Supplementary Information
Study of moisture sorption behavior of urea inclusion compounds with aliphatic guests and
with linear polymers
Seema Thakral
Department of Pharmaceutics, University of Minnesota Minneapolis MN 55455 USA
Present address: GVM College of Pharmacy, Murthal Road, Sonipat India
S1: Single crystal X-Ray diffraction data collection strategy and refinement
Table S1. Crystal data and structure refinement for Urea-PEG IC crystal.
Table S2. Hydrogen bond distances [Å] and angles [°] for urea-PEG IC crystal.
S2: Thermodynamic considerations: calculation of free energies
S2A: Free energy calculations for different arrangements of urea-water binary system
S2B: Calculation of standard free energy of chemical species involved in the deliquescence
behavior of urea-hexadecane inclusion compound (UHD)
S2C: Free energy calculations for different arrangements of UHD-water binary system
Table S3: Table showing free energy calculations for different arrangements of urea-water
binary system
Table S4: Table showing free energy calculations for different arrangements of UHD-water
binary system
S1: Single crystal X-Ray diffraction data collection strategy and refinement for ureaPEG inclusion compound.
CCDC 915811 contains the supplementary crystallographic data for this Structure.
Table S1. Crystal data and structure refinement for Urea-PEG IC crystal
________________________________________________________________________________
Identification code
12225s
Empirical formula
C1.5 H6 N3 O1.5
Formula weight
90.09
Temperature
173(2) K
Wavelength
0.71073 Å
Crystal system
Trigonal
Space group
P3221
Unit cell dimensions
a = 10.493 Å
 = 90°
b = 10.493 Å
 = 90°
 = 120°
Volume
c = 9.134 Å
870.9 Å3
Z
6
Density (calculated)
Absorption coefficient
1.031 Mg/m3
0.089 mm-1
F(000)
288
Crystal color, morphology
grey, plate
Crystal size
0.45 x 0.24 x 0.11 mm3
Theta range for data collection
2.24 to 27.43°
Index ranges
-11  h  0, 0  k  13, 0  l  11
Reflections collected
10001
Independent reflections
771 [R(int) = 0.0290]
Observed reflections
720
Completeness to theta = 27.43°
100.0%
Absorption correction
Multi-scan
Max. and min. transmission
0.990 and 0.975
Refinement method
Full-matrix least-squares on F2
Data / restraints / parameters
Goodness-of-fit on F2
771 / 0 / 56
Final R indices [I>2sigma(I)]
R1 = 0.0262, wR2 = 0.0697
R indices (all data)
R1 = 0.0282, wR2 = 0.0707
Absolute structure parameter
1.1(19)
Largest diff. peak and hole
0.105 and -0.133 e.Å-3
1.120
__________________________________________________________________________________
_
Table S2: Hydrogen bond distances [Å] and angles [°] for urea-PEG IC crystal.(D= donor; A=
Acceptor)
________________________________________________________________________________
D-H...A
d(D-H) (Å)
d(H...A) (Å)
d(D...A) (Å)
(DHA) (deg)
________________________________________________________________________________
N1-H1A...O1#2
0.88
2.12
2.9935(15)
171.3
N1-H1B...O2
0.88
2.38
3.1368(14)
143.7
N2-H2A...O1#3
0.88
2.14
2.9507(18)
152.8
N2-H2B...O2
0.88
2.03
2.8691(15)
159.4
N3-H3A...O1#4
0.88
2.10
2.9728(16)
169.0
N3-H3B...N3#5
0.88
2.64
3.163(2)
118.8
________________________________________________________________________________
S2: Thermodynamic considerations
S2A: Free energy calculations for different arrangements of urea water binary system
Table S3: Free energy calculations for different arrangements of urea water binary system [M
Molality of urea; aw activity of water at corresponding M, x1 mole fraction of urea, x2 mole
fraction of water, γ1 activity coefficient urea; µH2O sol chemical potential of water in x1 urea
molar solution; µurea aq chemical potential of urea in x1 molar solution; Gf aqueous total free
energy of urea aqueous solution; Gf crystal-vapor total free energy of urea crystal- water vapor
system; Gf crystal-liquid total free energy of urea crystal-water liquid system]
Standard chemical potential of chemical species involved in the deliquescence behavior of
urea as per Table 3 of the manuscript
M
urea
x1
x2
γ1
µH20 sol
µurea aq
x2 µ H20 sol
aw
x1 µurea
x1 µurea
x2 µ H20
aq
crystal
liquid
Gf aqueous
KJ/mol
Gf
crystal-
vapor
Gf crystalliquid
0.10
1.00
0.00
1.00
0.99
-237.13
-219.52
-236.71
-0.39
-0.35
-236.70
-237.10
KJ/mol
-237.06
KJ/mol
-237.06
0.50
0.99
0.01
0.99
0.96
-237.15
-205.65
-235.03
-1.83
-1.76
-235.02
-236.87
-236.79
-236.77
1.00
0.98
0.02
0.98
0.94
-237.17
-204.00
-232.98
-3.61
-3.49
-232.94
-236.59
-236.47
-236.42
2.00
0.97
0.03
0.97
0.90
-237.22
-202.40
-228.97
-7.03
-6.85
-228.89
-236.01
-235.82
-235.74
3.00
0.95
0.05
0.95
0.86
-237.25
-201.49
-225.10
-10.32
-10.10
-224.98
-235.42
-235.20
-235.08
4.00
0.94
0.07
0.93
0.84
-237.29
-200.85
-221.36
-13.49
-13.24
-221.20
-234.85
-234.60
-234.44
5.00
0.92
0.08
0.92
0.81
-237.33
-200.36
-217.73
-16.54
-16.28
-217.55
-234.28
-234.01
-233.83
6.00
0.91
0.10
0.90
0.80
-237.37
-199.96
-214.23
-19.49
-19.22
-214.02
-233.72
-233.45
-233.23
7.00
0.90
0.11
0.89
0.78
-237.40
-199.63
-210.84
-22.34
-22.06
-210.60
-233.17
-232.90
-232.66
8.00
0.88
0.13
0.87
0.77
-237.44
-199.34
-207.55
-25.09
-24.81
-207.28
-232.64
-232.37
-232.10
9.00
0.87
0.14
0.86
0.76
-237.47
-199.08
-204.37
-27.75
-27.48
-204.07
-232.12
-231.85
-231.56
10.00
0.86
0.15
0.85
0.75
-237.51
-198.85
-201.28
-30.33
-30.07
-200.96
-231.61
-231.35
-231.03
12.00
0.84
0.18
0.82
0.74
-237.58
-198.43
-195.38
-35.25
-35.02
-195.01
-230.62
-230.40
-230.03
14.00
0.81
0.20
0.80
0.73
-237.64
-198.08
-189.82
-39.87
-39.68
-189.40
-229.68
-229.49
-229.08
16.00
0.79
0.22
0.78
0.73
-237.71
-197.77
-184.56
-44.22
-44.08
-184.11
-228.78
-228.64
-228.19
18.00
0.77
0.24
0.76
0.72
-237.78
-197.49
-179.60
-48.32
-48.24
-179.10
-227.92
-227.84
-227.35
20.00
0.75
0.26
0.74
0.72
-237.85
-197.23
-174.89
-52.20
-52.18
-174.36
-227.10
-227.08
-226.55
25.00
0.75
0.31
0.69
0.77
-237.85
-196.52
-164.04
-60.98
-61.18
-163.54
-225.02
-225.22
-224.72
30.00
0.75
0.35
0.65
0.82
-237.85
-195.92
-154.45
-68.69
-69.13
-153.98
-223.15
-223.58
-223.11
S2B: Calculation of standard free energy of chemical species involved in the
deliquescence behavior of urea-hexadecane inclusion compound (UHD)
a) Standard free energy of formation of UHD
The standard equation for calculation of UHD free energy can be applied:
∆G°f product = Σ ∆G°f reactants + ∆Gf reaction
∆G°f urea-HD IC = ∆G°f urea + ∆G°f HD + ∆Gf IC formation
∆G°f urea = -197.15 KJ/mole of urea
(From reference # [32])
∆G°f HD = -83.74 KJ/mol of HD
(From http://chemeo.com/cid/59-086-2, accessed Sept. 2012)
∆Gf reaction per mole of guest = 10.46 – 1.66 n
(where n is no of carbon atoms in the alkane chain)
(From reference # [35])
= -16.1 KJ/mol per mole of HD
∆G°f urea-HD IC (per mole of urea) = (∆G°f urea-HD IC (per mole of guest))/12
(The molal composition of urea-hexadecane inclusion compound is known to be 12:1).
={(- 197.15X 12)-83.74-16.1}/12
=-205.47KJ/ mole of urea
b) Standard free energy of formation of UHDaq (formation of aqueous solution of
UHD)
In the event of lack of any data on free energy of formation of aqueous solution of UHD, the
same was roughly estimated as summation of free energy accompanying decomposition of
UHD, free energy of formation of urea(aq) and of hydration of HD.
UHD(solid)
UHD (in solution)
complex decomposition
Urea (aq) + HD (aq)
Thus the required values were extracted from reported literature:
∆Gf IC decomposition = - ∆Gf IC formation = 16.1 KJ/mol of HD
(From reference # [35])
∆Gf urea aqueous = -203.84 KJ/ mole of urea
= -203.84X12 = -2446.08 KJ/ mole of HD
(From reference # [32])
∆Gf HD aqueous =
+25.31 KJ/ mole of HD (From BioChem. Biophys Chem, 2001,93, 6782)
Hence ∆Gf UHDaq = (-2446.08 + 25.31 + 16.1)
= -2404.67/ mole of HD
= -200.4 KJ/mol of urea
S2C: Free energy calculations for different arrangements of UHD-water binary system
Table S4: [M Molality of urea; aw activity of water at corresponding M, x1 mole fraction of
urea, x2 mole fraction of water, γ1 activity coefficient urea; µH2O sol chemical potential of water
in x1 urea molar solution; µUHD aq chemical potential of urea in x1 molar solution; Gf aqueous
total free energy for formation of UHD aqueous solution, Gf crystal-vapor total free energy of
formation of UHD crystal- water vapor system; Gf crystal-liquid total free energy of formation of
UHD crystal-water liquid system]
M
Urea
x1
x2
aw
γ1
µH20 sol at
x2
µUHD aq
x1
x2 *µ
H20 sol
x1 *
µUHD aq
x1 *
µUHD
x2
*µ H20
crystal
liquid
Gf
Gf
aqueous
crystal-
KJ/mol
vapor
Gf crystalliquid
KJ/mol
0.7
0.01
0.99
0.987
0.15
-237.16
-215.76
-234.15
-2.74
-2.61
-234.12
-236.89
KJ/mol
-236.76
1.8
0.03
0.97
0.971
0.45
-237.20
-210.89
-229.81
-6.58
-6.40
-229.74
-236.38
-236.21
-236.14
2.5
0.04
0.96
0.96
0.55
-237.23
-209.57
-227.01
-9.03
-8.86
-226.91
-236.04
-235.86
-235.76
3.2
0.05
0.95
0.949
0.62
-237.26
-208.68
-224.27
-11.42
-11.25
-224.15
-235.69
-235.52
-235.39
3.9
0.07
0.93
0.939
0.67
-237.29
-208.04
-221.6
-13.75
-13.58
-221.45
-235.35
-235.18
-235.04
4.6
0.08
0.92
0.929
0.70
-237.31
-207.53
-218.99
-16.02
-15.86
-218.82
-235.01
-234.85
-234.69
5
0.08
0.92
0.924
0.71
-237.33
-207.31
-217.71
-17.13
-16.98
-217.53
-234.85
-234.69
-234.51
6.1
0.099
0.901
0.909
0.75
-237.37
-206.75
-213.96
-20.39
-20.26
-213.75
-234.35
-234.22
-234.01
6.4
0.104
0.896
0.905
0.76
-237.38
-206.61
-212.74
-21.45
-21.33
-212.51
-234.18
-234.06
-233.84
7.1
0.114
0.886
0.895
0.77
-237.41
-206.32
-210.33
-23.53
-23.43
-210.09
-233.86
-233.76
-233.52
7.5
0.119
0.881
0.887
0.79
-237.44
-206.15
-209.16
-24.54
-24.46
-208.9
-233.70
-233.62
-233.36
8.2
0.129
0.871
0.879
0.80
-237.45
-205.93
-206.84
-26.55
-26.49
-206.56
-233.39
-233.33
-233.05
8.9
0.138
0.862
0.869
0.81
-237.48
-205.71
-204.57
-28.51
-28.47
-204.27
-233.08
-233.04
-232.74
9.6
0.148
0.852
0.86
0.82
-237.50
-205.52
-202.35
-30.42
-30.41
-202.02
-232.77
-232.76
-232.44
10
0.152
0.847
0.858
0.818
-237.51
-205.45
-201.25
-31.37
-31.37
-200.93
-232.62
-232.62
-232.30
10.7
0.162
0.838
0.855
0.808
-237.52
-205.34
-199.08
-33.27
-33.25
-198.76
-232.31
-232.33
-232.01
11.8
0.175
0.825
0.849
0.799
-237.54
-205.17
-195.93
-35.94
-35.99
-195.59
-231.87
-231.92
-231.58
12.1
0.179
0.821
0.849
0.792
-237.54
-205.13
-194.89
-36.82
-36.88
-194.56
-231.72
-231.78
-231.45
12.5
0.184
0.816
0.849
0.785
-237.54
-205.10
-193.87
-37.70
-37.77
-193.54
-231.57
-231.64
-231.31
13.2
0.192
0.808
0.849
0.771
-237.54
-205.03
-191.86
-39.43
-39.51
-191.53
-231.28
-231.37
-231.04
15
0.213
0.787
0.849
0.743
-237.54
-204.87
-186.99
-43.589
-43.71
-186.68
-230.58
-230.71
-230.39
17
0.234
0.766
0.849
0.718
-237.54
-204.71
-181.84
-48.00
-48.18
-181.53
-229.84
-230.02
-229.71
-236.73