Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S010827010403046X/dn1069sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S010827010403046X/dn1069Isup2.hkl |
CCDC reference: 263058
Recrystallization was carried out from acetone, benzene/acetone, methylene chloride/acetone and carbon tetrachloride/acetone. The first three gave similar crystals; the last gave crystals of a distinctly different platy habit, but all proved to have the same cell dimensions.
In order to simplify the discussion of the pseudosymmetry and to make the molecular chains lie parallel to an axis, the conventional unit cell [a = 10.604 (3) Å, b = 11.826 (3) Å, c = 18.005 (5) Å, α = 103.10 (1)°, β = 100.23 (1)° and γ = 109.80 (1)°] was converted by the matrix 110/112/100 to the cell in C1 reported in the experimental data.
Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 1997); program(s) used to refine structure: SHELXTL; molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and SHELXTL; software used to prepare material for publication: SHELXTL.
C13H9NO | Z = 16 |
Mr = 195.21 | F(000) = 1632 |
Triclinic, C1 | Dx = 1.305 Mg m−3 |
Hall symbol: -C 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 12.936 (3) Å | Cell parameters from 3725 reflections |
b = 33.696 (8) Å | θ = 2.5–27.5° |
c = 10.604 (3) Å | µ = 0.08 mm−1 |
α = 90.35 (1)° | T = 174 K |
β = 120.67 (1)° | Elongated octahedron, colorless |
γ = 89.60 (1)° | 0.50 × 0.35 × 0.30 mm |
V = 3975.5 (17) Å3 |
Siemens SMART area detector diffractometer | 6872 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.025 |
Graphite monochromator | θmax = 27.0°, θmin = 1.2° |
ω scans | h = −16→16 |
22798 measured reflections | k = −42→42 |
8628 independent reflections | l = −13→13 |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.055 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.119 | w = 1/[σ2(Fo2) + (0.023P)2 + 4.96P] where P = (Fo2 + 2Fc2)/3 |
S = 1.12 | (Δ/σ)max = 0.014 |
8628 reflections | Δρmax = 0.20 e Å−3 |
558 parameters | Δρmin = −0.16 e Å−3 |
0 restraints | Extinction correction: SHELXTL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.00031 (6) |
C13H9NO | γ = 89.60 (1)° |
Mr = 195.21 | V = 3975.5 (17) Å3 |
Triclinic, C1 | Z = 16 |
a = 12.936 (3) Å | Mo Kα radiation |
b = 33.696 (8) Å | µ = 0.08 mm−1 |
c = 10.604 (3) Å | T = 174 K |
α = 90.35 (1)° | 0.50 × 0.35 × 0.30 mm |
β = 120.67 (1)° |
Siemens SMART area detector diffractometer | 6872 reflections with I > 2σ(I) |
22798 measured reflections | Rint = 0.025 |
8628 independent reflections |
R[F2 > 2σ(F2)] = 0.055 | 0 restraints |
wR(F2) = 0.119 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.12 | Δρmax = 0.20 e Å−3 |
8628 reflections | Δρmin = −0.16 e Å−3 |
558 parameters |
Geometry. The pseudosymmetry operations A→B screw axis parallel to b x(B) = 1.330 (4) − x(A) y(B) = 0.125 (2) + y(A) z(B) = 0.242 (8) − z(A) A→C glide plane perpendicular to a x(C) = 1.202 (3) − x(A) + z(A)sin β y(C) = 0.250 (2) + y(A) z(C) = 0.499 (5) + z(A) A→D glide plane parallel to ab x(D) = 0.168 (6) + x(A) − z(A)sin β y(D) = 0.376 (1) + y(A) z(D) = 0.741 (8) − z(A) A→B' glide plane perpendicular to b x(B') = 0.170 (4) + x(A) y(B') = 0.375 (2) − y(A) z(B') = 0.758 (8) + z(A) A→C' screw axis parallel to a x(C') = 0.298 (3) + x(A) −z(A)sin β y(C') = 0.250 (2) − y(A) z(C') = 0.501 (5) − z(A) A→D' screw axis perpendicular to ab x(D') = 1.332 (5)) − x(A) +z(A)sin β y(D') = 0.124 (1) − y(A) z(D') = 0.259 (8) + z(A) ——————————————————————- B→A screw axis parallel to b x(A) = 1.330 (4) − x(B) y(A) = −0.125 (2) + y(B) z(A) = 0.242 (8) − z(B) B→C glide plane parallel to ab x(C) = 0.080 (4) + x(B) − z(B)sin β y(C) = 0.125 (1) + y(B) z(C) = 0.741 (5) − z(B) B→D glide plane perpendicular to a x(D) = 1.290 (3) − x(B) + z(B)sin β y(D) = 0.251 (1) + y(B) z(D) = 0.500 (3) + z(B) B→A' glide plane perpendicular to b x(A') = 0.170 (4) + x(B) y(A') = 0.625 (2) − y(B) z(A') = 0.758 (8) + z(B) B→C' screw axis perpendicular to ab x(C') = 1.420 (4) − x(B) + z(B)sin β y(C') = 0.375 (1) − y(B) z(C') = 0.259 (5) + z(B) B→D' screw axis parallel to a x(D') = 0.210 (3) + x(B) − z(B)sin β y(D') = 0.249 (1) − y(B) z(D') = 0.500 (3) − z(B) ——————————————————————- C→A glide plane perpendicular to a x(A) = 0.773 (2) − x(C) + z(C)sin β y(A) = −0.250 (2) + y(C) z(A) = −0.499 (5) + z(C) C→B glide plane parallel to ab x(B) = 0.558 (3) + x(C) − z(C)sin β y(B) = −0.125 (1) + y(C) z(B) = 0.741 (5) − z(C) C→D screw axis parallel to b x(D) = 1.370 (4) − x(C) y(D) = 0.126 (2) + y(C) z(D) = 1.241 (4) − z(C) C→A' screw axis parallel to a x(A') = 0.727 (2) + x(C) − z(C)sin β y(A') = 0.750 (2) − y(C) z(A') = 1.499 (5) − z(C) C→B' screw axis perpendicular to ab x(B') = 0.943 (3) − x(C) + z(C)sin β y(B') = 0.625 (1) − y(C) z(B') = 0.259 (5) + z(C) C→D' glide plane perpendicular to b x(D') = 0.130 (4) + x(C) y(D') = 0.374 (1) − y(C) z(D') = −0.241 (5) + z(C) —————————————————————— D→A glide plane parallel to ab x(A) = 0.470 (2) + x(D) − z(D)sin β y(A) = −0.376 (1) + y(D) z(A) = 0.741 (8) − z(D) D→B glide plane perpendicular to a x(B) = 0.861 (4) − x(D) + z(D)sin β y(B) = −0.251 (1) + y(D) z(B) = −0.500 (3) + z(D) D→C screw axis parallel to b x(C) = 1.370 (4) − x(D) y(C) = −0.126 (2) + y(D) z(C) = 1.241 (4) − z(D) D→A' screw axis perpendicular to ab x(A') = 1.030 (2) − x(D) + z(D)sin β y(A') = 0.876 (1) − y(D) z(A') = 0.259 (8) + z(D) D→B' screw axis parallel to a x(B') = 0.639 (4) + x(D) − z(D)sin β y(B') = 0.751 (1) − y(D) z(B') = 1.500 (3) − z(D) D→C' glide plane perpendicular to b x(C') = 0.130 (4) + x(D) y(C') = 0.626 (2) − y(D) z(C') = −0.241 (4) + z(D) |
x | y | z | Uiso*/Ueq | ||
C1A | 0.98745 (17) | 0.12082 (6) | 0.0517 (2) | 0.0366 (4) | |
C2A | 0.94088 (19) | 0.08990 (6) | 0.0936 (2) | 0.0447 (5) | |
H2A | 0.9881 | 0.0669 | 0.1388 | 0.054* | |
C3A | 0.82539 (18) | 0.09281 (6) | 0.0692 (2) | 0.0411 (5) | |
H3A | 0.7943 | 0.0717 | 0.0988 | 0.049* | |
C4A | 0.75349 (16) | 0.12605 (5) | 0.0022 (2) | 0.0310 (4) | |
C5A | 0.80250 (17) | 0.15683 (5) | −0.0392 (2) | 0.0350 (4) | |
H5A | 0.7552 | 0.1797 | −0.0854 | 0.042* | |
C6A | 0.91787 (18) | 0.15447 (6) | −0.0143 (2) | 0.0383 (4) | |
H6A | 0.9498 | 0.1758 | −0.0420 | 0.046* | |
C7A | 0.62863 (16) | 0.12885 (5) | −0.0268 (2) | 0.0308 (4) | |
C8A | 0.59531 (17) | 0.11127 (5) | 0.0666 (2) | 0.0320 (4) | |
H8A | 0.6539 | 0.0971 | 0.1502 | 0.038* | |
C9A | 0.47871 (17) | 0.11411 (5) | 0.0399 (2) | 0.0334 (4) | |
H9A | 0.4581 | 0.1020 | 0.1049 | 0.040* | |
C10A | 0.39205 (16) | 0.13470 (5) | −0.0823 (2) | 0.0336 (4) | |
C11A | 0.42366 (17) | 0.15250 (6) | −0.1756 (2) | 0.0360 (4) | |
H11A | 0.3650 | 0.1667 | −0.2589 | 0.043* | |
C12A | 0.53984 (17) | 0.14960 (5) | −0.1480 (2) | 0.0344 (4) | |
H12A | 0.5600 | 0.1620 | −0.2128 | 0.041* | |
C13A | 1.10525 (19) | 0.11767 (6) | 0.0696 (2) | 0.0422 (5) | |
N14A | 1.19775 (17) | 0.11542 (6) | 0.0797 (2) | 0.0544 (5) | |
O15A | 0.27569 (13) | 0.13834 (5) | −0.11598 (17) | 0.0448 (4) | |
H15A | 0.258 (3) | 0.1273 (9) | −0.053 (3) | 0.080 (10)* | |
C1B | 0.34477 (17) | 0.24397 (6) | 0.1938 (2) | 0.0357 (4) | |
C2B | 0.39675 (18) | 0.21186 (6) | 0.1629 (2) | 0.0374 (4) | |
H2B | 0.3544 | 0.1876 | 0.1287 | 0.045* | |
C3B | 0.51035 (17) | 0.21554 (6) | 0.1823 (2) | 0.0342 (4) | |
H3B | 0.5450 | 0.1937 | 0.1598 | 0.041* | |
C4B | 0.57512 (16) | 0.25072 (5) | 0.23438 (19) | 0.0298 (4) | |
C5B | 0.52048 (17) | 0.28283 (6) | 0.2635 (2) | 0.0350 (4) | |
H5B | 0.5629 | 0.3071 | 0.2979 | 0.042* | |
C6B | 0.40679 (18) | 0.27986 (6) | 0.2432 (2) | 0.0383 (4) | |
H6B | 0.3709 | 0.3019 | 0.2626 | 0.046* | |
C7B | 0.69957 (16) | 0.25411 (5) | 0.2629 (2) | 0.0301 (4) | |
C8B | 0.73681 (18) | 0.23553 (5) | 0.1745 (2) | 0.0346 (4) | |
H8B | 0.6810 | 0.2201 | 0.0929 | 0.042* | |
C9B | 0.85427 (18) | 0.23923 (6) | 0.2039 (2) | 0.0359 (4) | |
H9B | 0.8774 | 0.2270 | 0.1411 | 0.043* | |
C10B | 0.93750 (17) | 0.26085 (5) | 0.3250 (2) | 0.0345 (4) | |
C11B | 0.90259 (18) | 0.27900 (5) | 0.4155 (2) | 0.0356 (4) | |
H11B | 0.9593 | 0.2937 | 0.4989 | 0.043* | |
C12B | 0.78543 (17) | 0.27570 (5) | 0.3841 (2) | 0.0334 (4) | |
H12B | 0.7625 | 0.2884 | 0.4463 | 0.040* | |
C13B | 0.22787 (19) | 0.24024 (6) | 0.1782 (2) | 0.0412 (5) | |
N14B | 0.13566 (17) | 0.23775 (6) | 0.1682 (2) | 0.0517 (5) | |
O15B | 1.05447 (13) | 0.26516 (5) | 0.36076 (18) | 0.0464 (4) | |
H15B | 1.070 (3) | 0.2544 (9) | 0.292 (3) | 0.082 (10)* | |
C1C | 0.25715 (17) | 0.36860 (6) | 0.5480 (2) | 0.0362 (4) | |
C2C | 0.33740 (19) | 0.33700 (6) | 0.5826 (2) | 0.0435 (5) | |
H2C | 0.3262 | 0.3131 | 0.6211 | 0.052* | |
C3C | 0.43298 (19) | 0.34073 (6) | 0.5603 (2) | 0.0408 (5) | |
H3C | 0.4881 | 0.3193 | 0.5855 | 0.049* | |
C4C | 0.45071 (17) | 0.37520 (5) | 0.5019 (2) | 0.0334 (4) | |
C5C | 0.36890 (18) | 0.40654 (6) | 0.4672 (2) | 0.0374 (4) | |
H5C | 0.3792 | 0.4303 | 0.4271 | 0.045* | |
C6C | 0.27332 (18) | 0.40338 (6) | 0.4904 (2) | 0.0385 (5) | |
H6C | 0.2189 | 0.4249 | 0.4671 | 0.046* | |
C7C | 0.55200 (17) | 0.37875 (5) | 0.4750 (2) | 0.0320 (4) | |
C8C | 0.66464 (17) | 0.36213 (6) | 0.5691 (2) | 0.0353 (4) | |
H8C | 0.6772 | 0.3480 | 0.6530 | 0.042* | |
C9C | 0.75901 (18) | 0.36586 (6) | 0.5428 (2) | 0.0365 (4) | |
H9C | 0.8353 | 0.3545 | 0.6088 | 0.044* | |
C10C | 0.74152 (17) | 0.38616 (6) | 0.4201 (2) | 0.0357 (4) | |
C11C | 0.63037 (18) | 0.40299 (6) | 0.3251 (2) | 0.0378 (4) | |
H11C | 0.6182 | 0.4170 | 0.2410 | 0.045* | |
C12C | 0.53746 (18) | 0.39950 (5) | 0.3524 (2) | 0.0355 (4) | |
H12C | 0.4620 | 0.4114 | 0.2869 | 0.043* | |
C13C | 0.15359 (19) | 0.36513 (6) | 0.5643 (2) | 0.0412 (5) | |
N14C | 0.06959 (17) | 0.36321 (6) | 0.5746 (2) | 0.0514 (5) | |
O15C | 0.83044 (14) | 0.39063 (5) | 0.38768 (18) | 0.0475 (4) | |
H15C | 0.900 (2) | 0.3789 (8) | 0.457 (3) | 0.072 (9)* | |
C1D | 1.11473 (18) | 0.49599 (6) | 0.6949 (2) | 0.0392 (5) | |
C2D | 1.03733 (19) | 0.46372 (6) | 0.6595 (2) | 0.0422 (5) | |
H2D | 1.0521 | 0.4398 | 0.6231 | 0.051* | |
C3D | 0.93916 (18) | 0.46674 (6) | 0.6778 (2) | 0.0391 (5) | |
H3D | 0.8862 | 0.4448 | 0.6523 | 0.047* | |
C4D | 0.91615 (17) | 0.50113 (5) | 0.7327 (2) | 0.0340 (4) | |
C5D | 0.99403 (18) | 0.53363 (6) | 0.7654 (2) | 0.0384 (5) | |
H5D | 0.9789 | 0.5576 | 0.8010 | 0.046* | |
C6D | 1.09171 (18) | 0.53120 (6) | 0.7465 (2) | 0.0407 (5) | |
H6D | 1.1431 | 0.5534 | 0.7685 | 0.049* | |
C7D | 0.81565 (17) | 0.50391 (5) | 0.7615 (2) | 0.0341 (4) | |
C8D | 0.70321 (18) | 0.48708 (6) | 0.6693 (2) | 0.0383 (4) | |
H8D | 0.6897 | 0.4727 | 0.5849 | 0.046* | |
C9D | 0.61057 (18) | 0.49103 (6) | 0.6988 (2) | 0.0421 (5) | |
H9D | 0.5342 | 0.4797 | 0.6343 | 0.050* | |
C10D | 0.62971 (19) | 0.51157 (6) | 0.8228 (2) | 0.0402 (5) | |
C11D | 0.74151 (19) | 0.52809 (6) | 0.9170 (2) | 0.0416 (5) | |
H11D | 0.7551 | 0.5420 | 1.0023 | 0.050* | |
C12D | 0.83264 (18) | 0.52422 (6) | 0.8864 (2) | 0.0396 (5) | |
H12D | 0.9088 | 0.5356 | 0.9516 | 0.047* | |
C13D | 1.2198 (2) | 0.49270 (7) | 0.6818 (2) | 0.0461 (5) | |
N14D | 1.30501 (19) | 0.49029 (6) | 0.6741 (2) | 0.0592 (5) | |
O15D | 0.54339 (16) | 0.51658 (5) | 0.8601 (2) | 0.0536 (4) | |
H15D | 0.471 (2) | 0.5073 (7) | 0.784 (3) | 0.058 (8)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1A | 0.0357 (10) | 0.0432 (11) | 0.0328 (10) | −0.0024 (8) | 0.0189 (9) | −0.0040 (8) |
C2A | 0.0409 (12) | 0.0405 (12) | 0.0521 (13) | 0.0063 (9) | 0.0233 (10) | 0.0112 (10) |
C3A | 0.0393 (11) | 0.0358 (11) | 0.0481 (12) | 0.0008 (9) | 0.0221 (10) | 0.0112 (9) |
C4A | 0.0353 (10) | 0.0283 (9) | 0.0290 (9) | −0.0036 (7) | 0.0160 (8) | −0.0011 (7) |
C5A | 0.0408 (11) | 0.0282 (10) | 0.0359 (10) | 0.0000 (8) | 0.0195 (9) | 0.0033 (8) |
C6A | 0.0441 (12) | 0.0361 (11) | 0.0406 (11) | −0.0055 (9) | 0.0259 (10) | 0.0011 (8) |
C7A | 0.0338 (10) | 0.0244 (9) | 0.0315 (9) | −0.0034 (7) | 0.0148 (8) | −0.0030 (7) |
C8A | 0.0355 (10) | 0.0275 (9) | 0.0291 (9) | −0.0017 (7) | 0.0135 (8) | 0.0011 (7) |
C9A | 0.0392 (10) | 0.0293 (9) | 0.0336 (10) | −0.0056 (8) | 0.0198 (9) | −0.0035 (8) |
C10A | 0.0319 (10) | 0.0306 (10) | 0.0347 (10) | −0.0019 (8) | 0.0145 (8) | −0.0077 (8) |
C11A | 0.0375 (11) | 0.0333 (10) | 0.0311 (10) | 0.0031 (8) | 0.0131 (8) | 0.0021 (8) |
C12A | 0.0404 (11) | 0.0298 (10) | 0.0322 (10) | −0.0016 (8) | 0.0179 (9) | 0.0026 (8) |
C13A | 0.0416 (12) | 0.0488 (12) | 0.0371 (11) | −0.0026 (9) | 0.0208 (9) | −0.0047 (9) |
N14A | 0.0443 (11) | 0.0699 (14) | 0.0553 (12) | −0.0017 (9) | 0.0300 (10) | −0.0078 (10) |
O15A | 0.0351 (8) | 0.0503 (9) | 0.0484 (9) | 0.0033 (6) | 0.0209 (7) | −0.0002 (7) |
C1B | 0.0341 (10) | 0.0423 (11) | 0.0310 (10) | 0.0018 (8) | 0.0168 (8) | 0.0053 (8) |
C2B | 0.0400 (11) | 0.0349 (10) | 0.0356 (10) | −0.0060 (8) | 0.0180 (9) | −0.0033 (8) |
C3B | 0.0394 (11) | 0.0298 (10) | 0.0338 (10) | 0.0014 (8) | 0.0189 (9) | −0.0016 (8) |
C4B | 0.0369 (10) | 0.0288 (9) | 0.0236 (9) | 0.0013 (7) | 0.0152 (8) | 0.0034 (7) |
C5B | 0.0403 (11) | 0.0275 (9) | 0.0386 (11) | −0.0006 (8) | 0.0211 (9) | −0.0007 (8) |
C6B | 0.0434 (11) | 0.0344 (10) | 0.0402 (11) | 0.0060 (8) | 0.0236 (9) | 0.0020 (8) |
C7B | 0.0365 (10) | 0.0237 (9) | 0.0305 (9) | 0.0023 (7) | 0.0174 (8) | 0.0049 (7) |
C8B | 0.0415 (11) | 0.0291 (9) | 0.0331 (10) | 0.0012 (8) | 0.0189 (9) | 0.0001 (8) |
C9B | 0.0440 (11) | 0.0327 (10) | 0.0373 (10) | 0.0077 (8) | 0.0253 (9) | 0.0037 (8) |
C10B | 0.0363 (10) | 0.0299 (10) | 0.0387 (11) | 0.0048 (8) | 0.0201 (9) | 0.0112 (8) |
C11B | 0.0398 (11) | 0.0303 (10) | 0.0349 (10) | −0.0034 (8) | 0.0177 (9) | 0.0016 (8) |
C12B | 0.0415 (11) | 0.0293 (9) | 0.0338 (10) | −0.0013 (8) | 0.0225 (9) | −0.0016 (8) |
C13B | 0.0424 (12) | 0.0468 (12) | 0.0362 (11) | 0.0012 (9) | 0.0214 (9) | 0.0052 (9) |
N14B | 0.0456 (11) | 0.0622 (13) | 0.0556 (12) | 0.0006 (9) | 0.0319 (10) | 0.0094 (10) |
O15B | 0.0388 (8) | 0.0493 (9) | 0.0558 (10) | 0.0033 (7) | 0.0276 (8) | 0.0082 (7) |
C1C | 0.0354 (10) | 0.0372 (11) | 0.0319 (10) | −0.0002 (8) | 0.0143 (8) | −0.0019 (8) |
C2C | 0.0508 (13) | 0.0361 (11) | 0.0465 (12) | 0.0063 (9) | 0.0268 (10) | 0.0115 (9) |
C3C | 0.0461 (12) | 0.0348 (11) | 0.0436 (11) | 0.0125 (9) | 0.0245 (10) | 0.0107 (9) |
C4C | 0.0368 (10) | 0.0302 (10) | 0.0282 (9) | 0.0024 (8) | 0.0131 (8) | −0.0003 (7) |
C5C | 0.0411 (11) | 0.0271 (10) | 0.0406 (11) | 0.0015 (8) | 0.0183 (9) | 0.0025 (8) |
C6C | 0.0364 (11) | 0.0312 (10) | 0.0415 (11) | 0.0043 (8) | 0.0152 (9) | −0.0001 (8) |
C7C | 0.0370 (10) | 0.0270 (9) | 0.0287 (9) | 0.0002 (7) | 0.0143 (8) | −0.0027 (7) |
C8C | 0.0411 (11) | 0.0323 (10) | 0.0285 (9) | 0.0029 (8) | 0.0149 (8) | 0.0020 (8) |
C9C | 0.0352 (10) | 0.0334 (10) | 0.0340 (10) | 0.0033 (8) | 0.0125 (8) | 0.0001 (8) |
C10C | 0.0373 (11) | 0.0316 (10) | 0.0375 (11) | −0.0058 (8) | 0.0187 (9) | −0.0053 (8) |
C11C | 0.0438 (11) | 0.0335 (10) | 0.0328 (10) | −0.0025 (8) | 0.0171 (9) | 0.0018 (8) |
C12C | 0.0379 (10) | 0.0291 (10) | 0.0334 (10) | 0.0023 (8) | 0.0137 (8) | 0.0032 (8) |
C13C | 0.0417 (12) | 0.0370 (11) | 0.0405 (11) | −0.0012 (9) | 0.0178 (10) | −0.0021 (9) |
N14C | 0.0429 (11) | 0.0485 (11) | 0.0644 (13) | −0.0035 (8) | 0.0284 (10) | −0.0051 (9) |
O15C | 0.0429 (9) | 0.0526 (9) | 0.0499 (9) | −0.0024 (7) | 0.0257 (8) | 0.0030 (7) |
C1D | 0.0397 (11) | 0.0404 (11) | 0.0342 (10) | −0.0015 (9) | 0.0164 (9) | 0.0006 (8) |
C2D | 0.0482 (12) | 0.0343 (11) | 0.0419 (12) | −0.0014 (9) | 0.0213 (10) | −0.0039 (9) |
C3D | 0.0450 (12) | 0.0286 (10) | 0.0392 (11) | −0.0054 (8) | 0.0183 (9) | −0.0020 (8) |
C4D | 0.0356 (10) | 0.0288 (9) | 0.0284 (9) | 0.0002 (8) | 0.0096 (8) | 0.0029 (7) |
C5D | 0.0421 (11) | 0.0287 (10) | 0.0394 (11) | −0.0024 (8) | 0.0170 (9) | −0.0033 (8) |
C6D | 0.0423 (11) | 0.0354 (11) | 0.0392 (11) | −0.0082 (9) | 0.0170 (9) | −0.0017 (8) |
C7D | 0.0369 (10) | 0.0253 (9) | 0.0335 (10) | 0.0007 (8) | 0.0132 (8) | 0.0053 (7) |
C8D | 0.0425 (11) | 0.0320 (10) | 0.0345 (10) | −0.0049 (8) | 0.0151 (9) | 0.0033 (8) |
C9D | 0.0374 (11) | 0.0369 (11) | 0.0421 (12) | −0.0046 (9) | 0.0130 (9) | 0.0075 (9) |
C10D | 0.0420 (11) | 0.0330 (10) | 0.0469 (12) | 0.0067 (8) | 0.0236 (10) | 0.0150 (9) |
C11D | 0.0477 (12) | 0.0359 (11) | 0.0389 (11) | 0.0055 (9) | 0.0204 (10) | 0.0034 (9) |
C12D | 0.0387 (11) | 0.0328 (10) | 0.0391 (11) | 0.0003 (8) | 0.0139 (9) | 0.0004 (8) |
C13D | 0.0477 (13) | 0.0460 (13) | 0.0431 (12) | −0.0033 (10) | 0.0220 (10) | −0.0014 (10) |
N14D | 0.0547 (13) | 0.0660 (14) | 0.0639 (14) | −0.0049 (10) | 0.0353 (11) | −0.0072 (11) |
O15D | 0.0501 (10) | 0.0534 (10) | 0.0644 (11) | 0.0050 (8) | 0.0342 (9) | 0.0120 (8) |
C1A—C2A | 1.391 (3) | C1C—C6C | 1.390 (3) |
C1A—C6A | 1.392 (3) | C1C—C2C | 1.395 (3) |
C1A—C13A | 1.439 (3) | C1C—C13C | 1.441 (3) |
C2A—C3A | 1.383 (3) | C2C—C3C | 1.378 (3) |
C2A—H2A | 0.9500 | C2C—H2C | 0.9500 |
C3A—C4A | 1.395 (3) | C3C—C4C | 1.394 (3) |
C3A—H3A | 0.9500 | C3C—H3C | 0.9500 |
C4A—C5A | 1.403 (2) | C4C—C5C | 1.401 (3) |
C4A—C7A | 1.485 (3) | C4C—C7C | 1.482 (3) |
C5A—C6A | 1.378 (3) | C5C—C6C | 1.383 (3) |
C5A—H5A | 0.9500 | C5C—H5C | 0.9500 |
C6A—H6A | 0.9500 | C6C—H6C | 0.9500 |
C7A—C12A | 1.398 (3) | C7C—C8C | 1.395 (3) |
C7A—C8A | 1.402 (3) | C7C—C12C | 1.405 (3) |
C8A—C9A | 1.388 (3) | C8C—C9C | 1.391 (3) |
C8A—H8A | 0.9500 | C8C—H8C | 0.9500 |
C9A—C10A | 1.391 (3) | C9C—C10C | 1.386 (3) |
C9A—H9A | 0.9500 | C9C—H9C | 0.9500 |
C10A—O15A | 1.363 (2) | C10C—O15C | 1.368 (2) |
C10A—C11A | 1.389 (3) | C10C—C11C | 1.386 (3) |
C11A—C12A | 1.379 (3) | C11C—C12C | 1.378 (3) |
C11A—H11A | 0.9500 | C11C—H11C | 0.9500 |
C12A—H12A | 0.9500 | C12C—H12C | 0.9500 |
C13A—N14A | 1.148 (3) | C13C—N14C | 1.148 (3) |
O15A—H15A | 0.89 (3) | O15C—H15C | 0.91 (3) |
C1B—C2B | 1.393 (3) | C1D—C2D | 1.397 (3) |
C1B—C6B | 1.399 (3) | C1D—C6D | 1.396 (3) |
C1B—C13B | 1.441 (3) | C1D—C13D | 1.439 (3) |
C2B—C3B | 1.382 (3) | C2D—C3D | 1.382 (3) |
C2B—H2B | 0.9500 | C2D—H2D | 0.9500 |
C3B—C4B | 1.395 (3) | C3D—C4D | 1.391 (3) |
C3B—H3B | 0.9500 | C3D—H3D | 0.9500 |
C4B—C5B | 1.405 (3) | C4D—C5D | 1.410 (3) |
C4B—C7B | 1.484 (3) | C4D—C7D | 1.481 (3) |
C5B—C6B | 1.378 (3) | C5D—C6D | 1.378 (3) |
C5B—H5B | 0.9500 | C5D—H5D | 0.9500 |
C6B—H6B | 0.9500 | C6D—H6D | 0.9500 |
C7B—C8B | 1.397 (3) | C7D—C8D | 1.396 (3) |
C7B—C12B | 1.399 (3) | C7D—C12D | 1.402 (3) |
C8B—C9B | 1.393 (3) | C8D—C9D | 1.390 (3) |
C8B—H8B | 0.9500 | C8D—H8D | 0.9500 |
C9B—C10B | 1.388 (3) | C9D—C10D | 1.388 (3) |
C9B—H9B | 0.9500 | C9D—H9D | 0.9500 |
C10B—O15B | 1.368 (2) | C10D—O15D | 1.371 (3) |
C10B—C11B | 1.390 (3) | C10D—C11D | 1.389 (3) |
C11B—C12B | 1.381 (3) | C11D—C12D | 1.378 (3) |
C11B—H11B | 0.9500 | C11D—H11D | 0.9500 |
C12B—H12B | 0.9500 | C12D—H12D | 0.9500 |
C13B—N14B | 1.146 (3) | C13D—N14D | 1.148 (3) |
O15B—H15B | 0.92 (3) | O15D—H15D | 0.92 (3) |
C2A—C1A—C6A | 119.95 (18) | C6C—C1C—C2C | 120.02 (19) |
C2A—C1A—C13A | 120.62 (19) | C6C—C1C—C13C | 119.01 (18) |
C6A—C1A—C13A | 119.37 (18) | C2C—C1C—C13C | 120.90 (19) |
C3A—C2A—C1A | 119.63 (19) | C3C—C2C—C1C | 119.49 (19) |
C3A—C2A—H2A | 120.2 | C3C—C2C—H2C | 120.3 |
C1A—C2A—H2A | 120.2 | C1C—C2C—H2C | 120.3 |
C2A—C3A—C4A | 121.53 (18) | C2C—C3C—C4C | 121.58 (18) |
C2A—C3A—H3A | 119.2 | C2C—C3C—H3C | 119.2 |
C4A—C3A—H3A | 119.2 | C4C—C3C—H3C | 119.2 |
C3A—C4A—C5A | 117.75 (17) | C3C—C4C—C5C | 118.11 (18) |
C3A—C4A—C7A | 121.56 (17) | C3C—C4C—C7C | 121.42 (17) |
C5A—C4A—C7A | 120.68 (17) | C5C—C4C—C7C | 120.46 (17) |
C6A—C5A—C4A | 121.31 (18) | C6C—C5C—C4C | 120.93 (18) |
C6A—C5A—H5A | 119.3 | C6C—C5C—H5C | 119.5 |
C4A—C5A—H5A | 119.3 | C4C—C5C—H5C | 119.5 |
C5A—C6A—C1A | 119.83 (18) | C5C—C6C—C1C | 119.87 (18) |
C5A—C6A—H6A | 120.1 | C5C—C6C—H6C | 120.1 |
C1A—C6A—H6A | 120.1 | C1C—C6C—H6C | 120.1 |
C12A—C7A—C8A | 117.37 (17) | C8C—C7C—C12C | 117.41 (18) |
C12A—C7A—C4A | 121.05 (17) | C8C—C7C—C4C | 122.05 (17) |
C8A—C7A—C4A | 121.58 (16) | C12C—C7C—C4C | 120.54 (17) |
C9A—C8A—C7A | 121.52 (17) | C9C—C8C—C7C | 121.39 (18) |
C9A—C8A—H8A | 119.2 | C9C—C8C—H8C | 119.3 |
C7A—C8A—H8A | 119.2 | C7C—C8C—H8C | 119.3 |
C8A—C9A—C10A | 119.77 (18) | C10C—C9C—C8C | 119.84 (18) |
C8A—C9A—H9A | 120.1 | C10C—C9C—H9C | 120.1 |
C10A—C9A—H9A | 120.1 | C8C—C9C—H9C | 120.1 |
O15A—C10A—C11A | 117.64 (18) | O15C—C10C—C11C | 117.57 (18) |
O15A—C10A—C9A | 122.88 (18) | O15C—C10C—C9C | 122.63 (18) |
C11A—C10A—C9A | 119.48 (18) | C11C—C10C—C9C | 119.80 (18) |
C12A—C11A—C10A | 120.34 (18) | C12C—C11C—C10C | 120.13 (18) |
C12A—C11A—H11A | 119.8 | C12C—C11C—H11C | 119.9 |
C10A—C11A—H11A | 119.8 | C10C—C11C—H11C | 119.9 |
C11A—C12A—C7A | 121.52 (18) | C11C—C12C—C7C | 121.42 (18) |
C11A—C12A—H12A | 119.2 | C11C—C12C—H12C | 119.3 |
C7A—C12A—H12A | 119.2 | C7C—C12C—H12C | 119.3 |
N14A—C13A—C1A | 178.0 (2) | N14C—C13C—C1C | 178.1 (2) |
C10A—O15A—H15A | 116.3 (19) | C10C—O15C—H15C | 110.6 (17) |
C2B—C1B—C6B | 120.23 (18) | C2D—C1D—C6D | 119.97 (19) |
C2B—C1B—C13B | 120.31 (19) | C2D—C1D—C13D | 120.14 (19) |
C6B—C1B—C13B | 119.45 (18) | C6D—C1D—C13D | 119.86 (19) |
C3B—C2B—C1B | 119.64 (18) | C3D—C2D—C1D | 119.61 (19) |
C3B—C2B—H2B | 120.2 | C3D—C2D—H2D | 120.2 |
C1B—C2B—H2B | 120.2 | C1D—C2D—H2D | 120.2 |
C2B—C3B—C4B | 121.28 (18) | C2D—C3D—C4D | 121.47 (19) |
C2B—C3B—H3B | 119.4 | C2D—C3D—H3D | 119.3 |
C4B—C3B—H3B | 119.4 | C4D—C3D—H3D | 119.3 |
C3B—C4B—C5B | 118.08 (17) | C3D—C4D—C5D | 118.10 (19) |
C3B—C4B—C7B | 121.45 (16) | C3D—C4D—C7D | 122.03 (17) |
C5B—C4B—C7B | 120.44 (16) | C5D—C4D—C7D | 119.84 (17) |
C6B—C5B—C4B | 121.45 (18) | C6D—C5D—C4D | 121.09 (18) |
C6B—C5B—H5B | 119.3 | C6D—C5D—H5D | 119.5 |
C4B—C5B—H5B | 119.3 | C4D—C5D—H5D | 119.5 |
C5B—C6B—C1B | 119.30 (18) | C5D—C6D—C1D | 119.72 (19) |
C5B—C6B—H6B | 120.4 | C5D—C6D—H6D | 120.1 |
C1B—C6B—H6B | 120.3 | C1D—C6D—H6D | 120.1 |
C8B—C7B—C12B | 117.50 (17) | C8D—C7D—C12D | 117.72 (19) |
C8B—C7B—C4B | 122.42 (17) | C8D—C7D—C4D | 122.90 (18) |
C12B—C7B—C4B | 120.06 (16) | C12D—C7D—C4D | 119.38 (17) |
C9B—C8B—C7B | 121.18 (18) | C9D—C8D—C7D | 121.06 (19) |
C9B—C8B—H8B | 119.4 | C9D—C8D—H8D | 119.5 |
C7B—C8B—H8B | 119.4 | C7D—C8D—H8D | 119.5 |
C10B—C9B—C8B | 120.00 (18) | C8D—C9D—C10D | 119.95 (19) |
C10B—C9B—H9B | 120.0 | C8D—C9D—H9D | 120.0 |
C8B—C9B—H9B | 120.0 | C10D—C9D—H9D | 120.0 |
O15B—C10B—C9B | 122.80 (18) | O15D—C10D—C11D | 116.6 (2) |
O15B—C10B—C11B | 117.58 (18) | O15D—C10D—C9D | 123.5 (2) |
C9B—C10B—C11B | 119.62 (18) | C11D—C10D—C9D | 119.85 (19) |
C12B—C11B—C10B | 119.93 (18) | C12D—C11D—C10D | 119.8 (2) |
C12B—C11B—H11B | 120.0 | C12D—C11D—H11D | 120.1 |
C10B—C11B—H11B | 120.0 | C10D—C11D—H11D | 120.1 |
C11B—C12B—C7B | 121.75 (17) | C11D—C12D—C7D | 121.60 (19) |
C11B—C12B—H12B | 119.1 | C11D—C12D—H12D | 119.2 |
C7B—C12B—H12B | 119.1 | C7D—C12D—H12D | 119.2 |
N14B—C13B—C1B | 178.6 (3) | N14D—C13D—C1D | 178.7 (3) |
C10B—O15B—H15B | 113.0 (18) | C10D—O15D—H15D | 108.8 (15) |
Experimental details
Crystal data | |
Chemical formula | C13H9NO |
Mr | 195.21 |
Crystal system, space group | Triclinic, C1 |
Temperature (K) | 174 |
a, b, c (Å) | 12.936 (3), 33.696 (8), 10.604 (3) |
α, β, γ (°) | 90.35 (1), 120.67 (1), 89.60 (1) |
V (Å3) | 3975.5 (17) |
Z | 16 |
Radiation type | Mo Kα |
µ (mm−1) | 0.08 |
Crystal size (mm) | 0.50 × 0.35 × 0.30 |
Data collection | |
Diffractometer | Siemens SMART area detector diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 22798, 8628, 6872 |
Rint | 0.025 |
(sin θ/λ)max (Å−1) | 0.639 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.055, 0.119, 1.12 |
No. of reflections | 8628 |
No. of parameters | 558 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.20, −0.16 |
Computer programs: SMART (Bruker, 2002), SAINT (Bruker, 2002), SAINT, SHELXTL (Sheldrick, 1997), ORTEP-3 for Windows (Farrugia, 1997) and SHELXTL.
H | N | O-H | O-H···N | H···N | H···N-C | O···N | ref |
H15A | N14Ai | 0.89 | 166 | 1.97 | 134 | 2.843 (2) | a |
H15B | N14Bii | 0.92 | 168 | 1.97 | 134 | 2.877 (2) | a |
H15C | N14Cii | 0.91 | 162 | 1.96 | 137 | 2.843 (2) | a |
H15D | N14Di | 0.92 | 161 | 1.94 | 139 | 2.828 (3) | a |
H1 | N2 | 0.91 | 167 | 1.92 | 174 | 2.820 (5) | b |
H6 | N1 | 0.88 | 170 | 1.97 | 166 | 2.839 (5) | b |
H9 | N8 | 0.94 | 174 | 1.91 | 170 | 2.847 (2) | c |
H1A | N21B | 0.92 | 173 | 1.88 | 170 | 2.795 (2) | d |
H1B | N21A | 0.91 | 172 | 1.90 | 158 | 2.798 (2) | d |
Symmetry codes: (i) −1 + x, y, z; (ii) 1 + x, y, z. a. 4-Hydroxy-4'-cyanobiphenyl (this work). b. 4-Hydroxybenzonitrile (Higashi & Osaki, 1977). c. 3-Hydroxybenzonitrile (Britton, 2004). d. 2-Hydroxybenzonitrile (Beswick et al., 1996). |
molecules | best r.m.s.a | pseudosym r.m.s.b |
A,B | 0.053 | 0.085 |
A,C | 0.038 | 0.068 |
A,D | 0.072 | 0.080 |
B,C | 0.034 | 0.057 |
B,D | 0.031 | 0.059 |
C,D | 0.050 | 0.057 |
a. Based on the comparison using OFIT in SHELXTL (Sheldrick, 1997). These give the best matches that can be obtained between each pair of molecules. b. Based on the pseudosymmetry elements described in the text. These elements are constrained to be parallel or perpendicular to unit-cell directions. |
Many 4,4'-disubstituted biphenyls have similar packing patterns. The dimethyl (Casalone et al., 1969), dichloro (Brock et al., 1978), and dibromo (Kronebusch et al., 1976b; Mohamed et al., 2003) compounds are isomorphous, with the molecules lined up end-to-end with X···X contacts. The bromofluoro (Gleason et al., 1991) compound is the same, with Br···F contacts. The bromocyano (Kronebusch et al., 1976a) and iodocyano (Britton & Gleason, 1991) compounds differ only in that there are X···N interactions. Otherwise the packing is the same. The unit cell for the methylcyano compound (Haase et al., 1992) suggests that this is isomorphous with the bromocyano and iodocyano compounds, but the details of the structure have not been determined. The cyanoethynyl compound (Langley et al., 1998) has a similar arrangement, with molecules forming chains with CCH···N interactions but with different side-to-side packing of the chains. In the dicyano compound (Britton & Young, 2003) the chains are tilted so that there can be antiparallel CN···NC interactions.
The structure of 4-hydroxy-4'-cyanobiphenyl has been determined to see what effect the expected OH···NC interaction has on the packing. An approximately linear molecular packing arrangement, similar to those in the 4,4'-biphenyls, seemed likely, but this would make it difficult to form the approximately linear O—H···NC interactions that appear to be favored in this type of hydrogen bond, as shown in ortho-, meta- and para-hydroxybenzonitrile [Beswick et al. (1996), Britton (2004) and Higashi & Osaki (1977), respectively].
There are four molecules in the asymmetric unit. The anisotropic displacement ellipsoids and atom labelling for molecule A are shown in Fig. 1. The ellipsoids and the labelling are similar for molecules B, C and D. The bond lengths and angles agree among the four molecules within experimental error and are all normal. As is common, the exocyclic angles at the OH-bound C atoms are unequal; the angles cis to the hydroxy H atoms average 123.0 (3)°, and those trans 117.4 (4)°. This difference is presumably due to H···H repulsion. The corresponding angles in 4,4'-biphenyldiol are 122.1 (1) and 117.8 (1)° (Jackisch et al., 1990). The torsion angles in molecules A–D are 31.8 (1), 37.0 (1), 36.4 (1) and 38.2 (1)°, respectively. The central axes of the molecules are bent. Fig. 2 shows molecule A viewed normal to the least-squares plane through atoms N14A, C13A, C1A, C4A, C7A, C10A and O15A; the next molecule in the chain [at (1 + x, y, z)] is also shown. The seven atoms are close to planar, but as can be seen from the figure, the molecule is bowed in the plane. This bowing is such that it tends to bring both the O—H···N and H···NC interactions closer to linearity. In the molecule shown, the angle between the C10A—O15A direction and the C13A—N14A direction is 8.9 (1)°. The other three molecules are similar in arrangement, with corresponding angles of 10.2 (B), 8.6 (C) and 12.2° (D).
In order to simplify the discussion of the pseudosymmetry and to make the molecular chains lie parallel to an axis, the conventional unit cell [a = 10.604 (3) Å, b = 11.826 (3) Å, c = 18.005 (5) Å, α = 103.10 (1)°, β = 100.23 (1)° and γ = 109.80 (1)°] was converted by the matrix 110/112/100 to the cell in C1 reported in the experimental data.
The packing is shown in Figs. 3 and 4, where one asymmetric unit is shown in Fig. 3 and two asymmetic units related by an inversion center at (3/4, 1/4, 1/2) are shown in Fig. 4. The four independent molecules are all aligned approximately parallel to the a axis [the deviations based on the intramolecular N···O directions are 10.2 (1), 10.4 (1), 10.1 (1) and 10.0 (1)° for molecules A, B, C and D, respectively.] The molecules form chains held together by O—H···NC hydrogen bonds. The metric data for these hydogen bonds are given in Table 1, where they are compared with similar bonds in o-, m- and p-hydroxybenzonitrile. The hydrogen bonds in the latter compounds are all almost completely linear for the O—H···NC groups, which is the ideal arrangement for such bonds. In hydroxycyanobiphenyl the bonds are not ideal; while still close to linear at O—H···N, they are bent at H···NC. This is presumably a consequence of the difficulty in forming an efficient packing with the linear arrangement. The bending does not appear to affect the O···N distances significantly.
The packing between chains involves six C—H···N contacts with H···N distances between 2.6 and 2.8 Å, and 37 C—H···C(ring) contacts with H···C distances between 2.8 and 3.1 Å. These contacts are important to the packing but none is remarkably short. This aspect of the packing in biphenyls has been discussed at length by Masunov et al. (1992).
Also evident, particularly in Fig. 4, is the pseudosymmetry relating the four crystallographically independent molecules. Such supersymmetry has been discussed extensively by Zorky and coworkers (see, among others, Zorky, 1996; Belsky et al., 1995; Zorky & Dashevskaya, 1992, 1993). Zorky & Dashevskaya (1992, 1993), in particular, describe an example of Z' = 4 that is close to that reported here.
The first hint of the pseudosymmetry can be found if we look at the coordinates of the molecular centers of the four molecules: A at (0.724, 0.127, −0.009); B at (0.606, 0.251, 1/4); C at (0.470, 0.376, 0.491); D at (0.899, 0.502, 3/4). While the x coordinates show no particular relationship, the y coordinates are at, and differ by, approximately integral multiples of b/8, and the z coordinates are at, and differ by, approximately integral multiples of c/4.
There are six kinds of pseudosymmetry elements present: (1) screw axes parallel to b, which relate A←→B and C←→D; (2) screw axes parallel to a, which relate A←→C', B←→D', C←→A', and D←→B'; (3) screw axes perpendicular to the ab plane, which relate A←→D', B←→C', C←→B', and D←→A'; (4) glide planes perpendicular to b, which relate A←→B', B←→A', C←→D', and D←→C'; (5) glide planes perpendicular to a, which relate A←→C and B←→D; (6) glide planes parallel to the ab planes, which relate A←→D and B←→C. The three glide planes, 4, 5 and 6, are related, respectively, to the three screw axes, 1, 2 and 3, by the real inversion center at (3/4, 1/4, 1/2). The pseudo-screw axes are all twofold. The details of the pseudosymmetry elements are included in the CIF in the section _geom_special_details.
It should be emphasized that the pseudosymmetry element directions are only approximately correct. The C-centered triclinic cell was chosen to make the discussion of the pseudo-symmetry simpler, but the α and γ angles differ from 90° and these differences have been ignored. For each of the pairs of molecules, the best overlap has been determined using the program OFIT in SHELXTL, and the r.m.s deviations are given in Table 2, where they are compared with the r.m.s deviations determined from the pseudosymmetry elements described above. As can be seen, the agreement is poorer, as would be expected, but still satisfactory.
The related compound 4-cyano-4'-ethynylbiphenyl (Langley et al., 1998), in which the –OH group has been replaced with –C2H, also occurs in a triclinic cell with four molecules in the asymmetric unit, and with all the molecules close to parallel to each other and forming chains with their own kind held together by C2H···NC hydrogen bonds. However, in this case, there are no significant pseudosymmetrical relationships among the molecules.
4-Chloro-2-hydroxybiphenyl (Lehmler et al., 2002), which is less closely related, also has a triclinic unit cell with four molecules in the asymmetric unit. In this case, the four independent molecules form cyclic tetrameric units rather than chains. Again, there are no significant pseudosymmetrical relationships among the molecules.
It is not clear why 4-hydroxy-4'-cyanobiphenyl should show so much pseudosymmetry while the closely related 4-cyano-4'- ethynylbiphenyl, which also has Z' = 4, shows none. Kitaigorodskii (1970) has pointed out that Z' > 1 gives more degrees of freedom and therefore can increase the packing efficiency, but this does not address the question of why some structures show pseudosymmetry and others with the same Z' do not.