Molecular Magnets Based on Mononuclear Aqua and Aqua-Chloro Lanthanide (Tb,Dy, Er,Yb) Complexes with Bipyridine

Russian Journal of Coordination Chemistry - The complexes [Tb(Bipy)2(H2O)2Cl2]Cl (I), [Ln(Bipy)(H2O)6]Cl3·2H2O·0.5Bipy (Ln = Dy (II), Yb (IV)), [Er(Bipy)2(H2O)3Cl]Cl2·2H2O (III), and...     

Anion dependant self-assembly and the first X-ray structure of a neutral homoleptic lanthanide salen complex Tb4(salen)6

Reaction of H(2)salen (H(2)L) with Tb(OAc)(3).4H(2)O (3 : 2) in MeOH-MeCN under reflux gave homoleptic Tb(4)L(6) (1) in 40% yield; in contrast, similar reactions of Tb(NO(3))(3).6H(2)O and LnCl(3).6H(2)O (Ln = Tb, Nd and Yb) gave [TbL(NO(3))(MeOH)](2)(micro-H(2)L) (2) and [LnL(Cl)(MeOH)](2)(micro-H(2)L) (Ln = Tb (3), Nd (4) and Yb (5); H(2)L = N,N'-ethylenebis(salicylideneimine)).     

Predictable self-assembled [2×2] Ln(III)4 square grids (Ln = Dy,Tb)-SMM behaviour in a new lanthanide cluster motif

The ditopic carbohydrazone ligand (L1) produces the square, self-assembled [2×2] grids [Dy(4)(L1)(4)(OH)(4)]Cl(2) (1) and [Ln(4)(L1)(4)(μ(4)-O)(μ(2)-1,1-N(3))(4)] (Ln = Dy (2), Tb (3)), with 2 exhibiting SMM behaviour. Two relaxation processes occur with U(eff) = 51 K, 91 K in the absence of an external field, and one with U(eff) = 270 K in the presence of a 1600 Oe optimum field.     

Group I cation templated formation of luminescent mono- and bis-substituted thionaphthol heterobimetallic complexes of Pr, Nd, Eu and Tb

Metathesis of lanthanide tris di-tert-butyl beta-diketonates ([Ln(thd)3] Ln=Pr, Nd, Eu, Tb) with one or two equivalents of group 1 salts of the sulfur bridged binaphtholate dianion [1,1'-S(2-OC10H4But(2)-3,6)2]2-, [M2L], M=K, Li affords luminescent mono- and bis-ligand substituted complexes ML[LnL(thd)2].L; M=K, Ln=Pr , Nd , Eu and Tb (L=thf, diethyl ether or toluene) and M(thf)2[LnL2(thd)]; M=Li, Ln=Pr , Nd , Eu , Tb . The potassium salt [K2L] affords mono-L substituted complexes most cleanly, while the lithium salt [Li2L] yields the bis-L substituted complexes most cleanly. The L ligands function as antenna for the sensitised lanthanide-centred emission in Eu3+ and Tb3+ complexes. The X-ray single-crystal structures of mono- and bis-L lanthanide complexes of Nd3+ are presented.     

[Eu（Bipy）2]Cl3和[Tb（Bipy）2]Cl3在有机功能化剥层水滑石表面上的组装及光致发光性质

以乙酰基丙氨基三乙氧基硅烷对剥层镁铝水滑石进行了表面硅烷化修饰,得到了表面硅烷化修饰的剥层水滑石复合材料.然后在该复合材料表面进行了[Eu(Bipy)2]3+和[Tb(Bipy)2]3+分子组装,得到了剥层水滑石复合稀土发光体.组装体的紫外激发发射光谱表明,稀土配合物被组装到经硅烷化试剂修饰的剥层水滑石表面后,其电偶极跃迁较原配合物有很大提高,热稳定性也有提高.从主客体材料相互作用角度对稀土配合物电偶极跃迁的提高进行了解释.     

Constructing terbium co-ordination polymers of 4,4'-bipyridine-N,N'-dioxide by means of diffusion solvent mixtures

Five different co-ordination polymers of terbium(III) and the bidentate ligand 4,4'-bipyridine-N,N'-dioxide (L), [Tb(L)(CH(3)OH)(NO(3))(3)](infinity) (1), ([Tb(L)(1.5)(NO(3))(3)].CH(2)Cl(2))(infinity) (2), ([Tb(L)(1.5)(NO(3))(3)].CH(3)OH.0.8H(2)O)(infinity) (3), ([Tb(L)(1.5)(NO(3))(3)].0.4C(2)Cl(4).0.8CH(3)OH)(infinity) (4), and [Tb(L)(2)(NO(3))(3)](infinity) (5) have been synthesised by the use of different "diffusion solvent mixtures", and structurally characterised by X-ray crystallography. Compound 1, with a Tb:L stoichiometry of 1:1, adopts a zig-zag chain structure, which forms three-fold interpenetrating diamondoid frameworks through interchain hydrogen bonding between co-ordinated methanol and a nitrate group on an adjacent chain. Polymers 2, 3, and 4 all have a Tb:L stoichiometry of 1:1.5, but adopt different topologies. For 2, a ladder arrangement is found and large channels which accommodate solvent CH(2)Cl(2) molecules are formed by superposition of the ladders. For 3 and 4 4.8(2) net structures are observed. The superposition of the 4.8(2) nets in 3 and 4, by disposing adjacent layers such that every octagon is positioned below a tetragon from the neighbouring layer, allows the formation of two kinds of channel, with that inside the tetragons accommodating methanol molecules. The other kind of channel, between tetragons, accommodates water molecules in the case of 3 and tetrachloroethylene molecules in the case of 4. Compound 5, with a Tb:L stoichiometry of 1:2, has a linear polymeric structure with one bridging and one terminal ligand, and forms (6,3) plane nets by means of intermolecular electrostatic interactions between N-oxide moieties. X-ray powder diffraction studies show that upon desolvation, compound 2 maintains its original ladder framework.     

Synthesis,characterization, cytotoxicity,and molecular docking studies of ampyrone-based transition metal complexes

Transition Metal Chemistry - A novel series of mononuclear transition metal complexes, [Cu(L)Cl] 1, [Zn(L)Cl] 2, [Pd(L)Cl] 3, [Cd(L)I] 4, [Pt(L)Cl] 5, and [Hg(L)Cl] 6, was constructed from a...     

Electrophilic ruthenium(VI) nitrido complex containing Kläui's oxygen tripodal ligand

Treatment of [n-Bu4N][Ru(N)Cl4] with [AgL(OEt)] (L(OEt)- = [(eta5-C5H5)Co{P(O)(OEt)2}3]-) afforded the ruthenium(VI) nitrido complex [L(OEt)Ru(N)Cl2] (1), which reacted with PPh3 to give the ruthenium(IV) phosphiniminato complex [L(OEt)Ru(NPPh3)Cl2] (2). The cyclic voltammogram of 2 displays the RuIV/III couple at ca. 0 V vs ferrocenium/ferrocene. Treatment of 1 with Me3NO afforded [LOEtRu(NO)Cl2] (3), which reacted with Ag(OTf) (OTf- = triflate) to give the chloro-bridged tetranuclear ruthenium/silver complex [L(OEt)Ru(NO)Cl2]2[Ag(OTf)]2 (4). Treatment of 1 with Na2S2O3 gave the thionitrosyl complex [L(OEt)Ru(NS)Cl2] (5). The solid-state structures of 1-4 have been established by X-ray crystallography.     

Macrocycle-supported titanium complexes with chelating imido ligands: analogues of ansa-metallocenes

Reactions of 1,4-dimethyl-1,4,7-triazacyclononane (L1a) and 1,4-diisopropyl-1,4,7-triazacyclononane (L1b) to form 1-aminopropyl-4,7-di-R-1,4,7-triazacyclononane [R = Me (H2L3a) or Pri (H2L3b)] and 1-(2-aminobenzyl)-4,7-di-R-1,4,7-triazacyclononane [R = Me (H2L5a) or Pri (H2L5b)] are reported. Reaction of H2L3a and H2L5a with [Ti(NMe2)2Cl2] gives the ansa-linked macrocycle-imido complexes [Ti(kappa 4-L3a)Cl2] (5a) and [Ti(kappa 4-L5a)Cl2] (6a), respectively, and NHMe2. Reaction of H2L3a with [Ti(NBut)Cl2(py)3] gives [Ti(NBut)(kappa 3-H2L3a)Cl2] (7), which possesses a pendant alkylamine group that does not undergo amine/tert-butylimido group exchange to give 5a and ButNH2. However, reaction of H2L3b and H2L5b with [Ti(NBut)Cl2(py)3] does give amine/tert-butylimido group exchange to form [Ti(kappa 4-L3b)Cl2] (5b), [Ti(kappa 4-L5b)Cl2] (8b), and ButNH2. The compounds 5a,b and 6a,b are isolobal analogues of group 4 ansa-metallocene complexes and relatives of titanium cyclopentadienyl-amido constrained geometry olefin polymerization catalysts. Reaction of 5b with AgOTf affords [Ti(kappa 4-L3b)(OTf)Cl] (8) as the major product, the crystal structure of which has been determined. Alkylation of 6b by RLi gives the dialkyl derivatives [Ti(kappa 4-L5b)(R)2] [R = Me (9) or CH2SiMe3 (10)]. The ethylene polymerization capability of the compounds 5a,b, 6a,b, and 10 in the presence of methylaluminoxane has been determined and compared to that of [Ti(NBut)(kappa 3-L1a,b)Cl2] (11a,b); in all instances, low yields of high-molecular-weight polymer are obtained.     

Synthesis and structural characterization of lanthanide picrate complexes with a new binaphthylamide

Solid complexes of lanthanide picrates with N-Ethyl-2-{2′-[(ethyl-phenyl-carbamoyl)-methoxy]-[1,1′]binaphthalenyl-2-yloxy}-N-phenyl-acetamide (L), [Ln(pic)₃L] (Ln=La, Tb, Y), have been prepared and characterized by elemental analysis, IR and ¹H NMR spectra. The molecular structure of [Tb(pic)₃L] shows that the Tb(III) ion is nine-coordinated by four oxygen atoms from the L and five from two bidentate and one unidentate picrates. The complex forms a 1D supramolecular structure along z-axis.     

Synthesis, chemistry and structures of complexes of the dioxovanadium(V) halides VO2F and VO2Cl

[VO2F(L-L)] (L-L = 2,2'-bipyridyl, 1,10-phenanthroline, Me2N(CH2)2NMe2) and [VO2F(py)2] (py = pyridine) have been prepared from the corresponding [VOF3(L-L)] or [VOF3(py)2] and O(SiMe3)2 in MeCN solution. VO2F (itself made from VOF3 and O(SiMe3)2 in MeCN) forms [Me4N][VO2F2] with [Me4N]F, but does not react with neutral N- or O-donor ligands. VO2Cl, prepared from VOCl3 and ozone, reacts with 2,2'-bipyridyl or 1,10-phenanthroline to form [VO2Cl(L-L)], with pyridine or pyridine-N-oxide (L) to produce [VO2Cl(L)2], and with OPPh3 or OAsPh3 (L') gives [VO2Cl(L')]. A second product from the OPPh3 system is the ionic [VO2(OPPh3)3][VO2Cl2] containing a trigonal bipyramidal cation. Neither VO2F nor VO2Cl form isolable complexes with MeCN, thf or MeO(CH2)2OMe, and both are reduced by P-, As-, S- or Se-donor ligands. [Ph4As][VO2X2] (X = F or Cl) react with 2,2'-bipyridyl to form [VO2X(2,2'-bipyridyl)], but similar reactions with weaker O-donor ligands fail. The complexes have been characterised by IR, multinuclear NMR (1H, 19F, 51V or 31P) and UV-visible spectroscopy. X-ray crystal structures are reported for [VO2F(py)2], [VO2Cl(L)2] (L = py or pyNO) and [VO2(OPPh3)3][VO2Cl2].     

Highly luminescent, visible-emitting lanthanide macrocyclic chelates stable in water and derived from the cyclen framework

Two new tetraazamacrocyclic ligands are designed with the aim of sensitizing the luminescence of Tb(III) and Eu(III) ions in water: L5 [1,4,7,10-tetrakis[N-(phenacyl)carbamoylmethyl]-1,4,7,10-tetraazacyclododecane] and L6 [1,4,7,10-tetrakis[N-(4-phenylphenacyl)carbamoylmethyl]-1,4,7,10-tetraazacyclododecane]. These ligands react with lanthanide trifluoromethanesulfonates to yield stable 1:1 complexes in water (log K = 12.89 +/- 0.15 for EuL5). X-ray diffraction on [Tb(L5)(H(2)O)](CF(3)SO(3))(3) (P1 macro, a = 13.308(3) A, b = 14.338(3) A, c = 16.130(3) A, alpha = 101.37(3) degrees, beta = 96.16(3) degrees, gamma = 98.60(3) degrees ) shows the Tb(III) ion lying on a C(4) axis and being 9-coordinate, with one water molecule bound in its inner coordination sphere. The absolute quantum yields are determined in aerated water for the complexes formed with ions used in fluoroimmunoassays (Ln = Sm, Eu, Tb, and Dy). Large values are found for [Tb(H(2)O)(L5)](3+) and [Eu(H(2)O)(L6)](3+), in line with the molecular design of the receptors: 23.1% and 24.7%, respectively. The intense luminescence of these ions results from efficient intersystem crossing and L --> Ln energy transfer processes, as well as from a suitable shielding of the emitting ions from radiationless deactivation.     

Anion recognition of chloride and bromide by a rigid dicobalt(II) cryptate

The crystal structures of [Co 2L(Cl)](ClO 4) 3 ( 1), [Co 2L(Br)](ClO 4) 3 ( 2), [Co 2L(OH)(OH 2)]I 3 ( 3), and [Co 2L (1)(Cl)](ClO 4) 3 ( 4), the density functional theory calculations, as well as the binding constants of [Co 2L] (4+) toward Cl (-) and Br (-) and of [Co 2L (1)] (4+) toward Cl (-), are reported in this paper (L = N[(CH 2) 2NHCH 2(C 6H 4- p)CH 2NH(CH 2) 2] 3N, L (1) = N[(CH 2) 2NHCH 2(C 6H 4- m)CH 2NH(CH 2) 2] 3N). The rigid dicobalt(II) cryptate [Co 2L] (4+) shows the recognition of Cl (-) and Br (-) but not of F (-) and I (-), because of the size matching to its rigid cavity. We also found that the relative rigid tripodal skeleton of L than that of L (1) results in the higher affinity of [Co 2L] (4+) toward Cl (-). Magnetic susceptibility measurements of 1 and 2 indicate that the two Co(II) atoms in the cryptates are antiferromagnetically coupled through the Cl (-)/Br (-) bridge, with g = 2.19, J = -13.7 cm (-1) for 1, and g = 2.22, J = -17.1 cm (-1) for 2.     

Luminescent complexes of Re(I) and Ru(II) with appended macrocycle groups derived from 5,6-dihydroxyphenanthroline: cation and anion binding

A range of ligands in which a macrocyclic unit is fused to a 1,10-phenanthroline unit has been prepared starting from 5,6-dihydroxyphenanthroline. The ligands are L1 in which the pendant ligand is 18-crown-6; L2, in which the pendant ligand is benzo-24-crown-8; and L(3), in which the macrocycle contains two carboxamide units. Ligands L1 and L2 can bind Group 1 and 2 metal cations in their crown-ether cavities; L3 contains two H-bond (amide) donors and is suitable for anion-binding. Luminescent complexes of the form [Ru(bipy)2L]2+, [ReL(CO)3Cl] and [RuL(CN)4]2- were prepared and some were structurally characterised; their interactions with various guest species were investigated by luminescence and NMR spectroscopy. For complexes with the crown ethers (L1 and L2), binding of K+ was rather weak, but the electrostatic effect due to the charge on the host complex was clear with [RuL1(CN)4]2- binding K+ more strongly than [Ru(bipy)2L1]2+. Binding to the pendant crown ethers was much stronger with Ba2+, and both [ReL1(CO)3Cl] and [ReL2(CO)3Cl] showed substantial luminescence quenching in MeCN on addition of Ba2+ ions, with binding constants of 4.5 x 10(4) M(-1) for [ReL1(CO)3Cl]/Ba2+ and 1.3 x 10(5) M(-1) for [ReL2(CO)3Cl]/Ba2+. Complexes [Ru(bipy)2L3]2+ and [ReL3(CO)3Cl], due to their H-bond donor sites, showed binding of dihydrogenphosphate to the macrocycle. Whereas [ReL3(CO)3Cl] showed 1 : 1 binding with (H2PO4)- in dmso with a binding constant of 65 M(-1), [Ru(bipy)2L3]2+ showed 1 : 2 binding, with microscopic association constants of ca. 1 x 10(6) and 1.6 x 10(6) M(-1) in MeCN. The fact that K2 > K1 suggests a cooperative interaction whereby binding of the first anion makes binding of the second one easier to an extent which overcomes electrostatic effects, and a model for this is proposed which also accounts for the substantial increase in luminescence from [Ru(bipy)2L3]2+ (5-fold enhancement) when the second (H2PO4)- anion binds. Both [Ru(bipy)2L3]2+ and [ReL3(CO)3Cl] undergo complete luminescence quenching and a change in colour to near-black in the presence of (anhydrous) fluoride in MeCN, probably due to deprotonation of the carboxamide group. These changes are however irreversible on a long timescale and lead to slow decomposition.     

五氯亚硝酰合铱酸根[Ir(NO)Cl5][-]在盐酸-磷酸三丁酯体系中的萃取行为

铱在萃取过程中的行为与其存在状态有关.王水溶解含铱物料有[Ir(NO)Cl_5]~-生成,亚硝酸盐配位法分离贵金属时,盐酸酸化可使[Ir(NO_2)_6]~(3-)转变为[Ir(NO)Cl_5]~-。[Jr(NO)Cl_5]~-在溶液中的变化极其复杂,它在冶金过程中必然影响到有关的分离.本文研究[Ir(NO)Cl_5]~-在盐酸-磷酸三丁酯(TBP)体系中的萃取行为,寻求最佳萃取条件.     

Tris(1,5-dimethyl-1H-pyrazol-4-yl)-4,4,4-trifluorobutane-1,3-dionato)(dimethanol)terbium(III): synthesis,crystal structure,and luminescent properties

Russian Journal of Coordination Chemistry - The neutral complex [Tb(L3)(MeOH)2] was unexpectedly formed as the major product of the reaction of Tb(NO3)3 ? 6H2O with...     

From a monomer to a protein-sized, doughnut-shaped coordination oligomer-the influence of side chains of C3-symmetric ligands in supramolecular chemistry

Herein we describe the importance of side chains in C3-symmetric ligands in supramolecular chemistry. The reaction of the new ligand tris(5-bromo-2-methoxybenzylidene)triaminoguanidinium chloride [H3Me3Br3L]Cl (1) with ZnCl2 results in the formation of the monomeric complex (Et3NH)2[(ZnCl2)3Me3Br3L] (2), in which the ligand remains in a conformation less favourable for the coordination of metal centres. The use of the related tris(5-bromo-2-hydroxybenzylidene)triaminoguanidinium chloride, [H6Br3L]Cl, under similar conditions, results in the formation of two different dimeric compounds (NH4)[{[Zn(NH3)]3Br3L}2{mu-(OH)}3]1/4MeOH (3) and [Zn{Zn2(OH2)3(NH3)Br3L}2] (4), depending on the solvent mixture used. The comparable reaction of the ligand tris(5-bromo-2-hydroxy-3-methoxybenzylidene)triaminoguanidinium chloride [H6(OMe)3Br3L]Cl (5), leads to the formation of a doughnut-shaped, protein-sized coordination oligomer (Et3NH)18[{Zn[Zn2Cl{(OMe)3Br3L}]2}6(mu-Cl)6(OH2)6]x CH3CN (6), which comprises six dimeric [Zn5{(OMe)3Br3L}2] units. Whereas 3 and 4 decompose in DMSO solution, 6 is surprisingly stable in the same solvent.     

Synthesis, spectral and electrochemical properties of Al(III) and Zn(II) complexes with flavonoids

The synthesis, electrochemical and spectral (UV-vis, 1H NMR, IR, fluorescence) properties as well as thermal behaviors of Al(III) and Zn(II) complexes with the flavonoids quercetin (H2L(1)), rutin (H2L(2)) and galangin (HL(3)) are presented. The complexes may be formulated as [Al2(L(1))(H2O)8]Cl4, [Al3(L(2))2(H2O)12]Cl5, [Al(L(3))(H2O)4]Cl2, [Zn2(L(1))(H2O)4]Cl2, [Zn3(L(2))2(H2O)6]Cl2 and [Zn(L(3))(H2O)2]Cl. The higher fluorescence intensities of the complexes related to the free flavonoids, are attributed to the coordination of the ligands to the small, highly charged Al(III) and Zn(II) ions. The coordination effectively increases the rigidity of the ligand structure and increases the fluorescence quantum yield by reducing the probability of non-radiative energy dissipation process. Antioxidant activities of the compounds were also investigated under an electrochemical point of view. The cyclic voltammetric data show a considerable decrease of the oxidation potentials of the complexes related to that of the free flavonoids. Thus, the flavonoid-metal complexes are more effective antioxidants than the free flavonoids.     

Formation and reactivity of the Os(IV)-azidoimido complex, PPN[Os(IV)(bpy)(Cl)(3)(N(4))

Reactions between the Os(VI)-nitrido complexes, [OsVI(L2)(Cl)3(N)] (L2 = 2,2'-bipyridine (bpy) ([1]), 4,4'-dimethyl-2,2'-bipyridine (Me2bpy), 1,10-phenanthroline (phen), and 4,7-diphenyl-1,10-phenanthroline (Ph2phen)), and bis-(triphenylphosphoranylidene)ammonium azide (PPNN3) in dry CH3CN at 60 degrees C under N2 give the corresponding Os(IV)-azidoimido complexes, [OsIV(L2)(Cl)3(NN3)]- (L2 = bpy = [2]-, L2 = Me2bpy = [3]-, L2 = phen = [4]-, and L2 = Ph2phen = [5]-) as their PPN+ salts. The formulation of the N42- ligand has been substantiated by 15N-labeling, IR, and 15N NMR measurements. Hydroxylation of [2]- at Nalpha with O<--NMe3.3H2O occurs to give the Os(IV)-azidohydroxoamido complex, [OsIV(bpy)(Cl)3(N(OH)N3)] ([6]), which, when deprotonated, undergoes dinitrogen elimination to give the Os(II)-dinitrogen oxide complex, [OsII(bpy)(Cl)3(N2O)]- ([7]-). They are the first well-characterized examples of each kind of complex for Os.     

Gold complexes with potentially tri- and tetradentate phosphinothiolate ligands

Reactions of [Au(PPh3)Cl], (Bu4N)[AuCl4] and the organometallic gold complex [Au(damp-C1,N)Cl2] (damp- = 2-(N,N-dimethylaminomethyl)phenyl) with the potentially tri- and tetradentate proligands PhP(C6H3-SH-2-R-3)2 (H2L1a, R = SiMe3; H2L1b, R = H) and P(C6H4-SH-2)3 (H3L2) result in the formation of mono- or dinuclear gold complexes depending on the precursor used. Monomeric complexes of the type [AuL1Cl] are formed upon the reaction with [Au(damp-C1,N)Cl2], but small amounts of dinuclear [AuL1]2 complexes with gold in two different oxidation states, +1 and +3, have been isolated as side-products. The dinuclear compounds are obtained in better yields from [AuCl4]-. A dinuclear complex having two Au(III) centers can be isolated from the reaction of [Au(PPh3)Cl] with H3L2, whereas from the reaction with H2L1b the mononuclear [Au(Ph3P)HL1b] is obtained, which contains a three-coordinate gold atom. Comparatively short gold-gold distances have been found in the dinuclear complexes (2.978(2) and 3.434(1) A). They are indicative of weak gold-gold interactions, which is unusual for gold(III).