Crystal packing of ammonium salts of arylenebis(phenylphosphinic) acids

Article abstract of DOI:10.1007/s11172-014-0411-3

It was shown for the first time that the crystal packing mode of the ammonium salt of thiophene-2,5-diylbis(phenylphosphinic acid) substantially differs from that of the dimethylammonium salt of 1,4- phenylenebis(phenylphosphinic acid). The former crystal packing is a three-layer supramolecular sandwich structure consisting of two anionic layers separated by a layer of ammonium cations, whereas the supramolecular organization of the latter salt is based on alternating layers of anions and cations linked by hydrogen bonds.

Full text of DOI:10.1007/s11172-014-0411-3

1
82
Russian Chemical Bulletin, International Edition, Vol. 63, No. 1, pp. 182—186, January, 2014
Crystal packing of ammonium salts of arylenebis(phenylphosphinic) acids*
A. V. Krayushkina, A. I. Tufatullin, O. N. Kataeva, V. A. Milyukov, and O. G. Sinyashin
A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Center of the Russian Academy of Sciences,
8
ul. Akad. Arbuzova, 420088 Kazan, Russian Federation.
Fax: +7 (843) 273 9344. Eꢀmail: krayushkina@iopc.ru
It was shown for the first time that the crystal packing mode of the ammonium salt of
thiopheneꢀ2,5ꢀdiylbis(phenylphosphinic acid) substantially differs from that of the dimethylꢀ
ammonium salt of 1,4ꢀphenylenebis(phenylphosphinic acid). The former crystal packing is
a threeꢀlayer supramolecular sandwich structure consisting of two anionic layers separated by
a layer of ammonium cations, whereas the supramolecular organization of the latter salt is
based on alternating layers of anions and cations linked by hydrogen bonds.
Key words: crystal engineering, supramolecular packing, Xꢀray diffraction study, phosꢀ
phorus acids, ammonium salts.
The crystal engineering is a priority area of modern
However, the scope of the application of phosphorus
diꢀ and polyacids in this area is not fully understood. Deꢀ
spite a considerable progress in studies of the structures
and properties of ammonium salts of a number of phosꢀ
phonic acids, such as benzylidenebisphosphonic acid,
chemistry that is of high importance for the design of
1
functional materials. One of the basic principles of the
construction of complex supramolecular systems is the
molecular recognition of discrete molecules assembled to
form highly ordered supramolecular architectures via varꢀ
1
2
1,4ꢀphenylenebis(methylidene)tetrakis(phosphonic) acid,
2
13
ious intermolecular interactions. In this case, hydrogen
and phosphonopropionic acid, ammonium derivatives
of diphosphinic acids are virtually unknown, although the
latter are characterized by the unique possibility of fine
tuning the hydrophilic/hydrophobic balance.
bonds are of special importance because they are responsiꢀ
ble for an additional binding in the crystal structures givꢀ
ing rise to supramolecular assemblies which can have difꢀ
ferent dimensionality, that is, they can be oneꢀ, twoꢀ, or
threeꢀdimensional (1D, 2D, or 3D, respectively). Hydroꢀ
gen bonds are of particular importance for the construcꢀ
tion of metalꢀorganic coordination polymers (soꢀcalled
metalꢀorganic frameworks, MOF) in which the metal
centers serve as units and are covalently linked to each
other to form a particular substructure. The presence of
hydrogen bonds is usually responsible for the formation of
a porous structure of MOF, thus making them practically
important.3
In the present study, we report the synthesis of new
arylenebis(phenylphosphinic acids) and the structures of
ammonium salts on their basis.
Results and Discussion
Arylenebis(phenylphosphinic acids) were synthesized
according to the method based on instability of the P—N
bond in phosphorus acid amides to hydrolysis.
Thus, thiopheneꢀ2,5ꢀdiylbis(phenylphosphonous acid)
diamide 1 undergoes hydrolysis to form acid 2 in a yield of
about 63%. The slow diffusion of ammonia into a solution
of acid 2 afforded crystals of salt 3 in quantitative yield
,4
Hence, the investigation of the structures of ammoniꢀ
um salts of organic acids is the first step toward the deterꢀ
mination of the scope of the application of such systems
for the construction of MOF and provides a deeper underꢀ
standing of their structural potential, thus assisting in deꢀ
(
Scheme 1).
The similar reaction proceeding through amide 4 and
acid 5 gave the dimethylammonium salt of 1,4ꢀphenꢀ
ylenebis(phenylphosphinic acid) (6) (Scheme 2).
The supramolecular structure of these ammonium
salts is determined by the main two factors: the nearly
free rotation of phosphinate groups around P—C bonds
5
signing new materials. In addition, ammonium salts of
organic and heteroorganic acids are of great interest for
the design of practically important materials, such as proꢀ
6,7
tonꢀconductive membranes, hydrogen extraction devicꢀ
es, ,9 and highly sensitive sensors.10,11
8
(
an aromatic bridging moiety) in anions and the ability of
*
Dedicated to Academician of the Russian Academy of Sciences
the ammonium cation to form hydrogen bonds. It should
be noted that these factors are interrelated. The supraꢀ
A. I. Konovalov on the occasion of his 80th birthday.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 0182—0186, January, 2014.
066ꢀ5285/14/6301ꢀ0182 © 2014 Springer Science+Business Media, Inc.
1

Crystal packing of ammonium salts
Russ.Chem.Bull., Int.Ed., Vol. 63, No. 1, January, 2014
183
Scheme 1
i. 1) BuLi/TMEDA, 2) ClP(O)(NEt )Ph; ii. HCl/H O; iii. NH .
2
2
3
Scheme 2
i. 1) BuLi/TMEDA, 2) ClP(O)(NEt )Ph; ii. HCl/H O; iii. Me NH.
2
2
2
molecular structure of salt 3 is stabilized by the formation
of intermolecular hydrogen bonds between the phosphiꢀ
nate moieties and the ammonium cations involving all
four hydrogen atoms of the cations. Apparently, it is
the presence of the unsubstituted ammonium cation that
determines the conformation of the anion in the crystal.
The phosphinate groups in the anion are located on
one side of the thiophene group (Fig. 1). This orientaꢀ
tion facilitates the formation of numerous hydrogen
bonds between the cations and anions. Thus, each oxygen
atom of the phosphinate group forms a bifurcated hydroꢀ
gen bond with two ammonium cations which are, in turn,
linked to the adjacent anion. Therefore, in the crystal,
salt 3 forms a threeꢀlayer supramolecular sandwich strucꢀ
ture consisting of two anionic layers separated by a layꢀ
er of ammonium cations (Fig. 2). Adjacent anionic layers
form a hydrophobic region with interpenetrating phenꢀ
yl groups.
The supramolecular structure of salt 6 is radically difꢀ
ferent due apparently to the ability of the dimethylammoꢀ
nium cation to form only two hydrogen bonds, as opposed
to the ammonium cation of salt 3. The dimethylammoniꢀ
um cation links two phosphinate anions via hydrogen
bonds and the anions, in turn, form hydrogen bonds with
the cations involving all oxygen atoms. The structure of
the anion in salt 6 fundamentally differs (see Fig. 1) from
that in the crystal of compound 3. Thus, the phosphinate
groups are on the opposite sides of the benzene ring. Thereꢀ
fore, the anions serve as bridges between the layers conꢀ
sisting of cations and the supramolecular organization is
based on alternating layers of anions and cations linked by
hydrogen bonds (Fig. 3).
Therefore, the supramolecular organization of the amꢀ
monium salts of bisphosphinic acids provides evidence
that the ability of anions and cations to form hydrogen
bonds between each other and the conformational lability
a
b
N
O
S
P
P
O
P
P
N
N
O
N
O
O
O
N
N
O
N
N
N
N
N
Fig. 1. Structure and hydrogen bonding in the crystals of salts 3 (a) and 6 (b).

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84
Russ.Chem.Bull., Int.Ed., Vol. 63, No. 1, January, 2014
Krayushkina et al.
Fig. 2. Fragment of the crystal packing of salt 3.
Fig. 3. Fragment of the crystal packing of salt 6.

Crystal packing of ammonium salts
Russ.Chem.Bull., Int.Ed., Vol. 63, No. 1, January, 2014
185
play a key role in these structures. The tetrahedral enviꢀ
ronment of the nitrogen atoms of the ammonium cations
dictates the directionality of intermolecular interactions,
whereas the number of hydrogen atoms in cations deterꢀ
mines the number of intermolecular hydrogen bonds. It
would be expected that such supramolecular organization
can be observed for coordination compounds of bisphosꢀ
phinic acids with metal ions which are prone to form
complexes with a tetrahedral environment.
Synthesis of thiopheneꢀ2,5ꢀdiylbis(phenylphosphinic acid) (2).
Tetramethylethylenediamine (TMEDA) (20 mL, 15.97 g,
32 mmol) was added to a solution of thiophene (4.75 mL, 5 g,
0 mmol) in petroleum ether (150 mL) under an inert atmoꢀ
sphere. Then a 1.6 M nꢀbutyllithium solution in hexane (82.51 mL,
31 mmol) was added dropwise under stirring. The reaction mixꢀ
1
6
1
ture was heated to 50 C and kept at this temperature under
stirring for 2 h. Then the reaction mixture was cooled to –78 C,
one—two drops of 15ꢀcrownꢀ5 were added, and PhP(O)Cl(NEt2)
(28.34 g, 132 mmol) was added dropwise under stirring. Then
the reaction mixture was gradually heated to room temperature
and kept under stirring for 5 h. The resulting mixture was filtered
and concentrated to a small volume. A solution of concentrated
hydrochloric acid (25.3 mL, 291 mmol) in water (40 mL) was
added under stirring to the precipitate. The reaction mixture was
heated to 40 C and kept at this temperature under stirring for
1 h. The precipitate that formed was filtered off. After the comꢀ
plete drying of the precipitate, thiopheneꢀ2,5ꢀdiylbis(phenꢀ
ylphosphinic acid) (2) was obtained in a yield of 13.78 g (63%) as
Experimental
All solvents were distilled over Na in the presence of benzoꢀ
phenone immediately before use. Methanol and ethanol of anaꢀ
lytical grade were used as is without additional purification. The
1
31
13
H (400 MHz), P (161.975 MHz), and C (100.6 MHz) NMR
spectra were recorded on a Bruker MSLꢀ400 instrument using
1
13
a white powder with the melting point of 193 C. 1H NMR
Me Si as the internal standard ( H and C) and 85% H PO as
the external standard ( P) for 10% solutions in deuterated solꢀ
vents (CDCl , DMSOꢀd ). The IR spectra were measured on
a Bruker Vectorꢀ22 FTIR spectrometer in the 400—4000 cm
region at a 4 cm–1 optical resolution in KBr pellets. The comꢀ
4
3
4
31
3
(DMSOꢀd ), : 7.53 (m, 6 H, mꢀ, pꢀPh); 7.58 (d, 2 H, J
=
6
P,H
3
= 6.67 Hz, C H S); 7.79 (ddd, 4 H, oꢀPh, J
= 12.72 Hz,
= 8.12 Hz). P NMR (DMSOꢀd ),
H,H 6
3
6
4
2
P,H
–
1
3
4
31
JH,H = 12.52 Hz, J
: 15.77. IR (KBr): 3432, 3071, 3018, 2996, 2983, 2923, 2852, 2622,
2588, 2518, 2458, 2141, 1965, 1669, 1596, 1569, 1498, 1439,
1333, 1309, 1294, 1274, 1217, 1181, 1132, 1098, 1039, 1001,
965, 833, 751, 720, 688, 576, 547, 494, 456. Found (%): C, 52.65;
H, 3.97; P, 16.89; S, 8.56. C H O P S. Calculated (%): C, 52.75;
pound PhP(O)(Cl)(NEt ) was synthesized according to a known
2
procedure.14 The elemental analysis was carried out on a highꢀ
temperature Eurovector EuroEA3028ꢀHTꢀOM CHNSꢀO eleꢀ
mental analyzer.
16
14
4 2
Xꢀray diffraction study. The Xꢀray diffraction data were colꢀ
lected at 150(2) K on a Bruker AXS Smart APEX diffractometer
using MoꢀK ( = 0.71073 Å; crystals of compound 3) and Cuꢀ
K radiation ( = 0.154184 Å; crystals of compound 6). The
H, 3.85; P, 17.03; S, 8.79.
Synthesis of diammonium thiopheneꢀ2,5ꢀdiylbis(phenylphosꢀ
phinate) (3). Single crystals of salt 3 suitable for Xꢀray diffraction
were obtained by the diffusion method. Liquid ammonia (0.3 mL)
was added to a solution of thiopheneꢀ2,5ꢀdiylbis(phenylphosꢀ
phinic acid) (0.03 g, 0.08 mmol) in THF (5 mL), and the mixꢀ
ture was allowed to stay for the slow diffusion. Transparent
needleꢀlike crystals formed on the walls of the tube in one day.
The weight of the dry product was 0.033 g. The yield was 89%.
Found (%): C, 48.03; H, 5.24; N, 6.50; P, 15.99; S, 8.06.
C H N O P S. Calculated (%): C, 48.24; H, 5.03; N, 7.04;
1
5
following programs were used: APEX2 (Xꢀray data collection),
1
6
SAINT (data processing), SADABS version 2.10 (absorpꢀ
tion correction),17 and SHELXS97 (structure solution).18 The
structures were refined by the leastꢀsquares method using the
SHELXLꢀ971 and WINGXꢀ97 programs. The figures were
8
19
2
0
generated using the ORTEPꢀ3 and Mercury CSD 2.0 proꢀ
grams.21
16
20
2
4 2
All nonhydrogen atoms for both structures were refined
anisotropically. The hydrogen atoms were positioned geometriꢀ
cally and refined using a riding model, except for the hydrogen
atoms of the ammonium cations which were located in differꢀ
ence Fourier maps and refined isotropically.
P, 15.58; S, 8.04.
Synthesis of 1,4ꢀphenylenebis(phenylphosphinic acid) (5).
A 1.6 M nꢀbutyllithium solution in hexane (57.5 mL, 92 mmol,
5.91 g) was added dropwise under stirring under an inert atmoꢀ
sphere to a solution of 1,4ꢀdibromobenzene (10 g, 42 mmol) in
THF (150 mL) cooled to –78 C. The reaction mixture was kept
at this temperature under stirring for 4 h. Then one—two drops
of 15ꢀcrownꢀ5 were added, and a solution of PhP(O)Cl(NEt2)
(19.82 g, 92 mmol) in THF (25 mL) was added dropwise under
stirring. Then the reaction mixture was gradually heated under
stirring to room temperature and concentrated to a small volꢀ
ume. The precipitate that formed was filtered off. A solution of
concentrated hydrochloric acid (16.0 mL, 184 mmol) in water
(20 mL) was added under stirring to the filtrate. The reaction
mixture was heated to 50 C and kept at this temperature under
stirring for 1 h. The resulting precipitate was filtered off. After
the complete drying of the precipitate, 1,4ꢀphenylenebis(phenꢀ
ylphosphinic acid) was obtained in a yield of 9.15 g (61%) as
Crystals of compound 3. Molecular formula C H N O P S,
1
6
20
2
4 2
3
crystals dimensions 0.23×0.2×0.11 mm , M = 398.34, monoꢀ
clinic, space group P2 /c, a = 13.095(3) Å, b = 13.885(4) Å,
1
3
c = 10.902(3) Å,  =  = 90.00,  = 100.925(4), V = 1946.3(9) Å ,
Z = 4, calc = 1.359 g cm–3,  = 0.353 mm , max = 28, 23280
–1
measured reflections, 4699 unique reflections (Rint = 0.0751),
3
257 observed reflections (I > 2(I)), 258 refined parameters,
R = 0.0441, wR = 0.0934 (I > 2(I)); residual electron density
1
2
–
3
(
max/min): 0.365/–0.349 e Å , GOOF = 1.013.
Crystals of compound 6. Molecular formula C H N O P ,
2
2
30
2
4 2
3
crystals dimensions 0.31×0.25×0.13 mm , M = 448.42, monoꢀ
clinic, space group P2 /n, a = 8.5720(10) Å, b = 6.5800(10) Å,
1
3
c = 21.451(2) Å,  =  = 90.00,  = 99.357(6), V = 1193.8(3) Å ,
Z = 2, calc = 1.247 g cm–3,  = 1.896 mm , max = 63, 17796
–1
a white powder with the melting point of 330 C. H NMR
1
3
3
measured reflections, 1851 unique reflections (Rint = 0.2224),
(DMSOꢀd ), : 7.47 (dd, 4 H, mꢀH , J
= 7.40 Hz, J
= 6.96 Hz); 7.72 (dd, 4 H,
H,H
=
6
Ph
H,H
H,H
3
1
482 observed reflections (I > 2(I)), 152 refined parameters,
= 2.63 Hz); 7.51 (d, 2 H, pꢀH , J
Ph
3
oꢀH , J
Ph
JH,P = 9.08 Hz, J
3
R = 0.0893, wR = 0.2166 (I > 2(I)); residual electron density
= 11.77 Hz, J
= 6.93 Hz); 7.80 (dd, 4 H, C H ,
= 5.66 Hz). P NMR (DMSOꢀd ), :
H,H 6
1
2
H,P
H,H
6 4
–
3
3
3
31
(
max/min): 0.401/–0.903 e Å , GOOF = 1.019.

1
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Russ.Chem.Bull., Int.Ed., Vol. 63, No. 1, January, 2014
Krayushkina et al.
2
2
1
4
2.44. IR (KBr): 3434, 3058, 3026, 2962, 2929, 2855, 2606, 2266,
162, 1685, 1593, 1486, 1438, 1384, 1338, 1314, 1262, 1193,
161, 1135, 1071, 1023, 1001, 950, 826, 750, 718, 692, 587, 553,
87, 438. Found (%): C, 59.99; H, 4.57; P, 17.01. C H O P .
8. A. B. Yaroslavtsev, Russ. Chem. Rev. (Engl. Transl.), 1994,
63 [Usp. Khim., 1994, 63, 449].
9. R. L. Kerr, S. A. Miller, R. K. Shoemaker, B. J. Elliott,
D. L. Gin, J. Am. Chem. Soc., 2009, 131, 15972.
10. P. D. van der Wal, N. F. de Rooij, M. KoudelkaꢀHep, Senꢀ
sors and Actuators B: Chemical, 1996, 35, 119.
18
16
4 2
Calculated (%): C, 60.34; H, 4.47; P, 17.32.
Synthesis of bis(dimethylammonium) 1,4ꢀphenylenebis(phenꢀ
ylphosphinate) (6). Single crystals of C H N O P suitable for
Xꢀray diffraction were obtained by the diffusion method. An
aqueous solution of dimethylamine was added to a solution of
11. C. V. Krishnamohan Sharma, C. B. Bauer, R. D. Rogersb,
M. J. Zaworotko, Chem. Commun., 1997, 16, 1559.
12. M. Plabst, N. Stock, T. Bein, Crystal Growth and Design,
2009, 9, 5049.
2
2
30
2
4 2
1
,4ꢀphenylenebis(phenylphosphinic acid) (5) (0.03 g, 0.08 mmol)
in a mixture of THF (4 mL) and water (1 mL), and the reaction
mixture was allowed to stay for the slow diffusion. The weight
of dry transparent needleꢀlike crystals was 0.029 g. The yield
was 87%. Found (%): C, 58.03; H, 6.97; N, 6.14; P, 13.89.
C H N O P . Calculated (%): C, 58.93; H, 6.70; N, 6.25;
13. K. F. Bowes, G. Ferguson, A. J. Loughc, Ch. Glidewell, Acta
Crystallogr. Sect. B, 2003, 59, 248.
14. G. S. Quin, S. Jankowksi, L. D. Quin, Phosphorus, Sulfur
Silicon Relat. Elem., 1996, 115, 93.
15. Bruker, APEX2, Software Suite for Crystallographic Programs,
Bruker AXS, Inc., Madison, WI (USA), 2009.
2
2
30
2
4 2
P, 13.84.
1
1
6. Bruker, Area Detector Control and Integration Software. Verꢀ
sion 5.x, in SMART and SAINT, Bruker Analytical Xꢀray
Instruments Inc., Madison, Wisconsin (USA), 1996.
7. G. M. Sheldrick, SHELXꢀ97, Programs for Crystal Structure
Analysis, University of Göttingen, Institut für Anorganische
Chemie der Universität, Göttingen, 1997.
8. G. M. Sheldrick, Acta Crystallogr. Sect. A, 2008, 64, 112.
9. L. J. Farrugia, J. Appl. Crystallogr., 1999, 32, 837.
0. L. J. Farrugia, J. Appl. Crystallogr., 1997, 30, 565.
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Received December 6, 2013;
in revised form December 20, 2013