Glycosylamines of 4,6-O-butylidene-alpha-D-glucopyranose: synthesis and characterization of glycosylamines, and the crystal structure of 4,6-O-butylidene-N-(o-chlorophenyl)-beta-D-glucopyranosylamine

A total of nine glycosylamines of 4,6-O-butylidene-alpha-D-glucopyranose were synthesized using primary amines having various groups in their ortho- or para-positions. Among these, six are monoglycosylamines, including one primary glycosylamine, and three are bis-glycosylamines. All these compounds were characterized by 1H, 1H-1H COSY, 1H-13C COSY and 13C NMR spectroscopy and FTIR spectra. The FAB mass spectra provided the molecular weights of the products by exhibiting the corresponding molecular ion peaks. The crystal structure of 4,6-O-butylidene-N-(o-chlorophenyl)-beta-D-glucopyranosylamine revealed the C-1 glycosylation, the beta-anomeric nature, and the 4C1 chair conformation of the saccharide unit in the product. In the lattice two types of dimers exist. While one type of dimer is formed through O-H...O type of interactions, the other type is formed via C-H...O type of interactions. In the direction of these C-H...O type of interactions, the dimeric units are connected to form a chain.     

Synthesis, characterization and the first crystal structure of the Zn(II) complex of 4,6-O-ethylidine-N-(2-hydroxybenzylidene)-beta-D-glucopyranosylamine.

4,6-O-Ethylidine-N-(2-hydroxybenzylidene)-beta-D-glucopyranosylamine (H(3)L(1)) and N-(5-bromo-2-hydroxybenzylidene-4,6-O-ethylidine-beta-D-glucopyranosylamine (H(3)L(2)) molecules possessing a single bond C-1 single bond N double bond C(H) single bond moiety for metal-ion binding were synthesized by condensing the 4,6-O-ethylidene-beta-D-glucopyranosylamine with salicylaldehyde or 5-bromosalicylaldehyde. Complexes of these ligands with Zn(II) were isolated and characterized using elemental analysis, FTIR, UV-Vis absorption, NMR spectroscopic and FAB mass spectrometric techniques. The structure of the Zn(II) complex derived from H(3)L(1) was established for the first time by a single-crystal X-ray diffraction study. The anomeric nature of the saccharide moiety was established based on (1)H NMR studies and was confirmed by the crystal structure. Further, the structure and binding aspects of the ligand, and the coordination features of this in its Zn(II) complex were derived from the corresponding crystal structure.     

Crystal structure of 4,6-O-ethylidene-N-(2-hydroxybenzylidene)-beta-D-glucopyranosylamine.

4,6-O-Ethylidene-N-(2-hydroxybenzylidene)-beta-D-glucopyranosylamine was synthesized and characterized using analytical, spectral and single-crystal X-ray diffraction methods. The anomeric nature of the saccharide moiety was proposed based on 1H NMR studies and was confirmed by the crystal structure. The lattice structure of this compound was compared with that of its analogues.     

Synthesis, spectroscopic characterization, and crystal structures of two chlorodiorganotin(IV) 4-(2-methoxyphenyl)piperazine-1-carbodithioates

Two chlorodiorganotin(IV) complexes of 4-(2-methoxyphenyl)piperazine-1-carbodithioate (MPPDA) have been synthesized by 1:1 mole-ratio reactions of the parent acid (MPPDAH) with Me₂SnCl₂ or Et₂SnCl₂ in dry methanol. The products have been characterized by Raman and multinuclear NMR (¹H, ¹³C and ¹¹⁹Sn) spectroscopy, elemental analysis, and mass spectrometry. Single-crystal X-ray diffraction studies indicate that both complexes have distorted trigonal bipyramidal geometries around the central Sn atom.     

Synthesis, characterization, and crystal structures of hydrotris(2-mercapto-1-imidazolyl)borate-based zinc(II) and copper(I) complexes

The reaction of the tripod ligand hydrotris(2-mercapto-1-imidazolyl)borate Tm^xylyl with zinc(II) perchlorate in methanol afforded the mononuclear complex of the type [Tm^xylyl-Zn(mim^xylyl)]ClO₄ (1). Whereas under the same conditions, the reaction with copper(II) perchlorate gives rise to the simultaneous formation of the dinuclear copper(I) complex [Tm^xylylCu]₂ (2). The chemical formulae of the complexes have been characterized by elemental chemical analysis, IR-NMR spectroscopies, and single crystal X-ray methods. In complex 1, the zinc(II) atom displays a distorted tetrahedral environment. While in complex 2, the Tm^xylyl ligand bridges the two copper(I) atoms in an asymmetric manner with trigonal geometry. The inverted conformation of the ligand Tm^xylyl at the boron center, allows the B-H units to be directed towards the copper centers. The greater reactivity of the borohydride groups towards metal centers enhances the reduction of Cu(II) to Cu(I). The obtained kinetic results for the methylation reactions of 1 and 2 indicate that these bound thione complexes are less suitable to electrophilic attack than the thiolate ligand.     

Synthesis, characterization, crystal structures and DNA binding studies of nickel(II) hydrazone complexes

A series of octahedral and square-planar Ni(II) complexes have been synthesized from two different types of hydrazone ligands. The isolated complexes have been characterized by means of analytical and spectroscopic techniques. The structures of two of the complexes have been determined by single crystal X-ray diffraction study. The binding modes of the complexes with DNA and their ability to bind DNA have been investigated by UV-Vis absorption titration, ethidium bromide fluorescence displacement experiments, and viscometry measurements and cyclic voltammetry studies. The experimental results show that the mode of binding of the complexes to DNA is combination of different mode of interaction.     

Aurophilic interaction in gold(I) thiosaccharinates: Synthesis, characterization, crystal structures and DFT theoretical study

The reaction of gold with thiosaccharin ligand and additional phosphorous coligands is studied. Four new Au(I) complexes with thiosaccharinate as coordinating counteranion: [Au(tsac)(PPh₃)], [Au₂(tsac)₂(dppm)]·EtOH, Au₂(tsac)₂(dppe)·EtOH, and Au(tsac)(Htsac)₂·0.25 EtOH (tsac: thiosaccharinate, C₆H₄C(S)NSO₂⁻, dppm: bis(diphenylphosphino)methane, dppe: bis(diphenylphosphino)ethane) were synthesized and characterized by means of spectroscopic techniques (IR, UV-Vis, and ¹H, ¹³C and ¹³P NMR). The crystal structure of two of them, [Au(tsac)(PPh₃)] and [Au₂(tsac)₂(dppm)]·EtOH, were solved applying single crystal X-ray diffraction and studied using the density functional theory (DFT) formalism. In the latter, the aurophilic interaction between the two gold centers was analyzed and theoretically confirmed.     

Triorganotin(IV) complexes of Schiff base derived from 6-amino-2-mercaptobenzothiazole: Synthesis, characterization and X-ray crystal structures

Nine triorganotin(IV) complexes of the type R₃SnL (L = L1 R = Me 1, Ph 2, PhCH₂3; L = L2 R = Me 4, Ph 5, PhCH₂6; L = L2 R = Me 7, Ph 8, PhCH₂9) have been obtained by reaction of new Schiff base HL1, HL2 or HL3 with triorganotin(IV) chloride in the presence of sodium ethoxide. All the complexes 1-9 were characterized by elemental, IR and NMR spectra analyses. Except for complexes 3, 4, 6, 9, the others were also characterized by X-ray crystallography diffraction analyses, which revealed that complexes 1, 2, 5, 7, 8 were four coordinated and displayed a capped tetrahedron.     

Interaction of metal ions with N-glycosylamines: isolation and characterization of the products of 4,6-O-benzylidene-N-(o-carboxyphenyl)-beta-D-glucopyranosylamine with different metal ions

Metal-ion complexes of Li(+), Na(+), K(+), Mg(2+), Ca(2+), Ba(2+), Pb(2+), Cd(2+), Hg(2+) with 4,6-O-benzylidene-N-(o-carboxyphenyl)-beta-D-glucopyranosylamine were synthesized and isolated as solid products and characterized by analytical means as well as by spectral techniques, such as, 1H and 13C NMR, FTIR, absorption, FAB mass spectrometry, optical rotation and CD. While the alkali metal ions formed ML type of complexes, the other metal ions formed ML(2) type complexes. Molecular weights of the complexes of Li(+), Na(+) and K(+) were established based on the molecular-ion peaks in the FAB mass spectra. The saccharide portion remains in the beta-anomeric form even after the complexation. The spectral data, as well as the trends observed in the chemical shifts, indicate the interaction preferences between this glycosyl amine and different metal ions, and further reveal certain structural features of the complexes.     

Synthesis, characterization and crystal structures of Cd(II) and Zn(II) complexes with 2,2′-biimidazole

The reactions of zinc and cadmium salts with 2,2′-biimidazole (H₂biim) yielded a series of compounds in which the ligand is coordinated in the chelating bidentate mode. ZnCl₂ and [Ag(H₂biim)](NO₃) in methanol in a 2:1 proportion produced Zn(H₂biim)Cl₂, in which the metal has a distorted tetrahedral coordination. A 1:2 ratio led to [Zn(H₂biim)₂(CH₃OH)₂](NO₃)₂, containing an octahedrally coordinated Zn(II) center with the O-bonded methanol ligands occupying trans positions. The corresponding [Cd(H₂biim)₂(CH₃OH)₂](NO₃)₂ compound was obtained from CdCl₂. By starting with Cd(NO₃)₂ and Cd(ClO₄)₂ in aqueous media, the related octahedral bis-chelate compounds [Cd(H₂biim)₂(NO₃)(H₂O)](NO₃) and Cd(H₂biim)₂(ClO₄)₂, respectively, were isolated, the apical positions being filled by perchlorate oxygens in the latter case. With Cd(BF₄)₂, the glass container participated in the reaction and a tris-chelate complex [Cd(H₂biim)₃]₂(SiF₆)(BF₄)₂ · 6EtOH was isolated. The [Cd(H₂biim)₃]²⁺ and ions define an extended hydrogen-bonded network, in which ions surrounded by disordered ethanol molecules occupy large cavities. The two free N-H groups provide H₂biim with a unique ability to form hydrogen bonds and their interactions with counter anions or other acceptors play a determining role in controlling molecular packing. The IR spectra of all compounds are discussed.     

Supramolecular isomers of lanthanides(III): Synthesis, crystal structures and luminescent properties

Six lanthanide coordination polymers La₂(1,4-BDOA)₂(OX)(H₂O) (1), Ln₂(1,4-BDOA)₂(OX)(H₂O) [Ln = La (2); Ln = Pr (3); Ln = Sm (4); Ln = Eu (5); Ln = Tb (6)], [BDOA = benzene-1,4-dioxydiacetate; OX = oxalate] had been prepared under hydrothermal conditions, which were characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis, and single-crystal X-ray diffraction. Compounds 1-6 crystallize in a triclinic system, space group ; compounds 1 and 2 are true structural supramolecular isomers based on BDOA ligands constructed from different acid effects; compounds 2-5 are isostructural and exhibit new 3D 12-connected topological networks, which are the same as the topological structure of 6, while 1 shows another 3D 11-connected topological architecture. Furthermore, the luminescent properties of 5 and 6 were studied.     

Synthesis,X-ray structures and characterization of beryllium phthalocyanine and (2-ethoxyethanol)-aqua-beryllium phthalocyanine

Crystals of beryllium phthalocyanine (I) were obtained from the reaction of beryllium pieces with 1,2-dicyanobenzene at 270 °C. In subsequent preparatory work the beryllium phthalocyanine was transformed into the monoaxially ligated compound (2-ethoxyethanol)-aqua-beryllium phthalocyanine (II). The crystal structures of (I) and (II) were determined by single crystal X-ray diffraction. Based on thermogravimetric measurements, a conversion of the beryllium phthalocyanine into beryllium phthalocyanine monohydrate in wet air has been followed in detail. The beryllium phthalocyanine monohydrate and compound II loose the ligated water and 2-ethoxyethanol in the 150 °C region. The EPR spectra of the beryllium phthalocyanine complexes as exposed to air have been recorded and discussed.     

A series of pyrazolone lanthanide (III) complexes: Synthesis, crystal structures and fluorescence

A series of pyrazolone lanthanide complexes: Ln(PMPP)₃ · 2H₂O · C₂H₅OH (Ln = Nd (1), Sm (2), Gd (3), Dy (4); PMPP = 1-phenyl-3-methyl-4-propionyl-5-pyrazolone) have been synthesized by the hydrothermal method with the starting ligand PMPP-SAH (1-phenyl-3-methyl-4-(salicylidene hydrazone)-propionyl-5-pyrazolone) changed into PMPP during the formation process of complexes. All the complexes were structurally characterized by X-ray crystallography. The fluorescence of these four complexes 1-4 in solid state and DMF solution was investigated via F-4500 spectrophotometer and all of them indicate a fluorescent behavior at room temperature.     

Synthesis, characterization and X-ray crystal structures of copper(II) and nickel(II) complexes with potentially hexadentate Schiff base ligands

Copper(II) and nickel(II) complexes of potentially N₂O₄ Schiff base ligands 2-({[2-(2-{2-[(1-{2-hydroxy-5-[2-phenyl-1-diazenyl]phenyl}methylidene)amino] phenoxy}ethoxy) phenyl]imino}methyl)4-[2-phenyl-1-diazenyl]phenol (H₂L¹) and 2-({[2-(4-{2-[(1-{2-hydroxy-5-[2-phenyl-1-diazenyl]phenyl}methylidene)amino] phenoxy}butoxy) phenyl]imino}methyl)4-[2-phenyl-1-diazenyl]phenol (H₂L²) prepared of 5-phenylazo salicylaldehyde (1) and two various diamines 2-[2-(2-aminophenoxy)ethoxy]aniline (2) and 2-[4-(2-aminophenoxy)butoxy]aniline (3) were synthesized and characterized by a variety of physico-chemical techniques. The single-crystal X-ray diffractions are reported for CuL¹ and NiL². The CuL¹ complex contains copper(II) in a near square-planar environment of N₂O₂ donors. The NiL² complex contains nickel(II) in a distorted octahedral geometry coordination of N₂O₄ donors. In all complexes, H₂L¹ behaves as a tetradentate and H₂L² acts as a hexadentate ligand. Cyclic voltammetry of copper(II) complexes indicate a quasi-reversible redox wave in the negative potential range.     

Platinum(II) and palladium(II) saccharinato complexes with 2,2′:6′,2″-terpyridine: Synthesis, characterization, crystal structures, photoluminescence and thermal studies

[Pd(sac)(terpy)](sac)·4H₂O (1), [Pt(sac)(terpy)](sac)·5H₂O (2), [PdCl(terpy)](sac)·2H₂O (3) and [PtCl(terpy)](sac)·2H₂O (4) (sac = saccharinate, and terpy = 2,2′:6′,2″-terpyridine) have been synthesized and characterized by elemental analysis, FT-IR, ¹H NMR and ¹³C NMR. In 1 and 2, a tridentate terpy ligand together with an N-coordinated sac ligand form the square-planar geometry around the palladium(II) or platinum(II) ions, while one sac anion remains outside the coordination sphere as a counter-ion. X-ray single crystal studies show that the [M(sac)(terpy)]⁺ ions in 1 and 2 reside in the centers of a hydrogen bonded honeycomb network formed by the uncoordinated sac ions and the lattice water molecules. Complexes 3 and 4 are isostructural and consist of a [M(Cl)(terpy)]⁺ cation, a sac anion and two lattice water molecules. The [M(Cl)(terpy)]⁺ ions interact with each other via M-M and π-π stacking interactions and these π interacted units are assembled to a 2D network by water bridges involving the sac ions and lattice water molecules. Convenient synthetic paths for 1-4 are also presented, and spectral, luminescence and thermal properties were discussed.     

Studies of mononuclear and dinuclear complexes of dibromodimethylplatinum(IV): Preparation, characterization and crystal structures

A number of complexes of the types [PtBr₂Me₂(N^?N)] (N^?N = 4,4′-di-Me-2,2′-bpy (1); 4,4′-di-t-Bu-2,2′-bpy (2); 2,2′-bpz (3); bpym (4)) and [PtBr₂Me₂(L)₂] (L = H-pz (5); 4-Me-H-pz (6); H-idz (7); H-im (8); H-bim (9); quaz (10)) are reported. Characterization by NMR (¹H, ¹³C and ¹⁹⁵Pt), IR and EI-MS is given. In addition, crystal structures of several of these complexes are described. Furthermore, interactions within these structures including intramolecular hydrogen bonding and π-π stacking interactions are reported. The reactivity of selected mononuclear complexes was investigated and yielded two dinuclear complexes [PPh₄][(PtBrMe₂)₂(μ-Br)(μ-pz)₂] (11) and [(PtBr₂Me₂)₂(μ-bpym)] (12), respectively. The latter complex is accompanied by a solid-state structure. Finally, the thermal stability of all complexes is reported.     

Two new copper(II) polyamine compounds: Synthesis, characterization and crystal structure

Two new compounds of Cu(II) of stoichiometry CuCl₄(polyamineH₂) containing the polyamines (PA): spermidine or spermine were prepared. Their synthesis, spectroscopic and structural characterization are herein described. The obtained complex with spermidine was characterized by elemental and thermogravimetric analysis, electronic and infrared spectroscopy. In the case of the compound with spermine, crystals were obtained. So, beside all other techniques the compound was also characterized by single crystal X-ray diffractometry. In both cases the species [CuCl₄]²⁻ is present and displays a similar polymeric structure. The X-ray, infrared and electronic spectra are herein discussed based on structural peculiarities of the compounds.     

Synthesis, characterisation and crystal structures of Schiff bases from the reaction of 4,6-O-ethylidene-beta-D-glucopyranosylamine with substituted salicylaldehydes.

Multiple chemical modifications were carried out on D-glucose to result in the corresponding Schiff bases. Such modifications performed on D-glucose not only helped in increasing the solubility of the products in nonaqueous solvents, but also restricted the anomerisation of the saccharide moiety in solution. NMR study of the products revealed the presence of the beta-anomeric form of the saccharide moiety in Me(2)SO solution. All the compounds were characterised by analytical and spectral methods. The literature is devoid of any crystal structures of saccharide-Schiff base combinations of the type reported in this paper. The crystal structures of these molecules exhibited a tridentate, ONO binding core. These studies further revealed that the compounds in the solid state were in the beta-D-pyranose form with the (4)C(1) chair conformation. The compounds exhibited interesting lattice structures assisted through weak interactions of the type O-H...O and C-H...O. The lattice structure of one of these compounds exhibited channels filled with chloroform molecules.     

Novel 2-aminopyridine liganded Pd(II) N-heterocyclic carbene complexes: Synthesis,characterization, crystal structure and bioactivity properties

In this work, the synthesis, crystal structure, characterization, and enzyme inhibition effects of the novel a series of 2-aminopyridine liganded Pd(II) N-heterocyclic carbene (NHC) complexes were examined. These complexes of the Pd-based were synthesized from PEPPSI complexes and 2-aminopyridine. The novel complexes were characterized by using ¹³C NMR, ¹H NMR, elemental analysis, and FTIR spectroscopy techniques. Also, crystal structures of the two compounds were recorded by using single-crystal X-ray diffraction assay. Also, these complexes were tested toward some metabolic enzymes like α-glycosidase, aldose reductase, butyrylcholinesterase, acetylcholinesterase enzymes, and carbonic anhydrase I, and II isoforms. The novel 2-aminopyridine liganded (NHC)PdI₂(2-aminopyridine) complexes (1a-i) showed Ki values of in range of 5.78 ± 0.33–22.51 ± 8.59 nM against hCA I, 13.77 ± 2.21–30.81 ± 4.87 nM against hCA II, 0.44 ± 0.08–1.87 ± 0.11 nM against AChE and 3.25 ± 0.34–12.89 ± 4.77 nM against BChE. Additionally, we studied the inhibition effect of these derivatives on aldose reductase and α-glycosidase enzymes. For these compounds, compound 1d showed maximum inhibition effect against AR with a Ki value of 360.37 ± 55.82 nM. Finally, all compounds were tested for the inhibition of α-glycosidase enzyme, which recorded efficient inhibition profiles with Ki values in the range of 4.44 ± 0.65–12.67 ± 2.50 nM against α-glycosidase.     

Synthesis, X-ray crystal structures and linear and nonlinear optical characterization of a series of nickel(II) and copper(II) salicylaldiminato complexes

A series of nickel(II) and copper(II) salicylaldiminato complexes containing side arms with either potentially coordinating (OH) or non-coordinating (Cl) functional groups have been prepared and characterized by X-ray crystallography. The Cu(II) complexes are square planar, but the Ni(II) complexes prefer octahedral coordination. Linear absorption spectra depend on the metal and on its coordination geometry, with the octahedral Ni(II) complexes being the most weakly absorbing at 532 nm and the square planar Cu(II) complexes being the most strongly absorbing at 532 nm. The third-order nonlinear optical properties of the complexes have been characterized using degenerate four-wave mixing (DFWM) and Z-scan. Two different Z-scan experimental configurations were used, one of which employs a Gaussian beam in a tightly focused geometry while the other employs a top-hat beam and a more relaxed focus. The observed third-order optical nonlinearity is primarily due to transient thermal (photo-acoustic) effects associated with linear absorption in the samples. The dependence of the third-order nonlinear optical properties on the linear absorption means that the nonlinear optical properties vary substantially between the complexes even though they all contain the same chromophore. The hyperpolarizability of one of the complexes, γ = 1.3 × 10⁻³⁰ esu, rivals the nonlinearities measured at 532 nm in expanded porphyrin and phthalocyanine complexes.