The title compound, C
18H
18Cl
4N
2O
2, crystallizes as monoclinic and orthorhombic polymorphs from CHCl
3–CH
3OH solution. In both polymorphic forms, the molecule lies on a crystallographic centre of inversion (at the piperazine ring centroid) and exhibits an intramolecular O—H
N hydrogen bond. In the monoclinic polymorph (space group
P2
1/
c), the molecules are linked by intermolecular C—H
Cl hydrogen bonds into a ribbon sheet built from
R88(34) rings. In the orthorhombic polymorph (space group
Pbcn), the molecules are linked by intermolecular C—H
O hydrogen bonds into a ribbon sheet of
R66(34) rings. The sheets in the orthorhombic polymorph are crosslinked into a three-dimensional framework by π–π stacking interactions.
Supporting information
CCDC references: 661813; 661814
A mixture of 2,4-dichlorophenol (13.04 g, 80 mmol), piperazine (3.45 g, 40 mmol)
and paraformaldehyde (2.40 g, 80 mmol) in methanol (60 ml) was refluxed for 6 h. The mixture was cooled to room temperature, and the solvent evaporated
under vacuum. The product was recrystallized from CHCl3·CH3OH to give
colourless crystals suitable for X-ray analysis. Visual examination of the
crystals under a microscope showed that most of them consisted of (I), with a
small amount of (II). By crystallizing H2Cl2bpi under various conditions
we attempted to obtain extra amounts of (II); however, no remarkable
improvement was observed. Samples of the two polymorphs were isolated manually
[yield 10.40 g (59.6%); m.p. 510.0–512.1 K for (I) and 510.4–512.8 K for
(II)]. Phase transitions of one polymorph into another were not observed by
DSC. Analysis calculated for C18H18Cl4N2O2: C 49.57, H 4.16, N
6.42%; found: C 49.54, H 4.20, N 6.46%. 1H-NMR(CDCl3, p.p.m., 400 MHz):
2.66 (brs, 8H, CH2), 3.72 (s, 4H, CH2), 6.90 (d,
J = 2.4 Hz, 2H, ArH), 7.28 (d, J = 2.4 Hz, 2H, ArH), 11.2
(brs, 2H, OH).
The H atoms of the hydroxyl groups were found from a difference Fourier map. The
other H atoms were placed at idealized positions with C—H = 0.95 Å. All
the H atoms were refined as a riding model with Uiso(H) = 1.2
Ueq(C).
For both compounds, data collection: WinAFC (Rigaku/MSC, 2006); cell refinement: WinAFC; data reduction: CrystalStructure (Rigaku/MSC, 2006); program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: CrystalStructure.
(I) 4,4',6,6'-tetrachloro-2,2'-(piperazin-1,4-diyldimethylene)diphenol
top
Crystal data top
C18H18Cl4N2O2 | F(000) = 448 |
Mr = 436.14 | Dx = 1.511 Mg m−3 |
Monoclinic, P21/c | Melting point: 511 K |
Hall symbol: -P 2ybc | Mo Kα radiation, λ = 0.71069 Å |
a = 7.4861 (13) Å | Cell parameters from 25 reflections |
b = 17.2008 (13) Å | θ = 14.6–14.9° |
c = 8.0283 (19) Å | µ = 0.63 mm−1 |
β = 111.972 (13)° | T = 298 K |
V = 958.7 (3) Å3 | Prismatic, colorless |
Z = 2 | 0.25 × 0.15 × 0.15 mm |
Data collection top
Rigaku AFC7R diffractometer | θmax = 27.5° |
ω–2θ scans | h = −9→9 |
2364 measured reflections | k = 0→22 |
2215 independent reflections | l = −10→0 |
1526 reflections with F2 > 2.0σ(F2) | 3 standard reflections every 150 reflections |
Rint = 0.017 | intensity decay: 0.1% |
Refinement top
Refinement on F2 | H-atom parameters constrained |
R[F2 > 2σ(F2)] = 0.040 | w = 1/[0.0024Fo2 + 1σ(Fo2)]/(4Fo2) |
wR(F2) = 0.125 | (Δ/σ)max < 0.001 |
S = 1.01 | Δρmax = 0.68 e Å−3 |
1528 reflections | Δρmin = −0.35 e Å−3 |
127 parameters | |
Crystal data top
C18H18Cl4N2O2 | V = 958.7 (3) Å3 |
Mr = 436.14 | Z = 2 |
Monoclinic, P21/c | Mo Kα radiation |
a = 7.4861 (13) Å | µ = 0.63 mm−1 |
b = 17.2008 (13) Å | T = 298 K |
c = 8.0283 (19) Å | 0.25 × 0.15 × 0.15 mm |
β = 111.972 (13)° | |
Data collection top
Rigaku AFC7R diffractometer | Rint = 0.017 |
2364 measured reflections | 3 standard reflections every 150 reflections |
2215 independent reflections | intensity decay: 0.1% |
1526 reflections with F2 > 2.0σ(F2) | |
Refinement top
R[F2 > 2σ(F2)] = 0.040 | 127 parameters |
wR(F2) = 0.125 | H-atom parameters constrained |
S = 1.01 | Δρmax = 0.68 e Å−3 |
1528 reflections | Δρmin = −0.35 e Å−3 |
Special details top
Geometry. ENTER SPECIAL DETAILS OF THE MOLECULAR GEOMETRY |
Refinement. Refinement was performed using reflections with F2 > 2.0
σ(F2). The weighted R-factor (wR) and goodness of fit
(S) are based on F2. R-factor (gt) are based on
F. The threshold expression of F2 > 2.0 σ(F2) is
used only for calculating R-factor (gt). |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
Cl1 | −0.32583 (9) | 0.14991 (5) | 0.08772 (10) | 0.0630 (2) | |
Cl2 | 0.06831 (14) | 0.40389 (4) | 0.41664 (14) | 0.0731 (2) | |
O1 | −0.0072 (2) | 0.06476 (10) | 0.3491 (2) | 0.0507 (5) | |
N1 | 0.3760 (2) | 0.05530 (11) | 0.5370 (2) | 0.0368 (5) | |
C1 | 0.0181 (3) | 0.14211 (13) | 0.3645 (3) | 0.0389 (6) | |
C2 | −0.1247 (3) | 0.19103 (16) | 0.2520 (3) | 0.0433 (6) | |
C3 | −0.1097 (3) | 0.27050 (16) | 0.2659 (4) | 0.0504 (7) | |
C4 | 0.0514 (4) | 0.30339 (15) | 0.3944 (4) | 0.0487 (7) | |
C5 | 0.1980 (3) | 0.25661 (15) | 0.5046 (3) | 0.0447 (6) | |
C6 | 0.1833 (3) | 0.17638 (14) | 0.4917 (3) | 0.0377 (6) | |
C7 | 0.3389 (3) | 0.12623 (15) | 0.6210 (3) | 0.0449 (6) | |
C8 | 0.4707 (3) | 0.07261 (14) | 0.4110 (3) | 0.0408 (6) | |
C9 | 0.5036 (4) | −0.00153 (15) | 0.3248 (3) | 0.0419 (6) | |
H1 | 0.0971 | 0.0416 | 0.4073 | 0.057* | |
H2 | −0.2093 | 0.3026 | 0.1883 | 0.063* | |
H3 | 0.3100 | 0.2798 | 0.5902 | 0.055* | |
H4 | 0.3002 | 0.1116 | 0.7167 | 0.052* | |
H5 | 0.4546 | 0.1555 | 0.6673 | 0.052* | |
H6 | 0.3919 | 0.1070 | 0.3208 | 0.050* | |
H7 | 0.5915 | 0.0966 | 0.4744 | 0.050* | |
H8 | 0.3828 | −0.0252 | 0.2601 | 0.050* | |
H9 | 0.5666 | 0.0102 | 0.2448 | 0.050* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Cl1 | 0.0374 (3) | 0.0831 (5) | 0.0567 (4) | 0.0013 (3) | 0.0040 (2) | 0.0068 (3) |
Cl2 | 0.0903 (6) | 0.0366 (3) | 0.1081 (7) | 0.0110 (3) | 0.0552 (5) | 0.0033 (4) |
O1 | 0.0408 (9) | 0.0384 (9) | 0.0633 (12) | 0.0015 (7) | 0.0083 (8) | 0.0002 (9) |
N1 | 0.0353 (9) | 0.0354 (9) | 0.0382 (11) | 0.0084 (7) | 0.0119 (8) | 0.0029 (8) |
C1 | 0.0341 (10) | 0.0382 (12) | 0.0455 (13) | 0.0037 (9) | 0.0160 (10) | 0.0019 (10) |
C2 | 0.0328 (11) | 0.0533 (14) | 0.0444 (14) | 0.0068 (10) | 0.0152 (10) | 0.0068 (11) |
C3 | 0.0445 (13) | 0.0533 (16) | 0.0592 (18) | 0.0190 (11) | 0.0261 (13) | 0.0153 (13) |
C4 | 0.0528 (14) | 0.0360 (11) | 0.0687 (18) | 0.0085 (10) | 0.0356 (14) | 0.0046 (12) |
C5 | 0.0424 (12) | 0.0418 (12) | 0.0535 (15) | 0.0006 (11) | 0.0220 (12) | −0.0086 (12) |
C6 | 0.0358 (11) | 0.0361 (11) | 0.0418 (13) | 0.0072 (9) | 0.0154 (10) | −0.0000 (10) |
C7 | 0.0417 (12) | 0.0469 (13) | 0.0423 (14) | 0.0095 (11) | 0.0113 (11) | −0.0033 (12) |
C8 | 0.0415 (12) | 0.0368 (11) | 0.0460 (14) | 0.0064 (10) | 0.0184 (11) | 0.0080 (10) |
C9 | 0.0445 (12) | 0.0448 (12) | 0.0356 (13) | 0.0101 (10) | 0.0139 (10) | 0.0068 (10) |
Geometric parameters (Å, º) top
Cl1—C2 | 1.738 (2) | C6—C7 | 1.508 (3) |
Cl2—C4 | 1.738 (2) | C8—C9 | 1.514 (3) |
O1—C1 | 1.343 (2) | O1—H1 | 0.845 |
N1—C7 | 1.470 (3) | C3—H2 | 0.950 |
N1—C8 | 1.467 (4) | C5—H3 | 0.950 |
N1—C9i | 1.466 (3) | C7—H4 | 0.950 |
C1—C2 | 1.395 (3) | C7—H5 | 0.950 |
C1—C6 | 1.405 (2) | C8—H6 | 0.950 |
C2—C3 | 1.373 (3) | C8—H7 | 0.950 |
C3—C4 | 1.381 (3) | C9—H8 | 0.950 |
C4—C5 | 1.381 (3) | C9—H9 | 0.950 |
C5—C6 | 1.385 (3) | | |
| | | |
Cl2···O1ii | 3.419 (2) | H2···C7vii | 3.444 |
O1···Cl2iii | 3.419 (2) | H2···C8vii | 3.362 |
O1···O1iv | 3.263 (2) | H2···H5vii | 2.561 |
C2···C4v | 3.581 (5) | H2···H7vii | 2.502 |
C4···C2vi | 3.581 (5) | H2···H8ii | 3.321 |
Cl1···H3vii | 2.989 | H3···Cl1xi | 2.989 |
Cl1···H4viii | 3.302 | H3···C8vi | 3.494 |
Cl1···H5viii | 3.155 | H3···H4v | 3.510 |
Cl1···H6ix | 3.387 | H3···H6vi | 2.598 |
Cl1···H7ix | 3.507 | H4···Cl1xii | 3.302 |
Cl1···H8x | 3.419 | H4···Cl2vi | 2.784 |
Cl1···H9ix | 2.962 | H4···C4vi | 3.103 |
Cl2···H1ii | 3.391 | H4···C5vi | 3.520 |
Cl2···H4v | 2.784 | H4···H3vi | 3.510 |
Cl2···H6vi | 3.248 | H5···Cl1xii | 3.155 |
Cl2···H8ii | 3.364 | H5···C3xi | 3.309 |
Cl2···H8vi | 3.556 | H5···H2xi | 2.561 |
O1···H1iv | 2.934 | H6···Cl1xiii | 3.387 |
O1···H7ix | 3.549 | H6···Cl2v | 3.248 |
O1···H9ix | 3.124 | H6···C5v | 3.361 |
C3···H5vii | 3.309 | H6···H3v | 2.598 |
C3···H7vii | 3.433 | H7···Cl1xiii | 3.507 |
C4···H4v | 3.103 | H7···O1xiii | 3.549 |
C5···H4v | 3.520 | H7···C3xi | 3.433 |
C5···H6vi | 3.361 | H7···H2xi | 2.502 |
C7···H2xi | 3.444 | H8···Cl1x | 3.419 |
C8···H2xi | 3.362 | H8···Cl2iii | 3.364 |
C8···H3v | 3.494 | H8···Cl2v | 3.556 |
H1···Cl2iii | 3.391 | H8···H2iii | 3.321 |
H1···O1iv | 2.934 | H9···Cl1xiii | 2.962 |
H1···H1iv | 2.827 | H9···O1xiii | 3.124 |
| | | |
C7—N1—C8 | 111.78 (19) | C1—O1—H1 | 110.3 |
C7—N1—C9i | 110.15 (19) | C2—C3—H2 | 120.4 |
C8—N1—C9i | 109.3 (2) | C4—C3—H2 | 120.2 |
O1—C1—C2 | 119.36 (19) | C4—C5—H3 | 119.5 |
O1—C1—C6 | 122.56 (19) | C6—C5—H3 | 119.8 |
C2—C1—C6 | 118.1 (2) | N1—C7—H4 | 108.6 |
Cl1—C2—C1 | 118.86 (19) | N1—C7—H5 | 108.6 |
Cl1—C2—C3 | 119.24 (18) | C6—C7—H4 | 108.5 |
C1—C2—C3 | 121.9 (2) | C6—C7—H5 | 108.8 |
C2—C3—C4 | 119.4 (2) | H4—C7—H5 | 109.5 |
Cl2—C4—C3 | 119.6 (2) | N1—C8—H6 | 109.2 |
Cl2—C4—C5 | 120.26 (19) | N1—C8—H7 | 109.1 |
C3—C4—C5 | 120.2 (2) | C9—C8—H6 | 109.7 |
C4—C5—C6 | 120.7 (2) | C9—C8—H7 | 109.0 |
C1—C6—C5 | 119.8 (2) | H6—C8—H7 | 109.5 |
C1—C6—C7 | 120.2 (2) | N1i—C9—H8 | 109.5 |
C5—C6—C7 | 119.93 (19) | N1i—C9—H9 | 109.0 |
N1—C7—C6 | 112.88 (19) | C8—C9—H8 | 109.1 |
N1—C8—C9 | 110.3 (2) | C8—C9—H9 | 109.7 |
N1i—C9—C8 | 110.1 (2) | H8—C9—H9 | 109.5 |
| | | |
C2—C1—C6—C7 | 177.8 (2) | O1—C1—C6—C7 | −1.5 (4) |
C1—C6—C7—N1 | 39.8 (3) | C2—C1—C6—C5 | 1.4 (4) |
C5—C6—C7—N1 | −143.7 (2) | C6—C1—C2—Cl1 | 177.5 (2) |
C4—C5—C6—C1 | 0.4 (4) | C6—C1—C2—C3 | −1.7 (4) |
C7—N1—C8—C9 | −179.06 (17) | Cl1—C2—C3—C4 | −178.9 (2) |
C8—N1—C7—C6 | 70.4 (2) | C1—C2—C3—C4 | 0.2 (5) |
C7—N1—C9i—C8i | 178.2 (2) | C2—C3—C4—Cl2 | −178.3 (2) |
C9i—N1—C7—C6 | −167.8 (2) | C2—C3—C4—C5 | 1.6 (5) |
C8—N1—C9i—C8i | −58.6 (2) | Cl2—C4—C5—C6 | 178.0 (2) |
C9i—N1—C8—C9 | 58.7 (2) | C3—C4—C5—C6 | −1.9 (5) |
O1—C1—C2—Cl1 | −3.2 (4) | C4—C5—C6—C7 | −176.1 (3) |
O1—C1—C2—C3 | 177.7 (3) | N1—C8—C9—N1i | −59.2 (2) |
O1—C1—C6—C5 | −178.0 (2) | | |
Symmetry codes: (i) −x+1, −y, −z+1; (ii) −x, y+1/2, −z+1/2; (iii) −x, y−1/2, −z+1/2; (iv) −x, −y, −z+1; (v) x, −y+1/2, z−1/2; (vi) x, −y+1/2, z+1/2; (vii) x−1, −y+1/2, z−1/2; (viii) x−1, y, z−1; (ix) x−1, y, z; (x) −x, −y, −z; (xi) x+1, −y+1/2, z+1/2; (xii) x+1, y, z+1; (xiii) x+1, y, z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···N1 | 0.85 | 1.97 | 2.700 (2) | 145 |
C7—H4···Cl2vi | 0.95 | 2.78 | 3.688 (3) | 159 |
Symmetry code: (vi) x, −y+1/2, z+1/2. |
(II) 4,4',6,6'-tetrachloro-2,2'-(piperazin-1,4-diyldimethylene)diphenol
top
Crystal data top
C18H18Cl4N2O2 | Dx = 1.496 Mg m−3 |
Mr = 436.14 | Melting point: 512 K |
Orthorhombic, Pbcn | Mo Kα radiation, λ = 0.71069 Å |
Hall symbol: -P 2n 2ab | Cell parameters from 25 reflections |
a = 10.360 (3) Å | θ = 15.2–17.5° |
b = 12.1910 (17) Å | µ = 0.63 mm−1 |
c = 15.332 (5) Å | T = 298 K |
V = 1936.4 (9) Å3 | Block, colorless |
Z = 4 | 0.20 × 0.15 × 0.12 mm |
F(000) = 896 | |
Data collection top
Rigaku AFC7R diffractometer | θmax = 27.5° |
ω–2θ scans | h = −7→13 |
3228 measured reflections | k = −8→15 |
2222 independent reflections | l = 0→19 |
1922 reflections with F2 > 2.0σ(F2) | 3 standard reflections every 150 reflections |
Rint = 0.024 | intensity decay: 0.3% |
Refinement top
Refinement on F2 | H-atom parameters constrained |
R[F2 > 2σ(F2)] = 0.037 | w = 1/[0.0016Fo2 + 1σ(Fo2)]/(4Fo2) |
wR(F2) = 0.106 | (Δ/σ)max < 0.001 |
S = 1.00 | Δρmax = 0.46 e Å−3 |
1925 reflections | Δρmin = −0.68 e Å−3 |
127 parameters | |
Crystal data top
C18H18Cl4N2O2 | V = 1936.4 (9) Å3 |
Mr = 436.14 | Z = 4 |
Orthorhombic, Pbcn | Mo Kα radiation |
a = 10.360 (3) Å | µ = 0.63 mm−1 |
b = 12.1910 (17) Å | T = 298 K |
c = 15.332 (5) Å | 0.20 × 0.15 × 0.12 mm |
Data collection top
Rigaku AFC7R diffractometer | Rint = 0.024 |
3228 measured reflections | 3 standard reflections every 150 reflections |
2222 independent reflections | intensity decay: 0.3% |
1922 reflections with F2 > 2.0σ(F2) | |
Refinement top
R[F2 > 2σ(F2)] = 0.037 | 127 parameters |
wR(F2) = 0.106 | H-atom parameters constrained |
S = 1.00 | Δρmax = 0.46 e Å−3 |
1925 reflections | Δρmin = −0.68 e Å−3 |
Special details top
Geometry. ENTER SPECIAL DETAILS OF THE MOLECULAR GEOMETRY |
Refinement. Refinement was performed using reflections with F2 > 2.0
σ(F2). The weighted R-factor (wR) and goodness of fit
(S) are based on F2. R-factor (gt) are based on
F. The threshold expression of F2 > 2.0 σ(F2) is
used only for calculating R-factor (gt). |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
Cl1 | 0.67952 (7) | 0.32132 (7) | 0.74258 (5) | 0.0668 (2) | |
Cl2 | 1.03086 (9) | 0.60741 (6) | 0.61907 (6) | 0.0763 (3) | |
O1 | 0.85718 (16) | 0.15637 (15) | 0.67709 (13) | 0.0581 (6) | |
N1 | 1.02653 (18) | 0.08975 (15) | 0.55792 (14) | 0.0392 (6) | |
C1 | 0.8963 (2) | 0.2602 (2) | 0.65875 (17) | 0.0398 (8) | |
C2 | 0.8225 (2) | 0.3481 (2) | 0.68730 (16) | 0.0427 (8) | |
C3 | 0.8617 (2) | 0.4545 (2) | 0.67455 (18) | 0.0462 (8) | |
C4 | 0.9758 (2) | 0.4732 (2) | 0.63139 (17) | 0.0454 (8) | |
C5 | 1.0483 (2) | 0.3877 (2) | 0.59957 (18) | 0.0439 (8) | |
C6 | 1.0107 (2) | 0.2803 (2) | 0.61378 (17) | 0.0381 (7) | |
C7 | 1.0980 (2) | 0.1875 (2) | 0.58674 (19) | 0.0490 (8) | |
C8 | 0.9626 (2) | 0.10652 (19) | 0.47390 (18) | 0.0457 (8) | |
C9 | 0.8880 (2) | 0.00578 (18) | 0.44803 (17) | 0.0459 (8) | |
H1 | 0.9009 | 0.1135 | 0.6455 | 0.070* | |
H2 | 0.8110 | 0.5139 | 0.6954 | 0.055* | |
H3 | 1.1243 | 0.4029 | 0.5671 | 0.053* | |
H4 | 1.1494 | 0.1674 | 0.6355 | 0.059* | |
H5 | 1.1522 | 0.2116 | 0.5406 | 0.059* | |
H6 | 0.9074 | 0.1685 | 0.4779 | 0.055* | |
H7 | 1.0261 | 0.1192 | 0.4304 | 0.055* | |
H8 | 0.8251 | −0.0073 | 0.4919 | 0.055* | |
H9 | 0.8462 | 0.0161 | 0.3935 | 0.055* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Cl1 | 0.0493 (4) | 0.0797 (6) | 0.0714 (6) | 0.0010 (4) | 0.0136 (4) | −0.0130 (4) |
Cl2 | 0.1141 (7) | 0.0357 (4) | 0.0791 (6) | −0.0149 (4) | −0.0003 (5) | −0.0027 (3) |
O1 | 0.0633 (12) | 0.0386 (11) | 0.0725 (13) | −0.0067 (9) | 0.0244 (10) | −0.0064 (10) |
N1 | 0.0405 (12) | 0.0308 (12) | 0.0461 (14) | 0.0032 (9) | −0.0051 (10) | −0.0069 (10) |
C1 | 0.0423 (16) | 0.0341 (15) | 0.0429 (16) | −0.0047 (13) | 0.0005 (13) | −0.0043 (12) |
C2 | 0.0388 (15) | 0.0507 (17) | 0.0384 (16) | 0.0030 (14) | 0.0026 (13) | −0.0038 (14) |
C3 | 0.0551 (18) | 0.0381 (16) | 0.0454 (16) | 0.0122 (15) | −0.0098 (14) | −0.0080 (13) |
C4 | 0.0603 (19) | 0.0315 (15) | 0.0444 (18) | −0.0012 (13) | −0.0057 (14) | −0.0027 (13) |
C5 | 0.0461 (16) | 0.0408 (15) | 0.0449 (17) | −0.0103 (13) | 0.0024 (13) | −0.0046 (13) |
C6 | 0.0410 (15) | 0.0311 (13) | 0.0424 (16) | −0.0023 (12) | −0.0006 (13) | −0.0082 (11) |
C7 | 0.0446 (16) | 0.0413 (17) | 0.0612 (19) | −0.0044 (14) | 0.0034 (14) | −0.0109 (14) |
C8 | 0.0482 (16) | 0.0367 (15) | 0.0522 (18) | 0.0078 (13) | −0.0006 (14) | 0.0003 (13) |
C9 | 0.0482 (15) | 0.0395 (16) | 0.0500 (18) | 0.0128 (14) | −0.0095 (15) | −0.0041 (13) |
Geometric parameters (Å, º) top
Cl1—C2 | 1.737 (2) | C6—C7 | 1.507 (3) |
Cl2—C4 | 1.743 (2) | C8—C9 | 1.504 (3) |
O1—C1 | 1.358 (3) | O1—H1 | 0.844 |
N1—C7 | 1.470 (3) | C3—H2 | 0.950 |
N1—C8 | 1.463 (3) | C5—H3 | 0.950 |
N1—C9i | 1.466 (2) | C7—H4 | 0.950 |
C1—C2 | 1.387 (3) | C7—H5 | 0.950 |
C1—C6 | 1.393 (3) | C8—H6 | 0.950 |
C2—C3 | 1.373 (3) | C8—H7 | 0.950 |
C3—C4 | 1.374 (4) | C9—H8 | 0.950 |
C4—C5 | 1.375 (3) | C9—H9 | 0.950 |
C5—C6 | 1.383 (3) | | |
| | | |
Cl2···C5ii | 3.451 (2) | Cl2···H6ii | 3.180 |
O1···C3iii | 3.347 (3) | Cl2···H7ii | 3.470 |
C1···C1iv | 3.528 (3) | O1···H2iii | 2.480 |
C2···C5iv | 3.564 (3) | O1···H4iv | 2.880 |
C3···O1v | 3.347 (3) | C1···H4iv | 3.380 |
C3···C4iv | 3.427 (3) | C2···H4iv | 3.510 |
C4···C3iv | 3.427 (3) | C2···H7vi | 3.580 |
C5···Cl2ii | 3.451 (2) | C3···H1v | 3.370 |
C5···C2iv | 3.564 (3) | C3···H8v | 3.435 |
Cl1···H4iv | 3.190 | C4···H2iv | 3.490 |
Cl1···H7vi | 3.180 | C4···H3ii | 3.550 |
Cl1···H9vii | 3.058 | C5···H8ix | 3.510 |
Cl2···H2iv | 3.470 | C5···H9ix | 3.304 |
Cl2···H3ii | 3.280 | C8···H3vi | 3.560 |
Cl2···H4viii | 3.400 | C9···H3vi | 2.960 |
| | | |
C7—N1—C8 | 112.29 (18) | C1—O1—H1 | 107.3 |
C7—N1—C9i | 110.98 (18) | C2—C3—H2 | 121.0 |
C8—N1—C9i | 109.25 (19) | C4—C3—H2 | 121.0 |
O1—C1—C2 | 119.4 (2) | C4—C5—H3 | 119.0 |
O1—C1—C6 | 121.4 (2) | C6—C5—H3 | 120.0 |
C2—C1—C6 | 119.3 (2) | N1—C7—H4 | 108.0 |
Cl1—C2—C1 | 118.6 (2) | N1—C7—H5 | 109.0 |
Cl1—C2—C3 | 119.9 (2) | C6—C7—H4 | 108.0 |
C1—C2—C3 | 121.5 (2) | C6—C7—H5 | 109.0 |
C2—C3—C4 | 118.7 (2) | H4—C7—H5 | 110.0 |
Cl2—C4—C3 | 119.4 (2) | N1—C8—H6 | 109.0 |
Cl2—C4—C5 | 119.6 (2) | N1—C8—H7 | 109.0 |
C3—C4—C5 | 121.0 (2) | C9—C8—H6 | 111.0 |
C4—C5—C6 | 120.5 (2) | C9—C8—H7 | 108.0 |
C1—C6—C5 | 119.0 (2) | H6—C8—H7 | 109.0 |
C1—C6—C7 | 121.0 (2) | N1i—C9—H8 | 108.9 |
C5—C6—C7 | 119.9 (2) | N1i—C9—H9 | 109.0 |
N1—C7—C6 | 112.90 (19) | C8—C9—H8 | 107.7 |
N1—C8—C9 | 110.53 (19) | C8—C9—H9 | 111.0 |
N1i—C9—C8 | 110.76 (19) | H8—C9—H9 | 109.5 |
| | | |
C2—C1—C6—C7 | 176.0 (2) | C2—C1—C6—C5 | 0.6 (3) |
C1—C6—C7—N1 | 38.0 (3) | C6—C1—C2—Cl1 | 179.55 (19) |
C5—C6—C7—N1 | −146.7 (2) | C6—C1—C2—C3 | −2.0 (3) |
C4—C5—C6—C1 | 1.8 (3) | Cl1—C2—C3—C4 | 179.4 (2) |
C7—N1—C8—C9 | −178.54 (19) | C1—C2—C3—C4 | 0.9 (3) |
C8—N1—C7—C6 | 70.7 (2) | C2—C3—C4—Cl2 | −177.0 (2) |
C7—N1—C9i—C8i | 177.6 (2) | C2—C3—C4—C5 | 1.5 (4) |
C9i—N1—C7—C6 | −166.7 (2) | Cl2—C4—C5—C6 | 175.6 (2) |
C8—N1—C9i—C8i | −58.0 (2) | C3—C4—C5—C6 | −2.9 (4) |
C9i—N1—C8—C9 | 57.9 (2) | C4—C5—C6—C7 | −173.7 (2) |
O1—C1—C2—Cl1 | −2.1 (3) | O1—C1—C6—C7 | −2.3 (3) |
O1—C1—C2—C3 | 176.4 (2) | N1—C8—C9—N1i | −58.8 (2) |
O1—C1—C6—C5 | −177.7 (2) | | |
Symmetry codes: (i) −x+2, −y, −z+1; (ii) −x+2, −y+1, −z+1; (iii) −x+3/2, y−1/2, z; (iv) −x+2, y, −z+3/2; (v) −x+3/2, y+1/2, z; (vi) x−1/2, −y+1/2, −z+1; (vii) −x+3/2, −y+1/2, z+1/2; (viii) −x+5/2, y+1/2, z; (ix) x+1/2, −y+1/2, −z+1. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···N1 | 0.84 | 1.89 | 2.660 (2) | 151 |
C3—H2···O1v | 0.95 | 2.48 | 3.347 (3) | 152 |
Symmetry code: (v) −x+3/2, y+1/2, z. |
Experimental details
| (I) | (II) |
Crystal data |
Chemical formula | C18H18Cl4N2O2 | C18H18Cl4N2O2 |
Mr | 436.14 | 436.14 |
Crystal system, space group | Monoclinic, P21/c | Orthorhombic, Pbcn |
Temperature (K) | 298 | 298 |
a, b, c (Å) | 7.4861 (13), 17.2008 (13), 8.0283 (19) | 10.360 (3), 12.1910 (17), 15.332 (5) |
α, β, γ (°) | 90, 111.972 (13), 90 | 90, 90, 90 |
V (Å3) | 958.7 (3) | 1936.4 (9) |
Z | 2 | 4 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 0.63 | 0.63 |
Crystal size (mm) | 0.25 × 0.15 × 0.15 | 0.20 × 0.15 × 0.12 |
|
Data collection |
Diffractometer | Rigaku AFC7R diffractometer | Rigaku AFC7R diffractometer |
Absorption correction | – | – |
No. of measured, independent and observed [F2 > 2.0σ(F2)] reflections | 2364, 2215, 1526 | 3228, 2222, 1922 |
Rint | 0.017 | 0.024 |
(sin θ/λ)max (Å−1) | 0.650 | 0.649 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.040, 0.125, 1.01 | 0.037, 0.106, 1.00 |
No. of reflections | 1528 | 1925 |
No. of parameters | 127 | 127 |
No. of restraints | ? | ? |
H-atom treatment | H-atom parameters constrained | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.68, −0.35 | 0.46, −0.68 |
Selected torsion angles (º) for (I) topC2—C1—C6—C7 | 177.8 (2) | C5—C6—C7—N1 | −143.7 (2) |
C1—C6—C7—N1 | 39.8 (3) | C4—C5—C6—C1 | 0.4 (4) |
Hydrogen-bond geometry (Å, º) for (I) top
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···N1 | 0.845 | 1.968 | 2.700 (2) | 145 |
C7—H4···Cl2i | 0.950 | 2.784 | 3.688 (3) | 159 |
Symmetry code: (i) x, −y+1/2, z+1/2. |
Selected torsion angles (º) for (II) topC2—C1—C6—C7 | 176.0 (2) | C5—C6—C7—N1 | −146.7 (2) |
C1—C6—C7—N1 | 38.0 (3) | C4—C5—C6—C1 | 1.8 (3) |
Hydrogen-bond geometry (Å, º) for (II) top
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···N1 | 0.844 | 1.892 | 2.660 (2) | 151 |
C3—H2···O1i | 0.950 | 2.480 | 3.347 (3) | 152 |
Symmetry code: (i) −x+3/2, y+1/2, z. |
The design and synthesis of piperidine and piperazine derivatives are of interest in pharmacology (Geng et al., 2002; Favor et al., 2007). In addition, derivatives with phenol or pyridine arms can act as complexing reagents with metal ions (Chi et al., 2002; Okamatsu et al., 2007). Recently, we reported the crystal structure of a piperidine compound, 2,4-dichloro-6-(piperidin-1-ylmethyl)phenol (HClbpipe) (Kubono et al., 2005). In the supramolecular structure, intermolecular C···C and Cl···Cl contacts are observed (Kubono et al., 2005); however, in the crystal structure of the CuII complex with HClbpipe, Cu(Clbpipe)2, there are no significant intermolecular interactions, (Kubono et al., 2006). Therefore, we designed and synthesized the new supramolecular tetradentate ligand, 4,4',6,6'-tetrachloro-2,2'-(piperazin-1,4-diyldimethylene)diphenol (H2Cl2bpi), consisting of two dichlorophenol arms and a piperazine ring. This ligand H2Cl2bpi crystallizes in monoclinic, (I), and orthorhombic, (II), polymorphic forms from CHCl3·CH3OH solution. There are numerous recent studies on polymorphism in drugs (Gelbrich et al., 2007; Drebushchak et al., 2007) and supramolecular compounds (Wardell et al., 2007; Li et al., 2006). We report here the molecular and supramolecular structures of polymorphs (I) and (II).
The molecular structures of polymorphs (I) and (II) are shown in Figs. 1 and 2, respectively. In both polymorphic forms, the molecule lies on a centre of inversion at the piperazine ring centroid. The bond lengths and angles in (I) and (II) are similar, and agree with those values in the p-cresol derivative (Kuppayee et al., 1999) and 5-bromosalicylaldehyde system (Thirumurugan et al., 1998). In both (I) and (II), the piperazine rings adopt a chair conformation. The molecular structures of (I) and (II) are very similar, and thus only small differences are observed. The largest differences in bond distances and angles between the two polymorphs are less than 0.02 Å [O1—C11 1.343 (2) Å in (I), 1.358 (3) Å in (II)] and less than 2° [O1—C1—C6 122.56 (19)° in (I), 121.4 (2)° in (II)], respectively. The greatest differences are for the torsion angles involving the C6 and C7 atoms, C4—C5—C6—C7 [-176.1 (3)° (I), -173.7 (2)° in (II)] (Table 1). The differences are reflected in the orientation of the aryl rings with respect to the central piperazine rings. The dihedral angles between the mean planes of the piperazine ring and the aryl rings are slightly different in the two polymorphs, 101.28 (10)° in (I) and 104.00 (9)° in (II). The intramolecular hydrogen bond distances of O1—H1···N1 in polymorphs (I) and (II) are 2.700 (2) and 2.660 (2) Å, respectively (Tables 2 and 3).
In the crystal structure of polymorph (I), there is an intermolecular C—H···Cl hydrogen bond (Table 1). The C7 atom in the molecule at (x, y, z) acts as a hydrogen-bond donor to the Cl2 atom in the molecule at (x, 1/2 - y, 1/2 + z), forming a C(6) (Bernstein et al., 1995) chain running parallel to the [101] direction and generated by the c-glide plane at y = 0.25. A weak intermolecular C···C contact [C2···C4v 3.581 (5) Å; symmetry code: (v) x, 1/2 - y, -1/2 + z] is also observed. The molecules are linked by the C(6) chains and C···C contacts into a (100) ribbon sheet of R88(34) rings (Fig. 3). In addition, there is a weak intermolecular C—H···Cl contact [H9···Cl1vi 2.962 Å; symmetry code: (vi) 1 + x, y, z] between adjacent sheets.
In the crystal structure of polymorph (II), there is an intermolecular C—H···O hydrogen bond (Table 2). The C3 atom in the molecule at (x, y, z) acts as a hydrogen-bond donor to the O1 atom in the molecule at (3/2 - x, 1/2 + y, z), forming a C(5) chain running parallel to the [010] direction and generated by the b-glide plane at x = 0.75. The molecules are linked by the C(5) chains into a (001) ribbon sheet of R66(34) rings (Fig. 4). The sheets are crosslinked into a three-dimensional framework by π···π interactions [C1···C1vii 3.528 (3), C2···C5vii 3.564 (3) and C3···C4vii 3.427 (3) Å; symmetry code: (vii) 1 + x, y, 3/2 - z].
Each polymorph is characterized by the supramolecular interactions: for (I), C—H···Cl hydrogen bonds and weak C···C contacts, and for (II), C—H···O hydrogen bonds and π···π interactions. There are no short Cl···Cl interactions in either polymorph (I) or (II).