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1.  2,2′-[Imidazolidine-1,3-diylbis(methyl­ene)]diphenol 
In the title mol­ecule, C17H20N2O2, the imidazolidine ring adopts a twist conformation. The mean plane through the five atoms of the imidazolidine ring makes dihedral angles of 70.18 (4) and 74.14 (4)° with the planes of the two aromatic rings. The dihedral angle between the benzene rings is 53.11 (5)°. Both phenol –OH groups form intra­molecular hydrogen bonds to the N atoms, with graph-set motif S(6). In the crystal, pairs of O—H⋯O hydrogen bonds link the mol­ecules into dimers with R 4 4(18) ring motifs. The crystal packing is further stabilized by C—H⋯O and weak C—H⋯π inter­actions.
doi:10.1107/S1600536811053748
PMCID: PMC3254510  PMID: 22259455
2.  4,4′-Dimethyl-2,2′-[imidazolidine-1,3-diylbis(methyl­ene)]diphenol 
The imidazolidine ring in the title compound, C19H24N2O2, adopts a twist conformation and its mean plane (r.m.s. deviation = 0.19 Å) makes dihedral angles of 72.38 (9) and 71.64 (9)° with the two pendant aromatic rings. The dihedral angle between the phenyl rings is 55.94 (8)°. The mol­ecular structure shows the presence of two intra­molecular O—H⋯N hydrogen bonds between the phenolic hydroxyl groups and N atoms with graph-set motif S(6). In the crystal, C—H⋯O hydrogen bonds lead to the formation of chains along the b-axis direction.
doi:10.1107/S1600536812042808
PMCID: PMC3515265  PMID: 23284485
3.  4,4′-Dichloro-2,2′-[imidazolidine-1,3-diylbis(methylene)]diphenol 
The imidazolidine ring in the title compound, C17H18Cl2N2O2, adopts a twist conformation. The observed conformation is stabilized by two intra­molecular O—H⋯N hydrogen bonds, with both N atoms acting as hydrogen-bond acceptors. The phenyl substituents are aligned at 70.0 (1) and 76.6 (1)° with respect to the best plane through the five atoms of the imidazolidine ring. Weak inter­molecular C—H⋯O inter­actions stabilize the crystal packing.
doi:10.1107/S1600536811035677
PMCID: PMC3201546  PMID: 22065817
4.  A second tricilinc polymorph of 6,6′-dieth­oxy-2,2′-[propane-1,2-diylbis(nitrilo­methyl­idyne)]diphenol 
The title Schiff base compound, C21H26N2O4, is a second triclinic polymorph of a previously reported room-temperature structure [Jia (2009 ▶). Acta Cryst. E65, o646]. Strong intra­molecular O—H⋯N hydrogen bonds generate S(6) ring motifs. Inter­molecular C—H⋯O inter­actions link neighbouring mol­ecules into dimers with an R 2 2(16) ring motif. The mean planes of the two benzene rings are almost perpendicular to each other, making a dihedral angle of 88.24 (5)°. An inter­esting feature of the crystal structure is the intermolecular short C⋯O [3.1878 (13) Å] contact which is shorter than the sum of the van der Waals radii of the relevant atoms. The crystal structure is further stabilized by inter­molecular C—H⋯π and π–π inter­actions [centroid–centroid distance = 3.7414 (6) Å]. The structure has a stereogenic centre but the space group is centrosymmetric, so the mol­ecule exists as a racemate.
doi:10.1107/S1600536809008137
PMCID: PMC2968989  PMID: 21582458
5.  2,2′-{1,1′-[Pentane-1,5-diyl­bis(oxy­nitrilo)]­diethyl­idyne}diphenol 
In the title compound, C21H26N2O4, there is half a mol­ecule in the asymmetric unit with a crystallographic twofold rotation axis passing through the central C atom of the –CH=N—O—(CH2)5—O—N=CH– bridge. The dihedral angle formed by the two benzene rings is 80.85 (2)°. Strong intra­molecular O—H⋯N and C—H⋯O hydrogen bonds help to establish the molecular conformation. There are also weak inter­molecular π–π stacking inter­actions between neighbouring benzene rings [centroid–centroid separation = 3.502 (3) Å].
doi:10.1107/S160053680803136X
PMCID: PMC2959680  PMID: 21580925
6.  6,6′-Diethoxy-2,2′-[2,2-dimethylpropane-1,3-diylbis(nitrilomethylidyne)]diphenol 
In the crystal structure, the title Schiff base compound, C23H30N2O4, exhibits crystallographic twofold rotation symmetry. The imino group is coplanar with the aromatic ring with an N—C—C—C torsion angle of -179.72 (9)°. An intra­molecular O—H⋯N hydrogen bond forms a six-membered ring, producing an S(6) ring motif. The dihedral angle between symmetry related benzene rings is 28.05 (5)°. The eth­oxy group makes a C—O—C—C torsion angle of −7.20 (16)° with the benzene ring. The crystal structure is stabilized by inter­molecular C—H⋯π inter­actions.
doi:10.1107/S1600536809007557
PMCID: PMC2969095  PMID: 21582445
7.  6,6′-Dimeth­oxy-2,2′-[2,2-dimethyl­propane-1,3-diylbis(nitrilo­methyl­idyne)]diphenol 
The title Schiff base compound, C21H26N2O4, exhibits two crystallographically independent mol­ecules in the asymmetric unit with similar conformations. The imino groups are coplanar with the benzene rings; the maximum deviations of the N atoms from the planes comprising the benzene rings and the imino groups are −0.037 (4), 0.013 (4), −0.021 (5), and 0.008 (5) Å. The dihedral angles between the benzene rings in the two mol­ecules are 53.64 (17) and 51.93 (17)°. Strong intra­molecular O—H⋯N hydrogen bonds generate S(6) ring motifs. The N atoms are also in close proximity to the H atoms of the dimethyl­propane groups, with H⋯N distances between 2.54 and 2.75 Å. The crystal structure is further stabilized by weak inter­molecular C—H⋯O hydrogen bonds, weak inter­molecular C—H⋯π inter­actions and π–π contacts involving the imine C atom and two C atoms from the adjacent benzene rings.
doi:10.1107/S1600536808038002
PMCID: PMC2967940  PMID: 21581654
8.  4,4′-Di-tert-butyl-2,2′-[imidazolidine-1,3-diylbis(methyl­ene)]diphenol 
In the title compound, C25H36N2O2, the two tert-butyl-substituted benzene rings are inclined at an angle of 53.5 (3)° to one another. The imidazolidine ring has an envelope conformation with with one of the C atoms of the ethylene fragment as the flap. The structure displays two intra­molecular O—H⋯N hydrogen bonds that generate S(6) ring motifs. The crystal studied was a non-merohedral twin with a fractional contribution of 0.281(6) for the minor domain.
doi:10.1107/S1600536813017157
PMCID: PMC3770425  PMID: 24046710
9.  meso-4,4′-Difluoro-2,2′-{[(3aR,7aS)-2,3,3a,4,5,6,7,7a-octa­hydro-1H-1,3-benzimidazole-1,3-di­yl]bis­(methyl­ene)}diphenol 
In the crystal structure of the title compound, C21H24F2N2O2, there are two intra­molecular O—H⋯N hydrogen bonds involving the N atoms of the imidazolidine ring and the hy­droxy groups. The crystal studied was a meso compound obtained by the reaction of the aminal (2S,7R,11S,16R)-1,8,10,17-tetra­aza­penta­cyclo­[8.8.1.18,17.02,7.011,16]cosane with 4-fluoro­phenol. The imidazolidine ring has a twisted conformation with a CH—CH—N—CH2 torsion angle of 44.99 (14)° and, surprisingly, the lone pairs of the N atoms are disposed in a syn isomerism, making the title compound an exception to the typical ‘rabbit-ear effect’ in 1,2-diamines. In the crystal, molecules are linked via C—H⋯F hydrogen bonds, forming chains along the c-axis direction. These chains are linked via another C—H⋯F hydrogen bond, forming a three-dimensional network.
doi:10.1107/S1600536813000305
PMCID: PMC3569752  PMID: 23424498
10.  4,4′-Difluoro-2,2′-{[(3aRS,7aRS)-2,3,3a,4,5,6,7,7a-octa­hydro-1H-1,3-benzimidazole-1,3-di­yl]bis­(methyl­ene)]}diphenol 
In the crystal structure of the title compound, C21H24F2N2O2, the two N atoms of the imidazolidine moiety are linked to the hy­droxy groups by intra­molecular O—H⋯N hydrogen-bonding inter­actions. The crystal studied was a racemic mixture of RR and SS enatiomers. The cyclo­hexane ring adopts a chair conformation and the imidazolidine group to which it is fused has a twisted envelope conformation.
doi:10.1107/S1600536811019763
PMCID: PMC3120376  PMID: 21754901
11.  6,6′-Di-tert-butyl-4,4′-dimeth­oxy-2,2′-[1,3-diazinane-1,3-diylbis(methyl­ene)]diphenol 0.19-hydrate 
In the title hexa­hydro­pyrimidine derivative, C28H42N2O4·0.19H2O, the 1,3-diazinane ring has a chair conformation with a diequatorial substitution. The asymmetric unit contains one half-organic mol­ecule and a solvent water mol­ecule with occupany 0.095. The mol­ecule lies on a mirror plane perpendicular to [010] which passes through the C atoms at the 2- and 5-positions of the heterocyclic system. The partially occupied water mol­ecule is also located on this mirror plane. The dihedral angle between the planes of the aromatic rings is 17.71 (3)°. Two intra­molecular O—H⋯N hydrogen bonds with graph-set motif S(6) are present. No remarkable inter­molecular contacts exist in the crystal structure.
doi:10.1107/S1600536811053542
PMCID: PMC3254529  PMID: 22259475
12.  {3,3′,5,5′-Tetra­meth­oxy-2,2′-[ethane-1,2-diylbis(nitrilo­methyl­idyne)]diphenol­ato}­copper(II) 
In the title square-planar copper complex, [Cu(C20H22N2O6)], the Cu—N and Cu—O bond lengths are significantly longer than those of its isostructural nickel analog. The title structure is related to that of the corresponding monohydrate. There are significant differences in the conformations of the two complexes. While the monohydrate is mainly planar, in the title compound there is a slight twist in the two benzene rings at each end of the complex [dihedral angle = 13.14 (6)°]. All the atoms of the meth­oxy substitutents are in the plane of the ring to which they are attached (r.m.s. deviation = 0.0079 Å) except for one of the meth­oxy C atoms, which deviates slightly [0.309 (4) Å]. In the crystal, weak C—H⋯O inter­molecular inter­actions link the mol­ecules.
doi:10.1107/S1600536810017137
PMCID: PMC2979637  PMID: 21579299
13.  4,4′-Dimethoxy-2,2′-[1,1′-(propane-1,3-diyldinitrilo)diethylidyne]diphenol 
In the crystal structure, the title Schiff base compound, C21H26N2O4, has twofold rotation symmetry. The imino group is coplanar with the aromatic ring. An intra­molecular O—H⋯N hydrogen bond forms a six- membered ring, producing an S(6) ring motif. The two benzene rings are almost perpendicular to each other, making a dihedral angle of 85.00 (2)°. The meth­oxy group is approximately coplanar with the benzene ring, with a C—O—C—C torsion angle of 2.34 (12)°. Neighbouring mol­ecules are linked together by weak inter­molecular C—H⋯O hydrogen bonds and a C—H⋯π inter­action, forming a sheet parallel to the ab plane. The mol­ecules also adopt a zigzag arrangement along the c axis.
doi:10.1107/S1600536808023738
PMCID: PMC2960484  PMID: 21201652
14.  4,4′,6,6′-Tetra­chloro-2,2′-[(1E,1′E)-propane-1,3-diylbis(nitrilo­methanylyl­idene)]diphenol 
The title compound, C17H14Cl4N2O2, is generated by crystallographic twofold symmetry. The two benzene rings are inclined to one another by 80.17 (10)°. There are two intra­molecular O—H⋯N hydrogen bonds, which make S(6) ring motifs. In the crystal, mol­ecules are linked by C—H⋯O and weak C—H⋯Cl inter­actions, forming a three-dimensional network.
doi:10.1107/S1600536812029443
PMCID: PMC3414188  PMID: 22904795
15.  4,4′,5,5′-Tetra­methyl-2,2′-[1,1′-(propane-1,3-diyldinitrilo)diethyl­idyne]diphenol 
The title Schiff base compound, C23H30N2O2, has crystallographic twofold rotation symmetry. An intra­molecular O—H⋯N hydrogen bond forms a six-membered ring, producing an S(6) ring motif. The imino group is coplanar with the benzene ring. The two benzene rings are almost perpendicular to each other, making a dihedral angle of 87.38 (4)°. In the crystal structure, neighbouring mol­ecules are linked along the c axis by weak inter­molecular C—H⋯O hydrogen bonds and are further packed into columns along the b axis, forming sheets which are parallel to the bc plane.
doi:10.1107/S1600536808027220
PMCID: PMC2960569  PMID: 21201825
16.  Dimethyl 4,4′-dihy­droxy-3,3′-{[(3aRS,7aRS)-2,3,3a,4,5,6,7,7a-octa­hydro-1H-1,3-benzimidazole-1,3-di­yl]bis­(methyl­ene)}dibenzoate 
The title compound, C25H30N2O6, has the imidazolidine ring in an envelope conformation. There are two intra­molecular O—H⋯N hydrogen-bond inter­actions with graph-set motif S(6). The cyclo­hexane ring adopts a slightly distorted chair conformation. One methyl carboxyl­ate substituent forms a dihedral angle of 12.00 (5)° with the plane of the benzene ring, while the other methyl carboxyl­ate group is almost coplanar, making a dihedral angle of 2.26 (9)°. In the crystal, pairs of inter­molecular C—H⋯O hydrogen bonds form racemic dimers, corresponding to an R 2 2(18) graph-set motif. Further weak C—H⋯O inter­actions generate a chain running along the c axis.
doi:10.1107/S1600536811040906
PMCID: PMC3247326  PMID: 22219944
17.  4,4′-Dichloro-2,2′-[2,2-dimethyl­propane-1,3-diylbis(nitrilo­methyl­idyne)]diphenol 
The crystal of the title Schiff base compound, C19H20Cl2N2O2, contains of two crystallographically independent mol­ecules with similar conformations. In each mol­ecule, two intramolecular O—H⋯N bonds generate S(6) motifs. The N atoms are also in close proximity to two H atoms of the dimethyl­propane groups, with H⋯N distances between 2.59 and 2.62 Å. The imine group is coplanar with the benzene ring. The dihedral angles between the benzene rings in the two independent mol­ecules are 58.20 (12) and 47.95 (12)°. The structure displays short inter­molecular Cl⋯Cl [3.3869 (11) Å] and Cl⋯O [3.175 (2)–3.204 (2) Å] inter­actions. The crystal structure is further stabilized by weak inter­molecular C—H⋯O, C—H⋯π and π–π [centroid–centroid distances 3.6416 (13)–3.8705 (14) Å] inter­actions.
doi:10.1107/S1600536808038014
PMCID: PMC2967979  PMID: 21581707
18.  5,5′-Dimeth­oxy-2,2′-[2,2-dimethyl­propane-1,3-diylbis(nitrilo­methyl­idyne)]diphenol 
The asymmetric unit of the title Schiff base compound, C21H26N2O4, consists of four crystallographically independent mol­ecules, viz. A, B, C and D. The A and D, and the B and C mol­ecules are related by a pseudo-inversion centre, and the remaining pairs of mol­ecules differ in the orientations of one of the meth­oxy groups. In each independent mol­ecule, intra­molecular O—H⋯N hydrogen bonds generate two S(6) ring motifs. The dihedral angles between the benzene rings in mol­ecules A, B, C and D are 65.86 (19), 50.41 (19), 68.59 (19) and 50.85 (19)°, respectively. In the crystal structure, mol­ecules are linked by C—H⋯O hydrogen bonds, forming R 2 2(8) dimers. In addition, weak C—H⋯π inter­actions are observed.
doi:10.1107/S1600536808037690
PMCID: PMC2959808  PMID: 21581360
19.  4,4′-Dimeth­oxy-2,2′-[2,2-dimethyl­propane-1,3-diylbis(nitrilo­methanylyl­idene)]diphenol 
In the title compound, C21H26N2O4, the dihedral angle between the substituted benzene rings is 30.47 (15) °. Two strong intra­molecular O—H⋯N hydrogen bonds generate two S(6) ring motifs.
doi:10.1107/S1600536811004776
PMCID: PMC3052006  PMID: 21522371
20.  2,2′-[1,3-Diazinane-1,3-diylbis(methyl­ene)]bis­(4-bromo­phenol) 
The title compound, C18H20Br2N2O2, the heterocyclic ring adopts a chair conformation. The benzene rings make dihedral angles of 86.84 (10) and 60.73 (10)° with the mean plane of the heterocyclic ring. The dihedral angle between the two benzene rings is 79.77 (10)°. The mol­ecular structure is stabilized by two intra­molecular hydrogen bonds between the phenolic hy­droxy groups and N atoms with graph-set motif S(6). The crystal structure is stabilized by weak C—H⋯π inter­actions.
doi:10.1107/S1600536812001985
PMCID: PMC3275243  PMID: 22347099
21.  {2-[(2,6-Difluoro­phen­oxy)meth­yl]phen­yl}boronic acid 
The planes of the two benzene rings in the mol­ecule of the title compound, C13H11BF2O3, form a dihedral angle of 76.06 (3)°; the C—O—C—C torsion angle characterizing the conformation of the central link of the mol­ecule is −79.20 (1)°. The dihydroxy­boron group is not coplanar with the benzene ring bonded to the B atom; one of the C—C—B—O torsion angles is 32.39 (2)°. One of the OH groups of the boronic acid fragment is engaged in an intra­molecular hydrogen bond, whereas the second OH group participates in inter­molecular hydrogen bonding, which leads to the formation of centrosymmetric dimers.
doi:10.1107/S1600536809035235
PMCID: PMC2970217  PMID: 21577817
22.  6,6′-Dieth­oxy-2,2′-[propane-1,2-diyl­bis(nitrilo­methyl­idyne)]diphenol 
In the title mol­ecule, C21H26N2O4, the dihedral angle between the two benzene rings is 88.4 (3)°. Two fairly strong intra­molecular O—H⋯N hydrogen bonds may, in part, influence the mol­ecular conformation.
doi:10.1107/S1600536809003328
PMCID: PMC2968515  PMID: 21582294
23.  (4-Chloro-2-fluoro­phen­yl)[1-(2,6-difluoro­phen­yl)but-3-en­yl]amine 
In the mol­ecule of the title homoallylic amine, C16H13ClF3N, the dihedral angle between the two benzene rings is 84.63 (4)°. Weak intra­molecular N—H⋯F hydrogen bonds generate S(6) and S(5) ring motifs. In the crystal structure, weak inter­molecuar N—H⋯F hydrogen bonds link mol­ecules into centrosymmetric dimers which are arranged in mol­ecular sheets parallel to the ac plane.
doi:10.1107/S1600536809012896
PMCID: PMC2977711  PMID: 21583847
24.  6,6′-Dihydr­oxy-2,2′-[(pentane-1,5-diyl­dioxy)bis­(nitrilo­methyl­idyne)]diphenol 
The mol­ecule of the title compound, C19H22N2O6, assumes a W-shaped configuration with the dihedral angle between the two halves of the mol­ecule being 82.48 (5)°. There is one half-mol­ecule in the asymmetric unit with a crystallographic twofold rotation axis passing through the central C atom of the five methylene groups in the [—CH=N—O—(CH2)5—O—N=CH—] bridge. The dihedral angle formed by the two benzene rings in each mol­ecule of the title compound is 84.18 (4)°. There are strong intra­molecular O—H⋯N and O—H⋯O hydrogen bonds and weak inter­molecular π–π stacking inter­actions between neighbouring benzene rings, and the inter­molecular plane-to-plane distances are 3.488 (2) and 3.841 (3) Å along the b and c axes, respectively. In the crystal structure, inter­molecular O—H⋯O hydrogen bonds link each mol­ecule to two others, forming an infinite three-dimensional supra­molecular structure.
doi:10.1107/S1600536808023064
PMCID: PMC2962213  PMID: 21203294
25.  2,2′-[(2,2′-Bipyridine-3,3′-di­yl)bis­(nitrilo­methyl­idyne)]diphenol 
The title mol­ecule, C24H18N4O2, lies on a twofold rotation axis with a dihedral angle of 73.7 (1)° between the mean planes of the symmetry-related pyridine rings. The dihedral angle between unique benzene and pyridine rings is 8.0 (1)°. An intra­molecular O—H⋯N hydrogen bond may influence the mol­ecular conformation. In the crystal structure, there are weak π–π stacking inter­actions with a centroid–centroid distance of 3.7838 (15) Å.
doi:10.1107/S1600536809032346
PMCID: PMC2970113  PMID: 21577682

Results 1-25 (368739)