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As a follow-up to our research on the chemistry of disubstituted ferrocene derivatives, the synthesis and the structure of the title compound, [Fe(C5H5)(C15H19N)]I·CH2Cl2, is described. The cation molecule is built up from a ferrocene disubstituted by a trimethylammonium methyl group and a phenyl ring. The asymmetric unit contains the iodide to equilibrate the charge and a disordered dichloromethane solvate. The disordered model results from a roughly statistical exchange (0.6/0.4) between one Cl and one H. The packing of the structure is stabilized by weak C—H...X (X = I, Cl), C—H...π(Cp) and C—Cl...π(phenyl) interactions, building a three-dimensional network. The cation has planar chirality with Sp(Fc) absolute configuration. The structure of the title compound is compared with related disubstituted (trimethylammonio)methyl ferrocenes.

As a follow-up to our research on the chemistry of disubstituted ferrocene derivatives, the synthesis and the structure of the title compound, 2-(diphenylphosphinothioyl)-2-(3-oxobut-1-en-yl)ferrocene, [Fe(C5H5)(C21H18OPS)], are described. The molecule is built up from a ferrocene unit disubstituted by an S-protected diphenylphosphine group and by a methylvinylketone chain. The crystal structure features weak C—H...O and C—H...S interactions, which build a two-dimensional network. This structure is compared to that of the related disubstituted diphenylphosphino ferrocene.

The title compound, C17H18ClNO2, was prepared and isolated as a pure diastereoisomer, using column chromatography followed by a succession of fractional crystallizations. Its exact structure was fully identified via 1H NMR and confirmed by X-ray diffraction. It is built up from a central five-membered dihydroisoxazole ring to which a p-chlorophenyl group and a cyclohex-2-enone ring are attached in the 3 and 5 positions. The cyclohex-2-one and isoxazoline rings each exhibit an envelope conformation. The crystal packing features C—H...O, C—H...N and C—H...π interactions, which generate a three-dimensional network.

The title compound, [Mn{SC(O)CF2CH3}(CO)5], has been isolated as a by-product during the reaction of K[Mn(CO)5] with CH3CF2COCl. It is built up from a difluoromethylpropanethioate bonded to an Mn(CO)5 moiety through the S atom. The Mn atom has an almost perfect octahedral coordination sphere. It is one of the rare examples of compounds containing the (CO)5MnS—C fragment. In the crystal, the methyl group occupies a pocket surrounded by the O atoms of three carbonyl groups of the Mn(CO)5 moiety; however, the H...O distances are rather long. These interactions lead to the formation of layers lying parallel to (101), which enclose R44(15) and R44(16) ring motifs. The CF2 group is disordered over two sets of sites with occupancies of 0.849 (3) and 0.151 (3).

A new synthetic alternative to the synthesis of 3-methyl indoles and 3-methyl indoline-2-ols with an excellent atomic economy is presented in this study. It is demonstrated that the intramolecular interrupted hydroaminomethylation (HAM) reaction is a powerful tool for the formation of these compounds, which exhibit wide-ranging biological activity. Several N-Protected-2-vinyl anilines were synthesized and involved in the reaction producing the corresponding 3-methylindole or 3-methyl indoline-2-ol depending on the nature of the N-protecting groups.

The synthesis and characterization of diaquabis[2-(2-hydroxyethyl)pyridine-κ2N,O)nickel(II) dinitrate, [Ni(C7H9NO)2(H2O)2](NO3)2, under ambient conditions is reported and compared with catena-poly[[bis[2-(2-hydroxyethyl)pyridine-κ2N,O]copper(II)]-μ-sulfato-κ2O:O′], [Cu(C7H9NO)2(SO4)]n [Zeghouan et al. (2016). Private communication (refcode 1481676). CCDC, Cambridge, England]. In the two complexes, the 2-(2-hydroxyethyl)pyridine ligands coordinate the metal ions through the N atom of the pyridine ring and the O atom of the hydroxy group, creating a chelate ring. The NiII or CuII ion lies on an inversion centre and exhibits a slightly distorted MO4N2 octahedral coordination geometry, build up by O and N atoms from two 2-(2-hydroxyethyl)pyridine ligands and two water molecules or two O atoms belonging to sulfate anions. The sulfate anion bridges the CuII ions, forming a polymeric chain. The photoluminescence properties of these complexes have been studied on as-synthesized samples and reveal that both compounds display a strong blue-light emission with maxima around 497 nm. From DFT/TDDFT studies, the blue emission appears to be derived from the ligand-to-metal charge-transfer (LMCT) excited state. In addition, the IR spectroscopic properties and thermogravimetric behaviours of both complexes have been investigated.

The title compound, (C15H14N3)[NiCl4]Cl, comprises an NiII cation tetrahedrally coordinated by four chloride anions, a non-coordinating chloride anion and an essentially planar terpyridinium trication (tpyH33+), in which the central pyridinium ring forms dihedral angles of 5.7 (2) and 6.0 (2)° with the peripheral pyridinium rings. Three inter-species N—H...Cl hydrogen bonds are formed with the Cl− anion, which also forms a link between the (tpyH33+) cations through an aromatic C—H...Cl interaction, forming a zigzag chain extending along the 21 (b) screw axis. Two of the anionic Cl atoms of the [NiCl4]2− anions form Ni—Cl...π interactions with separate pyridinium rings [Ni...Cg = 3.669 (3) and 3.916 (4) Å]. In the crystal, successive undulating inorganic and organic layers are formed, extending across the (100) plane. Thermogravimetric and differential thermal analysis (TGA/DTA) indicate that the compound starts to decompose at 313 K and may be a candidate for use as a blue-light luminescent material.

Mn and Fe BPMEN complexes showed excellent reactivity in catalytic oxidation with an excess of co-reagent (CH3COOH). In the straight line of a cleaner catalytic system, volatile acetic acid was replaced by SiO2 (nano)particles with two different sizes to which pending carboxylic functions were added (SiO2@COOH). The SiO2@COOH beads were obtained by the functionalization of SiO2 with pending nitrile functions (SiO2@CN) followed by CN hydrolysis. All complexes and silica beads were characterized by NMR, infrared, DLS, TEM, X-ray diffraction. The replacement of CH3COOH by SiO2@COOH (100 times less on molar ratio) has been evaluated for (ep)oxidation on several substrates (cyclooctene, cyclohexene, cyclohexanol) and discussed in terms of activity and green metrics.

In the title compound, C24H19N3O5S, the thiazole ring (r.m.s. deviation = 0.012 Å) displays a planar geometry and is surrounded by three fragments, two methoxyphenyl and one nitrophenyl. The thiazole ring is almost in the same plane as the nitrophenyl ring, making a dihedral angle of 20.92 (6)°. The two methoxyphenyl groups are perpendicular to the thiazole ring [dihedral angles of 79.29 (6) and 71.31 (7)° and make a dihedral angle of 68.59 (7)°. The molecule exists in an Z,Z conformation with respect to the C=N imine bond. In the crystal, a series of C—H...N, C—H...O and C—H...S hydrogen bonds, augmented by several π–π(ring) interactions, produce a three-dimensional architecture of molecules stacked along the b-axis direction. The experimentally derived structure is compered with that calculated theoretically using DFT(B3YLP) methods.

The crystal structure and the conformation of the title compound, C22H27N3O7S, were determined from the synthetic pathway and by X-ray analysis. This compound is a new 4-thiazolidinone derivative prepared and isolated as pure product from thiosemicarbazone carvone. The molecule is built up from an oxothiazolidine ring tetrasubstituted by a methoxy–oxoethylidene, a maleate, an oxygen and a cyclohexylidene–hydrazone. The cyclohexylidene ring is statistically disordered over two positions, resulting in an inversion of configuration for the substituted carbon.

The title compound, C18H22O4S, an hemisynthetic product, was obtained by the tosylation reaction of the naturally occurring meroterpene p-methoxythymol. The molecule comprises a tetrasubstitued phenyl ring linked to a toluenesulfonate through one of its O atoms. In the crystal, C—H...O and C—H...π interactions link the molecules, forming a three-dimensional network.

The title compound, C16H24Cl2O, was synthesized by treating (1S,3R,8S,9R,10S)-2,2-dichloro-3,7,7,10-tetramethyl-9,10-epoxytricyclo[6.4.0.01,3]dodecane with a concentrated solution of hydrobromic acid. It is built up from three fused rings: a cycloheptane ring, a cyclohexyl ring bearing alkene and hydroxy substituents, and a cyclopropane ring bearing two chlorine atoms. The asymmetric unit contains two molecules linked by an O—H...O hydrogen bond. In the crystal, further O—H...O hydrogen bonds build up an R44(8) cyclic tetramer. One of the molecules presents disorder that affects the seven-membered ring. In both molecules, the six-membered rings display a chair conformation, whereas the seven-membered rings display conformations intermediate between boat and twist-boat for the non-disordered molecule and either a chair or boat and twist-boat for the disordered molecule owing to the disorder. The absolute configuration for both molecules is 1S,3R,8R,9R and was deduced from the chemical pathway and further confirmed by the X-ray structural analysis.

In the title compound, [Zn(C72H44N4O8)(C6H4N2)]·C6H4N2 or [Zn(TPBP)(4-CNpy]·(4-CNpy) [where TPBP and 4-CNpy are 5,10,15,20-(tetraphenylbenzoate)porphyrinate and 4-cyanopyridine, respectively], the ZnII cation is chelated by four pyrrole-N atoms of the porphyrinate anion and coordinated by a pyridyl-N atom of the 4-CNpy axial ligand in a distorted square-pyramidal geometry. The average Zn—N(pyrrole) bond length is 2.060 (6) Å and the Zn—N(4-CNpy) bond length is 2.159 (2) Å. The zinc cation is displaced by 0.319 (1) Å from the N4C20 mean plane of the porphyrinate anion toward the 4-cyanopyridine axial ligand. This porphyrinate macrocycle exhibits major saddle and moderate ruffling and doming deformations. In the crystal, the [Zn(TPBP)(4-CNpy)] complex molecules are linked together via weak C—H...N, C—H...O and C—H...π interactions, forming supramolecular channels parallel to the c axis. The non-coordinating 4-cyanopyridine molecules are located in the channels and linked with the complex molecules, via weak C—H...N interactions and π-π stacking or via weak C—H...O and C—H...π interactions. The non-coordinating 4-cyanopyridine molecule is disordered over two positions with an occupancy ratio of 0.666 (4):0.334 (4).

In the paper by Mouas et al. [Acta Cryst. (2012), E68, m381–m382], there was an error in the name of the first author.

The title compound, C15H25Br3O, was synthesized in one step from a mixture of α-atlantone [2-methyl-6-(4-methylcyclohex-3-en-1-yl)hepta-2,5-dien-4-one] and γ-atlantone [2-methyl-6-(4-methylcyclohex-3-en-1-ylidene)hept-2-en-4-one], which were isolated from an essential oil of the Atlas cedar (Cedrus Atlantica). The molecule is built up from the bromo ethyl cyclohexane ring, which has a substituent bromomethylhexanone group. The cyclohexane ring adopts a chair conformation. In the crystal, molecules are linked by C—H...O hydrogen bonds, forming zigzag chains parallel to [100].

Quaterpyridines have been demonstrated to be useful building blocks in metallo-supramolecular chemistry; however, their synthesis requires the preparation of sensitive building blocks. We present here three examples of nonsymmetric quaterpyridines that were easily obtained in yields of 70–85% by condensation of commercially available enones with 6-acetyl-2,2’:6’,2’’-terpyridine through a Kröhnke pyridine synthesis. Easy access to 6-acetyl-2,2’:6’,2’’-terpyridine starting from 2,6-diacetylpyridine and 2-acetylpyridine is described. The X-ray analysis of a chiral quaterpyridine and its Pt(II) complex is presented.

The title compound, [Fe(C5H5)(C27H24OPS2)], is built up from a ferrocene moiety substituted in the 1- and 2-positions by {[4-(allyloxy)phenyl]sulfanyl}methyl and diphenylthiophosphoryl groups, respectively. The two S atoms lie on opposite sides of the cyclopentadienyl ring plane to which they are attached. In the crystal, C—H...S hydrogen bonds link the molecules into a ribbon running parallel to the (-110) plane. C—H...π interactions link the ribbons to form a three-dimensional network.

The principal building units in the crystal structure of ammonium aquabis(sulfato)lanthanate(III) are slightly distorted SO4 tetrahedra, LaO9 polyhedra in the form of distorted tricapped trigonal prisms, and NH4+ ions. The La3+ cation is coordinated by eight O atoms from six different sulfate tetrahedra, two of which are bidentate coordinating and four monodentate, as well as one O atom from a water molecule; each sulfate anion bridges three La3+ cations. These bridging modes result in the formation of a three-dimensional anionic [La(SO4)2(H2O)]− framework that is stabilized by O—H...O hydrogen-bonding interactions. The disordered ammonium cations are situated in the cavities of this framework and are hydrogen-bonded to six surrounding O atoms.

The asymmetric unit of the title compound, C16H24Cl2O2, contains two independent molecules (A and B) which are built from three fused rings, viz. a seven-membered heptane ring, a six-membered cyclohexyl ring bearing a ketone and an alcohol group, and a cyclopropane ring bearing two Cl atoms. In the crystal, the two molecules are linked via two O—H...O hydrogen bonds, forming an A–B dimer with an R22(10) ring motif. The A molecules of these dimers are linked via a C—H...O hydrogen bond, forming chains propagating along the a-axis direction. Both molecules have the same absolute configuration, i.e. 1S,3R,8R,10S, which is based on the synthetic pathway and further confirmed by resonant scattering [Flack parameter = 0.03 (5)].

The title compound, C13H19N3OS, is a new thiazolidin-4-one derivative prepared and isolated as the pure (3aS,6R)-diastereisomer from (R)-thiosemicarbazone pulegone. It crystallized with two independent molecules (A and B) in the asymmetric unit. The compound is composed of a hexhydroindazole ring system (viz. a five-membered dihydropyrazole ring fused to a cyclohexyl ring) with a thiazole-4-one ring system attached to one of the pyrazole N atoms (at position 2). The overall geometry of the two molecules differs slightly, with the mean planes of the pyrazole and thiazole rings being inclined to one another by 10.4 (1)° in molecule A and 0.9 (1)° in molecule B. In the crystal, the A and B molecules are linked via C—H...O hydrogen bonds, forming slabs parallel to the ab plane. There are C—H...π interactions present within the layers, and between the layers, so forming a three-dimensional structure.

In the title compound, C26H21N3O5S, the thiazole ring is nearly planar with a maximum deviation of 0.017 (2) Å, and is twisted with respect to the three benzene rings, making dihedral angles of 25.52 (12), 85.77 (12) and 81.85 (13)°. In the crystal, weak C—H...O hydrogen bonds and C—H...π interactions link the molecules into a three-dimensional supramolecular architecture. Aromatic π–π stacking is also observed between the parallel nitrobenzene rings of neighbouring molecules, the centroid-to-centroid distance being 3.5872 (15) Å.

The title compound, C17H27NO, crystallizes with three independent molecules in the asymmetric unit with almost identical conformations. Each molecule is built up from a seven-membered ring to which a bridged six-membered ring is fused. In each of the three molecules, the seven-membered rings have a twist-chair conformation, while the cyclohexenyl rings display perfect boat conformations. In the crystal, N—H...O hydrogen bonds link the molecules into zigzag chains running along the b-axis direction.

All the non-H atoms of the title compound, C15H17NO2, except the CH3 groups of the isopropyl unit and the O atoms of the nitro group, lie on a crystallographic mirror plane. The dihedral angle between the naphthalene plane and the nitro group is constrained to be 90° by symmetry. In the crystal, molecules are linked by π–π interactions [centroid–centroid separation = 3.6591 (4) Å] and stacked along the b-axis direction.

The title compound, C17H19NO3, was synthesized in three steps from a mixture of α-, β- and γ-himachalene, which was isolated from an essential oil of the Atlas cedar (Cedrus atlantica). The dihedral angle between the two rings of the naphthalene moiety is 2.54 (5)°. The nitro group and the acetyl group lie almost normal to the mean plane of the naphthalene moiety, making dihedral angles of 80.29 (13) and 83.01 (15)°, respectively, and are inclined to one another by 13.23 (19)°. There is an intramolecular C—H...O hydrogen bond present involving a nitro O atom and the H atom of the methine C atom of the isopropyl group, forming an S(6) ring motif. In the crystal, molecules are linked by pairs of C—H...π interactions, forming inversion dimers. There are no other significant intermolecular interactions present.

The title compound, C16H22Br4, was synthesized in two steps from β-himachalene, which was isolated from essential oil of the Atlas cedar (cedrus atlantica). It is built up from three fused rings, a seven-membered heptane ring, a six-membered cyclohexyl ring bearing both a bromine and a bromomethyl substituent, and a three-membered propane ring bearing two Br atoms. In the crystal, molecules are linked by C—H...Br hydrogen bonds, forming chains propagating along [001]. The absolute configuration was deduced from the chemical pathway and confirmed by resonant scattering [Flack parameter = 0.012 (10)].

The title compound, C18H26Cl2N2O, was synthesized in four steps from β-himachalene (3,5,5,9-tetramethyl-2,4a,5,6,7,8-hexahydro-1H-benzocycloheptene), which was isolated from an essential oil of the Atlas cedar (Cedrus atlantica). It crystallizes with two independent molecules in the asymmetric unit. Each molecule is built up from fused six- and seven-membered rings and an appended three-membered ring. An acetylhydrazone substituent is attached to the six-membered ring. In both molecules the six-membered rings display half-chair conformations, whereas the seven-membered rings have boat conformations. In the two molecules, the mean planes of the two rings are inclined to one another by 59.9 (3) and 59.1 (3)°. In the crystal, the two molecules are linked via N—H...O hydrogen bonds, forming dimers with an R22(8) loop. Within the dimer there are also C—H...O hydrogen bonds present. The dimers are linked via C—H...Cl hydrogen bonds, forming slabs parallel to the ab plane.

The title compound, C16H24O3, is built up from three fused rings, a six-membered, a seven-membered and a three-membered ring. The absolute configuration of the title compound was determined as (1R,3S,8R,11R) based on the synthetic pathway. The six-membered ring has an half-chair conformation whereas the seven-membered ring displays a boat conformation. In the cyrstal, C—H...O hydrogen bonds build up a two-dimensional network parallel to (0 0 1). The crystal studied was an inversion twin with a minor twin component of 34%.

The title compound, C16H24Cl2O, is built up from two fused six- and seven-membered rings which bear a dichlorocyclopropane group and an epoxy group, respectively. In the molecule, the six-membered ring adopts an envelope configuration with the C atom linking the epoxy ring at the flap, while the seven-membered ring adopts a boat–sofa conformation.

The asymmetric unit of the title compound, 2C5H6N5+·SiF62−·2H2O, contains one adeninium cation, half of a hexafluoridosilicate anion located on an inversion centre and one lattice water molecule. The adeninium cations are connected through N—H...N hydrogen bonds involving one H atom of the –NH2 group and the H atom of the protonated N atom of the adenine ring system, forming centrosymmetric ring motifs of the type R22(10) and R22(8), respectively. The overall connection of the cation leads to the formation of planar ribbons parallel to (122). In the ribbons, slipped π–π stacking interactions, with a centroid-to-centroid distance of 3.6938 (9) Å, an interplanar distance of 3.455 Å and a slippage of 1.306 Å is observed. The hexafluoridosilicate anion and the water molecule are linked through O—H...F hydrogen bonds [ring motif R44(12)] into chains parallel to [100]. The cationic ribbons and anionic chains are finally connected through additional N—H...O, N—H...F and O—H...F hydrogen bonds into a three-dimensional network in which layers of adeninium cations and fluoridosilicate anions alternate parallel to (001).

The title compound, C27H34O2, was hemisynthesized through direct benzoylation of the naturally occurring meroterpene totarol. The central fused six-membered ring has a half-chair conformation, whereas the terminal six-membered ring displays a chair conformation. The dihedral angle between the fused benzene ring and the benzoyl benzene ring is 73.05 (14)°. The S,S chirality of the molecule is consistent with the synthetic pathway, and confirmed by the refinement of the Flack parameter.

The title compound, C16H24Br2O, was synthesized from the reaction of β-himachalene (3,5,5,9-tetramethyl-2,4a,5,6,7,8-hexahydro-1H-benzocycloheptene), which was isolated from Atlas cedar (Cedrus atlantica). The asymmetric unit contains two independent molecules with similar conformations. Each molecule is built up from two fused seven-membered rings and an additional three-membered ring. In both molecules, one of the seven-membered rings has a chair conformation, whereas the other displays a screw-boat conformation.

The title compound, C16H26O, was synthesized by treating (1S,3S,8R)-3,7,7,10-tetramethyltricyclo[6.4.0.01,3]dodec-9-ene with metachloroperbenzoic acid. The molecule is built up from two fused six- and seven-membered rings. The six-membered ring has a half-chair conformation, whereas the seven-membered ring displays a boat conformation. In the crystal, there are no significant intermolecular interactions present.

The reaction of CoII(TpivPP) {TpivPP is the dianion of 5,10,15,20-tetrakis[2-(2,2-dimethylpropanamido)phenyl]porphyrin} with an excess of KCN salts and an excess of the 18-crown-6 in chlorobenzene leads to the polymeric title compound catena-poly[[dicyanido-2κ2C-(1,4,7,10,13,16-hexaoxacyclooctadecane-1κ6O){μ3-(2α,2β)-5,10,15,20-tetrakis[2-(2,2-dimethylpropanamido)phenyl]porphyrinato-1κO5:2κ4N,N′,N′′,N′′′:1′κO15}cobalt(III)potassium] dihydrate], {[CoK(CN)2(C12H24O6)(C64H64N8O4]·2H2O}n. The CoIII ion lies on an inversion center, and the asymmetric unit contains one half of a [CoIII(2α,2β-TpivPP)(CN)2]− ion complex and one half of a [K(18-C-6]+ counter-ion (18-C-6 is 1,4,7,10,13,16-hexaoxacyclooctadecane), where the KI ion lies on an inversion center. The CoIII ion is hexacoordinated by two C-bonded axial cyanide ligands and the four pyrrole N atoms of the porphyrin ligand. The KI ion is chelated by the six O atoms of the 18-crown-6 molecule and is further coordinated by two O atoms of pivalamido groups of the porphyrin ligands, leading to the formation of polymeric chains running along [011]. In the crystal, the polymeric chains and the lattice water molecules are linked by N—H...O and O—H...N hydrogen bonds, as well as weak C—H...O, O—H...π and C—H...π interactions into a three-dimensional supramolecular architecture.

The hemisynthesis of the title compound, C22H32O2, was carried out through direct acetylation reaction of the naturally occurring diterpene totarol [systematic name: (4bS,8aS)-4b,8,8-trimethyl-1-propan-2-yl-5,6,7,8a,9,10-hexahydrophenanthren-2-ol]. The molecule is built up from three fused six membered rings, one saturated and two unsaturated. The central unsaturated ring has a half-chair conformation, whereas the other unsaturated ring displays a chair conformation. The absolute configuration is deduced from the chemical pathway. The value of the Hooft parameter [−0.10 (6)] allowed this absolute configuration to be confirmed.

The absolute configuration of the title compound, C16H24O, has been deduced from the chemical pathway. The six-membered ring has a roughly half-chair conformation with the quaternary C atom as the flap. The seven-membered ring displays a chair conformation. In the crystal, there is a weak C—H...O hydrogen bond between the methylene group of the cyclopropane ring and the carbonyl group of a screw-axis-related molecule, which builds up a zigzag-like chain along the b-axis direction.

The title compound, C16H24Br2O was synthesized by three steps from β-himachalene (3,5,5,9-tetramethyl-2,4a,5,6,7,8-hexahydro-1H-benzocycloheptene), which was isolated from essential oil of the Atlas cedar (Cedrus atlantica). The molecule is built up from a seven-membered ring to which a six- and a three-membered ring are fused. The six-membered ring shows a chair conformation. One C atom in the seven-membered ring and two methyl groups attached to the ring are disordered over two sets of sites, with an occupancy ratio of 0.658 (7):0.342 (7).

The absolute configuration of the title compound, C16H23BrCl2, has been deduced from the chemical pathway and fully confirmed by refinement of the Flack and Hooft parameters. The six-membered ring adopts a half-chair conformation, whereas the seven-membered ring is a twisted chair. The molecular packing within the crystal is stabilized only by van der Waals interactions.

The title compound, C16H24Cl2O, was synthesized in three steps from β-himachalene (3,5,5,9-tetramethyl-2,4a,5,6,7,8-hexahydro-1H-benzocycloheptene), which was isolated from essential oil of the Atlas cedar (cedrus atlantica). The asymmetric unit contains two independent molecules with similar conformations. Each molecule is built up from two fused seven-membered rings and an additional three-membered ring arising from the reaction of himachalene with dichlorocarbene. The dihedral angles between the mean planes of the two seven-membered rings are 75.03 (9) and 75.02 (9)° in the two independent molecules.

In the title Schiff base salt, C16H13N2O+·ClO4−, the pyridine ring and the naphthalene ring system are approximately co-planar [making a dihedral angle of 6.05 (12)°] and an intramolecular O—H...N hydrogen bond occurs between the hydroxyl and imino groups. In the crystal, the cations and anions are linked by N—H...O and weak C—H...O hydrogen bonds, forming the supramolecular layers parallel to (100). The crystal studied was an inversion twin refined with minor component = 0.43 (13).