Crystal and molecular structure of the quinuclidine betaine with p-hydroxybenzoic acid complex studied by X-ray diffraction, DFT, FTIR, and NMR methods

Article abstract of DOI:10.1016/j.molstruc.2009.12.043

Quinuclidine betaine (1-carboxymethyl-1-azabicyclo[2.2.2]octane inner salt, QNB) forms a complex with p-hydroxybenzoic acid (HBA) at the 1:1 ratio. The crystals are triclinic, space group Pover(1, ?), with two symmetry non-equivalent QNB·HBA complexes linked by a sequence of four O-H···O hydrogen bonds into a zigzag chain. Both oxygen atoms of the carboxylate groups of two QNB are linked with two HBA molecules through the COO···HOOC hydrogen bonds of 2.561(2), and 2.556(2) ?, and the COO···HO hydrogen bonds of 2.609(2) and 2.687(2) ?. A trio ABC band at ca. 2800, 2550, 1910 cm^-1 observed in the FTIR spectrum is characteristic of a medium-strong hydrogen bond in carboxylic acids. The second-derivative IR spectrum confirms the presence of two non-equivalent C{double bond, long}O and two COO groups. The molecular structures of the 1:1 and 2:2 complexes have been optimized by the B3LYP/6-31G(d,p) approach. The experimental and predicted, by GIAO/B3LYP/6-31G(d,p), ¹H and ¹³C chemical shifts correlate linearly.

Full text of DOI:10.1016/j.molstruc.2009.12.043

Journal of Molecular Structure 967 (2010) 80–88
Contents lists available at ScienceDirect
Journal of Molecular Structure
journal homepage: www.elsevier.com/locate/molstruc
Crystal and molecular structure of the quinuclidine betaine with p-hydroxybenzoic
acid complex studied by X-ray diffraction, DFT, FTIR, and NMR methods
*
Z. Dega-Szafran , A. Katrusiak, M. Szafran
Faculty of Chemistry, Adam Mickiewicz University, ul. Grunwadzka 6, 60-780 Poznan´, Poland
a r t i c l e i n f o
a b s t r a c t
Article history:
Quinuclidine betaine (1-carboxymethyl-1-azabicyclo[2.2.2]octane inner salt, QNB) forms a complex with
p-hydroxybenzoic acid (HBA) at the 1:1 ratio. The crystals are triclinic, space group P1, with two symme-
ꢀ
Received 1 December 2009
Accepted 22 December 2009
Available online 29 December 2009
try non-equivalent QNBÁHBA complexes linked by a sequence of four O–HÁÁÁO hydrogen bonds into a zig-
zag chain. Both oxygen atoms of the carboxylate groups of two QNB are linked with two HBA molecules
through the COOÁÁÁHOOC hydrogen bonds of 2.561(2), and 2.556(2) Å, and the COOÁÁÁHO hydrogen bonds
of 2.609(2) and 2.687(2) Å. A trio ABC band at ca. 2800, 2550, 1910 cmÀ1 observed in the FTIR spectrum is
characteristic of a medium-strong hydrogen bond in carboxylic acids. The second-derivative IR spectrum
confirms the presence of two non-equivalent C@O and two COO groups. The molecular structures of the
1:1 and 2:2 complexes have been optimized by the B3LYP/6-31G(d,p) approach. The experimental and
predicted, by GIAO/B3LYP/6-31G(d,p), 1H and 13C chemical shifts correlate linearly.
Keywords:
Quinuclidine betaine
4-Hydroxybenzoic acid
Hydrogen bonds
X-ray diffraction
DFT calculations
Spectroscopic studies
Ó 2009 Elsevier B.V. All rights reserved.
1. Introduction
2. Experimental
p-Hydroxybenzoic acid crystallizes as monohydrate in mono-
clinic space group P21/a [1–3]. A pair of acid molecules is linked
through the hydrogen bonds (2.678 Å) between carboxyl groups
to form a dimer. The dimers are further hydrogen bonded between
phenolic hydroxyl groups and water molecules. p-Hydroxybenzoic
acid has been isolated from Cinnamomum osmophloeum leaves and
identified by X-ray diffraction [4]. p-Hydroxybenzoic acid has two
different proton-donor groups, COOH (pKa1 = 4.67) and OH
(pKa2 = 9.37) [5]. The effect of substituent on the pKa values of
substituted benzoic acid has been examined using the DFT (density
functional theory) calculations [6].
Quinuclidine betaine (1-carboxymethyl-1-azabicyclo[2.2.2]-
octane inner salt, QNB) was prepared as described previously in
Ref. [15]. The complex of QNB with the commercial p-hydroxy-
benzoic acid (HBA) was obtained by mixing the equimolar
amounts of QNB and HBA in methanol. The solvent was evaporated
and the solid product was precipitated upon addition of diethyl
ether. The crystals were grown from an acetonitrile–methanol
mixture (6:1), m.p. 153 °C. Analysis for C16H21NO5; calcd.:%C,
62.53; %H, 6.69; %N, 4.56; found:%C, 62,48; %H, 6.79; %N, 4.36.
The deuterated complex was prepared by threefold crystallization
from D2O.
Recently, we have studied the effect of the hydroxyl group in
benzoic acids, as an additional proton-donor group, in complexes
with zwitterionic compounds, e.g. betaines [7–14]. The present pa-
per is a continuation of that project. We have now extended our
study on preparation and determination the structure of the com-
plex of quinuclidine betaine (1-carboxymethyl-1-azabicy-
clo[2.2.2]octane inner salt, QNB) with p-hydroxybenzoic acid,
HBA (Fig. 1), as well as on the structures optimized at the B3LYP/
6-31G(d,p) level of theory and spectroscopic studies of this novel
chemical compound.
The crystal structure of QNBÁHBA was determined by X-ray dif-
fraction, measured with a KUMA KM-4 CCD diffractometer [16,17].
The structure was solved by direct methods using SHELXS-97 [18]
and refined on F2 by full-matrix least-squares with the SHELXL-97
[19]. The numbering of atoms is shown in Fig. 2. The crystal data,
details of data collection and structure refinement are given in
Table 1, and the final atomic coordinates are listed in Table 2.
The complete set of structural parameters in CIF format is available
as an Electronic Supplementary Publication from the Cambridge
Crystallographic Data Centre (CCDC 755370).
The DFT calculations were performed with the GAUSSIAN-03
program package [20]. The calculations employed the B3LYP ex-
change-correlation functional, which combines the hybrid ex-
change functional of Becke [21,22] with the gradient-correlation
functional of Lee, Yang and Parr [23] and the split-valence polar-
ized 6-31G(d,p) basis set [24]. The magnetic isotropic shielding
* Corresponding author. Tel.: +48 61 8291216; fax: +48 61 8291505.
E-mail address: degasz@amu.edu.pl (Z. Dega-Szafran).
0022-2860/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.molstruc.2009.12.043

Z. Dega-Szafran et al. / Journal of Molecular Structure 967 (2010) 80–88
81
of 2 cmÀ1. The FTIR spectra were recorded in Nujol and Fluorolube
suspensions using KBr plates. Each spectrum consisted of 64 scans.
The NMR spectra were recorded on a Varian Gemini 300 VT
spectrometer operating at 300.07 and 75.46 MHz for 1H and 13C,
respectively. The spectra were measured in DMSO-d6 relative to
internal standard of TMS.
m
o
β
α
_
+
p
i
...HOOC
γ
N
CH2COO
OH
Fig. 1. Molecular structure of the 1:1 complex of quinuclidine betaine with p-
hydroxybenzoic acid.
3. Results and discussion
Table 1
Crystal data and structure refinement for the complex of quinuclidine betaine with p-
hydroxybenzoic acid (1).
3.1. Crystal structure
Empirical formula
Formula weight
Temperature
Wavelength
Crystal system
Space group
C32H42N2O10
614.68
The complex of quinuclidine betaine (QNB) with p-hydroxyben-
zoic acid (HBA) are formed at the 1:1 ratio and its structure (1) has
been determined by X-ray diffraction. The crystals of 1 are triclinic,
293(2) K
1.54184 Å
Triclinic
ꢀ
space group P1. The structure with the atomic labels is shown in
ꢀ
P1
Fig. 2. Bond lengths, bond and torsion angles are given in Table 3.
The complex 1 is built of two symmetry independent pairs of
QNBÁHBA (Figs. 2 and 3). Both oxygen atoms of the carboxylate
group of each QNB moieties are involved in two hydrogen bonds
with the COOH and OH groups of two neighboring HBA molecules
(Fig. 3). The sequence of two COOHÁÁÁOOC and O–HÁÁÁOOC hydrogen
bonds links the molecules into a chain extending along the crystal
direction [1 1 0]. The shorter O–HÁÁÁO hydrogen bonds, as expected,
are formed between the COOH groups of HBA and COOÀ groups of
QNB: O(3)–HÁÁÁO(1) and O(8)–HÁÁÁO(6) of 2.591(2) and 2.556(2) Å,
respectively. The hydroxyl group of the HBA molecules, as a weak-
er proton-donor, forms longer hydrogen bonds with QNB; O(10)–
HÁÁÁO(2) of 2.609(2) Å and O(5)–HÁÁÁO(7)a of 2.687(2) Å [aSymmetry
code: x À 1, y À 1, z) (Table 4). Similar arrangements of the mole-
cules (betaines and HBA) were observed in the 1:1 complex of N-
methylmorpholine betaine (MMB) with HBA [7] and in the com-
plex of pyridine betaine with HBA [14], however, in the latter com-
plex the COOHÁÁÁOOC and OHÁÁÁOOC hydrogen bonds are almost of
the same length, 2.645(3) and 2.643(3) Å. The opposite situation
has been observed in the complex of N-methylpiperidine betaine
(MPB) with HBA, where the OHÁÁÁOOC hydrogen bond is slightly
shorter of 2.617(1) Å than the COOHÁÁÁOOC bond of 2.622(1) Å,
and two molecular pair of the MPBÁHBA complexes are combined
into a centrosymmetric dimer [8].
Unit cell dimensions
a
b
c
a
10.8266(4) Å
12.1538(5) Å
12.8039(5) Å
74.270(4)°
b
c
71.337(4)°
77.574(4)°
Volume
Z
Calculated density
Absorption coefficient
F(0 0 0)
1521.12(11) Å3
4
1.342 g/cm3
0.827 mmÀ1
656
Crystal size
0.3 Â 0.2 Â 0.1 mm
h range for data collection
Max/min. indices h, k, l
Reflections collected/unique
hMax(°)/completeness (%)
Absorption correction
Refinement method
Data/restraints/parameters
Goodness-of-fit on F2
Final R1/wR2 indices [I > 2rI
R1/wR2 indices (all data)
Largest diff. peak and hole
3.73–76.14°
À13/12, À15/15, À10/16
11210/6095 [Rint = 0.0120]
76.14/95.8
None
Full-matrix least-squares on F2
6095/0/565
1.022
]
0.0452/0.1181
0.0472/0.1197
0.302 and À0.213 e ÅÀ3
tensors were calculated with the standard GIAO/B3LYP/6-31G(d,p)
(Gauge-Independent Atomic Orbital) approach using the conduc-
tor-like screening continuum solvation model (COSMO) [25].
FTIR spectrum was measured on a Bruker IFS 66v/S instrument,
evacuated to avoid water and CO2 absorptions, with the resolution
In the crystal structure of the complex investigated the
piperidinium rings in both independent QNB moieties have a
distorted-boat conformation. The same signs of torsion angles of
the N–CH2–CH2–CH bridges are characteristic of
a propeller
Fig. 2. The symmetry-independent part of the unit cell in the crystal structure of the complex of quinuclidine betaine with p-hydroxybenzoic acid. The hydrogen bonds are
indicated as the dashed lines and the atomic vibrations are visualized as ellipsoids drawn at the 50% probability level.

82
Z. Dega-Szafran et al. / Journal of Molecular Structure 967 (2010) 80–88
Table 2
Atomic coordinates (Â104) and equivalent isotropic displacement parameters (Å2 Â 103) for the complex of quinuclidine betaine with p-hydroxybenzoic acid (1). U(eq) is defined
as one third of the trace of the orthogonalized Uij tensor.
Atom
x
y
z
Ueq/Uiso
Atom
x
y
z
Ueq/Uiso
N(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
6632(1)
7408(1)
6651(2)
5274(2)
5433(4)
6293(2)
4658(2)
5358(1)
7402(2)
7722(1)
7770(1)
7949(1)
5471(1)
6278(1)
5790(1)
4485(1)
3688(1)
4174(1)
5918(1)
7205(1)
5168(1)
4033(1)
7600(16)
8170(20)
6580(30)
7120(30)
4730(20)
4590(30)
5670(30)
7160(20)
5879(18)
3630(30)
4359(12)
4848(19)
5587(19)
6870(20)
8270(20)
7178(18)
6329(19)
2802(18)
3601(17)
7390(20)
3130(20)
4701(1)
3692(1)
3337(2)
4012(2)
5255(2)
5657(1)
3769(3)
4370(2)
5158(1)
4381(1)
3315(1)
4932(1)
829(1)
2710(1)
2203(1)
1575(2)
1758(1)
1243(3)
1760(1)
3029(2)
3556(1)
3251(1)
4316(1)
4491(1)
4904(1)
7701(1)
7894(1)
8703(1)
9354(1)
9204(1)
8377(1)
6786(1)
6326(1)
6466(1)
10127(1)
2830(14)
1699(17)
1830(20)
650(30)
1401(18)
1390(30)
510(30)
1223(19)
2100(16)
3340(20)
2889(10)
3776(16)
4160(17)
3443(16)
2674(17)
7469(15)
8829(16)
9670(15)
8278(14)
5680(20)
38(1)
47(1)
68(1)
61(1)
92(1)
54(1)
83(1)
50(1)
49(1)
47(1)
56(1)
72(1)
41(1)
48(1)
53(1)
44(1)
45(1)
46(1)
44(1)
55(1)
66(1)
57(1)
49(4)
66(5)
110(9)
122(9)
79(6)
130(11)
129(11)
81(6)
64(5)
101(8)
18(3)
69(5)
66(5)
68(5)
66(5)
59(5)
69(5)
58(5)
55(4)
92(7)
88(7)
N(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(18)
C(19)
C(20)
O(6)
9209(1)
9600(2)
8395(2)
7171(2)
7355(2)
8514(2)
7023(2)
8271(1)
10449(1)
10364(1)
9267(1)
11451(1)
9047(1)
8905(1)
8757(2)
8762(1)
8948(1)
9082(1)
9183(1)
9153(1)
9302(1)
8601(1)
10140(20)
10150(20)
8480(30)
8280(30)
6400(20)
6600(30)
7500(20)
9140(20)
8220(20)
6260(20)
6880(20)
8088(17)
8768(19)
10788(16)
11049(17)
8924(17)
8677(19)
8982(18)
9220(18)
9290(20)
8430(20)
9093(1)
9356(2)
9647(2)
9457(2)
8228(2)
8033(1)
10278(2)
10109(1)
8906(1)
8524(1)
8444(1)
8300(1)
6446(1)
5328(1)
4499(1)
4772(1)
5874(1)
6697(1)
7365(1)
7021(1)
8341(1)
3937(1)
9980(20)
8630(20)
9220(20)
10500(30)
9595(18)
8110(20)
7660(20)
7410(20)
7940(19)
10118(18)
11040(20)
9928(15)
10751(17)
9655(15)
8334(15)
5130(15)
3730(18)
6006(16)
7472(17)
7660(20)
4290(20)
12903(1)
13830(1)
14768(2)
14544(1)
14404(2)
13390(2)
13450(1)
12496(1)
11976(1)
10962(1)
10879(1)
10291(1)
8205(1)
8821(1)
8336(1)
7209(1)
6573(1)
7072(1)
8705(1)
9776(1)
8170(1)
6769(1)
13459(19)
14125(18)
15480(20)
14720(20)
15172(18)
14250(20)
15120(20)
13595(18)
12710(19)
13243(18)
13570(19)
11863(15)
12244(16)
11713(14)
12314(14)
9605(16)
38(1)
56(1)
71(1)
60(1)
70(1)
55(1)
58(1)
44(1)
43(1)
41(1)
60(1)
51(1)
37(1)
45(1)
50(1)
42(1)
47(1)
46(1)
42(1)
62(1)
64(1)
62(1)
86(7)
81(6)
104(8)
117(9)
77(6)
97(8)
99(7)
78(6)
84(6)
76(6)
85(6)
59(5)
66(5)
53(4)
56(5)
57(5)
71(5)
63(5)
66(5)
88(7)
98(8)
C(9)
C(10)
O(1)
O(2)
O(7)
C(21)
C(22)
C(23)
C(24)
C(25)
C(26)
C(27)
O(3)
C(31)
C(32)
C(33)
C(34)
C(35)
C(36)
C(37)
O(8)
À219(1)
À1149(1)
À1045(1)
13(1)
929(1)
1822(1)
1740(1)
2645(1)
À1983(1)
3105(14)
3978(17)
2540(30)
3530(30)
3749(19)
5700(30)
5450(30)
5842(19)
6310(17)
3960(20)
4534(12)
5097(18)
3774(17)
5847(18)
5299(16)
À290(15)
O(4)
O(5)
O(9)
O(10)
H(12A)
H(12B)
H(13A)
H(13B)
H(14)
H(15A)
H(15B)
H(16A)
H(16B)
H(17A)
H(17B)
H(18A)
H(18B)
H(19A)
H(19B)
H(32)
H(33)
H(35)
H(36)
H(8)
H(2A)
H(2B)
H(3A)
H(3B)
H(4)
H(5A)
H(5B)
H(6A)
H(6B)
H(7A)
H(7B)
H(8A)
H(8B)
H(9A)
H(9B)
H(22)
H(23)
H(25)
H(26)
H(3)
À1883(18)
69(15)
1669(15)
2380(20)
À1860(20)
8772(17)
5800(16)
6627(16)
10082(19)
6060(20)
H(5)
10304(19)
H(10)
conformation. The average magnitudes of the angles are À9 4.3°
for N(1)–C–C–C(4) and 5.9 0.3° for N(11)–C–C–C(14) (Table 3).
However, the ethylene N(1)–C(8)–C(7)–C(4) carbons have the larg-
est thermal ellipsoids of all atoms in this structure (Fig. 2), which
clearly indicates that these atoms vibrate strongly and perpendic-
ular to the average N(1)–C–C–C(4) planes. This is connected with
the low conformational stability of the ethylene bridges, which
have low potential energy (planar conformation metastable) for
the conversion to the opposite propeller turns. The strong vibra-
tions of the N(1)–C–C–C(4) ethylene carbons are the likely reason
for the differences in these torsion-angle magnitudes. The opposite
signs of the torsion angles in the two QNB moieties indicate the
opposite sense of the propeller turns. The propeller conformation
of quinuclidine moiety was observed in quinuclidine betaine hy-
drate [15], N-(carbethoxymethyl)quinuclidinium chloride dihy-
drate [26] and in the complex of quinuclidine betaine with
tartaric acid [27]. Analogous conformational features were re-
ported for 1,4-diazabicyclo[2.2.2]octane, its H-bonded complexes
and derivatives [28–36].
The O–HÁÁÁO bonded zigzag chains interact with their neighbor-
ing chains mainly via weak C–HÁÁÁO and van der Waals contacts.
The most pronounced C–HÁÁÁO contacts involve carbonyl oxygens
of the carbonyl groups: C(6)–H(6B)ÁÁÁO(4)b of 3.279(3) Å and
C(18)–H(18B)ÁÁÁO(9)c of 3.318(3) Å [symmetry codes: b1 À x,
1 À y, 1 À z; c2 À x, 2 À y, 2 À z] (Table 4). It is characteristic that
for both the carboxyl groups the shortest C–HÁÁÁO contacts are
formed to the a-methylene hydrogens of quinuclidinium moieties
(for the atomic labeling see Fig. 1), which indicates the role of the
electrostatic attraction in these interactions [37–50].
3.2. B3LYP/6-31G(d,p) calculations
The structures of the 2:2 complex of quinuclidine betaine with
HBA (2) and two 1:1 complexes of QNBÁHBA (3 and 4) optimized at
the B3LYP/6-31G(d,p) level of theory are shown in Fig. 5. Similarly
as in the crystals, the optimized structure 2 is built of two indepen-
dent QNBÁHBA units (Table 3). The molecules are linked by the
O(3)–HÁÁÁO(1)–C(10), C(10)–O(2)ÁÁÁH–O(10) and C(37)–O(8)–HÁÁÁ
O(6)–C(20) hydrogen bonds of 2.616, 2.713 and 2.586 Å, respec-
tively (Table 4). All these calculated OÁÁÁO distances are longer than
those observed in the crystal. The propeller conformations in
both quinuclidinium fused-rings systems are also observed. The
The conformation of the HBA molecule can be described by the
dihedral angle between the plane of the aromatic rings and the car-
boxyl group, and they are 14.5(2)° and 1.3(2)°, in two symmetry-
independent molecules, respectively (Figs. 3 and 4).

Z. Dega-Szafran et al. / Journal of Molecular Structure 967 (2010) 80–88
83
Table 3
Experimental (1) and calculated (2) by the B3LYP/6-31G(d,p) level of theory bond lengths (Å), bond and selected angles (°) for the complex of quinuclidine betaine with p-
hydroxybenzoic acid.
Parameters
X-ray
B3LYP
Parameters
X-ray
B3LYP
1
2
1
2
Bond lengths
N(1)–C(2)
C(2)–C(3)
C(3)–C(4)
C(4)–C(5)
C(5)–C(6)
N(1)–C(6)
C(4)–C(7)
1.507(2)
1.527
N(11)–C(12)
C(12)–C(13)
C(13)–C(14)
C(14)–C(15)
C(15)–C(16)
N(11)–C(16)
C(14)–C(17)
C(17)–C(18)
N(11)–C(18)
N(11)–C(19)
C(19)–C(20)
C(20)–O(6)
C(20)–O(7)
C(31)–C(32)
C(32)–C(33)
C(33)–C(34)
C(34)–O(10)
C(34)–C(35)
C(35)–C(36)
C(31)–C(36)
C(31)–C(37)
C(37)–O(8)
C(37)–O(9)
1.509(2)
1.513
1.505(2)
1.518(3)
1.498(3)
1.519(3)
1.517(2)
1.520(3)
1.547(3)
1.511(2)
1.503(2)
1.529(2)
1.246(2)
1.240(2)
1.391(2)
1.379(2)
1.391(2)
1.355(2)
1.389(2)
1.377(2)
1.394(2)
1.478(2)
1.321(2)
1.213(2)
1.542
1.540
1.540
1.545
1.515
1.539
1.542
1.527
1.516
1.560
1.257
1.245
1.404
1.388
1.401
1.363
1.401
1.390
1.400
1.487
1.325
1.233
1.516(2)
1.518(3)
1.515(3)
1.521(2)
1.515(2)
1.517(2)
1.523(2)
1.509(2)
1.503(2)
1.527(2)
1.252(2)
1.241(2)
1.387(2)
1.379(2)
1.390(2)
1.350(2)
1.384(2)
1.378(2)
1.389(2)
1.483(2)
1.313(2)
1.209(2)
1.546
1.541
1.540
1.542
1.526
1.538
1.542
1.525
1.521
1.574
1.270
1.229
1.406
1.387
1.408
1.344
1.409
1.388
1.403
1.483
1.326
1.237
C(7)–C(8)
N(1)–C(8)
N(1)–C(9)
C(9)–C(10)
C(10)–O(1)
C(10)–O(2)
C(21)–C(22)
C(22)–C(23)
C(23)–C(24)
C(24)–O(5)
C(24)–C(25)
C(25)–C(26)
C(21)–C(26)
C(21)–C(27)
C(27)–O(3)
C(27)–O(4)
Bond angles
N(1)–C(2)–C(3)
C(2)–C(3)–C(4)
C(3)–C(4)–C(5)
C(4)–C(5)–C(6)
N(1)–C(6)–C(5)
C(2)–N(1)–C(6)
C(3)–C(4)–C(7)
C(5)–C(4)–C(7)
C(4)–C(7)–C(8)
N(1)–C(8)–C(7)
C(2)–N(1)–C(8)
C(6)–N(1)–C(8)
C(9)–N(1)–C(2)
C(9)–N(1)–C(6)
C(9)–N(1)–C(8)
N(1)–C(9)–C(10)
O(1)–C(10)–C(9)
O(2)–C(10)–C(9)
O(1)–C(10)–O(2)
C(21)–C(22)–C(23)
C(22)–C(23)–C(24)
C(23)–C(24)–C(25)
C(24)–C(25)–C(26)
C(25)–C(26)–C(21)
C(22)–C(21)–C(26)
C(22)–C(21)–C(27)
C(26)–C(21)–C(27)
O(3)–C(27)–C(21)
O(4)–C(27)–C(21)
O(4)–C(27)–O(3)
O(5)–C(24)–C(23)
O(5)–C(24)–C(25)
110.63(12)
110.20(13)
106.68(19)
110.70(14)
109.78(13)
107.48(10)
105.75(16)
113.6(2)
109.58
109.18
108.78
108.84
110.22
108.21
108.34
108.50
108.94
110.07
109.08
108.58
111.53
109.16
110.20
116.39
116.90
112.62
130.44
120.69
119.73
120.12
119.69
120.75
119.04
122.04
118.93
113.37
122.41
124.22
117.35
122.54
N(11)–C(12)–C(13)
C(12)–C(13)–C(14)
C(13)–C(14)–C(15)
C(14)–C(15)–C(16)
N(11)–C(16)–C(15)
C(12)–N(11)–C(16)
C(13)–C(14)–C(17)
C(15)–C(14)–C(17)
C(14)–C(17)–C(18)
N(11)–C(18)–C(17)
C(12)–N(11)–C(18)
C(16)–N(11)–C(18)
C(19)–N(11)–C(12)
C(19)–N(11)–C(16)
C(19)–N(11)–C(18)
N(11)–C(19)–C(20)
O(6)–C(20)–C(19)
O(7)–C(20)–C(19)
O(6)–C(20)–O(7)
C(31)–C(32)–C(33)
C(32)–C(33)–C(34)
C(33)–C(34)–C(35)
C(34)–C(35)–C(36)
C(35)–C(36)–C(31)
C(32)–C(31)–C(36)
C(32)–C(31)–C(37)
C(36)–C(31)–C(37)
O(8)–C(37)–C(31)
O(9)–C(37)–C(31)
O(9)–C(37)–O(8)
110.86(13)
109.63(14)
108.66(16)
110.43(13)
109.84(13)
108.34(12)
108.42(16)
108.73(15)
109.97(12)
110.23(11)
108.34(11)
109.31(11)
107.17(10)
112.28(10)
111.26(10)
118.62(10)
120.06(11)
113.68(11)
126.25(12)
121.08(12)
120.07(12)
119.42(12)
119.85(12)
121.43(12)
118.09(11)
122.51(11)
119.39(11)
113.83(11)
122.66(13)
123.51(12)
118.20(13)
122.37(13)
110.21
108.83
108.84
109.12
109.64
108.21
108.52
108.23
108.87
110.16
108.60
109.18
109.87
111.18
109.74
116.51
114.94
113.52
131.48
120.76
120.41
119.15
119.84
121.29
118.56
122.18
119.26
113.83
122.42
123.74
117.80
123.05
108.41(15)
109.65(12)
110.19(11)
108.00(11)
112.45(11)
108.15(11)
110.40(10)
117.16(11)
119.95(12)
112.46(14)
127.56(14)
120.79(13)
120.24(13)
119.41(13)
119.91(12)
121.21(13)
118.33(13)
122.80(12)
118.83(12)
114.86(11)
123.02(12)
122.11(13)
118.65(13)
121.93(12)
O(10)–C(34)–C(33)
O(10)–C(34)–C(35)
Torsion angles
N(1)–C(2)–C(3)–C(4)
C(2)–C(3)–C(4)–C(5)
C(3)–C(4)–C(5)–C(6)
C(4)–C(5)–C(6)–N(1)
C(2)–N(1)–C(6)–C(5)
C(6)–N(1)–C(2)–C(3)
C(2)–C(3)–C(4)–C(7)
C(7)–C(4)–C(5)–C(6)
C(4)–C(7)–C(8)–N(1)
C(3)–C(4)–C(7)–C(8)
C(5)–C(4)–C(7)–C(8)
C(8)–N(1)–C(2)–C(3)
C(8)–N(1)–C(6)–C(5)
C(2)–N(1)–C(8)–C(7)
À6.5(2)
63.9(2)
À57.0(3)
À4.8(3)
62.2(2)
À55.6(2)
À57.3(2)
59.1(3)
16.01
49.22
N(11)–C(12)–C(13)–C(14)
C(12)–C(13)–C(14)–C(15)
C(13)–C(14)–C(15)–C(16)
C(14)–C(15)–C(16)–N(11)
C(12)–N(11)–C(16)–C(15)
C(16)–N(11)–C(12)–C(13)
C(12)–C(13)–C(14)–C(17)
C(17)–C(14)–C(15)–C(16)
C(14)–C(17)–C(18)–N(11)
C(13)–C(14)–C(17)–C(18)
C(15)–C(14)–C(17)–C(18)
C(18)–N(11)–C(12)–C(13)
C(18)–N(11)–C(16)–C(15)
C(12)–N(11)–C(18)–C(17)
6.2(2)
55.3(2)
À62.3(2)
5.5(2)
55.7(2)
À62.9(2)
À62.7(2)
55.5(2)
6.1(2)
55.6(2)
À62.4(2)
55.6(2)
À62.2(2)
À62.6(2)
À14.07
66.69
À49.14
À16.03
69.02
À51.04
À50.95
68.65
À66.91
14.35
50.83
À68.86
À68.55
50.75
14.56
50.44
À15.6(2)
À14.19
69.7(2)
67.26
À46.9(2)
61.9(2)
À67.51
67.26
67.36
49.10
À56.7(2)
À67.45
À67.37
À49.01
À48.5(2)
À50.71
(continued on next page)

84
Z. Dega-Szafran et al. / Journal of Molecular Structure 967 (2010) 80–88
Table 3 (continued)
Parameters
X-ray
B3LYP
Parameters
X-ray
B3LYP
1
2
1
2
C(6)–N(1)–C(8)–C(7)
C(9)–N(1)–C(2)–C(3)
C(9)–N(1)–C(6)–C(5)
C(9)–N(1)–C(8)–C(7)
68.6(2)
50.36
C(16)–N(11)–C(18)–C(17)
C(19)–N(11)–C(12)–C(13)
C(19)–N(11)–C(16)–C(15)
C(19)–N(11)–C(18)–C(17)
C(12)–N(11)–C(19)–C(20)
C(16)–N(11)–C(19)–C(20)
C(18)–N(11)–C(19)–C(20)
N(11)–C(19)–C(20)–O(6)
N(11)–C(19)–C(20)–O(7)
C(31)–C(32)–C(33)–C(34)
C(32)–C(33)–C(34)–C(35)
C(33)–C(34)–C(35)–C(36)
C(34)–C(35)–C(36)–C(31)
C(36)–C(31)–C(32)–C(33)
C(32)–C(31)–C(36)–C(35)
C(32)–C(33)–C(34)–O(10)
C(36)–C(35)–C(34)–O(10)
C(37)–C(31)–C(32)–C(33)
C(37)–C(31)–C(36)–C(35)
C(32)–C(31)–C(37)–O(8)
C(36)–C(31)–C(37)–O(8)
C(32)–C(31)–C(37)–O(9)
C(36)–C(31)–C(37)–O(9)
55.3(2)
67.08
À174.5(1)
À176.2(2)
À173.4(2)
À67.9(2)
173.6(1)
55.6(2)
171.06
172.38
169.87
À68.26
172.21
53.05
175.7(2)
173.8(1)
179.9(1)
174.9(1)
56.2(2)
À172.60
À170.23
À170.83
À171.59
68.64
À52.25
À29.49
152.95
0.08
C(2)–N(1)–C(9)–C(10)
C(6)–N(1)–C(9)–C(10)
C(8)–N(1)–C(9)–C(10)
N(1)–C(9)–C(10)–O(1)
N(1)–C(9)–C(10)–O(2)
C(21)–C(22)–C(23)–C(24)
C(22)–C(23)–C(24)–C(25)
C(23)–C(24)–C(25)–C(26)
C(24)–C(25)–C(26)–C(21)
C(26)–C(21)–C(22)–C(23)
C(22)–C(21)–C(26)–C(25)
C(22)–C(23)–C(24)–O(5)
C(26)–C(25)–C(24)–O(5)
C(27)–C(21)–C(22)–C(23)
C(27)–C(21)–C(26)–C(25)
C(22)–C(21)–C(27)–O(3)
C(26)–C(21)–C(27)–O(3)
C(22)–C(21)–C(27)–O(4)
C(26)–C(21)–C(27)–O(4)
À66.8(2)
24.6(2)
27.12
4.6(2)
À157.5(1)
À155.02
À174.3(1)
0.7(2)
À1.2(2)
0.08
À1.8(2)
À0.04
À0.05
0.08
À0.05
À0.03
179.98
179.94
179.90
À179.98
0.37
1.5(2)
À0.01
3.3(2)
À2.2(2)
À0.08
–1.8(2)
2.7(2)
À1.2(2)
0.6(2)
0.11
À2.2(2)
1.6(2)
À0.06
À0.04
178.9(1)
À177.4(1)
À175.1(1)
176.7(1)
–14.3(2)
168.0(1)
164.8(1)
À12.9(2)
À179.4(1)
178.8(1)
178.9(1)
À179.5(1)
À0.2(2)
À179.1(1)
À179.7(1)
1.8(2)
À179.90
179.80
179.69
À179.79
2.01
À179.68
À179.37
0.58
À178.25
À178.19
1.55
Fig. 3. The hydrogen-bonded chain of the molecules of the complex of quinuclidine betaine with p-hydroxybenzoic acid running along the crystal direction [1 1 0] (cf. Fig. 2).
The aggregate can be perceived in 3 dimensions as an autostereogram [64].
Table 4
magnitude of the N–CH2–CH2–C(4) torsion angles is similar in both
rings, and are ca. 14° (Table 3). In the optimized structure 3 QNB is
Experimental and calculated, at the B3LYP/6-31G(d,p) approach, hydrogen bonds
dimensions, for the complex of quinuclidine betaine with p-hydroxybenzoic acid (Å
linked with HBA by the COOÁÁÁHOOC hydrogen bond of 2.539 Å,
and °).
while in the structure 4 the hydroxyl group of HBA interacts with
No.
D–HÁÁÁA
X-ray
d(D–H)
d(HÁÁÁA)
d(DÁÁÁA)
<(DHA)
the carboxylate group of QNB and the OÁÁÁO distance is 2.664 Å.
The calculated energies and dipole moments for 2, 3, 4, QNB and
HBA determined by the B3LYP/6-31G(d,p) level of theory are listed
in Table 5. Morokuma and coworkers [51–53] defined energy sta-
bilization as a difference between the energy of the global system
1
O(3)–H(3)ÁÁÁO(1)
O(10)–H(10)ÁÁÁO(2)
O(8)–H(8)ÁÁÁO(6)
O(5)–H(5)ÁÁÁO(7)a
C(6)–H(6)ÁÁÁO(4)b
C(18)–H(18)ÁÁÁO(9)c
0.93(2)
0.95(3)
1.04(2)
0.92(2)
0.96(3)
0.98(3)
1.668(21)
1.664(24)
1.540(23)
1.794(22)
2.37(3)
2.591(2)
2.609(2)
2.556(2)
2.687(2)
3.279(3)
3.318(3)
172(3)
174(3)
163(3)
165 (3)
158(2)
155(3)
and the total energy of the separate partners:
D
E = ECOMPLEX
À
2.40(3)
ECOMPONENTS. The estimated binding energy ( E) of the QNB mole-
D
cule by HBA are listed in Table 5, and it increases in order 2 > 3 > 4,
as expected.
B3LYP/6-31G(d,p)
O(3)–H(3)ÁÁÁO(1)
O(10)–H(10)ÁÁÁO(2)
O(8)–H(8)ÁÁÁO(6)
O(3)–H(3)ÁÁÁO(1)
O(10)–H(10)ÁÁÁO(2)
2
1.003
0.990
1.011
1.619
1.725
1.582
2.616
2.713
2.586
172.43
175.89
171.80
3.3. Infrared spectra
3
4
1.026
0.998
1.519
1.669
2.539
2.664
172.35
174.16
The solid-state FTIR spectrum of the crystalline QNBÁHBA com-
Symmetry code: ax À 1, y À 1, z; b1 À x, 1 À y, 1 À x; c2 À x, 2 À y, 2 À z.
plex is shown in Fig. 6. According to the crystal structure (Table 4)

Z. Dega-Szafran et al. / Journal of Molecular Structure 967 (2010) 80–88
85
Fig. 4. The molecular arrangement of H-bonded aggregates in the complex of quinuclidine betaine with p-hydroxybenzoic acid viewed down the [0 0 1] direction.
Fig. 5. The structure of complexes of quinuclidine betaine with p-hydroxybenzoic acid optimized at the B3LYP/6-31G(d.p) level of theory at the ratio 2:2 (2) and 1:1 (3 and 4).
there are two moderate O–HÁÁÁO hydrogen bonds in the complex
the range of 1750–1550 cmÀ1, which confirm the presence of
two non-equivalent QNBÁHBA complexes (Fig. 7). The strong band
investigated. As a consequence, the
mOH absorption appears in
the 3200–1800 cmÀ1 region. The contour of this absorption is
known as the ABC bands, which are observed in the spectra of
Table 5
hydrogen-bonded carboxylic acid. The
A
(ꢀ2800 cmÀ1),
B
Calculated energies (E, HF, a.u.), dipole moments (l, D) and binding energies (DE,
kcal/mol) at B3LYP/6-31G(d,p) approach for the complexes of quinuclidine betaine
(QNB) with p-hydroxybenzoic acid (HBA).
(ꢀ2500 cmÀ1) and C (ꢀ1900 cmÀ1) bands arise from the Fermi res-
onance of the mOH with 2dOH and 2cOH [54–56]. This trio of bands is
Compounda
E
D
E
l
observed in the spectrum of the complex investigated (Fig. 6). Deu-
terium substitution affects all three bands. Band A and B disappear
and new bands appear at 2300 and 2000 cmÀ1, while band C from
1900 cmÀ1 shifts to 1635 cmÀ1 and overlaps the carbonyl band.
2
3
4
QNB
HBA
À2106.5579485
À1053.2676116
À1053.2652737
À557.1767069
À496.0578548
À34.98
À20.73
À19.23
22.37
10.81
17.68
11.57
1.85
The bands at 1680 and 1600 cmÀ1 are attributed to the
m
C@O
asCOO vibrations of HBA and QNB moieties, respectively.
The second-derivative spectrum [57,58] shows several minima in
and
m
a
See Fig. 5.

86
Z. Dega-Szafran et al. / Journal of Molecular Structure 967 (2010) 80–88
2.0
1.5
1.0
0.5
0.0
3600
3000
2400
1800
1500
1200
900
600
Wavenumbers (cm-1)
Fig. 6. The solid-state FTIR spectrum in Nujol and Fluorolube emulsions of the quinuclidine betaine – p-hydroxybenzoic acid complex; dashed line of the spectrum of the
deuterated sample.
0.1
0.0
at 1270 cmÀ1 is assigned to the
msCOO mode (Fig. 6). The bands at
1.5
1.0
0.5
0.0
1584, 1470 and 1250 cmÀ1 are due to the bending in-plane OH
modes (dOH) of hydrogen bonds, which are shifted to 1350 and
1010 cmÀ1 in the spectrum of the deuterated sample. The bands
at 779, 614 and 451 cmÀ1 are assigned to the bending out-of-plane
b
a
OH modes (cOH), however, only one band assigned to the cOD is
observed at 599 cmÀ1 in the spectrum of deuterated sample, the
others appear below 400 cmÀ1 and are not detected.
3.4. NMR studies
-0.1
Both the 1H and 13C NMR spectra (Fig. 8) in DMSO-d6 show that
the investigated complex exists as 1:1 species. The proton and car-
bon-13 chemical shifts are listed in Table 6. The carbon atoms at-
1750
1700
1650
1600
1550
1500
Wavenumbers ( cm-1)
tached to the quaternary nitrogen atom are denoted as
a, the
Fig. 7. Infrared spectra of the complex of quinuclidine betaine with p-hydroxy-
benzoic acid: (a) solid line the FTIR spectrum in Fluorolube emulsions and (b)
dashed line the second-derivative FTIR spectrum in the 1750–1500 cmÀ1 region.
others as b and
c
(Fig. 1). The 1H NMR spectrum is simple, similar
to those of other quinuclidinium betaine derivatives [15,26,27,59].
CH2
α
β
(a)
γ
m
o
7.80 7.60 7.40 7.20 7.00 6.80
3.8 3.6 3.4 3.2 3.0 2.8 2.6 2.4 2.2 2.0 1.8 1.6
β
o
(b)
m
p
α
COO
CH2
γ
i
COOH
70
60
50
40
30
20
170 160 150 140 130 120
Chemical shifts (ppm)
Fig. 8. 1H (a) and 13C (b) NMR spectra of the complex of quinuclidine betaine with p-hydroxybenzoic acid in DMSO-d6.

Z. Dega-Szafran et al. / Journal of Molecular Structure 967 (2010) 80–88
87
Table 6
Experimental (dexp, in DMSO-d6) and predicted (dpred, in vacuum and DMSO) proton and carbon-13 chemical shifts (ppm), and calculated magnetic isotropic shielding tensors (
r)
by the GIAO/B3LYP/6-31G(d,p) calculations for complex 3 of quinuclidine betaine with p-hydroxybenzoic acid.
Atoma
dexp
dpred
r
dpred
r
DMSO-d6
DMSO
DMSO
Vacuum
Vacuum
1H
H-
H-b
H-
a
3.63
1.90
2.03
3.51
7.78
6.86
3.68
1.87
2.17
3.09
2.04
6.83
27.8833 1.1792
29.7131 0.0553
29.4041
28.4737 0.0868
23.4701 0.0255
24.6920 0.0387
31.2492
3.97
2.00
2.04
2.84
8.13
6.51
27.7472 2.0648
29.7482 0.4709
29.7136
28.8985 0.0999
23.5058 0.1186
25.1603 0.2710
31.2115
c
N+–CH2
H-ortho
H-meta
ab
bb
r
À0.9888
À0.9818
0.9913
0.9778
13C
C-
C-b
C-
a
53.44
23.47
19.29
64.37
164.81
131.45
115.21
162.00
121.34
167.33
54.50
22.77
19.67
64.39
164.81
131.50
112.42
160.75
122.52
168.69
136.0652 2.7109
165.7150 0.1320
168.6166
126.8244
32.9946
64.1156 0.3257
81.9524 0.0774
36.7882
72.5145
29.3699
53.94
22.12
20.02
66.42
156.93
132.51
111.20
159.48
126.03
170.34
136.1032 2.2096
165.3555 0.9098
167.2874
124.6234
41.4046
63.8646 0.5491
83.4499 1.1343
39.0593
69.8160
29.0775
c
N+–CH2
COO
C-ortho
C-meta
C-para
C-ipso
COOH
ab
200.1221
201.9644
bb
r
À1.0702
À1.0876
0.9996
0.9987
a
For atoms numbering see Fig. 1.
Coefficients for the equation: dexp = a + b
b
r.
8
6
4
150
100
50
b
2
a
22
24
26
28
30
50
100
150
Magnetic isotropic shielding tensors (ppm)
Fig. 9. Plots of the experimental 1H (a) and 13C (b) chemical shifts (in DMSO-d6) versus the magnetic isotropic shielding tensors from the GIAO/B3LYP/6-31G(d,p) calculations
for the complex of quinuclidine betaine with p-hydroxybenzoic acid; s in vacuum,
D
in DMSO solution (the correlation line is given for values in the DMSO solution).
The average values of the magnetic isotropic shielding tensors (r),
4. Conclusions
calculated by the GIAO/B3LYP/6-31G(p,d) approach for the 1:1
complex of QNBÁHBA (3) in vacuum and in the DMSO solution,
are given in Table 6. The linear relations between the experimental
chemical shifts and the magnetic isotropic shielding tensors are
Two symmetry-independent molecules of the complex of
quinuclidine betaine (QNB) with p-hydroxybenzoic acid (HBA)
are linked into chain, by a sequence of O–HÁÁÁO hydrogen bonds.
Both carboxylate oxygen atoms of each QNB molecule are involved
in the hydrogen bonds with COOH (2.591(2), 2.556(2) Å) and OH
(2.609(2), 2.687(2) Å) groups of two neighboring HBA molecules.
These medium-strong hydrogen bonds result a trio ABC bands in
the 2800–1900 cmÀ1 region in the IR spectra characteristic of the
hydrogen-bonded carboxylic acids. The calculated magnetic isotro-
described by the following equation: dexp = a + b
r [60–62] and
shown in Fig. 9. The correlation coefficients (r) show that these
relationships are better for carbon than for protons (Table 6). The
protons are located on the peripheries of the molecules and thus
are supposed to be more susceptible to intermolecular (solvent–
solute) effects than carbons [63]. The a and b coefficients are used
to calculate the predicted 1H and 13C chemical shifts (dpred) (Ta-
ble 6). The agreement between the experimental and predicted
1H and 13C chemical shifts is better in the DMSO solution than in
vacuum.
pic shielding tensors (
r
) correlate linearly with the experimental
1H and 13C chemical shifts (dexp = a + b
r), which confirms correct
assignments of the chemical shifts. The optimized structure of
the 1:1 complex of QNBÁÁÁHOOC–C6H4OH (3) is by 1.47 kcal/mol

88
Z. Dega-Szafran et al. / Journal of Molecular Structure 967 (2010) 80–88
Challacombe, P.M.W. Gill, B. Johnson, W. Chen, M.W. Wong, C. Gonzalez, J.A.
Pople, GAUSSIAN 03, Revision D.02, Gaussian, Inc., Wallingford CT, 2004.
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more stable than that of the complex QNBÁÁÁHO–C6H4COOH (4). The
binding energies, E, for the optimized structure 2, 3 and 4 confirm
that the 2:2 complex of QNB with HBA is a more stable then the 1:1
D
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