P. Prince

Molecules for intramolecular recognition. Synthesis and structures of diaryl- and arylnaphthylethynes

Abstract While synthesizing models for intramolecular recognition, a simple and efficient method for forming terminal arylethynes was developed and palladium-catalyzed coupling chemistry of alkynes with either aryl iodides or aryl triflates was used to form crowded disubstituted alkynes.

Molecules for intramolecular recognition. 2. Synthesis and structures of dinaphthyl- and arylnaphthylethynes.

Three new tetrasubstituted diaryl alkynes have been prepared via palladium-catalyzed coupling of aromatic alkynes with aryl iodides. These molecules show strong absorption and fluorescence. Single crystal X-ray analysis reveals that the rings are on parallel planes.

1-Ethynyl-2,7-dimethoxynaphthalene: an example of hydrogen bonding between an ethynylic hydrogen and a methoxyl oxygen

C14H12O2, Mr = 212.3, triclinic, P1, a = 6.6160 (12), b = 11.359 (2), c = 16.217 (2) A, alpha = 80.640 (11), beta = 86.305 (13), gamma = 78.858 (12) degrees, V = 1179.2 (4) A3, Z = 4, D chi = 1.196 g cm-3, lambda(Cu K alpha) = 1.54184 A, mu = 6.01 cm-1, F(000) = 448, T = 295 K, R = 0.039 for 3488 observations (of 4844 unique data). The crystal consists of two independent molecules related by a C--H...O contact. The donor is the ethynylic H on one molecule, and the acceptor is the methoxyl O ortho to the ethynylic group on the other molecule. The = C--H...O bond length (C to O distance) is 3.260 (2) A and the angle at H is 164 (1) degrees. The naphthalene ring system of the two independent molecules shows an average deviation from planarity of 0.007 (2) and 0.008 (2) A with respective maximum deviations of 0.015 (1) and 0.014 (2) A.

1-Iodo-2-methoxy-7-naphthyl Acetate

The asymmetric unit of the title compound, C 13 H 11 IO 3 , contains two independent molecules. The naphthalene ring systems of the molecules have average deviations from planarity of 0.029(13) and 0.017(9) A with maximum deviations of 0.042(11) and 0.034(9) A, respectively. The methyl parts of the methoxy groups are anti to the neighboring α-C atoms and are nearly coplanar with the rings, with C-C-O-C torsion angles of -8.1(15) and -3.7 (10)° in the two molecules. The dihedral angles between the naphthalene ring system and the acetate group in each molecule are 109.9(2) and 114.6 (2)°.

2-Acetoxy-7-methoxynaphthalene

The naphthalene ring system of the title compound (7-methoxy-2-naphthyl acetate, C 13 H 12 O 3 ) is slightly non-planar, the average deviation being 0.025 (1) A, with a maximum deviation of 0.041 (1) A for the C atom carrying the methoxy group. The methoxy group has the methyl syn to the neighboring α-C atom, and is nearly coplanar with the ring, with a C-C-O-C torsion angle of -5,2 (2) o . The dihedral angle between the naphthalene ring system and the acetoxyl group is 115.8 (1) o , with a C-C-O-C torsion angle of 67.2 (2) o

1-acetyl-7-methoxy-2-naphthol

C 13 H 12 O 3 , Pna2 1 , a=7.4946, b=13.437, c=10.8630 A, R=0.043. The average deviation from planarity is 0.047 A.

1-(1-Chlorovinyl)-2,7-dimethoxynaphthalene

C14H13ClO2, Mr = 248.71, monoclinic, P21/n, a = 11.291 (1), b = 7.343 (1), c = 15.223 (2) A, beta = 90.899 (8) degrees, V = 1262.0 (5) A3, Z = 4, Dx = 1.309 g cm-3, lambda(CU K alpha) = 1.54184 A, mu = 26.0 cm-1, F(000) = 520, T = 299 K, R = 0.041 for 2405 observations (of 2516 unique data). The average deviation from planarity is 0.019 (2) A with a maximum of 0.035 (1) A for the fused rings. The dihedral angle between the naphthalene system and the chlorovinyl group is 101.93 (4) degrees. The methoxy group ortho to the chlorovinyl adopts a conformation with the methyl group anti to the neighboring alpha carbon of the ring, with a C-C-O-C torsion angle of -175.6 (2) degrees. The other methoxy group has the methyl syn to the neighboring alpha carbon, with a C-C-O-C torsion angle of 1.9 (3) degrees.

3-(2-Methoxyphenyl)-1H-2-benzopyran-1-one

C16H12O3, Mr = 252.3, orthorhombic, Pna21, a = 6.633 (3), b = 13.367 (2), c = 14.056 (2) A, V = 1246.3 (9) A3, Z = 4, Dx = 1.344 g cm-3, lambda (Cu K alpha) = 1.54184 A, mu = 7.17 cm-1, F(000) = 528, T = 296 K, R = 0.027 for 2337 observations (of 2508 unique date). The average deviation from planarity is 0.013 (1) A with a maximum of 0.028 (1) A for the fused-rings system, and 0.003 (1) A with a maximum of 0.005 (1) A for the methoxyphenyl ring. The dihedral angle between the two systems is 4.7 (3) degrees. The methoxyphenyl ring is pushed away from the vinyl proton and towards the endocyclic O atom; the bond angles are 130.13 (9) and 110.13 (8) degrees, respectively.

1-Acetyl-2,7-dimethoxynaphthalene

C14H14O3, Mr = 230.3, monoclinic, P2(1)/c, a = 8.8107 (9), b = 18.372 (3), c = 7.7512 (11) A, beta = 98.49 (1) degrees, V = 1240.9 (5) A3, Z = 4, Dx = 1.232 g cm-3, lambda(Mo K alpha) = 0.71073 A, mu = 0.80 cm-1, F(000) = 488, T = 293 K, R = 0.047 for 1909 observations (of 2848 unique data). The average deviation from planarity is 0.017 (2) A with a maximum of 0.0285 (15) A for the fused rings. The dihedral angle between the naphthalene system and the acetyl group is 117.91 (6) degrees. The methoxyl group ortho to the acetyl adopts a conformation with the methyl group anti to the neighboring alpha-carbon of the ring, with a C-C-O-C torsion angle of -178.7 (2) degrees. The other methoxyl group has the methyl syn to the neighboring alpha-carbon, with a C-C-O-C torsion angle of -1.3 (3) degrees.

Methyl 3,4-dihydro-1-oxo-2(1H)-naphthylidenehydroxyacetate

C13H12O4, Mr = 232.2, monoclinic, P2(1)/c, a = 8.499 (2), b = 13.798 (4), c = 9.652 (2) A, beta = 98.25 (2) degrees, V = 1120.1 (9) A3, Z = 4, Dx = 1.377 g cm-3, lambda(Cu K alpha) = 1.54184 A, mu = 8.12 cm-1, F(000) = 488, T = 295 K, R = 0.042 for 1916 observations (of 2296 unique data). The molecule contains an enol subunit, the hydroxy group of which forms an intramolecular hydrogen bond to the cyclic carbonyl group, with an O...O distance of 2.4782 (14) A and an O-H...O angle of 143 (3) degrees. The refined position of the hydrogen atom is 1.16 (4) A from the hydroxy oxygen and 1.44 (4) A from the carbonyl oxygen, and the isotropic thermal parameter is large; B = 13 (1) A2. The enol C = C bond distance is 1.371 (1) A and its C-OH distance is 1.312 (1) A.