Search

A series of substituted pyridine dialcohols (2,6-bis(hydroxyalkyl)pyridines), 1-4, was used for the synthesis of various types of aluminum complexes. Aluminum methyl derivatives, 2-4a, were obtained by the reaction of AlMe3 with the corresponding ligand or transmetallation reactions of germylenes. Aluminum chloride complexes, 3-4b, were obtained by substitution of the Me group under the action of chlorinating agents. Methoxy-, 2-4c, or benzyloxy-, 2d, aluminum complexes were synthesized in transalkoxylation reaction of Me2Al(OX) (X = Me, Bn) by the corresponding ligand. All complexes obtained were thoroughly investigated by multinuclear NMR and X-ray analysis. It has been established that the structure of the ligand (number of carbon atoms) determines the nature of the complexes formed. Compounds were used as initiators of ring-opening polymerization of l-lactide and ε-caprolactone and showed moderate activity with controlled or immortal character.

In the title compound, [Ti2(C16H14N2O2)2O2]·2CHCl3, the Ti(IV) atom in the centrosymmetric complex has a distorted octa-hedral N2O4 coordination environment and is linked via two μ2-oxido bridges into a dinuclear centrosymmetric com-plex, with a Ti⋯Ti separation of 2.7794 (8) Å. In the salen (N,N'-ethyl-enebis(salicyl-imine)) ligand, the two salicyl-imine units make a dihedral angle of 45.31 (5)°. The complex mol-ecules are stacked parallel to [100], forming channels in which the solvent chloro-form mol-ecules are located. C-H⋯O hydrogen-bonding inter-actions between the complex mol-ecules and the solvent mol-ecules consolidate the crystal packing.

This article represents a systematical investigation on the structures of silver(I) dicarboxylate incorporating secondary ligands, revealing that the secondary interactions could play an important role in interlinking low-dimensional entities to high-dimensional supramolecular frameworks. A new 2D silver(I) crystalline dicarboxylate, {[Ag(6)(ADC)(3)(H(2)O)(1.5)](2).5.18H(2)O}(n) (1) (H(2)ADC = 1,3-adamantanedicarboxylic acid), has been obtained by slow diffusion of corresponding precursors. To investigate the influence of the properties of pyridylic neutral ligands on the complex structures based on compound 1, five kinds of neutral ligands (bipy = 4,4'-bipyridine; bpa = 1,2-bis(4-pyridyl)ethane; bpe = 1,2-bis(4-pyridyl)ethene; bpp = 1,3-bis(4-pyridyl)propane; bpdap = N,N'-bis(3-pyridyl)-2,6-diaminopyridine) were selected, and a series of new silver(I) dicarboxylate have been synthesized: {[Ag(bpa)(HADC)]}(n) (2), {[Ag(bpp)(HADC)].CH(3)OH}(n) (3), {[Ag(4)(bpe)(3)(ADC)(2)].2H(2)O}(n) (4), {[Ag(bipy)(HADC)].H(2)O}(n) (5), {[Ag(2)(bipy)(2)(ADC)].6H(2)O}(n) (6), and [Ag(8)(bpdap)(4)(ADC)(4)].2C(2)H(5)OH.6H(2)O (7). Single-crystal X-ray structural analysis shows that complexes 1 and 4 are formed by hexanuclear and tetranuclear Ag(I) clusters with weak Ag-Ag interactions. Complexes 2 and 3 are dinuclear structures, 5 and 6 exhibit an infinite 1D chain structure, whereas 7 is a discrete octanuclear Ag(I) unit. The structures of 1-7 span from dinuclear, tetranuclear, hexanuclear, to octanuclear Ag(I) complexes, which indicates that secondary ligands do play important roles in the formation of such coordination architectures. Thermal stability, X-ray powder diffraction and luminescent properties of the compounds are also discussed.

Four distinct hydrogen-bonding topologies were observed in the structures of six diethanolamine ligands. These compounds are (1R*,2R*)-2-[(2-hydroxyethyl)(methyl)amino]-1,2-diphenylethanol, C(17)H(21)NO(2), (I), 1-[(2S)-2-(hydroxydiphenylmethyl)pyrrolidin-1-yl]-2-methylpropan-2-ol, C(21)H(27)NO(2), (II), 2-[(2-hydroxyethyl)(methyl)amino]-1,1-diphenylethanol, C(17)H(21)NO(2), (III), 1-{(2-hydroxy-2-methylpropyl)[(1S)-1-phenylethyl]amino}-2-methylpropan-2-ol, C(16)H(27)NO(2), (IV), 1-{[(2R)-2-hydroxy-2-phenylethyl][(1S)-1-phenylethyl]amino}-2-methylpropan-2-ol, C(20)H(27)NO(2), (V), and (1R*,2S*)-2-[(2-hydroxyethyl)(methyl)amino]-1,2-diphenylethanol, C(17)H(21)NO(2), (VI). In each compound, all ;active' hydroxy H atoms are engaged in hydrogen bonding, but the N atoms are not involved in intermolecular hydrogen bonding. In the structures of (I), (II) and (IV)-(VI), molecules are linked into chains by intermolecular O-H...O interactions. These chains are organized in such a way as to hide the hydrophilic groups inside, and so the outer surfaces of the chains are hydrophobic. The structure of (VI) contains two distinct non-equivalent systems of intermolecular O-H...O hydrogen bonds formed by disordered hydroxy H atoms.

A series of new metal-organic coordination complexes, {[Ni(IP)(H(2)O)(4)].(2H(2)O)(SO(4))} (1), [M(IP)(mu(2)-SO(4))(H(2)O)(2)] (M = Zn 2 , and M = Mn 3 ), {[M(2)(IP)(2)(mu(2)-SO(4))(2)(H(2)O)(4)].2H(2)O} (M = Zn 4 , and M = Co 5 ), {[Mn(2)(IP)(mu(2)-SO(4))(H(2)O)(2)].(6.5H(2)O)(sdba)} (6), {[Mn(IP)(2)(H(2)O)(2)][Mn(pydc)(2)(H(2)O)(2)].(4H(2)O)} (7), {[Mn(IP)(fum)(H(2)O)].H(2)O} (8), {[M(3)(IP)(3)(fum)(3)].(8H(2)O)} (M = Cd 9, and M = Zn 10 ), {[Cd(2)(IP)(2)(bptc)(H(2)O)(2)].(7.3H(2)O)} (11), {[Zn(2)(IP)(2)(bptc)(H(2)O)(2)].(3H(2)O)} (12), {Cd(1,4-BDC)(IP)(H(2)O)].(0.5H(2)O)} (13), {[Mn(1,4-BDC)(IP)(H(2)O)].H(2)O} (14), {[Zn(2)(1,4-BDC)(2)(IP)].2.5H(2)O} (15) (IP = 1H-imidazo[4,5-f][1,10]-phenanthroline, H(2)sdba = 4,4'-sulfonyldibenzoic acid, H(2)pydc = pyridine-2,6-dicarboxylic acid, H(2)fum = fumaric acid, H(4)bptc = 3,3',4,4'-benzophenonetetracarboxylic acid and 1,4-H(2)BDC = 1,4-benzendicarboxylic acid) were prepared via self-assembly of pharmaceutical agent IP with different metal sulfates in the absence/presence of the carboxylate under mild conditions. All these compounds were structurally determined by single-crystal X-ray diffraction. Compounds 2-6 crystallize with N-donor chelating ligands and sulfate anion linkers. Complexes 2-6 possess sulfate anions with mu(2)-bridging modes, the roles of sulfate anions result in 1D chains (2 and 3) and dinuclear units (4, 5and 6). For complex 7 , two different Mn units are chelated by two IP and pydc ligands, respectively. Compound 8 is a 1D chain connected by fum ligands. Polymers 9-12 exhibit 2D network structures composed of tetrametallic and hexametallic clusters. The Cd(ii)/Zn(ii) layers are interdigitated in pairs for complexes 11 and 12 by stacking forces, which exhibit unusual 2D-->3D interdigitated architectures. In 13 and 14, they show 1D undulating and linear chains due to the different coordinate modes of 1,4-BDC. IP firstly acts in a tridentate mode via the two N atoms of pyridyl rings and the third N atom of imidazole ring, and the two carboxylate groups of 1,4-BDC ligand taking three types of coordinative modes connect Zn atoms into a complicated 3D network in 15 . The structural differences among complexes 1-15 indicate the backbone of such dicarboxylate ligands, nature of metal resources and the ratio of metal to ligand play important roles in modulating the formation of the coordination polymers. Thermal stabilities of these crystalline materials, fluorescent properties of these complexes and TD-DFT calculation of spectra of IP were also investigated.

Syntheses of a series of novel germanium complexes, viz. RN(CH(2)CH(2)NC(6)F(5))(2)GeHal(2) (, R = Me, Hal = Cl; , R = Me, Hal = Br; , R = PhCH(2), Hal = Cl; , R = PhCH(2), Hal = Br), as well as MeN[CH(2)(2-C(4)H(3)N)](2)GeHal(2) (, Hal = Cl; , Hal = Br), by the reaction of GeHal(4) with dilithium salts of corresponding triamines are presented. PhCH(2)N(CH(2)CH(2)NSiMe(3))(2)GeCl(2) () was prepared analogously from triamine . Other approaches to the synthesized compounds were also tested. Unexpected complexes [N[upper bond 1 start](CH(2)CH(2)NSiMe(3))(2)Ge[upper bond 1 end](Hal)](2) (, Hal = Cl; , Hal = Br) were obtained by the reaction of GeHal(4) with dilithium salt of Me(3)SiN(CH(2)CH(2)NHSiMe(3))(2) (). DFT calculations on this reaction were carried out and discussed. Composition and structures of the novel compounds were established by elemental analyses, (1)H, (13)C, and (19)F NMR spectroscopy. The X-ray structural studies of and clearly indicated the presence of a transannular interaction N(ax)-->Ge for all studied compounds.

The title compound, C24H17F10N3O2, exhibits intramolecular N-H...O hydrogen bonding, as well as intramolecular Ar...Ar(F) face-to-face interactions. The molecules are linked together by N-H...F-C hydrogen bonds, forming chains parallel to the a axis. Adjacent symmetry-related chains are combined in double zipper-like ribbons by parallel Ar(F)...Ar(F) offset pi-stacking interactions.

Synthesis of the title compounds, viz. [RN(CH2CHR'O)2]2Ge (1, R = Me, R' = H; 2, R = Me, R' = Ph; 3, R = Ph, R' = H), by the reaction of 2 equiv of corresponding dialkanolamines RN(CH2CHR'OH)2 (4, R = Me, R' = H; 5, R = Me, R' = Ph; 6, R = Ph, R' = H) with (AlkO)4Ge is reported. Composition and structures of all novel compounds were established by 1H and 13C NMR spectroscopy and mass spectrometry as well as elemental analysis data. The single-crystal X-ray diffraction of 2 has clearly indicated the presence of two transannular interactions Ge<--N in the compound. N atoms are cis-orientated. The compound 3 possesses long Ge...N distances. The structural data obtained from geometry optimizations by DFT calculations on 1-3 reproduces experimental results. Both cis- and trans-isomers were studied, and cis-configuration was found to be more thermodynamically stable for all three compounds. The transition states for possible cis <--> trans rearrangement processes in 1-3 were calculated. The properties of the Ge-O and Ge<--N bonds in 1-3 were analyzed by the AIM approach. The interactions between the Ge atom and N atoms as well as O atoms possess predominantly ionic character.