5,6-Dimeth­oxy-2-methylisoindole-1,3-dione

The molecule of the title compound, C₁₁H₁₁NO₄ (alternative name: 4,5-dimeth­oxy-N-methyl­phthalimide), a highly fluorescent phthal­imide, is essentially planar. In the crystal structure, pairs of mol­ecules form a π-stacked head-to-tail dimer with a remarkably short inter­planar distance of 3.34 (2) Å.

Key indicators

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.052
• wR factor = 0.124
• Data-to-parameter ratio = 11.0

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT222_ALERT_3_B Large Non-Solvent    H     Ueq(max)/Ueq(min) ...       4.90 Ratio

Alert level C
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......       0.96

   0 ALERT level A = In general: serious problem
   1 ALERT level B = Potentially serious problem
   1 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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Computing details

Data collection: COLLECT (Nonius, 1999); cell refinement: DENZO (Otwinowski & Minor, 1997); data reduction: DENZO; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SCHAKAL 99 (Keller & Pierrard, 1999); software used to prepare material for publication: SHELXL97, PLATON (Spek, 2003) and enCIFer (Allen et al., 2004).

5,6-Dimethoxy-2-methylisoindole-1,3-dione

Crystal data

C11H11NO4	Z = 2
Mr = 221.21	F(000) = 232
Triclinic, P1	Dx = 1.488 Mg m^−3
Hall symbol: -P 1	Melting point: 538 K
a = 7.3142 (5) Å	Mo Kα radiation, λ = 0.71073 Å
b = 8.3134 (11) Å	Cell parameters from 2663 reflections
c = 9.7468 (16) Å	θ = 2.3–27.0°
α = 96.266 (4)°	µ = 0.12 mm^−1
β = 108.402 (6)°	T = 100 K
γ = 114.087 (6)°	Prism, colourless
V = 493.64 (11) Å^3	0.2 × 0.13 × 0.1 mm

Data collection

Nonius KappaCCD area-detector diffractometer	1404 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.028
Graphite monochromator	θmax = 27.0°, θmin = 2.3°
φ and ω scans	h = −9→9
2663 measured reflections	k = −10→7
2073 independent reflections	l = −12→12

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)] = 0.052	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.124	All H-atom parameters refined
S = 1.07	w = 1/[σ^2(Fo^2) + (0.0457P)^2 + 0.1764P] where P = (Fo^2 + 2Fc^2)/3
2073 reflections	(Δ/σ)max = 0.001
189 parameters	Δρmax = 0.26 e Å^−3
0 restraints	Δρmin = −0.25 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	0.3600 (3)	0.7240 (2)	0.65825 (19)	0.0220 (4)
O2	0.6696 (3)	1.3477 (2)	0.83423 (19)	0.0207 (4)
O3	1.1094 (2)	1.1852 (2)	1.33103 (18)	0.0179 (4)
O4	0.9420 (2)	0.8394 (2)	1.23234 (18)	0.0179 (4)
N1	0.4832 (3)	1.0381 (3)	0.7118 (2)	0.0163 (5)
C1	0.4784 (4)	0.8761 (3)	0.7434 (3)	0.0163 (5)
C2	0.6352 (4)	1.1911 (3)	0.8328 (3)	0.0148 (5)
C3	0.7377 (3)	1.1215 (3)	0.9533 (3)	0.0139 (5)
C4	0.8961 (4)	1.2165 (3)	1.0968 (3)	0.0143 (5)
C5	0.9580 (3)	1.1142 (3)	1.1872 (3)	0.0151 (5)
C6	0.8639 (4)	0.9214 (3)	1.1325 (3)	0.0141 (5)
C7	0.7056 (4)	0.8294 (3)	0.9877 (3)	0.0141 (5)
C8	0.6437 (3)	0.9333 (3)	0.8992 (3)	0.0137 (5)
C9	1.1924 (4)	1.3765 (3)	1.4001 (3)	0.0232 (6)
C10	0.8318 (4)	0.6425 (3)	1.1922 (3)	0.0227 (6)
C11	0.3379 (4)	1.0457 (4)	0.5728 (3)	0.0212 (6)
H4	0.964 (3)	1.347 (3)	1.128 (2)	0.010 (6)*
H7	0.637 (3)	0.699 (3)	0.946 (3)	0.010 (6)*
H9A	1.298 (4)	1.403 (3)	1.507 (3)	0.031 (7)*
H9B	1.274 (4)	1.455 (3)	1.344 (3)	0.019 (6)*
H9C	1.071 (4)	1.405 (3)	1.394 (3)	0.029 (7)*
H10A	0.839 (4)	0.591 (3)	1.097 (3)	0.028 (7)*
H10B	0.670 (5)	0.599 (4)	1.179 (3)	0.042 (8)*
H10C	0.905 (4)	0.610 (3)	1.283 (3)	0.034 (8)*
H11A	0.263 (4)	0.928 (4)	0.495 (3)	0.025 (7)*
H11B	0.428 (4)	1.144 (4)	0.538 (3)	0.036 (8)*
H11C	0.227 (5)	1.074 (4)	0.595 (3)	0.049 (9)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0218 (9)	0.0191 (10)	0.0162 (10)	0.0071 (8)	0.0021 (8)	−0.0009 (8)
O2	0.0228 (9)	0.0194 (10)	0.0210 (10)	0.0113 (8)	0.0065 (8)	0.0097 (8)
O3	0.0208 (9)	0.0147 (9)	0.0114 (9)	0.0079 (7)	−0.0008 (7)	0.0023 (7)
O4	0.0221 (9)	0.0150 (9)	0.0159 (9)	0.0098 (7)	0.0044 (7)	0.0065 (7)
N1	0.0158 (10)	0.0203 (11)	0.0115 (11)	0.0095 (9)	0.0023 (9)	0.0050 (9)
C1	0.0148 (12)	0.0218 (14)	0.0159 (13)	0.0104 (11)	0.0078 (11)	0.0057 (11)
C2	0.0126 (11)	0.0187 (13)	0.0149 (13)	0.0076 (10)	0.0068 (10)	0.0066 (10)
C3	0.0136 (12)	0.0189 (13)	0.0119 (13)	0.0097 (10)	0.0051 (10)	0.0062 (10)
C4	0.0157 (12)	0.0128 (13)	0.0144 (13)	0.0067 (10)	0.0059 (11)	0.0040 (10)
C5	0.0129 (12)	0.0180 (13)	0.0127 (13)	0.0069 (10)	0.0039 (10)	0.0024 (10)
C6	0.0159 (11)	0.0180 (13)	0.0136 (13)	0.0106 (10)	0.0068 (11)	0.0087 (10)
C7	0.0170 (12)	0.0116 (12)	0.0144 (13)	0.0070 (10)	0.0069 (11)	0.0032 (10)
C8	0.0128 (11)	0.0169 (13)	0.0118 (13)	0.0074 (10)	0.0052 (10)	0.0030 (10)
C9	0.0263 (15)	0.0134 (14)	0.0185 (15)	0.0061 (11)	0.0007 (13)	0.0007 (11)
C10	0.0300 (15)	0.0159 (14)	0.0222 (16)	0.0119 (12)	0.0075 (13)	0.0088 (12)
C11	0.0216 (13)	0.0317 (16)	0.0108 (14)	0.0158 (13)	0.0015 (11)	0.0088 (12)

Geometric parameters (Å, º)

O1—C1	1.209 (3)	C4—H4	0.95 (2)
O2—C2	1.218 (3)	C5—C6	1.417 (3)
O3—C5	1.358 (3)	C6—C7	1.388 (3)
O3—C9	1.439 (3)	C7—C8	1.389 (3)
O4—C6	1.360 (3)	C7—H7	0.96 (2)
O4—C10	1.437 (3)	C9—H9A	1.01 (3)
N1—C2	1.391 (3)	C9—H9B	1.03 (3)
N1—C1	1.403 (3)	C9—H9C	0.99 (2)
N1—C11	1.461 (3)	C10—H10A	1.01 (3)
C1—C8	1.485 (3)	C10—H10B	1.04 (3)
C2—C3	1.491 (3)	C10—H10C	1.00 (3)
C3—C4	1.382 (3)	C11—H11A	0.99 (3)
C3—C8	1.383 (3)	C11—H11B	0.99 (3)
C4—C5	1.390 (3)	C11—H11C	1.01 (3)
C5—O3—C9	117.38 (18)	C6—C7—H7	124.0 (13)
C6—O4—C10	117.26 (19)	C8—C7—H7	118.5 (13)
C2—N1—C1	111.78 (19)	C3—C8—C7	121.1 (2)
C2—N1—C11	123.6 (2)	C3—C8—C1	108.53 (19)
C1—N1—C11	124.5 (2)	C7—C8—C1	130.4 (2)
O1—C1—N1	125.3 (2)	O3—C9—H9A	105.9 (15)
O1—C1—C8	129.1 (2)	O3—C9—H9B	110.2 (13)
N1—C1—C8	105.66 (19)	H9A—C9—H9B	109 (2)
O2—C2—N1	124.6 (2)	O3—C9—H9C	110.6 (15)
O2—C2—C3	129.2 (2)	H9A—C9—H9C	114 (2)
N1—C2—C3	106.12 (19)	H9B—C9—H9C	106 (2)
C4—C3—C8	122.5 (2)	O4—C10—H10A	110.1 (15)
C4—C3—C2	129.6 (2)	O4—C10—H10B	108.2 (15)
C8—C3—C2	107.9 (2)	H10A—C10—H10B	111 (2)
C3—C4—C5	117.1 (2)	O4—C10—H10C	104.9 (15)
C3—C4—H4	119.9 (13)	H10A—C10—H10C	115 (2)
C5—C4—H4	122.9 (13)	H10B—C10—H10C	108 (2)
O3—C5—C4	124.7 (2)	N1—C11—H11A	110.5 (15)
O3—C5—C6	114.38 (19)	N1—C11—H11B	107.7 (16)
C4—C5—C6	120.9 (2)	H11A—C11—H11B	110 (2)
O4—C6—C7	124.6 (2)	N1—C11—H11C	108.4 (17)
O4—C6—C5	114.6 (2)	H11A—C11—H11C	110 (2)
C7—C6—C5	120.9 (2)	H11B—C11—H11C	111 (2)
C6—C7—C8	117.6 (2)