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Complexes of new Schiff base ligands generated in situ from the reaction of 1-aminoglycerol, aldehydes, and metal ions are reported. [Cu4(HL1)4] ( 1) and [Ni4O(HL1)3(H2O)3)] ⋅6 H2O ⋅DMF ⋅DMSO ( 2) have M4O4 cubane cores, with the L/M molar ratios of 4:4 and 3:4, respectively. [MnIII3MnIINaOCl4(HL1)3] ⋅3 MeCN ( 3) has a unique pentanuclear trigonal propeller-shaped MnIII3MnIINa core structure, and the coordination assemblies are linked by hydrogen bonds to afford a 3D channel structure. [Cu2(HL2)2] ( 4) has a bis(μ2-alkoxo)-bridged Cu2O2 core, with the binuclear species linked by hydrogen bonds to afford a 1D double-chain. [Ni7(OH)2(OCH3)4(H2L3)2(MeOH)2(H2O)2]- (ClO4)2 ⋅10 H2O ( 5) has a heptanuclear structure containing heptadentate di-Schiff base ligands, with the nickel(II) ions bridged by phenoxo, alkoxo, hydroxo, and methoxo groups to afford a very rare face-sharing hexadruple defective cubane core with a Ni@Ni6 arrangement. The lattice water molecules are linked by hydrogen bonds to form helical chains, which are further hydrogen-bonded to the coordination moieties to afford a 2D network. Variable temperature magnetic susceptibility measurements and nonlinear data-fitting revealed that the '2+4' type of cubane complex 1 shows medium intradimeric ferromagnetic interactions and weak interdimeric ferromagnetic interactions. For complexes 2 and 5, coexistent ferro- and antiferromagnetic couplings afford a non-zero spin ground state. However, compound 3 shows antiferromagnetic interactions between MnIII and MnII, and ferromagnetic interactions between the MnIII centers, resulting in a global antiferromagnetic behavior. In conclusion, the reaction of 1-aminoglycerol with aldehydes and metal salts afforded polynuclear complexes with a rich structural diversity and remarkable magnetic behavior. [ABSTRACT FROM AUTHOR]

[Cu2(H4L)(OCH3)(H2O)] · 2MeOH (1) has been synthesized from the reaction of 2-hydroxy-5-methylisophthalaldehyde, tris(hydroxymethyl)aminomethane and copper(II) perchlorate in methanol with the Schiff-base polyhydroxyl ligand (H4L)3− formed in situ. Single-crystal X-ray structure analysis of 1 reveals a binuclear structure with Cu(II) asymmetrically bridged by a methoxo and a phenoxo group with Cu–O–Cu bridging angles of 102.93(7)° and 100.17(7)°, respectively. The binuclear Cu(II) moieties utilize the coordinated and noncoordinated alkoxyl groups for formation of intermolecular hydrogen bonds, thus affording a 3-D supramolecular structure. Variable temperature magnetic measurements reveal strong antiferromagnetic coupling in 1 with the 2J-value of −729 cm−1, which was mediated cooperatively by the methoxo and phenoxo bridges. Magneto-structural correlations are discussed based on the crystal structure. [ABSTRACT FROM PUBLISHER]

A potentially heptadentate ligand H3L (N,N′-bis(2-hydroxybenzyl)-1,3-bis[(2-aminoethyl)amino]-2-propanol) and its two Ni(II) complexes, [Ni(H2L)H2O](H2O)3ClO4 (1) and [Ni(H2L)(H2O)](H2O)Cl (2) were prepared and characterized. X-ray structural analyses indicate that complex 1 has a distorted octahedral coordination geometry, with four amine N atoms of H2L- defining the equatorial plane, one aqua O atom and one phenoxo O atom of the ligand occupying two axial positions, respectively. The Ni(II) center of 2 has coordination geometry similar to that of 1. IR and electronic spectra of 1 and 2 are in agreement with their crystal structural features. Approximately along the ab plane, 2D supramolecular structure of 1 is assembled through multiple hydrogen bonds between hydroxy groups of the ligands, coordinated and crystal lattice H2O and π–π stacking interactions between adjacent phenyl rings of the ligands, while for that of 2, probably along the a axis, 1D chain structure is also formed by multiple hydrogen bonds, but lack of π–π stacking interactions. [Copyright &y& Elsevier]

A linear pentadentate ligand, N-(2-hydroxyethyl)-N″-(2-hydroxybenzyl)-diethylenetriamine (HL), and its zinc(II) complex were synthesized and characterized by IR spectra, 1H NMR spectra and elemental analyses. By pH potentiometric titration, protonation constants of HL and stability constants of Zn(II) complexation with HL have been determined at 25 ± 0.1°C and I = 0.1 mol/L (KNO3). The kinetics of 4-nitrophenyl acetate (NA) hydrolysis catalyzed by the complex was determined spectrophotometrically at 25 ± 0.1°C and I = 0.1 mol/L (KNO3) in CH3CN (10 % v/v) at pH 7.0–9.04 (50 mmol/L buffers), and the second-order rate constants kc for NA hydrolysis were obtained. The experimental results indicate that Zn···-OR (R = alkyl) is a better nucleophile than Zn···-OAr (Ar = aryl). A good catalysis was realized with a kc value of 8.5 × 10-2 mol-1 · L · s-1 at pH 9.04. [ABSTRACT FROM AUTHOR]

The design and syntheses of porphyrin-basedligands are attractivefor creating coordination assemblies with novel structures and intriguingproperties. In this work, we designed and synthesized a novel porphyrin-basedligand 5,10,15,20-tetrakis(4,4′-dipyridylaminophenylene)porphyrin(TDPAP, H2L) by the introduction of four peripheral 4,4′-dipyridylaminemoieties to a porphyrin platform. Starting from this novel ligand,the protonated form of the ligand H4LCl2·2CH3OH·2H2O (1) and four coordinationpolymers [Mn(III)Mn(II)LCl3(DMF)]n(2), [Cu4L(CH3COO)5(HCOO)(CH3COOH)(H2O)3]n·nCH3COOH·nH2O (3), [Zn3L(CH3COO)4]n(4), and [Cd2H2L(CH3COO)4]n·nDMF·nCH3COOH·2nH2O (5) were synthesized. Single crystal X-ray diffraction analyses revealedthat a rich structural diversity was observed for these compoundsdue to the coordination of the multiple peripheral pyridines as wellas the porphyrin core. 1displays a hydrogen bonded one-dimensional(1D) structure composed of [(H2O)2Cl2]2–moieties. Complex 2shows interpenetratedtwo-dimensional (2D) coordination networks, which are further linkedby π···π stacking interactions to afforda three-dimensional (3D) structure. 3shows a 2D sheetcomposed of 50- and 70-membered metallomacrocycles. In complex 4, 1D zigzag coordination chains were generated and furtherlinked to form a 2D structure. Complex 5has a stairlike2D structure formed by the linkage of 1D coordination chains throughthe bridging of binuclear [Cd2(CO2)4] subunits. In these compounds, TDPAP shows a unique coordinationbehavior. It may bind 4–7 metal centers, and it demonstratesconformational flexibility and the ability to form intermolecularhydrogen bonds and π···π interactions,which contribute to the formation of novel supramolecular structures.On the basis of the novel structures, the solid state emissions ofthe compounds were also investigated. [ABSTRACT FROM AUTHOR]

The design and syntheses of novel ligands are essentialfor developingcoordination compounds with novel structures and interesting properties.In this work, we designed and synthesized a novel ligand bis(4,4′-dipyridylaminophenylene)butadiyne(L) by attaching two 4,4′-dipyridylamine moietiesto a flexible butadiyne linker. Starting from this novel ligand, sevencoordination polymers [Zn2L(HCOO)3(OH)]n(1), [Cd2L2Cl4]n·3nDMF·3nH2O (2), [CdLBr2]n(3), [Cd6L3(SO4)6]n·4nMeCN (4), [Hg2LBr4]n·3nCH2Cl2·nH2O (5), [Cu2LI2]n·0.5nCH2Cl2(6), and [Ag2L(H2O)2]n(NO3)2n·2nH2O (7) were synthesized.Single-crystal X-ray diffraction analyses revealed that two formsof the ligand crystals, Land L·0.5DMFpresent straight and bent conformations, respectively, because ofthe flexibility of the butadiyne unit. A rich structural diversitywas observed for its d10metal complexes. Complexes 1and 5present ladder-like structures. In complexes 2and 4, the ligand molecules are linked by metalatoms to afford 3D supramolecular structures. It is noteworthy thatthe 3D structure of complex 4consists of interestinginfinite {Cd6(SO4)6}∞chains, whereas complexes 3, 6, and 7exhibit 2D network structures. Interestingly, in the crystalof complex 7, each ligand links four metal ions and eachAg ion bridges two ligands, leading to the formation of undulated2D sheets with large cavities composed of 66-membered metallomacrocycles,which are interpenetrated by three other such 2D sheets, affordinga 4-fold interpenetrated structure. In summary, the complex structuresare dependent on the metal ions and the anions. In addition, the flexibilityof the butadiyne moiety provides additional means for modulating thestructures. Solid state photoluminescence of the free ligand and thecomplexes shows emission maxima within the range of 420–515nm, which can be modulated by the conformations of the ligand in additionto the variation of the metal ions and anions, and the introductionof the butadiyne unit has a bathochromic effect. [ABSTRACT FROM AUTHOR]

In situ formation of ligands is an efficient approachto synthesizingnovel complexes with unique coordinating moieties. Oxazolidines andoxazinanes are 1,3-N,O-containing five-membered and six-membered heterocycles,respectively. Metal complexes of ligands derived from these two heterocyclesare rather rare. In this work, we designed and synthesized a novelmultihydoxy ligand, 2-((2,3-dihydroxypropylamino)methyl)phenol (H3L1). It contains both aminoethanol and aminopropanolunits, which may be employed to react with aldehydes to afford oxazolidinesand oxazinanes, respectively. Thus, H3L1wasreacted with metal salts in the absence or presence of aldehydes toafford complexes [Cu(HL1)]2(1),[CuL2]4·4CH3OH (2) [Zn5Na2(L3)4(DMSO)2.65(DMF)1.35]·DMF (3), and [Ni(HL4)]2(4). Complex 1is a dialkoxo-bridged binuclear Cu(II) complex. The coordinationmoieties are linked by intermolecular C–H···Ohydrogen bonds to afford a 1D double-chain supramolecular structure.Interestingly, in complexes 2–4,H3L1has been reacted with formaldehyde, salicylaldehyde,and 2,6-diformyl-4-cresol to afford novel ligands H2L2, H3L3, and H3L4, respectively. The combination of in situ formed oxazinane or oxazolidinerings with appended alkoxyl and phenol functionalities in these ligandshas been demonstrated to form a rich diversity of coordination structures.Thus, 2is a tetranuclear Cu(II) complex with a face-sharingdouble defective cubane core structure. In this complex, (L2)2–ligands coordinate in two different bridgingmodes with the Harris notations of 3.1121221311and 3.1131231111, respectively. Complex 3has an interestingheptanuclear Zn5Na2core structure. A centralZn(II) is coordinated with four alkoxo O atoms from four (L3)3–ligands. Each of the O atom further bridgesanother Zn(II) atom, resulting in a Zn5moiety, which isthen connected to two Na phenoxo O bridges, finallyaffording the Zn5Na2core. The bridging modeof (L3)3–can be designated as 4.21221311312411.And Complex 4is a binuclear Ni(II) complex containingdi-μ2-phenoxo bridges. The coordination moietiesare linked by intermolecular C–H···π,C–H···O, and π···πinteractions to afford a two-dimensional supramolecular network. Theseresults indicate that the combination of in situ formed oxazinaneand oxazolidine rings with appended phenol and alkoxyl functionalitiesis an efficient approach to developing novel ligands and complexeswith a rich structural diversity. Variable temperature magnetic datameasurements revealed that medium antiferromagnetic interaction existsbetween the Cu(II) centers in complex 1with a −2Jvalue of 278 cm–1. And in complex 4, weak antiferromagnetic coupling occurs between the Ni(II)centers, with a −2Jvalue of 9.36 cm–1. [ABSTRACT FROM AUTHOR]