Lahcène Ouahab’s research while affiliated with French National Centre for Scientific Research and other places

... It should be noted that carboxylic acid anions are often used in the chemical assembly of coordination polymers as additional bridging ligands [1,3,5,[16][17][18] or for the preorganization of homo-and heterometallic "building blocks" linked by bridging N-donor ligands [19][20][21][22]. Copper(II) carboxylate complexes are characterized by the formation of binuclear paddle-wheel motifs {Cu 2 (μ-O 2 CR) 4 } in which the Cu II ions are linked by four bridging carboxylate anions, while the axial positions of square pyramidal copper coordination polyhedra can be occupied by both solvent molecules [23][24][25][26] and anions or neutral carboxylic acid molecules [27][28][29]. ...

Reference:

Solvent-dependent formation of 1D coordination polymers based on polynuclear copper(II)-carboxylate fragments and 4-(pyridine-3-yl)methyleneamino-1,2,4-triazole linkers

... Moreover, when chirality is added to the (luminescent) SMM behavior [21][22][23][24][25][26][27][28], chiral SMM [29], ferroelectric SMM [30] as well as chiral luminescent SMM [31][32][33][34][35][36] and magneto-chiral SMM [37,38] can be obtained. To these three properties, the introduction of redox-active ligands is of interest because it could permit to switch both optical and magnetic properties depending on the oxidation state of the ligand [39][40][41][42][43][44][45][46]. One of the most used redox-active ligands is made from the tetrathiafulvalene (TTF) core because of its two mono radical and dicationic stable states which are easily accessible by chemical ways and because it can be easily decorated with one to four substituted groups able to coordinate transition metal and lanthanide ions [18,[47][48][49]. ...

Reference:

Chiral or Luminescent Lanthanide Single-Molecule Magnets Involving Bridging Redox Active Triad Ligand

... No type of ferromagnetic intermolecular exchange is observed in our case, which is the usual behaviour in view of previous results for magnetic exchange in pseudo-dimers mediated by similar hydrogen bonds, with closely related Dy···Dy distances [34][35][36]. ...

Reference:

Modulating Magnetic Performance in Dy Single Ion Magnets With N5O2 Ligands

... [1][2][3][4][5][6] Complexation between redox-active ligands and transition-metal salts is a rational approach for obtaining multistep redox-active metal complexes. Examples of redox-active ligands are ferrocene, [7][8][9][10][11][12] tetrathiafulvalene (TTF), [13][14][15] and porphyrin [16][17][18] derivatives. Ferrocene-based ligands are especially enticing because ferrocene can afford numerous useful derivatives by substitution reactions. ...

Reference:

Synthesis and Electrochemical Properties of Mixed‐Metal Triangular Complexes Based on Ferrocene‐Based Ligands and Dinuclear Arene Ruthenium Building Blocks

... For H = 0 Oe the main magnetic relaxation process is the QTM with significant Raman contribution for T > 5.5 K (Fig. S12 †) while for H = 1000 Oe the main magnetic relaxation is the Raman with a Direct contribution for T < 2.5 K (Fig. S17 †). The LF and HF contributions could be attributed to Dy(III) ions in different coordination environments 129,130 or crystallographically independent Dy(III) ions 131 but also to the presence of significant dipolar interaction. 132 In the present case, the pure phase of [(S)-1] n involved only one Dy(III) centre and the frequency dependence of the magnetic susceptibility was investigated at a field high enough to cancel the dipolar interaction. ...

Reference:

Etude des interactions supramoléculaires entre complexes de lanthanides et acides aminés : application en cristallographie des protéines

... [5][6][7][8][9][10] Nowadays, helicene chemistry is extensively investigated as these molecular scaffolds may be exploited in a highly diversified panel of applications such as metal complexes, molecular magnetism, nanorobotics, renewable energies and molecular photonics. 1,[11][12][13][14] Helicenes show indeed unique opto-electronic properties, especially when interacting with polarized light, because of their intrinsic chirality. As the helicity of the backbone can be either left-or right-handed, these molecules can exist in two different enantiomeric forms, thus providing a benchmark for the investigation of inherent chirality and chiral photonics. ...

Reference:

A rational framework to estimate the chiroptical activity of [6]Helicene Derivatives

... The ground state doublet is mainly composed of MJ = 15/2 (91%) and the orientation of the main anisotropy axis is calculated perpendicular to the plane involving the bzip fragment as expected for an oblate Dy(III) ion in a N2O6 coordination sphere ( Figure S30). [57][58][59][60][61][62] The energy gap between the GS and the first excited state decreases from 125.7 cm -1 to 98.8 cm -1 ( Figure S29 and Table S14). The calculated energy barrier of 98.8 cm -1 is higher than the effective energy barrier determined from the high temperature region of the Arrhenius plot at 0 Oe (23.6(2) cm -1 ) and 1000 Oe (50.3(7) cm -1 ) supporting the presence of significant under barrier magnetic relaxation mechanisms such as QTM and Raman. ...

Reference:

Reversible Pressure-Magnetic Modulation in a Tetrathiafulva-lene-Based Dyad Piezochromic Dysprosium Single-Molecule Magnet

... Functionalization at the 4-position of the bpp in the pyridine ring with a bromomethyl substituent was explored by the group of Pointillart in 2018 [82]. The same paper discussed both Fe(II) and Co(II) complexes of the ligand 2,6-di(pyrazol-1-yl)-4-(bromomethyl)pyridine (bppBr). ...

Reference:

Beyond Spin Crossover: Optical and Electronic Horizons of 2,6-Bis(pyrazol-1-yl)pyridine Ligands and Complexes

... However, some methods are now known for linking diketonate complexes into coordination polymers. This goal can be achieved by introducing additional donor atoms into the ligand structure (as, for example, in pyrazole- [29], imidazole- [30], or pyridinecontaining [31][32][33][34][35] β-diketones), or by using additional linker ligands, such as bis(diphenylphosphine oxides) [36][37][38][39][40][41][42], 4,4'-bipyridyl [43] or its N-oxide [44], quinone-based ligands [45], 2,2'-bipyrimidine [46] etc. Tetrakis anions [Ln(β-diketone)4] − can be polymerized by forming alkali metal salts under non-aqueous conditions [47][48][49]. In most of the mentioned cases, the dimensionality of the polymer is limited by the coordination number of the lanthanide: if in a typical complex with CN = 8 three diketonate ligands occupy six positions, then the polymer is forced to be linear. ...

Reference:

Self-Assembly of a Two-Dimensional Coordination Polymer Based on Silver and Lanthanide Tetrakis-Acylpyrazolonates: An Efficient New Strategy for Suppressing Ligand-to-Metal Charge Transfer Quenching of Europium Luminescence

... Particularly, photoinduced intramolecular electron transfer (PET) process between electron-donating TTF derivatives (D) and electron-accepting parts (A) such as fluorophores, C 60 and chelating ligands has yielded several photofunctional materials such as chemical sensors based on fluorescence probe functionalities, organic photovoltaic (OPV) cells and nonlinear optical devices [1][2][3][4][5][6][7]. Among them, to develop photoinduced conducting materials and photo-electric conversion materials, we have investigated the photofunctional materials using the TTF-based D-A type dyads containing strongly fluorescent parts such as 2, 5-diphenyl-1, 3, 4-oxadiazole (PPD) [8,9], 1, 3-benzothiazole (BTA) [10][11][12], fluorene [13,14] and 4, 4-difluoro-4-bora-3a, 4a-diaza-s-indacene (BOD-IPY) [15,16] as antennas for photoexcitation. On the other hand, since the first fabrication of organic light-emitting diodes (OLEDs) using tris(8-quinolinato)aluminum (Alq 3 , q = 8-quinolinato) [17], various kinds of 8-quinolinato transition metal complexes Mq x have attracted much attention because of their strongly fluorescent character, high thermal stability and excellent electron transport properties [18][19][20][21][22]. Furthermore, Alq 3 is reported to improve the conversion efficiency of heterojunction OPV cells by acting as a photosensitizer and buffer material [23,24]. ...

Reference:

Synthesis and Physical Properties of Tetrathiafulvalene-8-Quinolinato Zinc(II) and Nickel(II) Complexes