Desolvaton of Zinc(II)tetra-tert-butylphthalocyanine Crystal Solvates as Probed by Thermogravimetry

Kinetic analysis of the thermal destruction of complexes of zinc(II)tetra-tert-butylphthalocyanine Zn(t-Bu)₄Pc with organic solvent molecules has been carried out. For ligands having high ionization potentials, long refluxing of solution is required for preparing biligand complexes. For molecular ligands whose ionization potentials do not exceed 9.2 eV, the composition of complexes with Zn(t-Bu)₄Pc is independent of the preparation parameters. The destruction of the Zn(t-Bu)₄Pc complexes with n-propylamine, diethylaniline, piperidine (1: 1, cold synthesis), diethylamine, morpholine, quinoline, or cyclopentanone (1: 2, hot synthesis; 1: 2, cold synthesis) obeys fist-order equations; for complexes with pyridine, 1,4-dioxane, DMF, cyclopentanone (1: 1, hot synthesis), 3-dimethylaminopropionitrile, or piperidine (1: 2, hot synthesis), destruction obeys second-order equations. The activation energies of thermal destruction for the first group of molecular complexes fall in the range from 89 to 370 kJ/mol; the rate-controlling stage is nucleation and growth. For the second group, the activation energies fall in the range from 160 to 640 kJ/mol; the rate-controlling stage is a chemical reaction.     

(4‐Aminopyridine‐κN1)(phthalocyaninato‐κ4N)zinc(II) tetrahydrofuran disolvate

The title compound, [Zn(C₃₂H₁₆N₈)(C₅H₆N₂)]·2C₄H₈O, consists of one (phthalocyaninato)zinc (ZnPc) unit, a coordinated 4‐aminopyridine (4‐ap) molecule and two tetrahydrofuran (THF) solvent molecules. The central Zn atom is (4+1)‐coordinated by four isoindole N atoms of the Pc core and by the pyridine N atom of 4‐aminopyridine. The Zn atom is displaced by 0.4464 (8) Å from the isoindole N₄ plane towards the pyridine N atom. The crystal structure is stabilized by intermolecular amine–phthalocyaninate N—H...N hydrogen bonds and π–π interactions between the aggregated Pc rings, which form molecular layers, and by weak van der Waals interactions between the layers. As well as hindering the aggregation of ZnPc molecules by occupying an axial position, the amino group will add new interactions which will favor applications of ZnPc, for example, as a sensitizer of photodynamic therapy.     

Complexes of pyridine and quinoline N-oxides with boron trifluoride: the <Superscript>1</Superscript>H NMR study

The formation of complexes of pyridine and quinoline N-oxides with BF₃ was studied by ¹H NMR method. It was shown that the molecular complexes obtained are either individual isomers or a mixture of stereoisomers, whose structures are determined by both electronic and steric properties of substituents in a heterocycle. The type of hybridization (sp3 or sp2) of the O atom of the N-oxide group in the above adducts was assumed to be specified also by the above factors.     

Highly active Pd(II) catalysts with pyridylbenzoimidazole ligands for the Heck reaction

The air-, and thermo-stable palladium(II) complexes C1-C10 are prepared by the reaction of PdCl₂(CH₃CN)₂ with pyridylbenzoimidazole. With various substituents on the pyridine ring, palladium atom was coordinated by two pyridylbenzoimidazole molecules via nitrogen atoms of benzoimidazole. The structure of complexes C3, C4, C6, and C7 has been confirmed by X-ray diffraction analysis. Without substituents on the pyridine ring, palladium atom was directly coordinated with two nitrogen atoms of pyridine and benzoimidazole nitrogen via intramolecular chelation (C10). These complexes performed the Heck olefination of aryl bromides in a good to high yield under phosphine-free conditions.     

Thermal and spectral analyses of complexes of zinc(II)tetra-tertbutylphthalocyanine with amines

Spectral and thermochemical studies of complexes of zinc(II)tetra-tertbutylphthalocyanine (Zn(t-Bu)₄Pc) with some amines have been carried out. Spectral effects of the complex formation of the metallophthalocyanine with amines have been established. It has been found that an ability of Zn(t-Bu)₄Pc to coordinate amines depends on both their nature and conditions of preparation. Similarity of the crystal structures of biligand and monoligand of Zn(t-Bu)₄Pc complexes to individual β- and α-polymorphs of Zn(t-Bu)₄Pc, respectively is proved by IR spectroscopy and X-ray diffraction method.     

Interaction of porphyrins with adenine and adenosine complexes. Effect of a metal nature

Reactions of complex formation of 5,10,15,20-tetraphenylporphine (H₂TPP) and tetra-tert-butylphthalocyanine (H₂(t-Bu)₄Pc) with adenine and adenosine complexes of d-metals in DMSO and ethanol are studied. It was found that H₂TPP reacts with Cu(II) and Hg(II) adeninates and adenosinates in DMSO, but does not react with Zn(II), Co(II), and Cd(II) adeninates and adenosinates (with both bridging and monodentate type of the ligand coordination). H₂(t-Bu)₄Pc enters the complex formation reaction with adeninates and adenosinates of all studied metals in DMSO at almost equal rates. The states of adenine and adenosine complexes of different d-metals in DMSO and ethanol are proposed on the basis of kinetic data obtained.     

Synthesis,Structure, and Spectroscopic Properties of Octa(iso‐pentoxy)phthalocyaninatometal Complexes

A series of octa‐substituted metal phthalocyanines [MPc(OC₅H₁₁)₈] (M = Co, Ni, Cu, Zn, Pc = phthalocyaninato, (OC₅H₁₁)₈ = iso‐pentoxy) were obtained from condensation of iso‐pentoxy phthalonitrile in the presence of DBU in n‐pentanol. The compounds were characterized using elemental analysis, IR, and UV/Vis spectra. The crystal structures of all compounds except M = Zn were determined by X‐ray diffraction methods. It was found that the distortion of Pc skeleton come of not only the intra‐molecular steric congestion of bulky substituents, but also the slipped overlaps of the closest molecules. The relations of some bond lengths of the Pc's skeleton to the substituents and central metal atom, as well as the spectroscopic properties are discussed.     

Mass-spectrometric study of 4-azaphenanthrene derivatives

The mass spectra of 15 compounds of the 4-azaphenanthrene series and their deutero analogs with bulky R substituents (R=-CCPh, -CH=CHPh, CHBr-CHBrPh,-CH=CHC₆H₄OCH₃-p, -COOH, -COOC₂H₅, and -CONHNH₂) in the ortho position relative to the nitrogen atom were studied. An intense [M-H]⁺ ion peak, the appearance of which is evidently due to a process involving cyclization of the carbon atom of the side chain with the nitrogen atom, is formed in the fragmentation of the styryl derivatives. The fragmentation of the compounds with a methyl group in the ortho position relative to the styryl grouping is accompanied by the formation of an intense [M-Ph]⁺ ion peak. An ortho effect of the carboxyl and carbethoxy groups adjacent to the methyl substituent is observed in the mass spectra of the investigated compounds. The data obtained make it possible to establish the structures of bulky substituents in the ortho position relative to the ring nitrogen atom and the position of the methyl group in the pyridine ring of monomethylated azaphenahthrenes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 659–665, May, 1979.     

Preparation and structural characterization of organotin(IV) complexes with ligands containing a hetero {N} atom and a hydroxy group or hydroxy and carboxyl groups

Twenty-two n-butyltin(IV) and t-butyltin(IV) complexes of ligands containing an -OH (-CO) group or -OH and -COOH groups and an aromatic {N} donor atom were prepared by metathetical reactions. On the basis of the FT-IR and Mössbauer spectroscopic data, molecular structures were assigned to these compounds. The binding sites of the ligands were identified by means of FT-IR spectroscopic measurements, and it was found that in most cases the organotin(IV) moiety reacts with the phenolic form of these ligands. In the complexes with -OH and -COOH functions, the -COOH group is coordinated to the organotin(IV) centres in a monodentate manner. The ¹¹⁹Sn Mössbauer and the FT-IR studies support the formation of trigonal bipyramidal (TBP) and octahedral (O_h) molecular structures. Furthermore, X-ray diffraction analysis has been performed on the n-butyltin(IV)- and t-butyltin(IV)-8-quinol 8-olato-O,N single crystals. The hexacoordinated tin centres exhibit cis-octahedral geometry in both complexes.     

Methyloxy Substituted Heteroleptic Bis(phthalocyaninato) Yttrium Complexes: Density Functional Calculations

The effects of alkyloxy substituents attached to one phthalocyanine ligand of three heteroleptic bis(phthalocyaninato) yttrium complexes Y(Pc)[Pc(α‐OCH₃)₄] ( 1 ), Y(Pc)[Pc(α‐OCH₃)₈] ( 2 ), and Y(Pc)[Pc(β‐OCH₃)₈] ( 3 ), as well as their reduction products {Y(Pc)[Pc(α‐OCH₃)₄]}^? ( 4 ), {Y(Pc)[Pc(α‐OCH₃)₈]}^? ( 5 ), and {Y(Pc)[Pc(β‐OCH₃)₈]}^? ( 6 ) [H₂Pc(α‐OCH₃)₄=1,8,15,22‐tetrakis(methyloxy)phthalocyanine; H₂Pc(α‐OCH₃)₈=1,4,8,11,15,18,22,25‐octakis(methyloxy)phthalocyanine; H₂Pc(β‐OCH₃)₈=2,3,9,10,16,17,23,24‐octakis(methyloxy)phthalocyanine] are studied by DFT calculations. Good consistency is found between the calculated results and experimental data for the electronic absorption, IR, and Raman spectra of 1 and 3 . Introduction of electron‐donating methyloxy groups on one phthalocyanine ring of the heteroleptic double‐deckers induces structural deformation in both phthalocyanine ligands, electron transfer between the two phthalocyanine rings, changes in orbital energy and composition, shift of electronic absorption bands, and different vibrational modes of the unsubstituted and substituted phthalocyanine ligands in the IR and Raman spectra in comparison with the unsubstituted homoleptic counterpart Y(Pc)₂. The calculations reveal that incorporation of methyloxy substituents at the nonperipheral positions has greater influence on the structure and spectroscopic properties of bis(phthalocyaninato) yttrium double‐deckers than at the peripheral positions, which increases with increasing number of substituents. Nevertheless, the substituent effect of alkyloxy substituents at one phthalocyanine ligand of the double‐decker on the unsubstituted phthalocyanine ring and on the whole molecule and the importance of the position and number of alkyloxy substituents are discussed. In addition, the effect of reducing 1 – 3 to 4 – 6 on the structure and spectroscopic properties of the bis(phthalocyaninato) yttrium compounds is also discussed. This systemic DFT study is not only useful for understanding the structure and spectroscopic properties of bis(phthalocyaninato) rare earth metal complexes but also helpful in designing and preparing double‐deckers with tunable structure and properties.     

Tetrameric complexes of germanium(IV) and cobalt(II), Nickel(II), or Zinc(II) with 1,3-Diamino-2-propanol-tetraacertic acid: crystal and molecular structures of [(OH)2Ge2(μ-Hpdta)2Zn2(H2O)4] · 12H2O

Heteronuclear germanium(IV) and Zn(II) (Co(II), Ni(II)) complexes with 1,3-diamino-2-propanol-tetraacetic acid (H₅Hpdta) were synthesized. The compounds were characterized by elemental analysis, thermogravimetry, and IR spectroscopy. X-ray diffraction analysis of the crystals of [(OH)₂Ge₂(??-Hpdta)₂Zn₂(H₂O)₄] · 12H₂O (I) was performed. The crystals are tetragonal, a = 15.2022(9)?, c = 20.932(3) ?, V = 4837.5(7) ?³, Z = 4, space group P4₃, R1 = 0.0449 over 11399 reflections with I > 2??(I). The structural units of the crystal are tetrametric complex molecules [(OH)₂Ge₂(??-Hpdta)₂Zn₂(H₂O)₄] and water molecules of crystallization. The tetramer is composed of two similar neutral dimeric molecules [(OH)Ge(??-Hpdta)Zn(H₂O)₂]. The germanium and zinc atoms in the dimer are linked by the bridging oxygen atom of the deprotonated isopropanol group of the Hpdta^5? ligand (average Ge-O, 1.844(2)?; Zn-O, 2.192(3)?). The coordination sphere of the Ge and Zn atoms contains also one nitrogen atom (average Ge-N, 2.074(4)?; Zn-N, 2.156(3)?), four oxygen atoms belonging to four acetate branches of the octadentate Hpdta^5? ligands including two carboxyl O atoms for each Ge atom (average Ge-O, 1.912(3)?) and two carbonyl O atoms for each Zn (average Zn-O, 2.065(3)?). The coordination polyhedron of each Ge atom is completed to a distorted octahedron by the oxygen atom of the terminal hydroxy group (average Ge-O, 1.772(2)?) and the carboxyl oxygen atom of the bridging acetate branch (average Ge-O, 1.926(3)?) coordinated through carbonyl oxygen to Zn atom (average Zn-O, 2.148(3)?) of the second dimeric molecule. The distorted octahedron around each Zn atom is completed by oxygens of two water molecules at substantially different distances (average Zn-O, 1.984(3) and 2.100(3)?). The structural units are combined by O-H??O hydrogen bonds to form a framework.     

Synthese und Koordinationsverhalten neuer Schiffscher Basen aus 3‐Formylacetylaceton und natürlichen L‐Aminosäuren

Three novel chiral Schiff Base ligands (H₂L) were prepared from the condensation reaction of 3‐formyl acetylacetone with the amino acids L ‐alanine, L ‐phenylalanine, and L ‐threonine. X‐ray single crystal analyses revealed that the Schiff Base compounds exist as enamine tautomers in the solid state. The molecular structure of the compounds is stabilized by an intramolecular hydrogen bridge between the enamine NH function and a carbonyl oxygen atom of the pentandione residue. Treatment of the ligands H₂L with copper(II) actetate in the presence of pyridine led to the formation of copper complexes [CuL(py)]. In each of the complexes the copper atoms adopt a distorted square‐pyramidal coordination. Three of the basal coordination sites are occupied by the doubly deprotonated Schiff Bases L^2– which act as tridentate chelating O, N, O‐ligands. The remaining coordination sites are occupied by a pyridine ligand at the base and a carboxyl oxygen atom of a neighboring complex at the apical position. The latter coordination is responsible for a catenation of the complexes in the solid state.     

Synthesis,spectroscopic characterization,X-ray structure and magnetic properties of [Cu(hmquin-7-COOH)2(MeOH)] complex

The reaction of copper(II) chloride dihydrate and 8-hydroxy-2-methylquinoline-7-carboxylic acid (Hhmquin-7-COOH) leads to [Cu(hmquin-7-COOH)₂(MeOH)]. The compound has been studied by IR, UV–Vis, EPR spectroscopy and X-ray crystallography. X-ray studies confirm bidentate coordination mode of the hmquin-7-COOH anions via the pyridine nitrogen atom and deprotonated hydroxyl group. The COOH groups of the hmquin-7-COOH ligands are potentially available for further conjugation. The title complex has been additionally studied by magnetic measurement. The TDDFT/PCM calculations have been employed to discuss the electronic spectrum of [Cu(hmquin-7-COOH)₂(MeOH)] in more detail.     

First and second coordination spheres in divalent metal compounds containing pyridine and 4,6-dimethyl-1,2,3-triazolo[4,5-d]pyrimidin-5,7-dione

The interaction in aqueous media of 4,6-dimethyl-1,2,3-triazolo[4,5-d]pyrimidin-5,7-dione (1,3-dimethyl-8-azaxanthine, Hdmax) with salts of divalent Mn, Co, Ni, Cu, Zn and Cd in the presence of an excess of pyridine (py) leads to the formation of crystalline solids, the structures of which have been solved by single crystal X-ray diffraction. The solids containing Mn, Co, Zn and Cd are isostructural, presenting a formulation trans-[M(H₂O)₄(py)₂](dmax)₂, with the heterocycle in the anionic form and not directly linked to the metal atom. The H-bond network of these complexes include a tape superstructure topologically identical to that present in the previously reported hexa-aqua salts of the dmax⁻ anion, which may be regarded as a case of molecular recognition between dmax⁻ and the square planar [M(H₂O)₄] subunit. On the other hand, for Ni and Cu the triazolopyrimidine ligand is directly coordinated to the metal through the external imidazole nitrogen atom (N2) generating the compounds [M(dmax)₂(H₂O)₂(py)₂] · 2H₂O, which display a less tight H-bonding network.     

Structural effect of the competition of 4-picoline and water molecules to form complexes with Be,Mg and Zn phthalocyanines

The BePc(4-Mepy), MgPc(4-Mepy)₂ were recrystallised from wet 4-picoline and the aqua M((II) phthalocyaninato complexes, BePcH₂O · (4-Mepy) (Ia), (MgPcH₂O · (4-Mepy))₂ (IIa) and (MgPcH₂O · (4-Mepy)₂) · (4-Mepy) (IIb), have been obtained. Recrystallisation of ZnPc(4-Mepy) in wet 4-picoline yields the β-ZnPc in microcrystalline form. The Ia, IIa and IIb complexes were obtained in crystalline form. The composition of the Mg complexes (IIa and IIb) depends on the crystallisation temperature. The BePcH₂O · (4-Mepy) compound crystallises in the centrosymmetric space group of the triclinic system, while both Mg complexes crystallise in the P2₁/n space group of the monoclinic system. In all crystals the central M(II) atom (Be and Mg) is 4 + 1 coordinated, equatorially by four N-isoindole atoms of Pc macrocycle and axially by O atom of water molecule. Interaction of the central M atom of MgPc with axially ligated water molecule leads to the saucer-shape of the Pc ring and deviates the central M(II) atom from the N₄-isondole plane by 0.308(2), 0.482(2) and 0.537(2) Å in Ia, IIa and IIb, respectively. The molecules in the Ia and IIa crystals are linked together by a pair of O–H?N hydrogen bonds between the H atom of water molecule and the azamethine N atom of the other Pc into a dimeric structure, and the 4-picoline molecules are linked to the (MPcH₂O)₂ dimeric structure. In IIb crystal the MgPcH₂O molecule is linked by O–H?N hydrogen bonds with two 4-picoline molecules, while the third 4-picoline molecule interacts only by the van der Waals forces. The O–H?N hydrogen bonding system and the π–π interactions between the aromatic Pc macrocyles are the key for the molecular arrangement and stabilisation of the structure. The stability of the solid-state complexes was analysed by thermogravimetric measurements. Only the solid-state spectrum of IIa complex exhibits an intense near IR absorption band. The spectra of IIa and IIb in solution are identical, the Q band is blue shifted in O-donor solvents comparing with the spectrum in N-donor solvents.     

Substituent effect in para substituted Cr(CO)5-pyridine complexes

Systematic studies on the substituent effect in para substituted Cr(CO)₅-pyridine complexes have been carried out on the basis of DFT quantum-chemical calculations. Ten simple and mostly common substituents were chosen in order to analyze possibly the largest spectrum of substituent effects. The following substituents were taken into consideration: NO, NO₂, CN, CHO, F, H, CH₃, OCH₃, OH and NH₂. Additionally, the Cr-N and Cr-C bonds were characterized on the basis of Atoms in Molecules topological analysis of electron density. It has been found that the substituents in position 4 of the pyridine ring influence the Cr-N bond of Cr(CO)₅-pyridine complex in a systematic manner, as a result of with, the pyridine moiety has a diversified ability of participating in the interaction with the Cr atom of Cr(CO)₅ moiety. It has also been found, that the electron withdrawing substituents additionally stabilize the Cr-N bond, whereas the electron donating ones weaken it. The substituent effect mainly affects the π-component of the Cr-N bond. This effect proceeds in the whole Cr-pyridine-R moiety, and it is additionally reflected in the corresponding changes in metal-carbonyl bonds, particularly the trans Cr-CO bond.     

Complexes of 1-(<Emphasis Type="Italic">N</Emphasis>-heterylmethyl)silatranes with metal chlorides

The hitherto unknown complexes of 1-(N-heterylmethyl)silatranes HetCH₂Si(OCH₂CH₂)₃N (Het is imidazolyl, 3,5-dimethylpyrazolyl, 1,2,4-triazolyl, benzimidazolyl, 1,2,3-benzotriazolyl) with chlorides of divalent metals MCl₂ (M = Cu, Zn, Cd, Co, Pd) of 1:1 composition are synthesized. The ligands are coordinated to the metal ion by the pyridine nitrogen atom of the azole heterocycle.     

Synthesis and crystal structure of pyridine and methanol coordinated α-octabutyloxyphthalocyaninatocobalt (II)

Crystal structure of pyridine and methanol axially coordinated 1,4,8,11,15,18,22,25-octabutyloxyphthalocyaninatocobalt(II)(viz. α-octabutyloxyphthalocyaninatocobalt) [(n-BuO)₈Pc]. Co(Py)(MeOH) (1) was determined by X-ray diffraction methods. Crystal data: monoclinic, space group P2₁/n, Z = 4, a = 1.06482(4), b = 3.5487(2), c = 1.79428(9) nm, β=103.246(2)°, V = 6.5792(5) nm³, μ = 0.325 mm^-1. The result shows that the ring skeleton of 1 maintains planar conformation, which is similar to that of unsubstituted phthalocyanine but is remarkably different from the saddle shape conformation of 1,4,8,11,15,18,22,25-octabutyloxyphthalocyaninatocopper (II) [(n-BuO)₈Pc]Cu(2), which has no axial coordination. In the structure of 1, the substituents butyloxy groups of 1 somewhat deviate from the ring plane, while pyridine and methanol are coordinated to the center atom Co from opposite sides of the ring plane. In addition, all molecules are stacked along axis a to form one-dimensional molecule chain, the neighboring molecules in the chain overlap to some extent with a benzene ring and a distance of 0.3565 nm.     

Synthesis and characterization of zinc(II), copper(II) and cadmium(II) coordination polymers with tetrachloroterephthalate-based ligands

Three complexes, namely Zn(BDC-Cl₄)(py)₃ (1), Cu(BDC-Cl₄)(py)₃ (2) and Cd(BDC-Cl₄)(py)₃ (3) (BDC-Cl₄ = 2,3,5,6-tetrachloro-1,4-benzenedicarboxylate, py = pyridine) have been synthesized. Complexes (1) and (2) have been obtained using solvothermal methods. Both have a five-coordinate geometry with two bridging monodentate tetrachloroterephthalate ligands and three pyridine ligands coordinated to the Zn(II) or Cu(II) atom. The tetrachloroterephthalate ligands bridge the adjacent Zn(II) or Cu(II) centers, giving zigzag chains. Complex (3) has also been crystallized, each Cd(II) atom is six-coordinated to three carboxylate oxygen atoms and three pyridyl nitrogen atoms. Two types of tetrachloroterephthalate ligand, featuring monodentate and bidentate carboxylates, connect the Cd(II) centers to form zigzag chains. All three complexes have been subjected to thermogravimetric analysis.     

The metal complexes of amino acids and their N-substituted derivatives—VI. The physical properties,i.r. spectra and normal coordinate analysis of bivalent metal complexes with dl-threonine

Complexes of five bivalent metals with dl-threonine have been prepared and characterized by means of i.r. absorption, powder diffuse reflection, and electronic spectra, X-ray diffraction and magnetic susceptibility. The complexes appear to be of three distinct types. The first type includes ML₂·nH₂O (M = Ni, Cu, Zn; L = dl-threoninato anion), in which the ligand chelates metal ions through the nitrogen atom and the oxygen atom of the carboxylato group. Three species of copper(II) complexes have been prepared. They seem to be two trans forms and one cis form. MnCl₂(HL)₄·H₂O is a second type in which the metal is coordinated through the oxygen atom of the carboxyl group and chloride ions, but is not coordinated through the nitrogen atom. 2CdCl₂·HL·HCl·2H₂O is a third type, in which the metal is coordinated through only chloride ions. In order to assign the observed frequencies of i.r. absorption spectra in detail, a normal coordinate analysis has been accomplished for the complexes of the first type as a 33-body problem. Copper(II) and zinc(II) complexes with l-threonine have been prepared for comparison.