N-Butyl-4-butyl­amino-1,8-naphthalimide

The crystal structure of the title compound, C₂₀H₂₄N₂O₂, establishes the intra­molecular charge transfer state as the lowest electronic state in the mol­ecule. The mol­ecules are held together by inter­molecular N—H...O hydrogen bonds, giving rise to a polymeric chain.

Key indicators

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](C-C)= 0.002 Å
• R factor = 0.048
• wR factor = 0.126
• Data-to-parameter ratio = 18.1

checkCIF/PLATON results

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S1. Comment

4-Amino-1,8-naphthalimide and its derivatives possess conjugating electron donor and acceptor groups and therefore they are expected to have an intramolecular charge transfer (ICT) state as the lowest electronic state. This CT nature for the molecules has been elucidated by various photophysical studies. Crystal structures of such compounds are also equally important to understand their ground-state properties (Banthia & Samanta, 2005). The crystal structure of the title compound, (I) (Fig. 1), reported here, supports very well the existence of a CT character in the molecule. The short C4—N1 bond length, 1.3521 (15) Å, and bond angles around the amino N atom close to 120° (Table 1), suggest considerable double-bond character for the C—N bond, manifesting CT character in the ground state.

In the packing structure of (I), shown in Fig. 2, an intermolecular N1—H1···O1 hydrogen bond connects the translated molecules, leading to an infinite polymeric chain. Atom N1 of the amino group acts as a hydrogen-bond donor to atom O1 of a symmetry-related molecule (Table 2).

S2. Experimental

The title compound was prepared according to standard procedures (Banthia et al., 2005). Single crystals suitable for the X-ray diffraction study were grown by slow evaporation of a solution of (I) in chloroform.

S3. Refinement

The H atom attached to the amine N atom was located in a difference map and refined without any restraint, with U_iso(H) = 1.5U_eq(N). Other H atoms were included in the refinement at calculated positions and refined as riding to their carrier atoms, with C—H set to 0.93 (aromatic), 0.97 (CH₂) or 0.96 Å (CH₃), and with displacement parameters set to be isotropic with a value equal to 1.2 (aromatic CH, CH₂) or 1.5 (CH₃) times U_eq of the parent C atom.

Computing details

Data collection: SMART (Bruker, 2003); cell refinement: SAINT (Bruker, 2003); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and Mercury (Bruno et al., 2002); software used to prepare material for publication: SHELXTL (Bruker 2003).

Figures

	Fig. 1. An ORTEP-3 (Farrugia, 1997) view of the molecular structure of (I), with displacement ellipsoids drawn at the 50% probability level. H atoms are shown as small spheres of arbitrary radii.
	Fig. 2. Packing diagrams of (I), illustrating the intermolecular hydorgen bonding, shown as dashed lines, between the amine and the carbonyl groups. H atoms have been omitted for clarity.

N-butyl-4-butylaminonaphthalimide

Crystal data

C20H24N2O2	F(000) = 1392
Mr = 324.41	Dx = 1.283 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 6924 reflections
a = 27.886 (3) Å	θ = 2.5–28.2°
b = 8.0475 (9) Å	µ = 0.08 mm^−1
c = 16.671 (2) Å	T = 100 K
β = 116.149 (2)°	Plate, yellow
V = 3358.3 (7) Å^3	0.60 × 0.18 × 0.06 mm
Z = 8

Data collection

Bruker SMART CCD area-detector diffractometer	4026 independent reflections
Radiation source: fine-focus sealed tube	3477 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.031
ϕ and ω scans	θmax = 28.3°, θmin = 1.6°
Absorption correction: multi-scan (SADABS; Sheldrick, 2002)	h = −36→36
Tmin = 0.856, Tmax = 0.995	k = −10→10
18639 measured reflections	l = −21→21

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.048	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.126	H atoms treated by a mixture of independent and constrained refinement
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0675P)^2 + 2.4226P] where P = (Fo^2 + 2Fc^2)/3
4026 reflections	(Δ/σ)max < 0.001
223 parameters	Δρmax = 0.44 e Å^−3
0 restraints	Δρmin = −0.22 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
O1	0.17524 (3)	0.86273 (12)	0.12282 (6)	0.0212 (2)
O2	0.03610 (3)	0.61602 (11)	0.14827 (6)	0.0200 (2)
N1	0.24503 (4)	1.00267 (13)	0.53713 (7)	0.0164 (2)
H1	0.2226 (7)	1.008 (2)	0.5609 (11)	0.030 (4)*
N2	0.10750 (4)	0.73121 (13)	0.13764 (6)	0.0159 (2)
C1	0.17877 (5)	0.86185 (15)	0.26753 (8)	0.0149 (2)
C2	0.22741 (5)	0.94240 (15)	0.30787 (8)	0.0168 (2)
H2	0.2453	0.9681	0.2738	0.020*
C3	0.25042 (5)	0.98621 (15)	0.39762 (8)	0.0165 (2)
H3	0.2838	1.0371	0.4228	0.020*
C4	0.22404 (5)	0.95478 (14)	0.45059 (8)	0.0148 (2)
C5	0.14508 (5)	0.82440 (15)	0.46062 (8)	0.0167 (3)
H5	0.1588	0.8542	0.5205	0.020*
C6	0.09763 (5)	0.73875 (16)	0.42156 (8)	0.0181 (3)
H6	0.0797	0.7111	0.4553	0.022*
C7	0.07617 (5)	0.69288 (15)	0.33132 (8)	0.0167 (2)
H7	0.0441	0.6346	0.3054	0.020*
C8	0.10261 (5)	0.73431 (14)	0.28098 (7)	0.0146 (2)
C9	0.15164 (5)	0.82144 (14)	0.31974 (7)	0.0138 (2)
C10	0.17342 (5)	0.86788 (14)	0.41129 (8)	0.0144 (2)
C11	0.15529 (5)	0.82167 (15)	0.17262 (8)	0.0158 (2)
C12	0.07877 (5)	0.68785 (14)	0.18541 (8)	0.0154 (2)
C13	0.08263 (5)	0.69190 (16)	0.04126 (8)	0.0176 (3)
H13A	0.0628	0.5887	0.0311	0.021*
H13B	0.1103	0.6766	0.0217	0.021*
C14	0.04520 (5)	0.82971 (15)	−0.01308 (8)	0.0182 (3)
H14A	0.0652	0.9326	−0.0025	0.022*
H14B	0.0178	0.8451	0.0072	0.022*
C15	0.01858 (5)	0.79369 (16)	−0.11300 (8)	0.0198 (3)
H15A	0.0458	0.7771	−0.1335	0.024*
H15B	−0.0021	0.6922	−0.1241	0.024*
C16	−0.01788 (5)	0.93586 (16)	−0.16514 (8)	0.0208 (3)
H16A	−0.0432	0.9578	−0.1419	0.031*
H16B	−0.0365	0.9058	−0.2271	0.031*
H16C	0.0031	1.0336	−0.1593	0.031*
C17	0.29650 (5)	1.08537 (15)	0.58329 (8)	0.0160 (2)
H17A	0.2957	1.1919	0.5555	0.019*
H17B	0.3244	1.0180	0.5798	0.019*
C18	0.30779 (5)	1.11039 (15)	0.68028 (7)	0.0159 (2)
H18A	0.3082	1.0026	0.7066	0.019*
H18B	0.2787	1.1740	0.6821	0.019*
C19	0.36006 (5)	1.19867 (15)	0.73710 (8)	0.0174 (3)
H19A	0.3603	1.3066	0.7114	0.021*
H19B	0.3897	1.1344	0.7378	0.021*
C20	0.36679 (5)	1.22040 (17)	0.83249 (8)	0.0229 (3)
H20A	0.3392	1.2920	0.8322	0.034*
H20B	0.4011	1.2688	0.8687	0.034*
H20C	0.3644	1.1140	0.8565	0.034*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0223 (5)	0.0305 (5)	0.0135 (4)	−0.0019 (4)	0.0103 (4)	0.0001 (4)
O2	0.0196 (4)	0.0232 (5)	0.0154 (4)	−0.0034 (3)	0.0060 (4)	−0.0015 (3)
N1	0.0169 (5)	0.0215 (5)	0.0116 (5)	−0.0020 (4)	0.0070 (4)	−0.0022 (4)
N2	0.0186 (5)	0.0192 (5)	0.0095 (5)	0.0004 (4)	0.0058 (4)	−0.0005 (4)
C1	0.0178 (6)	0.0161 (6)	0.0119 (5)	0.0021 (4)	0.0074 (5)	0.0009 (4)
C2	0.0196 (6)	0.0200 (6)	0.0147 (6)	0.0005 (5)	0.0110 (5)	0.0007 (4)
C3	0.0158 (5)	0.0191 (6)	0.0148 (6)	−0.0018 (4)	0.0069 (5)	−0.0012 (4)
C4	0.0167 (6)	0.0146 (5)	0.0125 (5)	0.0029 (4)	0.0056 (4)	0.0009 (4)
C5	0.0195 (6)	0.0196 (6)	0.0121 (5)	0.0017 (4)	0.0079 (5)	0.0006 (4)
C6	0.0199 (6)	0.0223 (6)	0.0156 (6)	0.0018 (5)	0.0109 (5)	0.0031 (5)
C7	0.0149 (5)	0.0190 (6)	0.0153 (6)	−0.0002 (4)	0.0059 (5)	0.0017 (4)
C8	0.0168 (6)	0.0146 (5)	0.0120 (5)	0.0025 (4)	0.0061 (4)	0.0014 (4)
C9	0.0166 (5)	0.0132 (5)	0.0121 (5)	0.0036 (4)	0.0067 (4)	0.0019 (4)
C10	0.0172 (6)	0.0141 (5)	0.0121 (5)	0.0024 (4)	0.0067 (4)	0.0010 (4)
C11	0.0172 (6)	0.0176 (6)	0.0137 (5)	0.0026 (4)	0.0078 (5)	0.0007 (4)
C12	0.0177 (6)	0.0151 (6)	0.0134 (5)	0.0027 (4)	0.0069 (5)	0.0024 (4)
C13	0.0209 (6)	0.0211 (6)	0.0099 (5)	0.0003 (5)	0.0060 (5)	−0.0016 (4)
C14	0.0226 (6)	0.0200 (6)	0.0109 (5)	−0.0003 (5)	0.0062 (5)	−0.0010 (4)
C15	0.0238 (6)	0.0223 (6)	0.0121 (5)	0.0005 (5)	0.0069 (5)	−0.0014 (5)
C16	0.0224 (6)	0.0246 (6)	0.0139 (6)	−0.0002 (5)	0.0066 (5)	0.0003 (5)
C17	0.0173 (6)	0.0173 (6)	0.0130 (5)	−0.0001 (4)	0.0064 (4)	−0.0009 (4)
C18	0.0183 (6)	0.0169 (6)	0.0128 (5)	0.0003 (4)	0.0073 (5)	0.0001 (4)
C19	0.0205 (6)	0.0181 (6)	0.0129 (5)	−0.0008 (5)	0.0067 (5)	−0.0008 (4)
C20	0.0277 (7)	0.0252 (7)	0.0139 (6)	−0.0039 (5)	0.0076 (5)	−0.0023 (5)

Geometric parameters (Å, º)

O1—C11	1.2309 (14)	C9—C10	1.4216 (15)
O2—C12	1.2183 (15)	C13—C14	1.5187 (17)
N1—C4	1.3521 (15)	C13—H13A	0.9700
N1—C17	1.4564 (15)	C13—H13B	0.9700
N1—H1	0.877 (18)	C14—C15	1.5231 (16)
N2—C12	1.4001 (15)	C14—H14A	0.9700
N2—C11	1.4003 (15)	C14—H14B	0.9700
N2—C13	1.4767 (14)	C15—C16	1.5229 (17)
C1—C2	1.3813 (17)	C15—H15A	0.9700
C1—C9	1.4197 (16)	C15—H15B	0.9700
C1—C11	1.4574 (16)	C16—H16A	0.9600
C2—C3	1.3888 (16)	C16—H16B	0.9600
C2—H2	0.9300	C16—H16C	0.9600
C3—C4	1.3991 (17)	C17—C18	1.5183 (15)
C3—H3	0.9300	C17—H17A	0.9700
C4—C10	1.4477 (16)	C17—H17B	0.9700
C5—C6	1.3750 (17)	C18—C19	1.5197 (16)
C5—C10	1.4127 (16)	C18—H18A	0.9700
C5—H5	0.9300	C18—H18B	0.9700
C6—C7	1.4014 (16)	C19—C20	1.5270 (16)
C6—H6	0.9300	C19—H19A	0.9700
C7—C8	1.3801 (16)	C19—H19B	0.9700
C7—H7	0.9300	C20—H20A	0.9600
C8—C9	1.4142 (16)	C20—H20B	0.9600
C8—C12	1.4788 (16)	C20—H20C	0.9600
C4—N1—C17	123.82 (10)	N2—C13—H13B	109.4
C4—N1—H1	115.9 (11)	C14—C13—H13B	109.4
C17—N1—H1	118.1 (11)	H13A—C13—H13B	108.0
C12—N2—C11	124.81 (10)	C13—C14—C15	112.88 (10)
C12—N2—C13	116.95 (10)	C13—C14—H14A	109.0
C11—N2—C13	117.96 (9)	C15—C14—H14A	109.0
C2—C1—C9	118.90 (10)	C13—C14—H14B	109.0
C2—C1—C11	120.50 (10)	C15—C14—H14B	109.0
C9—C1—C11	120.59 (11)	H14A—C14—H14B	107.8
C1—C2—C3	122.13 (11)	C16—C15—C14	111.24 (10)
C1—C2—H2	118.9	C16—C15—H15A	109.4
C3—C2—H2	118.9	C14—C15—H15A	109.4
C2—C3—C4	120.82 (11)	C16—C15—H15B	109.4
C2—C3—H3	119.6	C14—C15—H15B	109.4
C4—C3—H3	119.6	H15A—C15—H15B	108.0
N1—C4—C3	121.40 (11)	C15—C16—H16A	109.5
N1—C4—C10	119.87 (10)	C15—C16—H16B	109.5
C3—C4—C10	118.73 (10)	H16A—C16—H16B	109.5
C6—C5—C10	121.12 (11)	C15—C16—H16C	109.5
C6—C5—H5	119.4	H16A—C16—H16C	109.5
C10—C5—H5	119.4	H16B—C16—H16C	109.5
C5—C6—C7	120.46 (11)	N1—C17—C18	108.48 (9)
C5—C6—H6	119.8	N1—C17—H17A	110.0
C7—C6—H6	119.8	C18—C17—H17A	110.0
C8—C7—C6	119.95 (11)	N1—C17—H17B	110.0
C8—C7—H7	120.0	C18—C17—H17B	110.0
C6—C7—H7	120.0	H17A—C17—H17B	108.4
C7—C8—C9	120.67 (11)	C17—C18—C19	114.68 (10)
C7—C8—C12	119.15 (11)	C17—C18—H18A	108.6
C9—C8—C12	120.18 (10)	C19—C18—H18A	108.6
C8—C9—C1	120.17 (10)	C17—C18—H18B	108.6
C8—C9—C10	119.36 (10)	C19—C18—H18B	108.6
C1—C9—C10	120.47 (11)	H18A—C18—H18B	107.6
C5—C10—C9	118.43 (11)	C18—C19—C20	110.28 (10)
C5—C10—C4	122.69 (10)	C18—C19—H19A	109.6
C9—C10—C4	118.87 (10)	C20—C19—H19A	109.6
O1—C11—N2	119.26 (10)	C18—C19—H19B	109.6
O1—C11—C1	123.53 (11)	C20—C19—H19B	109.6
N2—C11—C1	117.21 (10)	H19A—C19—H19B	108.1
O2—C12—N2	120.33 (10)	C19—C20—H20A	109.5
O2—C12—C8	122.83 (11)	C19—C20—H20B	109.5
N2—C12—C8	116.84 (10)	H20A—C20—H20B	109.5
N2—C13—C14	111.25 (10)	C19—C20—H20C	109.5
N2—C13—H13A	109.4	H20A—C20—H20C	109.5
C14—C13—H13A	109.4	H20B—C20—H20C	109.5
C9—C1—C2—C3	−0.50 (18)	C3—C4—C10—C5	177.19 (11)
C11—C1—C2—C3	178.45 (11)	N1—C4—C10—C9	178.86 (10)
C1—C2—C3—C4	−2.11 (19)	C3—C4—C10—C9	−1.62 (17)
C17—N1—C4—C3	−1.73 (18)	C12—N2—C11—O1	−175.01 (11)
C17—N1—C4—C10	177.77 (10)	C13—N2—C11—O1	−1.15 (17)
C2—C3—C4—N1	−177.36 (11)	C12—N2—C11—C1	5.08 (17)
C2—C3—C4—C10	3.13 (18)	C13—N2—C11—C1	178.94 (10)
C10—C5—C6—C7	−0.17 (18)	C2—C1—C11—O1	−3.63 (19)
C5—C6—C7—C8	−0.26 (19)	C9—C1—C11—O1	175.30 (11)
C6—C7—C8—C9	0.66 (18)	C2—C1—C11—N2	176.27 (11)
C6—C7—C8—C12	−178.75 (10)	C9—C1—C11—N2	−4.81 (17)
C7—C8—C9—C1	179.34 (11)	C11—N2—C12—O2	176.29 (11)
C12—C8—C9—C1	−1.26 (17)	C13—N2—C12—O2	2.37 (16)
C7—C8—C9—C10	−0.63 (17)	C11—N2—C12—C8	−3.34 (17)
C12—C8—C9—C10	178.77 (10)	C13—N2—C12—C8	−177.26 (10)
C2—C1—C9—C8	−177.99 (11)	C7—C8—C12—O2	1.05 (18)
C11—C1—C9—C8	3.07 (17)	C9—C8—C12—O2	−178.36 (11)
C2—C1—C9—C10	1.98 (17)	C7—C8—C12—N2	−179.32 (10)
C11—C1—C9—C10	−176.96 (10)	C9—C8—C12—N2	1.26 (16)
C6—C5—C10—C9	0.20 (18)	C12—N2—C13—C14	85.98 (13)
C6—C5—C10—C4	−178.62 (11)	C11—N2—C13—C14	−88.36 (13)
C8—C9—C10—C5	0.20 (17)	N2—C13—C14—C15	−179.86 (10)
C1—C9—C10—C5	−179.77 (10)	C13—C14—C15—C16	−179.09 (10)
C8—C9—C10—C4	179.06 (10)	C4—N1—C17—C18	−176.79 (11)
C1—C9—C10—C4	−0.91 (17)	N1—C17—C18—C19	−178.96 (10)
N1—C4—C10—C5	−2.33 (18)	C17—C18—C19—C20	178.82 (10)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1^i	0.877 (18)	2.255 (18)	3.0744 (14)	155.4 (15)

Symmetry code: (i) x, −y+2, z+1/2.