polymorphs and solvates Single and double H-bonded anion ... · 1 Single and double H-bonded...

1

Single and double H-bonded anion-anion complexes in fentanyl citrate polymorphs and solvates

Rafael Barbas,a Rafel Prohens,*,a,b Antonio Bauzá,c Antonio Franconetti,c and Antonio Frontera*,c

aUnitat de Polimorfisme i Calorimetria, Centres Científics i Tecnològics, Universitat de Barcelona, Baldiri Reixac 10, 08028 Barcelona, Spain. E-mail: [email protected].

bCenter for Intelligent Research in Crystal Engineering S.L. Spain

cDepartament de Química, Universitat de les Illes Balears, Crta. de Valldemossa km 7.5, 07122 Palma (Baleares), Spain. E-mail: [email protected].

Electronic Supplementary Information

Table of contents:

1. Theoretical methods.…………………………………………….……………………………..2

2. Figure S1.…………………………......……………………………………………………………..2

3. Cartesian Coordinates..............................................................................4

4. Experimental methods...……………………………………….……………………………..5

5. Crystal data and structure refinement..………………………………………………..7

6. Characterization of solids forms.….…………………………………………………….11

7. References..............................................................................................18

Electronic Supplementary Material (ESI) for ChemComm.This journal is © The Royal Society of Chemistry 2018

mailto:[email protected]

2

1. Theoretical Methods

The energies of the anion···anion complexes included in this study fully optimized using

the PBE0-D3/def2-TZVP level of theory by means of the program TURBOMOLE version

7.0.1 The minimum nature of the complexes has been verified by performing frequency

calculations. To evaluate the interactions in the solid state, we have used the

crystallographic coordinates at the PBE0-D3/def2-TZVP level of theory. This level of

theory includes Grimme’s correction for dispersion.2

Each relaxed scan shown in Figure 5 (see main text) was obtained by varying the C···C

distance (d) marked in the figure starting from the value of d at the local minimum,

which is d = 3.848 for 1 and d = 6.043 for 2. We have progressively increased this initial

distance by using steps of 0.1 Å until d ≈ 9Å. Then we have increased the step size to

0.25 Å and finally to 0.5 Å for the final points. Moreover, we have also computed several

points reducing the initial distance using steps of 0.1 Å to complete the scan. All

calculations have been done at the PBE0-D3/def2-TZVP level of theory and in each point

of the scan the geometry has been allowed to relax apart from the C···C distance (d).

The geometry of the second minimum observed in the relaxed scan of compound 2

(Figure 5b) is given below in Scheme S1 (left). All attempts to fully optimize (unfreezing

the C···C distance) this local minimum have been unsuccessful since the optimization

converges to the more stable local minimum. Therefore, it is not a real minimum in the

potential energy surface.

Scheme S1. Structure of the second minimum obtained in the relaxed scan of compound

2. Distances in Å

3

In order to investigate the effects of environmental factors on the strength and

directionality of anion···anion complexes we have used the PBE0-D/def2-TZVP method

along with the C-PCM implicit solvent model to mimic the crystal environment.3

The C-PCM dielectric constant used for all calculations here is 4.33, corresponding to the

dielectric constant of diethyl ether, since it has been recommended to study the effects

of the environment on the energetic and geometric attributes of the charged systems.3

The NCIplot4 isosurfaces have been used to characterize noncovalent interactions. They

correspond to both favorable and unfavorable interactions, as differentiated by the sign

of the second density Hessian eigenvalue and defined by the isosurface color. The color

scheme is a red-yellow-green-blue scale with red for ρ+cut (repulsive) and blue for ρ−

cut

(attractive).

2. Figure S1

Fig. S1. Partial view of the X-ray solid state of compound 3 (distances in Å)

3. Cartesian Coordinates

Model of compound 1

O -1.0705174 1.1126569 0.9533517

H -0.2329092 0.5603242 0.9998705

O -1.1616011 0.2816436 -1.1114235

O -4.3560286 0.1718505 0.5616412

4

H -5.1280719 0.6292298 0.9743368

O -5.1259154 -1.5709292 -3.0747565

H -5.9616134 -2.0457969 -3.1714404

O -6.4309299 -0.6268483 -1.5383885

O -6.0082752 2.0824232 0.4644900

O -5.3862156 2.7917666 -1.5893474

C -1.6316370 0.9906346 -0.2260975

C -2.8710111 1.8098177 -0.4094819

H -2.7522772 2.4226222 -1.3060051

H -2.9919431 2.4635320 0.4541366

C -4.1760523 0.9943632 -0.5570904

C -4.1547575 0.1830413 -1.8431712

H -4.1078022 0.8817547 -2.6855176

H -3.2679955 -0.4507877 -1.9051834

C -5.3601850 -0.6690598 -2.0756177

C -5.3255733 2.0714632 -0.5830249

O 1.0632325 -1.1255856 -0.9184901

H 0.2278473 -0.5701118 -0.9665863

O 1.1591715 -0.2870829 1.1431295

O 4.3440966 -0.2016683 -0.5682600

H 5.1102855 -0.6685305 -0.9817993

O 5.1303637 1.6487421 2.9751895

H 5.9665068 2.1265885 3.0515516

O 6.4460950 0.6141627 1.5079928

O 5.9923069 -2.1136214 -0.4590935

5

O 5.3881853 -2.7930947 1.6102241

C 1.6263298 -1.0002911 0.2595538

C 2.8646705 -1.8205634 0.4442410

H 2.7539281 -2.4176509 1.3521697

H 2.9753533 -2.4885262 -0.4098603

C 4.1733389 -1.0061946 0.5648343

C 4.1673417 -0.1741766 1.8382750

H 4.1457044 -0.8621119 2.6908682

H 3.2758111 0.4515994 1.9078706

C 5.3705778 0.6906174 2.0318471

C 5.3201655 -2.0862019 0.5950615

Model of compound 2

H -1.1119545 1.7535419 0.0481923

O -1.2977078 6.0595635 0.9087692

O -0.6132077 5.2830803 -1.0582077

H -1.3618219 5.8361485 -1.3142975

O -0.9571736 2.6067826 0.5010508

O 0.3086167 0.1621761 2.1830424

H 0.0785891 -0.8328062 2.0019735

O 1.5811576 -0.0032124 0.3526171

O 0.3218760 2.2380338 -1.9014087

O 2.0818271 3.4341179 -1.2072939

C -0.5716645 5.3230794 0.2796341

C 0.4710418 4.4285865 0.8714587

H 0.3468459 4.4914818 1.9534812

6

H 1.4579738 4.8010444 0.5817097

C 0.3879894 2.9697370 0.4013330

C 1.2780676 2.1437105 1.3659871

H 2.3197169 2.3752653 1.1356480

H 1.0405512 2.4350856 2.3918392

C 1.0710977 0.6526226 1.2457528

C 0.9955942 2.8679152 -1.0467755

H 1.1119545 -1.7535419 -0.0481923

O 1.2977078 -6.0595635 -0.9087692

O 0.6132077 -5.2830803 1.0582077

H 1.3618219 -5.8361485 1.3142975

O 0.9571736 -2.6067826 -0.5010508

O -0.3086167 -0.1621761 -2.1830424

H -0.0785891 0.8328062 -2.0019735

O -1.5811576 0.0032124 -0.3526171

O -0.3218760 -2.2380338 1.9014087

O -2.0818271 -3.4341179 1.2072939

C 0.5716645 -5.3230794 -0.2796341

C -0.4710418 -4.4285865 -0.8714587

H -0.3468459 -4.4914818 -1.9534812

H -1.4579738 -4.8010444 -0.5817097

C -0.3879894 -2.9697370 -0.4013330

C -1.2780676 -2.1437105 -1.3659871

H -2.3197169 -2.3752653 -1.1356480

H -1.0405512 -2.4350856 -2.3918392

7

C -1.0710977 -0.6526226 -1.2457528

C -0.9955942 -2.8679152 1.0467755

4. Experimental methods

4.1. Materials and measurements.

Fentanyl citrate used was of reagent grade and used as received from Kern

Pharma (form I). A polymorph screening has been carried out (Table S1) and as a

result, four forms have been isolated and characterized: a 1.125 hydrate

(Compound 1) has been obtained by slow crystallization in water after 19 days at

25 ºC. Anhydrous form I (Compound 2) has been obtained by slow crystallization

in MEK after 1 day at 25 ºC. Toluene solvate (Compound 3) has been obtained by

slow crystallization in a mixture toluene-methanol after 1 day at 25 ºC. Anhydrous

form II (Compound 4) has been obtained by slurring in toluene (72 h) and dried

under vacuum at 25 ºC.

4.2 Differential Scanning Calorimetry (DSC). Differential scanning calorimetry

analysis were carried out by means of a Mettler-Toledo DSC-822e calorimeter.

Experimental conditions: aluminium crucibles of 40 L volume, atmosphere of dry

nitrogen with 50 mL/min flow rate, heating rate of 10 °C/min. The calorimeter

was calibrated with indium of 99.99% purity (m.p.: 156.8 ºC; ΔH: 28.47 J/g).

4.3 Thermogravimetric Analysis (TGA). Thermogravimetric analyses were

performed on a Mettler-Toledo TGA-851e thermobalance. Experimental

conditions: alumina crucibles of 70 L volume, atmosphere of dry nitrogen with

50 mL/min flow rate, heating rate of 10 C/min.

4.4 Nuclear Magnetic Resonance (NMR). Proton nuclear magnetic resonance

(1H-NMR) spectra has been recorded on a Varian Mercury 400 (400 MHz).

Chemical shifts for proton are reported in parts per million (ppm) downfield from

tetramethylsilane and are referenced to residual proton in the NMR solvent

(DMSO-d6: δ 2.50). Experimental conditions: delay: 1; pulse: 45º; scans: 64.

8

Table S1. Screening of fentanyl citrate

Methodology Nº Experiments Nº Solids Form obtained (according to PXRD)

Evaporations at room temperature (solubility study) 19 15 Compounds 1, 2 and 5

Slurry experiments (solubility study) 11 11 Compounds 2, 3, 4 and 6

Slurry experiments 16 21 Compounds 1, 2, 3, 4 and 6

Crystallizations at slow cooling rate 7 6 Compound 1 and 3

9

4.5. X-ray crystallographic analysis.

4.5.1 Single crystal X-ray diffraction intensity data of Sildenafil form I and

acetonitrile solvate form I were collected using a D8 Venture system equipped

with a multilayer monochromator and a Mo microfocus (λ = 0.71073 Å). Frames

were integrated with the Bruker SAINT software package using a SAINT algorithm.

Data were corrected for absorption effects using the multi-scan method

(SADABS).5 The structure was solved and refined using the Bruker SHELXTL

Software Package, a computer program for automatic solution of crystal

structures and refined by full-matrix least-squares method with ShelXle Version

4.8.0, a Qt graphical user interface for SHELXL computer program.6

4.5.2 Powder X-ray diffraction patterns of polymorph screening were obtained on

a PANalytical X’Pert PRO MPD diffractometer in transmission configuration using

Cu Kα1+2 radiation (λ = 1.5406 Å) with a focalizing elliptic mirror and a PIXcel

detector working at a maximum detector’s active length of 3.347°. Configuration

of convergent beam with a focalizing mirror and a transmission geometry with

flat samples sandwiched between low absorbing films measuring from 2 to 40° in

2θ, with a step size of 0.026° and a total measuring time of 15 and 30 minutes.

The powder diffractograms were indexed and the lattice parameters were refined

by means of LeBail fits by means of Dicvol04,7 and the space groups were

determined from the systematic absences.

10

5.- Crystal data and structure refinement

5.1 Compound 1 (1.125 hydrate) (mo_023TB220_0m_a): CCDC 1877765

Table S2. Crystal data and structure refinement for mo_023TB220_0m_a.Identification code mo_023TB220_0m_aEmpirical formula C224 H306 N16 O74Formula weight 4406.83Temperature 100(2) KWavelength 0.71073 ÅCrystal system MonoclinicSpace group C 2/cUnit cell dimensions a = 34.603(2) Å = 90°.

b = 9.5694(6) Å = 120.599(2)°.c = 20.2633(12) Å = 90°.

Volume 5775.4(6) Å3

Z 1Density (calculated) 1.267 Mg/m3

Absorption coefficient 0.095 mm-1

F(000) 2354Crystal size 0.425 x 0.341 x 0.302 mm3

Theta range for data collection 2.335 to 30.607°.Index ranges -49<=h<=49, -13<=k<=13, -28<=l<=27Reflections collected 109161Independent reflections 8854 [R(int) = 0.0759]Completeness to theta = 25.242° 99.9 % Absorption correction Semi-empirical from equivalentsMax. and min. transmission 0.7461 and 0.6425Refinement method Full-matrix least-squares on F2

Data / restraints / parameters 8854 / 0 / 383Goodness-of-fit on F2 1.018Final R indices [I>2sigma(I)] R1 = 0.0516, wR2 = 0.1193R indices (all data) R1 = 0.0766, wR2 = 0.1329Extinction coefficient n/aLargest diff. peak and hole 0.441 and -0.351 e.Å-3

CCDC 1877765

Table S3. Torsion angles [°] for mo_023TB220_0m_a.

Donor --- H....Acceptor [ ARU ] D - H H...A D...A D - H...A

--------------------------------------------------------------------------------------------------------

N2 --H2 ..O7 [ ] 1.00 2.29 3.1788(16) 147

N2 --H2 ..O8 [ ] 1.00 1.87 2.7798(16) 149

O2 --H2C ..O3 [1-x,-y,1-z] 0.98(2) 1.65(2) 2.6279(17) 175.9(16)

O4 --H4O ..O7 [ ] 0.84 2.08 2.5927(19) 119

O1W --H1WA ..O1 [x,1-y,-1/2+z] 0.80(3) 2.03(3) 2.804(2) 162(2)

O1W --H1WB ..O8 [ ] 0.90(2) 1.85(2) 2.7209(16) 162(3)

O5 --H50 ..O1W [1/2-x,-1/2+y,1/2-z] 0.89(2) 1.728(18) 2.5817(18) 161.3(15)

11

5.2 Compound 2 (anhydrous form I) (mo_023VB133_0m_a): CCDC 1877766

Table S4. Crystal data and structure refinement for mo_023VB133_0m_a.Identification code mo_023VB133_0m_aEmpirical formula C28 H36 N2 O8Formula weight 528.59Temperature 100(2) KWavelength 0.71073 ÅCrystal system TriclinicSpace group P -1Unit cell dimensions a = 8.9630(5) Å = 109.411(2)°.

b = 11.2533(7) Å = 96.728(2)°.c = 14.8740(9) Å = 107.486(2)°.

Volume 1309.72(14) Å3






CCDC 18877766

Table S5. Hydrogen bonds for mo_023VB133_0m_a.

Donor --- H....Acceptor [ ARU ] D - H H...A D...A D - H...D

N(2) --H(2) ..O(8) [ -1+x,y,z] 1.00 1.66 2.6330(13) 162

O(3) --H(3) ..O(1) [ ] 0.864(17) 1.760(17) 2.6228(12) 175.8(10)

O(4) --H(4O) ..O(7) [ ] 0.855(19) 2.29(2) 2.6467(11) 105.2(16)

O(4) --H(4O) ..O(6) [ 1-x,-y,1-z] 0.855(19) 2.19(2) 3.0076(12) 161(2)

O(5) --H(5A) ..O(7) [ 1-x,-y,1-z] 0.895(15) 1.675(16) 2.5691(12) 176.3(17)

12

5.3 Compound 3 (toluene solvate) (mo_023VB214_0m_a): CCDC 1877768

Table S6. Crystal data and structure refinement for mo_023VB214_0m_a.Identification code mo_023VB214_0m_aEmpirical formula C35 H44 N2 O8Formula weight 620.72Temperature 100(2) KWavelength 0.71073 ÅCrystal system MonoclinicSpace group P 21/cUnit cell dimensions a = 17.9040(12) Å = 90°.

b = 9.6858(6) Å = 108.125(3)°.c = 19.3593(13) Å = 90°.

Volume 3190.6(4) Å3






CCDC 18877768

Table S7. Hydrogen bonds for mo_023VB214_0m_a.

Donor --- H....Acceptor [ ARU ] D - H H...A D...A D - H...A

-------------------------------------------------------------------------------------------------------

N(1) --H(1) ..O(6) [ ] 1.00 1.71 2.6975(18) 168

O(2) --H(2A) ..O(5) [ ] 0.83(2) 2.299(16) 2.6776(17) 108.3(9)

O(2) --H(2A) ..O(7) [1-x,-1/2+y,3/2-z] 0.83(2) 1.974(19) 2.7424(17) 153.7(16)

O(4) --H(4) ..O(5) [1-x,-1/2+y,3/2-z] 0.89(3) 1.92(2) 2.7173(16) 148.4(17)

O(8) --H(8) ..O(5) [1-x,1/2+y,3/2-z] 0.91(2) 1.75(2) 2.6559(16) 174.7(19)

13

6.- Characterization of the solids

Figure S2: DSC of compound 1 (1.125 hydrate), open crucible

Onset 145,63 °COnset 77,18 °C

Integral -49,60 mJ normalized -50,31 Jg^-1Onset 148,55 °C

Integral 67,60 mJ normalized 68,56 Jg^-1Onset 102,23 °C


mW

-2,5

-2,0

-1,5

-1,0

-0,5

0,0

0,5

1,0

1,5

min

°C40 60 80 100 120 140 160 180 200 220 240 260

0 2 4 6 8 10 12 14 16 18 20 22

^exo

SW 8.10eRTASUnitat de Pol imorfisme i Calorimetria: CPV

14

Figure S3: DSC of compound 1 (1.125 hydrate), sealed crucible

Integral -96,00 mJ normalized -48,88 Jg^-1Peak 117,96 °C

O nset 115,38 °C

mW

-5

-4

-3

-2

-1

0

min

°C30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

exo

SW 8.10eRTASUnitat de Polimorf isme i Calorimetria: CPV

15

Figure S4: TGA of compound 1 (1.125 hydrate)

Content 29,9315 % 1,2170 mgLeft Limit 129,51 °CRight Limit 224,78 °C


mg

1,8

2,0

2,2

2,4

2,6

2,8

3,0

3,2

3,4

3,6

3,8

4,0

min

°C40 60 80 100 120 140 160 180 200 220 240 260 280

0 2 4 6 8 10 12 14 16 18 20 22 24 26

SDTA signal

°C

-0,6

-0,4

-0,2

0,0

0,2

0,4

0,6

min

°C40 60 80 100 120 140 160 180 200 220 240 260 280

0 2 4 6 8 10 12 14 16 18 20 22 24 26

^exo


16

Figure S5: PXRD of compound 1 (1.125 hydrate)

Position [°2Theta] (Copper (Cu))

10 20 30

Counts

0

10000

40000

17

Figure S6: 1H-NMR (dmso-d6/delay: 1/pulse: 45º/scans: 64) of compound 1 (1.125 hydrate)

0.00.51.01.52.02.53.03.54.04.55.05.56.06.57.07.58.0f1 (ppm)

-500

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

6000

6500

7000

7500

2.81

1.87

3.67

13.8

6

4.43

1.00

6.55

2.75

0.85

0.87

0.88

1.36

1.38

1.80

1.82

1.86

2.48

2.54

2.58

2.62

2.68

2.79

2.87

3.27

3.29

4.58

4.60

4.63

7.17

7.19

7.22

7.24

7.25

7.27

7.43

7.44

7.46

7.48

18

Figure S7: DSC of compound 2 (anhydrous form I)

Integral -198,35 mJ normalized -90,78 Jg^-1Peak 152,45 °C

Onset 149,17 °C

mW

-12

-10

-8

-6

-4

-2

0

min

°C40 60 80 100 120 140 160 180 200 220 240 260 280

0 2 4 6 8 10 12 14 16 18 20 22 24 26

^exo


19

Figure S8: TGA of compound 2 (anhydrous form I)


mg

2,0

2,2

2,4

2,6

2,8

3,0

3,2

3,4

3,6

3,8

4,0

min

°C40 60 80 100 120 140 160 180 200 220 240 260 280

0 2 4 6 8 10 12 14 16 18 20 22 24 26

SDTA signal

°C

-0,6

-0,4

-0,2

0,0

0,2

0,4

min0 2 4 6 8 10 12 14 16 18 20 22 24 26

^exo


20

Figure S9: PXRD of compound 2 (anhydrous form I)


10 20 30

Counts

0

2500

10000

22500

21

Figure S10: 1H-NMR (DMSO-d6/delay: 1/pulse: 45º/scans: 64) of compound 2 (anhydrous form I)

0.00.51.01.52.02.53.03.54.04.55.05.56.06.57.07.5f1 (ppm)

-500

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

6000

6500

3.03

2.09

4.20

15.9

3

3.13

1.00

7.34

3.09

0.85

0.87

0.88

1.38

1.80

1.82

2.47

2.48

2.48

2.49

2.49

2.50

2.54

2.58

2.62

2.79

2.87

3.29

4.60

7.17

7.19

7.20

7.22

7.24

7.25

7.27

7.29

7.43

7.44

7.46

7.48

7.50

22

Figure S11: DSC of compound 4 (anhydrous form II)

Onset 150,20 °C


Onset 118,56 °C


Integral 39,20 mJ normalized 38,81 Jg^-1Onset 124,54 °C

mW

-8

-6

-4

-2

0

2

4

min

°C40 60 80 100 120 140 160 180 200 220 240 260 280

0 2 4 6 8 10 12 14 16 18 20 22 24

^exo


23

Figure S12: TGA of compound 4 (anhydrous form II)


mg

2,0

2,2

2,4

2,6

2,8

3,0

3,2

3,4

3,6

3,8

min

°C40 60 80 100 120 140 160 180 200 220 240 260 280

0 2 4 6 8 10 12 14 16 18 20 22 24 26

SDTA signal°C

-0,8

-0,6

-0,4

-0,2

0,0

0,2

0,4

min0 2 4 6 8 10 12 14 16 18 20 22 24 26

^exo


24

Figure S13: PXRD of compound 4 (anhydrous form II)


10 20 30

Counts

0

2500

10000

25

Figure S14: The XRPD of compound4 has been indexed with the following proposed monoclinic cell: a=18.34(5) Å, b=10.253(3) Å, c=16.13(1)

Å, β= 112.71(3)º, V=2797(2) Å 3 (Figures of Merit: M= 18, F= 56), a P21/a space group is compatible with the cell.

26

Figure S15: 1H-NMR (dmso-d6/delay: 1/pulse: 45º/scans: 64) of compound 4 (anhydrous form II)

0.51.01.52.02.53.03.54.04.55.05.56.06.57.07.58.08.5f1 (ppm)

0

500

1000

1500

2000

2500

3000

3500

4000

4500

2.85

1.77

3.83

21.0

7

4.72

1.00

6.67

2.97

0.85

0.87

0.88

1.34

1.38

1.78

1.80

1.82

1.85

2.47

2.48

2.48

2.49

2.49

2.50

2.54

2.59

2.63

2.79

2.86

3.29

4.60

7.17

7.19

7.22

7.24

7.25

7.27

7.46

7.48

27

Figure S16: Comparison of the PXRD patterns of different forms of fentanyl citrate from 2 to 40 2θ: compounds 1 and 3 patterns are simulated from crystal structure

28

7.- References

1 R. Ahlrichs, M. Bär, M. Hacer, H. Horn and C. Kömel, Chem. Phys. Lett., 1989, 162, 165–169.2 S. Grimme, J. Antony, S. Ehrlich and H. Krieg, J. Chem. Phys., 2010, 132, 154104.3 J.-D. Chai and M. Head-Gordon, J. Chem. Phys., 2008, 128, 084106; (b) J.-D. Chai and M. Head-Gordon, Phys. Chem. Chem. Phys., 2008, 10, 6615; (c) J.-D. Chai and M. Head-Gordon, Chem. Phys. Lett., 2008, 467, 176; (d) M. Cossi, N. Rega, G. Scalmani and V. Barone, J. Comput. Chem., 2003, 24, 669–6814 J. Contreras-García, E. R. Johnson, S. Keinan, R. Chaudret, J. -P. Piquemal, D. N. Beratan, W. Yang, J. Chem. Theory Comput., 2011, 7, 625-632.5 SADABS Bruker AXS; Madison, Wisconsin, USA, 2004; SAINT, Software Users Guide, Version 6.0; Bruker Analytical X–ray Systems, Madison, WI, 1999. Sheldrick, G. M. SADABS v2.03: Area–Detector Absorption Correction. University of Göttingen, Germany, 1999; Saint Version 7.60A (Bruker AXS 2008); SADABS V. 2008–1 (2008).

6 Sheldrick, G. M. Acta Cryst. 2008, A64, 112–122.

7 Boultif, A.; Louër, D. Indexing of powder diffraction patterns for low-symmetry lattices by the successive dichotomy method J. Appl. Crystallogr. 1991, 24, 987–993

polymorphs and solvates Single and double H-bonded anion ... · 1 Single and double H-bonded...

Documents

Transcript of polymorphs and solvates Single and double H-bonded anion ... · 1 Single and double H-bonded...