A monoclinic polymorph of N,N′-bis­(2,6-diisopropyl­phen­yl)formamidine

Masuda, J.D.

doi:10.1107/S160053680802076X

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Volume 64| Part 8| August 2008| Page o1447

doi:10.1107/S160053680802076X

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A monoclinic polymorph of N,N′-bis(2,6-diisopropylphenyl)formamidine

Jason D. Masuda ^a ^*

^aDepartment of Chemistry, Saint Mary's University, Halifax, Nova Scotia, Canada B3H 3C3
^*Correspondence e-mail: jason.masuda@smu.ca

(Received 24 June 2008; accepted 4 July 2008; online 9 July 2008)

A new polymorph of N,N′-bis(2,6-diisopropylphenyl)formamidine, C₂₅H₃₆N₂, is reported, which is different from the previously reported orthorhombic structure. The molecule crystallizes in the E–anti configuration, with tautomeric disorder of the N-bonded H atoms and no clear distinction between imine and amine functionalities. The molecules form hydrogen-bonded dimers with intermolecular N⋯N distances shorter than those in the orthorhombic polymorph.

Related literature

For the orthorhombic polymorph, see: Stibrany & Potenza (2006 ). For synthetic details and related literature, see: Krahulic et al. (2005 ); Perrin (1991 ).

Experimental

Crystal data

C₂₅H₃₆N₂
M_r = 364.56
Monoclinic, C 2/c
a = 24.169 (4) Å
b = 12.7881 (18) Å
c = 19.479 (3) Å
β = 126.735 (2)°
V = 4824.8 (12) Å³
Z = 8
Mo Kα radiation
μ = 0.06 mm⁻¹
T = 291 (2) K
0.45 × 0.34 × 0.30 mm

Data collection

Bruker SMART 1K CCD diffractometer
Absorption correction: none
12048 measured reflections
4242 independent reflections
2237 reflections with I > 2σ(I)
R_int = 0.036

Refinement

R[F² > 2σ(F²)] = 0.051
wR(F²) = 0.161
S = 1.02
4242 reflections
252 parameters
H-atom parameters constrained
Δρ_max = 0.18 e Å⁻³
Δρ_min = −0.17 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯N1ⁱ	0.86	2.03	2.882 (4)	171
N2—H2A⋯N2ⁱ	0.86	2.05	2.910 (3)	175
Symmetry code: (i) $[-x, y, -z+{\script{3\over 2}}]$ .

Data collection: SMART (Bruker, 2003 ); cell refinement: SAINT (Bruker, 2003); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ); software used to prepare material for publication: publCIF (Westrip, 2008 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S160053680802076X/bi2287sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S160053680802076X/bi2287Isup2.hkl

checkCIF report

Comment top

Crystals of the title compound were grown from toluene solution and were found to crystallize in the monoclinic space group C2/c, different from the previously published polymorph which crystallizes in the orthorhombic space group C222₁ (Stibrany & Potenza, 2006). The molecule crystallizes in the E-anti configuration (Perrin, 1991), with tautomeric disorder of the N-bonded H atoms. The molecules form hydrogen-bonded dimers with N···N distances of 2.882 (4) and 2.910 (3) Å (Table 1). These distances are slightly shorter than that seen in the orthorhombic polymorph (2.947 Å). The two core amidine (NCNH) fragments are non-coplanar as a result of interaction between the sterically bulky 2,6-diisopropylphenyl fragments. The N1—C(1) (1.313 (3) Å) and N2—C1 (1.311 (3) Å) distances are similar in length, whereas in the orthorhombic polymorph there are distinct imine (1.288 Å) and amine (1.325 Å) functionalities.

Related literature top

For the orthorhombic polymorph, see: Stibrany & Potenza (2006). For synthesis details and related literature, see: Krahulic et al. (2005); Perrin (1991).

Experimental top

The title compound was prepared according to the literature procedure (Krahulic et al., 2005). Crystals were grown by evaporation of a toluene solution at room temperature.

Computing details top

Data collection: SMART (Bruker, 2003); cell refinement: SAINT (Bruker, 2003); data reduction: SAINT (Bruker, 2003); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: publCIF (Westrip, 2008).

Figures top

	Fig. 1. Molecular structure showing displacement ellipsoids at the 30% probability level for non-H atoms. H atoms bound to C (except for H1) are omitted, and only one of the disordered H atoms (H1A & H1B) is shown.
	Fig. 2. A plot of the hydrogen-bonded dimer in the title compound, showing displacement ellipsoids at the 30% probability level for non-H atoms. H atoms bound to C (except for H1) are omitted, and only one of the disordered H atoms (H1A & H1B) is shown.

N,N'-bis(2,6-diisopropylphenyl)formamidine top

Crystal data top

C₂₅H₃₆N₂	F(000) = 1600
M_r = 364.56	D_x = 1.004 Mg m⁻³
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 2205 reflections
a = 24.169 (4) Å	θ = 2.6–21.8°
b = 12.7881 (18) Å	µ = 0.06 mm⁻¹
c = 19.479 (3) Å	T = 291 K
β = 126.735 (2)°	Block, colourless
V = 4824.8 (12) Å³	0.45 × 0.34 × 0.30 mm
Z = 8

Data collection top

Bruker SMART 1K CCD diffractometer	2237 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.036
Graphite monochromator	θ_max = 25.0°, θ_min = 2.1°
ϕ and ω scans	h = −28→28
12048 measured reflections	k = −7→15
4242 independent reflections	l = −23→23

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.051	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.161	H-atom parameters constrained
S = 1.02	w = 1/[σ²(F_o²) + (0.065P)² + 2.1873P] where P = (F_o² + 2F_c²)/3
4242 reflections	(Δ/σ)_max < 0.001
252 parameters	Δρ_max = 0.18 e Å⁻³
0 restraints	Δρ_min = −0.17 e Å⁻³

Crystal data top

C₂₅H₃₆N₂	V = 4824.8 (12) Å³
M_r = 364.56	Z = 8
Monoclinic, C2/c	Mo Kα radiation
a = 24.169 (4) Å	µ = 0.06 mm⁻¹
b = 12.7881 (18) Å	T = 291 K
c = 19.479 (3) Å	0.45 × 0.34 × 0.30 mm
β = 126.735 (2)°

Data collection top

Bruker SMART 1K CCD diffractometer	2237 reflections with I > 2σ(I)
12048 measured reflections	R_int = 0.036
4242 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.051	0 restraints
wR(F²) = 0.161	H-atom parameters constrained
S = 1.02	Δρ_max = 0.18 e Å⁻³
4242 reflections	Δρ_min = −0.17 e Å⁻³
252 parameters

Special details top

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

	x	y	z	U_iso*/U_eq	Occ. (<1)
N2	0.02590 (9)	0.18752 (13)	0.69910 (11)	0.0465 (5)
H2A	0.0113	0.1919	0.7299	0.056*	0.50
N1	0.00186 (10)	0.01071 (13)	0.67743 (12)	0.0502 (5)
H1A	−0.0042	0.0087	0.7167	0.060*	0.50
C2	−0.00791 (13)	−0.08218 (17)	0.63024 (16)	0.0509 (6)
C1	0.01996 (11)	0.09893 (17)	0.66139 (14)	0.0468 (6)
H1	0.0290	0.0985	0.6212	0.056*
C14	0.05632 (11)	0.27673 (17)	0.68974 (14)	0.0463 (6)
C15	0.01510 (13)	0.36571 (18)	0.64789 (15)	0.0554 (6)
C19	0.12706 (12)	0.27631 (19)	0.72640 (16)	0.0569 (6)
C7	0.03995 (14)	−0.16434 (18)	0.67252 (17)	0.0607 (7)
C3	−0.06573 (14)	−0.0910 (2)	0.54441 (16)	0.0612 (7)
C11	0.10007 (15)	−0.1590 (2)	0.76716 (17)	0.0705 (8)
H11A	0.0904	−0.1015	0.7917	0.085*
C8	−0.12183 (15)	−0.0076 (2)	0.50015 (18)	0.0746 (8)
H8A	−0.1093	0.0474	0.5422	0.090*
C6	0.03099 (18)	−0.2520 (2)	0.6239 (2)	0.0797 (9)
H6A	0.0627	−0.3064	0.6499	0.096*
C4	−0.07140 (17)	−0.1813 (2)	0.50041 (19)	0.0781 (9)
H4A	−0.1090	−0.1884	0.4432	0.094*
C20	−0.06095 (13)	0.3655 (2)	0.60888 (18)	0.0692 (8)
H20A	−0.0673	0.3122	0.6397	0.083*
C16	0.04601 (16)	0.4528 (2)	0.64050 (19)	0.0776 (8)
H16A	0.0196	0.5120	0.6120	0.093*
C17	0.11450 (18)	0.4525 (2)	0.6744 (2)	0.0902 (10)
H17A	0.1341	0.5113	0.6688	0.108*
C23	0.17226 (13)	0.1832 (2)	0.77905 (18)	0.0719 (8)
H23A	0.1449	0.1200	0.7502	0.086*
C18	0.15455 (15)	0.3660 (2)	0.7168 (2)	0.0803 (9)
H18A	0.2011	0.3673	0.7396	0.096*
C5	−0.0236 (2)	−0.2596 (2)	0.5387 (2)	0.0874 (10)
H5A	−0.0279	−0.3179	0.5072	0.105*
C25	0.23851 (14)	0.1727 (3)	0.7863 (2)	0.0935 (10)
H25A	0.2276	0.1749	0.7302	0.140*
H25B	0.2605	0.1074	0.8133	0.140*
H25C	0.2691	0.2293	0.8201	0.140*
C13	0.10778 (19)	−0.2581 (3)	0.8163 (2)	0.1084 (12)
H13A	0.1433	−0.2478	0.8764	0.163*
H13B	0.1200	−0.3158	0.7963	0.163*
H13C	0.0649	−0.2730	0.8071	0.163*
C12	0.16764 (18)	−0.1332 (3)	0.7815 (2)	0.1097 (12)
H12A	0.1630	−0.0682	0.7539	0.165*
H12B	0.1788	−0.1879	0.7579	0.165*
H12C	0.2038	−0.1273	0.8418	0.165*
C10	−0.12660 (19)	0.0421 (3)	0.4259 (2)	0.1045 (11)
H10A	−0.0823	0.0697	0.4461	0.157*
H10B	−0.1599	0.0976	0.4021	0.157*
H10C	−0.1406	−0.0097	0.3827	0.157*
C24	0.18908 (18)	0.1848 (3)	0.8679 (2)	0.1184 (14)
H24A	0.1470	0.1816	0.8627	0.178*
H24B	0.2133	0.2482	0.8968	0.178*
H24C	0.2175	0.1258	0.9002	0.178*
C21	−0.08718 (19)	0.4678 (3)	0.6196 (3)	0.1195 (13)
H21A	−0.0574	0.4892	0.6785	0.179*
H21B	−0.1332	0.4581	0.6026	0.179*
H21C	−0.0875	0.5207	0.5844	0.179*
C9	−0.19216 (18)	−0.0515 (3)	0.4695 (3)	0.1260 (14)
H9A	−0.1900	−0.0740	0.5181	0.189*
H9B	−0.2038	−0.1099	0.4321	0.189*
H9C	−0.2267	0.0018	0.4392	0.189*
C22	−0.10306 (17)	0.3317 (4)	0.5178 (2)	0.1415 (17)
H22A	−0.0855	0.2666	0.5135	0.212*
H22B	−0.1007	0.3839	0.4842	0.212*
H22C	−0.1502	0.3226	0.4969	0.212*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N2	0.0542 (12)	0.0376 (11)	0.0561 (12)	−0.0011 (9)	0.0376 (10)	−0.0006 (9)
N1	0.0740 (14)	0.0368 (11)	0.0566 (12)	0.0004 (10)	0.0481 (11)	−0.0005 (9)
C2	0.0741 (17)	0.0376 (13)	0.0615 (16)	−0.0029 (12)	0.0516 (15)	−0.0020 (12)
C1	0.0513 (14)	0.0483 (14)	0.0475 (13)	0.0015 (11)	0.0330 (12)	0.0025 (12)
C14	0.0511 (14)	0.0420 (13)	0.0495 (13)	−0.0059 (11)	0.0322 (12)	−0.0040 (11)
C15	0.0612 (16)	0.0429 (14)	0.0589 (16)	−0.0023 (12)	0.0342 (14)	0.0009 (12)
C19	0.0550 (16)	0.0551 (15)	0.0616 (16)	−0.0068 (13)	0.0355 (13)	−0.0058 (13)
C7	0.089 (2)	0.0415 (14)	0.0725 (18)	0.0033 (14)	0.0599 (17)	0.0001 (13)
C3	0.0817 (19)	0.0557 (16)	0.0582 (17)	−0.0070 (14)	0.0483 (16)	−0.0065 (14)
C11	0.090 (2)	0.0576 (17)	0.074 (2)	0.0200 (15)	0.0539 (18)	0.0119 (15)
C8	0.078 (2)	0.080 (2)	0.0591 (17)	−0.0008 (17)	0.0373 (16)	−0.0067 (15)
C6	0.120 (3)	0.0427 (16)	0.100 (3)	0.0088 (16)	0.079 (2)	−0.0006 (16)
C4	0.106 (2)	0.069 (2)	0.0666 (19)	−0.0134 (18)	0.0555 (18)	−0.0150 (17)
C20	0.0616 (17)	0.0590 (17)	0.079 (2)	0.0106 (14)	0.0379 (16)	0.0132 (15)
C16	0.086 (2)	0.0506 (16)	0.095 (2)	−0.0034 (15)	0.0534 (19)	0.0093 (16)
C17	0.093 (2)	0.0605 (19)	0.125 (3)	−0.0231 (18)	0.069 (2)	0.003 (2)
C23	0.0534 (16)	0.0719 (18)	0.083 (2)	0.0030 (14)	0.0369 (15)	0.0051 (16)
C18	0.0636 (18)	0.076 (2)	0.101 (2)	−0.0171 (16)	0.0493 (18)	−0.0044 (18)
C5	0.139 (3)	0.0538 (19)	0.096 (3)	−0.009 (2)	0.084 (2)	−0.0201 (18)
C25	0.0622 (18)	0.117 (3)	0.094 (2)	0.0095 (18)	0.0426 (17)	−0.009 (2)
C13	0.146 (3)	0.089 (2)	0.107 (3)	0.024 (2)	0.085 (3)	0.034 (2)
C12	0.099 (3)	0.127 (3)	0.105 (3)	0.010 (2)	0.062 (2)	0.019 (2)
C10	0.127 (3)	0.099 (3)	0.088 (2)	0.021 (2)	0.064 (2)	0.022 (2)
C24	0.097 (2)	0.168 (4)	0.099 (3)	0.056 (3)	0.063 (2)	0.052 (3)
C21	0.109 (3)	0.097 (3)	0.158 (4)	0.034 (2)	0.084 (3)	0.006 (3)
C9	0.096 (3)	0.149 (4)	0.137 (3)	−0.001 (3)	0.071 (3)	0.009 (3)
C22	0.067 (2)	0.214 (5)	0.096 (3)	0.005 (3)	0.023 (2)	−0.040 (3)

Geometric parameters (Å, º) top

N2—C1	1.310 (3)	C16—H16A	0.930
N2—C14	1.427 (3)	C17—C18	1.373 (4)
N2—H2A	0.860	C17—H17A	0.930
N1—C1	1.313 (3)	C23—C24	1.523 (4)
N1—C2	1.432 (3)	C23—C25	1.527 (4)
N1—H1A	0.860	C23—H23A	0.980
C2—C3	1.402 (3)	C18—H18A	0.930
C2—C7	1.407 (3)	C5—H5A	0.930
C1—H1	0.930	C25—H25A	0.960
C14—C19	1.404 (3)	C25—H25B	0.960
C14—C15	1.407 (3)	C25—H25C	0.960
C15—C16	1.395 (3)	C13—H13A	0.960
C15—C20	1.512 (3)	C13—H13B	0.960
C19—C18	1.392 (3)	C13—H13C	0.960
C19—C23	1.524 (3)	C12—H12A	0.960
C7—C6	1.398 (3)	C12—H12B	0.960
C7—C11	1.520 (4)	C12—H12C	0.960
C3—C4	1.395 (4)	C10—H10A	0.960
C3—C8	1.523 (4)	C10—H10B	0.960
C11—C12	1.519 (4)	C10—H10C	0.960
C11—C13	1.531 (4)	C24—H24A	0.960
C11—H11A	0.980	C24—H24B	0.960
C8—C10	1.520 (4)	C24—H24C	0.960
C8—C9	1.532 (4)	C21—H21A	0.960
C8—H8A	0.980	C21—H21B	0.960
C6—C5	1.373 (4)	C21—H21C	0.960
C6—H6A	0.930	C9—H9A	0.960
C4—C5	1.365 (4)	C9—H9B	0.960
C4—H4A	0.930	C9—H9C	0.960
C20—C22	1.487 (4)	C22—H22A	0.960
C20—C21	1.522 (4)	C22—H22B	0.960
C20—H20A	0.980	C22—H22C	0.960
C16—C17	1.367 (4)

C1—N2—C14	120.78 (18)	C19—C23—C25	114.9 (2)
C1—N2—H2A	119.6	C24—C23—H23A	107.0
C14—N2—H2A	119.6	C19—C23—H23A	107.0
C1—N1—C2	120.68 (18)	C25—C23—H23A	107.0
C1—N1—H1A	119.7	C17—C18—C19	121.5 (3)
C2—N1—H1A	119.7	C17—C18—H18A	119.3
C3—C2—C7	121.5 (2)	C19—C18—H18A	119.3
C3—C2—N1	119.7 (2)	C4—C5—C6	119.7 (3)
C7—C2—N1	118.8 (2)	C4—C5—H5A	120.2
N2—C1—N1	123.3 (2)	C6—C5—H5A	120.2
N2—C1—H1	118.3	C23—C25—H25A	109.5
N1—C1—H1	118.3	C23—C25—H25B	109.5
C19—C14—C15	121.5 (2)	H25A—C25—H25B	109.5
C19—C14—N2	119.7 (2)	C23—C25—H25C	109.5
C15—C14—N2	118.7 (2)	H25A—C25—H25C	109.5
C16—C15—C14	117.9 (2)	H25B—C25—H25C	109.5
C16—C15—C20	121.0 (2)	C11—C13—H13A	109.5
C14—C15—C20	121.1 (2)	C11—C13—H13B	109.5
C18—C19—C14	117.5 (2)	H13A—C13—H13B	109.5
C18—C19—C23	121.8 (2)	C11—C13—H13C	109.5
C14—C19—C23	120.6 (2)	H13A—C13—H13C	109.5
C6—C7—C2	117.5 (3)	H13B—C13—H13C	109.5
C6—C7—C11	120.4 (3)	C11—C12—H12A	109.5
C2—C7—C11	122.1 (2)	C11—C12—H12B	109.5
C4—C3—C2	117.4 (3)	H12A—C12—H12B	109.5
C4—C3—C8	120.3 (3)	C11—C12—H12C	109.5
C2—C3—C8	122.2 (2)	H12A—C12—H12C	109.5
C12—C11—C7	112.1 (2)	H12B—C12—H12C	109.5
C12—C11—C13	110.4 (3)	C8—C10—H10A	109.5
C7—C11—C13	113.1 (3)	C8—C10—H10B	109.5
C12—C11—H11A	107.0	H10A—C10—H10B	109.5
C7—C11—H11A	107.0	C8—C10—H10C	109.5
C13—C11—H11A	107.0	H10A—C10—H10C	109.5
C10—C8—C3	111.5 (3)	H10B—C10—H10C	109.5
C10—C8—C9	110.4 (3)	C23—C24—H24A	109.5
C3—C8—C9	111.6 (3)	C23—C24—H24B	109.5
C10—C8—H8A	107.7	H24A—C24—H24B	109.5
C3—C8—H8A	107.7	C23—C24—H24C	109.5
C9—C8—H8A	107.7	H24A—C24—H24C	109.5
C5—C6—C7	121.6 (3)	H24B—C24—H24C	109.5
C5—C6—H6A	119.2	C20—C21—H21A	109.5
C7—C6—H6A	119.2	C20—C21—H21B	109.5
C5—C4—C3	122.1 (3)	H21A—C21—H21B	109.5
C5—C4—H4A	118.9	C20—C21—H21C	109.5
C3—C4—H4A	118.9	H21A—C21—H21C	109.5
C22—C20—C15	111.0 (2)	H21B—C21—H21C	109.5
C22—C20—C21	111.7 (3)	C8—C9—H9A	109.5
C15—C20—C21	114.2 (2)	C8—C9—H9B	109.5
C22—C20—H20A	106.4	H9A—C9—H9B	109.5
C15—C20—H20A	106.4	C8—C9—H9C	109.5
C21—C20—H20A	106.4	H9A—C9—H9C	109.5
C17—C16—C15	121.1 (3)	H9B—C9—H9C	109.5
C17—C16—H16A	119.5	C20—C22—H22A	109.5
C15—C16—H16A	119.5	C20—C22—H22B	109.5
C16—C17—C18	120.5 (3)	H22A—C22—H22B	109.5
C16—C17—H17A	119.7	C20—C22—H22C	109.5
C18—C17—H17A	119.7	H22A—C22—H22C	109.5
C24—C23—C19	110.5 (2)	H22B—C22—H22C	109.5
C24—C23—C25	110.1 (2)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···N1ⁱ	0.86	2.03	2.882 (4)	171
N2—H2A···N2ⁱ	0.86	2.05	2.910 (3)	175

Symmetry code: (i) −x, y, −z+3/2.

Experimental details

Crystal data
Chemical formula	C₂₅H₃₆N₂
M_r	364.56
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	291
a, b, c (Å)	24.169 (4), 12.7881 (18), 19.479 (3)
β (°)	126.735 (2)
V (Å³)	4824.8 (12)
Z	8
Radiation type	Mo Kα
µ (mm⁻¹)	0.06
Crystal size (mm)	0.45 × 0.34 × 0.30

Data collection
Diffractometer	Bruker SMART 1K CCD diffractometer
Absorption correction	–
No. of measured, independent and observed [I > 2σ(I)] reflections	12048, 4242, 2237
R_int	0.036
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.051, 0.161, 1.02
No. of reflections	4242
No. of parameters	252
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.18, −0.17

Computer programs: SMART (Bruker, 2003), SAINT (Bruker, 2003), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997), publCIF (Westrip, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···N1ⁱ	0.86	2.03	2.882 (4)	170.6
N2—H2A···N2ⁱ	0.86	2.05	2.910 (3)	174.5

Symmetry code: (i) −x, y, −z+3/2.

Acknowledgements

The author thanks Saint Mary's University for funding.

References

Bruker (2003). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565. CrossRef IUCr Journals Google Scholar
Krahulic, K. E., Enright, G. D., Parvez, M. & Roesler, R. (2005). J. Am. Chem. Soc. 127, 4142–4143. Web of Science CSD CrossRef PubMed CAS Google Scholar
Perrin, C. L. (1991). The Chemistry of Amidines and Imidates, Vol. 2, edited by S. Patai & Z. Rappoport, pp. 147–229. Chichester: Wiley. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Stibrany, R. T. & Potenza, J. A. (2006). Private communication (refcode: TEVJOU). CCDC, Cambridge, England. Google Scholar
Westrip, S. J. (2008). publCIF. In preparation. Google Scholar