S. Natarajan

Structure of 3-(2-benzimidazolyl)-7-(diethylamino)coumarin

C20H19N302, M r = 33339, triclinic, P1, a = 10.350(7), b=12990(5), c=6753(3) A, a= 100.89(4), /3 = 10623(4), 3=9884(5) °, V 8352 (8) A 3, Z = 2, O m = 1345, Dx = 1325 g cm- , A(Mo Ka) = 0.71069 A, /x = 0.817 cm-1, F(000) = 352, T=296K. Final R value is 0.071 for 1626 observed reflections. The coumarin and benz- imidazole ring systems are planar. Intramolecular hydrogen bonds of N--H...O type exist. The crystal structure is stabilized by van der Waals forces. anisotropic thermal parameters for non-H and iso- tropic for H atoms, final R = 0.071, wR = 0-067, S = 1.65, w = l9825/(~r2(tFo() 000004Fo2). The R value is high due to poor crystal quality, (A/O)max = 0.014, final difference map featureless with max. and min. peak heights 0.35 and -0.27 e/~-3; no correc- tion for secondary extinction, atomic scattering fac- tors for all atoms as in SHELX76 (Sheldrick, 1976), geometrical calculations using PARST (Nardelli, 1983). Introduction. Some aminocoumarin derivatives, in weakly polar solvents and under laser excitation, give an anomalous band due to the TICT (twisted intra- molecular charge transfer) state. Solute-solvent interactions aid the stability of this state (Masi- lamani, Sastikumar, Natarajan & Natarajan, 1987). The title compound (also called coumarin 7) is found to give laser action at 525 nm in the vapour phase (Logunov, Startsev & Stoilov, 1981), and in a mix- ture of water and N,N-dipropylacetamide (Tuccio, Drexhage & Reynolds, 1973). The possibility of occurrence and stability of the TICT state for the title compound is discussed on a structural basis.

1,2,3,3,8-Pentamethyl-5-trifluoromethyl-2,3-dihydro-1H-pyrrolo[2,3-g]quinolin-7(8H)-one

C 17 H 19 F 3 N 2 O cristalline dans P2 1 /a avec a=10,694, b=12,216, c=12,356 A, β=94,24°, Z=4; affinement jusqua R=0,044. Le cycle quinolone est plan et le cycle dihydropyrrole adopte une conformation enveloppe avec un angle de torsion absolu moyen de 25°

Structure of 7-ethylamino-4,6-dimethylcoumarin

C 13 H 15 NO 2 cristallise dans P2 1 /c avec a=7,343, b=7,800 et c=19,589 A, β=91,45 o , Z=4; affinement jusqua R= 0,051. La moitie coumarine est plane et le groupement ethylamino est coplanaire avec le systeme cyclique. La structure du cristal est stabilisee par des liaisons hydrogene intermoleculaires N―H...O entre les molecules apparentees par glissement avec une distance N...O de 3,119 A et un angle N―H...O de 173 o

7-Hydroxy-4-coumarinacetic acid monohydrate

C 11 H 8 O 5 .H 2 O cristallise dans P2 1 avec a=4,394, b=10,367, c=11,657 A, β=95,13°, Z=2; affinement jusqua R=0,039. La partie coumarine est plane et le plan du groupement acide acetique fait un angle de 77,35° avec elle. La structure cristalline est stabilisee par des liaisons hydrogene etendues O−H...O impliquant la molecule deau et les groupements hydroxy, cetone et acide de la partie coumarine

Structure of 7-ethylamino-6-methyl-4-trifluoromethylcoumarin

C13H12F3NO2, M(r) = 271.2, triclinic, P1BAR, a = 5.029 (2), b = 7.479 (2), c = 17.073 (5) angstrom, alpha = 97.98 (2), beta = 95.54 (3), gamma = 103.62 (3)-degrees, V = 612.4 (4) angstrom 3, Z = 2, D(m) = 1.463, D(x) = 1.471 g cm-3, lambda(Mo K-alpha) = 0.71069 angstrom, mu = 1.23 cm-1, F(000) = 280, T = 298 K, final R value is 0.041 for 2047 observed reflections with F(omicron) greater-than-or-equal-to 6-sigma(F(omicron)). The N-C(sp2) bond length is 1.356 (2) angstrom. The N and C atoms of the ethylamino group deviate by < 0.15 angstrom from the plane of the aromatic ring. Short intramolecular contacts, C(3)...F(17) 2.668 (3) angstrom [H(3)...F(17) 2.39 (2) angstrom, C(3)-H(C3)...F(17) 98 (1)-degrees], C(5)...F(18) 3.074 (3) and C(5)...F(19) 3.077 (3) angstrom exist in the structure. The crystal structure is stabilized by intermolecular N-H...O hydrogen bonds with N(12)-H(N12) 0.79 (3), H(N12)...O(11) 2.36 (3), N(12)...O(11) (x - 1, y + 1, z) 3.105 (3) angstrom and N(12)-H(N12)...O(11) 155 (2)-degrees.

2,3,6,7-tetrahydro-9-methyl-1H,5H-quinolizino[9,1-gh]coumarin

C 16 H 17 NO 2 cristallise dans P2 1 /a avec a=8,253, b=15,660, c=10,112 A, β=95,82°, Z=4; affinement jusqua R=0,065. La moitie coumarine est plane et les deux cycles piperidine adoptent des conformations demi-chaise aplatie

Ethyl 7-hydroxy-4-coumarinacetate

C 13 H 12 O 5 cristallise dans P2 1 avec a=4,698, b=10,277, c=12,009A, β=99,58°, Z=2; affinement jsuqua R=0,037. La partie coumarine est plane et le plan du groupement acetate dethyle fait un angle de 88,1° avec elle. La structure cristalline est stabilisee par des liaisons hydrogene O−H...O

3-(2-hydroxy-5-methylbenzyl)-6-methylcoumarin

C 18 H 16 O 3 cristallise dans P2 1 /a avec a=7,324, b=28,326, c=7,304 A, β=107,31 o , Z=4; affinement jusqua R=0,058. Le plan du cycle phenyl forme un angle de 113,2 o avec le plan de la partie coumarine