Berechnung der thermodynamischen Funktionen der Methylderivate von Aluminium und Gallium in gasförmigem Zustand

Nach den Molekülkonstanten wurden die thermodynamischen Funktionen der gasförmigen Monomere EMenCl3-n (E = Al, Ga, n = 0, 1, 2, 3) bei 298,15, 333, 413 K und einem Druck von 101,325 kPa berechnet. Die Normalschwingungen des Gerüsts und die Schwingungen der CH-Fragmente sind annähernd unabhängig voneinander. Die Normalschwingungen des Gerüsts wurden durch Vergleich berechnet. Als Ausgangsfrequenzen wurden die Frequenzen AlCl3, GaCl3, [AlCl4] und [GaCl4] benutzt

Yttrium Complexes Supported by Linked Bis(amide) Ligand: Synthesis, Structure and Catalytic Activity in the Ring-Opening Polymerization of Cyclic Esters

International audienc

An organolanthanide(III) single-molecule magnet with an axial crystal-field: influence of the Raman process over the slow relaxation

Here, we report the synthesis and magnetic properties investigation of a series of new organometallic homoleptic complexes Li(DME)3[Ln(DAD)2] (Ln = Dy (1a, 1b), Tb(2), and Er(3)) based on paramagnetic Ln(iii) ions coordinated by an ene-diamido[2,6-iPr2C6H3N-CH[double bond, length as m-dash]CH-NC6H3iPr2-2,6]2- (DAD) ligand. Dy-based compounds exhibit a genuine single-molecule magnet (SMM) behaviour, while the Tb3+ analogue shows a field-induced slow relaxation of the magnetisation.status: publishe

Bis(Guanidinate) Alkoxide Complexes of Lanthanides: Synthesis, Structures and Use in Immortal and Stereoselective Ring-Opening Polymerization of Cyclic Esters

International audienc

Indirect Magnetic Exchange between <i>o</i>‑Iminosemiquinonate Ligands Controlled by Apical Substituent in Pentacoordinated Gallium(III) Complexes

A number of pentacoordinated gallium complexes iSQ₂GaR (<b>1</b>–<b>7</b>) (R = Et (<b>1</b>), Me (<b>2</b>), N₃ (<b>3</b>), Cl (<b>4</b>), Br (<b>5</b>), I (<b>6</b>), NCS (<b>7</b>)) where iSQ is a radical anion of 4,6-di-<i>tert</i>-butyl-<i>N</i>-(2,6-diisopropylphenyl)-<i>o</i>-iminobenzoquinone were synthesized, and crystalline samples of <b>1</b>–<b>7</b> were characterized using magnetic susceptibility measurements. The character of magnetic exchange interaction between spins of <i>o</i>-iminosemiquinonate radicals was found to be strongly influenced by the nature of the apical substituent. The antiferromagnetic coupling is predominant when the apical position is occupied by halogens or other tested inorganic anions, and the value of exchange interaction parameter varies from −99 to −176 K for R = I and NCS, respectively. In the case of alkyl groups the ferromagnetic exchange prevails and, as the result, the triplet ground state for pentacoordianted biradical compounds was observed. Compounds <b>1</b>–<b>7</b> demonstrate a biradical X-band EPR spectrum in frozen toluene matrix. The molecular structures of <b>4</b>, <b>6</b>, and <b>7</b> have been established by single-crystal X-ray analysis. A computational DFT UB3LYP/6-31G­(d,p) study was performed on complexes <b>1–7</b> in order to understand the reason for changes in the magnetic behavior of the related diradical gallium compounds. The calculations showed that the magnetic behavior of the complexes with inorganic anions is conditioned by the presence of antiferromagnetic exchange channel formed as a consequence of overlapping between donor atomic orbitals of iminoquinone with π-orbitals of halogen atoms (<b>4</b>–<b>6</b>) or nitrogen atom (<b>3</b>, <b>7</b>)