Polymeric cobalt(II) thiolato complexes-syntheses, structures and properties of ¹∞[Co(SMes)₂] and ¹∞[Co(SPh)₂NH₃]

Reactions of [Co(N(SiMe3)2)2thf] with 2.1 equiv. of MesSH (Mes = C6H2-2,4,6-(CH3)3) yield dark brown crystals of the one dimensional chain compound 1∞[Co(SMes)2]. In contrast reactions of [Co(N(SiMe3)2)2thf] with 2.1 equiv. of PhSH result in the formation of a dark brown almost X-ray amorphous powder of ‘Co(SPh)2’. Addition of aliquots of CH3OH to the latter reaction resulted in the almost quantitative formation of crystalline ammonia thiolato complexes either [Co(SPh)2(NH3)2] or 1∞[Co(SPh)2NH3]. Single crystal XRD reveals that 1∞[Co(SPh)2NH3] forms one-dimensional chains in the crystal via μ2-SPh bridges whereas [Co(SPh)2(NH3)2] consists at a first glance of isolated distorted tetrahedral units. Magnetic measurements suggest strong antiferromagnetic coupling for the two chain compounds 1∞[Co(SMes)2] (J = −38.6 cm−1) and 1∞[Co(SPh)2NH3] (J = −27.1 cm−1). Interestingly, also the temperature dependence of the susceptibility of tetrahedral [Co(SPh)2(NH3)2] shows an antiferromagnetic transition at around 6 K. UV-Vis-NIR spectra display d–d bands in the NIR region between 500 and 2250 nm. Thermal gravimetric analysis of [Co(SPh)2(NH3)2] and 1∞[Co(SPh)2NH3] reveals two well separated cleavage processes for NH3 and SPh2 upon heating accompanied by the stepwise formation of ‘Co(SPh)2’ and cobalt sulfide

Magnetic anisotropy in trigonal planar Fe(ii) bis(trimethylsilyl)amido complexes of the type [Fe{N(SiMe₃)₂}₂L]—experiment and theory

Systematic ac (alternating current) magnetic investigations on four new trigonal planar high-spin Fe2+ complexes [Fe{N(SiMe3)2}2L] reveal that complexes which comprise a phosphine or arsine type ligand (L =PPh3, PMe3 and AsPh3) display slow magnetic relaxation at temperatures below 8 K under applied dc(direct current) fields, whereas a complex with a phosphine oxide ligand (L = OPPh3) does not. Accordingly, the parameters characteristic for magnetic anisotropy, derived both from dc magnetic measurements and quantum chemical calculations, reveal distinct differences for these two types of complexes. Extensive ab initio calculations of multi-reference wave function type were performed on the four new complexes listed above and the related reported ones with L = py, thf and PCy3 in order to get a reasonable description of the local electronic states involved in the magnetic relaxation. These calculations confirm that strong spin–orbit effects generate the magnetic anisotropy of complexes with L = PPh3, PMe3, AsPh3 and PCy3. On the other hand, the complexes with L = OPPh3, py and THF exhibit only small spin–orbit splittings, consistent with the fast relaxation found experimentally

Near-Infrared Luminescence in Trinuclear Mixed-Metal Chalcogenolate Complexes of the Types [M2_{2}Ti(EPh)6_{6}(PPh3_{3})2_{2}] (M = Cu, Ag; E = S, Se) and [Na(thf)3_{3}]2_{2}[Ti(SPh)6_{6}]

The optical properties of four new trinuclear chalcogenolato bridged metal complexes [Ag$_{2}$Ti(SPh)$_{6}$(PPh$_{3}$)$_{2}$], [Na(thf)$_{3}$]$_{2}$[Ti(SPh)$_{6}$], [Cu$_{2}$Ti(SePh)$_{6}$(PPh$_{3}$)$_{2}$], and [Ag$_{2}$Ti(SePh)$_{6}$(PPh$_{3}$)$_{2}$] have been investigated by absorption and photoluminescence spectroscopy as well as time-dependent density functional theory (TDDFT) calculations and compared to the results published recently for [Cu$_{2}$Ti(SPh)$_{6}$(PPh$_{3}$)$_{2}$]. All of these compounds are distinguished by efficient near-infrared luminescence at ∼880–1200 nm in the solid state at low temperatures, which remains quite intense for the copper–titanium complexes at ambient temperature with PL quantum yields of 9.5 and 4.8% at λPL = 1090 and 1240 nm for [Cu$_{2}$Ti(EPh)$_{6}$(PPh$_{3}$)$_{2}$], E = S, Se, respectively. According to the calculations, a peculiar feature of the lowest-energy electronic transitions in these complexes is their high localization on the metal and chalcogen atoms, with negligible contributions of the “external” ligand groups. Correspondingly, the type of atoms in the M$_{2}$TiE$_{6}$ (M = Cu, Ag, Na) core structure determines optical properties such as the absorption and emission wavelengths and PL lifetime

A “Solvent-Free” Crystal Structure of [FeN(SiMe3)23] – Synthesis, Structure and Properties

For the synthesis of the ferric bis(trimethylsilyl)amido complex [Fe{N(SiMe3)2}3] literature gives differing synthetic protocols based on crystallization from solution. In this report we present a ‘solvent‐free’ structural phase of [Fe{N(SiMe$_{3}$)$_{2}$}$_{3}$] which was isolated by sublimation of the product obtained from the reaction of 2 eq FeCl$_{3}$ with 3 eq LiN(SiMe$_{3}$)$_{2}$ in benzene. It could be characterized by single crystal as well as powder XRD and elemental analysis. However, $_{57}$Fe Mößbauer spectroscopy suggests a contamination of the main product with an Fe(II) species. Also, a part of the solid reaction byproducts from the reactions in solution were identified by powder XRD and $_{7}$Li MAS NMR which indicate distinct redox side reactions between oxidizing FeCl$_{3}$ and reducing LiN(SiMe$_{3}$)$_{2}$, a fact which rationalizes the lower than expected yields and the observation of an Fe(II) impurity compound. AC magnetic measurements of [Fe{N(SiMe$_{3}$)$_{2}$}$_{3}$] ave been performed in an extended frequency range up to 10$^{4}$ s$^{-1}$ allowing for a more precise evaluation of the magnetic relaxation parameters when compared to previously published measurements

Experimental and theoretical evidence for low-lying excited states in [Cr6_{6}E8_{8}(PEt3_{3})6_{6}] (E = S, Se, Te) cluster molecules

Three [Cr$_{6}$E$_{8}$(PEt$_{3}$)$_{6}$] cluster molecules with E = S, Se, and Te have been synthesized by reaction of stoichiometric mixtures of Cr(II) and Cr(III) metal salts with silylated chalcogen reagents E(SiMe$_{3}$)$_{2}$ (E = S, Se, Te) in the presence of L = PEt$_{3}$ = triethylphosphine. For the sulfide- and selenide-bridged clusters two crystallographic forms (trigonal R$\bar{3}$ and triclinic P$\bar{1}$), which differ in the presence of lattice solvent molecules, have been isolated. Structural data, optical spectra and quantum chemical calculations reveal the presence of low-lying excited states in [Cr$_{6}$E$_{8}$(PEt$_{3}$)$_{6}$] (E = S, Se), which would help in rationalizing the non-vanishing magnetic moments at 2 K revealed by DC magnetic measurements and EPR spectroscopy. These findings are partially in contrast to a previous report by Saito and co-workers (S. Kamiguchi, H. Imoto, T. Saito, Inorg. Chem., 1998, 37, 6852–6857.), who postulated an incorporated hydrogen atom as the source of paramagnetism at low temperatures for the trigonal forms of [Cr$_{6}$E$_{8}$(PEt$_{3}$)$_{6}$] (E = S, Se)

catena-Poly[[bis(pyridine)­lead(II)]bis(μ-penta­fluoro­benzene­thiol­ato)]

The title compound, [Pb(C6F5S)2(C5H5N)2]n, shows the PbII atom in a ψ-trigonal bipyramidal S2N2 bonding environment. Pyridine N atoms occupy axial sites, while thiol­ate S atoms and a stereochemically active lone pair occupy equatorial sites. Very long inter­molecular Pb⋯S inter­actions [3.618 (4) and 3.614 (4) Å] yield a weakly associated one-dimensional polymeric structure extending parallel to [010]

X-ray Crystallographic Analysis of a Tailor-Made Bis(phthalocyaninato)-TbIII Single-Molecule Magnet as a Fundamental Unit for Supramolecular Spintronic Devices

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