Infrared matrix isolation and theoretical studies of the hydrogen bonded complexes between nitrous acid and 1,1-dichloroethylene

Article abstract of DOI:10.1016/j.chemphys.2005.12.010

The complexes formed between trans and cis isomers of nitrous acid and 1,1-dichloroethylene (1,1-DCE) in argon matrixes have been identified and characterized by help of FTIR spectroscopy. The experimental spectra evidenced that trans- and cis-HONO isomer

Full text of DOI:10.1016/j.chemphys.2005.12.010

Chemical Physics 324 (2006) 689–698
www.elsevier.com/locate/chemphys
Infrared matrix isolation and theoretical studies of the hydrogen
bonded complexes between nitrous acid and 1,1-dichloroethylene
*
Adriana Olbert-Majkut , Zofia Mielke
Faculty of Chemistry, University of Wroclaw, Joliot-Curie 14, 50-383 Wroclaw, Poland
Received 26 October 2005; accepted 9 December 2005
Available online 18 January 2006
Abstract
The complexes formed between trans and cis isomers of nitrous acid and 1,1-dichloroethylene (1,1-DCE) in argon matrixes have been
identified and characterized by help of FTIR spectroscopy. The experimental spectra evidenced that trans- and cis-HONO isomers form
two types of complexes with different structures.
The optimization and spectral characteristics of the studied systems were carried out at the MP2 level of theory with 6-
311++G(2d,2p) basis set. The performed calculations resulted in five stationary points on the PES for both trans and cis-HONO com-
plexes. Two complexes are stabilized by the O–Hꢀ ꢀ ꢀp bond, the other two by the O–Hꢀ ꢀ ꢀCl bond and one complex by the bifurcated,
asymmetric Clꢀ ꢀ ꢀHꢀ ꢀ ꢀCl interaction. In one of the two complexes stabilized by the O–Hꢀ ꢀ ꢀCl hydrogen bond an additional C–Hꢀ ꢀ ꢀO
(for cis-HONO) or C–Hꢀ ꢀ ꢀN (for trans-HONO) hydrogen bond also exists. The topological analysis of the distribution of the charge
density by help of AIM theory confirmed the asymmetry of the Clꢀ ꢀ ꢀHꢀ ꢀ ꢀCl bifurcated hydrogen bond and the double O–Hꢀ ꢀ ꢀCl and
C–Hꢀ ꢀ ꢀO(N) interaction in one of the five structures. The values of the qb and $2qb indicate that the Clꢀ ꢀ ꢀHꢀ ꢀ ꢀCl bond is more asym-
metric in the cis-HONO complex than in the trans-HONO one. The comparison of the experimental frequencies with the calculated ones
for the five structures indicates that the trans- or cis-HONO complexes trapped in the matrixes correspond to the structures stabilized by
the O–Hꢀ ꢀ ꢀp bond or by the O–Hꢀ ꢀ ꢀCl bond.
Ó 2005 Elsevier B.V. All rights reserved.
Keywords: Dichloroethylene; Nitrous acid; Matrix isolation; FTIR; Hydrogen bond; Complexes; AIM; MP2 calculations
1. Introduction
of interest as they may affect the overall kinetics of photo-
addition reaction of OH radicals to relevant species in the
atmosphere.
Unsaturated hydrocarbons and their halogenated deriv-
atives are the major constituents of polluted urban environ-
ments. Vinylidene chloride (1,1-C2H2Cl2) is used
industrially for the production of poly(vinyl dichloroethyl-
ene) – PVDC and is classified as human carcinogen and
hepatotoxicant that exerts acute toxicity. Nitrous acid
(HONO) acts in atmosphere as a main source of hydroxyl
radicals (OH). The reaction of OH and (NO)x radicals with
hydrocarbons and organochlorines are of critical impor-
tance in the Earth’s troposphere. Molecular complexes
formed between HONO and 1,1-C2H2Cl2 (1,1-DCE) are
On the other hand, the weak hydrogen-bonded com-
plexes involving XHꢀ ꢀ ꢀp interaction are still the subject
of interest of present-day research [1]. They are usually
considered to be the initial stage of an electrophilic addi-
tion to alkene or alkyne, with an H-X orientation that is
perpendicular to the CC multiple bond. Such systems were
studied with Fourier transform microwave [2–6] and IR
spectroscopy in the gaseous state [7–11] by IR matrix isola-
tion spectroscopy [12–15] cryo-spectroscopy [16–18] or by
X-ray scattering in the crystal [19]. Theoretical ab initio
calculations have also been reported for these type of com-
plexes [20–23]. In the complexes of ethylene or acetylene
with OH proton donors such as water [24–26], nitric acid
*
Corresponding author. Tel.: +48 71 3757 305; fax: +48 71 3282 348.
E-mail address: olbert@wchuwr.chem.uni.wroc.pl (A. Olbert-Majkut).
0301-0104/$ - see front matter Ó 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.chemphys.2005.12.010

690
A. Olbert-Majkut, Z. Mielke / Chemical Physics 324 (2006) 689–698
[27] and nitrous acid [28] the presence of the OHꢀ ꢀ ꢀp hydro-
gen bond has been also evidenced. In spite of huge amount
of studies devoted to this subject, less attention has been
paid on the halogenated derivatives of unsaturated hydro-
carbons and on the influence of the substituent on the over-
all complex properties. More than twenty years ago,
Andrews et al. [29] reported the results of the matrix isola-
tion studies on C2HX complexes with HX (where X = Cl,
F). The authors concluded that the substitution of acety-
lene molecule decreases the proton-acceptor ability of CC
bond. These observations are in agreement with recent the-
oretical calculations performed by Li et al. [30] for the com-
plexes of ethylene and its fluorine derivatives with HF. The
authors predicted ca. 25% and 50% decrease of the interac-
tion strength for single (C2H3F) and double (1,1-C2H2F2)
substituted ethylene, respectively.
at MP2 level using the split-valence 6-311++G(2d,2p) basis
set augmented with diffuse and polarisation functions.
Vibrational frequencies and intensities for the monomers
and for the binary complexes were also obtained at the
MP2 level of theory. All interaction energies were corrected
for basis set superposition error (BSSE) by the Boys–Ber-
nardi [33] counterpoise correction scheme.
The topological analysis was performed to calculate the
charge density (q) and its second derivative Laplacian of
charge density ($2q) for bonds using Bader’s AIM theory
[34].
3. Results
3.1. Experimental spectra
In this paper we present the results of combined theoret-
ical and infrared matrix isolation studies of the complexes
formed between nitrous acid and 1,1-dichloroethylene. The
bonding interactions in the studied complexes are deter-
mined and classified with help of Atoms in Molecules
theory.
The spectra of the parent molecules are in agreement
with those previously reported [31,35,36]. Infrared spectra
of HONO/1,1-C2H2Cl2/Ar show a number of prominent
new absorptions as compared to the spectra of HONO
and 1,1-DCE monomers isolated in argon matrices.
Fig. 1a presents the spectra of the 1,1-C2H2Cl2/HONO/
Ar in the region of the OH stretching vibrations. As one
can see, three new strong bands marked as A or B appeared
at 3515.4, 3506.2 and 3494.5 cmꢁ1 in the vicinity of the
m(OH) stretching vibration of trans-HONO. The relative
intensities of these three bands are independent on matrix
concentration which suggests that they are due to the 1:1
HONOꢀ ꢀ ꢀ1,1-DCE complexes. After matrix annealing the
band at 3515.4 cmꢁ1 (B) slightly decreased with respect to
the bands observed at 3506.2 and 3494.5 cmꢁ1 (A), which
did not show noticeable changes. When the matrix was irra-
diated with the medium-pressure Hg lamp using k > 320 nm
radiation, the photolysis of the studied complexes was
observed. The bands marked as A decreased apparently fas-
ter than those labelled as B. The subsequent annealing of the
photolysed matrixes led to partial recovering of A bands.
The comparison of the spectra recorded directly after
matrix deposition with the spectra recorded after matrix
annealing and after matrix photolysis allowed us to identify
the B and A bands in other spectral regions. The bands
attributed to group A occurred at 3506.2, 3494.5, 1682.0,
1301.0, 1298.5, 818.5 and 631.5 cmꢁ1 and the B bands were
identified at 3515.4, 1679.0, 1274.5, 1272.5, 813.5, 626.5,
615.0 cmꢁ1. All above absorptions appeared in the neigh-
bourhood of the trans-HONO fundamentals and were
assigned to the perturbed trans-HONO vibrations in the
studied complexes. The bands belonging to groups A or B
were also identified in the vicinity of cis-HONO fundamen-
tals. The A bands appeared at 3361.0, 1628.5 and
678.5 cmꢁ1, while the B absorptions were observed at
3376.5 and 1626.4 cmꢁ1. All these bands were assigned to
the perturbed cis-HONO vibrations in cis-HONO. . .1,1-
DCE complex. Only one absorption was identified for the
bonded 1,1-C2Cl2H2 molecule. The absorption observed
at 843.7 cmꢁ1 that belongs to group A is attributed to the
perturbed dop(CH2) mode of 1,1-dichloroethylene in the
2. Experimental details
2.1. Matrix isolation studies
Crystalline ammonium nitrite, NH4NO2, was employed
as a source of gaseous HONO (NH4NO2 () HONO þ
NH3) and ND4NO2 was used as a source of DONO.
HONO/Ar and DONO/Ar mixtures were prepared in the
same way as previously described [31]. The liquid 1,1-
dichloroethylene (1,1-DCE) was obtained from Fluka with
specified purity 99.5%. The sample was degassed through 4
freeze–thaw cycles using liquid nitrogen followed by cryo-
genic distillation.
HONO/Ar or DONO/Ar and 1,1-C2H2Cl2/Ar gas mix-
tures were codeposited simultaneously through two sepa-
rate spray-on lines. The gas mixtures were sprayed onto a
gold-plated copper mirror held at 11 K by a closed cycle
helium refrigerator, Air Products, Displex 202. The
approximate HONO/Ar and DONO/Ar ratio was 1/800,
whereas the concentration of 1,1-DCE/Ar was varied in
the range 1/150 to 1/450. The deposition was monitored
by infrared spectrum of the matrix. After the infrared spec-
tra of the initial deposit have been recorded the sample was
subjected to the filtered radiation of a 200 W medium pres-
sure mercury arc (Philips CS200W2).
The spectra were registered at 0.5 cmꢁ1 resolution in
reflection mode, with a Bruker 113v FTIR Spectrometer.
2.2. Computational details
The ab initio calculations were carried out using the
GAUSSIAN-03 package of computer codes [32]. The struc-
tures of the trans-HONO, cis-HONO and 1,1-C2H2Cl2
monomers and their binary complexes were fully optimised

A. Olbert-Majkut, Z. Mielke / Chemical Physics 324 (2006) 689–698
691
Fig. 1. The m(OH) (a) and m(OD) (b) regions in the spectra of the HONO(DONO)/1,1-DCE/Ar matrices of approximate concentration 1/1/200 (B, C, D):
(B) spectra recorded after matrix deposition, (C) spectra recorded after matrix annealing, (D) spectra recorded after 30 min irradiation at k > 320 nm. For
comparison the spectra of HONO(DONO)/Ar matrices of 1/800 concentration are given (A).
complex with nitrous acid. The band is tentatively assigned
to complex with trans-HONO isomer, since the concentra-
tion of the trans complexes in the studied matrixes is higher
than the concentration of the cis ones [31].
Most of the above absorptions have their counterparts
in the spectra of 1,1-C2H2Cl2/DONO/Ar matrix. The
bands exhibit the same structure pattern and behaviour
as A and B bands detected in the spectra of non-deuterated
system. Fig. 1b presents the infrared spectra of the 1,1-
C2H2Cl2/DONO/Ar matrix in the region of the m(OD)
stretching vibration of trans-DONO isomer. The band
attributed to B group appears at 2598.0 cmꢁ1, while the
A group bands are observed at 2591.4 and 2582.3 cmꢁ1
.
In other spectral regions the perturbed trans-DONO vibra-
tions attributed to A group appeared at 2591.4, 2582.3,
1674.0, 1033.0, 1031.5 and 623.0 cmꢁ1 and the bands due
to B group were observed at 2598.0, 1671.0, 1017.5 and
764.5 cmꢁ1, respectively. Only three bands were identified
for the perturbed cis-DONO vibrations in complexes with
1,1-DCE; they appeared at 2500.0 and 830.0 cmꢁ1 (B
group) and at 2489.0 cmꢁ1 (A group).
All frequencies identified for the HONO complexes with
1,1-DCE and attributed to groups A and B are collected in
Table 1.
Table 1
The frequencies (cmꢁ1) observed for trans- and cis-HONO subunits in the complexes with 1,1-C2H2Cl2 isolated in solid argon
trans-HONO
cis-HONO
Assignment
HONO
C2H2Cl2–HONO
DONO
C2H2Cl2-DONO
HONO
C2H2Cl2-HONO
DONO
C2H2Cl2-DONO
3572.6
3568.5
3515.4 B
3506.2 A
3494.5 A
1682.0 A
1679.0 B
1301.0 A
1298.5 A
1274.5 B
1272.5 B
818.5 A
813.5 B
2635.0
2638.1
2598.0 B
2591.4 A
2582.3 A
1674.0 A
1671.0 B
1033.0 A
1031.5 A
1017.5 B
3412.4
3410.7
3376.5 B
3361.0 A
2524.0
2522.6
2500.0 B
2489.0 A
mOH
1689.1
1688.0
1265.8
1263.9
1682.6
1681.6
1013.9
1011.4
1634.0
1632.8
–
1628.5 A
1626.4 B
–
1622.0
1621.1
–
–
–
mN@O
dNOH
800.4
796.6
608.7
748.9
744.3
602.4
601.5
–
764.5 B
623.0 A
853.2
850.4
–
–
815.0
811.5
–
830.0 B
–
mN–O
dONO
sOH
631.5 A
626.5 B
615.0 B
–
549.4
638.4
678.5 A
–
1,1-C2H2Cl2
C2H2Cl2–HONO
843.7 A
873.8
–
–
–
–
–
–
dopCH2

692
A. Olbert-Majkut, Z. Mielke / Chemical Physics 324 (2006) 689–698
˚
3.2. Ab initio calculations
the C@C bond at the point deviated by 0.21, 0.30 A from
the centre of C@C toward C2(H2) atom in the AI, AII
˚
The calculated geometrical parameters for the trans- and
cis-HONO complexes with 1,1-DCE are reported in Tables
2 and 3. In Tables 4 and 5 the harmonic vibrational fre-
quencies computed for the optimized structures are
presented.
Five stationary points that were found for both trans-
and cis-HONO complexes with 1,1-dichloroethylene are
presented in Figs. 2 and 3. In all structures the OH group
of the acid acts as a proton donor toward 1,1-DCE
molecule.
trans-HONO complexes and by 0.16, 0.31 A in the AI,
AII complexes of cis-HONO.
In the second type of complexes denoted as B (see Table
2 and Figs. 2 and 3) the OH group interacts with one or
two chlorine atoms of the 1,1-dichloroethylene molecule
forming O–H1ꢀ ꢀ ꢀCl1 bond in BI, BII complexes and
three-centred, bifurcated Cl1ꢀ ꢀ ꢀH1ꢀ ꢀ ꢀCl2 bond in BIII com-
plex. In BI complexes the acid plane is perpendicular to the
1,1-DCE plane with the W(C1Cl1H1O1) dihedral angle of
88° and 89° for trans- and cis-HONO complexes, respec-
tively. The arrangement of trans- and cis-HONO subunits
with respect to 1,1-dichloroethylene in BI structure sug-
gests that, apart from the OH1ꢀ ꢀ ꢀCl1 interaction, there is
an additional, weak interaction between the C2–H2 group
and N or O2 atoms, which probably contributes to the sta-
bilisation energy of the complex. The H2ꢀ ꢀ ꢀN(or O2) dis-
Two T-shaped structures that are stabilized by the
OHꢀ ꢀ ꢀp interaction differ with the orientation of the
HONO plane with respect to the 1,1-DCE plane. The AI
structure is characterised by nearly perpendicular orienta-
tion of the HONO plane to the 1,1-DCE plane; the W
(C1C2NO1) dihedral angle is equal to 99° and 85° for trans-
and cis-HONO complexes, respectively. In the AII complex
the HONO molecule lies in the bisecting plane of the 1,1-
DCE leading to a parallel arrangement of the N–O1 and
C1@C2 bonds; the W(C1C2NO1) angle is equal to 0.9° for
trans- and 2.1° for cis-HONO complexes, respectively.
Both in the AI and AII complexes the OH bond does not
point to the centre of the C@C bond making the OHꢀ ꢀ ꢀp
interaction asymmetric. The H1ꢀ ꢀ ꢀC2 distance is shorter
˚
˚
tances are calculated to amount to 3.03 A or 3.21 A for
trans- or cis-HONO complexes, respectively. In the BII
complexes the nitrous acid is nearly coplanar with 1,1-
DCE; the deviation from the coplanarity is equal to 16°
for trans- and 17° for cis-HONO complex. The H1ꢀ ꢀ ꢀCl1
distance in BII trans-HONO complex is slightly longer
(by ca. 0.011 A) and in BII cis-HONO complex is slightly
shorter (by ca. 0.022 A) than in the corresponding BI trans-
and cis-HONO complexes. The third stable structure, BIII,
involves three-centered, ‘‘bifurcated’’ Cl1ꢀ ꢀ ꢀH1ꢀ ꢀ ꢀCl2 inter-
action. The two interacting molecules are coplanar, the tor-
˚
˚
˚
˚
than the H1ꢀ ꢀ ꢀC1 one by 0.116 A, 0.166 A and by 0.085,
˚
0.165 A for the AI, AII structures of trans and cis-HONO
complexes, respectively. The OH bond direction intersects
Table 2
The propertiesa of the trans-HONOꢀ ꢀ ꢀ1,1-C2H2Cl2 complexes calculated at MP2/6-311++G(2d,2p) level
Property
Monomer
AI
AII
BI
BII
0.971
BIII
0.969
r(H1O1)
0.967
0.972
0.972
0.971
r(O1N)
r(NO2)
r(C1C2)
r(C1Cl1)
r(C1Cl2)
r(C2H2)
R(H1ꢀ ꢀ ꢀC1)
R(H1ꢀ ꢀ ꢀC2)
R(H1ꢀ ꢀ ꢀCl1)
R(H1ꢀ ꢀ ꢀCl2)
R(H2ꢀ ꢀ ꢀN)
h(H1O1N)
1.440
1.178
1.330
1.733
1.733
1.076
1.425
1.182
1.334
1.729
1.731
1.077
2.459
2.343
1.431
1.181
1.335
1.729
1.729
1.077
2.490
2.324
1.421
1.184
1.329
1.743
1.728
1.077
1.431
1.181
1.329
1.743
1.728
1.077
1.424
1.183
1.329
1.734
1.737
1.076
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
2.400
3.029
101.52
111.19
114.49
–
2.411
2.590
2.822
–
–
–
–
–
101.43
110.88
114.72
101.03
111.20
114.96
160.54
156.22
–
101.20
111.09
115.03
176.31
151.61
–
101.68
111.06
114.39
101.59
111.12
114.25
–
h(O1NO2)
h (Cl1C1Cl2)
H(O1H1ꢀ ꢀ ꢀC1)
H(O1H1ꢀ ꢀ ꢀC2)
H(O1H1ꢀ ꢀ ꢀCl1)
H(O1H1ꢀ ꢀ ꢀCl2)
H(C2H2ꢀ ꢀ ꢀN)
W(C1C2NO1)
W(C1Cl1H1O1)
W(C1Cl1NO1)
–
–
–
–
–
–
–
–
–
–
–
166.78
–
105.14
–
159.69
156.08
138.91
–
–
–
–
–
–
–
–
99.02
–
0.90
–
–
88.00
164.00
0.10
ꢁ2.14
ꢁ1.64
DECP
–
–
ꢁ2.25
ꢁ1.57
ꢁ2.22
ꢁ1.63
ꢁ2.33
ꢁ1.63
ꢁ2.09
ꢁ1.53
CP
DE
ZPE
a
˚
Bond lengths in A, angles in deg, energy in kcal/mol.

A. Olbert-Majkut, Z. Mielke / Chemical Physics 324 (2006) 689–698
693
Table 3
The propertiesa of the cis-HONOꢀ ꢀ ꢀ1,1-C2H2Cl2 complexes calculated at MP2/6-311++G(2d,2p) level
Property
Monomer
AI
AII
BI
BII
0.979
BIII
r(H1O1)
0.976
0.980
0.981
0.979
0.980
1.373
1.191
1.330
1.715
1.720
1.078
r(O1N)
r(NO2)
r(C1C2)
r(C1Cl1)
r(C1Cl2)
r(C2H2)
R(H1ꢀ ꢀ ꢀC1)
R(H1ꢀ ꢀ ꢀC2)
R(H1ꢀ ꢀ ꢀCl1)
R(H1ꢀ ꢀ ꢀCl2)
R(H2ꢀ ꢀ ꢀO2)
h(H1O1N)
1.398
1.193
1.330
1.733
1.733
1.076
1.392
1.196
1.334
1.729
1.730
1.077
2.488
2.403
1.396
1.195
1.334
1.728
1.729
1.077
2.546
2.381
1.391
1.196
1.328
1.729
1.740
1.076
1.397
1.194
1.329
1.729
1.742
1.077
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
2.507
3.210
105.31
113.50
2.485
2.576
2.930
–
–
–
–
–
104.67
113.41
114.72
103.72
113.52
114.97
177.66
147.41
–
105.32
113.46
114.99
169.71
105.24
113.43
114.44
105.60
113.52
114.19
h(O1NO2)
h (Cl1C1Cl2)
H(O1H1ꢀ ꢀ ꢀC1)
H(O1H1ꢀ ꢀ ꢀC2)
H(O1H1ꢀ ꢀ ꢀCl1)
H(O1H1ꢀ ꢀ ꢀCl2)
H(C2H2ꢀ ꢀ ꢀO2)
W(C1C1NO1)
W(C1Cl1H1O1)
W(C1Cl1NO1)
114.43
–
–
–
–
–
–
–
–
–
–
–
–
–
–
158.70
–
–
–
177.71
151.63
179.86
117.37
–
–
–
–
–
119.46
85.00
–
149
–
89.00
–
–
–
–
2.10
–
–
163.00
–
–
3.50
DECP
–
–
ꢁ1.99
ꢁ1.41
ꢁ2.07
ꢁ1.53
ꢁ2.11
ꢁ1.54
ꢁ1.90
ꢁ1.42
ꢁ1.70
ꢁ1.24
CP
DE
ZPE
a
˚
Bond lengths in A, angles in deg, energy in kcal/mol.
Table 4
The frequencies, frequency shifts (cmꢁ1) and intensities (km/mol) of trans-HONO complexes with 1,1-C2H2Cl2 calculated at MP2/6-311++G(2d,2p) level
AI
AII
BI
BII
BIII
Assignment
m
Dm
m
Dm
m
Dm
m
Dm
m
Dm
3691(388)
1627(142)
1331(118)
812(118)
614(160)
672(44)
ꢁ98
ꢁ17
+42
+21
+34
+91
3687(364)
1633(145)
1329(89)
804(168)
601(155)
659(38)
ꢁ102
ꢁ11
+40
+13
+21
+78
3711(320)
1626(101)
1329(117)
823(149)
624(149)
625(82)
ꢁ78
ꢁ18
+40
+32
+44
+44
3714(359)
1635(107)
1321(268)
807(277)
601(223)
658(60)
ꢁ75
ꢁ9
3744(327)
1628(124)
1303(181)
816(150)
615(161)
639(63)
ꢁ35
ꢁ16
+14
+25
+35
+58
mOH
mN@O
dHON
mN–O
dONO
sOH
+32
+16
+21
+77
3314(2)
3201(5)
1635(55)
1421(2)
1117(87)
890(59)
816(177)
721(1)
ꢁ17
ꢁ9
3313(2)
3201(5)
1630(45)
1419(1)
1117(95)
869(58)
818(87)
729(8)
ꢁ17
ꢁ9
3321(2)
3209(4)
1648(65)
1426(0)
1112(92)
893(52)
808(115)
706(0)
0
3318(2)
3208(5)
1648(62)
1428(0)
1112(107)
889(44)
813(30)
705(0)
ꢁ3
ꢁ3
0
+5
+3
+12
0
+1
ꢁ3
ꢁ1
3321(1)
3210(4)
1650(72)
1423(0)
1111(68)
886(47)
809(141)
705(0)
0
masCH2
msCH2
mC@C
dCH2
rCH2
ꢁ2
ꢁ1
+2
0
+2
+9
ꢁ4
+1
ꢁ3
ꢁ4
ꢁ13
ꢁ2
ꢁ18
ꢁ5
0
+3
ꢁ3
+16
ꢁ5
+2
ꢁ5
0
+2
+13
+3
+17
0
+14
+2
ꢁ8
dopCH2
+5
masCCl2
twist CH2
msCCl2
+25
+2
+8
608(14)
485(8)
610(30)
479(8)
603(4)
471(5)
604(57)
472(6)
604(27)
469(5)
dopCCl2
sional W(C1Cl1NO1) angle being 0.9° and 3.5° for trans-
and cis-HONO complexes, respectively. The Cl1ꢀ ꢀ ꢀH1 and
H1ꢀ ꢀ ꢀCl2 distances in both trans- and cis-HONO complexes
slightly differ which indicates that the Cl1ꢀ ꢀ ꢀH1ꢀ ꢀ ꢀCl2 inter-
action exhibits some asymmetry. In trans-HONO complex
the difference between Cl1ꢀ ꢀ ꢀH1 and H1ꢀ ꢀ ꢀCl2 distances
plexes than in the corresponding structures of cis-HONO
ones which suggests higher stability of trans-HONO com-
plexes as compared with those formed by the cis-HONO
isomer.
In all calculated structures the geometrical parameters
of the two complex subunits are only slightly perturbed
by the complex formation. It is interesting to note that
the elongation of the O1–H1 bond is very similar (0.002–
˚
equals to 0.232 A and in the cis-HONO one it equals to
˚
0.354 A, respectively.
˚
For all optimized structures the calculated lengths of the
0.005 A) both in AI, AII and BI, BII, BIII complexes. This
hydrogen bonds are slightly shorter in trans-HONO com-
fact suggests similar strength of interaction in A and B type

694
A. Olbert-Majkut, Z. Mielke / Chemical Physics 324 (2006) 689–698
Table 5
The frequencies, frequency shifts (cmꢁ1) and intensities (km/mol) of cis-HONO complexes with 1,1-C2H2Cl2 calculated at MP2/6-311++G(2d,2p) level
AI
AII
BI
BII
BIII
Assignment
m
Dm
m
Dm
m
Dm
m
Dm
m
Dm
3550(243)
1586(110)
1349(13)
889(294)
634(41)
ꢁ115
ꢁ10
+21
+21
+14
+59
3550(247)
1584(65)
1345(22)
890(117)
626(53)
ꢁ115
ꢁ12
+17
+22
+6
3581(184)
1585(100)
1347(10)
892(302)
635(39)
ꢁ54
ꢁ11
+19
+24
+15
+44
3580(190)
1590(166)
1341(22)
870(441)
625(53)
ꢁ53
ꢁ16
+13
+2
+5
+46
3595(207)
1588(136)
1339(16)
888(385)
634(39)
ꢁ38
ꢁ14
+11
+20
+14
+38
mOH
mN@O
dHON
mN–O
dONO
sOH
740(61)
754(31)
+73
725(62)
727(64)
719(69)
3315(2)
3202(5)
1634(69)
1421(1)
1117(96)
884(105)
816(56)
716(4)
ꢁ6
3314(2)
3201(5)
1635(87)
1420(0)
1117(96)
860(219)
818(94)
702(12)
610(8)
ꢁ7
ꢁ9
ꢁ13
ꢁ3
+2
ꢁ17
+5
ꢁ2
+3
+9
3321(1)
3210(4)
1651(66)
1423(0)
1110(87)
885(40)
810(81)
703(0)
0
0
+3
0
ꢁ5
+8
ꢁ3
ꢁ1
ꢁ3
ꢁ3
3320(2)
3209(5)
1648(61)
1427(0)
1113(97)
892(40)
811(107)
704(6)
ꢁ1
ꢁ1
0
+4
ꢁ2
+15
ꢁ2
0
3321(1)
3210(4)
1649(71)
1423(0)
1113(91)
884(46)
809(51)
704(1)
0
0
masCH2
msCH2
mC@C
dCH2
rCH2
ꢁ8
ꢁ14
ꢁ2
+1
0
ꢁ2
+7
ꢁ3
0
+2
+7
+3
+12
+2
+14
dopCH2
masCCl2
twist CH2
msCCl2
609(11)
485(7)
604(11)
468(4)
604(10)
472(6)
ꢁ3
605(15)
468(5)
ꢁ2
480(7)
0
ꢁ3
dopCCl2
Fig. 2. The optimized structures of the 1,1-dichloroethylene complexes with trans-HONO.
of complexes. The additional interaction in BI complex is
reflected in larger perturbation of the N–O1 distances as
compared with the other optimized structures; shortening
of the N–O1 distance by 0.019 A and 0.007 A is calcu-
lated for trans- and cis-HONO BI complexes, respectively.
As one can see in Tables 2 and 3 the N–O1 bond length
is the most sensitive structural parameter to complex
formation in all optimized structures; it is shortened by
Tables 2 and 3 present the MP2 calculated binding ener-
gies of the studied complexes including the BSSE and
ZPVE corrections. As one can see, all complexes show
comparable strength of interaction, which indicates that
all may be present in the matrixes. According to MP2 cal-
culated binding energies, DECZPPE, the complexes formed by
trans isomer of nitrous acid are stronger than their cis-
HONO counterparts by 0.1–0.16 kcal/mol. Only for BIII
structures the difference in stability of trans-HONO and
cis-HONO complexes is larger amounting to 0.40 kcal/
mol, which is probably due to the higher asymmetry of
Cl1ꢀ ꢀ ꢀH1ꢀ ꢀ ꢀCl2 interaction in the cis-HONO complex than
in the trans-HONO one (see Figs. 2 and 3).
˚
˚
˚
˚
0.009–0.019 A in trans-HONO and by 0.001–0.006 A in
cis-HONO upon complex formation. The other geometri-
cal parameters of the two complex subunits show negligible
perturbations in the complex as compared to their mono-
mers values.

A. Olbert-Majkut, Z. Mielke / Chemical Physics 324 (2006) 689–698
695
Fig. 3. The optimized structures of the 1,1-dichloroethylene complexes with cis-HONO.
In Table 6 the topological properties of the electronic
charge density at BCPs found for all studied complexes
are collected. Positive $2qb and small values of the electron
density at the BCP of O1H1ꢀ ꢀ ꢀp, O1H1ꢀ ꢀ ꢀCl and
Cl1ꢀ ꢀ ꢀH1ꢀ ꢀ ꢀCl2 bonds confirm that only closed shell interac-
tions are responsible for the presence and stability of opti-
mized structures. The analysis of BCPs confirms the
existence of O1H1ꢀ ꢀ ꢀp bonds in all A-type complexes,
O1H1ꢀ ꢀ ꢀCl1 bonds in BI, BII structures and Cl1ꢀ ꢀ ꢀH1ꢀ ꢀ ꢀCl2
interaction in BIII structure. Additionally, the C2H2ꢀ ꢀ ꢀNO2
(for trans-HONO complex) and the C2–H2ꢀ ꢀ ꢀO2–N (for cis-
HONO complex) interaction is predicted in BI structures,
which agrees well with the results of the geometrical
parameters analysis. The additional weak interaction in
BI complex is probably responsible for slightly larger sta-
bility of this structure with respect to the BII and BIII
structures (see Tables 2 and 3).
4. Discussion
The product bands observed in the spectra of the 1,1-
DCE/HONO/Ar and 1,1-DCE/DONO/Ar matrixes, in
the vicinity of the trans-HONO(DONO) and cis-HONO-
(DONO) absorptions, are assigned with confidence to the
1:1 trans-HONOꢀ ꢀ ꢀ1,1-DCE and cis-HONOꢀ ꢀ ꢀ1,1-DCE
complexes, respectively.
The A and B band sets may be due to the multiple trap-
ping site effects or to the presence of complexes of different
structures. The most reliable way of distinguishing isomeric
splitting from multiple trapping site effects is to vary the
matrix. However this test is not definitive as the struc-
tures of weak complexes characterized by flat potential
surface near the minimum may be matrix dependent [37–
39]. The preliminary experiments that we performed for
C2H2Cl2ꢀ ꢀ ꢀHONO in solid nitrogen suggests that this is
the case for the complexes that are the subject of our stud-
ies. The studies in nitrogen matrixes did not allow us to dis-
tinguish site splitting from isomeric splitting. However on
the basis of the arguments presented below we assigned
the A and B band sets observed in the spectra of 1,1-
C2H2Cl2/HONO/Ar matrixes to the complexes of different
structures. First, the frequency difference between the A
and B components in the m(OH) region is relatively large
suggesting that the two bands sets are not due to the site
splitting but to isomeric complexes. The difference between
the B absorption and the lower component of the A dou-
Table 6
The values of electron density (qBCP) and Laplacian ($2qBCP) calculated
for the complexes of trans- and cis-HONO with 1,1-C2Cl2H2
Complexes
Bond type
qb/10ꢁ2
$2qb/10ꢁ2
trans-HONO
AI
AII
BI
O–Hꢀ ꢀ ꢀp
1.4994
1.5052
1.5378
0.3530
1.5016
1.0222
0.6191
3.929
3.888
4.733
1.376
4.705
3.436
2.319
O–Hꢀ ꢀ ꢀp
O–Hꢀ ꢀ ꢀCl1
C–Hꢀ ꢀ ꢀN@O2
O–Hꢀ ꢀ ꢀCl1
O–Hꢀ ꢀ ꢀCl1
O–Hꢀ ꢀ ꢀCl2
BII
BIII
cis-HONO
AI
AII
BI
O–Hꢀ ꢀ ꢀp
1.3581
1.3476
1.2252
0.5614
1.2909
1.0575
0.4681
3.5500
3.483
3.782
2.070
4.193
3.466
1.692
O–Hꢀ ꢀ ꢀp
O–Hꢀ ꢀ ꢀCl1
C–Hꢀ ꢀ ꢀO2@N
O–Hꢀ ꢀ ꢀCl1
O–Hꢀ ꢀ ꢀCl1
O–Hꢀ ꢀ ꢀCl2
BII
BIII
blet observed in the m(OH) region is equal to 20.9 cmꢁ1
.

696
A. Olbert-Majkut, Z. Mielke / Chemical Physics 324 (2006) 689–698
Among the HONO complexes studied so far
[28,31,35,40,41] the largest site splitting of the m(OH)
absorption was observed for the trans-HONO–SO2 system
and was equal to 8.4 cmꢁ1. On the other hand the differ-
ence between the m(OH) frequencies of the two HON-
Oꢀ ꢀ ꢀallene isomeric complexes [41] was found to be equal
to 19.1 cmꢁ1, so, was comparable with the 20.9 cmꢁ1 value.
Second, in the spectra of all cis-HONO complexes studied
so far, the OH stretching vibration was observed as a single
band only. The appearance, in the spectra of the cis-
HONO complexes with 1,1-C2H2Cl2, two OH stretching
absorptions with slightly smaller frequency difference
(15.5 cmꢁ1) than that observed for trans-HONO complexes
also supports the assignment of the A and B band sets to
two isomeric complexes. Moreover, the bands belonging
to groups A and B exhibit different shifts with respect to
monomer bands in various spectral regions. In the region
of the m(N@O) mode the A bands of trans- and cis-HONO
exhibit smaller shifts than B bands whereas in all other
regions (m(OH), d(HON), m(N–O) and d(ONO)) larger
shifts are observed for the A bands than for their B coun-
terparts. The A and B bands sets show also different
response to UV irradiation [42]. The A bands decrease sig-
nificantly after 10 min of irradiation, while B absorptions
are only slightly affected. Annealing of the photolysed
matrices leads to partial recovery of A bands. The photol-
ysis of matrix with broad band irradiation should not lead
to such a different response of the complex of the same
structure trapped in two different sites. The site-selective
behaviour is usually observed after narrow-band (usually
IR) irradiation. On the other hand there are reported
numerous examples of different rates of the photolysis or
isomerization processes for the isomers or conformers
being irradiated with broad band irradiation. All the above
facts led us to the conclusion that the A, B band sets are
due to complexes of different structures.
ponents and B band (20 and 9 cmꢁ1 for the two components)
is also in accord with the calculated value (ca. 20 cmꢁ1). The
computed m(OH) frequency shifts for the A and B types of
complexes are overestimated which can be due to neglecting
anharmonicity in calculations and/or to relatively strong
influence of environment on the HONOꢀ ꢀ ꢀ1,1-DCE complex
and, particularly, on the polar 1,1-dichloroethylene mole-
cule. The frequency shift predicted for the OH stretching
vibration in the BIII structure (35 cmꢁ1) is quite smaller than
those observed for A and B bands and allows us to exclude
the presence of BIII in the matrix; the matrix environment
should not favour the formation of this complex.
The A and B bands due to the perturbed OH stretching
vibrations of cis-HONO complexes show similar shifts pat-
tern as the corresponding bands of trans-HONO com-
plexes. The A band exhibits larger shift with respect to
the corresponding band of HONO monomer (50.6 cmꢁ1
)
than the B band (35.1 cmꢁ1) and the bands are assigned
to A and B type of complexes, respectively.
The other perturbed HONO vibrations provide little
information on the structures of the complexes present in
matrixes; the calculations predict (Tables 4 and 5) small
frequency shift of the particular mode in the same direction
(toward higher or lower frequencies) for all optimized
structures. Some information on the complex structure
provides the identified out of plane CH2 vibration of 1,1-
DCE that occurs at 843.7 cmꢁ1 and is assigned to A com-
plex. The 843.7 cmꢁ1 band is ca. 30 cmꢁ1 shifted toward
lower frequencies with respect to the corresponding band
of the 1,1-DCE monomer. For all optimized structures,
except AII, the calculations predict the shift of the out of
plane CH2 vibration toward higher frequencies upon com-
plex formation and only for AII the low frequency shift is
predicted. The observed shift of the out of plane CH2 bend-
ing mode toward low frequencies suggests that the A group
of bands is due to AII complex although the presence of
the AI structure cannot be excluded. So, the comparison
of the calculated and experimental frequencies allows us
to conclude that two types of complexes are trapped in
the matrixes, one type involves the O–Hꢀ ꢀ ꢀp bond and
has most probably the AII structure and the second type
involves O–Hꢀ ꢀ ꢀCl bond and is characterized by BI or
BII structure. However the existence of the AI complexes
in the studied matrixes cannot be excluded.
The calculations predicted five stable trans- and cis-
HONO complexes with comparable binding energies but
we identified in the matrixes only two types of complexes
for each isomer. The existence of the other structures in
the matrixes cannot be completely excluded. We identified
the complexes on the basis of the perturbed HONO vibra-
tions mainly. The calculations show that the HONO vibra-
tions in all five complexes show similar perturbations (the
frequencies are shifted in the same direction). So, the
absorptions due to different structures may overlap obscur-
ing the presence of the other structures. On the other hand
it is known that the weak complexes with comparable sta-
bilization energy and flat Potential Energy Surface near the
As discussed earlier, ab initio calculations predict stability
of two T-shaped complexes with O1–H1ꢀ ꢀ ꢀp interaction (AI,
AII), two with O1–H1ꢀ ꢀ ꢀCl1 bond (BI, BII) and one complex
with bifurcated Cl1ꢀ ꢀ ꢀH1ꢀ ꢀ ꢀCl2 bond (BIII). The calculations
show that the perturbation of the OH stretching vibrations
upon complex formation (Dm(OH) = mcomp ꢁ mmon
)
decreases in the order: AI ꢂ AII > BI ꢂ BII > BIII. For
trans-HONO complexes the calculated Dm(OH) values are
equal to ꢁ98, ꢁ102 cmꢁ1 for the AI, AII structures; to
ꢁ78, ꢁ75 cmꢁ1 for the BI, BII ones and to ꢁ35 cmꢁ1 for
the BIII structure. The comparison of the calculated fre-
quency shifts with those observed for the B and A bands in
the OH stretching region of the matrix spectra suggests, that
the 3515.4 cmꢁ1 band (B) of trans-HONO complex corre-
sponds to one of the BI, BII complexes and the 3506.2,
3494.5 cmꢁ1 doublet (A) to one of the AI, AII ones. The
two components of A doublet are 76, 64 cmꢁ1 andthe B band
is 55 cmꢁ1 red shifted with respect to the OH stretch of trans-
HONO monomer [43] in accord with the predicted order of
the OH stretch perturbation in A and B complexes. The
observed frequency difference between the A doublet com-

A. Olbert-Majkut, Z. Mielke / Chemical Physics 324 (2006) 689–698
697
minimum are very sensitive to external factors. Different
matrixes may stabilize different structures of these types
of complexes. Ab initio calculations reported here indicate
the shallowness of the PES near the minima both for the
trans- and cis-HONO complexes. So, different matrix envi-
ronments may constrain one or more favourite structures.
The preliminary studies of the complexes in solid nitrogen
seem to confirm this suggestion.
The comparison of the studied complexes with that
formed by ethylene with HONO shows that substitution
of H atoms by Cl atoms weakens the O–Hꢀ ꢀ ꢀp interaction.
As already discussed, the m(OH) vibration in the T-shaped
complex between trans-HONO and 1,1-DCE is ca. 70 cmꢁ1
red shifted from the corresponding HONO monomer mode
while in the analogous complex with C2H4 the red shift
increases up to 137 cmꢁ1 indicating stronger hydrogen
bond in the latter complex [28]. Similar effect was observed
by Andrews et al. for the complexes of acetylene and chlo-
roacetylene with HF. The shift of the m(HF) stretching fre-
quency increases by 18 cmꢁ1 when going from
HFꢀ ꢀ ꢀC2HCl complex to HFꢀ ꢀ ꢀC2H2 one [13]. On the other
hand, the accumulation of the double bonds strengthens
the OHꢀ ꢀ ꢀp interaction. The Dm(OH) of trans-HONO in
complex with allene is equal to ꢁ164 cmꢁ1 [41].
the studied complexes confirmed the additional interaction
in BI complex (see Table 6). The calculations demonstrate
that the Bond Critical Point appeared between H2 atom
and acceptor atom (O2 or N). The charge density and the
Laplacian at the BCPs are equal to 0.0059 au and 0.0192
au, respectively, for trans-HONO complex and 0.0056 au
or 0.02070 au, respectively, for cis-HONO structure. Both
values are in the range required for hydrogen bond
(0.002–0.04 au for qb and 0.15–0.02 au for $2qb) [44].
The application of Atoms in Molecule theory confirmed
the unequivalency of Cl atoms in Cl1ꢀ ꢀ ꢀH1ꢀ ꢀ ꢀCl2 bridge
predicted for BIII complex. As discussed earlier, the anal-
ysis of the geometrical parameters indicated shorter dis-
tance between H1 and Cl1 atoms than between H1 and
˚
Cl2. The corresponding values are equal to 2.590, 2.822 A
˚
for trans-HONO complex and 2.576, 2.930 A for cis-
HONO system. These parameters correlate well with the
qb and $2qb values. The charge density calculated for the
shorter (H1ꢀ ꢀ ꢀCl1) and longer (H1ꢀ ꢀ ꢀCl2) bond path
amounts to 0.0102 and 0.0062 au, respectively for trans-
HONO complex. Analogically, the Laplacians at the dis-
cussed BCPs are equal to 0.0344 au (for H1ꢀ ꢀ ꢀCl1) and
0.0232 au (for H1ꢀ ꢀ ꢀCl2). In turn, for cis-HONO BIII com-
plex the qb value is predicted to be 0.0106 au for H1ꢀ ꢀ ꢀCl1
and 0.0047 au for H1ꢀ ꢀ ꢀCl2 while the $2qb values amount
to 0.0347 au and 0.0169 au for H1ꢀ ꢀ ꢀCl1 and H1ꢀ ꢀ ꢀCl2
bonds, respectively. The comparison of qb and $2qb calcu-
lated for discussed BCPs in trans- and cis-HONO com-
plexes confirmed larger asymmetry of Cl1ꢀ ꢀ ꢀH1ꢀ ꢀ ꢀCl2 in
cis-HONO complex than in trans-HONO one.
Recently Li et al. [30] have studied theoretically the F
substituent effect on the Hꢀ ꢀ ꢀp bond in T-shaped complexes
between HF and C2H4ꢁnFn (n = 0, 1, 2). According to their
calculations the interaction energies change in the order
ꢁ4.18, ꢁ3.07 and ꢁ2.46 kcal/mol for the C2H4ꢀ ꢀ ꢀHF,
C2H3Fꢀ ꢀ ꢀHF and 1,1-C2H2F2ꢀ ꢀ ꢀHF complexes, respec-
tively. The authors also predicted that in 1,1-C2H2F2ꢀ ꢀ ꢀHF
complex, the intersection point between HF axis and C@C
double bond deviates from the middle point of C@C by
5. Conclusions
˚
about 0.3 A toward the unsubstituted carbon atom direc-
The ab initio calculations, performed at MP2 level,
indicate that both trans- and cis-HONO isomers form with
1,1-dichloroethylene three types of hydrogen bonded com-
plexes; one involving OHꢀ ꢀ ꢀp bond, the second one being
stabilized by OHꢀ ꢀ ꢀCl interaction and the third type of
complexes with three centred, bifurcated Clꢀ ꢀ ꢀHꢀ ꢀ ꢀCl bond.
For the complexes with OHꢀ ꢀ ꢀp interaction two stationary
points are predicted, which are characterised by perpendic-
ular (AI) or parallel (AII) orientation of HONO plane with
respect to the 1,1-DCE plane. For O–Hꢀ ꢀ ꢀCl complexes
two stationary points were found that correspond to the
planar (BI) or non-planar (BII) geometry. The binding
energies corrected for BSSE and ZPVE have similar values
for all complexes and vary in the range 1.53–1.64 kcal/mol
for trans-HONO complexes and 1.24–1.54 kcal/mol for cis-
HONO ones. The geometrical parameters analysis sug-
gests that in BI structure an additional interaction exists
between the C–H bond of 1,1-DCE and the N or O atoms
(in trans- and cis-HONO complexes, respectively) of the
acid molecule which additionally stabilizes this complex.
The topological analysis of the charge density performed
by help of the AIM theory confirms this suggestion and
shows that the C–Hꢀ ꢀ ꢀO, C–Hꢀ ꢀ ꢀN interactions in the BI
complexes are of hydrogen bond nature.
tion, making the interaction asymmetric. This result is in
accord with our calculations for the AI, AII complexes
between HONO and 1,1-DCE. For AI complexes the devi-
˚
ation is predicted to be equal 0.21 and 0.31 A, for trans-
and cis-HONO complexes, respectively. The reason of the
asymmetry is the p-p conjugate effect (p electrons of X
atom transfer to carbon–carbon double bond) in the 1,1-
C2H2F2[30] or 1,1-C2H2Cl2 subunit. The p-p conjugation
in 1,1-DCE effects the OHꢀ ꢀ ꢀp hydrogen bond parameters
in two ways. First, p-electrons cloud is pushed to the C2
atom and OHꢀ ꢀ ꢀp bond is also shifted in the same direc-
tion. Second, the small deviation (5° and 9° for the trans
and cis-HONO AI complex, respectively) of HONO and
1,1-DCE planes from the perpendicular mutual orientation
can be considered as effect of the small deviation of the two
lobes of p electron cloud from the molecular vertical plane
passing through C@C bond.
As discussed above, the theoretical data, particularly the
analysis of geometrical parameters, indicate that BI com-
plex is stabilized by relatively strong OHꢀ ꢀ ꢀCl interaction
and very weak C–Hꢀ ꢀ ꢀO(N) interaction, while for AI, AII
and BII structures only one type of interaction is predicted
(OHꢀ ꢀ ꢀp or OHꢀ ꢀ ꢀCl, respectively). The AIM analysis of

698
A. Olbert-Majkut, Z. Mielke / Chemical Physics 324 (2006) 689–698
[15] L. Andrews, J. Mol. Struct. 100 (1983) 281.
The FTIR matrix isolation studies indicate that two
[16] K.G. Tokhadze, N.A. Tkhorzheskaya, J. Mol. Struct. 270 (1992) 351.
[17] K.G. Tokhadze, in: R.J.H. Clark, R.E. Hester (Eds.), Advances in
Spectrocopy, vol. 23, Wiley, New York, 1995, and references therein.
[18] W.A. Herrebout, B.J. Everaert, B.J. van der Veken, M.O. Bulanin, J.
Chem. Phys. 107 (1997) 8886.
[19] D. Mootz, A. Deeg, J. Am. Chem. Soc. 114 (1992) 5887.
[20] M.J. Frisch, J.A. Pople, J.E. Del Bene, J. Chem. Phys. 78 (1983) 4083.
[21] T.H. Tang, Y.P. Cui, Can. J. Chem. 74 (1996) 1162.
[22] H.C. Kang, Chem. Phys. Lett. 254 (1996) 135.
types of complexes are stabilized in the matrixes: the com-
plex involving OHꢀ ꢀ ꢀp interaction (most probably A1
structure) and the complex stabilized by OHꢀ ꢀ ꢀCl bond
(BII or BIII structure). The perturbations of the HON
group vibrations in the HONO complexes with 1,1-DCE
molecule indicate that the trans-HONO isomer forms
slightly stronger complexes than the cis-HONO one. The
ab initio calculations predict ca. 0.1 kcal/mol lower binding
energy for trans-HONO complexes than for cis-HONO
ones; the exception is the BIII complex, for which the cal-
culated difference in binding energies between trans- and
cis-HONO complexes amounts to 0.4 kcal/mol. This
results probably from the higher asymmetry of Clꢀ ꢀ ꢀHꢀ ꢀ ꢀCl
interaction in cis-HONO complex as compared with the
complex formed by trans-HONO. According to the topo-
logical analysis of the charge densities and the Laplacians,
in cis-HONO complex BIII the interaction of OH group
with one Cl atom is twice as strong as with the other Cl
atom whereas in the corresponding trans-HONO structure
the discrepancy between these values does not exceed 40%.
[23] K.C. Lopes, F.S. Pereira, M.N. Ramos, R.C.M. De Arauno,
Spectrochim. Acta A 57 (2001) 1339.
[24] A. Engdahl, B. Nelander, Chem. Phys. Lett. 113 (1985) 49.
[25] A. Engdahl, B. Nelander, J. Phys. Chem. 92 (1988) 5642.
[26] P. Tarakeshwar, H.S. Choi, S.J. Lee, J. Chem. Phys. 111 (1999) 5838.
[27] Z. Mielke, L. Schriver-Mazzuoli, A. Schriver, J. Phys. Chem. A 101
(1997) 4560.
[28] M. Krajewska, Z. Mielke, K.G. Tokhadze, J. Mol. Struct. 404 (1997)
47.
[29] L. Andrews, G.L. Johnson, B.J. Kelsall, J. Phys. Chem. 86 (1982)
3374.
[30] R.Y. Li, Z.R. Li, D. Wu, Y. Li, W. Chen, C.C. Sun, J. Chem. Phys.
121 (2004) 8775.
[31] Z. Mielke, K.G. Tokhadze, Z. Latajka, E. Ratajczak, J. Phys. Chem.
100 (1996) 539.
[32] M.J. Frish, G.W. Trucks, H.B. Schlegel, G.E. Scuseria, M.A. Robb,
J.R. Cheesman, V.G. Zakrzewski, J.A. Montgomery Jr., R.E.
Stratmann, J.C. Burant, S. Dapprich, J.M. Millam, A.D. Daniels,
K.N. Kudin, M. Strain, O. Farkas, J. Tomasi, V. Barone, M. Cossi,
R. Cammi, B. Mennucci, C. Pomelli, C. Adamo, S. Clifford, J.
Ochterski, G.A. Petersson, P.Y. Ayala, Q. Cui, K. Morokuma, D.K.
Malick, A.D. Rabuck, K. Raghavachari, J.B. Foresman, J. Cioslow-
ski, J.V. Otriz, A.G. Baboul, B.B. Stefanov, G. Liu, A. Liashenko, P.
Piskorz, I. Komaromi, M. Gomperts, R.L. Martin, D.J. Fox, T.
Keith, M.A. Al-Laham, C.Y. Peng, A. Nanayakkara, M. Challa-
combe, P.M.W. Gill, B. Johnson, W. Chen, M.M. Wong, J.L.
Andres, C. Gonzales, M. Head-Gordon, E.S. Replogle, J.A. Pople,
Gaussian 98, Revision A.9, Gaussian Inc., Pittsburgh, PA, 1998.
[33] S.F. Boys, F. Bernardi, Mol. Phys. 19 (1970) 553.
[34] R.F.W. Bader, Atoms in Molecules, a Quantum Theory, Oxford
Science Publication/Clarendon Press, London, 1990.
[35] Z. Mielke, Z. Latajka, A. Olbert-Majkut, R. Wieczorek, J. Phys.
Chem. 104 (2000) 3746.
Acknowledgement
A.O-M gratefully acknowledges a grant of computer
time from the Wroclaw Center for Networking and Super-
computing, and thanks the Foundation for Polish Science
for financial support.
References
[1] S. Furutaka, S. Ikawa, J. Chem. Phys. 117 (2002) 751.
[2] P.W. Fowler, A.C. Legon, J.M.A. Thumwood, E.R. Waclawik,
Chord. Chem. Rev. 197 (2000) 231.
[3] P.D. Aldrich, A.C. Legon, W.H.J. Flygare, J. Chem. Phys. 75 (1981)
2126.
[4] S.G. Kukolich, P.D. Aldrich, J. Chem. Phys. 78 (1983) 3552.
[5] A.C. Legon, D.J. Millen, Faraday Discuss. 73 (1982) 71.
[6] A.C. Legon, Chem. Soc. Rev. 19 (1990) 1971.
[7] J.A. Shea, W.H. Flygare, J. Chem. Phys. 76 (1982) 4857.
[8] W.G. Read, W.H. Flygare, J. Chem. Phys. 76 (1982) 2238.
[9] B. Mikulskiene, A. Gruodis, V. Sablinskas, B. Nelander, J. Mol.
Struct. 215 (2001) 563.
[36] H.E. Cortland, G.C. Pimentel, J. Phys. Chem. 90 (1986) 5485.
[37] Y. Haas, U. Samuni, in: G. Wancock, R. Compton (Eds.), Research
in Chemical Kinetics, Blackwell Science, Oxford, 1998.
[38] L. Schriver-Mazzuoli, A. Schriver, M. Wierzejewska-Hnat, Chem.
Phys. 199 (1995) 227.
[39] L. Nord, J. Mol. Struct. 96 (1982) 19.
[40] M. Wierzejewska, Z. Mielke, R. Wieczorek, Z. Latajka, 228 (1998)
17.
[10] B. Mikulskiene, A. Gruodis, V. Sablinskas, B. Nelander, Spectro-
chim. Acta A 59 (2003) 733.
[41] M. Krajewska, Z. Latajka, Z. Mielke, K. Mierzwicki, A. Olbert-
Majkut, M. Sałdyka, J. Phys. Chem. B 108 (2004) 15578.
[42] A. Olbert-Majkut, Z. Mielke, in preparation.
[43] The centre of the 3572.6, 3568.5 cmꢁ1 doublet was assumed as the OH
stretching frequency of the trans-HONO monomer.
[11] Z. Kisiel, P.W. Fowler, A.C. Legon, Chem. Phys. Lett. 176 (1991) 446.
[12] A.J. Barnes, J.B. Davis, H.E. Hallam, J.D.R. Howells, J. Chem. Soc.
Faraday Trans. 2 69 (1973) 246.
[13] L. Andrews, G.L. Johnson, B.J. Kelsall, J. Chem. Phys. 76 (1982)
5767.
[44] U. Koch, P.L.A. Popelier, J. Phys. Chem. 99 (1995) 9747.
[14] A.J. Barnes, J. Mol. Struct. 100 (1983) 259.