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The crystal structures of the cyclic amines azetidine (C3H7N), pyrrolidine (C4H9N) and hexa­methyl­eneimine (homopiperidine, C6H13N), of the series (CH2)nNH, with n = 3, 4 and 6, respectively, have been determined at 170 K, following in situ crystallization from the melt. These structures provide crystallographic data to complete the homologous series of cyclic amines (CH2)nNH, for n = 2–6. Azetidine and pyrrolidine contain chains propagating along 21 screw axes, in which the mol­ecules are linked by co-operative N—H...N hydrogen bonds. Azetidine has two mol­ecules in its asymmetric unit, while pyrrolidine has only one. Hexamethyl­ene­imine contains tetra­meric hydrogen-bonded rings formed about crystallographic inversion centres, with two mol­ecules in its asymmetric unit. The observation of crystallographically distinct mol­ecules in the hydrogen-bonded chains of azetidine and cyclic hydrogen-bonded motifs in hexa­methyl­eneimine is consistent with expecta­tions derived from comparison with monoalcohols forming chains or rings by co-operative O—H...O hydrogen bonds. The next member of the cyclic amine series, hepta­methyl­eneimine, forms a cubic plastic phase on cooling from the melt.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270108026012/fa3160sup1.cif
Contains datablocks global, I, II, III

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270108026012/fa3160Isup2.hkl
Contains datablock I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270108026012/fa3160IIsup3.hkl
Contains datablock II

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270108026012/fa3160IIIsup4.hkl
Contains datablock III

CCDC references: 707206; 707207; 707208

Comment top

Contemporary developments in instrumentation and techniques for in situ crystallization have greatly simplified the task of obtaining diffraction data for low-melting materials (Boese & Nussbaumer, 1994; Davies & Bond, 2001). This manuscript describes single-crystal X-ray structures for the cyclic amines azetidine, (I), pyrrolidine, (II), and hexamethyleneimine (homopiperidine), (III), all of which are liquid under ambient conditions. Together with the previously reported structures of aziridine (Mitzel et al., 1997) and piperazine (Parkin et al., 2004), these structures provide crystallographic data to complete the homologous series of cyclic amines, (CH2)nNH, for n = 2–6.

In each structure of the series, molecules are linked by cooperative N—H···N hydrogen bonds with comparable geometric characteristics (Tables 1–3). Aziridine (n = 2), azetidine (n = 3; Fig. 1), pyrollidine (n = 4; Fig. 2) and piperazine (n = 5) all form one-dimensional hydrogen-bonded chains. In these last two structures, the chains propagate along 21 screw axes in space group P21/c, with one molecule in the asymmetric unit (Fig. 3). In azetidine, the chains also propagate along 21 screw axes in P21/c, but with two crystallographically distinct molecules in each chain (Fig. 4). Thus, every second molecule along the chain is related by the 21 screw operation, and every fourth molecule is related by translation along b. Aziridine crystallizes in space group P1 with three crystallographically distinct molecules in each hydrogen-bonded chain. The chain conformation has approximate 31 screw symmetry (Fig. 5), with every third molecule related by translation along b. In hexamethyleneimine (Fig. 6), the molecules form tetrameric rings with a closed cycle of cooperative N—H···N hydrogen bonds. The rings are formed about crystallographic inversion centres in space group P21/n, with two of the four molecules of the tetramer being crystallographically distinct (Fig. 7).

The N—H···N hydrogen-bond motifs in the cyclic amines are reminiscent of those observed frequently in monoalcohols. For example, hydrogen-bonded chains exist in both the ambient pressure (Jönsson, 1976) and high-pressure (Allan & Clark, 1999) polymorphs of ethanol, while the more bulky 3-ethyl-3-pentanol forms cyclic tetramers (Bond, 2006). The NH group resembles the OH group in that it can act simultaneously as a hydrogen-bond donor (albeit a worse one than OH; Steiner, 2002) and as an acceptor. Thus, extended chains and closed rings are expected motifs in both cases. For the monoalcohols, Brock & Duncan (1994) noted that the occurrence of structures with more than one crystallographically distinct molecule is anomalously high on account of frequent conflicts between the spatial requirements of O—H···O hydrogen bonds and the overall contraints of molecular close packing, i.e. that molecules are most often arranged about inversion centres, 21 screw axes or glide planes. Formation of extended O—H···O hydrogen-bonded chains in the monoalcohols requires that the O atoms are brought within ca 2.7–2.9 Å of each other. In the cyclic amines, the corresponding N···N distance is slightly longer (ca 3.1–3.2 Å). Within these contraints, O—H···O or N—H···N hydrogen-bonded chains might be compatible with molecular packing about 21 screw axes or glide planes, for example as in pyrrolidine and piperazine. In other cases, however, such compatibility may not be assured, and the chain motifs are therefore much more likely [compared with structures in the Cambridge Structural Database (Allen, 2002) as a whole] to be formed either with more than one crystallographically disinct molecule, as in azetidine, or around screw or roto-inversion axes of order 3, 4 or 6, as approximated by aziridine. For more bulky molecules, cyclic motifs offer a further alternative. These are commonly tetrameric and may be formed in tetragonal space groups (e.g. 2-phenyladamantan-2-ol; Singelenberg & van Eijck, 1987) or about inversion centres with two crystallographically distinct molecules, as in hexamethyleneimine and 3-ethyl-3-pentanol (Bond, 2006). It has been observed that the packing arrangements of bulky alcohols can be made to resemble those of smaller alcohols on application of increased pressure. For example, the crystal structures of 2-chlorophenol and 4-fluorophenol at ambient pressure contain hydrogen-bonded chains propagating along 32 and 3 axes, respectively, while at high pressure both contain chains along 21 axes (Oswald et al., 2005).

The crystal structure of azetidine was used as a target in the third blind test of crystal structure prediction (CSP2004) organized by the Cambridge Crystallographic Data Centre (Day et al., 2005). The two crystallographically distinct molecules provided difficulty in this exercise, and the correct structure was not present amongst the first three predictions of any of the participants. It was noted that the structure at 170 K appears to be a saddle point on the potential energy surface, with a low barrier for transformation to a postulated lower-symmetry structure in space group P1 with four molecules in the asymmetric unit.

Related literature top

For related literature, see: Allan & Clark (1999); Allen (2002); Boese & Nussbaumer (1994); Bond (2006); Brock & Duncan (1994); Bruker (2003); Davies & Bond (2001); Day et al. (2005); Görbitz (1999); Jönsson (1976); Mitzel et al. (1997); Oswald et al. (2005); Parkin et al. (2004); Singelenberg & van Eijck (1987); Steiner (2002).

Experimental top

Single crystals of pyrrolidine and hexamethyleneimine were grown in 0.3 mm diameter glass capillaries at a temperature just below the melting point of the sample, using the manual zone-refinement technique described by Davies & Bond (2001). The diffraction patterns were indexed at a temperature just below the melting point from a series of images collected by rotation about the capillary axis, with the capillary remaining in the horizontal position in which the crystal was grown. Moving the capillary away from horizontal at this delicate stage resulted in loss of the crystal, while subsequent cooling (to 170 K) for data collection caused growth of multiple crystals. The orientation matrix established for the initial single crystal was retained and used throughout the data collection and integration, and any possible overlap with diffraction patterns from other crystal components was ignored. For both compounds, this strategy provided acceptable Rint values, although the relatively high R values for refinement of hexamethyleneimine are likely to be attributable largely to more significant overlap in its diffraction pattern. Since there were clearly contributions from many crystals, however, the approximations associated with ignoring overlap completely were preferred to the approximations associated with integration on the basis of numerous partially overlapping components. It was not possible to grow suitable crystals of azetidine using the manual technique and crystallization was therefore achieved from a sample mounted in a 0.66 mm diameter capillary held at 170 K, using the laser-assisted zone-refinement technique of Boese & Nussbaumer (1994). Again, the diffraction pattern contained contributions from more than one crystal, but a single crystal could be indexed using the program GEMINI (Bruker, 2003) and integration on the basis of this single component provided good results. In all cases, the exact size of the crystal used for data collection is uncertain, and it is probable that the length along the capillary axis exceeds the size of the X-ray beam. This seems to have little influence on the final refined parameters (Görbitz, 1999). Following data collection at 170 K, further cooling of the crystals caused deterioration of the peak shapes for all three compounds, to the extent that no further useful data could be obtained. Attempts were made to crystallize the next member of the series, heptamethyleneimine, but this forms a plastic phase on cooling from the melt. The diffraction pattern could be indexed on the basis of a cubic lattice with dimension 11.647 (3) Å, but it was not possible to establish any definite structural model.

Refinement top

H atoms bound to C atoms were positioned geometrically and allowed to ride during refinement, with C—H = 0.99 Å and Uiso(H) = 1.2Ueq(C). H atoms of the NH groups were located in difference Fourier maps and refined with isotropic displacement parameters. For azetidine and pyrrolidine, no restraints were required. For hexamethyleneimine, the two N—H distances were restrained to a common refined value with standard uncertainty 0.01 Å. Atoms C4, C5, C11 and C12 in hexamethyleneimine were modelled as disordered, each as two components with site occupancy factor 0.5. The C—C bonds in this region (12 in total) were restrained to a common refined value with standard uncertainty 0.01 Å.

Computing details top

Data collection: SMART (Bruker, 1997) for (I); APEX2 (Bruker, 2004) for (II), (III). For all compounds, cell refinement: SAINT (Bruker, 2003); data reduction: SAINT (Bruker, 2003). Program(s) used to solve structure: SIR92 (Altomare et al., 1994) for (I); SHELXTL (Sheldrick, 2008) for (II), (III). For all compounds, program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008) and Mercury (Macrae et al., 2006); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The two molecules in the asymmetric unit of azetidine, (I), with displacement ellipsoids drawn at the 50% probability level, except for H atoms bound to C atoms, which are shown as small spheres of arbitrary radii.
[Figure 2] Fig. 2. The molecular structure of pyrrolidine, (II), with displacement ellipsoids drawn at the 50% probability level, except for H atoms bound to C atoms,which are shown as small spheres of arbitrary radii.
[Figure 3] Fig. 3. A view of pyrrolidine along the c axis, showing two chains linked by cooperative N—H···N hydrogen bonds (dashed lines) propagating along 21 screw axes parallel to the baxis . H atoms bound to C atoms have been omitted. [Symmetry code: (i) -x, -1/2 + y, 1/2 - z.]
[Figure 4] Fig. 4. A view of azetidine along the c axis, showing one chain linked by cooperative N—H···N hydrogen bonds (dashed lines) propagating along a 21 screw axis parallel to the b axis. The two crystallographically distinct molecules and their symmetry equivalents are distinguished by their shading. H atoms bound to C atoms have been omitted. [Symmetry codes: (i) 1 - x, -1/2 + y, 1/2 - z; (ii) 1 - x, 1/2 + y, 1/2 - z.]
[Figure 5] Fig. 5. Perpendicular views of the hydrogen-bonded chains in aziridine (Mitzel et al., 1997), showing the approximate 31 screw symmetry. The three crystallographically distinct molecules and their symmetry equivalents are distinguished by their shading. H atoms bound to C atoms have been omitted.
[Figure 6] Fig. 6. The two molecules in the asymmetric unit of hexamethyleneimine, (III), with displacement ellipsoids drawn at the 50% probability level, except for H atoms bound to C atoms, which are shown as small spheres of arbitrary radii.
[Figure 7] Fig. 7. The unit-cell contents of hexamethyleneimine, showing tetramers linked by cooperative N—H···N hydrogen bonds (dashed lines). The two crystallographically distinct molecules and their symmetry equivalents are distinguished by their shading. H atoms bound to C atoms have been omitted.
(I) azetidine top
Crystal data top
C3H7NF(000) = 256
Mr = 57.10Dx = 1.007 Mg m3
Monoclinic, P21/cMelting point: 190 K
Hall symbol: -P 2ybcMo Kα radiation, λ = 0.71073 Å
a = 9.507 (3) ÅCell parameters from 1395 reflections
b = 9.122 (3) Åθ = 2–25°
c = 9.790 (3) ŵ = 0.06 mm1
β = 117.469 (4)°T = 170 K
V = 753.3 (4) Å3Cylinder, colourless
Z = 81.00 × 0.33 (radius) mm
Data collection top
Bruker SMART APEX CCD area-detector
diffractometer
1782 independent reflections
Radiation source: fine-focus sealed tube1144 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.035
ϕ and ω scansθmax = 28.3°, θmin = 2.4°
Absorption correction: multi-scan
(SADABS; Bruker, 2003)
h = 1012
Tmin = 0.688, Tmax = 0.960k = 1112
4439 measured reflectionsl = 1212
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.056H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.162 w = 1/[σ2(Fo2) + (0.067P)2 + 0.1013P]
where P = (Fo2 + 2Fc2)/3
S = 1.04(Δ/σ)max < 0.001
1782 reflectionsΔρmax = 0.18 e Å3
83 parametersΔρmin = 0.18 e Å3
0 restraintsExtinction correction: SHELXTL (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.044 (9)
Crystal data top
C3H7NV = 753.3 (4) Å3
Mr = 57.10Z = 8
Monoclinic, P21/cMo Kα radiation
a = 9.507 (3) ŵ = 0.06 mm1
b = 9.122 (3) ÅT = 170 K
c = 9.790 (3) Å1.00 × 0.33 (radius) mm
β = 117.469 (4)°
Data collection top
Bruker SMART APEX CCD area-detector
diffractometer
1782 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2003)
1144 reflections with I > 2σ(I)
Tmin = 0.688, Tmax = 0.960Rint = 0.035
4439 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0560 restraints
wR(F2) = 0.162H atoms treated by a mixture of independent and constrained refinement
S = 1.04Δρmax = 0.18 e Å3
1782 reflectionsΔρmin = 0.18 e Å3
83 parameters
Special details top

Experimental. Crystal grown in situ at 170 K using the laser-assisted zone-refinment technique of Boese (Boese & Nussbaumer, 1994).

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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
N10.33607 (17)0.80512 (15)0.10290 (15)0.0489 (4)
H10.412 (2)0.851 (2)0.178 (2)0.058 (5)*
C20.3048 (2)0.8502 (2)0.05269 (18)0.0568 (5)
H2A0.33600.77610.10750.068*
H2B0.34840.94780.05650.068*
C30.1294 (2)0.8517 (3)0.1004 (2)0.0685 (6)
H3A0.07260.76130.15320.082*
H3B0.07330.94060.15740.082*
C40.1775 (2)0.8558 (2)0.07009 (19)0.0642 (5)
H4A0.17610.95540.10960.077*
H4B0.11850.78580.10180.077*
N50.37687 (16)0.46573 (16)0.13886 (14)0.0490 (4)
H50.368 (2)0.559 (2)0.1393 (19)0.058 (5)*
C60.3319 (2)0.4012 (2)0.01410 (19)0.0609 (5)
H6A0.42330.36990.02950.073*
H6B0.25760.46240.10100.073*
C70.2523 (2)0.2769 (2)0.0269 (2)0.0645 (5)
H7A0.32010.18940.07060.077*
H7B0.14640.24980.05600.077*
C80.2492 (2)0.3812 (2)0.1461 (2)0.0630 (5)
H8A0.14850.43610.11020.076*
H8B0.27980.33520.24750.076*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0523 (8)0.0475 (8)0.0399 (7)0.0018 (6)0.0153 (6)0.0022 (6)
C20.0585 (11)0.0710 (12)0.0423 (9)0.0021 (8)0.0246 (8)0.0016 (8)
C30.0559 (11)0.0975 (15)0.0452 (10)0.0039 (10)0.0174 (8)0.0017 (9)
C40.0572 (11)0.0907 (15)0.0483 (10)0.0012 (9)0.0276 (8)0.0050 (9)
N50.0570 (8)0.0415 (8)0.0417 (7)0.0025 (6)0.0171 (6)0.0009 (5)
C60.0651 (11)0.0696 (13)0.0527 (10)0.0087 (9)0.0312 (8)0.0084 (8)
C70.0629 (12)0.0650 (12)0.0625 (11)0.0167 (9)0.0262 (9)0.0164 (9)
C80.0774 (13)0.0644 (12)0.0561 (10)0.0119 (9)0.0384 (9)0.0041 (8)
Geometric parameters (Å, º) top
N1—C41.464 (2)N5—C81.467 (2)
N1—C21.470 (2)N5—C61.477 (2)
N1—H10.87 (2)N5—H50.86 (2)
C2—C31.510 (3)C6—C71.516 (3)
C2—H2A0.99C6—H6A0.99
C2—H2B0.99C6—H6B0.99
C3—C41.513 (2)C7—C81.517 (2)
C3—H3A0.99C7—H7A0.99
C3—H3B0.99C7—H7B0.99
C4—H4A0.99C8—H8A0.99
C4—H4B0.99C8—H8B0.99
C4—N1—C289.34 (12)C8—N5—C688.87 (12)
C4—N1—H1114.0 (12)C8—N5—H5115.9 (12)
C2—N1—H1116.1 (12)C6—N5—H5114.7 (11)
N1—C2—C389.39 (12)N5—C6—C788.64 (13)
N1—C2—H2A113.7N5—C6—H6A113.9
C3—C2—H2A113.7C7—C6—H6A113.9
N1—C2—H2B113.7N5—C6—H6B113.9
C3—C2—H2B113.7C7—C6—H6B113.9
H2A—C2—H2B111.0H6A—C6—H6B111.1
C2—C3—C485.99 (13)C6—C7—C885.61 (14)
C2—C3—H3A114.3C6—C7—H7A114.4
C4—C3—H3A114.3C8—C7—H7A114.4
C2—C3—H3B114.3C6—C7—H7B114.4
C4—C3—H3B114.3C8—C7—H7B114.4
H3A—C3—H3B111.5H7A—C7—H7B111.5
N1—C4—C389.50 (13)N5—C8—C788.98 (12)
N1—C4—H4A113.7N5—C8—H8A113.8
C3—C4—H4A113.7C7—C8—H8A113.8
N1—C4—H4B113.7N5—C8—H8B113.8
C3—C4—H4B113.7C7—C8—H8B113.8
H4A—C4—H4B111.0H8A—C8—H8B111.0
C4—N1—C2—C318.32 (15)C8—N5—C6—C721.33 (15)
N1—C2—C3—C417.74 (15)N5—C6—C7—C820.66 (14)
C2—N1—C4—C318.28 (15)C6—N5—C8—C721.33 (15)
C2—C3—C4—N117.81 (15)C6—C7—C8—N520.80 (14)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N5—H5···N10.86 (2)2.27 (2)3.120 (2)171.5 (15)
N1—H1···N5i0.87 (2)2.24 (2)3.102 (2)174.4 (16)
Symmetry code: (i) x+1, y+1/2, z+1/2.
(II) pyrrolidine top
Crystal data top
C4H9NF(000) = 160
Mr = 71.12Dx = 1.042 Mg m3
Monoclinic, P21/cMelting point: 210 K
Hall symbol: -P 2ybcMo Kα radiation, λ = 0.71073 Å
a = 8.6753 (8) ÅCell parameters from 2626 reflections
b = 5.2078 (5) Åθ = 2.5–26.1°
c = 10.7108 (10) ŵ = 0.06 mm1
β = 110.451 (3)°T = 170 K
V = 453.41 (7) Å3Cylinder, colourless
Z = 40.35 × 0.15 (radius) mm
Data collection top
Bruker Nonius X8 APEXII CCD area-detector
diffractometer
900 independent reflections
Radiation source: fine-focus sealed tube760 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.026
thin–slice ω and ϕ scansθmax = 26.1°, θmin = 4.0°
Absorption correction: multi-scan
(SADABS; Bruker, 2003)
h = 1010
Tmin = 0.853, Tmax = 0.977k = 66
5429 measured reflectionsl = 1313
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)] = 0.042Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.110H atoms treated by a mixture of independent and constrained refinement
S = 1.06 w = 1/[σ2(Fo2) + (0.0456P)2 + 0.1266P]
where P = (Fo2 + 2Fc2)/3
900 reflections(Δ/σ)max < 0.001
50 parametersΔρmax = 0.16 e Å3
0 restraintsΔρmin = 0.13 e Å3
Crystal data top
C4H9NV = 453.41 (7) Å3
Mr = 71.12Z = 4
Monoclinic, P21/cMo Kα radiation
a = 8.6753 (8) ŵ = 0.06 mm1
b = 5.2078 (5) ÅT = 170 K
c = 10.7108 (10) Å0.35 × 0.15 (radius) mm
β = 110.451 (3)°
Data collection top
Bruker Nonius X8 APEXII CCD area-detector
diffractometer
900 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2003)
760 reflections with I > 2σ(I)
Tmin = 0.853, Tmax = 0.977Rint = 0.026
5429 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0420 restraints
wR(F2) = 0.110H atoms treated by a mixture of independent and constrained refinement
S = 1.06Δρmax = 0.16 e Å3
900 reflectionsΔρmin = 0.13 e Å3
50 parameters
Special details top

Experimental. Xtal grown in situ at ca 203 K in 0.3 mm capillary. The crystal length was not estimated, but it probably exceeded the width of the collimator. There were certainly several crystals present at 170 K. One crystal could be indexed very close to the melting point then only this one was considered at the lower temperature. Indexing at 170 K was not possible.

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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
N10.10684 (13)0.5232 (2)0.30411 (12)0.0402 (3)
H10.038 (2)0.411 (3)0.2626 (17)0.054 (5)*
C20.18779 (17)0.4308 (3)0.43977 (13)0.0422 (4)
H2A0.10610.35510.47450.051*
H2B0.24410.57410.49890.051*
C30.31260 (16)0.2278 (3)0.43463 (13)0.0423 (4)
H3A0.41450.24000.51380.051*
H3B0.26630.05290.43050.051*
C40.34677 (18)0.2893 (3)0.30783 (15)0.0463 (4)
H4A0.31770.14190.24550.056*
H4B0.46430.33180.32840.056*
C50.23822 (19)0.5199 (3)0.24830 (14)0.0465 (4)
H5A0.30320.68040.27130.056*
H5B0.19140.50480.15000.056*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0346 (6)0.0328 (6)0.0469 (7)0.0027 (5)0.0062 (5)0.0002 (5)
C20.0442 (8)0.0433 (8)0.0425 (8)0.0096 (6)0.0192 (6)0.0010 (6)
C30.0429 (7)0.0417 (8)0.0406 (7)0.0109 (6)0.0124 (6)0.0015 (6)
C40.0483 (8)0.0421 (8)0.0554 (9)0.0047 (6)0.0269 (7)0.0024 (6)
C50.0644 (9)0.0331 (7)0.0477 (8)0.0005 (6)0.0270 (7)0.0012 (6)
Geometric parameters (Å, º) top
N1—C21.4570 (17)C3—H3A0.99
N1—C51.4604 (18)C3—H3B0.99
N1—H10.84 (2)C4—C51.522 (2)
C2—C31.5281 (17)C4—H4A0.99
C2—H2A0.99C4—H4B0.99
C2—H2B0.99C5—H5A0.99
C3—C41.5220 (19)C5—H5B0.99
C2—N1—C5103.38 (10)H3A—C3—H3B108.9
C2—N1—H1107.6 (12)C3—C4—C5104.77 (11)
C5—N1—H1106.5 (11)C3—C4—H4A110.8
N1—C2—C3107.05 (10)C5—C4—H4A110.8
N1—C2—H2A110.3C3—C4—H4B110.8
C3—C2—H2A110.3C5—C4—H4B110.8
N1—C2—H2B110.3H4A—C4—H4B108.9
C3—C2—H2B110.3N1—C5—C4107.14 (11)
H2A—C2—H2B108.6N1—C5—H5A110.3
C4—C3—C2104.36 (11)C4—C5—H5A110.3
C4—C3—H3A110.9N1—C5—H5B110.3
C2—C3—H3A110.9C4—C5—H5B110.3
C4—C3—H3B110.9H5A—C5—H5B108.5
C2—C3—H3B110.9
C5—N1—C2—C335.77 (14)C2—N1—C5—C435.32 (14)
N1—C2—C3—C422.47 (15)C3—C4—C5—N121.25 (15)
C2—C3—C4—C50.69 (15)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1···N1i0.84 (2)2.35 (2)3.1716 (13)163.7 (15)
Symmetry code: (i) x, y1/2, z+1/2.
(III) hexamethyleneimine top
Crystal data top
C6H13NF(000) = 448
Mr = 99.17Dx = 0.998 Mg m3
Monoclinic, P21/nMelting point: 236 K
Hall symbol: -P 2ynMo Kα radiation, λ = 0.71073 Å
a = 11.0201 (14) ÅCell parameters from 6154 reflections
b = 10.3027 (13) Åθ = 2.6–23.2°
c = 12.7322 (15) ŵ = 0.06 mm1
β = 114.110 (5)°T = 170 K
V = 1319.5 (3) Å3Cylinder, colourless
Z = 80.35 × 0.15 (radius) mm
Data collection top
Bruker Nonius X8 APEXII CCD area-detector
diffractometer
2509 independent reflections
Radiation source: fine-focus sealed tube1824 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.051
thin–slice ω and ϕ scansθmax = 25.9°, θmin = 3.7°
Absorption correction: multi-scan
(SADABS; Bruker, 2003)
h = 1213
Tmin = 0.688, Tmax = 0.981k = 1212
16092 measured reflectionsl = 1415
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)] = 0.083Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.269H atoms treated by a mixture of independent and constrained refinement
S = 1.12 w = 1/[σ2(Fo2) + (0.1254P)2 + 0.8949P]
where P = (Fo2 + 2Fc2)/3
2509 reflections(Δ/σ)max < 0.001
173 parametersΔρmax = 0.29 e Å3
14 restraintsΔρmin = 0.22 e Å3
Crystal data top
C6H13NV = 1319.5 (3) Å3
Mr = 99.17Z = 8
Monoclinic, P21/nMo Kα radiation
a = 11.0201 (14) ŵ = 0.06 mm1
b = 10.3027 (13) ÅT = 170 K
c = 12.7322 (15) Å0.35 × 0.15 (radius) mm
β = 114.110 (5)°
Data collection top
Bruker Nonius X8 APEXII CCD area-detector
diffractometer
2509 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2003)
1824 reflections with I > 2σ(I)
Tmin = 0.688, Tmax = 0.981Rint = 0.051
16092 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.08314 restraints
wR(F2) = 0.269H atoms treated by a mixture of independent and constrained refinement
S = 1.12Δρmax = 0.29 e Å3
2509 reflectionsΔρmin = 0.22 e Å3
173 parameters
Special details top

Experimental. Xtal grown in situ in 0.3 mm capillary at ca 230 K. The crystal length was not estimated, but it probably exceeded the width of the collimator. There were certainly several crystals present at 170 K. One crystal could be indexed very close to the melting point then only this one was considered at the lower temperature. The multi-scan correction is accounting for effects other than absoprtion by the crystal, including absoption by the capillary and the probable presence of overlapping reflections from other crystals present.

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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*/UeqOcc. (<1)
N10.3562 (2)0.5819 (2)0.0683 (2)0.0424 (6)
H10.350 (3)0.515 (3)0.021 (2)0.042 (7)*
C20.3410 (3)0.5335 (3)0.1691 (3)0.0523 (8)
H2A0.37810.44470.18580.063*
H2B0.24500.52770.15160.063*
C30.4084 (3)0.6168 (3)0.2764 (3)0.0608 (9)
H3A0.35790.60700.32480.073*0.50
H3B0.49840.58110.32050.073*0.50
H3C0.39870.57430.34230.073*0.50
H3D0.50450.62320.29440.073*0.50
C40.4224 (6)0.7613 (6)0.2587 (5)0.0504 (17)0.50
H4A0.49610.77370.23430.060*0.50
H4B0.44720.80610.33340.060*0.50
C50.2980 (6)0.8258 (7)0.1704 (5)0.0523 (18)0.50
H5A0.21870.78620.17540.063*0.50
H5B0.29900.91900.18970.063*0.50
C60.2860 (4)0.8138 (3)0.0489 (3)0.0644 (9)
H6A0.37030.84160.04560.077*0.50
H6B0.21450.87200.00160.077*0.50
H6C0.33060.85660.00470.077*0.50
H6D0.20020.85890.02930.077*0.50
C4A0.3495 (9)0.7523 (6)0.2608 (6)0.0672 (19)0.50
H4C0.25280.74390.23900.081*0.50
H4D0.38800.79700.33620.081*0.50
C5A0.3693 (10)0.8377 (7)0.1738 (6)0.069 (2)0.50
H5C0.35420.92850.19090.082*0.50
H5D0.46370.83080.18590.082*0.50
C70.2550 (3)0.6757 (3)0.0052 (3)0.0602 (9)
H7A0.17020.64910.00830.072*
H7B0.24180.67380.07650.072*
N80.6496 (2)0.6463 (2)0.09841 (19)0.0433 (6)
H80.567 (3)0.630 (3)0.093 (3)0.065 (10)*
C90.7372 (3)0.6199 (4)0.2172 (3)0.0678 (10)
H9A0.70170.54460.24400.081*
H9B0.73580.69560.26450.081*
C100.8784 (3)0.5921 (4)0.2377 (3)0.0741 (11)
H10A0.88960.49660.24060.089*0.50
H10B0.93570.62580.31500.089*0.50
H10C0.92840.56850.31960.089*0.50
H10D0.88030.51620.19060.089*0.50
C110.9331 (8)0.6453 (9)0.1524 (10)0.084 (3)0.50
H11A1.03120.63830.19100.101*0.50
H11B0.90400.58440.08660.101*0.50
C120.9033 (8)0.7784 (9)0.1027 (9)0.080 (3)0.50
H12A0.92310.84140.16630.095*0.50
H12B0.96360.79780.06460.095*0.50
C130.7655 (4)0.7984 (4)0.0191 (4)0.0742 (11)
H13A0.74780.73880.04650.089*0.50
H13B0.75740.88820.01090.089*0.50
H13C0.78920.89170.02650.089*0.50
H13D0.72770.77670.06390.089*0.50
C11A0.9460 (7)0.7015 (8)0.2099 (6)0.064 (2)0.50
H11C1.04300.68520.24250.076*0.50
H11D0.93030.78200.24500.076*0.50
C12A0.8942 (7)0.7187 (10)0.0800 (6)0.063 (2)0.50
H12C0.87920.63120.04470.075*0.50
H12D0.96530.76020.06320.075*0.50
C140.6593 (4)0.7779 (3)0.0635 (4)0.0691 (10)
H14A0.67750.83610.13010.083*
H14B0.57240.80340.00270.083*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0375 (12)0.0423 (12)0.0466 (13)0.0031 (9)0.0162 (10)0.0095 (10)
C20.0548 (17)0.0472 (16)0.0523 (17)0.0039 (13)0.0193 (13)0.0000 (13)
C30.0609 (19)0.072 (2)0.0455 (17)0.0014 (16)0.0176 (14)0.0017 (15)
C40.035 (3)0.065 (4)0.051 (4)0.015 (3)0.017 (3)0.029 (3)
C50.037 (3)0.045 (4)0.076 (5)0.008 (3)0.024 (3)0.024 (3)
C60.068 (2)0.0451 (17)0.070 (2)0.0068 (14)0.0182 (17)0.0013 (15)
C4A0.065 (5)0.079 (5)0.057 (4)0.008 (4)0.024 (4)0.027 (4)
C5A0.085 (6)0.043 (4)0.081 (6)0.018 (4)0.038 (5)0.019 (3)
C70.0635 (19)0.0502 (18)0.0505 (18)0.0010 (14)0.0064 (15)0.0010 (13)
N80.0340 (12)0.0463 (13)0.0486 (13)0.0034 (9)0.0158 (10)0.0062 (10)
C90.0589 (19)0.093 (3)0.0486 (18)0.0053 (18)0.0188 (15)0.0027 (17)
C100.0470 (18)0.092 (3)0.063 (2)0.0029 (17)0.0019 (16)0.0085 (19)
C110.038 (4)0.085 (6)0.124 (9)0.006 (4)0.029 (5)0.007 (6)
C120.057 (5)0.085 (7)0.092 (7)0.048 (5)0.026 (5)0.024 (5)
C130.077 (2)0.058 (2)0.095 (3)0.0026 (17)0.043 (2)0.0181 (18)
C11A0.035 (3)0.072 (5)0.062 (4)0.017 (3)0.003 (3)0.014 (4)
C12A0.035 (4)0.088 (7)0.062 (5)0.028 (4)0.017 (3)0.003 (5)
C140.063 (2)0.0527 (18)0.094 (3)0.0112 (16)0.0354 (19)0.0114 (18)
Geometric parameters (Å, º) top
N1—C71.446 (4)N8—C141.444 (4)
N1—C21.449 (4)N8—C91.449 (4)
N1—H10.90 (2)N8—H80.90 (3)
C2—C31.524 (4)C9—C101.498 (5)
C2—H2A0.99C9—H9A0.99
C2—H2B0.99C9—H9B0.99
C3—C41.523 (6)C10—C111.542 (8)
C3—H3A0.99C10—H10A0.99
C3—H3B0.99C10—H10B0.99
C4—C51.525 (7)C11—C121.490 (8)
C4—H4A0.99C11—H11A0.99
C4—H4B0.99C11—H11B0.99
C5—C61.503 (7)C12—C131.470 (8)
C5—H5A0.99C12—H12A0.99
C5—H5B0.99C12—H12B0.99
C6—C71.515 (4)C13—C141.509 (5)
C6—H6A0.99C13—H13A0.99
C6—H6B0.99C13—H13B0.99
C4A—C5A1.498 (8)C11A—C12A1.524 (8)
C4A—H4C0.99C11A—H11C0.99
C4A—H4D0.99C11A—H11D0.99
C5A—H5C0.99C12A—H12C0.99
C5A—H5D0.99C12A—H12D0.99
C7—H7A0.99C14—H14A0.99
C7—H7B0.99C14—H14B0.99
C7—N1—C2112.3 (2)C14—N8—C9113.3 (3)
C7—N1—H1107.9 (18)C14—N8—H8110 (2)
C2—N1—H1109.0 (18)C9—N8—H8106 (2)
N1—C2—C3114.2 (2)N8—C9—C10114.8 (3)
N1—C2—H2A108.7N8—C9—H9A108.6
C3—C2—H2A108.7C10—C9—H9A108.6
N1—C2—H2B108.7N8—C9—H9B108.6
C3—C2—H2B108.7C10—C9—H9B108.6
H2A—C2—H2B107.6H9A—C9—H9B107.5
C4—C3—C2117.4 (3)C9—C10—C11119.1 (4)
C4—C3—H3A108.0C9—C10—H10A107.5
C2—C3—H3A108.0C11—C10—H10A107.5
C4—C3—H3B108.0C9—C10—H10B107.5
C2—C3—H3B108.0C11—C10—H10B107.5
H3A—C3—H3B107.2H10A—C10—H10B107.0
C3—C4—C5114.8 (5)C12—C11—C10123.0 (8)
C3—C4—H4A108.6C12—C11—H11A106.6
C5—C4—H4A108.6C10—C11—H11A106.6
C3—C4—H4B108.6C12—C11—H11B106.6
C5—C4—H4B108.6C10—C11—H11B106.6
H4A—C4—H4B107.5H11A—C11—H11B106.5
C6—C5—C4113.4 (5)C13—C12—C11114.8 (6)
C6—C5—H5A108.9C13—C12—H12A108.6
C4—C5—H5A108.9C11—C12—H12A108.6
C6—C5—H5B108.9C13—C12—H12B108.6
C4—C5—H5B108.9C11—C12—H12B108.6
H5A—C5—H5B107.7H12A—C12—H12B107.5
C5—C6—C7111.6 (4)C12—C13—C14116.0 (6)
C5—C6—H6A109.3C12—C13—H13A108.3
C7—C6—H6A109.3C14—C13—H13A108.3
C5—C6—H6B109.3C12—C13—H13B108.3
C7—C6—H6B109.3C14—C13—H13B108.3
H6A—C6—H6B108.0H13A—C13—H13B107.4
C5A—C4A—H4C108.1C12A—C11A—H11C109.6
C5A—C4A—H4D108.1C12A—C11A—H11D109.6
H4C—C4A—H4D107.3H11C—C11A—H11D108.1
C4A—C5A—H5C107.7C11A—C12A—H12C107.9
C4A—C5A—H5D107.7C11A—C12A—H12D107.9
H5C—C5A—H5D107.1H12C—C12A—H12D107.2
N1—C7—C6114.6 (3)N8—C14—C13114.4 (3)
N1—C7—H7A108.6N8—C14—H14A108.7
C6—C7—H7A108.6C13—C14—H14A108.7
N1—C7—H7B108.6N8—C14—H14B108.7
C6—C7—H7B108.6C13—C14—H14B108.7
H7A—C7—H7B107.6H14A—C14—H14B107.6
C7—N1—C2—C386.5 (3)C14—N8—C9—C1080.7 (4)
N1—C2—C3—C428.7 (5)N8—C9—C10—C1124.7 (7)
C2—C3—C4—C544.9 (6)C9—C10—C11—C1241.5 (11)
C3—C4—C5—C685.3 (7)C10—C11—C12—C1370.5 (14)
C4—C5—C6—C770.5 (6)C11—C12—C13—C1460.4 (11)
C2—N1—C7—C685.2 (3)C9—N8—C14—C1387.7 (4)
C5—C6—C7—N162.3 (4)C12—C13—C14—N864.6 (6)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N8—H8···N10.90 (3)2.27 (3)3.167 (3)176 (3)
N1—H1···N8i0.90 (2)2.25 (3)3.150 (3)175 (2)
Symmetry code: (i) x+1, y+1, z.

Experimental details

(I)(II)(III)
Crystal data
Chemical formulaC3H7NC4H9NC6H13N
Mr57.1071.1299.17
Crystal system, space groupMonoclinic, P21/cMonoclinic, P21/cMonoclinic, P21/n
Temperature (K)170170170
a, b, c (Å)9.507 (3), 9.122 (3), 9.790 (3)8.6753 (8), 5.2078 (5), 10.7108 (10)11.0201 (14), 10.3027 (13), 12.7322 (15)
β (°) 117.469 (4) 110.451 (3) 114.110 (5)
V3)753.3 (4)453.41 (7)1319.5 (3)
Z848
Radiation typeMo KαMo KαMo Kα
µ (mm1)0.060.060.06
Crystal size (mm)1.00 × 0.33 (radius)0.35 × 0.15 (radius)0.35 × 0.15 (radius)
Data collection
DiffractometerBruker SMART APEX CCD area-detector
diffractometer
Bruker Nonius X8 APEXII CCD area-detector
diffractometer
Bruker Nonius X8 APEXII CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2003)
Multi-scan
(SADABS; Bruker, 2003)
Multi-scan
(SADABS; Bruker, 2003)
Tmin, Tmax0.688, 0.9600.853, 0.9770.688, 0.981
No. of measured, independent and
observed [I > 2σ(I)] reflections
4439, 1782, 1144 5429, 900, 760 16092, 2509, 1824
Rint0.0350.0260.051
(sin θ/λ)max1)0.6670.6180.614
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.056, 0.162, 1.04 0.042, 0.110, 1.06 0.083, 0.269, 1.12
No. of reflections17829002509
No. of parameters8350173
No. of restraints0014
H-atom treatmentH atoms treated by a mixture of independent and constrained refinementH atoms treated by a mixture of independent and constrained refinementH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.18, 0.180.16, 0.130.29, 0.22

Computer programs: SMART (Bruker, 1997), APEX2 (Bruker, 2004), SAINT (Bruker, 2003), SIR92 (Altomare et al., 1994), SHELXTL (Sheldrick, 2008) and Mercury (Macrae et al., 2006).

Hydrogen-bond geometry (Å, º) for (I) top
D—H···AD—HH···AD···AD—H···A
N5—H5···N10.86 (2)2.27 (2)3.120 (2)171.5 (15)
N1—H1···N5i0.87 (2)2.24 (2)3.102 (2)174.4 (16)
Symmetry code: (i) x+1, y+1/2, z+1/2.
Hydrogen-bond geometry (Å, º) for (II) top
D—H···AD—HH···AD···AD—H···A
N1—H1···N1i0.84 (2)2.35 (2)3.1716 (13)163.7 (15)
Symmetry code: (i) x, y1/2, z+1/2.
Hydrogen-bond geometry (Å, º) for (III) top
D—H···AD—HH···AD···AD—H···A
N8—H8···N10.90 (3)2.27 (3)3.167 (3)176 (3)
N1—H1···N8i0.90 (2)2.25 (3)3.150 (3)175 (2)
Symmetry code: (i) x+1, y+1, z.
 

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