Comprehensive experimental investigation of mechanically induced 1,4-diazines synthesis in solid state

Article abstract of DOI:10.1016/j.tet.2017.03.014

Compared mechanosynthesis of two condensed 1,4-diazines were investigated in ball milling conditions from o-phenylenediamine. ¹³C CP-MAS NMR revealed a hemiaminal intermediate for dibenzo[a,c]phenazine synthesis accumulated under mechanical act

Full text of DOI:10.1016/j.tet.2017.03.014

Accepted Manuscript
Comprehensive experimental investigation of mechanically induced 1,4-diazines
synthesis in solid state
Paulo F.M. Oliveira, Naoki Haruta, Alain Chamayou, Brigitte Guidetti, Michel Baltas,
Kazuyoshi Tanaka, Tohru Sato, Michel Baron
PII:
S0040-4020(17)30239-9
10.1016/j.tet.2017.03.014
TET 28520
DOI:
Reference:
To appear in: Tetrahedron
Received Date: 2 March 2017
Accepted Date: 6 March 2017
Please cite this article as: Oliveira PFM, Haruta N, Chamayou A, Guidetti B, Baltas M, Tanaka K, Sato T,
Baron M, Comprehensive experimental investigation of mechanically induced 1,4-diazines synthesis in
solid state, Tetrahedron (2017), doi: 10.1016/j.tet.2017.03.014.
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to
our customers we are providing this early version of the manuscript. The manuscript will undergo
copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please
note that during the production process errors may be discovered which could affect the content, and all
legal disclaimers that apply to the journal pertain.

ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
Comprehensive experimental investigation of mechanically induced 1,4-
diazines synthesis in solid state
Paulo F. M. Oliveira,a,b,*,† Naoki Haruta,c,† Alain Chamayou,a Brigitte Guidetti,b Michel
Baltas,b,* Kazuyoshi Tanaka,c Tohru Sato,c,d Michel Barona*
a
Centre RAPSODEE, CNRS UMR 5302, Université de Toulouse, Mines-Albi, Campus
Jarlard, 81013 Albi, France.
b
Laboratoire SPCMIB, CNRS UMR 5068, Université de Toulouse, UPS, 118 Route de
Narbonne, 31062 Toulouse, France.
c
Department of Molecular Engineering, Graduate School of Engineering, Kyoto University,
Nishikyo-ku, Kyoto 615-8510, Japan.
d
Unit of Elements Strategy Initiative for Catalysts & Batteries, Kyoto University, Nishikyo-
ku, Kyoto 615-8510, Japan.
*
Corresponding authors: pmarques@mines-albi.fr (P. F. M. Oliveira); baltas@chimie.ups-tlse.fr (M. Baltas);
baron@mines-albi.fr (M. Baron), tel +33 (0)5 6349 3063.
†
present addresses: (P. F. M. Oliveira) Université de Lille, UMET, Unité Matériaux et Transformations, CNRS
UMR 8207, F-59 000 Lille, France.
(N. Haruta) Hybrid Materials Unit, Institute of Innovative Research, Tokyo Institute of Technology, S2-6, 4259
Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
1

ACCEPTED MANUSCRIPT
Abstract. Compared mechanosynthesis of two condensed 1,4-diazines were investigated in
13
ball milling conditions from o-phenylenediamine. C CP-MAS NMR revealed a hemiaminal
intermediate for dibenzo[a,c]phenazine synthesis accumulated under mechanical action, as
confirmed by calorimetry. Such intermediate, which is not detected in the case of 2,3-
diphenylquinoxaline synthesis, provides experimental evidence of a concerted reaction
between highly reactive mechanically-excited diamine and 9,10-phenanthrenequinone.
Keywords: mechanochemistry, ball milling, reaction intermediates, reaction mechanism,
diazines
2

ACCEPTED MANUSCRIPT
1. Introduction
1,4-Diazines such as phenazines and quinoxalines are an important class of nitrogen
heterocyclic compounds with interesting applications in chemistry and materials science.1,2
These scaffolds are also commonly found in biologically active structures and drug
pharmacophores.3–6 Phenazines and quinoxalines derivatives have been classically
synthesized in solution media, but more recently, alternative ways such as mechanochemistry
have been used to prepare diazines.7–9
Mechanochemistry has been highlighted as an efficient route to prepare different
classes of chemicals.10–14 Organic mechanosyntheses often proceed rapidly, in solvent-free
conditions with high yields10,15,16 and selectivity17,18 and can originate unexpected reaction
pathways.19 Neat or liquid-assisted grinding of powders showed also to afford either known or
novel products that cannot be prepared otherwise.20–24 Although the macromechanisms of
such transformations have been extensively described,11b,14,25–29 the consequences of
mechanical stresses on atomic and electronic levels remain to be further investigated. The
mechanical stresses can deform the molecules in the crystal lattice and certain bonds,
inducing orbital deformation,30,31 “inverse Jahn-Teller effect” and HOMO-LUMO gap
closure,31–33 minimizing the activation barriers for reactions. The solid properties are also
responsible to promote or hamper product formation.16,34
The reaction between o-phenylenediamine (1) and 9,10-phenanthrenequinone (2a)
under ball milling conditions yielding dibenzo[a,c]phenazine (3a) (Scheme 1) was previously
investigated by the group.8 The experimental results indicated the reaction continuation after
the milling and a possible push-pull stepwise mechanism was proposed for this post-grinding
period.8b Vibronic coupling density and Density Functional Theory (DFT) calculations were
used to elucidate the mechanisms and energetic barriers of this same reaction.35 A concerted
mechanism for addition of diamine 1 to the dione 2a was considered to be possible under
continuous mechanical excitation while this level of energy is not reasonably achieved by
thermal activation.35 More recently, the ball milling reaction between 1 and benzil (2b) to
yield 2,3-diphenylquinoxaline (3b) (Scheme 1) was studied.9 It was observed a possible
reduction of the activation energy caused by the mechanical energy at lower temperatures,
3

ACCEPTED MANUSCRIPT
whereas a liquid phase occurred when milling at higher temperature, concomitant with an
activation energy similar to the one of a thermal reaction.9
Based on the previous results of the group on mechanosynthesis of condensed 1,4-
diazines 3a and 3b,8,9,35 and in continuation of our efforts to get a comprehensive mechanistic
insight, we wish to report here our recent investigations of these reactions concerning the
conditions favoring a concerted or a stepwise mechanism under mechanical milling. In that
aim, the kinetic behavior at room temperature was determined while calorimetry and 13C CP-
MAS NMR techniques were also used.
2. Results and Discussion
The mechanosyntheses of 1,4-diazines were carried out by co-milling solid o-
phenylenediamine (1), and 1,2-diones; 9,10-phenanthrenequinone (2a) and benzil (2b) to
yield, respectively, dibenzo[a,c]phenazine (3a) and 2,3-diphenylquinoxaline (3b) (Scheme 1).
Scheme 1. Mechanosynthesis of condensed 1,4-diazines (3a and 3b) from the reaction
between solids 1,2-diamine 1 and 1,2-diones 2a and 2b.
The differences on the overall kinetics of transformation for 3a and 3b syntheses,
followed by HPLC (Fig. 1), suggested different reaction mechanisms. While for 3b the
reaction reaches completion in 60 min, a fourfold increase of continuous milling is necessary
to produce 3a quantitatively. This was attributed to the higher electrophilic character and
4

ACCEPTED MANUSCRIPT
chemical reactivity of C=O group of 2b compared to that of 2a36 and to solid state
constrains,16,34 such as H-bonding, reactive site exposure, and flexibility of 2b compared to
the flat rigid molecule 2a. The formation of compound 3b follows an apparent zero-order
reaction type9 (Fig. 1, red line), whereas that of 3a approaches a sigmoidal. This can include
not only chemical reactions, but also physicochemical aspects such as diffusional limitations,
nuclei formation and growth behavior. This latter could represent the overall kinetics of 3a
synthesis, thus suggesting that once several nuclei are created during the first 60 min, the first
crystallites of product formed act as templates increasing the reaction rate. The effect of
seeding was previously reported for other mechanically induced reactions in ball mill.37,38
Figure 1. Kinetics of transformation for condensed 1,4-diazines mechanosynthesis.
13C CP-MAS NMR spectra were recorded for both reactions in the course of the
13
milling period. For 3a, C CP-MAS NMR spectra evidenced a C-OH signal at δ=81.0 ppm
(Fig. 2a), representing a signature of a hemiaminal intermediate generated upon consumption
of 1 and 2a and evolving progressively towards the aromatic product 3a. It is noteworthy to
point out that this intermediate was not detected during the 3b synthesis (Fig. 2b).
It is also interesting to point the splitting of the C=O signal observed for compound 2a
in Fig. 2a (δ=180.0 and 175.5 ppm), that can be attributed to environmental effects of the
solid state.39,40 The crystalline 2a has two crystallographic distinct molecules in the
asymmetric unit cell, whatever the polymorphic form.41,42 This gives two chemical shifts in
the solid-state NMR spectra for a chemically equivalent entity.39,40 In the case of 2b, half the
molecule composes the asymmetric unit with the symmetric axis across the C-C center
5

ACCEPTED MANUSCRIPT
bond.43,44 As consequence, one signal in 13C CP-MAS NMR is assigned to the C=O (δ=195.0
ppm).45,46
In figure 2a, the C=O signals of 2a decrease similarly as the duration of the milling
increases. The molecules of 2a must be detached from the crystal lattice by reacting with 1 to
yield the C-OH hemiaminal intermediate. Contrary to the starting material, the intermediate is
not able to crystallize easily and orderly and presents a single 13C NMR shift. All the signals
from the diamine 1 also decrease clearly in the course of the reaction, and after 240 min, the
13C CP-MAS NMR is identical to pure 3a obtained by recrystallization from ethanol (Fig. 2,
green spectrum)
(a)
6

ACCEPTED MANUSCRIPT
(b)
13
Figure 2. C CP-MAS NMR spectra of mechanosynthesis at different milling times: (a) 3a
and (b) 3b synthesis
Under continuous milling, no intermediate bearing both a C=O and a C=N group,
indicating a stepwise mechanism, was detected. Actually, the 13C resonance of the C=N of
this intermediate is expected around δ=160 ppm.47–50 On the other hand, DFT calculations and
vibronic coupling density theory previously demonstrated the theoretical possibility of a
concerted mechanism for 3a mechanosynthesis.35 This scenario is corroborated by NMR (Fig.
2a), with both carbonyl groups transformed into hemiaminal by direct concerted addition,
giving the intermediate AB (Fig. 3a) under application of mechanical energy. The unusual
7

ACCEPTED MANUSCRIPT
stability of AB can be attributed to the fact that the water elimination in this rigid molecule is
disfavored in the absence of solvent.
Figure 3. (a) The AB intermediate bearing the C-OH hemiaminal. (b) The excited form of 1
at the center: 1* (Reproduced from Ref. 35).
Such concerted addition needs both amino groups located fleetingly on the same sides
of the aromatic nucleus.35 However, the amino groups of 1 are located on opposite sides of the
aromatic plane,51 giving the crystal structure stability by hydrogen bonds. But, the huge
amount of energy supplied to the powder by mechanical action,52 disintegrates the crystal and
provides the short-lived activated form of 1,35 1* (Fig. 3b), reacting with 2a according to a
concerted mechanism, generating the cis-bis-hemiaminal AB intermediate. On the other hand,
the probability for 1* to react with the cis conformer of 2b is much lower, since the cis
conformation of this 1,2-dione is disfavored.9 Furthermore, the flexibility of 2b enables faster
reaction towards 3b formation as shown by kinetic monitoring and 13C CP-MAS NMR for the
milling period records (Fig. 2b).
An interesting observation for both 3a and 3b mechanosynthesis is the reaction
continuation in the powder when the grinding is interrupted. No further reaction occurs if
13
dissolved. The reaction monitoring by C CP-MAS NMR after a milling period for 3a (30
min) and 3b (15 min) synthesis (see Fig. S1 in Supplementary Data) showed progressive
disappearance of AB, previously formed and accumulated during the milling period for the
case of 3a, while for 3b no intermediate was detected.
In order to further investigate the thermodynamics of the reaction, calorimetric
measurements were carried out isothermally at 25 °C with the reactant powder mixture in the
post-milling period and showed different patterns of heat flow curves for each case (Fig. 4). In
8

ACCEPTED MANUSCRIPT
the case of 3a mechanosynthesis, the curves (Fig. 4a) have the highest heat flow at the
beginning that decays rapidly, followed by a slower decrease. On the other hand, for 3b, the
heat flow decays constantly from the beginning during the first 12 h (Fig. 4b), indicating a
different behavior for 3a. In this later case, considering the accumulation of AB under
continuous mechanical stress, it induces the release of a large amount of heat resulting in that
peak of heat flow.
Figure 4. Heat released by the reactant solid mixture for the following 24 h after milling: (a)
3a synthesis and (b) 3b synthesis.
Table 1. Heat released by the reactant solid mixture during the calorimetric measurements
3a
3b
Ha
(kJ ∆mol2a
t
(min)
5
Overall
∆
H
∆
Hb
∆
Hc
(kJ ∆mol3b )
t
(min)
15
Overall
∆
H
∆
-1
-1
-1
(J)
)
(J)
(kJ ∆mol2b
)
-551.76 ± 11.95
-616.02 ± 11.32
-630.23 ± 2.25
-456.92
-147.56 ± 3.20
-155.97± 2.86
-181.35 ± 0.65
-233.27
-364.84 ± 31.95 -111.18 ± 9.74
-238.39 ± 26.64 -86.52 ± 9.67
-111.19 ± 9.74
-106.49 ± 11.90
-104.32 ± 7.88
-
30
15
60
30
-120.68 ± 9.11
-20.62
-130.37 ± 9.93
-
90d
120
60d
PMe
-313.00 ± 4.96
-263.39 ± 4.17
-187.68
-232.35 ± 9.24
-88.19 ± 3.55
-88.53 ± 3.56
150d -146.37
heat released per mol of: a 2a and b 2b consumed during
analysis and c 3b formed
180
-75.85 ± 1.74
-145.17± 3.33
- 148.53
dsingle determination; ePM=physical mixture
240d -38.62
PMe
-120.79 ± 3.11
-77.52 ± 3.01
9

ACCEPTED MANUSCRIPT
Table 1 displays the integrations values of the curves (Fig. 4) for 24 h of monitoring.
Such enthalpies incorporate contributions from all processes including reaction enthalpy and
product crystallization. However, the heat of crystallization at 25 °C can be neglected. For
example, in the extreme case in which all the powder would undergo a crystallization towards
the final crystalline product; the overall heat released would not exceed 2.5 J or 3a at this
temperature.53 Furthermore, a critical amount of product should be present to start the
nucleation and growth processes. In the case of 3b, the estimated heat of crystallization at 25
°C is about 53.7 J; but the kinetics of transformation is also higher and thus, crystallization
already occurs prior to analysis.
The values of heat released per mol of 2a consumed during the measurements are not
constant for all milling times, confirming that the energy released does not come exclusively
from the reaction between 1 and 2a to form 3a. If so, the values should tend to that of
physical mixture (-77.52 kJ ∆mol2a-1, for a reaction extent of 25 %) that is mostly originated
from the heat of reaction itself.
Thus, considering that, part of 1 and 2a is consumed during the milling period,
although 3a is not formed yet, larger amount of AB is accumulated under mechanical action,
thus releasing more heat towards 3a formation during the calorimetric runs when compared to
overall reaction, from pure 1 + 2a affording 3a (Scheme 2).
Scheme 2. The accumulated AB intermediate releases more heat than the overall reaction
starting from 1 and 2a.
Unlike the values from Table 1 for 3a, the values of heat released per mol of 2b
consumed or 3b formed (Table 1) are statistically equivalent. Comparing these values at
different milling times for 3b formation, with the value of heat released by the physical
10

ACCEPTED MANUSCRIPT
mixture (PM, Table 1) of 1 and 2b they can be predominantly due to the heat of reaction
despite the exothermic effect of crystallization. The heat released related to reaction extent
indicates clearly that there was in this case no accumulation of activated species of higher
level of energy during the milling process.
The results of calorimetry are also valuable in understanding mechanistic
mechanochemistry. First, pure milled reagents 1, 2a and 2b did not show any thermic event,
indicating that the heat released from the runs with a mixture of reactants is not a consequence
of temperature increase during milling. Second, the high heat released, even for shorter
milling times such as 5-15 min, indicates that co-milling of the raw materials is more efficient
to induce reaction than the physical mixture of very fine reactant powders (milled during 30
min prior to mixing), thus demonstrating the critical role of mechanical energy in addition to
particle breakage, mixing and surface renewal. It must be noted that the heat released by the
physical mixtures is associated to the huge defective surface area generated by the pre-
milling, increasing the free energy and facilitating reactions on the interfaces.14c,49 HPLC
detected only traces of reaction from the mixture of the non-milled reactants.
3. Conclusion
In summary, this study allowed in-depth knowledge of 3a synthesis through the experimental
evidence of a hemiaminal intermediate formed under mechanochemical conditions and
13
highlighted by C CP-MAS NMR, leading to the exothermic formation of 3a. The primary
contribution of calorimetry, first used here for this purpose, equally emphasized the high
energetic level obtained under milling. The comparison with 3b synthesis was important to
demonstrate that this intermediate can be generated and accumulated upon solvent-free
application of mechanical stress. The mechanical action showed to be able to induce
transformations other than ones in solution directly from excited states, unstable in solvated
media, but that reacts with 2a by a concerted mechanism. The results also value the
mechanochemistry as a means to overcome solvated media limitations by enabling generation
and trapping of reactive intermediates. Owing the susceptibility of evidencing very original
mechanisms that appear within divided solids undergoing mechanical stresses, experimental
and computational investigations, linking the consequences of mechanical energy from
11

ACCEPTED MANUSCRIPT
powders and down to the atomic scale, are essential for further progress in the field of
mechanochemistry and the future formalization of its rules.
4. Experimental
4.1.General procedure for 3a and 3b condensed 1,4-diazines synthesis
For a typical experiment, 2 g of powder composed of stoichiometric amounts of 1,2-diamine
and 1,2-dione, without previous mechanical treatment, were placed in the bowl of a vibratory
ball-mill (Pulverisette 0, Fritsch) with a single ball at the equilibrium temperature for milling
(25 °C). The amplitude was adjusted at 2 mm (for further details concerning the milling
device, see ref. 28). Equimolar amounts of o-phenylenediamine (1, 0.6698 g) and 9,10-
phenanthrenequinone (2a, 1.3204 g) were used for dibenzo[a,c]phenazine (3a) synthesis, and
1 (0.6793 g) and benzil (2b, 1.3207 g) for 2,3-diphenylquinoxaline (3b) synthesis. The
grinding system, bowl + ball, was to equilibrate at the required temperature (25°C) for at least
12 h prior to each run. The total weight of the powder of 2 g was used for all experiments.
4.2. Dibenzo[a,c]phenazine (3a). mp: 224-226 °C 1H NMR (300 MHz, CDCl3) δ ppm: 7.68 –
7.83 (m, 4H), 7.87 (dd, 2H, J = 6.6, 3.4 Hz), 8.36 (dd, 2H, J = 6.5, 3.4 Hz), 8.54 (dd, 2H, J =
13
7.7, 1.7 Hz), 9.41 (dd, 2H, J = 7.9, 1.7 Hz). C NMR (75 MHz, CDCl3) δ ppm: 122.89 (s,
2C), 126.32 (s, 2C), 127.94 (s, 2C), 129.30 (s, 2C), 129.86 (s, 2C), 129.99 (s, 2C), 130.39 (s,
2C), 132.03 (s, 2C), 141.94 (s, 2C, C=N), 142.27 (s, 2C). HRMS (ESI, TOF) m/z: C20H13N2
(calc./found) 281.1079/281.1081 [M+H+].
4.3. 2,3-diphenylquinoxaline (3b). mp: 125-127 °C. 1H NMR (300 MHz, CDCl3) δ ppm: 7.30
– 7.46 (m, 6H), 7.47 – 7.62 (m, 4H,), 7.80 (dd, 2H, J = 6.4, 3.4 Hz,), 8.21 (dd, 2H, J = 6.4, 3.4
Hz). 13C NMR (75 MHz, CCl3-d) δ ppm: 128.27 (s, 4C), 128.81(s, 2C), 129.20 (s, 4C), 129.85
(s, 2C), 129.97 (s, 2C), 139.07 (s, 2C), 141.22 (s, 2C), 153.47 (s, 2C, C=N). HRMS (ESI,
TOF) m/z: C20H15N2 (calc./found) 283.1235/283.1237 [M+H+].
Acknowledgments
The authors acknowledge CNRS/JSPS France-Japan joint research project (n° PRC0709,
2013–2014) and the French Embassy in Japan (Exploration 2017) for financial support,
Séverine Patry for help in calorimetry and Yannick Coppel for NMR experiments.
12

ACCEPTED MANUSCRIPT
Appendix A. Supplementary Data
Supplementary data contains experimental details of characterization and analytical
13
techniques used as well as the description of the methodologies. C CP-MAS NMR spectra
for post-milling period are also presented.
References
1.
2.
3.
Achelle S, Baudequin C, Plé N. Dye Pigment. 2013;98:575–600.
Kaim W. Angew Chemie Int Ed. 1983;22:171–90.
Pereira J a, Pessoa AM, Cordeiro MNDS, Fernandes R, Prudêncio C, Noronha JP, et al.
Eur J Med Chem. 2015;97:664–72.
4.
5.
6.
7.
8.
Dolezal M, Zitko J. Expert Opin Ther Pat. 2015;25:33–47.
González M, Cerecetto H. Expert Opin Ther Pat. 2012;22:1289–302.
Laursen JB, Nielsen J. Chem Rev. 2004;104:1663–86.
Kaupp G, Naimi-Jamal MR. European J Org Chem. 2002;2002:1368–73.
(a) Carlier L, Baron M, Chamayou A, Couarraze G. Tetrahedron Lett. 2011;52:4686–9.
(b) Carlier L, Baron M, Chamayou A, Couarraze G. Powder Technol. 2013;240:41-47.
9.
Oliveira PFM, Baron M, Chamayou A, Baltas M, Guidetti B, Haruta N, et al.
ChemistrySelect. 2016;1:984–8.
10. (a) James SL, Adams CJ, Bolm C, Braga D, Collier P, Friščić T, et al. Chem Soc Rev.
2012;41:413–47. (b) Ranu B, Stolle A, editors. Ball Milling Towards Green Synthesis:
Applications, Projects, Challenges. Cambridge: Royal Society of Chemistry; 2014. (c)
Wang G-W. Chem Soc Rev. 2013;42:7668–700. (d) Hernández JG, Friščić T.
Tetrahedron Lett. 2015;56:4253–65. (e) Declerck V, Nun P, Martinez J, Lamaty F.
Angew Chemie Int Ed. 2009;48:9318–21.
11. Braga D, Maini L, Grepioni F. Chem Soc Rev. 2013;42:7638.
12. Friščić T. Metal-Organic Frameworks: Mechanochemical Synthesis Strategies. Encycl.
Inorg. Bioinorg. Chem., Chichester, UK: John Wiley & Sons, Ltd; 2014, p. 1–19.
13

ACCEPTED MANUSCRIPT
13. (a) Boldyrev V V. Russ Chem Rev. 2006;75:177–89. (b) Boldyreva E. Chem Soc Rev.
2013;42:7719–38.
14. (a) Descamps M, Willart JF. Adv Drug Deliv Rev. 2016;100:51–66. (b) Willart JF,
Descamps M. Mol Pharm. 2008;5:905–20. (c) Descamps M, Willart JF, Dudognon E,
Caron V. J Pharm Sci. 2007;96:1398–407.
15. Kaupp G. CrystEngComm. 2006;8:794–804.
16. Oliveira PFM, Baron M, Chamayou a., André-Barrès C, Guidetti B, Baltas M. RSC
Adv. 2014;4:56736–42.
17. Rodríguez B, Bruckmann A, Bolm C. Chem - A Eur J. 2007;13:4710–22.
18. Cravotto G, Garella D, Carnaroglio D, Gaudino EC, Rosati O. Chem Commun.
2012;48:11632.
19. (a) Hickenboth CR, Moore JS, White SR, Sottos NR, Baudry J, Wilson SR. Nature.
2007;446:423–7. (b) Wollenhaupt M, Krupička M, Marx D. ChemPhysChem.
2015;16:1593–7. (c) 1. Li J, Nagamani C, Moore JS. Acc Chem Res. 2015;48:2181–90.
(d) Friedrichs J, LüßMann M, Frank I. ChemPhysChem. 2010;11:3339–42.
20. Zefirov NS, Sereda GA, Volkov VP, Tkachenko SE, Zyk N V. Chem Heterocycl
Compd. 1996;32:577–9.
21. (a) Michalchuk AAL, Tumanov IA, Drebushchak VA, Boldyreva E V. Faraday
Discuss. 2014;170:311–35. (b) Michalchuk AAL, Tumanov IA, Boldyreva E V.
CrystEngComm. 2013;15:6403–12.
̈
22. Tan D, Mottillo C, Katsenis AD, Štrukil V, Friščic T. Angew Chemie - Int Ed.
2014;53:9321–4.
23. Friščić T, Fábián L. CrystEngComm. 2009;11:743–5.
24. Štrukil V, Gracin D, Magdysyuk O V., Dinnebier RE, Friščić T. Angew Chemie Int Ed.
2015;54:8440–3.
25. Kuroda R, Higashiguchi K, Hasebe S, Imai Y. CrystEngComm. 2004;6:463.
26. Kaupp G, Naimi-Jamal MR. CrystEngComm. 2005;7:402.
14

ACCEPTED MANUSCRIPT
27. Kaupp G. CrystEngComm. 2003;5:117.
28. Rothenberg G, Downie a. P, Raston CL, Scott JL. J Am Chem Soc. 2001;123:8701–8.
29. Chadwick K, Davey R, Cross W. CrystEngComm. 2007;9:732.
30. (a) Luty T, Ordon P, Eckhardt CJ. J Chem Phys. 2002;117:1775. (b) Luty T, Eckhardt
CJ. J Am Chem Soc. 1995;117:2441–52.
31. Gilman JJ. Science (80- ). 1996;274:65–0.
32. (a) Senna M. J Mater Sci. 2004;39:4995–5001. (b) Pradipta M, Watanabe H, Senna M.
Solid State Ionics. 2004;172:169–72.
33. Kuklja MM, Stefanovich E V., Kunz a. B. J Chem Phys. 2000;112:3417.
34. Gavezzotti A, Simonetta M. Chem Rev. 1982;82:1–13.
35. Haruta N, Sato T, Tanaka K, Baron M. Tetrahedron Lett. 2013;54:5920–3.
36. Muddasir H, Lu P, Gu C, Wang Z, Yang S, Yang B, et al. Chem Res Chinese Univ.
2009;25 (6):950–6.
37. Trotzki R, Hoffmann MM, Ondruschka B. Green Chem. 2008;10:767.
38. Trotzki R, Hoffmann MM, Ondruschka B. Green Chem. 2008;10:873–8.
39. Middleton DA, Le Duff CS, Berst F, Reid DG. J Pharm Sci. 1997;86:1400–2.
40. Middleton DA, Patching SG. Solid-State NMR Spectroscopy in Drug Design and
Discovery. Stereoselective Synth. Drugs Nat. Prod., Hoboken, NJ, USA: John Wiley &
Sons, Inc.; 2013, p. 1–20.
41. Matsuzaki SY, Gotoh M, Kuboyama A. Mol Cryst Liq Cryst. 1987;142:127–39.
42. Rae AD, Willis AC. Zeitschrift Fur Krist. 2003;218:221–30.
43. Brown CJ, Sadanaga R. Acta Crystallogr. 1965;18:158–64.
44. More M, Odou G, Lefebvre J. Acta Crystallogr Sect B Struct Sci. 1987;43:398–405.
45. Chippendale AM, Mathias A, Aujla RS, Harris RK, Packer KJ, Say BJ. J Chem Soc
Perkin Trans 2. 1983:1357.
15

ACCEPTED MANUSCRIPT
46. Rezler M, Zołek T, Wolska I, Maciejewska D. Acta Crystallogr Sect B Struct Sci Cryst
Eng Mater. 2014;70:820–7.
47. Cherkasov VK, Druzhkov NO, Kocherova TN, Shavyrin AS, Fukin GK. Tetrahedron.
2012;68:1422–6.
48. Anitha P, Manikandan R, Viswanathamurthi P. J Coord Chem. 2015;68:3537–50.
49. Afrasiabi Z, Sinn E, Lin W, Ma Y, Campana C, Padhye S. J Inorg Biochem.
2005;99:1526–31.
50. Anitha P, Manikandan R, Endo A, Hashimoto T, Viswanathamurthi P. Spectrochim
Acta - Part A Mol Biomol Spectrosc. 2012;99:174–80.
51. Czapik A, Gdaniec M. Acta Crystallogr Sect C Cryst Struct Commun. 2010;66:o198–
201.
52. Delogu F. Mater Chem Phys. 2012;137:297–302.
53. This value is the heat of crystallization at 25 °C. I was estimated from the the heat of
fusion/heat of crystallization at melting temperature. Based on: Willart J-F, Carpentier
L, Danède F, Descamps M. J Pharm Sci. 2012;101:1570–7.
54.
(a) Navrotsky A, Mazeina L, Majzlan J. Science (80- ). 2008;319:1635–8. (b) Fecht
HJ. Nature. 1992;356:133–5.
16