Field-Induced SMM and Visible/NIR-Luminescence Behaviour of Dinuclear LnIII Complexes with 2-Fluorobenzoate

The reaction of Ln(NO3)2·6H2O salts (Ln = Nd, Eu, Gd, Tb, Dy, Er and Yb) with 2-fluorobenzoic acid (H-2-FBz) and 1,10-phenanthroline (phen) in ethanol/water mixture allows the isolation of dinuclear compounds of the formula [Ln2(2-FBz)4- (NO3)2(phen)2] {Ln = Nd (1), Eu (2), Gd (3), Tb (4), Dy (5), Er (6)} and [Yb2(2-FBz)6(phen)2] (7). The solid-state photoluminescence study of the complexes shows the 4f-4f lanthanide transitions in the visible range, in the cases of 2, 4 and 5, and in the NIR range for 1, 6 and 7. Magnetic studies reveal field-induced single-molecule-magnet (SMM) behaviour for compounds 1, 5, 6 and 7

A Ferromagnetic Salicylaldoximate/Azide MnII2MnIII6 Cluster with an S = 17 Ground State and a Single-Molecule-Magnet Response

One new MnII 2MnIII 6 cluster exhibiting an S = 17 spin ground state and single-molecule-magnet properties has been designed linking MnIII 3-salicylaldoximate triangles and tetracoordinated MnII cations by means of end-on azido bridges. The ferromagnetic coupling has been rationalized as a function of their structural parameters

Dinuclear LnIII Complexes with 9‐Anthracenecarboxylate Showing Field‐Induced SMM and Visible/NIR Luminescence

The reaction of several Ln(NO3)3·6H2O salts with 9-anthracenecarboxylic acid (9-HAC) and 2,2′-bipyridine (bpy) in a mixture of CH3OH/H2O has allowed the isolation of the dinuclear compounds 1-6 with formula [Ln2(μ2-9-AC)4(9-AC)2(bpy)2] [LnIII = Nd (1), Eu (2), Gd (3), Tb (4), Er (5), and Yb (6)]. The molar magnetic susceptibility measurements of 1-6 in the 2-300 K temperature range indicate weak antiferromagnetic ex-. change for the isotropic GdIII compound 3. Compounds 1, 5, and 6 exhibit field-induced single-molecule magnet (SMM) behavior. The luminescence properties of compounds 1-6 in the solid state have been studied at different temperatures and show sensitization of the 4f-4f emission bands in the NIR range for compounds 1, 5, and 6

Circularly polarized luminescence on dinuclear Tb(III) and Eu(III) complexes with (S-) and (R-) 2-phenylpropionate

The reaction of Ln(NO3)(2)center dot 6H(2)O (Ln = Tb and Eu) with (S)-(+)-2-phenylpropionic acid (S-HL) and 1,10-phenanthroline (phen) in EtOH/H2O allows the isolation of the dinuclear chiral compounds of the formula [Ln(2)(S-L)(6)(phen)(2)]center dot 2.5 center dot S-HL in which Ln = Tb (S-1), Ln = Eu (S-2). The same synthesis by using (R)-(-)-2-phenylpropionic acid (R-HL) instead of (S)-(+)-2-phenylpropionic acid allows the isolation of the enantiomeric compounds with the formula [Ln(2)(R-L)(6)(phen)(2)]center dot 2 center dot 5 center dot R-HL where Ln = Tb (R-1), Ln = Eu (R-2). All compounds show sensitized luminescence. The luminescence study, including the circularly polarized luminescence spectra of the four compounds, is reported. The magnetic behavior of S-1 and S-2 is also reported

Chiral Dinuclear Ln(III) Complexes Derived from S- and R-2-(6-methoxy-2-naphthyl)propionate. Optical and Magnetic Properties.

The reaction of LnCl3·6H2O with (S)-(+)-2-(6-methoxy-2-naphthyl)propionic acid (S-HL), best known as naproxen, and 1,10-phenanthroline (phen) in EtOH allows the isolation of dinuclear chiral compounds S-1-4 of the formula [Ln2(S-L)6(phen)2]·3DMF·H2O [Ln(III) = Eu (1), Gd (2), Tb (3) and Dy (4)]. The use of the R-enantiomeric species of the HL ligand led to complexes R-1-4 with the formula [Ln2(R-L)6(phen)2]·3DMF·H2O. Compounds R- and S-1, 3 and 4 show strong sensitized metal-centred luminescence in the visible region. Moreover, Dy(III) complexes R- and S-4 display field-induced singlemolecule magnet (SMM) behaviour. For chiral and emissive compounds circularly polarized luminescence (CPL) measurements have also been performed

Compostos de coordinació magnètics i/o luminescents derivats d'elements 3d o 4f: Cercant sistemes multipropietat

[cat] Amb l’objectiu d’obtenir materials moleculars amb una o més propietats físiques tals com magnètiques, luminescents i/o quirals en aquest treball s’han obtingut nous compostos de coordinació basats en metalls de transició, concretament amb manganès, o bé amb ions lantànid trivalents Ln(III). Les propietats físiques observades en aquests complexos deriven dels propis metalls, dels lligands orgànics coordinats a aquests o bé es deuen a la cooperativitat metall-lligands. Treballant amb ions manganès i lligands salicilaldoxima (H2-salox) i azidur s’ha obtingut el compost octanuclear (Pr4N)2[MnII2MnIII6(μ3-O)2(μ1,1- N3)6(salox)6Cl2(H2O)2]·(H2O). L’estudi magnètic revela un comportament ferromagnètic global amb estat d’espín fonamental màxim de S = 17 i resposta SMM. L’estat S fonamental observat és degut a que l’acoblament ferromagnètic entre els ions Mn(II) (amb entorn tetraèdric) i Mn(III) via el pont azidur amb mode de coordinació end-on és dominant respecte a les interaccions entre els ions Mn(III) dins dels triangles. Per altra banda, s’han presentat sis compostos obtinguts a partir de diferents lligands H2-R-salox (R= H per H2-salox; 3-CH3 per H2-3-Me-salox; CH3 per H2- Me-salox; CH2CH3 per H2-Et-salox) i anions 9-antracecarboxilat (9-AC) i que presenten la unitat triangular {Mn3O(R-salox)3}-. Quan s’ha treballat amb lligands H2-salox i H2-3-Me-salox, s’ha observat que la topologia del compost obtingut canvia en funció de si hi ha presència d’ions Na+ o Cs+ degut al diferent valor de radi iònic entre aquests dos cations alcalins. Aquesta dependència estructural no s’ha observat en emprar lligands H2-Me- salox i H2-Et-salox. L’estudi magnètic revela que en tots els compostos es compleix la correlació magneto-estructural que relaciona la torsió intramolecular Mn-N-O-Mn amb el bescanvi magnètic dins aquestes unitats. S’ha observat comportament d’imant molecular en els compostos derivats dels lligands H2-Me-salox i H2-Et-salox. En tots aquests compostos s’han observat propietats luminescents derivades de la presència del lligand 9-AC. En la segona línia de recerca presentada en aquest treball, s’han obtingut nous compostos de coordinació de Ln(III) amb presència dels àcids carboxílics 9- antracecarboxílic (H-9-AC), el 2-fluorobenzoic (H-2-FBz), els (R)/(S)-(±)-2-(6- metoxi-2-naftil)propiònic (R- o S-HL1) i els (R)/(S)-(±)-2-fenilpropiònic (R- o S- HL2) i lligands secundaris N-donadors 1,10-fenantrolina (phen), 2,2’-bipiridina (bpy) o 2,2’:6’,2’’-terpiridina (terpy). En aquests tipus de compostos s’ha buscat que les propietats luminescents derivin de la sensibilització de les transicions f-f dels ions Ln(III) per part dels diferents lligands orgànics coordinats a aquests. En alguns casos s’han observat diferents estructures sota una mateixa combinació de lligands a causa de la contracció del radi iònic dels lantànids. Entre els diferents compostos de coordinació obtinguts s’ha demostrat la coexistència de propietats magnètiques i luminescents per [Ln2(9-AC)6(bpy)2] (Ln(III) = Nd, Er i Yb), [Ln2(9-AC)6(phen)2] (Ln(III) = Er i Yb), [Ln(9- AC)3(terpy)(H2O)]·H2O·DMF (Ln(III) = Er i Yb), [Ln2(2-FBz)4(NO3)2(phen)2] (Ln(III) = Nd, Dy i Er), [Yb2(2-FBz)6(phen)2] i [Ln2(2-FBz)6(terpy)2]·H-2-FBz·H2O (Ln = Nd, Dy, Er i Yb). La presència de les espècies enantiomèricament pures dels àcids carboxílics quirals R- o S-HL1 o bé R- o S-HL2 ha derivat en la obtenció dels compostos amb comportament imant, luminescents i quirals [Ln2(R-L1)6(phen)2]·3DMF·H2O i [Ln2(S-L1)6(phen)2]·3DMF·H2O (Ln(III) = Nd i Dy), [Nd2(R-L2)6(phen)2]·2.5S-HL2 [Nd2(S-L2)6(phen)2]·2.5S-HL2, [Yb2(R-L2)4(NO3)2(phen)2]·2R-HL2 i [Yb2(R- L2)4(NO3)2(phen)2]·2R-HL2. A més, també a causa de la quiralitat dels compostos induïda pels lligands carboxilat, s’ha observat luminescència circularment polaritzada en estat sòlid en els compostos [Eu2(R-L1)6(phen)2]·3DMF·H2O, [Eu2(S-L1)6(phen)2]·3DMF·H2O i en [Ln2(R-L2)6(phen)2]·2.5S-HL2 [Ln2(S- L2)6(phen)2]·2.5S-HL2 (Ln(III) = Eu i Tb).[eng] The aim of this work is to obtain molecular materials that display one or more physical properties such as magnetism, luminescence and/or chirality. Based on coordination chemistry, we have synthesised new compounds with transition metals or with lanthanide trivalent ions (Ln(III)). The physical properties observed in these compounds arise from the metals, from the ligands coordinated to them or from the metal-ligand cooperativity. We have isolated a MnII2MnIII6 compound using salicyladoxime (H2-salox) and azide (N3-) ligands. Magnetic study of this compound reveals a spin ground state of S = 17, the highest possible for this system. The stabilization of this maximum magnetic ground state is due to the dominance of the ferromagnetic exchange between the Mn(II) and Mn(III) through the N3- ligand. Continuing with manganese, a series of {Mn3O(R-salox)3}- based compounds have been obtained using H2-salox, H2-3-Me-salox, H2-Me-salox or H2-Et-salox ligands and the sodium or caesium 9-anthracenecarboxilate (9-AC) salt. A structural dependence is observed when using H2-salox or H2-3-Me-salox with Na+ or Cs+ carboxylate salt. The magnetic properties of the obtained compounds are strongly dependent on the R- group of the R-salox ligand. Luminescence properties have been observed in these compounds. On the other hand, several new Ln(III) coordination complexes have been obtained combining different carboxylic acids [H-9-AC, 2-fluorobenzoic acid (H- 2-FBz), R/S-2-(6-methoxy-2-naphthyl)propionic acid (R- o S-HL1) or R/S- phenylpropionic acid] with different N-donor secondary ligands (2,2’- bipyridine, 1,10’-phenanthroline or 2,2’:6’,2’’-terpyridine). Under these conditions, we have obtained compounds [Ln2(9-AC)6(bpy)2] (Ln(III) = Nd, Er and Yb), [Ln2(9-AC)6(phen)2] (Ln(III) = Er and Yb), [Ln(9- AC)3(terpy)(H2O)]·H2O·DMF (Ln(III) = Er and Yb), [Ln2(2-FBz)4(NO3)2(phen)2] (Ln(III) = Nd, Dy and Er), [Yb2(2-FBz)6(phen)2] and [Ln2(2-FBz)6(terpy)2]·H-2- FBz·H2O (Ln = Nd, Dy, Er and Yb) which display magnetic and luminescent properties. The use of pure enantiomeric species of R- o S-HL1 or R- o S-HL2 led to the isolation of magnetic, luminescence and chiral compounds [Ln2(R- L1)6(phen)2]·3DMF·H2O and [Ln2(S-L1)6(phen)2]·3DMF·H2O (Ln(III) = Nd and Dy), [Nd2(R-L2)6(phen)2]·2.5S-HL2, [Nd2(S-L2)6(phen)2]·2.5S-HL2 and [Yb2(R- L2)4(NO3)2(phen)2]·2R-HL2 and [Yb2(R-L2)4(NO3)2(phen)2]·2R-HL2. Moreover, chiral compounds [Eu2(R-L1)6(phen)2]·3DMF·H2O, [Eu2(S- L1)6(phen)2]·3DMF·H2O and [Ln2(R-L2)6(phen)2]·2.5S-HL2 [Ln2(S-L2)6(phen)2]·2.5S-HL2 (Ln(III) = Eu and Tb) display Circularly Polarized Luminescence

Homodinuclear lanthanide 9-anthracenecarboxylate complexes: field induced SMM and NIR-luminescence.

Six homodinuclear lanthanide complexes with formula [Ln2(l2-9-AC)4(9-AC)2(phen)2] (Ln(III) = Nd (1), Eu (2), Gd (3), Tb (4), Er (5) and Yb (6) are reported and complexes 1-3 and 6 are structurally characterized. 9-HAC = 9-anthracenecarboxylic acid, phen = 1,10-phenanthroline. The luminescence properties of compounds 1-6 have been studied at different temperatures in the solid state and show the sensitization of the 4f-4f emission bands in the NIR range for compounds 1, 5 and 6. The molar magnetic susceptibility measurements of 1-6 in the 2-300 K temperature range indicate weak antiferromagnetic exchange for the isotropic Gd(III) compound 3. Furthermore, slow relaxation of the magnetization is found in complexes 5 and 6 with effective energy barriers of 9.5 cm 1 (0.1 T) and 22.7 cm 1 (0.15 T), respectively