[1,2-Bis(diphenyl­phosphino)ethane]{2-[bis­(diphenyl­phosphinometh­yl)amino]pyridinium}fluoridohydrazidato­molybdenum(IV) bis­(tetra­fluoridoborate)

In the crystal structure of the title compound, [MoF(N2H2)(C31H29N2P2)(C26H24P2)](BF4)2, each Mo atom is surrounded by four P atoms of one 1,2-bis­(diphenyl­phosphino)ethane and one 2-[bis­(diphenyl­phosphinometh­yl)amino]pyridinium ligand. The remaining binding sites of the distorted octa­hedron are occupied by a hydrazidate (NNH2 2−) and a fluoride ligand. Two F atoms of an anion are disordered over two positions; the site occupancy factors are ca 0.7 and 0.3

[Bis(diphenyl­phosphino)methane-κ2 P,P′][bis­(diphenyl­phosphinometh­yl)diethoxy­silane-κ2 P,P′]bis­(dinitro­gen)­molybdenum(0) benzene 0.7-solvate

In the crystal structure of the title compound, [Mo(C25H22P2)(C30H34O2P2Si)(N2)2]·0.7C6H6, the Mo atoms are coordinated by four P atoms and two N atoms in a distorted octa­hedral mode. The two C atoms of one of the two eth­oxy groups are disordered and were refined using a split model and site-occupation factors of 0.7:0.3. The crystal structure contains a benzene solvent mol­ecule with a site occupation of 70%

Spin-Crossover Molecules on Surfaces: From Isolated Molecules to Ultrathin Films

Molecular spintronics seeks to use single or few molecules as functional building blocks for spintronic applications, directly relying on molecular properties or properties of interfaces between molecules and inorganic electrodes. Spin-crossover molecules (SCMs) are one of the most promising classes of candidates for molecular spintronics due to their bistability deriving from the existence of two spin states that can be reversibly switched by temperature, light, electric fields, etc. Building devices based on single or few molecules would entail connecting the molecule(s) with solid surfaces and understanding the fundamental behavior of the resulting assemblies. Herein, the investigations of SCMs on solid surfaces, ranging from isolated single molecules (submonolayers) to ultrathin films (mainly in the sub-10 nm range) are summarized. The achievements, challenges and prospects in this field are highlighted

Kupfer‐katalysierte Monooxygenierung von Phenolen: Evidenz für einen mononuklearen Reaktionsmechanismus

Die CuI-Salze [Cu(CH3CN)4]PF und [Cu(oDFB)2]PF mit dem sehr schwach koordinierenden Anion Al(OC(CF3)3)4− (PF), sowie [Cu(NEt3)2]PF mit dem einzigartigen, linearen Bis-Triethylamin-Komplex [Cu(NEt3)2]+ wurden synthetisiert und als Katalysatoren für die Umwandlung von Monophenolen zu o-Chinonen untersucht. Die Aktivitäten dieser CuI-Salze bei der Monooxygenierung von 2,4-Di-tert-butylphenol (DTBP-H) wurden mit denen der [Cu(CH3CN)4]X-Salze mit “klassischen” Anionen (BF4−, OTf−, PF6−) verglichen, wobei ein Anioneneffekt auf die Aktivität des Katalysators und ein Ligandeneffekt auf die Reaktionsgeschwindigkeit festgestellt wurden. Letztere wird durch den Einsatz von CuII-Semichinon-Komplexen als Katalysatoren drastisch erhöht, was darauf hinweist, dass die Bildung eines CuII-Komplexes dem eigentlichen katalytischen Zyklus vorausgeht. Diese und andere experimentelle Erkenntnisse zeigen, dass die Oxygenierung von Monophenolen mit den oben genannten Systemen nicht einem dinuklearen, sondern einem mononuklearen Weg folgt, analog zur Topachinon-Cofaktor-Biosynthese im Enzym Aminoxidase

Dinuclear Copper(I) Complexes Supported by Bis‐Tridentate N‐Donor‐Ligands: Turning‐On Tyrosinase Activity

Four structurally related bis-tridentate N-donor ligands with either two secondary amine or two imine functions were synthesized, and the corresponding dicopper(I) complexes were investigated as catalysts for the tyrosinase-like conversion of 2,4-di-tert-butylphenol (DTBP-H) to 3,5-di-tert-butylquinone (DTBQ). Notably, the imine systems show evidence for both a μ-η2 : η2-peroxo-dicopper(II) species and catalytic conversion of DTBP-H to DTBQ. Moreover, kinetic studies indicate that a dinuclear copper-oxygen species is involved in the monooxygenation of DTBP-H. In contrast, the amine systems do not show monooxygenase activity. Comparison of the experimentally determined catalytic activities with DFT-optimized geometries of μ-η2 : η2-peroxo-dicopper(II) intermediates suggests that the ligand rigidity of the imine systems allows equatorial attack of the substrate and, thus, subsequent monooxygenation whereas this is not possible in the amine systems due to the fact that no free equatorial positions are available in the μ-peroxo intermediate

Surface cis Effect : Influence of an Axial Ligand on Molecular Self-Assembly

Adding ligands to molecules can have drastic and unforeseen consequences in the final products of a reaction. Recently a surface trans effect due to the weakening of a molecule-surface bond was reported. Here, we show a surface cis effect where an axial ligand at adsorbed transition-metal complexes enables lateral bonding among the molecules. In the absence of this ligand, the intermolecular interaction is repulsive and supramolecular patterns are not observed. Fe-tetramethyl-tetraazaannulene on Au(111) was investigated using low-temperature scanning tunneling microscopy and spectroscopy along with density functional theory calculations. At low coverages, the molecules remain isolated. Exposure to CO leads to axial CO bonding and induces reordering into extended clusters of chiral molecular trimers. The changed self-assembly pattern is due to a CO-induced modification of the molecular structure and the corresponding charge transfer between the molecule and the substrate, which in turn changes the lateral intermolecular forces