Search

Crystals of the title compound, (C5H8N3)3[VO2(C2O4)2]·2.5H2O, a mononuclear VV complex, were obtained by slow evaporation at room temperature of an aqueous solution containing vanadium pentoxide, oxalic acid and 2,6-di­amino­pyridine. The asymmetric unit contains one bis­(oxalato)dioxovanadate(V) anionic complex, three 2,6-di­amino­pyridinium cations and two and a half uncoordinated water mol­ecules. The mononuclear vanadium(V) anions are connected to the organic cations and water mol­ecules through a strong N--H...O and O--H...O hydrogen-bond network, consolidated by π-π stacking inter­actions, to form a three-dimensional structure. [ABSTRACT FROM AUTHOR]

The title copper(II) complex, [Cu(C18H19N3O3)(C3H4N2)], consists of a tridentate ligand synthesized from l-leucine and azobenzene-salicylaldehyde. One imidazole molecule is additionally coordinated to the copper(II) ion in the equatorial plane. The crystal structure features N--H...O hydrogen bonds. A Hirshfeld surface analysis indicates that the most important contributions to the packing are from H...H (52.0%) and C...H/H...C (17.9%) contacts. [ABSTRACT FROM AUTHOR]

The title azo compound, C16H16N4, was synthesized from 2,6-dimethylaniline. The diazenyl group adopts a trans (E) conformation, with an N N bond length of 1.265 (4) Å. The pyrazole ring is approximately planar. In the crystal, zigzag chains along the b-axis direction with a C(3) is graph-set motif are formed by N--H• • •N hydrogen bonds involving the pyrazole moiety. [ABSTRACT FROM AUTHOR]

The title copper(II) complex, [Cu(C16H13NO4)(C3H4N2)], consists of a tridentate ligand synthesized from l-tyrosine and salicylaldehyde. One imidazole molecule is additionally coordinating to the copper(II) ion. The crystal structure features N--H--O, O--H--O and C--H--O hydrogen bonds. The Hirshfeld surface analysis indicates that the most important contributions to the packing are from H--H (37.9%), C--H (28.2%) and O--H/H--O (21.2%) contacts. [ABSTRACT FROM AUTHOR]

The title copper(II) complex, [Cu(C16H13NO4)(C3H4N2)], consists of a tridentate ligand synthesized from L-tyrosine and salicylaldehyde. One imidazole molecule is additionally coordinating to the copper(II) ion. The crystal structure features N--H⋯O, O--H⋯O and C--H⋯O hydrogen bonds. The Hirshfeld surface analysis indicates that the most important contributions to the packing are from H⋯H (37.9%), C⋯H (28.2%) and O⋯H/H⋯O (21.2%) contacts. [ABSTRACT FROM AUTHOR]

The molecular structure of the title compound, [Cu(C12H13N2O3)(H2O)2]·-[Cu(C12H13N2O3)(H2O)], consists of two different molecules in the asymmetric unit. Both of the structures consist of a tridentate ligand synthesized from l-valine and salicylaldehyde, and one water molecule or two water molecules coordinating to CuII. They have a square-planar (molecule 1) or a squarepyramidal (molecule 2) coordination geometry. In the crystal, the molecules form intra- and intermolecular O--H· · ·O hydrogen bonds involving the coordinated water molecules and other sites. A Hirshfeld surface analysis indicated that the most important contributions to the packing are from H· · ·H [52.9% (molecule 1) and 51.1% (molecule 2)] and H· · ·O/O· · ·H [21.2% (molecule 1) and 25.8% (molecule 2)] contacts. In addition, an electrostatic potential map was also obtained from DFT calculations to support the discussion of the intermolecular interactions. [ABSTRACT FROM AUTHOR]

The structure of the complex salt, cis-[Cr(NCS)2(cyclam)]2[Cr2O7]·H2O (cyclam = 1,4,8,11-tetraazacyclotetradecane, C10H24N4), has been determined from synchrotron data. The asymmetric unit comprises of one [Cr(NCS)2(cyclam)]+ cation, one half of a Cr2O72- anion (completed by inversion symmetry) and one half of a water molecule (completed by twofold rotation symmetry). The CrIII ion is coordinated by the four cyclam N atoms and by two N atoms of cis-arranged thiocyanate anions, displaying a distorted octahedral coordination sphere. The Cr-N(cyclam) bond lengths are in the range 2.080 (2) to 2.097 (2) Å while the average Cr-N(NCS) bond length is 1.985 (4) Å . The macrocyclic cyclam moiety adopts the cis-V conformation. The bridging O atom of the dichromate anion is disordered around an inversion centre, leading to a bending of the Cr-O-Cr bridging angle [157.7 (3)°]; the anion has a staggered conformation. The crystal structure is stabilized by intermolecular hydrogen bonds involving the cyclam N-H groups and water O-H groups as donor groups, and the O atoms of the Cr2O72- anion and water molecules as acceptor groups, giving rise to a three-dimensional network. [ABSTRACT FROM AUTHOR]

We have prepared four new Cu(II) complexes containing valine moieties with imidazole ligands at the fourth coordination sites and examined their photo-induced reactions with TiO2 in order of understanding the reaction mechanisms. Under a nitrogen atmosphere, the intermolecular electron transfer reactions (essentially supramolecular interactions) of these systems, which resulted in the reduction of Cu(II) species to Cu(I) ones, occurred after UV light irradiation. In this study, we have investigated the conditions of the redox reactions in view of substituent effects of aldehyde moieties. The results of cyclic voltammetry (CV) on an rotating ring-disk electrode (RRDE) suggested that the substitution effects and redox potentials were correlated. Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations were also performed to simulate the UV-Vis and circular dichroism (CD) spectra; the results revealed a reasonably good correlation between the substituent effects and the highest occupied molecular orbitals and the lowest unoccupied molecular orbitals (HOMO-LUMO) gaps associated with the most intense transition bands. In addition, we summarized the substitution effects of Cu(II) complexes for their corresponding UV light-induced reactions. [ABSTRACT FROM AUTHOR]

Four chiral Schiff base binuclear 3d-4f complexes (NdNi, NdCu, GdNi, and GdCu) have been prepared and characterized by means of electronic and CD spectra, IR spectra, magnetic measurements, and X-ray crystallography (NdNi). A so-called artifact peak of solid state CD spectra, which was characteristic of oriented molecules without free molecular rotation, appeared at about 470 nm. Magnetic data of the complexes in the solid state (powder) and in PMMA cast films or solutions indicated that only GdCu preserved molecular structures in various matrixes of soft maters. For the first time, we have used the changes of intensity of artifact CD peaks to detect properties of environmental (media solid state (KBr pellets), PMMA cast films, concentration dependence of PMMA in acetone solutions, and pure acetone solution) for chiral 3d-4f complexes (GdCu). Rigid matrix keeping anisotropic orientation exhibited a decrease in the intensity of the artifact CD peak toward negative values. The present results suggest that solid state artifact CD peaks can be affected by environmental viscosity of a soft mater matrix. [ABSTRACT FROM AUTHOR]

In the title complex, [Sm(NO3)3(C30H28N2O4)], the Sm atom is surrounded by ten O atoms. The (S,S)-2,2′-{[(1,2-di­phenyl­ethane-1,2-di­yl)bis­[(aza­niumylyl­idene)methanylyl­idene]}bis­(6-meth­oxy­phenolate) ligand, obtained from o-vanillin and (1S,2S)-(−)-1,2-di­phenyl­ethyl­enedi­amine, exhibits a slightly distorted planar arrangement of the four coordinated O atoms. In the crystal, the complex shows intra­molecular N—H...O hydrogen bonds and weak inter­molecular C—H...O hydrogen bonds. The Hirshfeld surface analysis indicates that the most important contributions to the packing are from H...H (33.5%), O...H (34.1%) and C...H (21.7%) contacts. [ABSTRACT FROM AUTHOR]

The compound, {6,6′-dimeth­oxy-2,2′-[(4-azaheptane-1,7-di­yl)bis­(nitrilo­meth­an­yl­idyne)]diphenolato}zinc(II) methanol monosolvate, [Zn(C22H27N3O4)]·CH3OH, at 298 K crystallizes in the ortho­rhom­bic space group Pna21. The Zn atom is coordinated by a penta­dentate Schiff base ligand in a distorted trigonal–bipyramidal N3O2 geometry. The equatorial plane is formed by the two phenolic O and one amine N atom. The axial positions are occupied by two amine N atoms. The distorted bipyramidal geometry is also supported by the trigonality index (τ), which is found to be 0.85 for the mol­ecule. In the crystal, methanol solvent mol­ecule is connected to the complex mol­ecule by an O—H...O hydrogen bond and the complex mol­ecules are connected by weak supra­molecular inter­actions, so achiral mol­ecules generate a chiral crystal. The Hirshfeld surface analysis suggests that H...H contacts account for the largest percentage of all inter­actions. [ABSTRACT FROM AUTHOR]

In the title complex mol­ecule, [Cu(C11H11NO4)(CH4O)(H2O)], the Cu atom is coordinated in a distorted square-pyramidal geometry by a tridentate ligand synthesized from L-threonine and salicyl­aldehyde, one methanol mol­ecule and one water mol­ecule. In the crystal, the mol­ecules show intra- and inter­molecular O—H...O hydrogen bonds. The Hirshfeld surface analysis indicates that the most important contributions to the packing are H...H (49.4%) and H...O/O...H (31.3%) contacts. [ABSTRACT FROM AUTHOR]

Co-crystallization of racemic 1-cyclohexyl-1-phenyl-3-(piperidin-1-yl)propan-1-ol (trihexyphenidyl) with 3,5-dinitrobenzoic acid gives a simple 1:1 salt, namely 1-(3-cyclohexyl-3-hydroxy-3-phenylpropyl)piperidin-1-ium 3,5-dinitrobenzoate, C20H32NO+·C7H3N2O6 -, (I), whereas a similar co-crystallization using (Z)-3-(2-chloro-9H-thioxanthen-9-yl)-N,N-dimethylpropan-1-amine (chlorprothixene) gives a 1:2 acid salt, namely (Z)-3-(2-chloro-9H-thioxanthen-9-yl)-N,N-dimethylpropan-1-aminium hydrogen bis(3,5-dinitrobenzoate), C18H19ClNS+·-[H(C7H3N2O6)2]-, (II), the anion of which contains a very short O--H...O hydrogen bond, with dimensions O--H = 1.04 (3) Å, H...O = 1.41 (3) Å, O...O = 2.4197 (15) Åand O--H...O = 161 (3)°. In the cation of (I), the cyclohexyl and piperidyl rings both adopt chair conformations, whereas in the cation of (II), the central heterocyclic ring adopts a boat conformation, so that the dihedral angle between the two aryl rings is 41.56 (4)°. A combination of O--H...O, N--H...O and C--H...O hydrogen bonds links the ions of (I) into a complex chain of rings, and these chains are linked into sheets by π-π stacking interactions between inversion-related pairs of anions. In compound (II), a different combination of O--H...O, N--H...O and C--H...O hydrogen bonds links the ions into sheets. Comparisons are made with some related structures. [ABSTRACT FROM AUTHOR]

In each of the compounds 1-[(1,3-benzodioxol-5-yl)methyl]-4-(3-fluorobenzoyl)-piperazine, C19H19FN2O3 (I), 1-[(1,3-benzodioxol-5-yl)methyl]-4-(2,6-difluorobenzoyl) piperazine, C19H18F2N2O3 (II), and 1-[(1,3-benzodioxol-5-yl)methyl]-4-(2,4-dichlorobenzoyl)piperazine, C19H19Cl2N2O3 (III), the piperazine rings adopt a chair conformation with the (1,3-benzodioxol-5-yl)methyl substituent occupying an equatorial site: the five-membered rings are all slightly folded across the O...O line leading to envelope conformations. The dihedral angle between the planar amidic fragment and the haloaryl ring is 62.97 (5)° in (I) but 77.72 (12)° and 75.50 (5)° in (II) and (III), respectively. Despite their similarity in constitution and conformation, the supramolecular interactions in (I)-(III) differ: in (I), a combination of C--H...O and C--H...π(arene) hydrogen bonds links the molecules into a three-dimensional framework structure, but there are no hydrogen bonds of any sort in either (II) or (III), although the structure of (III) contains a short Cl...Cl contact between inversion-related pairs of molecules. [ABSTRACT FROM AUTHOR]

In 1-(2-iodobenzoyl)-4-(pyrimidin-2-yl)piperazine, C15H15IN4O, the central piperazine ring adopts an almost perfect chair conformation with the pyrimidine substituent in an equatorial site. The planar amide unit makes a dihedral angle of 80.44 (7)° with the phenyl ring. A combination of C--H...O and C--H...π(arene) hydrogen bonds links the molecules into a complex threedimensional network structure, augmented by a π-π stacking interaction and an I...N halogen bond, all involving different pairs of inversion-related molecules. Comparisons are made with the structures of a number of related compounds. [ABSTRACT FROM AUTHOR]

The title compound, C10H10O4, was synthesized from tetramethyl-1,4-benzoquinone. In the crystal, the almost planar molecule (r.m.s. deviation = 0.024 Å ) forms intramolecular hydrogen bonds between the aldehyde and hydroxy groups and exhibits C2v symmetry. This achiral molecule crystallizes in the chiral space group P21 with intermolecular O--H• • •O and C--H• • •O hydrogen bonding and C--H• • •π and C=O• • •π interactions stabilizing the crystal packing. [ABSTRACT FROM AUTHOR]

Naphtheledicarboxylato ((NDC2-) bridged coordination polymers (CPs) along with (E)-1-methyl-2-(p-chlorophenylazo)imidazole (ClPai-Me) coordination to Co(II), [Co(∝-NDC)0.5(∝4-NDC)0.5(ClPai-Me)]·0.5H2O (1), and to Zn(II), [Zn(∝-NDC)0.5(∝4-NDC)0.5(ClPai-Me)]·0.5H2O (2), have been characterized. In the single crystal X-ray structure of 1, ClPai-Me chelates to the Co(II) ion by N(azo) and N(imidazolyl), whereas in compound 2, it acts as a monodentate N(imidazolyl) donor to the Zn(II) ion. The coordination atmosphere around Co(II) in the 1 ion is distorted octahedral CoN2O4, whereas in the case of 2, it is distorted square pyramidal ZnNO4. Compounds 1 and 2 exhibit the right-handed (P) and left-handed (M) one-dimensional helical chain. NDC-2 is serving as a bridge between two M(II) ions to constitute µ-NDC and four M(II) ions to construct µ4-NDC to assemble three-dimensional polymers. Upon UV light (369 nm) irradiation, compound 2 shows trans-to-cis isomerization of -N═N-C6H4-Cl-p both in the solid and solution state but 1 remains silent. Prolonged light irradiation in the solid state (film phase) does not change the coordinated ClPai-Me in complexes 1 and 2, whereas the free stage of ClPai-Me undergoes photoreduction of the -N═N- bond and forms azo radicals with a concomitant permanent color change. The persistence of the radical has been characterized by electron paramagnetic resonance spectroscopy in the solid state at g = 2.009. The effective magnetic moment of 1 is 4.17 µB at 300 K, Co(II) ion of S = 3/2. [ABSTRACT FROM AUTHOR]

Reactions of nickel(II) and cobalt(II) salts with various N1-substituted thiosemicarbazones [R1R2C2=N3–N2H–C1(=S)–N1HR3, H2L; R1 = C6H5-, R2 = H, H2L1(R3 = Me); H2L2(R3 = Ph), R1 = 2-OHC6H4-, R2 = H, H2L3(R3 = Me), H2L4(R3 = Et), H2L5(R3 = Ph); R2 = Me, H2L6(R3 = Me), R2 = Me, H2L7(R3 = Et) and R2, R3 = H, Me, H2L8(R1 = C4H3S), H2L9(R1 = C4H3O)] are described. Reactions of Ni(OAc)2 with the ligands having R1 as phenyl group at C2 carbon (H2L1, H2L2) gave complexes, [Ni(κ2-N3, S-HL)2] (HL− = HL1, 1; HL2, 2). Other ligands with R1 as 2-hydroxyphenyl groups, namely, H2L3–H2L7, with Ni(OAc)2 yielded rust colored compounds, {Ni(κ3-O, N3, S–L)} (L2− = L3–L7) which after the addition of PPh2-CH2-PPh2 yielded dinuclear, [Ni2(κ3-O, N3, S–L)2(μ-P, P–PPh2–CH2–PPh2)] (L2− = L3, 3; L4, 4; L5, 5) and mononuclear, [Ni(κ3-O, N3, S–L)(κ1-P–PPh2–CH2–PPh2)] (L2− = L6, 6; L7, 7) complexes. Likewise, {Ni(κ3-O, N3, S-L5} with 2-phenylpyridine(2-Phpy) has yielded a mononuclear complex, [Ni(κ3-O, N3, S–L5)(κ1-N-2-Phpy)] 8. The geometry around Ni metal center can be formally described as square planar in each of complexes 1–8. Reactions of CoCl2 with H2L8 and H2L9 involved oxidation of CoII to CoIII and yielded octahedral complexes, [Co(κ2-N, S–HL)3] (HL− = HL8, 9; HL9, 10). [ABSTRACT FROM AUTHOR]

A series of palladium(II) complexes involving C–H and N–H bond activations of the R1 rings of thiosemicarbazones {R1(R2)C2–N3–N2(H)–C1(ᆖS)–N1HR3; R1, R2: thiopheneyl, Me, H2L1 (R3 = Me), H2L2 (R3 = Ph); R1, R2: Ph, Me, H2L3 (R3 = Me), H2L4 (R3 = Ph); R1, R2: Ph, Ph, H2L5 (R3 = Me), H2L6 (R3 = Ph) and R1, R2: pyrrole, Me, H2L7 (R3 = Me), H2L8 (R3 = Ph)} are described. Methyl group (R2) at C2 carbon in H2L1 and H2L2 induced C–H bond activation of the thiopheneyl ring and formed cyclometallated complexes, [Pd(κ3–C4,N3,S–L)(PPh3)] (L = L1, 1; L2, 2). Similarly, phenyl rings (R1) in H2L3, H2L4, H2L5, H2L6 at C2 carbon have shown C–H activations forming cyclometallated complexes, [Pd(κ3–C4,N3,S–L)(PPh3)] (L = L3, 3; L4, 4; L5, 5; L6, 6). However, pyrrole ring did not exhibit similar C–H activation behavior, rather involved N–H activation and formed complexes, [Pd(κ3–N4,N3,S–L)(PPh3)] {L = L7, 7; L8, 8}. All these complexes have been characterized with the help of analytical data, spectroscopic techniques (IR, 1H and 31P NMR), and single crystal X-ray crystallography (1, 2, 4, 5, 7 and 8). The thiosemicarbazone ligands behave as dinegative C4, N3, S-chelating in 1–6 and N4, N3, S-chelating in complexes 7 and 8. Interestingly, complexes 2, 4 and 8, with phenyl substituent at N1 atom, have two independent molecules in their respective crystal lattices. [ABSTRACT FROM AUTHOR]

The influence of substituents at the C2carbon of N1-substituted thiosemicarbazones, {C4H3X–C2(CH3)N3–N2H–C1(S)N1HR2} (X = O, S) on the geometry of nickel(ii) complexes has been investigated. The presence of a methyl group at the C2position of 2-acetylfuran-N1-substituted thiosemicarbazones {(C4H3O)–C2(CH3)N3–N2H–C1(S)N1HR2, R2= CH3, HaftscN–Me; C2H5, HaftscN–Et; C6H5, HaftscN–Ph} induces unusual coordination by the furan ring and yielded high spin octahedral nickel(ii) complexes, [Ni(κ3-O, N3, S-aftscN–R2)2], CH31, C2H52, and 2[Ni((κ3-O, N3, S-aftscN–Ph)2] 3(μeff= 2.98, 1; 2.96, 2; 2.92, 3). With 2-acetylthiophene-N1-substituted thiosemicarbazones, {(C4H3S)-C2(CH3)N3-N2H–C1(S)N1HR2, R2= CH3, HattscN–Me; C2H5, HattscN–Et; C6H5, HattscN–Ph}, N3, S chelated low spin transsquare planar complexes, {[Ni(κ3-O, N3, S-attscN–R2)2], R2= CH3, 4; C2H5, 5; C6H5, 6} with pendant thiophene rings have been obtained. The bigger sized sulfur atoms of the thiophene rings form short intramolecular contacts with the deprotonated hydrazinic nitrogen atoms (SN2) inhibiting its lability for possible coordination to nickel(ii). Complexes have one independent molecule (1) or two independent molecules (2, 3) in their respective crystal lattices. The simultaneous presence of methyl groups at the C2and N1atoms of 2-acetylthiophene-N1-methylthiosemicarbazone (HattscN–Me) have facilitated the binding of triphenylphosphine in three-coordinate copper(i) halide complexes, [CuX(η1-S-HattscN–Me)(Ph3P)] (X, Br, 7; Cl, 8), which represent an unusual donor set of ligands, namely, triphenylphosphine, sulfur of a thio-ligand and a halide. [ABSTRACT FROM AUTHOR]

Two structural series, including seven isomorphous heterodinuclear complexes, [Ln(DMSO)4(H2O)3(μ-CN)M(CN)5]·H2O ([La-Fe] (1), [Pr-Fe] (2), [Pr-Co] (3), [Nd-Fe] (4), [Nd-Co] (5), [Sm-Fe] (6) and [Sm-Co] (7)), and seven isostructural 2-D stairlike cyano-bridged bimetallic assemblies, [Ln(DMSO)2(H2O)(μ-CN)4M(CN)2]n ([La-Fe]n (8), [Pr-Fe]n (9), [Pr-Co]n (10), [Nd-Fe]n (11), [Nd-Co]n (12), [Sm-Fe]n (13) and [Sm-Co]n (14)) (DMSO = dimethylsulfoxide), have been rationally prepared by a facile approach, a ball-milling method, and characterized by X-ray diffraction and magnetic measurements. The isomorphous structures, in conjunction with the diamagnetism of the Co3+ and La3+ ions, allow an approximation to the nature of coupling between the iron(lll) and lanthanide(lll) ions in the Ln3+-Fe3+ complexes. The Ln3+-Fe3+ interaction is ferromagnetic for the dinuclear [Pr-Fe] (2), [Nd-Fe] (4), and [Sm-Fe] (6) systems and for the 2-D [Pr-Fe]n (9), [Nd-Fe]n (11), and [Sm-Fe]n (13) assemblies. [ABSTRACT FROM AUTHOR]

Four cyano-bridged 4f−3d (lanthanide−transition metal) bimetallic assemblies, Sm(DMF)2(H2O)3(-CN)3M(CN)3n·nH2O (M Fe (1), Co (2)) with 2-D monolayered structures and Sm(DMF)(H2O)3(-CN)4M(CN)2n·nH2O (M Fe (3), Co (4)) with 2-D bilayered structures (DMF N,N-dimethylformamide), were rationally prepared by a facile approach, a ball-milling method, and characterized by X-ray diffraction studies and magnetic measurements. The unprecedented 2-D bilayered 4f−3d hexacyanometalates (3and 4) were obtained by controllably reducing the half amount of DMF in the reactive system in comparison with 1and 2through a ball-milling method. [ABSTRACT FROM AUTHOR]