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This work presents the crystal structure determination of two elusive polymorphs of furazidin, an antibacterial agent, employing a combination of crystal structure prediction (CSP) calculations and an NMR crystallography approach. Two previously uncharacterized neat crystal forms, one of which has two symmetry-independent molecules (form I), whereas the other one is a Z′ = 1 polymorph (form II), crystallize in P21/c and P1 space groups, respectively, and both are built by different conformers, displaying different intermolecular interactions. It is demonstrated that the usage of either CSP or NMR crystallography alone is insufficient to successfully elucidate the above-mentioned crystal structures, especially in the case of the Z′ = 2 polymorph. In addition, cases of serendipitous agreement in terms of 1H or 13C NMR data obtained for the CSP-generated crystal structures different from the ones observed in the laboratory (false-positive matches) are analyzed and described. While for the majority of analyzed crystal structures the obtained agreement with the NMR experiment is indicative of some structural features in common with the experimental structure, the mentioned serendipity observed in exceptional cases points to the necessity of caution when using an NMR crystallography approach in crystal structure determination.
Supporting information
CCDC references: 1993854; 1993855
For both structures, program(s) used to refine structure: GSAS-II (Toby & Von Dreele, J. Appl. Cryst. 46, 544-549, 2013).
Crystal data top
C10H8N4O5 | β = 106.848 (14)° |
Mr = 264.2 | V = 1087.80 (18) Å3 |
Monoclinic, P21/c | Z = 4 |
Hall symbol: -P 2ybc | Dx = 1.613 Mg m−3 |
a = 11.670 (7) Å | Cu Kα radiation |
b = 11.4666 (12) Å | T = 300 K |
c = 8.494 (4) Å | |
Data collection top
Bruker D8 with LYNXEYE detector diffractometer | |
Refinement top
Least-squares matrix: full | R(F2) = 0.04496 |
Rp = 0.071 | 1921 data points |
Rwp = 0.096 | 32 parameters |
Rexp = 0.316 | Background function: Background function: "chebyschev" function with 24 terms:
6.39(6), -11.28(29), -1.7(8), 1.0(22), 209.4(24), 78(4),
-2446.0(10), -1372.6(11), 20455.6(21), 11208(3), -117679.9(15),
-34269(4), 414751.5(7), 26568.1(15), -893273.9(17), 87213.0(23),
1.1848209(23)e6, -251999(5), -945917.0(18), 281839(4), 417242.8(5),
-151823.0(10), -78161(3), 32564(7), |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
H1 | 0.82787 | −0.06253 | 1.00513 | 0.010* | |
H5 | 0.84740 | 0.19903 | 1.07817 | 0.010* | |
H9 | 0.68180 | 0.04856 | 0.80219 | 0.010* | |
H13 | 0.39344 | 0.37273 | 0.39885 | 0.010* | |
H17 | 0.59001 | 0.09301 | 0.52272 | 0.010* | |
H21 | 0.49048 | 0.07430 | 0.64569 | 0.010* | |
H25 | 0.99900 | −0.18311 | 1.23761 | 0.010* | |
H29 | 1.18276 | −0.11085 | 1.50229 | 0.010* | |
C1 | 1.10762 | 0.05823 | 1.41747 | 0.010* | |
C5 | 0.96242 | 0.00211 | 1.20938 | 0.010* | |
C9 | 1.02283 | −0.09617 | 1.28110 | 0.010* | |
C13 | 0.86302 | 0.01664 | 1.06979 | 0.010* | |
C17 | 0.81292 | 0.11971 | 1.01347 | 0.010* | |
C21 | 0.71606 | 0.12834 | 0.86814 | 0.010* | |
C25 | 0.53259 | 0.33898 | 0.61528 | 0.010* | |
C29 | 0.43200 | 0.19445 | 0.44159 | 0.010* | |
C33 | 0.52767 | 0.13693 | 0.57693 | 0.010* | |
C37 | 1.11655 | −0.05989 | 1.41512 | 0.010* | |
N1 | 0.67265 | 0.22973 | 0.81809 | 0.010* | |
N5 | 0.58263 | 0.23383 | 0.67964 | 0.010* | |
N9 | 0.44356 | 0.31104 | 0.47203 | 0.010* | |
N13 | 1.17586 | 0.13997 | 1.52647 | 0.010* | |
O1 | 1.01514 | 0.09787 | 1.29468 | 0.010* | |
O5 | 1.26275 | 0.10219 | 1.63454 | 0.010* | |
O9 | 1.14515 | 0.24256 | 1.50909 | 0.010* | |
O13 | 0.56028 | 0.43441 | 0.67232 | 0.010* | |
O17 | 0.36065 | 0.14639 | 0.32818 | 0.010* | |
Geometric parameters (Å, º) top
H1—C13 | 1.0786 | C25—O13 | 1.2024 |
H5—C17 | 1.0784 | C29—C33 | 1.5030 |
H9—C21 | 1.0866 | C29—N9 | 1.3609 |
H13—N9 | 1.0091 | C29—O17 | 1.2083 |
H17—C33 | 1.0904 | C33—H17 | 1.0904 |
H21—C33 | 1.0919 | C33—H21 | 1.0919 |
H25—C9 | 1.0715 | C33—C29 | 1.5030 |
H29—C37 | 1.0748 | C33—N5 | 1.4432 |
C1—C37 | 1.3590 | C37—H29 | 1.0748 |
C1—N13 | 1.3937 | C37—C1 | 1.3590 |
C1—O1 | 1.3442 | C37—C9 | 1.394 |
C5—C9 | 1.3745 | N1—C21 | 1.2900 |
C5—C13 | 1.4078 | N1—N5 | 1.3314 |
C5—O1 | 1.3605 | N5—C25 | 1.3814 |
C9—H25 | 1.0715 | N5—C33 | 1.4432 |
C9—C5 | 1.3745 | N5—N1 | 1.3314 |
C9—C37 | 1.394 | N9—H13 | 1.0091 |
C13—H1 | 1.0786 | N9—C25 | 1.3891 |
C13—C5 | 1.4078 | N9—C29 | 1.3609 |
C13—C17 | 1.3435 | N13—C1 | 1.3937 |
C17—H5 | 1.0784 | N13—O5 | 1.2325 |
C17—C13 | 1.3435 | N13—O9 | 1.2261 |
C17—C21 | 1.4150 | O1—C1 | 1.3442 |
C21—H9 | 1.0866 | O1—C5 | 1.3605 |
C21—C17 | 1.4150 | O5—N13 | 1.2325 |
C21—N1 | 1.2900 | O9—N13 | 1.2261 |
C25—N5 | 1.3814 | O13—C25 | 1.2024 |
C25—N9 | 1.3891 | O17—C29 | 1.2083 |
| | | |
C37—C1—N13 | 130.432 | C33—C29—O17 | 126.661 |
C37—C1—O1 | 111.923 | N9—C29—O17 | 127.372 |
N13—C1—O1 | 117.625 | H17—C33—H21 | 109.84 |
C9—C5—C13 | 131.449 | H17—C33—C29 | 108.566 |
C9—C5—O1 | 109.328 | H21—C33—C29 | 112.046 |
C13—C5—O1 | 119.214 | H17—C33—N5 | 112.139 |
H25—C9—C5 | 124.159 | H21—C33—N5 | 111.035 |
H25—C9—C37 | 128.531 | C29—C33—N5 | 103.056 |
C5—C9—C37 | 107.31 | H29—C37—C1 | 125.073 |
H1—C13—C5 | 115.348 | H29—C37—C9 | 129.608 |
H1—C13—C17 | 119.802 | C1—C37—C9 | 105.312 |
C5—C13—C17 | 124.841 | C21—N1—N5 | 117.189 |
H5—C17—C13 | 120.056 | C25—N5—C33 | 111.713 |
H5—C17—C21 | 118.114 | C25—N5—N1 | 121.01 |
C13—C17—C21 | 121.822 | C33—N5—N1 | 127.253 |
H9—C21—C17 | 118.189 | H13—N9—C25 | 122.056 |
H9—C21—N1 | 122.557 | H13—N9—C29 | 124.317 |
C17—C21—N1 | 119.251 | C25—N9—C29 | 113.627 |
N5—C25—N9 | 105.567 | C1—N13—O5 | 116.533 |
N5—C25—O13 | 126.973 | C1—N13—O9 | 118.324 |
N9—C25—O13 | 127.458 | O5—N13—O9 | 125.141 |
C33—C29—N9 | 105.961 | C1—O1—C5 | 106.127 |
Crystal data top
C20H16N8O10 | β = 92.16 (3)° |
Mr = 528.39 | γ = 97.31 (11)° |
Triclinic, P1 | V = 1138.5 (4) Å3 |
Hall symbol: -P 1 | Z = 2 |
a = 22.18 (2) Å | Dx = 1.541 Mg m−3 |
b = 12.546 (7) Å | Cu Kα radiation |
c = 5.3092 (16) Å | T = 300 K |
α = 51.074 (3)° | |
Data collection top
Bruker D8 with LYNXEYE detector diffractometer | |
Refinement top
Least-squares matrix: full | R(F2) = 0.00000 |
Rp = 0.073 | 1921 data points |
Rwp = 0.132 | 10 parameters |
Rexp = 0.013 | Background function: Background function: "chebyschev" function with 24 terms:
4846.854, -11028.729, -20160.862, 256317.539, 592987.724,
-5.249158441e6, -3.631253229e6, 4.6716624983e7, 2.478157997e6,
-2.22566966249e8, 5.3300222852e7, 6.38125053237e8, -2.55142761173e8,
-1.156971410908e9, 5.82828782201e8, 1.333696204767e9, -7.80463244314e8,
-9.38678820304e8, 6.25995183217e8, 3.54965933309e8, -2.79499578917e8,
-4.3505635500e7, 5.3561337350e7, -6.779782588e6, |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
H1 | 0.73437 | 0.64832 | 0.61697 | 0.010* | |
H3 | 0.62066 | 0.52561 | 0.48475 | 0.010* | |
H5 | 0.63637 | 0.70515 | 0.70368 | 0.010* | |
H7 | 0.39286 | 0.75947 | 0.76895 | 0.010* | |
H9 | 0.56380 | 0.71649 | 1.02060 | 0.010* | |
H11 | 0.57257 | 0.86694 | 0.60450 | 0.010* | |
H13 | 0.67816 | 0.42391 | 0.32840 | 0.010* | |
H15 | 0.78138 | 0.35187 | 0.24815 | 0.010* | |
C1 | 0.82279 | 0.46783 | 0.40575 | 0.010* | |
C3 | 0.74039 | 0.52654 | 0.46840 | 0.010* | |
C5 | 0.72384 | 0.44947 | 0.36647 | 0.010* | |
C7 | 0.70785 | 0.59186 | 0.54957 | 0.010* | |
C9 | 0.64674 | 0.58407 | 0.54803 | 0.010* | |
C11 | 0.61283 | 0.64767 | 0.63013 | 0.010* | |
C13 | 0.45912 | 0.67848 | 0.67324 | 0.010* | |
C15 | 0.48324 | 0.81449 | 0.82113 | 0.010* | |
C17 | 0.54189 | 0.77530 | 0.78740 | 0.010* | |
C19 | 0.77679 | 0.41206 | 0.32570 | 0.010* | |
N1 | 0.55450 | 0.63368 | 0.61499 | 0.010* | |
N3 | 0.52151 | 0.69179 | 0.69055 | 0.010* | |
N5 | 0.43833 | 0.75280 | 0.75654 | 0.010* | |
N7 | 0.88518 | 0.46110 | 0.41877 | 0.010* | |
O1 | 0.80179 | 0.53803 | 0.49165 | 0.010* | |
O3 | 0.90364 | 0.39190 | 0.35136 | 0.010* | |
O5 | 0.91767 | 0.52278 | 0.49571 | 0.010* | |
O7 | 0.42825 | 0.61607 | 0.60001 | 0.010* | |
O9 | 0.47708 | 0.88773 | 0.89374 | 0.010* | |
H17 | 0.04669 | 0.90902 | 0.96963 | 0.010* | |
H19 | 0.10363 | 0.76403 | 0.75563 | 0.010* | |
H21 | 0.15591 | 0.92637 | 0.99388 | 0.010* | |
H23 | 0.40287 | 0.90144 | 0.95446 | 0.010* | |
H25 | 0.24945 | 1.06139 | 0.86481 | 0.010* | |
H27 | 0.24527 | 0.90839 | 1.27639 | 0.010* | |
H29 | 0.00265 | 0.69269 | 0.64518 | 0.010* | |
H31 | −0.11852 | 0.68967 | 0.59237 | 0.010* | |
C21 | −0.10609 | 0.80451 | 0.77935 | 0.010* | |
C23 | −0.00865 | 0.81021 | 0.81570 | 0.010* | |
C25 | −0.02653 | 0.73908 | 0.69938 | 0.010* | |
C27 | 0.04779 | 0.85095 | 0.88210 | 0.010* | |
C29 | 0.10147 | 0.82288 | 0.84010 | 0.010* | |
C31 | 0.15694 | 0.86719 | 0.90797 | 0.010* | |
C33 | 0.31258 | 0.84759 | 0.89330 | 0.010* | |
C35 | 0.33497 | 0.98019 | 1.05233 | 0.010* | |
C37 | 0.26695 | 0.96216 | 1.03632 | 0.010* | |
C39 | −0.08910 | 0.73637 | 0.67384 | 0.010* | |
N9 | 0.20693 | 0.83653 | 0.86463 | 0.010* | |
N11 | 0.25843 | 0.88000 | 0.92881 | 0.010* | |
N13 | 0.35739 | 0.90881 | 0.96795 | 0.010* | |
N15 | −0.16289 | 0.83235 | 0.80984 | 0.010* | |
O11 | −0.05809 | 0.84979 | 0.86689 | 0.010* | |
O13 | −0.20670 | 0.79634 | 0.71446 | 0.010* | |
O15 | −0.16667 | 0.89097 | 0.92750 | 0.010* | |
O17 | 0.31939 | 0.77775 | 0.81175 | 0.010* | |
O19 | 0.36417 | 1.04487 | 1.12393 | 0.010* | |
Geometric parameters (Å, º) top
H1—C7 | 1.0828 | H17—C27 | 1.0853 |
H3—C9 | 1.0830 | H19—C29 | 1.0841 |
H5—C11 | 1.09 | H21—C31 | 1.0910 |
H7—N5 | 1.0308 | H23—O9 | 1.7392 |
H7—O17 | 1.7172 | H23—N13 | 1.0341 |
H9—C17 | 1.1006 | H25—C37 | 1.0961 |
H11—C17 | 1.0844 | H27—C37 | 1.0928 |
H13—C5 | 1.0744 | H29—C25 | 1.0773 |
H15—C19 | 1.0787 | H31—C39 | 1.0754 |
C1—C19 | 1.3678 | C21—C39 | 1.3734 |
C1—N7 | 1.3937 | C21—N15 | 1.3908 |
C1—O1 | 1.3512 | C21—O11 | 1.3466 |
C3—C5 | 1.3838 | C23—C25 | 1.3853 |
C3—C7 | 1.4127 | C23—C27 | 1.4084 |
C3—O1 | 1.3605 | C23—O11 | 1.3616 |
C5—H13 | 1.0744 | C25—H29 | 1.0773 |
C5—C3 | 1.3838 | C25—C23 | 1.3853 |
C5—C19 | 1.3905 | C25—C39 | 1.3877 |
C7—H1 | 1.0828 | C27—H17 | 1.0853 |
C7—C3 | 1.4127 | C27—C23 | 1.4084 |
C7—C9 | 1.3468 | C27—C29 | 1.3479 |
C9—H3 | 1.0830 | C29—H19 | 1.0841 |
C9—C7 | 1.3468 | C29—C27 | 1.3479 |
C9—C11 | 1.4167 | C29—C31 | 1.4134 |
C11—H5 | 1.09 | C31—H21 | 1.0910 |
C11—C9 | 1.4167 | C31—C29 | 1.4134 |
C11—N1 | 1.2898 | C31—N9 | 1.2920 |
C13—N3 | 1.3792 | C33—N11 | 1.3716 |
C13—N5 | 1.3858 | C33—N13 | 1.3760 |
C13—O7 | 1.2081 | C33—O17 | 1.2221 |
C15—C17 | 1.5026 | C35—C37 | 1.5041 |
C15—N5 | 1.3494 | C35—N13 | 1.3727 |
C15—O9 | 1.2217 | C35—O19 | 1.2075 |
C17—H9 | 1.1006 | C37—H25 | 1.0961 |
C17—H11 | 1.0844 | C37—H27 | 1.0928 |
C17—C15 | 1.5026 | C37—C35 | 1.5041 |
C17—N3 | 1.4510 | C37—N11 | 1.4511 |
C19—H15 | 1.0787 | C39—H31 | 1.0754 |
C19—C1 | 1.3678 | C39—C21 | 1.3734 |
C19—C5 | 1.3905 | C39—C25 | 1.3877 |
N1—C11 | 1.2898 | N9—C31 | 1.2920 |
N1—N3 | 1.3241 | N9—N11 | 1.3284 |
N3—C13 | 1.3792 | N11—C33 | 1.3716 |
N3—C17 | 1.4510 | N11—C37 | 1.4511 |
N3—N1 | 1.3241 | N11—N9 | 1.3284 |
N5—H7 | 1.0308 | N13—H23 | 1.0341 |
N5—C13 | 1.3858 | N13—C33 | 1.3760 |
N5—C15 | 1.3494 | N13—C35 | 1.3727 |
N7—C1 | 1.3937 | N15—C21 | 1.3908 |
N7—O3 | 1.2415 | N15—O13 | 1.2424 |
N7—O5 | 1.2322 | N15—O15 | 1.2390 |
O1—C1 | 1.3512 | O11—C21 | 1.3466 |
O1—C3 | 1.3605 | O11—C23 | 1.3616 |
O3—N7 | 1.2415 | O13—N15 | 1.2424 |
O5—N7 | 1.2322 | O15—N15 | 1.2390 |
O7—C13 | 1.2081 | O17—H7 | 1.7172 |
O9—C15 | 1.2217 | O17—C33 | 1.2221 |
O9—H23 | 1.7392 | O19—C35 | 1.2075 |
| | | |
C19—C1—N7 | 131.106 | C39—C21—N15 | 131.144 |
C19—C1—O1 | 111.839 | C39—C21—O11 | 111.9 |
N7—C1—O1 | 117.038 | N15—C21—O11 | 116.955 |
C5—C3—C7 | 134.101 | C25—C23—C27 | 134.363 |
C5—C3—O1 | 109.435 | C25—C23—O11 | 109.899 |
C7—C3—O1 | 116.464 | C27—C23—O11 | 115.72 |
H13—C5—C3 | 125.354 | H29—C25—C23 | 126.248 |
H13—C5—C19 | 127.272 | H29—C25—C39 | 126.794 |
C3—C5—C19 | 107.374 | C23—C25—C39 | 106.941 |
H1—C7—C3 | 116.82 | H17—C27—C23 | 116.428 |
H1—C7—C9 | 120.819 | H17—C27—C29 | 119.78 |
C3—C7—C9 | 122.356 | C23—C27—C29 | 123.789 |
H3—C9—C7 | 120.134 | H19—C29—C27 | 121.082 |
H3—C9—C11 | 116.188 | H19—C29—C31 | 117.375 |
C7—C9—C11 | 123.672 | C27—C29—C31 | 121.539 |
H5—C11—C9 | 119.676 | H21—C31—C29 | 118.714 |
H5—C11—N1 | 122.828 | H21—C31—N9 | 122.561 |
C9—C11—N1 | 117.495 | C29—C31—N9 | 118.725 |
N3—C13—N5 | 105.705 | N11—C33—N13 | 106.558 |
N3—C13—O7 | 127.975 | N11—C33—O17 | 126.455 |
N5—C13—O7 | 126.319 | N13—C33—O17 | 126.987 |
C17—C15—N5 | 106.775 | C37—C35—N13 | 106.3 |
C17—C15—O9 | 126.879 | C37—C35—O19 | 126.98 |
N5—C15—O9 | 126.346 | N13—C35—O19 | 126.719 |
H9—C17—H11 | 109.402 | H25—C37—H27 | 108.787 |
H9—C17—C15 | 110.123 | H25—C37—C35 | 112.057 |
H11—C17—C15 | 110.441 | H27—C37—C35 | 109.642 |
H9—C17—N3 | 112.349 | H25—C37—N11 | 111.487 |
H11—C17—N3 | 112.096 | H27—C37—N11 | 112.44 |
C15—C17—N3 | 102.255 | C35—C37—N11 | 102.349 |
H15—C19—C1 | 126.564 | H31—C39—C21 | 126.816 |
H15—C19—C5 | 128.088 | H31—C39—C25 | 127.654 |
C1—C19—C5 | 105.348 | C21—C39—C25 | 105.524 |
C11—N1—N3 | 118.95 | C31—N9—N11 | 117.485 |
C13—N3—C17 | 111.706 | C33—N11—C37 | 111.818 |
C13—N3—N1 | 119.565 | C33—N11—N9 | 119.72 |
C17—N3—N1 | 128.71 | C37—N11—N9 | 128.461 |
H7—N5—C13 | 122.941 | H23—N13—C33 | 121.648 |
H7—N5—C15 | 123.529 | H23—N13—C35 | 125.396 |
C13—N5—C15 | 113.529 | C33—N13—C35 | 112.943 |
C1—N7—O3 | 116.476 | C21—N15—O13 | 116.843 |
C1—N7—O5 | 118.547 | C21—N15—O15 | 118.694 |
O3—N7—O5 | 124.977 | O13—N15—O15 | 124.462 |
C1—O1—C3 | 106.003 | C21—O11—C23 | 105.729 |
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