Synthesis of Pd complexes combined with photosensitizing of a ruthenium(II) polypyridyl moiety through a series of substituted bipyrimidine bridges. Substituent effect of the bridging ligand on the photocatalytic dimerization of alpha-methylstyrene

Mononuclear ruthenium complexes and dinuclear Ru...Pd complexes having a series of 2,2'-bipyrimidine ligands, [(bpy)2Ru(Ln)]2+ [Ln = 2,2'-bipyrimidine (L1), 5,5'-dimethyl-2,2'-bipyrimidine (L2), 5,5'-dibromo-2,2'-bipyrimidine (L3), 4,4'-dimethyl-2,2'-bipyrimidine (L4), and 4,4',6,6'-tetramethyl- 2,2'-bipyrimidine (L5)] and [(bpy)2Ru(Ln)PdL]m+ [Ln = L1-L3; PdL = PdMeCl (m = 2) and PdMe(solvent) (m = 3)], are prepared, and the obtained complexes are characterized by means of spectroscopic and crystallographic methods. Introduction of the substituents on the bipyrimidine ligands led to the substantial differences in their electrochemical and photophysical properties. Density functional theory calculations have been performed to understand the substituent effect on the ground-state molecular orbital energy level. Reactivity studies on the catalytic dimerization of alpha-methylstyrene revealed that the Pd complex having a Br-substituted bipyrimidine ligand were much more active than those of the corresponding Pd complexes having methyl-substituted or nonsubstituted bipyrimidine ligands.     

Diverse lanthanide coordination polymers tuned by the flexibility of ligands and the lanthanide contraction effect: syntheses, structures and luminescence

Two new flexible exo-bidentate ligands were designed and synthesized, incorporating different backbone chain lengths bearing two salicylamide arms, namely 2,2'-(2,2'-oxybis(ethane-2,1-diyl)bis(oxy))bis(N-benzylbenzamide) (L(I)) and 2,2'-(2,2'-(ethane-1,2-diylbis(oxy))bis(ethane-2,1-diyl))bis(oxy)bis(N-benzylbenzamide) (L(II)). These two structurally related ligands are used as building blocks for constructing diverse lanthanide polymers with luminescent properties. Among two series of lanthanide nitrate complexes which have been characterized by elemental analysis, TGA analysis, X-ray powder diffraction, and IR spectroscopy, ten new coordination polymers have been determined using X-ray diffraction analysis. All the coordination polymers exhibit the same metal-to-ligand molar ratio of 2?:?3. L(I), as a bridging ligand, reacts with lanthanide nitrates forming two different types of 2D coordination complexes: herringbone framework {[Ln(2)(NO(3))(6)(L(I))(3)·mC(4)H(8)O(2)](∞) (Ln = La (1), and Pr (2), m = 1, 2)} as type I,; and honeycomb framework {[Ln(2)(NO(3))(6)(L(I))(3)·nCH(3)OH](∞) (Ln = Nd (3), Eu (4), Tb (5), and Er (6), n = 0 or 3)} as type II, which change according to the decrease in radius of the lanthanide. For L(II), two distinct structure types of 1D ladder-like coordination complexes were formed with decreasing lanthanide radii: [Ln(2)(NO(3))(6)(L(II))(3)·2C(4)H(8)O(2)](∞) (Ln = La (7), Pr (8), Nd (9)) as type III, [Ln(2)(NO(3))(6)(L(I))(3)·mC(4)H(8)O(2)·nCH(3)OH](∞) (Ln = Eu (10), Tb (11), and Er (12), m, n = 2 or 0) as type IV. The progressive structural variation from the 2D supramolecular framework to 1D ladder-like frameworks is attributed to the varying chain length of the backbone group in the flexible ligands. The photophysical properties of trivalent Sm, Eu, Tb, and Dy complexes at room temperature were also investigated in detail.     

含轴手性磺酸配体的镉配合物(英)

The crystal structure of [Cd(BDA)(phen)₂(H₂O)](H₂O)₂ (1) (BDA=6,6′-dibromo-2,2′-dimethoxy-1,1′-binaphthylene-4,4′-disulfonate, phen=1,10-phenanthroline)consists of a cadmium center whose coordination environment can be best described as a slightly distorted octahedron defined four nitrogen atoms from two phen ligands and two oxygen atoms differently from BDA ligand and water. There are strong hydrogen-bonding interactions between water and sulfonate group of BDA ligands to construct the 3D network. CCDC: 277921.     

Complexes formed between the quadridentate, heterocyclic molecules 6,6'-bis-(5,6-dialkyl-1,2,4-triazin-3-yl)-2,2'-bipyridine (BTBP) and lanthanides(III): implications for the partitioning of actinides(III) and lanthanides(III)

New hydrophobic, tetradentate nitrogen heterocyclic reagents, 6,6'-bis-(5,6-dialkyl-1,2,4-triazin-3-yl)-2,2'-bipyridines (BTBPs) have been synthesised. These reagents form complexes with lanthanides and crystal structures with 11 different lanthanides have been determined. The majority of the structures show the lanthanide to be 10-coordinate with stoichiometry [Ln(BTBP)(NO3)3] although Yb and Lu are 9-coordinate in complexes with stoichiometry [Ln(BTBP)(NO3)2(H2O)](NO3). In these complexes the BTBP ligands are tetradentate and planar with donor nitrogens mutually cisi.e. in the cis, cis, cis conformation. Crystal structures of two free molecules, namely C2-BTBP and CyMe4-BTBP have also been determined and show different conformations described as cis, trans, cis and trans, trans, trans respectively. A NMR titration between lanthanum nitrate and C5-BTBP showed that two different complexes are to be found in solution, namely [La(C5-BTBP)2]3+ and [La(C5-BTBP)(NO3)3]. The BTBPs dissolved in octanol were able to extract Am(III) and Eu(III) from 1 M nitric acid with large separation factors.     

Spontaneous formation of novel luminescent dinuclear lanthanide complexes that emit in the visible and near-IR regions

The reaction of tetrasodium-4,4',6,6'-tetracarboxy-2,2'-bipyridine (Na(4)L) with various lanthanide ions yields a family of isostructural supramolecular {Na(2)[Ln(2)L(2)]} complexes (1-4), where Ln(III) = Eu, Nd, Gd, and Tb. Strikingly, these complexes luminesce in buffered H(2)O or D(2)O solutions in either the visible or near-IR regions, despite their high hydration states.     

Syntheses, structures, luminescence, and magnetic properties of one-dimensional lanthanide coordination polymers with a rigid 2,2'-bipyridine-3,3',6,6'-tetracarboxylic acid ligand

A series of novel one-dimensional (1-D) lanthanide coordination polymers (CPs), with the general formula {[Ln(bptcH)(H(2)O)(2)]·H(2)O}(n) (Ln = Nd(III) (1), Eu(III) (2), Gd(III) (3), Tb(III) (4), Dy(III) (5), Ho(III) (6), or Er(III) (7)) have been synthesized by the solvothermal reactions of the corresponding lanthanide(III) picrates and 2,2'-bipyridine-3,3',6,6'-tetracarboxylic acid (bptcH(4)). These polymers have been structurally characterized by single-crystal X-ray diffraction, IR, PXRD, thermogravimetric (TGA), and elemental analysis. Coordination polymers 1-7 are isostructural; they possess the same 3D supramolecular architectures and crystallize in triclinic space group P1?. The frameworks constructed from dinuclear lanthanide building blocks exhibit one-dimensional double-stranded looplike chain architectures, in which the bptcH(3-) ions adopted hexadentate coordination modes. The Eu(III) (2) and Tb(III) (4) polymers exhibit characteristic photoluminescence in the visible region. The magnetic properties of polymers 2, 3, and 5 have been investigated through the measurement of their magnetic susceptibilities over the temperature range of 1.8-300 K.     

Syntheses, structures, and luminescence of novel lanthanide complexes of tripyridylamine, N,N,N',N'-tetra(2-pyridyl)-1,4-phenylenediamine and N,N,N',N'-tetra(2-pyridyl)biphenyl-4,4'-diamine

Two novel blue luminescent bridging ligands N,N,N',N'-tetra(2-pyridyl)-1,4-phenylenediamine (tppd) and N,N,N',N'-tetra(2-pyridyl)-1,1-biphenyl-4,4'-diamine (tpbpd) have been synthesized. Several novel lanthanide complexes containing 2,2',2"-tripyridylamine (2,2',2"-tpa), 2,2',3"-tpa, tppd, or tpbpd ligands have been synthesized and characterized structurally, which include Pr(hfa)3(2,2',2"-tpa), I, Ln(tmhd)3(2,2',3"-tpa), 2 (Ln = Dy, 2a; Eu, 2b; Tb, 2c; Sm, 2d), [Eu(tmhd)3][Pr(hfa)3](2,2',3"-tpa), 3, [Pr(hfa)3]2(tppd), 4, and [Ln(hfa)3]2(tpbpd), 5, where Ln = Pr (5a), Eu (5b), tmhd = 2,2,6,6-tetramethyl-3,5-heptanedionato, and hfa = hexafluoroacetylacetonate. The Dy(III), Eu(III), and Tb(III) complexes display a bright photoluminescence, which can be achieved by either a direct excitation process or an indirect excitation process. Compounds 2a-2d can be sublimed readily.     

Novel lanthanide(II) complexes supported by carbon-bridged biphenolate ligands: synthesis, structure and catalytic activity

[Ln[N(SiMe3)2]2(THF)2](Ln = Sm, Yb) reacts with 1 equiv. of carbon-bridged biphenols, 2,2'-methylene-bis(6-tert-butyl-4-methylphenol)(L1H2) or 2,2'-ethylidene-bis(4,6-di-tert-butylphenol)(L2H2), in toluene to give the novel aryloxide lanthanide(II) complexes [[LnL1(THF)n]2](Ln = Sm, n = 3 (1); Ln = Yb, n = 2 (2)) and [[LnL2(THF)3]2](Ln = Sm (5); Ln = Yb (6)) in quantitative yield, respectively. Addition of 2 equiv. of hexamethylphosphoric triamide (HMPA) to a tetrahydrofuran (THF) solution of 1, 2 and 5 affords the corresponding HMPA-coordinated complexes, [[LnL1(THF)m(HMPA)n]2(THF)y](Ln = Sm, n = 2, m = 0, y = 2 (3); Ln = Yb, m = 1, n = 1, y = 6 (4)) and [[SmL2(HMPA)2]2](7) in excellent yields. The single-crystal structural analyses of 3, 4 and 7 revealed that these aryloxide lanthanide(II) complexes are dimeric with two Ln-O bridges. The coordination geometry of each lanthanide metal can be best described as a distorted trigonal bipyramid. Complexes 1-3, 5 and 7 can catalyze the ring-opening polymerization of epsilon-caprolactone (epsilon-CL), and 1-3, along with 5 show moderate activity for the ring-opening polymerization of 2,2-dimethyltrimethylene carbonate (DTC) and the copolymerization of epsilon-CL and DTC to give random copolymers with high molecular weights and relatively narrow molecular weight distributions..     

Hierarchical assembly of homochiral porous solids using coordination and hydrogen bonds

A family of homochiral metal carboxylate coordination polymers have been synthesized by treating 2,2'-dihydroxy-1,1'-binaphthalene-6,6'-dicarboxylic acid (H(2)BDA) with metal salts at elevated temperatures. BDA ligands link adjacent metal centers to form 1D coordination polymeric chains using the carboxylate functionality, while the hydroxyl groups of BDA ligands form H-bonds with carboxylate oxygen atoms to link 1D coordination polymeric chains into open frameworks of higher dimensionality. We also present evidence for the important role played by H-bonds in the stabilization of open framework structures which allows for the hierarchical assembly of chiral porous solids.     

有机二磺酸锰配合物(英)

The crystal structure of [Mn(BDA)(bpy)₂(H₂O)](H₂O)₂ (1)(BDA=6,6′-dibromo-2,2′-dimethoxy-1,1′-binaphthylene-4,4′-disulfonate, bpy=2,2′-bipyridine) composes of a manganese center which is surrounded by two nitrogen atoms from 2,2′-bipyridine and four oxygen atoms from three water and sulfonate group of BDA that also participate in H-bonding interactions to form 3D network as well as some uncoordinated water. CCDC: 277922.     

Highly luminescent bis-diketone lanthanide complexes with triple-stranded dinuclear structure

A new bis-β-diketone, 3,3'-bis(4,4,4-trifluoro-1,3-dioxobutyl)biphenyl (BTB), has been designed and prepared for the synthesis of a series of dinuclear lanthanide complexes [Ln(2)(BTB)(3)(C(2)H(5)OH)(2)(H(2)O)(2)] [Ln = Eu (1), Gd (2)], [Ln(2)(BTB)(3)(DME)(2)] [Ln = Nd (3), Yb (4); DME = ethylene glycol dimethyl ether] and [Eu(2)(BTB)(3)(L)(2)] [L = 2,2-bipydine (5); 1,10-phenanthroline (6); 4,7-diphenyl-1,10-phenanthroline (7)]. Complexes 1-7 have been characterized by various spectroscopic techniques and their photophysical properties are investigated. X-ray crystallographical analysis reveals that complexes 1, 3 and 4 adopt triple-stranded dinuclear structures which are formed by three bis-bidentate ligands with two lanthanide ions. The complexes 1 and 3-7 display strong visible red or NIR luminescence upon irradiation at ligand band around 372 nm, depending on the choice of the lanthanide. The solid-state photoluminescence quantum yields and the lifetimes of Eu(3+) complexes are determined and described.     

C2-symmetric bis(oxazolinato)lanthanide catalysts for enantioselective intramolecular hydroamination/cyclization

C(2)-symmetric bis(oxazolinato)lanthanide complexes of the type [(4R,5S)-Ph(2)Box]La[N(TMS)(2)](2), [(4S,5R)-Ar(2)Box]La[N(TMS)(2)](2), and [(4S)-Ph-5,5-Me(2)Box]La[N(TMS)(2)](2) (Box = 2,2'-bis(2-oxazoline)methylenyl; Ar = 4-tert-butylphenyl, 1-naphthyl; TMS = SiMe(3)) serve as precatalysts for the efficient enantioselective intramolecular hydroamination/cyclization of aminoalkenes and aminodienes. These new catalyst systems are conveniently generated in situ from the known metal precursors Ln[N(TMS)(2)](3) or Ln[CH(TMS)(2)](3) (Ln = La, Nd, Sm, Y, Lu) and 1.2 equiv of commercially available or readily prepared bis(oxazoline) ligands such as (4R,5S)-Ph(2)BoxH, (4S,5R)-Ar(2)BoxH, and (4S)-Ph-5,5-Me(2)BoxH. The X-ray crystal structure of [(4S)-(t)BuBox]Lu[CH(TMS)(2)](2) provides insight into the structure of the in situ generated precatalyst species. Lanthanides having the largest ionic radii exhibit the highest turnover frequencies as well as enantioselectivities. Reaction rates maximize near 1:1 BoxH:Ln ratio (ligand acceleration); however, increasing the ratio to 2:1 BoxH:Ln decreases the reaction rate, while affording enantiomeric excesses similar to the 1:1 BoxH:Ln case. A screening study of bis(oxazoline) ligands reveals that aryl stereodirecting groups at the oxazoline ring 4 position and additional substitution (geminal dimethyl or aryl) at the 5 position are crucial for high turnover frequencies and good enantioselectivities. The optimized precatalyst, in situ generated [(4R,5S)-Ph(2)Box]La[N(TMS)(2)](2), exhibits good rates and enantioselectivities, comparable to or greater than those achieved with chiral C(1)-symmetric organolanthanocene catalysts, even for poorly responsive substrates (up to 67% ee at 23 degrees C). Kinetic studies reveal that hydroamination rates are zero order in [amine substrate] and first order in [catalyst], implicating the same general mechanism for organolanthanide-catalyzed hydroamination/cyclizations (intramolecular turnover-limiting olefin insertion followed by the rapid protonolysis of an Ln-C bond by amine substrate) and implying that the active catalytic species is monomeric.     

Synthesis and luminescent properties of novel lanthanide(III) beta-diketone complexes with nitrogen p,p'-disubstituted aromatic ligands

Tris-beta-diketonate lanthanide(III) complexes (Ln = Eu, Er, Yb, Tb), of general formula [Ln(acac)3 L(m)], with chelating ligands such as 4,7-disubstituted-1,10-phenanthrolines and 4,4'-disubstituted-2,2'-bipyridines, have been synthesized and fully characterized. The inductive effects of the para-substituents on the aromatic N-donor ligands have been investigated both in the solid and in the solution states. Single-crystal X-ray structures have been determined for the diethyl 1,10-phenanthroline-4,7-dicarboxylate europium and 4,4'-dimethoxy-2,2'-bipyridine erbium derivatives, revealing a distorted square antiprismatic geometry around the lanthanide atom in both cases. The influence exerted by the p,p'-substituents with respect to the nitrogen coordinating atoms on the Ln-N bond distances is discussed comparing the geometrical parameters with those found for the crystal structures containing the fragments [Ln(III)(phen)] and [Ln(III)(bipy)] obtained from the Cambridge Structural Database. The influence exerted by the electron-attracting groups on the coordination ability of the ligands, that in some cases becomes lack of coordination of the lanthanide ions, has been also detected in solution where the loss of the ligand has been followed by UV-vis spectroscopy. Moreover, the use of relatively long alkoxy chains as substituents on the 1,10-phenanthroline ligand led to the formation of a promesogenic lanthanide complex, whose thermal behavior is encouraging for the synthesis of new lanthanide liquid-crystalline species.     

Synthesis and catalytic activity of group 5 metal amides with chiral biaryldiamine-based ligands

A new series of group 5 metal amides have been prepared from the reaction between V(NMe(2))(4) or M(NMe(2))(5) (M = Nb, Ta) and chiral ligands, (R)-2,2'-bis(mesitoylamino)-1,1'-binaphthyl (1H(2)), (R)-5,5',6,6',7,7',8,8'-octahydro-2,2'-bis(mesitoylamino)-1,1'-binaphthyl (2H(2)), (R)-6,6'-dimethyl-2,2'-bis(mesitoylamino)-1,1'-biphenyl (3H(2)), (R)-2,2'-bis(mesitylenesulfonylamino)-6,6'-dimethyl-1,1'-biphenyl (4H(2)), (R)-2,2'-bis(diphenylthiophosphoramino)-1,1'-binaphthyl (5H(2)), (R)-2,2'-bis[(3-tert-butyl-2-hydroxybenzylidene)amino]-6,6'-dimethyl-1,1'-biphenyl (6H(2)), (R)-2,2'-bis[(3,5-di-tert-butyl-2-hydroxybenzylidene)amino]-6,6'-dimethyl-1,1'-biphenyl (7H(2)), (R)-2,2'-bis[(3-tert-butyl-2-hydroxybenzylidene)amino]-1,1'-binaphthyl (8H(2)), (S)-2-(mesitoylamino)-2'-(dimethylamino)-1,1'-binaphthyl (9H), and (R)-2-(mesitoylamino)-2'-(dimethylamino)-6,6'-dimethyl-1,1'-biphenyl (10H), which are derived from (R) or (S)-2,2'-diamino-1,1'-binaphthyl, and (R)-2,2'-diamino-6,6'-dimethyl-1,1'-biphenyl, respectively. Treatment of V(NMe(2))(4) or M(NMe(2))(5) (M = Nb, Ta) with 1 equiv of C(2)-symmetric amidate ligands 1H(2), 2H(2), 3H(2), 4H(2), and 5H(2), or Schiff base ligands 6H(2), 7H(2) and 8H(2) at room temperature gives, after recrystallization from a benzene, toluene or n-hexane solution, the vanadium amides (1)V(NMe(2))(2) (11), (2)V(NMe(2))(2) (14), (3)V(NMe(2))(2) (17), (5)V(NMe(2))(2) (22), (6)V(NMe(2))(2) (23) and (7)V(NMe(2))(2) (24), and niobium amides (1)Nb(NMe(2))(3) (12), (2)Nb(NMe(2))(3) (15), (3)Nb(NMe(2))(3) (18), (4)Nb(NMe(2))(3) (20) and [2-(3-Me(3)C-2-O-C(6)H(3)CHN)-2'-(N)-C(20)H(12)][2-(Me(2)N)(2)CH-6-CMe(3)-C(6)H(3)O]NbNMe(2)·C(7)H(8) (25·C(7)H(8)), and tantalum amides (1)Ta(NMe(2))(3) (13), (2)Ta(NMe(2))(3) (16), (3)Ta(NMe(2))(3) (19) and (4)Ta(NMe(2))(3) (21) respectively, in good yields. Reaction of V(NMe(2))(4) or M(NMe(2))(5) (M = Nb, Ta) with 2 equiv of C(1)-symmetric amidate ligands 9H or 10H at room temperature gives, after recrystallization from a toluene or n-hexane solution, the chiral bis-ligated vanadium amides (9)(2)V(NMe(2))(2)·3C(7)H(8) (27·3C(7)H(8)) and (10)V(NMe(2))(2) (28), and chiral bis-ligated metallaaziridine complexes (10)(2)M(NMe(2))(η(2)-CH(2)NMe) (M = Nb (29), Ta (30)) respectively, in good yields. The niobium and tantalum amidate complexes are stable in a toluene solution at or below 160 °C, while the vanadium amidate complexes degrade via diemthylamino group elimination at this temperature. For example, heating the complex (2)V(NMe(2))(2) (14) in toluene at 160 °C for four days leads to the isolation of the complex [(2)V](2)(μ-NMe(2))(2) (26) in 58% yield. These new complexes have been characterized by various spectroscopic techniques, and elemental analyses. The solid-state structures of complexes 12, 13, and 15-30 have further been confirmed by X-ray diffraction analyses. The vanadium amides are active chiral catalysts for the asymmetric hydroamination/cyclization of aminoalkenes, affording cyclic amines in moderate to good yields with good ee values (up to 80%), and the tantalum amides are outstanding chiral catalysts for the hydroaminoalkylation, giving chiral secondary amines in good yields with excellent ee values (up to 93%).     

Solvothermal syntheses of [Ln(en)3(H2O)x(mu(3-x)-SbS4)] (Ln = La, x = 0; Ln = Nd, x = 1) and [Ln(en)4]SbS4.0.5en (Ln = Eu, Dy, Yb): a systematic study on the formation and crystal structures of new lanthanide thioantimonates(V)

New lanthanide thioantimonate(V) compounds, [Ln(en)3(H2O)x(mu(3-x)-SbS4)] (en = ethylenediamine, Ln = La, x = 0, Ia; Ln = Nd, x = 1, Ib) and [Ln(en)4]SbS4.0.5en (Ln = Eu, IIa; Dy, IIb; Yb, IIc), were synthesized under mild solvothermal conditions by reacting Ln2O3, Sb, and S in en at 140 degrees C. These compounds were classified as two types according to the molecular structures. The crystal structure of type I (Ia and Ib) consists of one-dimensional neutral [Ln(en)3(H2O)x(mu(3-x)-SbS(4))]infinity (x = 0 or 1) chains, in which SbS4(3-) anions act as tridentate or bidentate bridging ligands to interlink [Ln(en)3]3+ ions, while the crystal structure of type II (IIa, IIb, and IIc) contains isolated [Ln(en)4]3+ cations, tetrahedral SbS4(3-) anions, and free en molecules. A systematic investigation of the crystal structures of the five lanthanide compounds, as well as two reported compounds, clarifies the relationship between the molecular structure and the entity of the lanthanide(III) series, such as the stability of the lanthanide(III)-en complexes, the coordination number, and the ionic radii of the metals.     

Polyoxometalate-templated lanthanide-organic hybrid layers based on 6(3)-honeycomb-like 2D nets

The reaction of a double-betaine-containing ligand with LnPMo(12)O(40)·nH(2)O (Ln = Dy, Tb and Er) led to the isolation of new polyoxometalate-templated lanthanide-organic hybrid layers with the molecular formula [Ln(L)(1.5)(H(2)O)(5)][PMo(12)O(40)]·1.5CH(3)CN·2H(2)O (Ln = Dy (1), Tb (2) and Er (3); L = 1,4-bis(pyridinil-4-carboxylato)-l,4-dimethylbenzene). All compounds were characterized by elemental analyses, TG analyses, IR and the single-crystal X-ray diffraction. Compounds 1-3 are isostructural and possess a 2D undulating cationic network [Ln(L)(1.5)(H(2)O)(5)](n)(3n+) with the honeycomb-like cavities. Interestingly, the interval 2D networks are further connected by the H-bonds to form a 3D supramolecular framework. Moreover, two of such identical supramolecular frameworks are 2-fold interpenetrated with each other and encapsulate the α-Keggin-type [PMo(12)O(40)](3-) anionic templates and the solvent molecules. These composite compounds display both luminescent properties (induced by organic ligands and/or lanthanide ions) and electrocatalytic activities towards the reduction of nitrite.     

Luminescence tuning of imidazole-based lanthanide(III) complexes [Ln = Sm, Eu, Gd, Tb, Dy

To tune the lanthanide luminescence in related molecular structures, we synthesized and characterized a series of lanthanide complexes with imidazole-based ligands: two tripodal ligands, tris{[2-{(1-methylimidazol-2-yl)methylidene}amino]ethyl}amine (Me(3)L), and tris{[2-{(imidazol-4-yl)methylidene}amino]ethyl}amine (H(3)L), and the dipodal ligand bis{[2-{(imidazol-4-yl)methylidene}amino]ethyl}amine (H(2)L). The general formulas are [Ln(Me(3)L)(H(2)O)(2)](NO(3))(3)·3H(2)O (Ln = 3+ lanthanide ion: Sm (1), Eu (2), Gd (3), Tb (4), and Dy (5)), [Ln(H(3)L)(NO(3))](NO(3))(2)·MeOH (Ln(3+) = Sm (6), Eu (7), Gd (8), Tb (9), and Dy (10)), and [Ln(H(2)L)(NO(3))(2)(MeOH)](NO(3))·MeOH (Ln(3+) = Sm (11), Eu (12), Gd (13), Tb (14), and Dy (15)). Each lanthanide ion is 9-coordinate in the complexes with the Me(3)L and H(3)L ligands and 10-coordinate in the complexes with the H(2)L ligand, in which counter anion and solvent molecules are also coordinated. The complexes show a screw arrangement of ligands around the lanthanide ions, and their enantiomorphs form racemate crystals. Luminescence studies have been carried out on the solid and solution-state samples. The triplet energy levels of Me(3)L, H(3)L, and H(2)L are 21?000, 22?700, and 23?000 cm(-1), respectively, which were determined from the phosphorescence spectra of their Gd(3+) complexes. The Me(3)L ligand is an effective sensitizer for Sm(3+) and Eu(3+) ions. Efficient luminescence of Sm(3+), Eu(3+), Tb(3+), and Dy(3+) ions was observed in complexes with the H(3)L and H(2)L ligands. Ligand modification by changing imidazole groups alters their triplet energy, and results in different sensitizing ability towards lanthanide ions.     

Lanthanide hydroxide cubane clusters anchoring ferrocenes: model compounds for fixation of organometallic fragments on a lanthanide oxide surface

The reaction of the lanthanide trichloride hexahydrates [LnCl(3).6H(2)O] (Ln = Yb, Lu) with two equivalents of benzoylferrocenoylmethane resulted in the tetranuclear lanthanide hydroxo clusters [Ln(4)(mu(3)-OH)(4)(FcacacPh)(8)] (Ln = Yb (1), Lu (2); FcacacPh = benzoylferrocenoylmethanide). Compounds 1 and 2 are made up of a distorted tetranuclear lanthanide Ln(4)O(4) cubane core consisting of four mu(3)-oxygen atoms while the eight FcacacPh ligands build up the peripheral part of the cluster. These compounds contain the maximum number of ferrocene units anchored to any molecular metal-heteroatom framework reported so far and for which the X-ray structures are known.     

Lanthanide N,N-dimethylaminodiboranates as a new class of highly volatile chemical vapor deposition precursors

New lanthanide N,N-dimethylaminodiboranate (DMADB) complexes of stoichiometry Ln(H(3)BNMe(2)BH(3))(3) and Ln(H(3)BNMe(2)BH(3))(3)(thf) have been prepared, where Ln = yttrium, lanthanum, cerium, praseodymium, neodymium, samarium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, and lutetium, except that isolation of the desolvated complexes proved difficult for Eu and Yb. The tetrahydrofuran (thf) complexes are all monomeric, and most of them adopt 13-coordinate structures in which each DMADB group chelates to the metal center by means of four B-H···Ln bridges (each BH(3) group is κ(2)H; i.e., forms two B-H···Ln interactions). For the smallest three lanthanides, Tm, Yb, and Lu, the metal center is 12 coordinate because one of the DMADB groups chelates to the metal center by means of only three B-H···Ln bridges. The structures of the base-free Ln(H(3)BNMe(2)BH(3))(3) complexes are highly dependent on the size of the lanthanide ions: as the ionic radius decreases, the coordination number decreases from 14 (Pr) to 13 (Sm) to 12 (Dy, Y, Er). The 14-coordinate complexes are polymeric: each metal center is bound to two chelating DMADB ligands and to two "ends" of two ligands that bridge in a Ln(κ(3)H-H(3)BNMe(2)BH(3)-κ(3)H)Ln fashion. In the 13-coordinate complexes, all three DMADB ligands are chelating, but the metal atom is also coordinated to one hydrogen atom from an adjacent molecule. The 12-coordinate complexes adopt a dinuclear structure in which each metal center is bound to two chelating DMADB ligands and to two ends of two ligands that bridge in a Ln(κ(2)H-H(3)BNMe(2)BH(3)-κ(2)H)Ln fashion. The complexes react with water, and the partial hydrolysis product [La(H(3)BNMe(2)BH(3))(2)(OH)](4) adopts a structure in which the lanthanum and oxygen atoms form a distorted cube; each lanthanum atom is connected to three bridging hydroxyl groups and to two chelating DMADB ligands. One B-H bond of each chelating DMADB ligand forms a bridge to an adjacent metal center. Field ionization MS data, melting and decomposition points, thermogravimetric data, and NMR data, including an analysis of the paramagnetic lanthanide induced shifts (LIS), are reported for all of the complexes. The Ln(H(3)BNMe(2)BH(3))(3) compounds, which are highly volatile and sublime at temperatures as low as 65 °C in vacuum, are suitable for use as chemical vapor deposition (CVD) and atomic layer deposition (ALD) precursors to thin films.     

Construction of lanthanide complexes supported by 2,3‐dimethoxybenzoic acid and 5,5’‐dimethy‐2,2’‐bipyridine: crystal structures,thermoanalysis, magnetic and fluorescence properties

A series of novel trivalent lanthanide complexes, [Ln(2,3‐DMOBA)3(5,5′‐DM‐2,2′‐bipy)]2·C2H5OH (Ln = Eu(1), Sm(2), Gd(3), Ho(4) Er(5), Pr(6), Nd(7)) (2,3‐DMOBA = 2,3‐dimethoxybenzoate, 5,5′‐DM‐2,2′‐bipy = 5,5′‐dimethy‐2,2′‐bipyridine), have been successfully synthesized and structurally validated by single crystal diffraction. All complexes discussed herein feature a binuclear structure, and contain only one free ethanol molecule, which is interesting in the lanthanide complexes. The coordination number of center Ln3+ ions is nine, showing a distorted monocapped square anti‐prismatic coordination geometry. Through a pair of alternating identical C‐H···O hydrogen bonding interactions between two 2,3‐DMOBA ligands on the same lanthanum binuclear unit with 5,5′‐DM‐2,2′‐bipy ligands on two neighboring units, the binuclear complexes can form one‐ The thermal analysis of these complexes are investigated by TG‐DSC/FTIR, the result show that the decomposition process of complexes are mainly divided into four stages with the formation of the respective oxides. The visible light emission experiment of complex 1 is carried out, and the characteristic luminescence behavior of intense red light is exhibited. What'more, fluorescence lifetimes as well as the fluorescent quantum yield of complex 1 is calculated. And the magnetic properties of complexes 3–5 are also studied.