10-Methyl-isoalloxazine 5-oxide from synchrotron powder diffraction data.

THE TITLE COMPOUND [SYSTEMATIC NAME: 10-methyl-benzo[g]pteridine-2,4(3H,10H)-dione 5-oxide], C(11)H(8)N(4)O(3), consists of a large rigid isoalloxazine group which is approximately planar (r.m.s. deviation = 0.037 Å). In the crystal, inter-molecular N-H⋯O hydrogen bonds link the mol-ecules into centrosymmetric dimers. Dimers related by translation along the c axis form stacks through π-π inter-actions [centroid-centroid distances = 3.560 (5) and 3.542 (5) Å]. Weak inter-molecular C-H⋯O inter-actions further consolidate the crystal packing.

Related literature

For the preparation of the title compound, see: Yoneda et al. (1976 ▶). For background to flavins, see: Massey (2000 ▶), Palfey & Massey (1998 ▶); Müller (1991 ▶). For a description of the Cambridge Structural Database, see: Allen (2002 ▶). For the crystal structures of similar compounds, see: Wang & Fritchie (1973 ▶); Farrán et al. (2007 ▶).

Experimental

Crystal data

C11H8N4O3

M = 244.21

Monoclinic,

a = 13.8774 (6) Å

b = 14.5321 (4) Å

c = 4.9305 (2) Å

β = 90.830 (3)°

V = 994.22 (5) Å3

Z = 4

Synchrotron radiation

λ = 0.8856 Å

μ = 0.20 mm−1

T = 293 K

cylinder, 20 × 1 mm

Data collection

ESRF Grenoble, BM20 diffractometer

Specimen mounting: capilary

Data collection mode: transmission

Scan method: step

2θmin = 4.0°, 2θmax = 36.5°, 2θstep = 0.01°

Refinement

R p = 0.042

R wp = 0.056

R exp = 0.021

R Bragg = 0.06

R(F 2) = 0.060

χ2 = 7.129

3251 data points

73 parameters

57 restraints

H-atom parameters not refined

Data collection: ESRF SPEC (Certified Scientific Software, 2003 ▶); cell refinement: GSAS (Larson & Von Dreele, 1994 ▶); data reduction: CRYSFIRE (Shirley, 2000 ▶); program(s) used to solve structure: FOX (Favre-Nicolin & Černý, 2002 ▶); program(s) used to refine structure: GSAS; molecular graphics: Mercury (Macrae et al., 2006 ▶) and PLATON (Spek, 2009 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810048932/cv5002sup1.cif

Rietveld powder data: contains datablocks I. DOI: 10.1107/S1600536810048932/cv5002Isup2.rtv

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C11H8N4O3	Z = 4
Mr = 244.21	F(000) = 504
Monoclinic, P21/a	Dx = 1.633 Mg m−3
Hall symbol: -P 2yab	Synchrotron radiation, λ = 0.8856 Å
a = 13.8774 (6) Å	µ = 0.20 mm−1
b = 14.5321 (4) Å	T = 293 K
c = 4.9305 (2) Å	yellow
β = 90.830 (3)°	cylinder, 20 × 1 mm
V = 994.22 (5) Å3

ESRF Grenoble, BM20 diffractometer	Data collection mode: transmission
Radiation source: synchrotron	Scan method: step
Specimen mounting: capilary	2θmin = 4.0°, 2θmax = 36.5°, 2θstep = 0.01°

Least-squares matrix: full	73 parameters
Rp = 0.042	57 restraints
Rwp = 0.056	0 constraints
Rexp = 0.021	Hydrogen site location: inferred from neighbouring sites
RBragg = 0.06	H-atom parameters not refined
R(F2) = 0.06000	Weighting scheme based on measured s.u.'s
χ2 = 7.129	(Δ/σ)max = 0.02
3251 data points	Background function: GSAS Background function number 1 with 20 terms. Shifted Chebyshev function of 1st kind 1: 1199.79 2: -234.522 3: -315.536 4: 152.956 5: 123.532 6: -246.657 7: 116.810 8: 83.9272 9: -107.809 10: -12.4938 11: 79.2500 12: -25.2804 13: -27.8174 14: 13.6120 15: 6.03858 16: -3.86487 17: 2.09281 18: 9.92947 19: -18.6000 20: 1.36657
Excluded region(s): none	Preferred orientation correction: March-Dollase AXIS 1 Ratio= 0.89956 h= 0.000 k= 0.000 l= 1.000 Prefered orientation correction range: Min= 0.85318, Max= 1.37377
Profile function: CW Profile function number 4 with 21 terms Pseudovoigt profile coefficients as parameterized in P. Thompson, D.E. Cox & J.B. Hastings (1987). J. Appl. Cryst.,20,79-83. Asymmetry correction of L.W. Finger, D.E. Cox & A. P. Jephcoat (1994). J. Appl. Cryst.,27,892-900. Microstrain broadening by P.W. Stephens, (1999). J. Appl. Cryst.,32,281-289. #1(GU) = 118.875 #2(GV) = 80.014 #3(GW) = 0.010 #4(GP) = 0.000 #5(LX) = 1.385 #6(ptec) = 0.00 #7(trns) = 0.00 #8(shft) = 0.0000 #9(sfec) = 0.00 #10(S/L) = 0.0005 #11(H/L) = 0.0142 #12(eta) = 0.0000 #13(S400 ) = 1.7E-01 #14(S040 ) = 1.8E-02 #15(S004 ) = 6.2E-01 #16(S220 ) = -4.6E-02 #17(S202 ) = 3.4E-01 #18(S022 ) = 1.6E-01 #19(S301 ) = -5.6E-01 #20(S103 ) = 7.9E-01 #21(S121 ) = 7.0E-02 Peak tails are ignored where the intensity is below 0.0001 times the peak Aniso. broadening axis 0.0 0.0 1.0

	x	y	z	Uiso*/Ueq
N1	0.0773 (7)	0.1443 (5)	1.0053 (18)	0.036 (6)*
C2	0.0483 (8)	0.0827 (7)	1.194 (3)	0.075 (8)*
N3	0.0977 (7)	−0.0028 (6)	1.2303 (19)	0.068 (6)*
C4	0.1784 (5)	−0.0297 (5)	1.0946 (14)	0.028 (8)*
C4a	0.2075 (5)	0.0367 (5)	0.8768 (14)	0.049 (7)*
N5	0.2843 (7)	0.0175 (6)	0.725 (2)	0.120 (8)*
C5a	0.3110 (6)	0.0833 (6)	0.5319 (18)	0.077 (9)*
C6	0.3917 (7)	0.0645 (6)	0.365 (2)	0.037 (7)*
C7	0.4210 (6)	0.1290 (8)	0.180 (2)	0.052 (7)*
C8	0.3703 (8)	0.2112 (7)	0.1520 (18)	0.059 (8)*
C9	0.2917 (7)	0.2332 (6)	0.311 (2)	0.054 (8)*
C9a	0.2610 (6)	0.1684 (6)	0.5019 (18)	0.045 (9)*
N10	0.1787 (7)	0.1824 (7)	0.6664 (19)	0.078 (7)*
C10a	0.1522 (5)	0.1216 (5)	0.8572 (14)	0.046 (8)*
O11	−0.0238 (7)	0.1000 (7)	1.338 (2)	0.063 (5)*
O12	0.2230 (7)	−0.1014 (5)	1.1524 (17)	0.037 (4)*
O13	0.3291 (8)	−0.0597 (7)	0.748 (2)	0.100 (5)*
C14	0.1211 (10)	0.2660 (9)	0.619 (3)	0.095 (9)*
H1N3	0.0746	−0.0405	1.3466	0.0804*
H1C6	0.425	0.0076	0.3816	0.0456*
H1C7	0.4758	0.1173	0.0718	0.0612*
H1C8	0.3906	0.254	0.0188	0.0708*
H1C9	0.2597	0.2905	0.2901	0.0636*
H1C14	0.1488	0.3013	0.479	0.114*
H2C14	0.119	0.3013	0.781	0.114*
H3C14	0.057	0.249	0.567	0.114*

O11—C2	1.261 (16)	N10—C9a	1.425 (13)
C4—C4a	1.503 (10)	N3—C2	1.429 (14)
O12—C4	1.243 (11)	N3—C4	1.370 (12)
C5a—C9a	1.425 (12)	N5—C5a	1.403 (13)
O13—N5	1.287 (14)	N5—C4a	1.341 (12)
C5a—C6	1.426 (13)	C10a—C4a	1.455 (10)
N1—C10a	1.321 (12)	C14—H1C14	0.9500
C6—C7	1.374 (14)	C14—H2C14	0.9500
N1—C2	1.356 (15)	C14—H3C14	0.9500
C7—C8	1.392 (15)	C6—H1C6	0.9500
N10—C10a	1.346 (12)	C7—H1C7	0.9500
C8—C9	1.390 (14)	N3—H1N3	0.8600
N10—C14	1.471 (17)	C8—H1C8	0.9500
C9—C9a	1.402 (13)	C9—H1C9	0.9500
Cg1···Cg2i	3.56 (1)	Cg1···Cg3i	3.54 (1)
C2—N1—C10A	117.3 (8)	C8—C9—C9A	118.2 (8)
C2—N3—C4	125.5 (9)	N10—C9A—C5A	117.3 (8)
O13—N5—C4A	121.3 (9)	N10—C9A—C9	122.7 (8)
O13—N5—C5A	121.5 (9)	C5A—C9A—C9	120.0 (8)
C4A—N5—C5A	117.2 (8)	N1—C10A—N10	116.6 (8)
C9A—N10—C10A	122.3 (9)	N1—C10A—C4A	126.4 (7)
C9A—N10—C14	117.8 (9)	N10—C10A—C4A	117.0 (7)
C10A—N10—C14	120.0 (9)	C2—N3—H1N3	117
O11—C2—N1	120.0 (10)	C4—N3—H1N3	117
O11—C2—N3	119.1 (11)	C5A—C6—H1C6	120
N1—C2—N3	120.9 (10)	C7—C6—H1C6	120
O12—C4—N3	122.4 (8)	C6—C7—H1C7	120
O12—C4—C4A	124.3 (7)	C8—C7—H1C7	120
N3—C4—C4A	113.3 (7)	C7—C8—H1C8	118
N5—C4A—C4	119.3 (7)	C9—C8—H1C8	119
N5—C4A—C10A	124.2 (7)	C8—C9—H1C9	121
C4—C4A—C10A	116.4 (6)	C9A—C9—H1C9	121
N5—C5A—C6	118.6 (8)	N10—C14—H1C14	110
N5—C5A—C9A	121.9 (8)	N10—C14—H2C14	110
C6—C5A—C9A	119.5 (8)	N10—C14—H3C14	109
C5A—C6—C7	119.7 (8)	H1C14—C14—H2C14	110
C6—C7—C8	119.8 (9)	H1C14—C14—H3C14	109
C7—C8—C9	122.8 (9)

D—H···A	D—H	H···A	D···A	D—H···A
N3—H1N3···O11ii	0.86	1.92	2.764 (14)	166
C14—H2C14···O12iii	0.95	2.63	3.097 (16)	111
C14—H1C14···O13iv	0.95	2.33	3.194 (17)	151

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N3—H1N3⋯O11i	0.86	1.92	2.764 (14)	166
C14—H2C14⋯O12ii	0.95	2.63	3.097 (16)	111
C14—H1C14⋯O13iii	0.95	2.33	3.194 (17)	151

Symmetry codes: (i) ; (ii) ; (iii) .