5)
105.2(1.2)
112.3(1.6)
-
1.086(6)
-
-
1.080(6)
-
2
C -H
β
ave
C -H
Ph
ave
N-C -C
110
α1 β1
109.4(3)
109.4(3)
N-C -C
107.1
106.9
125.6
108.0
106.0
109.9
α2 β2
C -C -C
-
-
α1 β1 β1
C -C -C
α2
125.3(8)
-
124.9(14)
-
α1
m
C -C -C
α2 β2 β2
C -N-C
α1
α1
106.6(5)
106.7(4)
C -N-C
α2
α2

-
24
d
8
2( +50)
C -C –C -C
3
72.9
71.2
69.7
62.1
80.3(3.6)
83.3(17.5)
α2
m
1

a
Bond lengths, (r -r ) vibrational corrections and l vibrational amplitudes in Å; bond and torsion
h1
e
angles in degrees.
b
2
2
1/2
Uncertainties given in parentheses were taken for distances as: [(2.5σ ) +σ
] , σ
=
scale
LS
scale
0
.002r, σ is a standard deviation in the least-squares refinement; 3σ for bond angles; 3σ ꢂl
LS LS LS 1
for amplitudes, where l is the amplitude of the first term in the corresponding group.
1
c
Average values calculated in this work using corresponding data
Estimated by Hamilton criterion (Fig. 5).
d
Substitution effect of the F-atom in the para-position of the phenyl group
Substitution of the hydrogen atom by the fluorine one in the para-positions of the phenyl groups
changes the structure of this groups without noticeable distortions of the macroheterocycle: the
bond lengths in the porphyrin core, as well as the perimeter of the coordination cavity (PCC)
change only by 0.001 Å, or less (Table S3). Upon the transition H P-4C H → H P-4C H F, the
2
6
5
2
6
4
bond lengths C -C decrease by 0.008 Å, while the bond angles C -C -C decrease by 1.7 º and
3
4
2
3
4
the C -C -C increases by 2.6 º (Table S3). At the same time, aromaticity in the phenyl ring
3
4
3
increases (NICS (H P-4C H ) = 6.8, NICS (H P-4C H F) = 8.6). The slope of the phenyl rings
2
6
5
2
6
4
varies less by 0.5 º.
The above-mentioned substitution also leads to changes in the IR spectrum (Fig. S2). A
noticeable change in the simulated spectrum is caused by appearance of intense absorption bands
–1
–1
at 1243 cm and 1183 cm , corresponding to vibrations involving F atoms (Table S1). The
–
1
other perceptible changes in the simulated spectra can be found in regions of 1470–1570 cm .
–
Upon the transition H P-4C H → H P-4C H F, the frequencies ω (symmetry A , 1476 cm
2
6
5
2
6
4
180
1
1
–1
)
and ω182 (symmetry B , 1503 cm ) do practically not change, unlike their intensities (13.3 →
2
0
.0 km/mol and 85.1 → 129.7 km/mol). Moreover, the distribution of energy of normal
coordinate vibrations ω182 on internal vibrational coordinates (PED) at the H P-4C H → H P-
2
6
5
2
4
C H F transition changes insignificantly, but in the case of the ω vibration, the contribution
6 4 180
of the coordinates describing the stretching vibrations of C -C increases (~ 10% → ~ 40%) and
β
β
the contribution of the in-plane bending vibrations of CCH decreases (~ 40% → ~ 5%). At H P-
2
4
C H → H P-4C H F, the appearance of the contribution of the CF bond vibrations (~ 6%) to
6 5 2 6 4
-1
the υ185 and ω186 vibrations leads to an increase in the frequency (by 11 and 12 cm ,
respectively) and an increase in the oscillator strength (11.3 → 220.4 km/mol and 20.0 → 303.4
km/mol, respectively).
The effect of a metal atom placed in the center of the coordination cavity
In order to study the effect of placing the metal into the center of the porphyrin core, we
compared the structures of H P-4C H and H P-4C H F with Pd (II) and Zn (II)
2
6
5
2
6
4
tetraphenylporphyrins, studied earlier [12].
Zinc and palladium atoms possess an optimal size to be placed into a porphyrin cavity without
disturbing the planarity of the whole macrocycle, and it does not lead to a significant
rearrangement of the macrocycle structure as confirmed by GED and quantum chemical
calculations (Table 4 and Table S3). Despite relatively low symmetry in the case of H P-
2
4
C H F, caused by the presence of hydrogen atoms in the cavity, the corresponding geometry
6 4
parameters of H P-4C H F, ZnTPP and PdTPP are close to each other. The size of the central
2
6
4
cavity of H P-4C H F (PCC = 22.189 Å) is in between the analogous values for ZnTPP and
2
6
4

PdTPP (22.226 Å and 22.168 Å, respectively). Some differences between H P-4C H F, ZnTPP
2
6
4
and PdTPP molecules can be found in their electronic structure. Introduction of the zinc and
palladium atoms into the cavity leads to an increase in the energy gap between LUMO and
HOMO (ꢁE (H P-4C H F) = 2.73 eV, ꢁE (ZnTPP) = 2.85 eV, ꢁE (PdTPP) = 3.01 eV). It
2
6
4
should also be noted that a slightly larger negative charge is located on the nitrogen atoms in
ZnTPP molecule (q = -0.67) as compared to PdTPP (q = -0.47) and H P-4C H F (q = -0.53
N
N
2
6
4
N
and -0.48) molecules. The differences in charges on the other atoms of the macrocycle for the
three molecules considered do not exceed 0.01.
Conclusions
The experimental molecular parameters of H P-4C H F were obtained for the first time from
2
6
4
gas-phase electron diffraction data. Conformers with different relative orientations of p-
fluorophenyl groups were individually examined against the GED data. The best fit was obtained
with C2v model, while three other considered conformers were determined to possess larger
values of the disagreement factor R . The overall results of the refinements draw a similar
f
qualitative and even quantitative picture as it was described in our earlier work based on the
comparison of the model R-factors. Besides, they are in agreement with the trend of the relative
energies predicted by DFT (B3LYP/pVTZ) calculations. Obviously, the introduction of specific
substituents into the para positions of phenyl fragments does not significantly affect the electron
density distribution and geometric parameters of the coordination cavity, but can significantly
affect the solubility in the corresponding solvents of both the macrocyclic ligand and the metal
complex.
Acknowledgements.
The reported study was funded by Russian Foundation for Basic Research (RFBR) according to
the research project № 18-33-01199. The study of unsubstituted tetraphenylporphyrin and metal
tetraphenylporphyrins was supported by grant of Ministry of Science and Higher Education of
the Russian Federation, grant FZZW-2020-0007. The research was carried out using the
equipment of the Center for collective use at Ivanovo State University of Chemistry and
Technology. The authors are grateful to Ilya A. Tarasyuk and Anna A. Botnar for the IR spectra
measurements.
Supplementary Information.
Supplementary Information to this article is avai1able online at www….. .
Supplementary Information contains synthesis details, data of Knudsen effusion mass-
spectrometry experiment, IR spectra, a vibrational assignment, structural parameters, refined and
calculated geometry structures in Cartesian coordinates, Z-matrices, contributions of GED data
into the refined parameters of C conformer and GED experimental data (average total and
2
v
reduced intensity functions I(s), molecular intensities sM(s) and background lines).

References
[
[
[
[
[
1] H. Mao, H. Deng, H. Li, Y. Shen, Z. Lu, H. Xu, Photosensitization of TiO2
semiconductor with porphyrin, J. Photochem. Photobiol. A Chem. 114 (1998) 209–212.
https://doi.org/10.1016/S1010-6030(97)00260-8.
2] J. Rochford, D. Chu, A. Hagfeldt, E. Galoppini, Tetrachelate porphyrin chromophores for
metal oxide semiconductor sensitization: Effect of the spacer length and anchoring group
position, J. Am. Chem. Soc. 129 (2007) 4655–4665. https://doi.org/10.1021/ja068218u.
3] B.K. Kang, N. Aratani, J.K. Lim, D. Kim, A. Osuka, K.H. Yoo, Length and temperature
dependence of electrical conduction through dithiolated porphyrin arrays, Chem. Phys.
Lett. 412 (2005) 303–306. https://doi.org/10.1016/j.cplett.2005.07.008.
4] M.G. Walter, A.B. Rudine, C.C. Wamser, Porphyrins and phthalocyanines in solar
photovoltaic cells, J. Porphyr. Phthalocyanines. 14 (2010) 759–792.
https://doi.org/10.1142/s1088424610002689.
5] X.-S. Wang, J. Liu, J.M. Bonefont, D.-Q. Yuan, P.K. Thallapally, S. Ma, A porous
covalent porphyrin framework with exceptional uptake capacity of saturated hydrocarbons
for oil spill cleanup, Chem. Commun. 49 (2013) 1533–1535.
https://doi.org/10.1039/C2CC38067F.
[
[
[
[
[
6] L. Li, J. Hollinger, G. Guerin, D.S. Seferos, Synthesis and Network-Like Self-Assembly
of Porphyrin-Polyselenophene Complexes, ChemPhysChem. 13 (2012) 4110–4115.
https://doi.org/10.1002/cphc.201200682.
7] G.L. Perlovich, O.A. Golubchikov, M.E. Klueva, Thermodynamics of porphyrin
sublimation, J. Porphyr. Phthalocyanines. 4 (2000) 699–706.
https://doi.org/10.1002/1099-1409(200012)4:8<699::AID-JPP284>3.0.CO;2-M.
8] L.A. Torres, M. Campos, E. Enríquez, R. Patiño, The enthalpy of sublimation of
5,10,15,20-tetraphenylporphine and 5,10,15,20-tetrakis(4-methoxyphenyl)porphine, J.
Chem. Thermodyn. (2002). https://doi.org/10.1006/jcht.2001.0920.
9] G. V. Girichev, N.I. Giricheva, O.I. Koifman, Y. V. Minenkov, A.E. Pogonin, A.S.
Semeikin, S.A. Shlykov, Molecular structure and bonding in octamethylporphyrin tin(ii),
SnN4C28H28, Dalt. Trans. 41 (2012) 7550–7558. https://doi.org/10.1039/c2dt12499h.
10] N. V. Tverdova, A.E. Pogonin, A.A. Ischenko, V.D. Rumyantseva, O.I. Koifman, N.I.
Giricheva, G. V. Girichev, Combined gas-phase electron diffraction/mass spectrometry
and DFT study of the molecular structure of zinc(II) etioporphyrin-II, Struct. Chem. 26
(2015) 1521–1530. https://doi.org/10.1007/s11224-015-0656-y.
[
[
[
11] A.E. Pogonin, N. V. Tverdova, A.A. Ischenko, V.D. Rumyantseva, O.I. Koifman, N.I.
Giricheva, G. V. Girichev, Conformation analysis of copper(II) etioporphyrin-II by
combined gas electron diffraction/mass-spectrometry methods and DFT calculations, J.
Mol. Struct. 1085 (2015) 276–285. https://doi.org/10.1016/j.molstruc.2014.12.089.
12] G. V. Girichev, N. V. Tverdova, N.I. Giricheva, D.S. Savelyev, V.A. Ol’shevskaya, T.A.
Ageeva, A. V. Zaitsev, O.I. Koifman, Geometric and electronic structures of 5,10,15,20-
tetraphenylporphyrinato Palladium(II) and Zinc(II): Phenomenon of Pd(II) complex, J.
Mol. Struct. 1183 (2019) 137–148. https://doi.org/10.1016/j.molstruc.2019.01.055.
13] N. V. Tverdova, G. V. Girichev, N.I. Giricheva, O.A. Pimenov, Accurate molecular
structure of copper phthalocyanine (CuN8C32H16) determined by gas-phase electron

diffraction and quantum-chemical calculations, Struct. Chem. 22 (2011) 319–325.
https://doi.org/10.1007/s11224-010-9715-6.
[
14] T. Strenalyuk, S. Samdal, H.V. Volden, Molecular Structures of Phthalocyaninatozinc and
Hexadecafluorophthalocyaninatozinc Studied by Gas-Phase Electron Diffraction and
Quantum Chemical Calculations, J. Phys. Chem. A. 111 (2007) 12011–12018.
https://doi.org/10.1021/jp074455n.
[
[
15] A. V. Zakharov, S.A. Shlykov, Y.A. Zhabanov, G. V. Girichev, The structure of
oxotitanium phthalocyanine: a gas-phase electron diffraction and computational study,
Phys. Chem. Chem. Phys. 11 (2009) 3472–3477. https://doi.org/10.1039/b820914f.
16] I.Y. Kurochkin, A.E. Pogonin, A.A. Otlyotov, A.N. Kiselev, G. V. Girichev, DFT study
of molecular structure of 5,10,15,20-tetrakis(4′-halogenophenyl)porphyrins and their
isomers, Izv. Vysh. Uchebn. Zaved., Khim. Khim. Techn. 63 (2020) 51–57.
https://doi.org/10.6060/ivkkt.20206301.5957.
[
[
[
[
17] J.B. Kim, J.J. Leonard, F.R. Longo, Mechanistic study of the synthesis and spectral
properties of meso-tetraarylporphyrins, J. Am. Chem. Soc. 94 (1972) 3986–3992.
https://doi.org/10.1021/ja00766a056.
18] A.M. d’A R. Gonsalves, J.M.T.B. Varejão, M.M. Pereira, Some new aspects related to the
synthesis of meso-substituted porphyrins, J. Heterocycl. Chem. 28 (1991) 635–640.
https://doi.org/10.1002/jhet.5570280317.
19] Z. Sun, Y. She, R. Zhong, Synthesis of p-substituted tetraphenylporphyrins and
corresponding ferric complexes with mixed-solvents method, Front. Chem. Eng. China. 3
(2009) 457. https://doi.org/10.1007/s11705-009-0169-6.
20] O.V. Pelipets, Investigation of the thermodynamics of evaporation of ErCl3, EuBr2 and
EuCl2 and the structure of molecular forms according to high-temperature mass
spectrometry and gas electron diffraction, Ivanovo State University, 2000.
[
[
[
[
21] G. V. Girichev, A.N. Utkin, Y.F. Revichev, Modernization of the EMR-100 setup for the
studies of gases, Prib. Tekh. Eksp. 27 (1984) 187–190.
22] G. V. Girichev, S.A. Shlykov, Y.F. Revichev, Apparatus for studies of the molecular
structures of non-saturated compounds, Prib. Tekh. Eksp. 29 (1986) 167–169.
23] S.A. Shlykov, G. V. Girichev, A radiofrequency mass spectrometer based on APDM-1
unit for the mass range of 1-1600 amu, Prib. Tekh. Eksp. 31 (1988) 141–142.
24] E.G. Girichev, A. V. Zakharov, G. V. Girichev, M.I. Bazanov, Automation of a
physicochemical experiment: photometry and voltammetry, Izv. Vysh. Uchebn. Zaved.,
Tekst. Prom. 2 (2000) 142–146.
[
[
25] Yury V. Vishnevskiy, 2020, UNEX version 1.6, http://unexprog.org (accessed Sun Mar 01
2020), (n.d.).
26] T.H. Dunning, Gaussian basis functions for use in molecular calculations. III. Contraction
of (10s6p) atomic basis sets for the first-row atoms, J. Chem. Phys. 55 (1971) 716–723.
https://doi.org/10.1063/1.1676139.
[
27] S. Huzinaga, Gaussian‐ Type Functions for Polyatomic Systems. I, J. Chem. Phys. 42
(1965) 1293–1302. https://doi.org/10.1063/1.1696113.

[
28] P.C. Hariharan, J.A. Pople, The influence of polarization functions on molecular orbital
hydrogenation energies, Theor. Chim. Acta. 28 (1973) 213–222.
https://doi.org/10.1007/BF00533485.
[
[
29] M. Urban, V. Kellö, P. Čársky, Polarization functions for gaussian basis sets for the first
row atoms, Theor. Chim. Acta. 45 (1977) 205–213. https://doi.org/10.1007/BF00552682.
30] K.L. Schuchardt, B.T. Didier, T. Elsethagen, L. Sun, V. Gurumoorthi, J. Chase, J. Li, T.L.
Windus, Basis Set Exchange:ꢃ A Community Database for Computational Sciences, J.
Chem. Inf. Model. 47 (2007) 1045–1052. https://doi.org/10.1021/ci600510j.
[
[
31] T. Baše, J. Holub, J. Fanfrlík, D. Hnyk, P.D. Lane, D.A. Wann, Y. V. Vishnevskiy, D.
Tikhonov, C.G. Reuter, N.W. Mitzel, Icosahedral Carbaboranes with Peripheral
Hydrogen–Chalcogenide Groups: Structures from Gas Electron Diffraction and Chemical
Shielding in Solution, Chem. - A Eur. J. 25 (2019) 2313–2321.
https://doi.org/10.1002/chem.201805145.
32] Y. V. Vishnevskiy, Y.A. Zhabanov, New implementation of the first-order perturbation
theory for calculation of interatomic vibrational amplitudes and corrections in gas electron
diffraction, J. Phys. Conf. Ser. 633 (2015) 012076. https://doi.org/10.1088/1742-
6596/633/1/012076.
[
[
33] Y. V. Vishnevskiy, S. Blomeyer, C.G. Reuter, Gas standards in gas electron diffraction:
accurate molecular structures of CO2 and CCl4, Struct. Chem. (2019).
https://doi.org/10.1007/s11224-019-01443-5.
34] M.J. Frisch, G.W. Trucks, H.B. Schlegel, G.E. Scuseria, M.A. Robb, J.R. Cheeseman,
J.A. Montgomery Jr., T. Vreven, K.N. Kudin, J.C. Burant, J.M. Millam, S.S. Iyengar, J.
Tomasi, V. Barone, B. Mennucci, M. Cossi, G. Scalmani, N. Rega, G.A. Petersson, H.
Nakatsuji, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T.
Nakajima, Y. Honda, O. Kitao, H. Nakai, M. Klene, X. Li, J.E. Knox, H.P. Hratchian, J.B.
Cross, V. Bakken, C. Adamo, J. Jaramillo, R. Gomperts, R.E. Stratmann, O. Yazyev, A.J.
Austin, R. Cammi, C. Pomelli, J.W. Ochterski, P.Y. Ayala, K. Morokuma, G.A. Voth, P.
Salvador, J.J. Dannenberg, V.G. Zakrzewski, S. Dapprich, A.D. Daniels, M.C. Strain, O.
Farkas, D.K. Malick, A.D. Rabuck, K. Raghavachari, J.B. Foresman, J. V Ortiz, Q. Cui,
A.G. Baboul, S. Clifford, J. Cioslowski, B.B. Stefanov, G. Liu, A. Liashenko, P. Piskorz,
I. Komaromi, R.L. Martin, D.J. Fox, T. Keith, M.A. Al-Laham, C.Y. Peng, A.
Nanayakkara, M. Challacombe, P.M.W. Gill, B. Johnson, W. Chen, M.W. Wong, C.
Gonzalez, J.A. Pople, Gaussian 03 Revision B.03, Gaussian Inc Pittsburgh, (2003).
[
[
35] A.D. Becke, Density-functional thermochemistry. III. The role of exact exchange, J.
Chem. Phys. 98 (1993) 5648–5652. https://doi.org/10.1063/1.464913.
36] C. Lee, W. Yang, R.G. Parr, Development of the Colle-Salvetti correlation-energy
formula into a functional of the electron density, Phys. Rev. B. 37 (1988) 785–789.
https://doi.org/10.1103/PhysRevB.37.785.
[
[
37] N.B. Balabanov, K.A. Peterson, Systematically convergent basis sets for transition metals.
I. All-electron correlation consistent basis sets for the 3d elements Sc–Zn, J. Chem. Phys.
123 (2005) 64107. https://doi.org/10.1063/1.1998907.
38] K.A. Peterson, D. Figgen, M. Dolg, H. Stoll, Energy-consistent relativistic
pseudopotentials and correlation consistent basis sets for the 4d elements Y–Pd, J. Chem.
Phys. 126 (2007) 124101. https://doi.org/10.1063/1.2647019.

[
[
[
39] Precomputed vibrational scaling factors, NIST Comput. Chem. Comp. Benchmark
Database. (n.d.). https://doi.org/10.18434/T47C7Z.
40] R.D. Johnson, NIST Computational Chemistry Comparison and Benchmark Database,
NIST Standard Reference Database 101, (2019). https://doi.org/10.18434/T47C7Z.
41] R. Naik, P. Joshi, S.P.K. (nee Vakil), R.K. Deshpande, Facile synthesis of meso-
substituted dipyrromethanes and porphyrins using cation exchange resins, Tetrahedron. 59
(2003) 2207–2213. https://doi.org/https://doi.org/10.1016/S0040-4020(03)00245-X.
[
42] H. Yaman, A. Kayan, Synthesis of novel single site tin porphyrin complexes and the
catalytic activity of tin tetrakis(4-fluorophenyl)porphyrin overꢃ?-caprolactone, J. Porphyr.
Phthalocyanines. 21 (2017) 231–237. https://doi.org/10.1142/S1088424617500407.
[
[
43] W.C. Hamilton, Significance tests on the crystallographic R factor, Acta Crystallogr. 18
(1965) 502–510. https://doi.org/10.1107/S0365110X65001081.
44] P. Dechan, G.D. Bajju, P. Sood, U.A. Dar, Synthesis and single crystal structure of a new
polymorph of 5, 10, 15, 20-tetrakis-(4-chlorophenyl) porphyrin, H 2 TTPCl 4ꢃ:
Spectroscopic investigation of aggregation of H 2 TTPCl 4, Mol. Cryst. Liq. Cryst. 666
(2018) 79–93. https://doi.org/10.1080/15421406.2018.1512546.
[
[
45] T. Hökelek, D. Ülkü, N. Gündüz, M. Hayvali, Z. Kiliç, 5,10,15,20‐ Tetrakis(p‐
chlorophenyl)porphyrin, Acta Crystallogr. Sect. C. (1993).
https://doi.org/10.1107/S0108270193000782.
46] E. Matamala-Cea, F. Valenzuela-Godoy, D. González, R. Arancibia, V. Dorcet, J.-R.
Hamon, N. Novoa, Efficient preparation of 5,10,15,20-tetrakis(4-bromophenyl)porphyrin.
Microwave assisted v/s conventional synthetic method, X-ray and hirshfeld surface
structural analysis, J. Mol. Struct. 1201 (2020) 127139.
https://doi.org/10.1016/J.MOLSTRUC.2019.127139.

Table 1. Conditions of the GED/MS experiments.
Nozzle-to-plate distance, mm
Number of recorded films
Primary electron beam current, ꢀA
Wavelength of electrons, Å
Temperature of effusion cell, K
Exposure time, s
338
6
598
5
1.14
0.88
0.04086(3) 0.04142(4)
688(13)
100
677(8)
60
Residual gas pressure, Torr
–
–
6
7
-6
-
in the diffraction chamber
in mass-spectrometric block
1.4·10
7.9·10
1.3·10
–7
-
6.0·10
-1
Scattering angles range/ ∆s, Å
3.3-28.9/0.1 1.7-16.2/0.1
50(1) 50(1)
Ionization voltage, V
Table 2. Electron ionization mass spectrum of saturated vapors over H P-4C H F recorded
2
6
4
during experiments
+
I , calculated relative to parent ion [H P-4C H F]
rel
2
6
4
m/z,
a.m.u.
MS
(GED/MS)
1
(GED/MS)
L2=598 мм
Ions
(Knudsen) L =338 мм
+
[
[
[
H P-4C H F]
686
591
343
100
6
10
45
5
100
27
40
50
0.04
688
100
35
50
50
0.04
677
2
6
4
+
H P-3C H F]
2
6
4
2+
H P-4C H F]
2
6
4
U , V
ion
Conditions
U , kV
acc
T, K
618
a,b
Table 3. Relative energies (at B3LYP/pVTZ level), model and structural R -factors
for the
f
considered conformers of H P-4C H F.
2
6
4
Conformer model I
II
III
IV
Symmetry
C2v C2h C2h D2
-1
ꢁ
E, kJ mol [16]
0
0
0.47 0.53 0.94
2.36 2.75 5.08
a
R
f, mod.
b
, % [16]
Rf, str. , %
5.47 5.99 6.17 7.25
a
the disagreement factor Rf, mod. between two theoretical scattering intensities was calculated as
ꢘ
∑ꢅꢃꢄ ꢆ
ꢌꢄ ꢍ
− ꢄ ꢆꢇꢈꢉꢊꢋꢌꢄꢅꢍꢒꢊꢓꢉꢔꢕꢖꢗ
ꢅ
ꢇꢈꢉꢊꢋ ꢅ ꢎꢊꢏꢐ.ꢑ ꢅ
ꢂ
(2)
ꢀꢁ
=
∙ 100%
∑ꢅꢙꢄ ꢆ
ꢌꢄ ꢍ
ꢚꢘ
ꢅ
ꢇꢈꢉꢊꢋ ꢅ ꢎꢊꢏꢐ.ꢑ
where R is disagreement factor, ꢛ ꢝ
ꢌꢛ ꢍ
is theoretical molecular scattering intensity
f
ꢜ
ꢞꢟꢠꢡꢢ ꢜ ꢣꢡꢤꢥ.ꢦ
for conformer I, ꢛ ꢝ
ꢌꢛ ꢍ
is theoretical molecular scattering intensity for conformer j;
the disagreement factor Rf, str. between experimental and theoretical scattering intensities was
ꢜ
ꢞꢟꢠꢡꢢ ꢜ ꢧꢡꢨꢠꢩꢕꢪ
b
calculated by the formula (1).

a
Table 4. Experimental and theoretical structural parameters of H P-4C H X (X=F, Cl, Br) and metal complexes ZnTPP and PdTPP.
2
6
4
Parameter
H
2
P-4C
6
H
4
F
H
2
P-4C
6
H
4
Cl
H
2
P-4C
6
H
4
Br
ZnTPP
GED rh1
D2d
PdTPP.
GED rh1
D2d
B3LYP
GED rh1
r -r
h1
lexp
lcalc
a
X-ray,
X-ray,
X-ray,
/
pVTZ
C2v
C2v
c
c
c
r
r
r
Rf=5.47%
R 4.29% R =4.56%
f = f
[
44]
[45]
[46]
[
16]
[12]
[12]
b
N -C
N -C
2
1.364
1.374
1.458
1.432
1.351
1.367
1.408
1.401
1.499
1.399
1.392
1.385
1.355
1.011
1.077
1.083
110.7
106.4
106.4
125.4
108.2
105.7
110.7
1.362(5)
0.0038 0.056(2) 0.051 1.367
1.378
1.370
1.436
1.442
1.355
1.348
1.407
1.388
1.492
1.385
1.379
1.365
-
0.999
1.000
1.000
109.7
107.6
107.2
125.3
107.9
106.2
103.2
1.372
1.375
1.444
1.434
1.350
1.358
1.405
1.401
1.497
1.379
1.388
1.392
-
0.880
0.950
0.950
109.7
108.0
107.1
125.6
107.8
106.5
108.6
1
α1
α2
1.377(3)
1.446(3)
1.361(3)
1.407(3)
1.377(3)
1.373(5) 0.0007 0.054(2) 0.049 1.364
1.461(5) -0.001 0.059(2) 0.054 1.447
C -C
α1 β1
1.445(3)
1.358(3)
1.400(3)
C -C
1.437(5) 0.0001 0.057(2) 0.052 1.429
1.352(9) -0.0048 0.049(2) 0.045 1.345
1.370(8) -0.0006 0.051(2) 0.047 1.352
1.410(5) 0.0000 0.055(2) 0.050 1.398
1.402(5) 0.0001 0.055(2) 0.050 1.398
1.499(5) -0.0008 0.061(2) 0.055 1.495
1.403(5) 0.0004 0.054(2) 0.049 1.383
1.394(5) -0.0000 0.053(2) 0.048 1.381
1.387(5) 0.0001 0.053(2) 0.048 1.366
α2 β2
C -C
β1 β1
C -C
β2 β2
C -C
m
α1
C -C
m
α2
C -C1
1.489(8)
1.410(3)
1.403(3)
1.489(8)
1.398(3)
1.392(3)
m
C -C2
1
C -C3
2
C -C4
-
-
-
-
3
C-F
1.355(5) -0.0005 0.054(2) 0.049
-
N -H
1.012(5) 0.0015 0.072(5) 0.071 0.861
1.078(5) 0.0011 0.076(6) 0.076 0.930
1.084(5) 0.0001 0.077(6) 0.076 0.930
111.3(9)
105.4(1.2)
106.1(5)
125.7(5)
108.5(5)
105.2(1.2)
112.3(1.6)
-
1.086(6)
-
-
1.080(6)
-
2
C -H
β
ave
C -H
Ph
ave
N-C -C
110
α1 β1
109.4(3)
109.4(3)
N-C -C
107.1
106.9
125.6
108.0
106.0
109.9
α2 β2
C -C -C
-
-
α1 β1 β1
C -C -C
α2
125.3(8)
-
124.9(14)
-
α1
m
C -C -C
α2 β2 β2
C -N-C
α1
α1
106.6(5)
106.7(4)
C -N-C
α2
α2

-
24
d
8
2( +50)
C -C –C -C
3
72.9
71.2
69.7
62.1
80.3(3.6)
83.3(17.5)
α2
m
1

a
Bond lengths, (r -r ) vibrational corrections and l vibrational amplitudes in Å; bond and torsion
h1
e
angles in degrees.
b
2
2
1/2
Uncertainties given in parentheses were taken for distances as: [(2.5σ ) +σ
] , σ
=
scale
LS
scale
0
.002r, σ is a standard deviation in the least-squares refinement; 3σ for bond angles; 3σ ꢂl
LS LS LS 1
for amplitudes, where l is the amplitude of the first term in the corresponding group.
1
c
Average values calculated in this work using corresponding data
Estimated by Hamilton criterion (Fig. 5).
d

Graphical abstract

Fig. 1. Numbering/labeling scheme for H P-4C H F.
2
6
4

Fig. 2. Conformer models of H P-4C H F: C -two fold symmetry axis, σ - mirror plane.
2
6
4
2

Fig. 3. Experimental (circles) and theoretical (solid lines) molecular intensities sM(s) for H P-
2
4
C H F and the residuals ꢀsM(s).
6 4

Fig. 4. Experimental (circles) and theoretical (solid line) radial distribution functions f(r) for
H P-4C H F and residual curves ꢀf(r).
2
6
4