Syntheses,crystal structures,and photoluminescence of two Cd(II) complexes with simple ligands

Two cadmium complexes, {[Cd₂(2,5-tda)₂(ip)₄]·4H₂O}_n (1) and {[Cd₂(4,4′-obb)₂(ip)₂·H₂O]·H₂O}_n (2) (2,5-tda?=?thiophene-2,5-dicarboxylic acid, 4,4′-obb?=?4,4′-oxybisbenzoic acid, ip?=?1H-imidazo[4,5-f][1, 10]-phenanthroline), were synthesized and characterized by IR, elemental analysis, powder X-ray diffraction, and single-crystal X-ray diffraction. X-ray analysis revealed that 1 is a dinuclear complex with the 2,5-tda anion connecting two Cd ions in a μ₁-η¹:η⁰/μ₁-η¹:η⁰ coordination mode. Each dinuclear complex is further connected with neighboring complexes via hydrogen-bonding interactions. Compound 2 displays a 2-D layer structure with opened windows occupied by crystallographic water molecules. The layers are further packed via hydrogen-bonding interactions. Luminescent properties for 1 and 2 are also investigated in the solid state at room temperature.     

Syntheses,structures, and photoluminescence of three cadmium(II) coordination polymers with flexible bis(benzimidazole) ligands

Three cadmium(II) coordination polymers, [CdBr₂(L₁)] _n (1), [CdI₂(L₂)] _n (2), and Cd₂Br₄(L₃)₂ (3), where L₁?=?1,3-bis(5,6-dimethylbenzimidazole)propane, L₂?=?1,4-bis(5,6-dimethylbenzimidazole)butane, and L₃?=?1,6-bis(5,6-dimethylbenzimidazole)hexane, have been synthesized by hydrothermal methods and characterized by elemental analyses, IR spectra, TGA, PXRD, and X-ray crystallographic diffraction. Complex 1 contains a 1-D helical chain in which CdBr₂ units are linked by L₁. For 2, each CdI₂ is connected by two different conformations of L₂ to form a 1-D zigzag chain. For 3, each CdBr₂ is linked by L₃ bridges to afford a binuclear structure. These results indicate that the spacer length of the ligands play important roles in assembly of Cd(II) coordination polymers. Thermogravimetric analyses and solid-state luminescent properties of the complexes have also been investigated.     

Syntheses, structures, and photoluminescence properties of metal(II) halide complexes with pyridine-containing flexible tripodal ligands

Seven coordination compounds, [Zn(L3)Cl2] . MeOH . H2O (1), [Mn(L3)2Cl2] . 0.5EtOH . 0.5H2O (2), [Cu3(L2)2Cl6] . 2DMF (3), [Cu3(L2)2Br6] . 4MeOH (4), [Hg2(L4)Cl4] (5), [Hg2(L4)Br4] (6), and [Hg3(L4)2I6] . H2O (7), were synthesized by the reactions of ligands 1,3,5-tris(3-pyridylmethoxyl)benzene (L3), 1,3,5-tris(2-pyridylmethoxyl)benzene (L2), and 1,3,5-tris(4-pyridylmethoxyl)benzene (L4) with the corresponding metal halides. All the structures were established by single-crystal X-ray diffraction analysis. In complexes 1 and 2, L3 acts as a bidentate ligand using two of three pyridyl arms to link two metal atoms to result in two different 1D chain structures. In complexes 3 and 4, each L2 serves as tridentate ligand and connects three Cu(II) atoms to form a 2D network structure. Complexes 5 and 6 have the same framework structure, and L4 acts as a three-connecting ligand to connect Hg(II) atoms to generate a 3D 4-fold interpenetrated framework, while the structure of complex 7 is an infinite 1D chain. The results indicate that the flexible ligands can adopt different conformations and thus can form complexes with varied structures. In addition, the coordination geometry of the metal atom and the species of the halide were found to have great impact on the structure of the complexes. The photoluminescence properties of the complexes were investigated, and the Zn(II), Mn(II) and Hg(II) complexes showed blue emissions in solid state at room temperature.     

Syntheses, structures, photoluminescence and theoretical studies of xanthone in crystalline resorcinarene-based inclusion complexes

Two new crystalline resorcinarene-based xanthone inclusion complexes, CECRxanthoneMeOH (1), and HECR2 xanthone6 MeOH (2) (CECR = C-ethylcalix[4]resorcinarene, HECR = hexaethylresorcin[6]arene) have been prepared to study the relation between photophysical properties and solid-state structure. Compared with the neat crystals, the xanthone phosphorescence is severely quenched in both solids, but the lifetime is an order of magnitude larger in 2, in which xanthone occurs as a dimer, than in 1, in which it occurs as a monomer. The electronic transitions involved in the photoluminescent process, and the relation between the energy levels of host and guest and emission quenching of the guest in the supramolecular solid have been investigated by means of time-dependent density functional theory (TDDFT) calculations.     

Synthesis,structure and olefin polymerization catalysis of nickel(II) complexes bearing N,O-chelate ligands

Four β-ketoimine ligands (two series) were prepared through traditional condensation reactions of β-diketones with 2,6-substituted anilines. Reaction took place only at the cyclohexanone carbonyl rather than at the acetyl or benzoyl carbonyl, even if more than two equivalents of the amines were added. Consequently, four new moisture- and air-stable bis(β-ketoamino)nickel(II) complexes, Ni[2–CH₃C(O)C₆H₈(=NAr)]₂ (Ar?=?2, 6-iPr₂C₆H₃, (1); Ar?=?2, 6-Me₂C₆H₃, (2) and Ni[2–PhC(O)C₆H₈(=NAr)]₂ (Ar?=?2, 6-iPr₂C₆H₃, (3); Ar?=?2, 6-Me₂C₆H₃, (4) were obtained and characterized. The solid-state structures of complex 1, 2 and 3 have been determined by single-crystal X-ray diffraction. Additionally, these complexes can be applied as highly active catalyst precursors for vinyl polymerization of norbornene (NBE) after activation with methylaluminoxane (MAO).     

Syntheses,structures, photoluminescence,and theoretical studies of a novel class of d10 metal complexes of 1H-[1,10]phenanthrolin-2-one

A novel asymmetric monosubstituted 1,10-phenanthroline, Hophen.0.5 H(2)O (1, Hophen=1H-[1,10]phenanthrolin-2-one), was generated by a facile route, and a novel class of crystalline, d(10)-metal, monomeric or oligomeric complexes of this ligand, namely [Hg(ophen)(2)].4 H(2)O.CH(2)Cl(2) (2), [Cd(3)Cl(ophen)(5)].1.5 H(2)O.2 CH(2)Cl(2) (3), and [Zn(4)O(ophen)(4)(OAc)(2)].4H(2)O.2 CH(2)Cl(2) (4), were obtained by means of liquid diffusion, and were characterized by X-ray crystallography and photoluminescence studies. Complex 1 exhibits a hydrogen-bonded dimeric structure, 2 is a neutral monomeric complex, 3 has a trinuclear structure with the ophen ligand acting as a bridge through the ketone groups, and 4 features a tetranuclear Zn(4)O core that is consolidated further by bridging ophen and acetate ligands. All the complexes display photoluminescent properties in the blue/green region. The photoluminescent mechanisms were investigated by means of molecular orbital calculations, which showed that the photoluminescent properties are ligand-based and can be tuned upon ligation to different metal ions.     

Synthesis,structures, photoluminescence,and theoretical investigations on two new Zn(II)/Mn(II) complexes with pyridine-2-amidoxine and carboxylate ligands

Abstract  

Two new neutral mononuclear Zn(II) and Mn(II) complexes with pyridine-2-amidoxine and carboxylate ligands, [Zn(paH)₂(OAc)₂]·2CH₃OH (paH = pyridine-2-amidoxine, HOAc = acetic acid) (1), and [Mn(paH)₂(OAc)₂]·C₂H₅OH·2H₂O (2), have been prepared and characterized structurally by X-ray crystallography. 1 and free paH exhibit photoluminescence at room temperature in solid state, which is rare so fare for metal complexes with oxime-based ligand. The emissions of 1 and free paH arise from the metal-perturbed paH-based π → π* ligand-to-ligand charge transfer transition (LLCT) and π → π* charge transfer transition in nature, respectively, in terms of the density functional theory level calculations and molecular orbital analyses.     

Syntheses, structures and catalytic activity of copper(II) complexes with hydroxyindanimine ligands

A series of new hydroxyindanimine ligands [ArNCC₂H₃(CH₃)C₆H₂(R)OH] (Ar = 2,6-i-Pr₂C₆H₃, R = H (HL¹), R = Cl (HL²), and R = Me (HL³)) were synthesized and characterized. Reaction of hydroxyindanimine with Cu(OAc)₂ · H₂O results in the formation of the mononuclear bis(hydroxyindaniminato)copper(II) complexes Cu[ArNCC₂H₃(CH₃)C₆H₂(R)O]₂ (Ar = 2,6-i-Pr₂C₆H₃, R = H (1), R = Cl (2), and R = Me (3)). The complex 2′ was obtained from the chlorobenzene solution of the complex 2, which has the same molecule formula with the complex 2 but it is a polymorph. All copper(II) complexes were characterized by their IR and elemental analyses. In addition, X-ray structure analyses were performed for complexes 1, 2, and 2′. After being activated with methylaluminoxane (MAO), complexes 1-3 can be used as catalysts for the vinyl polymerization of norbornene with moderate catalytic activities. Catalytic activities and the molecular weight of polynorbornene have been investigated for various reaction conditions.     

Syntheses, structures, photoluminescence, and theoretical studies of d(10) metal complexes of 2,2'-dihydroxy-[1,1']binaphthalenyl-3,3'-dicarboxylate

The free solvated ligand, H(2)bna.CH(3)OH.H(2)O (1), and its dimeric complex, [Cd(2)(bna)(2)(H(2)O)(6)] (2) (bna = 2,2'-dihydroxy-[1,1']-binaphthalene-3,3'-dicarboxylate), were obtained by evaporation of the solutions, while two new d(10) metal-hydroxy cluster-based coordination polymers, namely [Cd(8)(OH)(4)(H(2)O)(10)(bna)(6)].17H(2)O (3) and [Hpy](2)[Zn(4)(OH)(2)(H(2)O)(2)(bna)(4)].2H(2)O.2CH(3)CN (4), were obtained by a hydrothermal route. All the compounds have been characterized by X-ray crystallography and photoluminescence measurements. Compound 1 consists of a three-dimensional, hydrogen-bonded supramolecular array, 2 exhibits a dimeric molecule featuring a square motif organized by two Cd(II) atoms and two bna ligands each at the corner, and 3 contains unprecedented [Cd(8)(micro(3)-OH)(2)(micro-OH)(2)(micro-H(2)O)(2)](12+) octanuclear metallacrown cores which are interlinked through bna to afford a two-dimensional structure, while 4 features layers with butterfly-shaped [Zn(4)(micro(3)-OH)(2)](6+) clusters. All the complexes display photoluminescent properties in the blue/green range. The manifestation of photoluminescence, as probed by molecular orbital calculations performed on the complexes and also on hypothetical multinuclear complexes, is attributed to a ligand-to-metal charge-transfer mechanism. In addition to presenting a new approach for the study of the photoluminescent properties of metal-cluster-based coordination polymers by using simple model compounds, the study also reveals the dominant role of the structure of the ligand over that of the d(10) metal-hydroxy (or oxy) cluster and the presence of the cluster significantly increasing the emission lifetime.     

Structural and spectral studies of palladium(II) and platinum(II) complexes derived from N,N,N,N-tetradentate macrocyclic ligands

Palladium(II) and platinum(II) complexes having the general composition [M(L)] X2 (where M=Pd(II) and Pt(II), L=3,4,12,13-tetraphenyl-2,5,11,14,19,20-hexaaza tricyclo [13.3.1.1.(6-10)] cosa-1(19), 2,4,6,8,10,(20),11,13,15,17-decaene (L1); 3,4,13,14-tetraphenyl-2,5,12,15-tetraaza tricyclo [11,0,0,(6-11)] cosa-1(16),2,4,7,9,6(11),12,14,17, 19-decaene (L2); 2,3,8,9-tetraphenyl-1,4,7,10-tetraaza cyclododeca-1,3,7,9-tetraene (L3) and X=Cl(-)) have been synthesized. The ligands were characterized on the basis of elemental analyses, IR, 1H NMR and EI mass spectral studies while that of the complexes were characterized on the basis of elemental analyses, molar conductance measurements, magnetic susceptibility measurements, IR, and electronic spectral techniques. All the complexes were found to be diamagnetic. The structures consist of monomeric units in which the Pd(II) and Pt(II) atoms exhibit square planar geometry.     

Syntheses, structures, and magnetic properties of inorganic-organic hybrid cobalt(II) phosphites containing bifunctional ligands

Seven new cobalt(II) phosphites, [Co(HPO(3))(C(14)H(14)N(4))(H(2)O)(2)].2H(2)O (1), [Co(HPO(3))(C(22)H(18)N(4))].H(2)O (2), [Co(2)(HPO(3))(2)(C(22)H(18)N(4))(2)H(2)O].H(2)O (3), [Co(2)(HPO(3))(2)(C(12)H(10)N(4))(1.5)H(2)O].1.5H(2)O (4), [Co(HPO(3))(C(14)H(14)N(4))(0.5)].H(2)O (5), [Co(HPO(3))(C(18)H(16)N(4))(0.5)] (6), and [Co(HPO(3))(C(18)H(16)N(4))(0.5)] (7) were synthesized in the presence of 1,2-bis(imidazol-1-ylmethyl)benzene (L1), 1,4-bis(benzimidazol-1-ylmethyl)benzene (L2), 1,3-bis(benzimidazol-1-ylmethyl)benzene (L3), 1,4-bis(1-imidazolyl)benzene (L4), 1,4-bis(imidazol-1-ylmethyl)benzene (L5), 1,4-bis(imidazol-1-ylmethyl)naphthalene (L6), and 1,5-bis(imidazol-1-ylmethyl)naphthalene (L7), respectively, and their structures were determined by X-ray crystallography. Compound 1 is a molecular compound in which two cobalt(II) ions are held together by double mu-O linkages. The inorganic framework of compounds 2 and 3 are composed of vertex-shared CoO(2)N(2)/CoO(3)N(2) and HPO(3) polyhedra that form four rings; these are further linked by an organic ligand to generate 2D sheets. Compounds 4 and 5 both have 1D inorganic structures, with the bifunctional ligands connected to each side of the ladder by coordination bonds to give 2D hybrid sheets. A 3D organically pillared hybrid framework is observed in 6 and 7. In 6, the stacking of the interlayer pillars gives rise to a small hydrophobic channel that extends through the entire structure parallel to the sheets. The temperature-dependent magnetic susceptibility measurements of these compounds show weak interactions between the metal centers, mediated through the mu-O and/or O-P-O linkages.     

Aminoalkylbis(phenolate) [O,N,O] donor ligands for uranyl(VI) ion coordination: Syntheses,structures, and extraction studies

The syntheses of five new aminoalkylbis(phenolate) ligands (as hydrochlorides) and their uranyl complexes are described. The reaction between uranyl nitrate hexahydrate and phenolic ligand [(N,N-bis(2-hydroxy-5-tert-butyl-3-methylbenzyl)-1-aminopropane) · HCl], H₂L1 · HCl, forms a uranyl complex [UO₂(HL1)₂] · 2CH₃CN (1). The ligand [(N,N-bis(2-hydroxy-5-tert-butyl-3-methylbenzyl)-1-aminobutane) · HCl], H₂L2 · HCl, forms a uranyl complex with a formula [UO₂(HL2)₂] · 2CH₃CN (2). The ligand [(N,N-bis(2-hydroxy-5-tert-butyl-3-methyl benzyl)-1-aminohexane) · HCl], H₂L3 · HCl, yields a uranyl complex with a formula [UO₂(HL3)₂] · 2CH₃CN (3) and the ligand [(N,N-bis(2-hydroxy-5-tert-butyl-3-methylbenzyl)-cyclohexylamine) · HCl], H₂L4 · HCl, yields a uranyl complex with a formula [UO₂(HL4)₂] (4). The ligand [(N,N-bis(2-hydroxy-5-tert-butyl-3-methylbenzyl)-benzylamine) · HCl], H₂L5 · HCl, forms a uranyl complex with a formula [UO₂(HL5)₂] · 2MeOH (5). The molecular structures of 1, 2′ (2 without methanol), 3, 4 and 5 were verified by X-ray crystallography. The complexes 1–5 are neutral zwitterions which form in a molar ratio of 1:2 (U to L) in the presence of a base (triethylamine) and bear similar mononuclear, distorted octahedral uranyl structures with the four coordinating phenoxo ligands forming an equatorial plane and resulting in a centrosymmetric structure for the uranyl ion. In uranyl ion extraction studies from water to dichloromethane with ligands H₂L1 · HCl–H₂L5 · HCl, the ligands H₂L2 · HCl and H₂L4 · HCl are the most effective ones.     

Lanthanide-organic frameworks constructed from multi-functional ligands: Syntheses, structures, near-infrared and visible photoluminescence properties

A series of multi-functional ligands supported lanthanide-organic frameworks, formulated as [Ln(HL₁)(H₂L₂)_0.5(H₄L₂)_0.5(H₂O)]·(H₂O)_1.5·{Ln=La (1), Pr (2), Nd (3), Sm (4), Eu (5); H₃L₁=5-Sulfosaclicylic acid; H₄L₂=N,N′-piperazine (bis-methylene phosphonic acid)}, have been synthesized by hydrothermal reactions. Single crystal X-ray diffractions and powder XRD patterns confirm they are isostructural. They feature 3D framework structures based on extension of a “zigzag” inorganic chain by organic linkers. Moreover, the photoluminescence properties of 5 and 3 have been investigated, and they show strong solid-state emissions in the visible and near-infrared (IR) regions at room temperature.     

Novel nickel(II) and copper(II) complexes with phenoxy-imidazole ligands: Syntheses, crystal structures and norbornene addition polymerization

The novel nickel(II) (1) and copper(II) (2) complexes bearing 2′-(4′,6′-di-tert-butylhydroxy-phenyl)-1,4,5-triphenyl imidazole ligand have been synthesized and characterized. The molecular structure analyses of complexes 1 and 2 indicated that Ni(II) centre in 1 adopts a distorted tetrahedral coordination geometry with a dihedral angle of 85.2° between Ni(1)O(1)N(1) plane and Ni(1)O(1A)N(1A) plane, while the Cu(II) centre in 2 represents a distorted square planar coordination geometry with a cis-N₂O₂ arrangement of the donor atoms, the dihedral angle being 32° between Cu(1)O(1)N(1) plane and Cu(1)O(1A)N(1A) plane. After activation with methylaluminoxane (MAO), both Ni(II) and Cu(II) complexes can be used as catalysts for the addition polymerization of norbornene (NB). The polynorbornenes (PNBs) are produced with very high polymerization activity (10⁸ g PNB mol⁻¹ Ni h⁻¹) for Ni(II) complex and moderate catalytic activity (10⁵ g PNB mol⁻¹ Cu h⁻¹) for Cu(II) complex, respectively. The high molecular weight polynorbornenes (10⁶) are obtained for complexes 1 and 2. Moreover, the distinct effects of polymerization temperature and Al/M ratio on catalytic activities and molecular weights of polymers are discussed.     

Syntheses, crystal structures, photophysical and theoretical studies of 1,3,2-benzodiazaborolyl-functionalized diphenylacetylenes

A series of diphenylacetylenes with one 1,3,2-benzodiazaborolyl end group (BDB) and a second end group X (X = H, OMe, NMe(2), SMe, CN and BDB) were synthesized using established 1,3,2-benzodiazaborole methodologies. The 1,3,2-benzodiazaborolyldiphenylacetylenes with X = p-H (4), p-OMe (5), p-NMe(2) (6), p-SMe (7) and p-CN (8) end groups are functionalized with cyano groups at the central ring in an ortho-position to the triple bond. Molecular structures of 2, 3, 5, 6 and 7 were determined by X-ray diffraction. These borylated systems show intense blue luminescence in cyclohexane, toluene, chloroform, dichloromethane and tetrahydrofuran, whereas green luminescence was observed in acetonitrile solutions. Thereby Stokes shifts in the range 1700-8600 cm(-1) and quantum yields of 0.60-1.00 were observed in cyclohexane solutions. The absorption maxima (308-380 nm) are well reproduced by TD-DFT computations (B3LYP/G-311G(d,p)) and arise from strong HOMO-LUMO transitions. The LUMOs in all the molecules under study are mainly located on the diphenylacetylene bridge, while with the exception of the dimethylamino derivative 6, the HOMO is largely benzodiazaborolyl in character. Thus, the S1←S0 absorption bands are assigned to π(diazaborolyl)-π*(diphenylacetylene) transitions. In contrast to this, in compound 6 the HOMO is mainly represented by the terminal dimethylaminophenyl unit. While calculated ground state dipole moments μ(g) are small (1.1-7.5 D), experimentally determined changes of the dipole moments upon excitation are large (14.8-19.7 D) and reflect a significant charge transfer upon excitation. NLO activities of the rod-structured compounds 2, 4, 6 and 8 are indicated by calculated static first-order hyperpolarizabilities β up to 76.8 × 10(-30) esu.     

Syntheses,characterization, and crystal structures of ruthenium(II)/(III) complexes with tridentate salicylaldiminato ligands

Treatment of [Ru(PPh₃)₃Cl₂] with one equivalent of tridentate Schiff base 2-[(2-dimethylamino-ethylimino)-methyl]-phenol (HL) in the presence of triethylamine afforded a ruthenium(III) complex [RuCl₃(κ²-N,N-NH₂CH₂CH₂NMe₂)(PPh₃)] as a result of decomposition of HL. Interaction of HL and one equivalent of [RuHCl(CO)(PPh₃)₃], [Ru(CO)₂Cl₂] or [Ru(tht)₄Cl₂] (tht = tetrahydrothiophene) under different conditions led to isolation of the corresponding ruthenium(II) complexes [RuCl(κ³-N,N,O-L)(CO)(PPh₃)] (2), [RuCl(κ³-N,N,O-L)(CO)₂] (3), and a ruthenium(III) complex [RuCl₂(κ³-N,N,O-L)(tht)] (4), respectively. Molecular structures of 1·CH₂Cl₂, 2·CH₂Cl₂, 3 and 4 have been determined by single-crystal X-ray diffraction.     

Synthesis and structures of copper(II) and cadmium(II) compounds based on pyridazine derivative ligands

The two new compounds [Cu(HODA)₂(H₂O)₂] · 3H₂O (I) and [Cd(HODA)₂(H₂O)₃] (II) (HODA = 6-oxo-1,6-dihydropyridazine-4-carboxylic acid) based on pyridazine derivation ligands have been synthesized and characterized by elemental analysis, infrared spectrum and X-ray single crystal diffraction. X-ray analysis shows that in compound I, Cu²⁺ ion is four-coordinated with a plane square geometry while Cu²⁺ ion in compound II is seven-coordinated with a distorted pentagonal bipyramid geometry. Both of the two units are all connected as 3D supramolecular structures by the intermolecular hydrogen bonds. Moreover, thermal gravimetric analysis of two compounds has been also investigated.     

Two cadmium compounds with adenine and carboxylate ligands: syntheses,structures and photoluminescence

Two cadmium(II) coordination compounds, [Cd₃(CH₃CO₂)₄(ad)₂(CH₃CN)₂]_n (1) and [Cd₃(5-SIP)₂(H-ad)₂(H₂O)₆]_n (2) (H-ad = adenine and 5-SIP = 5-sulfoisophthalate), were synthesized and characterized. Compound 1 features a two-dimensional (2-D) layered structure based on linear trinuclear [Cd₃(CH₃CO₂)₄] units bridged by monoanionic adenine ligands. In 2, the 5-SIP^3? ligands link Cd(II) ions to form a one-dimensional (1-D) ladder, which is further linked by neutral adenine ligands to give a 2-D layered structure. In both structures, the carboxylate ligands link Cd(II) ions to form low-dimensional structures, which are further connected by adenine ligands to give high-dimensional structures. Compounds 1 and 2 exhibit emissions centered at 382 and 416 nm, respectively, which can be attributed to the ligand centered π–π* transition.