1,21-Henicosanediol

In the molecular structure of the title compound, C₂₁H₄₄O₂, the hydro­carbon skeleton has an all-trans conformation. One of the terminal hydroxyl groups is also trans with respect to the skeleton, while the other is gauche. In the crystal structure, the mol­ecules lie parallel to the b axis, forming layers with a thickness of b/2. The packing is similar to that in the smectic A phase of liquid crystals. These features are similar to those of the homologues with an odd number of C atoms, but different from those with an even number.

Computing details

Data collection: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1992); data reduction: TEXSAN (Molecular Structure Corporation, 1995); program(s) used to solve structure: SAPI91 (Fan, 1991); program(s) used to refine structure: TEXSAN; molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: TEXSAN.

(I)

Crystal data

C21H44O2	Dx = 1.029 Mg m^−3
Mr = 328.58	Cu Kα radiation, λ = 1.5418 Å
Orthorhombic, P212121	Cell parameters from 24 reflections
a = 7.247 (4) Å	θ = 9.2–13.9°
b = 57.940 (3) Å	µ = 0.48 mm^−1
c = 5.048 (4) Å	T = 296 K
V = 2119 (1) Å^3	Plate, colourless
Z = 4	0.50 × 0.50 × 0.05 mm
F(000) = 744

Data collection

Rigaku AFC-5R diffractometer	1583 reflections with I > 2σ(I)
Radiation source: Rigaku rotating anode	Rint = 0.022
Graphite monochromator	θmax = 70.6°, θmin = 3.1°
ω scans	h = −2→8
Absorption correction: ψ scans (North et al., 1968)	k = 0→70
Tmin = 0.825, Tmax = 0.999	l = −1→6
3723 measured reflections	3 standard reflections every 150 reflections
2355 independent reflections	intensity decay: 4%

Refinement

Refinement on F	0 restraints
Least-squares matrix: full	0 constraints
R[F^2 > 2σ(F^2)] = 0.051	H-atom parameters constrained
wR(F^2) = 0.083	w = 1/[σ^2(Fo) + 0.00106|Fo|^2]
S = 1.67	(Δ/σ)max < 0.001
1583 reflections	Δρmax = 0.11 e Å^−3
208 parameters	Δρmin = −0.22 e Å^−3

Special details

Experimental. none

Geometry. none

# O···O details from PLATON (Spek, 1998) # O1···O2ⁱ 2.778 (5) Å i = -5/2 - x,-y,1/2 + z # O2···O1ⁱⁱ 2.717 (4) Å ii= -2 - x,1/2 + y,-3/2 - z

Refinement. None

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O1	−1.0589 (4)	−0.23208 (3)	−0.6415 (4)	0.0747 (6)
O2	−1.0627 (4)	0.22760 (3)	−1.0705 (5)	0.0836 (7)
C1	−0.9982 (6)	−0.22978 (4)	−0.9085 (7)	0.083 (1)
C2	−1.0545 (6)	−0.20709 (4)	−1.0268 (6)	0.0715 (9)
C3	−0.9661 (5)	−0.18604 (4)	−0.8983 (6)	0.0595 (8)
C4	−1.0384 (5)	−0.16364 (4)	−1.0119 (6)	0.0584 (8)
C5	−0.9575 (5)	−0.14210 (4)	−0.8880 (6)	0.0549 (7)
C6	−1.0361 (5)	−0.11986 (4)	−0.9999 (6)	0.0559 (8)
C7	−0.9568 (5)	−0.09813 (4)	−0.8779 (6)	0.0553 (7)
C8	−1.0377 (5)	−0.07600 (4)	−0.9907 (6)	0.0550 (7)
C9	−0.9586 (4)	−0.05416 (4)	−0.8718 (6)	0.0537 (7)
C10	−1.0396 (5)	−0.03217 (4)	−0.9865 (6)	0.0558 (7)
C11	−0.9597 (4)	−0.01026 (4)	−0.8692 (6)	0.0546 (7)
C12	−1.0395 (4)	0.01170 (4)	−0.9854 (6)	0.0541 (7)
C13	−0.9600 (4)	0.03370 (4)	−0.8694 (6)	0.0550 (7)
C14	−1.0403 (5)	0.05562 (4)	−0.9876 (6)	0.0548 (7)
C15	−0.9608 (5)	0.07764 (4)	−0.8736 (6)	0.0555 (7)
C16	−1.0401 (5)	0.09944 (4)	−0.9947 (6)	0.0545 (7)
C17	−0.9596 (5)	0.12167 (4)	−0.8839 (6)	0.0556 (7)
C18	−1.0404 (5)	0.14326 (4)	−1.0082 (6)	0.0564 (7)
C19	−0.9612 (5)	0.16574 (4)	−0.9042 (6)	0.0574 (8)
C20	−1.0465 (5)	0.18680 (4)	−1.0349 (6)	0.0598 (8)
C21	−0.9723 (5)	0.20936 (4)	−0.9359 (6)	0.0653 (9)
H1A	−0.8715	−0.2311	−0.9209	0.0903*
H1B	−1.0560	−0.2417	−1.0173	0.0903*
H1O	−1.1937	−0.2308	−0.6318	0.0898*
H2A	−1.0255	−0.2070	−1.2098	0.0847*
H2B	−1.1875	−0.2056	−1.0095	0.0847*
H2O	−1.0137	0.2420	−1.0100	0.0948*
H3A	−0.9945	−0.1862	−0.7134	0.0679*
H3B	−0.8387	−0.1867	−0.9240	0.0679*
H4A	−1.0101	−0.1634	−1.1957	0.0701*
H4B	−1.1693	−0.1633	−0.9902	0.0701*
H5A	−0.9851	−0.1424	−0.7020	0.0648*
H5B	−0.8296	−0.1420	−0.9131	0.0648*
H6A	−1.0114	−0.1196	−1.1843	0.0675*
H6B	−1.1669	−0.1199	−0.9732	0.0675*
H7A	−0.9847	−0.0984	−0.6920	0.0650*
H7B	−0.8291	−0.0980	−0.9031	0.0650*
H8A	−1.0115	−0.0758	−1.1750	0.0648*
H8B	−1.1667	−0.0761	−0.9634	0.0648*
H9A	−0.9861	−0.0542	−0.6867	0.0631*
H9B	−0.8310	−0.0539	−0.8985	0.0631*
H10A	−1.0156	−0.0320	−1.1708	0.0658*
H10B	−1.1689	−0.0321	−0.9565	0.0658*
H11A	−0.9855	−0.0101	−0.6835	0.0644*
H11B	−0.8311	−0.0102	−0.8962	0.0644*
H12A	−1.0141	0.0117	−1.1698	0.0628*
H12B	−1.1682	0.0117	−0.9566	0.0628*
H13A	−0.9843	0.0338	−0.6832	0.0658*
H13B	−0.8302	0.0337	−0.8965	0.0658*
H14A	−1.0151	0.0555	−1.1716	0.0639*
H14B	−1.1684	0.0556	−0.9573	0.0639*
H15A	−0.9851	0.0780	−0.6874	0.0663*
H15B	−0.8304	0.0777	−0.8998	0.0663*
H16A	−1.0151	0.0991	−1.1790	0.0642*
H16B	−1.1683	0.0996	−0.9644	0.0642*
H17A	−0.9824	0.1223	−0.6969	0.0666*
H17B	−0.8287	0.1218	−0.9107	0.0666*
H18A	−1.0158	0.1426	−1.1934	0.0654*
H18B	−1.1685	0.1433	−0.9783	0.0654*
H19A	−0.9837	0.1666	−0.7168	0.0704*
H19B	−0.8309	0.1660	−0.9318	0.0704*
H20A	−1.0242	0.1857	−1.2213	0.0706*
H20B	−1.1756	0.1865	−1.0043	0.0706*
H21A	−0.8405	0.2101	−0.9723	0.0802*
H21B	−0.9891	0.2107	−0.7512	0.0802*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.110 (2)	0.0454 (8)	0.068 (1)	0.005 (1)	0.005 (2)	0.0058 (9)
O2	0.114 (2)	0.0375 (8)	0.099 (2)	−0.002 (1)	−0.026 (2)	0.0017 (9)
C1	0.138 (4)	0.042 (1)	0.070 (2)	0.002 (2)	0.012 (2)	−0.008 (1)
C2	0.113 (3)	0.046 (1)	0.056 (1)	−0.005 (2)	−0.004 (2)	−0.002 (1)
C3	0.080 (2)	0.040 (1)	0.059 (1)	−0.001 (1)	0.001 (2)	0.000 (1)
C4	0.077 (2)	0.042 (1)	0.056 (1)	0.000 (1)	−0.003 (2)	0.003 (1)
C5	0.064 (2)	0.040 (1)	0.061 (1)	−0.001 (1)	0.000 (2)	0.001 (1)
C6	0.068 (2)	0.041 (1)	0.059 (1)	0.000 (1)	−0.001 (2)	0.003 (1)
C7	0.067 (2)	0.039 (1)	0.060 (1)	−0.002 (1)	0.000 (2)	0.001 (1)
C8	0.065 (2)	0.040 (1)	0.060 (1)	0.001 (1)	−0.003 (2)	0.003 (1)
C9	0.062 (2)	0.039 (1)	0.060 (1)	−0.002 (1)	−0.002 (2)	0.002 (1)
C10	0.068 (2)	0.039 (1)	0.061 (1)	0.001 (1)	−0.002 (2)	0.002 (1)
C11	0.064 (2)	0.039 (1)	0.061 (1)	−0.002 (1)	−0.002 (2)	0.001 (1)
C12	0.064 (2)	0.038 (1)	0.060 (1)	0.001 (1)	−0.003 (2)	0.001 (1)
C13	0.065 (2)	0.040 (1)	0.061 (1)	−0.002 (1)	−0.001 (2)	0.001 (1)
C14	0.065 (2)	0.038 (1)	0.060 (1)	0.000 (1)	0.000 (2)	0.001 (1)
C15	0.066 (2)	0.039 (1)	0.061 (1)	−0.001 (1)	−0.002 (2)	−0.001 (1)
C16	0.064 (2)	0.040 (1)	0.060 (2)	0.001 (1)	−0.002 (2)	−0.002 (1)
C17	0.067 (2)	0.040 (1)	0.060 (1)	0.000 (1)	−0.003 (2)	−0.003 (1)
C18	0.069 (2)	0.039 (1)	0.061 (1)	0.003 (1)	−0.003 (2)	−0.001 (1)
C19	0.069 (2)	0.041 (1)	0.062 (2)	0.000 (1)	−0.003 (2)	−0.003 (1)
C20	0.073 (2)	0.040 (1)	0.067 (2)	0.001 (1)	−0.002 (2)	−0.001 (1)
C21	0.082 (3)	0.039 (1)	0.075 (2)	0.002 (1)	−0.001 (2)	0.000 (1)

Geometric parameters (Å, º)

O1—C1	1.424 (4)	C10—C11	1.516 (4)
O2—C21	1.417 (3)	C11—C12	1.516 (3)
C1—C2	1.501 (4)	C12—C13	1.516 (3)
C2—C3	1.523 (4)	C13—C14	1.519 (3)
C3—C4	1.513 (3)	C14—C15	1.513 (3)
C4—C5	1.514 (4)	C15—C16	1.516 (3)
C5—C6	1.518 (3)	C16—C17	1.520 (3)
C6—C7	1.515 (3)	C17—C18	1.517 (3)
C7—C8	1.521 (3)	C18—C19	1.517 (3)
C8—C9	1.513 (3)	C19—C20	1.519 (4)
C9—C10	1.518 (3)	C20—C21	1.499 (3)
O1—C1—C2	112.0 (3)	C11—C12—C13	114.2 (2)
C1—C2—C3	114.7 (3)	C12—C13—C14	113.9 (2)
C2—C3—C4	112.3 (3)	C13—C14—C15	114.2 (3)
C3—C4—C5	114.6 (3)	C14—C15—C16	113.9 (3)
C4—C5—C6	113.6 (3)	C15—C16—C17	114.3 (3)
C5—C6—C7	114.3 (3)	C16—C17—C18	113.5 (3)
C6—C7—C8	113.7 (3)	C17—C18—C19	114.8 (3)
C7—C8—C9	114.2 (3)	C18—C19—C20	112.7 (3)
C8—C9—C10	113.8 (3)	C19—C20—C21	114.2 (3)
C9—C10—C11	113.9 (2)	O2—C21—C20	108.9 (3)
C10—C11—C12	113.9 (2)
O1—C1—C2—C3	65.1 (5)	O2—C21—C20—C19	−179.6 (3)