In: Chemistry – A European Journal, 2013, vol. 19, no. 51, p. 17517–17527
A ditopic benzobis(carbene) ligand precursor was prepared that contained a chelating pyridyl moiety to ensure co-planarity of the carbene ligand and the coordination plane of a bound octahedral metal center. Bimetallic ruthenium complexes comprising this ditopic ligand [L₄Ru-C,N-bbi-C,N-RuL₄] were obtained by a transmetalation methodology...
|
In: Dalton Transactions, 2012, vol. 41, no. 13, p. 3726-3730
Spin crossover requires cooperative behavior of the metal centers in order to become useful for devices. While cooperativity is barely predictable in solids, we show here that solution processing and the covalent introduction of molecular recognition sites allows the spin crossover of iron(III) sal₂trien complexes to be rationally tuned. A simple correlation between the number of molecular...
|
In: Inorganic Chemistry, 2011, vol. 50, no. 17, p. 8188–8196
A series of bimetallic N-heterocyclic carbene (NHC) ruthenium(II) complexes were synthesized, which comprise two [RuCl₂(cymene)(NHC)] units that are interlinked via the NHC nitrogens by alkyl chains of different length. Electrochemical characterization revealed two mutually dependent oxidation processes for the complex with a methylene linker, indicating moderate intramolecular electronic...
|
In: European Journal of Inorganic Chemistry, 2012, p. -
Oxidative addition of donor-functionalised 4-iodoimidazolium salts to palladium(0) provides a selective route for the preparation of abnormal chelating N-heterocyclic carbene complexes and enables the introduction of a variety of donor groups. The activation of the C4 position does not necessitate protection of the imidazolium C2 position, thereby leaving this site available for further...
|
In: Organometallics, 2011, vol. 30, no. 22, p. 6119–6132
Five different types of β-diketiminate ligands, bearing electron-donating to strongly electron-withdrawing substituents, were synthesized and used in the synthesis of Cp* ruthenium complexes (Cp* = η⁵-C₅Me₅). One series consists of complexes with a covalent RuIII–Cl bond, and the other series features a reduced RuII center, where the chloride is abstracted by...
|
In: Polyhedron, 2011, vol. 30, no. 17, p. 2776-2782
Readily prepared 2-, 4- and 5-bromo-3-methyl thiazolium triflates react by oxidative substitution with M(PPh₃)₄ (M = Ni or Pd) to furnish five of the expected normal and abnormal cationic thiazolylidene complexes (1a, 1b, 2a, 2b, and 3b). Carbene complex formation is accompanied by a ca. 40 ppm downfield shift of the α-N carbene carbons in Pd...
|
In: European Journal of Inorganic Chemistry, 2011, vol. 2011, no. 18, p. 2863–2868
N-Heterocyclic carbene (NHC) ruthenium complexes consisting of different donor substituents attached to the NHC ligand efficiently catalyse the transfer hydrogenation of ketones and of activated olefins in α,β-unsaturated ketones to give saturated alcohols. The most active catalyst precursor contains a tethered olefin as a hemilabile donor site. This complex also converts nitriles and,...
|
In: Organometallics, 2011, vol. 29, no. 22, p. 5821–5833
We report a thorough investigation of a series of isomeric complexes with the general formula trans-(pyridylidene)M(PPh₃)₂Cl (M = Pd, Ni). For the first time, a systematic comparison of normal, abnormal, and remote bonding modes is presented. X-ray structural and ¹³C NMR data indicate the importance of carbenoid mesomeric contributions in their compound class....
|
In: Organometallics, 2011, vol. 30, no. 5, p. 1021–1029
Palladation of N3-alkylated 1,2,3-triazolium salts with Pd(OAc)₂ afforded a μ²−I₂ bridged bimetallic complex [Pd(trz)I₂]₂ and monometallic bis(carbene) complexes Pd(trz)₂I₂ as a mixture of trans and cis isomers (trz = 1,2,3-triazol-5- ylidene). Addition of excess halide or modification of the palladation procedure from direct functionalization to a transmetalation...
|
In: Dalton Transactions, 2011, vol. 40, no. 12, p. 2716-2719
Main-chain C,N-protected histidine has been successfully alkylated at both side-chain nitrogens. The corresponding histidinium salt was metallated with ruthenium(II) by a transmetalation procedure, thus providing histidine-derived NHC ruthenium complexes. These bio-inspired complexes show appreciable activity in the catalytic transfer hydrogenation of ketones.
|