Novel highly emissive 2-pyridone-based compounds 3a,b and 4a–d were synthesized by a convenient one-pot method from 4-(dialkylamino)acetophenones (1a,b) and cyanoketene dithioacetal (2a) or sulfonyl ketene dithioacetals (2b,c), and their fluorescence properties were investigated. A simple structure modification of 2-pyridones significantly affected their optical properties including the emission wavelength and fluorescence intensity. All the 6-(4-dialkylamino)phenyl-2-pyridones showed positive solvatofluorochromism and intense blue-green fluorescence in nonpolar solvents such as chloroform (Ф: 0.80–0.92) and dichloromethane (Ф: 0.83–0.94). A hypsochromic shift of the fluorescence emission maxima and strong fluorescence in a polar solvent were observed by substituting the dimethylamino group with a diethylamino group. Introduction of a sulfonyl group disturbed the molecular planarity of compounds 4a, 4b, and 4d, resulting in a strong fluorescence in acetone (Ф: 0.86–0.95) and acetonitrile (Ф: 0.59–0.88). These results indicate that 2-pyridone-based compounds have great potential as fluorophores for various practical applications.

New fluorescent compounds, 2-substituted indeno[1,2-d]pyrimidin-5-ones (3a, 3b, 3c, 3d) were synthesized in good yield by the reaction of 2-[bis(methylsulfanyl)methylene]indan-1,3-dione (1) with the respective amidine derivatives [guanidine carbonate (2a), acetamidine hydrochloride (2b), S-methylisothiourea sulfate (2c), and S-benzylisothiourea sulfate (2d)]. 4-Substituted amino-2-aminoindeno[1,2-d]pyrimidin-5-ones (7b, 7c, 7d) were synthesized by a one-pot reaction of 1, 2a and the respective amine compounds (4b, 4c, 4d) in pyridine. These fused pyrimidine derivatives showed fluorescence in the solid state.

One-pot synthesis of a new 2-pyrone dye (3a) by the reaction of 4-diethylamino-acetophenone (1) with methyl 2-cyano-3,3-bis(methylsulfanyl)acrylate (2) in the presence of sodium hydroxide as the base was carried out in DMSO. Compound 4a was synthesized by the replacement of methylsulfanyl group of 3a with dimethylamine at 4-position of pyrone ring. Similarly, compound 5a was prepared via the reaction of 3a with diethyl malonate. Compounds 3a-5a exhibited the following fluorescence in the solid state: red (3a), green (4a), and orange (5a). In addition, it was revealed that 2-pyrone dyes exhibit fluorescence in various solvents and show positive solvatochromism. Compounds 3a and 5a exhibited intense fluorescence in chloroform and dichloromethane (fluorescence quantum yield Phi: 0.94-0.95). In contrast, compound 4a exhibited intense fluorescence in polar solvents (methanol: Phi = 092). These 2-pyrone dyes have the potential for applications in various fields. (C) 2011 Elsevier Ltd. All rights reserved.

Two new μ-phenoxo/μ-carboxylato-bridged trinuclear nickel(II) complexes,[Ni3(HL1)2(μ2-1,3-CH3CO2)2(urea)2](CH3OH)2 (1) and [Ni3(HL2)2(μ2-1,3-HCO2)2(dmf)2](dmf)2 (2) (H3L1=1,3-bis(salicylideneamino)-2-propanol), H3L2=1,3-bis(5-Br-salicylideneamino)-2-propanol) were prepared and characterized. The X-ray structures analysis of 1 and 2 revealed that three Ni(II) atoms are symmetrically linked by μ-phenoxo/μ-carboxylato bridges to form linear trinuclear complexes. The temperature dependence of magnetic susceptibility measurements show that complexes 1 and 2 have a weak antiferromagnetically coupling. Fit as linear three nuclear arrangement gave parameters of J=−1.70cm−1, g=2.09, and D=1.84cm−1 for 1 and J=−2.78cm−1, g=2.01 and D=3.61cm−1 for 2 respectively.

Four new mononuclear iron(III) complexes with the substituted-salicylaldimine ligands, [Fe(L1)(TCC)] (1), [Fe(L2)(TBC)] (2), [Fe(L3)(TBC)] (3) and [Fe(L4)(TCC)](CH3CN) (4) (HL1=N′-(5-OH-salicylaldimine)-diethylenetriamine, HL2=(N′-(5-Cl-salicylaldimine)-diethylenetriamine, HL3 N′-(5-Br-salicyl-aldimine)-dipropylenetriamine, HL4=(N′-3,5-Br-salicylaldimine)-dipropylenetriamine, H2TCC=tetrachlorocatechol, and H2TBC=tetrabromocatechol), were prepared and characterized by XRD, EPR, and Mössbauer spectroscopy. The kinetic studied on the in situ prepared Fe(III) complexes [HL1+FeCl3], [HL2+FeCl3], [HL3+FeCl3], and [HL4+FeCl3] reaction with 3,5-DTBC (3,5-di-tert-butylcatechol) in the presence of air at pH 7.0 and 25°C exhibit high catecholase activity.

A new μ-alkoxo–μ-6-methoxypurinate double bridged dinuclear copper(II) complex [Cu2(L)(μ-6-meo-pur)(dmf)] (1) (μ-6-meo-pur = μ-6-methoxypurinate, H3L = 1,3-bis(3,5-tert-butyl-salicylideneamino)-2-propanol; dmf = N,N-dimethylformamide) has been prepared and structurally characterized. The single crystal X-ray analysis show that the structure of complexes 1 is dimeric with two adjacent copper(II) atoms double bridged by μ-alkoxo–μ-purinato with the Cu···Cu distances and Cu–O(alkoxo)–Cu angles 3.227(3) Å and 110.30(11)°, respectively. Magnetic measurements reveal that 1 is a ferromagnetically coupled with exchange parameter of 2J = 56.2 cm−1. DFT calculation of spin density of HOMO for 1 was presented.

One mu-alkoxo-mu-carboxylato bridged dinuclear copper(II) complex, [Cu-2(L-1)(mu-C6H5CO2)] (1) (H3L1 = 1,3-bis(salicylideneamino)-2-propanol)), and two mu-alkoxo-mu-dicarboxylato doubly-bridged tetranuclear copper(II) complexes, [Cu-4(L-1)(2)(mu-C8H10O4)(DMF)(2)]center dot H2O (2) and [Cu-4(L-2)(2)(mu-C5H6O4)]center dot 2H(2)O center dot 2CH(3)CN (3) (H3L2 = 1,3-bis(5-bromo-salicylideneamino)-2-propanol)) have been prepared and characterized. The single crystal X-ray analysis shows that the structure of complex 1 is dimeric with two adjacent copper(II) atoms bridged by mu-alkoxo-mu-carboxylato ligands where the Cu center dot center dot center dot Cu distances and Cu-O(alkoxo)-Cu angles are 3.511 angstrom and 132.8 degrees, respectively. Complexes 2 and 3 consist of a mu-alkoxo-mu-dicarboxylato doubly-bridged tetranuclear Cu(II) complex with mean Cu-Cu distances and Cu-O-Cu angles of 3.092 angstrom and 104.2 degrees for 2 and 3.486 angstrom and 129.9 degrees for 3, respectively. Magnetic measurements reveal that 1 is strong anti ferromagnetically coupled with 2J = -210 cm(-1) while 2 and 3 exhibit ferromagnetic coupling with 2J = 126 cm(-1) and 82 cm(-1) (averaged), respectively. The 2J values of 1-3 are correlated to dihedral angles and the Cu-O-Cu angles. Dependence of the pH at 25 degrees C on the reaction rate of oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC) to the corresponding quinone (3,5-DTBQ) catalyzed by 1-3 was studied. Complexes 1-3 exhibit catecholase-like active at above pH 8 and 25 degrees C for oxidation of 3,5-di-tert-butylcatechol.

Two new 1-D silver(I) complexes, [Ag(I)1.5(IM-oBA)(NO3)(0.5)] (1) and [Ag(I)(NIT-pBA)] (2), (IM-oBAH = 2-(2-carboxyphenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-yloxyl, NIT-pBAH = 2-(4-carboxyphenyl)-4,4,5,5-tetramethyl-4,5-dihydro-3-oxido-H-imidazol-3-ium-1-yloxyl) have been prepared and structurally characterized. Complexes I and 2 crystallized in the monoclinic space groups of C2/c and P2(1)/c, respectively. In complex 1, the structure consists of trinuclear Ag(I) atoms with different linkages of IM-oBA and nitrates. The trinuclear Ag(I) atoms are further coordinated to the neighbor IM-oBA radicals via self-assembly of the nitrogen atom of imine moiety and extended into formation of a polymeric chain. Complex 2 is constructed from a bis(carboxylato-O,O')-bridged centrosymmetric dimeric subunit and extended into a polymeric chain through self-assembly coordination between metal ions and nitroxide groups of NIT-pBA radicals. Temperature dependence of magnetic susceptibility measurements showed a weak ferromagnetic coupling between nitroxide radicals in 1 and 2 with J = 5.62 for 1 and 6.62 cm(-1) for 2, respectively.

Syntheses, molecular and supramolecular structures, and magnetic properties of a mononuclear manganese(II) compound [MnII(LH)2](ClO4)2 (1) and a dicyanamide-bridged one-dimensional copper(II) compound [CuII(LH)(μ1,5-dca)]n(NO3)n (2) derived from enolic 4-terpyridone (LH) have been described. The compounds 1 and 2 crystallize in monoclinic P2(1)/n and triclinic P1¯ space groups, respectively, with the following unit cell parameters – 1: a = 8.8281(4) Å, b = 8.7736(4) Å, c = 39.7838(16) Å, β = 95.719(1)°, and Z = 4; 2: a = 7.5342(3) Å, b = 8.9307(4) Å, c = 15.0189(8) Å, α = 73.0032(15)°, β = 81.3701(16)°, γ = 65.461(2)°, and Z = 2. In 1, the metal center is hexacoordinated by three pyridine nitrogens of each of the two enolic 4-terpyridones. In 2, the metal center is pentacoordinated by three pyridine nitrogens of 4-terpyridone and two nitrogens of two end-to-end (EE; μ1,5-) dicyanamide. The coordination geometries of 1 and 2 are distorted octahedral and distorted square pyramidal, respectively. Eight hydrogen bonds, six of C–H⋯O types and two of O–H⋯O types, link the complex cation [MnII(LH)2]2+ and two perchlorate anions into a three-dimensional network in 1. In the case of 2, seven hydrogen bonds, six of C–H⋯O types and one of O–H⋯O type, link the dicyanamide-bridged one-dimensional chains into a two-dimensional sheet consisting of interlinked one-dimensional double-chains. It may be noted that O–H group of enolic 4-terpyridone participates in hydrogen bonding interactions and in developing extended structures in both 1 and 2. Variable-temperature (2–300 K) magnetic susceptibility measurements of both the compounds have been performed to understand the possibility of spin transition in 1 and exchange interaction in 2. However, the susceptibility data of 1 indicate the existence of high-spin manganese(II) throughout the temperature range. In the case of 2, copper(II) centers are noninteracting which is related to the highly distorted coordination geometry of the metal ion.

Two new hetero-tetranuclear complexes, [Sm-2(o-phen)(2)(DMF)(6)(H2O)2(mu-CN)(4)Fe-2 (CN)(8)]center dot 5H(2)O center dot CH3OH (1) and [Sm-2(o-phen)(2)(DMF)(6)(H2O)(2)(mu-CN)(4)Co-2(CN)(8)]center dot 5H(2)O (2), have been prepared from reaction of SmCl3 center dot 6H(2)O, K-3[Fe(CN)(6)]center dot 3H(2)O or K-3[Co(CN)(6)], and o-phen in methanol/DMF, and characterized. The structure of I consists of a cyano-bridged discrete cyclic tetranuclear complex in which the Sm(III) and Fe(III) centers are linked by four CN groups. Mossbauer spectrum of 57 Fe indicates that both Fe(III) atoms in I have the same low-spin (S=1/2) electronic ground state. From comparison of the magnetic data of I and 2, at low temperature for I indicates weak ferromagnetic coupling between Sm(III) and Fe(III).

The reaction of stoichiometric amount of FeCl3, Schiff-base ligand, NaBPh4 in CH3CN and 3,5-DTBC in CH3OH under O2 did produce a new μ-oxo-bridged hexanuclear iron(III) cluster [Fe6(L)2(μ3-O)2(μ-3,5-DTBC)4(μ-CH3O)2(Cl)2] (BPh4)2·2H2O (1) (L=N,N-diethylenetriamino-bis(imidazolaldiminato) with a spin ground state of S=5.

Synthesis, crystal engineering, and magnetic properties of an anionic 4-terpyridone (L) based three-dimensional supramolecule, [Cu2II(L)2(μ1,1-N3)2]·2[CuII(L)(N3)(H2O)]·6H2O (1), have been described in the present investigation. The title compound crystallizes in the monoclinic space group C2/c with the following unit cell parameters: a=27.803(7)Å, b=14.361(4)Å, c=16.071(4)Å, β=99.09(2)°, and Z=4. In this compound, one dinuclear [Cu2II(L)2(μ1,1-N3)2] unit is cocrystallized with two mononuclear [CuII (L)(N3)(H2O)] units. In both the dinuclear and mononuclear species, 4-terpyridone chelates to the metal centers in its anionic form. The coordination environment of the metal ions is distorted square pyramidal. Eight O–H⋯O type strong hydrogen bonds involving the oxygen of anionic 4-terpyridone ligand and water molecules link the components of 1 into a three-dimensional framework. Excluding the atoms except the water molecules and ligand oxygens, the topology is a two-dimensional network. The mononuclear [CuII(L)(N3)(H2O)] moiety is appended from this sheet, while the neighboring sheets are interlinked by the dinuclear [Cu2II(L)2(μ1,1-N3)2] unit to add the third dimension of the overall three-dimensional structure of the title compound.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

A series of mononuclear iron(III) complexes with containing phenolate donor of substituted-salicylaldimine based ligands [Fe(L1)(TCC)]·CH3OH (1), [Fe(L2)(TCC)]·CH3OH (2), [Fe(L3)(TCC)] (3), and [Fe(L4)(TCC)] (4) have been prepared and studied as functional models for catechol dioxygenases (H2TCC=tetrachlorocatechol, or HL1=N′-(salicylaldimine)-N,N-diethyldiethylenetriamine, HL2=N′-(5-Br-salicylaldimine)-N,N-diethyldiethylenetriamine, HL3=N′-(4,6-dimethoxy-salycyl-aldimine)-N,N-diethyl-diethylenetriamine, HL4=N′-(4-methoxy-salicylaldimine)-N,N-diethyl-diethylenetriamine). They are structural models for inhibitors of enzyme-substrate adducts from the reactions of catechol 1,2-dioxygenases. Complexes 1–4 were characterized by spectroscopic methods and X-ray crystal structural analysis. The coordination sphere of Fe(III) atom of 1–4 is distorted octahedral with N3O3 donor set from the ligand and the substrate TCC occupying cis position, and Fe(III) is in high-spin (S=5/2) electronic ground state. The in situ prepared iron(III) complexes without TCC, [Fe(L1)Cl2], [Fe(L2)Cl2], [Fe(L3)Cl2], and [Fe(L4)Cl2] are reactive towards intradiol cleavage of the 3,5-di-tert-butylcatechol (H2DBC) in the presence of O2 or air. The reaction rate of catechol 1,2-dioxygenase depends on the redox potential and acidity of iron(III) ions in complexes as well as the substituent effect of the ligands. We have identified the reaction products and proposed the mechanism of the reactions of these iron(III) complexes with H2DBC with O2.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

A new mu-oxo-bridged Cu(II) complex with cubane-like tetranuclear copper(II) complex, [Cu-4(L-1)(4)]center dot 4H(2)O (1) (H2L1 = 2-(3-methoxysalicylidene-amino)-benzyl-alcohol), has been prepared, and structurally characterized by X-ray crystallography. Complex 1 crystallized in the monoclinic space group P-21/n and has a tetranuclear core Of Cu4O4. The temperature dependence of magnetic susceptibility measurements shown that complex I exhibits a strong antiferromagnetic interaction with J = 103.4 cm(-1). (c) 2007 Elsevier B.V. All rights reserved.

Two new complexes [Co(bipym)(dca)](dca) (1) and [Co(bipym)(dca)](2)(ClO4)(2) (CH3OH).2H(2)O (2) (dca = dicyanamide, bipym = 2,2'-bipyrimidine) have been synthesized and their structuresl magnetically characterized. Complex 1 crystallizes in a monoclinic system P2(1)/n space group, Z = 4, with a = 9.3710(2), b = 15.0690(3), c = 9.8920(2) angstrom, beta = 92.4780(10)degrees. Complex 2 crystallizes in a monoclinic system C2/c space group, Z = 4, with a = 16.4190(3), b = 17.0880(3), c = 12.1130(2) angstrom, and beta = 95.1070 (10)degrees. The crystal structure in 1 and 2 is a three-dimensional network contraction through the bridging 1,5-dca and bipym ligands. Temperature dependence of magnetic measurements show antiferromagnetic couplings in all cases with J = -7.22 for 1, and -7.11 cm(-1) for 2, respectively.

Syntheses, structures, and magnetic properties of two dicyanamide (dca) bridged compounds of manganese(II), [MnII(DMeDPQ)(μ1,5-dca)2]n (1) and [Mn2II(TPT)2(μ1,5-dca)2(H2O)2](ClO4)2(2), have been described (DMeDPQ=6,7-dimethyl-2,3-di(2-pyridyl)quinoxaline; TPT=2,4,6-tri(2-pyridyl)-1,3,5-triazine). While 2 is a discrete dinuclear compound, the structure of 1 is polymeric and consists of one-dimensional double chains. DMeDPQ and TPT behave here as bidentate and tridentate chelating ligands, respectively. The one-dimensional double chain structure in 1 is formed due to the dual existence of two single and two double end to end (μ1,5-, EE) dca ligands. In the case of 2, the metal centers are bridged by two double EE dca ligands. The variable-temperature magnetic susceptibility measurements of both compounds reveal that dicyanamide mediates a weak antiferromagnetic interaction between the metal centers.