organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

rac-4-(2-Meth­­oxy­phen­yl)-2,6-di­methyl­cyclo­hex-3-ene­carb­­oxy­lic acid

aDepartment of Natural, Information, and Mathematical Sciences, Indiana University Kokomo, Kokomo, IN 46904–9003, USA, and bIndiana University Molecular Structure Center, Indiana University, Bloomington, IN 47405–7102, USA
*Correspondence e-mail: soxie@iuk.edu

(Received 17 May 2010; accepted 25 May 2010; online 29 May 2010)

The title compound, C16H20O3, was synthesized to study the hydrogen-bonding inter­actions of the two enanti­omers in the solid state. Inter­molecular O—H⋯O hydrogen bonds produce centrosymmetric R22(8) rings which dimerize the two chiral enanti­omers together through their carboxyl groups.

Related literature

In similar compounds previously reported (Xie et al., 2002[Xie, S., Hou, Y., Meyers, C. Y. & Robinson, P. D. (2002). Acta Cryst. E58, o1460-o1462.], 2007a[Xie, S., Kenny, C. & Robinson, P. D. (2007a). Acta Cryst. E63, o3897.], 2008a[Xie, S., O'Hearn, C. R. & Robinson, P. D. (2008a). Acta Cryst. E64, o554.],b[Xie, S., Stein, H. J. & Pink, M. (2008b). Acta Cryst. E64, o1869.]), the racemates also consist of carb­oxy­lic acid RS dimers. For the structure of the precursor, see: Xie et al. (2007b[Xie, S., Kenny, C. & Robinson, P. D. (2007b). Acta Cryst. E63, o1660-o1662.]). The chirality of the title compound is solely generated by the presence of the double bond in the cyclo­hexene ring, see: Xie et al. (2004[Xie, S., Meyers, C. Y. & Robinson, P. D. (2004). Acta Cryst. E60, o1362-o1364.]). For hydrogen-bond motifs, see: Bernstein et al. (1995[Bernstein, J., Davis, R., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555-1573.]).

[Scheme 1]

Experimental

Crystal data
  • C16H20O3

  • Mr = 260.32

  • Monoclinic, P 21 /c

  • a = 14.2283 (9) Å

  • b = 7.1202 (5) Å

  • c = 14.9517 (10) Å

  • β = 106.069 (2)°

  • V = 1455.55 (17) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.08 mm−1

  • T = 150 K

  • 0.25 × 0.23 × 0.07 mm

Data collection
  • Bruker APEXII Kappa Duo diffractometer

  • Absorption correction: multi-scan (SADABS; Sheldrick, 1996[Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany.]) Tmin = 0.980, Tmax = 0.994

  • 11165 measured reflections

  • 2964 independent reflections

  • 2296 reflections with I > 2σ(I)

  • Rint = 0.022

Refinement
  • R[F2 > 2σ(F2)] = 0.048

  • wR(F2) = 0.138

  • S = 1.04

  • 2964 reflections

  • 179 parameters

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.56 e Å−3

  • Δρmin = −0.34 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O2—H2⋯O1i 0.88 (3) 1.79 (3) 2.6640 (18) 177 (3)
Symmetry code: (i) -x+2, -y+1, -z.

Data collection: APEX2 (Bruker, 2007[Bruker (2007). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2007[Bruker (2007). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SIR2004 (Burla et al., 2005[Burla, M. C., Caliandro, R., Camalli, M., Carrozzini, B., Cascarano, G. L., De Caro, L., Giacovazzo, C., Polidori, G. & Spagna, R. (2005). J. Appl. Cryst. 38, 381-388.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: SHELXL97.

Supporting information


Comment top

The title carboxylic acid was prepared to study the interaction of the two enantiomers in the solid state. We have previously reported the structure of its precursor, which is achiral and forms hydrogen-bonded dimers (Xie et al., 2007b). The chirality of the title compound is solely generated by the presence of the double bond in the cyclohexene ring (Xie et al., 2004). The resultant racemate is made up of carboxylic acid RS dimers (Xie et al., 2002, 2007a, 2008a,b). The structure and atom numbering are shown in Fig. 1, which illustrates the half-chair conformation of the cyclohexene ring. The torsion angles involving atoms C4, C5, C6, C1, and C2 are near 0°. The carboxyl group is almost perpendicular to the cyclohexene ring with an angle of 82.2° between the O1—C14—O2—C3 plane and the C1—C6 ring. The double bond between C5—C6 is not fully conjugated with the aromatic ring as shown by the C1—C6—C5 plane to benzene ring angle of 52.6°. Unlike other previously reported para substituted analogs and like other previously reported meta substituted analogs (Xie et al., 2008b), the molecule also has a chiral axis due to the ortho methoxy substituent on the aromatic ring.

Fig. 2 shows the hydrogen bonding scheme. Atom O2 acts as a donor in an intermolecular hydrogen bond to atom O1, producing an R22(8) ring (Bernstein et al., 1995), thus creating a hydrogen- bonded dimer. There is no evidence to suggest that weak directional interactions interconnect the dimers. Hydrogen bond geometry is given in Table 1.

Related literature top

In similar compounds previously reported (Xie et al., 2002, 2007a, 2008a,b), the racemates also consist of carboxylic acid RS dimers. For the structure of the precursor, see: Xie et al. (2007b). The chirality of the title compound is solely generated by the presence of the double bond in the cyclohexene ring, see: Xie et al. (2004). For hydrogen-bond motifs, see: Bernstein et al. (1995).

Experimental top

The title carboxylic acid was synthesized following asimilar method reported by Xie et al., 2002. Purified compound was recrystallized from hexane- dichloromethane as colorless plates (m.p. 417-418 K).

Refinement top

All non-hydrogen atoms were refined with anisotropic displacement parameters. The hydrogen atoms not involved in hydrogen bonding were placed in ideal positions and refined as riding atoms with relative isotropic displacement parameters. H1 was freely refined.

Structure description top

The title carboxylic acid was prepared to study the interaction of the two enantiomers in the solid state. We have previously reported the structure of its precursor, which is achiral and forms hydrogen-bonded dimers (Xie et al., 2007b). The chirality of the title compound is solely generated by the presence of the double bond in the cyclohexene ring (Xie et al., 2004). The resultant racemate is made up of carboxylic acid RS dimers (Xie et al., 2002, 2007a, 2008a,b). The structure and atom numbering are shown in Fig. 1, which illustrates the half-chair conformation of the cyclohexene ring. The torsion angles involving atoms C4, C5, C6, C1, and C2 are near 0°. The carboxyl group is almost perpendicular to the cyclohexene ring with an angle of 82.2° between the O1—C14—O2—C3 plane and the C1—C6 ring. The double bond between C5—C6 is not fully conjugated with the aromatic ring as shown by the C1—C6—C5 plane to benzene ring angle of 52.6°. Unlike other previously reported para substituted analogs and like other previously reported meta substituted analogs (Xie et al., 2008b), the molecule also has a chiral axis due to the ortho methoxy substituent on the aromatic ring.

Fig. 2 shows the hydrogen bonding scheme. Atom O2 acts as a donor in an intermolecular hydrogen bond to atom O1, producing an R22(8) ring (Bernstein et al., 1995), thus creating a hydrogen- bonded dimer. There is no evidence to suggest that weak directional interactions interconnect the dimers. Hydrogen bond geometry is given in Table 1.

In similar compounds previously reported (Xie et al., 2002, 2007a, 2008a,b), the racemates also consist of carboxylic acid RS dimers. For the structure of the precursor, see: Xie et al. (2007b). The chirality of the title compound is solely generated by the presence of the double bond in the cyclohexene ring, see: Xie et al. (2004). For hydrogen-bond motifs, see: Bernstein et al. (1995).

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SIR2004 (Burla et al., 2005); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXL97 (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure showing thermal ellipsoids at the 50% probability level and the atom numbering scheme.
[Figure 2] Fig. 2. Hydrogen bonded dimer. Dashed lines represent hydrogen bonds (symmetry code: #1 -x+2,-y+3,-z).
4-(2-Methoxyphenyl)-2,6-dimethylcyclohex-3-enecarboxylic acid top
Crystal data top
C16H20O3F(000) = 560
Mr = 260.32Dx = 1.188 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 4026 reflections
a = 14.2283 (9) Åθ = 2.8–26.3°
b = 7.1202 (5) ŵ = 0.08 mm1
c = 14.9517 (10) ÅT = 150 K
β = 106.069 (2)°Plate, colorless
V = 1455.55 (17) Å30.25 × 0.23 × 0.07 mm
Z = 4
Data collection top
Bruker APEXII Kappa Duo
diffractometer
2964 independent reflections
Radiation source: fine-focus sealed tube2296 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.022
Detector resolution: 83.33 pixels mm-1θmax = 26.4°, θmin = 1.5°
ω and φ scansh = 1617
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
k = 78
Tmin = 0.980, Tmax = 0.994l = 1318
11165 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.048Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.138H atoms treated by a mixture of independent and constrained refinement
S = 1.04 w = 1/[σ2(Fo2) + (0.0653P)2 + 0.6215P]
where P = (Fo2 + 2Fc2)/3
2964 reflections(Δ/σ)max = 0.001
179 parametersΔρmax = 0.56 e Å3
0 restraintsΔρmin = 0.34 e Å3
Crystal data top
C16H20O3V = 1455.55 (17) Å3
Mr = 260.32Z = 4
Monoclinic, P21/cMo Kα radiation
a = 14.2283 (9) ŵ = 0.08 mm1
b = 7.1202 (5) ÅT = 150 K
c = 14.9517 (10) Å0.25 × 0.23 × 0.07 mm
β = 106.069 (2)°
Data collection top
Bruker APEXII Kappa Duo
diffractometer
2964 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
2296 reflections with I > 2σ(I)
Tmin = 0.980, Tmax = 0.994Rint = 0.022
11165 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0480 restraints
wR(F2) = 0.138H atoms treated by a mixture of independent and constrained refinement
S = 1.04Δρmax = 0.56 e Å3
2964 reflectionsΔρmin = 0.34 e Å3
179 parameters
Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.88885 (9)0.4779 (2)0.00968 (10)0.0602 (5)
O21.02302 (9)0.3518 (2)0.10376 (10)0.0531 (4)
H2O1.051 (2)0.411 (4)0.0670 (18)0.082 (8)*
O30.55725 (8)0.14999 (17)0.09567 (7)0.0342 (3)
C10.76051 (16)0.0149 (3)0.11315 (14)0.0478 (5)
H1A0.70600.08030.06830.057*
H1B0.80790.11220.14460.057*
C20.81042 (14)0.1106 (3)0.05858 (12)0.0418 (5)
H20.75850.17710.01000.050*
C30.87036 (12)0.2591 (3)0.12493 (12)0.0366 (4)
H30.91750.19270.17750.044*
C40.80346 (14)0.3809 (3)0.16515 (13)0.0409 (4)
H40.76100.45590.11290.049*
C50.73751 (16)0.2583 (3)0.20376 (14)0.0479 (5)
H50.70530.31370.24500.057*
C60.72161 (11)0.0741 (2)0.18303 (11)0.0300 (4)
C70.66838 (11)0.0451 (2)0.23497 (10)0.0279 (4)
C80.69907 (12)0.0459 (2)0.33172 (11)0.0322 (4)
H80.75150.03370.36290.039*
C90.65520 (14)0.1596 (2)0.38384 (11)0.0377 (4)
H90.67720.15700.44990.045*
C100.57966 (14)0.2762 (3)0.33929 (12)0.0392 (4)
H100.55010.35570.37480.047*
C110.54636 (13)0.2784 (2)0.24267 (12)0.0343 (4)
H110.49420.35920.21220.041*
C120.58967 (11)0.1624 (2)0.19099 (11)0.0279 (4)
C130.87078 (18)0.0056 (4)0.00957 (17)0.0680 (7)
H13A0.89840.07660.02920.102*
H13B0.82900.10040.02970.102*
H13C0.92390.06800.05600.102*
C140.92794 (13)0.3744 (3)0.07423 (12)0.0409 (5)
C150.86046 (19)0.5186 (3)0.23835 (16)0.0615 (6)
H15A0.81460.59430.26150.092*
H15B0.89970.60130.21050.092*
H15C0.90370.44880.29010.092*
C160.47037 (14)0.2506 (3)0.05064 (12)0.0441 (5)
H16A0.45160.22230.01610.066*
H16B0.41750.21290.07720.066*
H16C0.48220.38570.05990.066*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0321 (7)0.0899 (12)0.0542 (8)0.0105 (7)0.0048 (6)0.0408 (8)
O20.0299 (7)0.0756 (11)0.0510 (8)0.0106 (7)0.0066 (6)0.0317 (7)
O30.0347 (6)0.0422 (7)0.0275 (6)0.0110 (5)0.0115 (5)0.0011 (5)
C10.0570 (12)0.0433 (11)0.0542 (11)0.0197 (9)0.0341 (10)0.0117 (9)
C20.0365 (9)0.0554 (12)0.0387 (9)0.0140 (9)0.0190 (8)0.0047 (8)
C30.0303 (9)0.0444 (10)0.0336 (8)0.0108 (8)0.0066 (7)0.0099 (7)
C40.0461 (11)0.0374 (10)0.0397 (9)0.0125 (8)0.0124 (8)0.0025 (8)
C50.0604 (13)0.0390 (11)0.0554 (11)0.0104 (9)0.0346 (10)0.0058 (9)
C60.0270 (8)0.0360 (9)0.0285 (8)0.0060 (7)0.0100 (6)0.0011 (7)
C70.0277 (8)0.0292 (8)0.0294 (8)0.0019 (7)0.0121 (6)0.0008 (6)
C80.0318 (9)0.0335 (9)0.0315 (8)0.0020 (7)0.0091 (7)0.0001 (7)
C90.0475 (10)0.0398 (10)0.0274 (8)0.0071 (8)0.0129 (7)0.0056 (7)
C100.0515 (11)0.0355 (9)0.0374 (9)0.0013 (8)0.0236 (8)0.0088 (8)
C110.0382 (9)0.0314 (9)0.0374 (9)0.0046 (7)0.0173 (7)0.0010 (7)
C120.0301 (8)0.0279 (8)0.0291 (8)0.0011 (7)0.0138 (6)0.0007 (6)
C130.0605 (14)0.0884 (18)0.0704 (15)0.0219 (13)0.0437 (12)0.0283 (13)
C140.0299 (9)0.0529 (11)0.0365 (9)0.0122 (8)0.0036 (7)0.0126 (8)
C150.0778 (16)0.0467 (12)0.0576 (13)0.0251 (12)0.0148 (12)0.0074 (10)
C160.0473 (11)0.0508 (11)0.0334 (9)0.0185 (9)0.0098 (8)0.0066 (8)
Geometric parameters (Å, º) top
O1—C141.219 (2)C6—C71.491 (2)
O2—C141.312 (2)C7—C81.391 (2)
O2—H2O0.88 (3)C7—C121.406 (2)
O3—C121.3740 (19)C8—C91.386 (2)
O3—C161.426 (2)C8—H80.9500
C1—C61.456 (2)C9—C101.376 (3)
C1—C21.513 (2)C9—H90.9500
C1—H1A0.9900C10—C111.390 (2)
C1—H1B0.9900C10—H100.9500
C2—C131.519 (3)C11—C121.387 (2)
C2—C31.537 (2)C11—H110.9500
C2—H21.0000C13—H13A0.9800
C3—C141.504 (2)C13—H13B0.9800
C3—C41.528 (3)C13—H13C0.9800
C3—H31.0000C15—H15A0.9800
C4—C51.508 (2)C15—H15B0.9800
C4—C151.525 (3)C15—H15C0.9800
C4—H41.0000C16—H16A0.9800
C5—C61.352 (3)C16—H16B0.9800
C5—H50.9500C16—H16C0.9800
C14—O2—H2O110.0 (18)C9—C8—H8119.1
C12—O3—C16117.10 (12)C7—C8—H8119.1
C6—C1—C2117.26 (16)C10—C9—C8119.56 (15)
C6—C1—H1A108.0C10—C9—H9120.2
C2—C1—H1A108.0C8—C9—H9120.2
C6—C1—H1B108.0C9—C10—C11120.40 (16)
C2—C1—H1B108.0C9—C10—H10119.8
H1A—C1—H1B107.2C11—C10—H10119.8
C1—C2—C13110.54 (18)C12—C11—C10119.74 (16)
C1—C2—C3108.53 (14)C12—C11—H11120.1
C13—C2—C3113.54 (16)C10—C11—H11120.1
C1—C2—H2108.0O3—C12—C11122.89 (15)
C13—C2—H2108.0O3—C12—C7116.24 (13)
C3—C2—H2108.0C11—C12—C7120.84 (15)
C14—C3—C4111.98 (15)C2—C13—H13A109.5
C14—C3—C2109.42 (14)C2—C13—H13B109.5
C4—C3—C2110.45 (14)H13A—C13—H13B109.5
C14—C3—H3108.3C2—C13—H13C109.5
C4—C3—H3108.3H13A—C13—H13C109.5
C2—C3—H3108.3H13B—C13—H13C109.5
C5—C4—C15111.17 (16)O1—C14—O2122.86 (16)
C5—C4—C3110.10 (15)O1—C14—C3122.40 (16)
C15—C4—C3112.43 (17)O2—C14—C3114.73 (15)
C5—C4—H4107.6C4—C15—H15A109.5
C15—C4—H4107.6C4—C15—H15B109.5
C3—C4—H4107.6H15A—C15—H15B109.5
C6—C5—C4123.77 (17)C4—C15—H15C109.5
C6—C5—H5118.1H15A—C15—H15C109.5
C4—C5—H5118.1H15B—C15—H15C109.5
C5—C6—C1120.94 (16)O3—C16—H16A109.5
C5—C6—C7120.64 (15)O3—C16—H16B109.5
C1—C6—C7118.33 (15)H16A—C16—H16B109.5
C8—C7—C12117.67 (14)O3—C16—H16C109.5
C8—C7—C6119.05 (14)H16A—C16—H16C109.5
C12—C7—C6123.25 (14)H16B—C16—H16C109.5
C9—C8—C7121.77 (16)
C6—C1—C2—C13164.10 (19)C1—C6—C7—C1253.0 (2)
C6—C1—C2—C339.0 (2)C12—C7—C8—C90.9 (2)
C1—C2—C3—C14174.85 (16)C6—C7—C8—C9177.28 (15)
C13—C2—C3—C1451.5 (2)C7—C8—C9—C100.4 (3)
C1—C2—C3—C461.4 (2)C8—C9—C10—C110.9 (3)
C13—C2—C3—C4175.22 (18)C9—C10—C11—C120.0 (3)
C14—C3—C4—C5172.34 (15)C16—O3—C12—C115.2 (2)
C2—C3—C4—C550.1 (2)C16—O3—C12—C7172.68 (15)
C14—C3—C4—C1563.1 (2)C10—C11—C12—O3176.46 (16)
C2—C3—C4—C15174.67 (15)C10—C11—C12—C71.4 (2)
C15—C4—C5—C6141.8 (2)C8—C7—C12—O3176.16 (14)
C3—C4—C5—C616.6 (3)C6—C7—C12—O35.7 (2)
C4—C5—C6—C16.3 (3)C8—C7—C12—C111.8 (2)
C4—C5—C6—C7170.29 (17)C6—C7—C12—C11176.29 (15)
C2—C1—C6—C55.8 (3)C4—C3—C14—O156.8 (3)
C2—C1—C6—C7177.46 (16)C2—C3—C14—O166.0 (3)
C5—C6—C7—C851.6 (2)C4—C3—C14—O2124.50 (18)
C1—C6—C7—C8125.06 (18)C2—C3—C14—O2112.68 (19)
C5—C6—C7—C12130.28 (19)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2—H2O···O1i0.88 (3)1.79 (3)2.6640 (18)177 (3)
Symmetry code: (i) x+2, y+1, z.

Experimental details

Crystal data
Chemical formulaC16H20O3
Mr260.32
Crystal system, space groupMonoclinic, P21/c
Temperature (K)150
a, b, c (Å)14.2283 (9), 7.1202 (5), 14.9517 (10)
β (°) 106.069 (2)
V3)1455.55 (17)
Z4
Radiation typeMo Kα
µ (mm1)0.08
Crystal size (mm)0.25 × 0.23 × 0.07
Data collection
DiffractometerBruker APEXII Kappa Duo
Absorption correctionMulti-scan
(SADABS; Sheldrick, 1996)
Tmin, Tmax0.980, 0.994
No. of measured, independent and
observed [I > 2σ(I)] reflections
11165, 2964, 2296
Rint0.022
(sin θ/λ)max1)0.625
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.048, 0.138, 1.04
No. of reflections2964
No. of parameters179
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.56, 0.34

Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), SIR2004 (Burla et al., 2005), SHELXL97 (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2—H2O···O1i0.88 (3)1.79 (3)2.6640 (18)177 (3)
Symmetry code: (i) x+2, y+1, z.
 

Acknowledgements

SX, BF, and SD are grateful for the Grant-in-aid for Faculty Research from Indiana University Kokomo, as well as the Senior Research Grant from Indiana Academy of Science.

References

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