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(S)-(−)-1-Phenylethanaminium 4-(2,4,6-triisopropylbenzoyl)benzoate (S-PEATPBB) undergoes a photochemical reaction in its crystalline form upon UV irradiation and forms three different products: the first product is the result of a Yang cyclization with the participation of the δ-H atom of o-isopropyl (product D) and the second and third products are obtained via a Norrish–Yang reaction with the involvement of the γ-H atom of 2-isopropyl (product P) and 6-isopropyl (product Z). These products are formed in different proportions (D > P >> Z). The path and kinetics of the reaction were monitored step-by-step using crystallographic methods, both under ambient and high-pressure conditions. The reactivity of S-PEATPBB depends strongly on the geometry of the reaction centre and the volume of the reaction cavity. Due to the geometrical preferences making the cyclization reaction easier to proceed, product D dominates over the other products, while the formation of product Z becomes difficult or almost impossible at high pressure. The reaction proceeds with an increase of the unit-cell volume, which, suppressed by high pressure, results in a significant decrease of the reaction rate. The crystal lattice of S-PEATPBB shows high elasticity. The quality of the partially reacted crystal remains the same after decompression from 0.75 GPa to 0.1 MPa.

The kinetics of the photochemical Norrish-Yang reaction in single crystals was studied using the example of 1,3,5,7-tetraazatricyclo[3.3.1.13,7]decane 4-(2,4,6-triisopropylbenzoyl)benzoate by X-ray...

To examine the influence of both the important π-acceptor character of the 4-cyanopyridine ligand and the nature of the para-substituted phenyls of meso-porphyrins on the electronic, electrochemical and structural properties of cobaltous metalloporphyrins, we prepared and fully characterized two coordination compounds: the (4-cyanopyridine)[meso-tetra(para-methoxyphenyl)porphyrinato]cobalt(II) and the (4-cyanopyridine)[meso-tetra(para-chlorophenyl)porphyrinato]cobalt(II) with the [CoII(TMPP)(4-CNpy)] and [CoII(TClPP)(4-CNpy)] formulas (complexes 1–2). The solution structures of compounds 1–2 were confirmed by 1H NMR spectroscopy and mass spectrometry methods. They were further characterized by cyclic voltammetry and photoluminescence studies. The X-ray molecular structure data show that the Co-TClPP-4-NCpy derivative (2) exhibits high ruffling deformation compared to that of the Co-TMPP-4-CNpy species (1). Notably, the crystal packing of complex 1 shows the formation of Co⋯Co supramolecular dimers with a distance of 5.663 A. As an application of our two cobaltous compounds, an investigation involving complexes 1–2 in the degradation of the methylene blue dye in the presence and absence of H2O2 in aqueous solutions was carried out. These promising results show that 1–2 can be used as catalysts in the degradation processes of dyes.

International audience; A novel magnesium(II) metalloporphyrin namely the bis(4-pyrrolidinopyridine)[meso-tetra(p-tolyl)porphyrinato)]magnesium(II) dichloromethane desolate complex with the formula [Mg(TTP)(4-pypo)2]·CH2Cl2 (I) has been synthetized and fully characterized by UV–Vis, fluorescence, IR, 1H NMR spectroscopy and mass spectrometry. The X-ray molecular structure shows that I presents two molecules (1 and 2) [Mg1(TTP)(4-pypo)2] and [Mg2(TTP)(4-pypo)2] in the asymmetric unit while the Hirshfeld surface analysis on this hexacoordinated Mg(II) porphyrin species indicates that the crystal lattice is mainly sustained by C__H…C, C__H…Cg (Cg is the centroid of a phenyl ring) and C__H…Cl intermolecular interactions. The cyclic voltammetry data of I is also reported. The bioactivity of the H2TTP, the [Mg(TTP)] starting material and [Mg(TTP)(4-pypo)2]·CH2Cl2 (I) was evaluated in vitro, by examining their inhibitory effect against three strains of Candida viz. C. albicans, C. glabrata and C. tropicalis with MIC values in the range 2.5 to 10 µg.mL−1. The screening of the susceptibility of M. canis and T. rubrum clinical strains on the three porphyrinic derivatives is also reported.

The influence of pressure on the course of [4+4] photodimerization in crystals of 9-methylanthracene is presented. The studies were performed at 0.1 and 0.4 GPa. As a result of the reaction at high pressure, crystals of the pure product were obtained, which allowed for monitoring of the reaction until its completion. The initial increase in the unit-cell volume caused by the reaction under ambient conditions was reduced at high pressure due to the decrease in the void volume. Despite the smaller size of the void volume at high pressure, dimer molecules formed during the reaction changed the orientation of the monomer molecules in the crystal structure. The size of the voids above the terminal rings of the monomers correlates with the position of the terminal rings in the dimer. The reaction rate increased at high pressure, indicating that the decrease in the distance between adjacent monomers caused by pressure dominates over the decrease in the void volume. This distance is statistically constant as the reaction progresses, contrary to the reaction at ambient pressure.

Molecules of trans-4-chlorocinnamide were arranged in a head-to-tail fashion and under UV–vis irradiation underwent [2 + 2] photodimerization. The photochemical reaction was conducted at ambient pressure (0.1 MPa) and at high pressure of 0.5 GPa, 1.5 GPa and 2.0 GPa in a step-by-step manner. This enabled us to monitor the photo-induced changes in the unit cell parameters, intramolecular geometry, free space between molecules and intermolecular contacts. The crystals at high pressure were cracking faster than in ambient conditions, which was explained by the lack of sufficient free space in the crystals. The high pressure also had an impact on the size of changes during the [2 + 2] photoreaction: the higher the pressure, the smaller the changes occurred. A slight rotation of reactant molecules during the photoreaction was observed and the angle between the molecular plane and the (100), (010) and (001) planes was monitored for the studied pressures. The dependence between the initial distance for reactant molecules and the size of the changes that took place during the [2 + 2] photoreaction for the head-to-tail molecular architecture was described. We also showed that the [2 + 2] photodimerization, and not pressure, can have a bigger impact on intermolecular interactions.

International audience; In this work, a new cadmium(II) complex namely the (1,4-diazabicyclo[2.2.2]octane)(meso-tetrakis(4-tert-methoxyphenyl)porphyrinato)cadmium(II) with the formula [Cd(TMPP)(DABCO)] (I) (DABCO = 1,4-diazabicyclo[2.2.2]octane) was successfully synthetized. The structure of (I) have been characterized by FT-IR, 1HNMR, UV–visible, fluorescence spectroscopies and single crystal X-ray diffraction technique. DFT calculations has been made for the structural, 1H NMR spectroscopy and IR spectra analysis. The adsorption of methylene blue (MB) dye was studied to examine the efficiently of the [Cd(TMPP)(DABCO)] for removing the cationic dyes from aqueous solution. The Langmuir adsorption capacity (Q0max) at 290 K and pH 7.0 was found to be 69.24 mg.g−1. The adsorption mechanism which involved π-π interaction between the MB dye molecule and the porphyrin ring of (I) is well described by the pseudo second-order and Elovich models.

Synthesis of a new iron(III) metalloporphyrin complex is achieved. Molecular structure, supramolecular assembly and physico-chemical properties have been explored by means of experiments and comput...

New Pd(II) complex, trans-[PdCl2(7AI3CAH)2], containing 7-azaindole-3-carboxaldehyde (7AI3CAH) and the dinuclear complex [Pd2(7AI3CA)4]·DMSO with the deprotonated ligand (7AI3CA) have been prepared and characterized by X-ray crystallography, infrared and Raman spectroscopy, DFT calculations and antiproliferative activity studies. A single crystal X-ray analysis of [Pd2(7AI3CA)4]·DMSO has shown that the complex crystallizes in Cmca space group with the following unit cell dimensions: a = 15.6593(9), b = 17.9444(8), c = 13.8915(7) A, V = 3903.5(3) A3, Z = 4. Two ligands and DMSO solvate molecule are disordered. In this complex, the Pd24+ unit is surrounded by four N-deprotonated 7AI3CA− anions with a Pd–Pd distance of 2.7122(12) A. Vibrational spectroscopic studies have revealed that in trans-[PdCl2(7AI3CAH)2] complex, palladium(II) is bound to two pyridine nitrogen atoms of 7AI3CAH and to two chloride ions, in a square-planar trans arrangement. Comprehensive DFT calculations (including geometry optimizations, theoretical vibrational spectra and HOMO/LUMO orbitals) were performed for the four possible isomers of the dinuclear complex [Pd2(7AI3CA)4] and for two isomers of [PdCl2(7AI3CAH)2] using the B3LYP method with the 6–311++G(d,p)/LanL2DZ basis sets. The results have shown that the most stable isomers are: cis-(2,2)-[Pd2(7AI3CA)4] for the dinuclear complex and trans-[PdCl2(7AI3CAH)2] for the mononuclear complex. Detailed vibrational assignments of the experimental infrared and Raman spectra of both the palladium(II) complexes have been made on the basis of the calculated potential energy distributions (PEDs). The antiproliferative activity of trans-[PdCl2(7AI3CAH)2] has been tested against the following human cancer cell lines: T47D and MCF7 (breast cancer), A549 (lung carcinoma), A2780 (ovarian cancer) and one normal cell line BALB/3T3 (mouse fibroblast). The trans-[PdCl2(7AI3CAH)2] has revealed a remarkable cytotoxicity against the T47D tumour cell line (IC50 = 4.77 ± 1.61 μM), which is over three-times higher than the clinically used cisplatin (IC50 = 16.3 ± 3.9 μM). A study on stability of trans-[PdCl2(7AI3CAH)2] in DMSO solution has been performed by FT-IR (ATR) spectroscopy.

The molecular structures of three porphyrinate derivatives have been determined by X-ray studies. Two derivatives, [Fe(TTP)(1-MeIm)[Formula: see text]] · 2C[Formula: see text]H[Formula: see text] and [Fe(T-[Formula: see text]-OCH[Formula: see text]PP)(BzHIm)[Formula: see text]] are iron(II) derivatives, whereas the third, [Fe(TMP)(BzHIm)[Formula: see text]]ClO[Formula: see text] · 2CHCl[Formula: see text], is an iron(III) species. The structure determinations provide evidence of the importance of steric effects, either from the axial ligand or the porphyrin ligand, in defining the overall stereochemistry.

The influence of the molecular environment and the intramolecular features on the [2 + 2] photodimerization of 2,5-difluorocinnamic acid (1) and 3,5-difluorocinnamic acid (2) in crystals were analyzed. The crystal structures of (1) were determined at pressures of 0.1 MPa and 0.3 and 0.9 GPa before the [2 + 2] photodimerization as well as for several steps of the reaction. The determined structures revealed the influence of pressure on the reaction rate: the reaction was faster at 0.3 GPa than at 0.1 MPa, but there was not a significant difference between the rates at 0.3 and 0.9 GPa. For (2), the crystal structure was determined before the photochemical reaction, and the unit cell parameters were monitored along with the reaction progress at 0.1 MPa and 0.4 GPa, which showed higher reactivity of (2) at 0.4 GPa. Despite the similar orientations, distances between two neighboring monomers, and volumes of free space in the studied compounds, (2) reacted noticeably worse than (1). The differences in reactivit...

Structures and vibrational spectra of 3-bromo-7-azaindole (3Br7AI), 4-bromo-7-azaindole (4Br7AI), 4-chloro-7-azaindole (4Cl7AI), 5-bromo-3-chloro-7-azaindole (5Br3Cl7AI) and 3-bromo-4-chloro-7-azaindole (3Br4Cl7AI) have been investigated. For the first time a single crystal analysis is reported for the three compounds: 3Br7AI (P21/n space group; a = 12.6586(3), b = 3.98664(12), c = 14.1189(4)A, β = 100.901(2)o, Z = 4); 4Br7AI (P21/n space group; a = 5.38136 (13), b = 9.2262 (2), c = 13.9806 (4)A, β = 90.052 (2)o, Z = 4); and 5Br3Cl7AI (C2/c space group; a = 22.9444(10), b = 3.91953(12), c = 17.8500(6)A, β = 102.621(4)o, Z = 8). In the crystal structure, a pair of molecules forms a centrosymmetric dimer connected by dual nearly linear N H⋯N hydrogen bonds between the pyrrole and pyridine rings. In addition, the structures of 4Br7AI and 5Br3Cl7AI are stabilized by C2 H2⋯Br hydrogen bonds. The IR and Raman spectra of all compounds and their N-deuterated derivatives were recorded in the solid state. The theoretical molecular structures and vibrational spectra of the centrosymmetric dimers of five investigated compounds were calculated using the B3LYP method with the 6-311G++(d,p) basis set. The optimized structural parameters and the calculated vibrational spectra reproduce well the experiment. Detailed vibrational assignments for all these compounds have been made on the basis of the calculated potential energy distributions (PEDs). The characteristic marker bands for the chloro- and bromo-derivativeds of 7-azaindoles are reported.

The (tert-butyl isocyanide)(5,10,15,20-{tetrakis-[4-(benzoyloxy)phenyl]porphyrinato}iron(II) coordination compound with the formula [FeII(TPBP)(t-BuNC)2] (I) was prepared by the reduction of the triflato iron(III) starting material [FeIII(TPBP)(SO3CF3)] using a large excess of tert-butyl isocyanide. The UV-visible titration and IR spectra indicated that (I) is an iron(II) porphyrin derivative. A solid-state Mossbauer investigation of this species showed that the quadrupole splitting (ΔEQ) and the isomer shift (δFe) values are small [ΔEQ = 0.20 (1) mm.s−1 and δFe = 0.22 (1) mm.s−1 at 300 K]. These values are very close to those of the known bis(carbonyl) and the bis(cyano) iron(II) porphyrins. This indicates that (I) is a low-spin (S = 0) iron(II) metalloporphyrin where the t-BuNC is a good π-acceptor moiety comparable to the CN− and CO ligands. The X-ray molecular structure confirms the low-spin character of (I) where the average equatorial Fe(II)—N(pyrrole) bond length is 2.007 (2) A. In the crystal, the [FeII(TPBP)(t-BuNC)2] molecules are linked together via weak C—H….O and C—H….Cg (Cg is the centroid of a pyrrole or a phenyl ring) intermolecular interactions forming two-dimensional chains parallel to the c axis.

A novel two-dimensional coordination polymer, catena-poly[(μ2-7-azaindole-3-carboxylato-O:N)-di-aqua-sodium], [Na(7AI3CAH)(H2O)2]n has been synthesized and investigated by a single crystal X-ray diffraction, vibrational spectroscopy and DFT calculations. The sodium complex crystallizes in the triclinic system, space group Pī with a = 7.2226 (4), b = 7.4342 (7), c = 8.8428 (8) A, α = 103.568 (8), β = 93.425 (6), γ = 91.233 (6)°, V = 460.42 (7) A3 and Z = 2. The asymmetric unit contains two crystallographically independent, half occupied sodium cations surrounded by one 7AI3CAH anion and two water molecules. The O-deprotonated 7-azaindole-3-carboxylate ligand (7AI3CAH) bridges the adjacent Na ions via one oxygen atom of the carboxylate group and via the pyridine nitrogen atom of the 7-azaindole group, which is quite unusual. The sodium cations are six-coordinated in a distorted octahedral geometry, where two apical positions are occupied by two water molecules. Extensive intermolecular N H⋯O and O H⋯O hydrogen bonds stabilize the crystal structure of the complex. The infrared and Raman spectra of [Na(7AI3CAH)(H2O)2]n were recorded in the solid state. The theoretical wavenumbers, infrared intensities, Raman scattering activities and Raman intensities were calculated at the B3LYP/6-311++G(d,p) level for a theoretical model of the title compound including an inter ligand N H⋯O(aqua) interaction. A detailed vibrational assignment has been made on the basis of the calculated potential energy distribution.

The path of the Norrish–Yang reaction of methylammonium 4-(2,4,6-triisopropylbenzoyl)benzoate was studied by means of X-ray structure analysis. The following parameters influenced by this photochemical reaction were monitored: (a) intramolecular distances and angles in the reaction center, (b) the size of the free space near the reactive atoms, (c) the mutual orientation of molecular fragments, (d) the cell parameters, and (e) the product content. Product molecules were created in two modes, namely, by the reaction of the 2-isopropyl or 6-isopropyl group, which has not been revealed previously for other 2,4,6-triisopropylbenzophenones. The 2-isopropyl group took part in the photochemical reaction during the whole crystal transformation, whereas the reaction of the 6-isopropyl group started with a delay and ceased before the total crystal conversion. The reason for such behavior was explained by the analysis of changes in the free space near both o-isopropyl groups with the crystal phototransformation.

A single crystal X-ray analysis, FTIR and FT-Raman spectroscopic studies and the B3LYP/6–311++G (p,d) calculations were performed for 7-azaindole-3-carboxaldehyde, 1H-pyrrolo [2,3-b]pyridine-3-carbaldehyde (7AI3CA). This compound is an important building block of antibacterial, antifungal and anticancer agents. It crystallizes in the monoclinic system (space group P21/c) with a = 3.83610 (13), b = 18.0442 (6), c = 9.9572 (4) A, β = 96.682 (3)°, V = 684.55 (4) (A3) and Z = 4. In the crystal structure, the 7AI3CA molecules form a dimer linked by the moderately strong, dual and nearly linear N H⋯N intermolecular hydrogen bonds between the pyrrole and pyridine rings. In addition, each dimer is held together with the neighboring molecules via C H⋯O intermolecular interactions, which play an important role in stabilizing the crystal structure. The optimized geometry and the calculated vibrational spectra of a trimer linked by N H⋯N and C H⋯O intermolecular hydrogen bonds show very good agreement with the experiment. Detailed vibrational assignments of the experimental IR and Raman spectra have been made on the basis of the potential energy distribution (PED), calculated for a trimer of 7AI3CA.

The path of the Norrish–Yang reaction in crystals of propylamine 4-(2,4,6-triisopropylbenzoyl)benzoate was monitored under ambient pressure by means of single-crystal XRD experiments. The crystal structures containing product and reactant molecules in various proportions, i.e. for various stages of the reaction, were determined. The reaction was successfully monitored until 30% conversion. During the reaction, both o-isopropyl groups created product molecules, however, at different rates. In search of the reasons for such photochemical behaviour of reactant molecules, the intramolecular geometry, size and shape of free space and intermolecular interactions were analyzed. It occurred that the intermolecular interactions had the crucial significance for the reactivity. The progress of the Norrish–Yang reaction in crystals under a high pressure of 1.0 GPa was monitored based on the changes in the cell constants. The high-pressure structure of the pure reactant crystal was determined at 1.0 GPa. Comparison of high and ambient-pressure structures revealed a similarity in the intramolecular geometry and significant changes in the area of molecules, which can influence the photochemical behaviour of the compound at high pressure. The characteristics and the size of the structural changes brought about by the Norrish–Yang reaction are different at ambient and high pressures.

To examine the influence of both the important π-acceptor character of the 4-cyanopyridine ligand and the nature of the

The precursor (5,10,15,20)-tetratolylporphyrin (H2TTP) (1) and Zn(II) complex (5,10,15,20)-tetratolylporphyrinato)zinc(II) [Zn(TTP)] (2) have been synthesized and utilized to afford a novel complex (3) bearing pyrazine as fifth coordination site on axial position, i.e. (pyrazine)(5,10,15,20-tetratolylporphyrinato)zinc(II) hemi-pyrazine hemidichloromethane solvate [Zn(TTP) (pyz)]0.0.5(pyz.CH2Cl2). Photophysical, electrochemical and X-ray diffraction were investigated. The single-crystal X-ray analysis indicated that in complex (3) (i) Zn(II) ion is penta coordinated, (ii) slight displacement of Zn atom by −0.28 A towards the axial ligand (pyrazine) and (iii) the crystal lattice is made up of two dimensional layers stabilised by C−H…Cg intra- and intermolecular interactions (Cg is the centroid of pyrrole ring). Optical absorption studies revealed a redshifted of the Soret (B) and Q bands of the Zn-porphyrins complexes. Contrarily, a hypsochromic shift of Q bands in emission spectra of the complexes is noted as compared to the H2TPP. Lifetime of the electrons in (1–3) were determined and compared. Overall, this study would assist in understanding the impact of incorporation of pyrazine at the axial position on optical and electronic properties. Cyclic voltammetry (CV) was applied for the study of the electrochemical behavior of both (2) and (3) complexes in 0.2 M Tetra-n-butyl ammonium perchlorate (TBAP) solution in CH2Cl2. The results of electrochemical confirmed the potentials redox peaks shift more negative ca 60 mV to that is caused by the coordination of pyrazine ligand.

The crystal structure was determined for the first time for 4-[(di-p-tolyl-amino)benzylidene]-(5-pyridin-4-yl-[1,3,4]thiadiazol-2-yl)-imine (trans-PPL9) by X-ray diffraction. The imine crystallized in the monoclinic P21/n space group with a = 18.9567(7) Å, b = 6.18597(17) Å, c = 22.5897(7) Å, and β = 114.009(4)°. Intermolecular interactions in the PPL9 crystal were only weak C−H∙∙∙N hydrogen bonds investigated using the Hirshfeld surface. The electronic and geometric structure of the imine were investigated by the density functional theory and the time-dependent density-functional theory. The properties of the imine in neutral and protonated form with camforosulphonic acid (CSA) were investigated using cyclic voltammetry, UV–vis and 1H NMR spectroscopy. Theoretical and experimental studies showed that for the 1:1 molar ratio the protonation occured on nitrogen in pyridine in the PPL9 structure, as an effect of Brönsted acid–base interactions. Thermographic camera was used to defined defects in constructed simple devices with ITO/PPL9 (or PPL9:CSA)/Ag/ITO architecture. In conclusion, a thermally stable imine was synthesized in crystalline form and by CSA doping, a modification of absorption spectra together with reduction of overheating process was observed, suggesting its potential application in optoelectronics.

Two new complexes of Cd(II) with an O-deprotonated anion of 5-methoxyindole-2-carboxylic acid (5-MeOI2CA), of the formulas [Cd(5-MeOI2CA) 2 (H 2 O) 2 ] n ( 1 ) and [Cd 3 (5-MeOI2CA) 6 (H 2 O) 4 (DMSO) 4 ]⋅2DMSO ( 2 ) were synthesized. In the polymeric complex 1 , the 5-MeOI2CA anion acts as a bidentate bridging ligand and the coordination environment around the Cd(II) ion can be described as a distorted octahedron. Single crystal X-ray diffraction analysis of 2 has revealed that this complex is a trimer and it crystallizes in the monoclinic system (space group P 2 1 / c with a = 20.3403(4), b = 14.3079(2), c = 15.0603(3) A, β = 92.4341(17)°, V = 4379.00(14) A 3 and Z = 2). In 2 , the 5-MeOI2CA anions act as bidentate bridging and bidentate chelating ligands. The asymmetric unit of 2 contains two crystallographically independent Cd(II) cations. One of the cations is coordinated to six oxygen atoms and shows an octahedral geometry with a rhombic deformation. The other Cd(II) cation adopts a distorted seven-coordinate pentagonal-bipyramidal geometry involving seven oxygen atoms. In 2 , the DMSO solvent molecules play a key role in the formation of metal-organic frameworks by filling voids, which are created by the bridging and chelating 5-MeOI2CA anions, the cadmium cations and the other DMSO molecules coordinated to cadmium. Comprehensive theoretical calculations (including the optimized structural parameters, harmonic frequencies and vibrational intensities) were performed for 2 using the B3LYP method with the 6–311++G(d,p)/LanL2DZ basis sets. The infrared and Ramana spectra were measured and a detailed assignment of the experimental spectra of 2 was performed. All cadmium-oxygen stretching vibrations occur in the range below 400 cm −1 .

The X-ray diffraction studies of the salt of 6,6-diethyl-5-oxo-5,6,7,8-tetrahydronaphthalene-2-carboxylic acid with (1 S )-1-(4-methylphenyl)ethylamine were carried out at high pressure. The compound underwent the Norrish-Yang reaction in crystals brought about by UV–vis radiation. In order to understand the photoreactivity of the compound at high pressure, the structures of pure reactant crystals at 0.1 MPa and 1.8 GPa were compared in terms of the intramolecular geometrical parameters, the intermolecular interactions, the free space, the size of the reaction cavity and the cell parameters, which all changed with pressure. The course of the photochemical reaction was monitored at 1.0 GPa and 1.8 GPa. The changes in the unit cell parameters indicated that the reaction proceeded faster at 1.0 GPa than at 1.8 GPa, which was connected with the decrease of the volume of the reaction cavity and the increase of the intermolecular interactions at high pressure.

The mol­ecular structure of the piperazine[5,10,15,20-(tetra­phenyl­benzoate)porphyrinato-κ4 N]zinc(II) complex is composed of parallel pairs of layers with an inter­layer distance of 4.100 Å while the distance between two pairs of layers is 4.047 Å., The title compound, [Zn(C72H44N4O8)(C4H10N2)] or [Zn(TPBP)(pipz] (where TPBP and pipz are 5,10,15,20-tetra­kis­[4-(benzo­yloxy)phen­yl]porphyrinato and piperazine ligands respectively), features a distorted square-pyramidal coordin­ation geometry about the central ZnII atom. This central atom is chelated by the four N atoms of the porphyrinate anion and further coordinated by a nitro­gen atom of the piperazine axial ligand, which adopts a chair confirmation. The average Zn—N(pyrrole) bond length is 2.078 (7) Å and the Zn— N(pipz) bond length is 2.1274 (19) Å. The zinc cation is displaced by 0.4365 (4) Å from the N4C20 mean plane of the porphyrinate anion toward the piperazine axial ligand. This porphyrinate macrocycle exhibits major saddle and moderate ruffling deformations. In the crystal, the supra­molecular structure is made by parallel pairs of layers along (100), with an inter­layer distance of 4.100 Å while the distance between two pairs of layers is 4.047 Å. A region of electron density was treated with the SQUEEZE [Spek (2015 ▸). Acta Cryst. C71, 9–18] procedure in PLATON following unsuccessful attempts to model it as being part of disordered n-hexane solvent and water mol­ecules. The given chemical formula and other crystal data do not take into account these solvent mol­ecules.

In the crystal, the ZnII cation is chelated by four pyrrole-N atoms of the porphyrinate anion and coordinated by a pyridyl-N atom of the 4-cyano­pyridine axial ligand in a distorted square-pyramidal geometry. The non-coordinating 4-cyano­pyridine mol­ecule is disordered over two positions in the supra­molecular channel formed by complex mol­ecules., 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).

The [2 + 2] photodimerization of 2,6-difluorocinnamic acid was gradually induced in crystals by UV radiation at 0.5, 1.1 and 2.1 GPa. The crystal and molecular structures were determined before the photochemical reaction and for many of its steps. For the pure monomer structures, the following parameters were analyzed in order to gain knowledge of the influence of pressure on the reaction environment: (a) the volume of free space, (b) the geometry of close intermolecular interactions, including hydrogen bonds and (c) the geometry of intermolecular reactivity parameters. The following structural changes brought about by the [2 + 2] photodimerization at high pressure were monitored step-by-step: (a) the cell parameters and the cell volume, (b) the content of the monomer and the dimer, (c) the distance between the reactive carbon atoms in adjacent monomer molecules and (d) the geometry of mutual orientation of molecules in the crystals. The rate of the [2 + 2] photodimerization of 2,6-difluorocinnamic acid increased as follows: 0.1 MPa < 0.5 GPa < 1.1 GPa ≤ 2.1 GPa. This was rationalized by the decrease in the volume of free space columns protecting the intermolecular geometry suitable for the reaction and by the decrease of the distance between the reactive carbon atoms of adjacent monomer molecules.

New complexes of Pd(II) with 7-azaindole (7AI), trans-[PdCl2(7AI)2] (1) and 1⋅DMF were synthesized. A single crystal X-ray diffraction of 1⋅DMF has shown that the complex crystallizes in the monoclinic system (space group P21/n with a = 7.65743 (13), b = 11.9426 (2), c = 13.3870 (2) A, β = 91.2583 (16)°, V = 1223.94 (3) (A3) and Z = 2). Palladium is bound to two pyridine nitrogen atoms of the 7AI ligands and to two chloride ions, in a square-planar trans arrangement. The FT-Raman and infrared spectra of 1 were recorded in the 3600–50 cm−1 range. The molecular structure of 1 was confirmed by elemental analysis and vibrational spectra. Comprehensive theoretical calculations (including the optimized structural parameters, the HOMO–LUMO energy gap, harmonic frequencies and vibrational intensities) were performed for 1 by using the B3LYP and PBE0 density functional methods with the 6-311G++(d,p)/LanL2DZ basis sets. A natural bond orbital (NBO) analysis was carried out. A detailed assignment of the experimental vibrational spectra was performed on the basis of the potential energy distribution (PED). The Pd–Cl stretching vibrations were assigned to bands at 339 (IR) and 292 cm−1 (Raman). The bands at 273 and 260 cm−1 (IR) and 195 cm−1 (Raman) correspond to the Pd–N(pyridine) stretching vibrations. The unequivocal assignment of these modes is necessary for the structural characterization of other Pd(II) and Pt(II) complexes with the pyridine-based ligands, by using vibrational spectroscopy.

The results from monitoring structural changes brought about by the [2 + 2] photodimerization of 2-benzyl-5-benzylidenecyclopentanone (BBCP) in crystals at high pressure were presented. This is one of the two first examples of such studies for an intermolecular reaction. The influence of pressure of 0.5 GPa on the extent of changes caused by the photochemical reaction in the cell volume, in the molecular orientation and in the distance between reactive atoms is the same or similar to for 0.1 MPa of pressure, however, the character of the changes in the above-mentioned distance is different. The reason for the observed close similarity between the reaction path at 0.1 MPa and 0.5 GPa is a very good fit for dimer molecules to the crystal lattice of the monomer. The influence of high pressure itself on (a) the volume of the unit cell, (b) the volume of the free space in the unit cell, (c) the geometry of intermolecular interactions and (d) the distance between directly reacting atoms of two adjacent molecules was also described. The reaction rate is greater at 0.7 GPa than at 0.5 GPa; however, the difference is small. This was explained by the consistency between structural changes that came about by the photochemical reaction and by high pressure.

5-Bromo-7-azaindole (5Br7AI) may act as the carrier ligand for platinum(II), in new anticancer agent, cis -[PtCl 2 (5Br7AI) 2 ]. The crystal and molecular structure of the title molecule has been reinvestigated by a single crystal X-ray diffraction. The FT-IR and FT-Raman spectra of (5Br7AI) and its N-deuterated derivative have been recorded. The molecular structures of monomer and dimer, natural charges on atoms and theoretical vibrational spectra have been studied by density functional B3LYP method using 6-311++G(d,p) basis set. The results have shown that in the crystal, a pair of 5Br7AI molecules forms a centrosymmetric dimer linked by the moderately strong, dual and nearly linear N–H⋅⋅⋅N hydrogen bonds between the pyrrole and pyridine rings. The optimized geometry of the (5Br7AI) 2 dimer and the calculated spectra show very good agreement with the experiment. Detailed vibrational assignments for all the species have been made on the basis of the calculated potential energy distributions (PEDs). It is concluded that a complicated spectral features of the NH (ND) stretching absorption bands are due to multiple Fermi resonances, and they are characteristic for the doubly hydrogen bonded N–H⋅⋅⋅N dimers of 7-azaindole and its halogeno derivatives.

The results of the monitoring of the [4 + 4] photocycloaddition reaction path in single crystals of bi(anthracene-9,10-dimethylene) at high pressure are presented. The crystal structures for several steps of the phototransformation at 0.3 GPa and 1.0 GPa were determined and analysed. The applied high pressure did not halt the photochemical reaction and almost 100% of the product molecules were obtained, although the reaction was very slowly reversible similarly to that of ambient conditions. During the crystal phototransformation the intramolecular geometry, molecular orientation and intermolecular interactions of the reactant changed more and more towards the values observed for the product. The initial increase in the unit cell volume brought about by the photochemical reaction was diminished by high pressure. High pressure itself did not significantly influence the intramolecular geometry of the reactant and product molecules, but it influenced the intermolecular interactions.

The structure of the new polymorph II of 4-chlorocinnamic acid was presented and compared with the structure of polymorph I. Molecules in both polymorphs formed stacks, but the mutual arrangement of the stacks was different in both cases. The values of the intermolecular geometrical parameters indicated that both polymorphs should undergo the [2 + 2] photodimerization. The results of the studies of this photochemical reaction for polymorph II were analyzed. The crystal structures were determined at 0.1 MPa, 0.2 GPa, 0.5 GPa and 2.0 GPa before the reaction and at 0.1 MPa and 0.5 GPa for the partly reacted crystals until ca. 20% reaction progress. This allowed for the monitoring of the photo-induced structural changes and the influence of high pressure on them. High pressure was able to significantly hinder the increase of the unit cell volume and the changes in intermolecular interactions caused by the reaction. The observed changes in the unit cell volume were compared with the data for 2,6- and 2,5-difluorocinnamic acids featuring stack arrangement and 4-chlorocinnamide in which molecules were arranged in centrosymmetric pairs. The differences were explained in terms of the amount of free space in the unit cells. The distance between two neighbouring monomers was constant during the photochemical reaction and the same was true for other cinnamic acids of stack arrangement, but opposite to the compounds where molecules formed centrosymmetric pairs.

We studied the photochemical reactivity of salts of 4-(2,4,6-triisopropylbenzoyl)benzoic acid with propane-1,2-diamine (1), methanamine (2), cyclohexanamine (3), and morpholine (4), for compounds (1), (3), and (4) at 0.1 MPa and for compounds (1) and (2) at 1.3 GPa and 1.0 GPa, respectively. The changes in the values of the unit cell parameters after UV irradiation and the values of the intramolecular geometrical parameters indicated the possibility of the occurrence of the Norrish&ndash, Yang reaction in the case of all the compounds. The analysis of the intramolecular geometry and free spaces revealed which o-isopropyl group takes part in the reaction. For (1), the same o-isopropyl group should be reactive at ambient and high pressures. In the case of (2), high pressure caused the phase transition from the space group I2/a with one molecule in the asymmetric unit cell to the space group P1&macr, with two asymmetric molecules. The analysis of voids indicated that the Norrish&ndash, Yang reaction is less probable for one of the two molecules. For the other molecule, the intramolecular geometrical parameters showed that except for the Norrish&ndash, Yang reaction, the concurrent reaction leading to the formation of a five-membered ring can also proceed. In (3), both o-isopropyl groups are able to react, however, the bigger volume of a void near 2-isopropyl may be the factor determining the reactivity. For (4), only one o-isopropyl should be reactive.

Contrary to the known 4-(2,4,6-triisopropylbenzoyl)benzoate salts, di-μ-aqua-bis[tetraaquasodium(I)] bis[4-(2,4,6-triisopropylbenzoyl)benzoate] dihydrate, [Na2(H2O)10](C23H27O3)2·2H2O, (1), does not undergo a photochemical Norrish–Yang reaction in the crystalline state. In order to explain this photochemical inactivity, the intermolecular interactions were analyzed by means of the Hirshfeld surface and intramolecular geometrical parameters describing the possibility of a Norrish–Yang reaction were calculated. The reasons for the behaviour of the title salt are similar crystalline environments for both theo-isopropyl groups in the anion, resulting in similar geometrical parameters and orientations, and that these interaction distances differ significantly from those found in salts where the photochemical reaction occurs.

3-Chloro-7-azaindole (3Cl7AI) is the carrier ligand in a new anticancer platinum(II) agent cis-[PtCl2(3Cl7AI)2]. In this work 3Cl7AI has been studied by a single crystal X-ray diffraction, infrared and Raman spectroscopy and density functional calculations. The compound crystallizes in the monoclinic system, space group P21/n, with a = 12.3438(3), b = 3.85964(11), c = 14.4698(4) A, β = 100.739(2)°, V = 677.31(3) A3 and Z = 4. In the crystal, a pair of 3Cl7AI molecules forms a centrosymmetric dimer linked by the moderately strong dual N–H⋯N hydrogen bonds. The nitrogen atom in the pyrrole ring acts as the proton donor, while the nitrogen atom in the pyridine ring is the proton acceptor. The FT-IR and FT-Raman spectra (3500–60 cm−1) have been recorded. The theoretical studies on the molecular structures and vibrational spectra of the monomeric and dimeric forms of 3Cl7AI and its N-deuterated derivative were performed using the B3LYP method with 6-311++G(d,p) basis set. The theoretically predicted Raman spectrum for the dimer shows very good agreement with experiment. Detailed vibrational assignments for the two isotopomers have been made on the basis of the calculated potential energy distributions (PEDs). The dual N–H⋯N hydrogen bonds in 3Cl7AI dimer are characterized by a very broad and complicated structure of the absorption band between 3300 and 2500 cm−1, which is caused by multiple Fermi resonances between the N–H stretching vibration and various combinations bands.

Studies have revealed how pressure influences the path of one photochemical reaction in crystals. The single-crystal-to-single-crystal Norrish–Yang reaction of 4-(2,4,6-triisopropylbenzoyl)benzoate benzylammonium, compound 1, was studied at high pressures of 0.3 and 0.9 GPa. X-ray structure analysis was used in order to monitor the kinetics of the reaction and the structural changes induced by UV radiation and pressure. The reaction rate is lower at higher pressure: the rate constants are 5.3 × 10−5 s−1 and 4.3 × 10−6 s−1 at 0.3 and 0.9 GPa, respectively. This was rationalized by: (a) the decrease in the size of voids near the reaction centre and in the unit cell with pressure, (b) the increase of intermolecular interactions in which the photoreactive o-isopropyl group takes part along with pressure and (c) the structural changes brought about by the photochemical reaction itself, for example, the increase of the unit cell volume. Pressure significantly reduced these structural changes and even halted some of them.

The structures of 1-(4-methylphenyl)-3-(2-thienyl)prop-2-en-1-one, (I), 1-(5-bromo-2-hydroxyphenyl)-3-(2-furyl)prop-2-en-1-one, (II), and 1-(3-furyl)-3-[3-(trifluoromethyl)phenyl]prop-2-en-1-one, (III), were determined in ambient and high pressure conditions. The values of the intermolecular geometrical parameters describing possibilities of execution of [2+2] photodimerization were calculated and analysed. In the case of ambient pressure, for (I) they are close to the border valid for photoreactive compounds and for (II) and (III) they exclude the photochemical reaction in crystals. High pressure hardly changed the mutual orientation of adjacent molecules and largely the distance between them: in the case of (I), the distance was far below limits for compounds undergoing [2+2] photodimerization. The volume of free space was calculated for the studied compounds for different values of pressure and analysed in the context of possibilities of the [2+2] photodimerization.

The reaction between benzyl amines, triethyl orthoformate, and diethyl phosphite affords either bisphosphonic (compound 1) or N-benzylaminobenzylphosphonic (compound 2) acid depending on the reaction conditions. The final output of the reaction can be manipulated by the choice of reaction conditions, particularly the molar ratio of substrates.

The main aim of the studies in this paper is to gain knowledge on the path of structural transformations resulting from the photocyclization in 2-tert-butylphenylphenylmethanone crystals at low and high pressures and also to carry out a comparative analysis of the results at different pressures. This work is the first example of these types of studies in scientific literature. We determined the structure of: pure reactant crystals, i.e. only containing reactant molecules, at 0.1 MPa, 0.55 GPa, 1.27 GPa and 1.50 GPa; pure product crystals, i.e. only containing product molecules, at 0.55 GPa and 1.27 GPa; and partly reacted crystals (ten structures), i.e. containing both reactant and product molecules in various proportions to each other, at 0.1 MPa (two structures), 0.55 GPa (three structures), 1.27 GPa (three structures) and 1.50 GPa (two structures). The studies have shown that (a) there is no phase transition when an increase in pressure is imposed onto the crystals, (b) the unit cell parameters change non-linearly with an increase in pressure, (c) the photochemical reaction was conducted in a homogeneous manner in the examined crystals, (d) the reaction brings about different modes of changes in the unit cell parameters at different pressures (e) the reaction proceeds faster at the end rather than at the beginning regardless of the pressure imposed onto the crystals.

The Norrish–Yang reaction was conducted in crystals of benzylammonium, pyrrolidinium and ammonium 4-(2,4,6-triisopropylbenzoyl)benzoates (1–3). The crystal structures of 1–3, six structures of the partly reacted crystals of these compounds and the structure of the pure product crystal for 1 were determined. The content of the product in the partly reacted crystals allowed to calculate the values of the rate constants and the orders of the reaction for 1 and 3 by the JMAK model. The results indicated that the Norrish–Yang reaction proceeded homogeneously for 3 and according to a hybrid mechanism for 1. The rate constant was much higher for 3 than for 1. The differences in the reactivity were explained by the intramolecular geometrical parameters and intermolecular interactions mapped onto the Hirshfeld surfaces. The results showed that it is possible to largely change reactivity of the one organic species, even several hundred times, by modifying the crystal lattice in which it is embedded.