Pyrazolylcyclohexanol Complexes of Vanadium − A Temperature- and Solvent-Dependent Monomer−Dimer Equilibrium

Abstract

The reaction of VOCl 3 with tridentate rac-trans-[1-pyrazolyl-3-(2-pyridyl)]cyclohexanol in the presence of K 2 CO 3 generates a mononuclear six-coordinate V V complex. With the bidentate ligand rac-trans-2-(pyrazol-1-yl)cyclohexan-1-ol, reduction of V V to V IV takes place to give a dinuclear complex with bridging alkoxo units; this compound is also accessible

From vanadium(V) to vanadium(IV) - and backwards

“…4. An analogous arrangement is found in the other crystallographically characterized representatives of this class of compounds, [VOCl{OCH(Me)CH 2 OMe}] 2 [2] and [VOCl{OCH 2 (C 4 H 7 O)}] 2 [3] as well as in the alkoxide-bridged oxovanadium(IV) complex [VOCl(OCy-2-py)] 2 [4] (Scheme 1). The vanadyl groups in these compounds adopt a syn position in relation to the V-O-V-O ring.…”

“…In 2001, Thiel and coworkers made similar observations [4] as Hovnanian when they reacted VOCl 3 in CH 2 Cl 2 with the bidentate ligand rac-trans-2-(pyrazol-1-yl)cyclohexan-1-ol at 0 °C in the presence of K 2 CO 3 as base to obtain an orange-brown solution. The primary product decomposed already below -20 °C.…”

Coordination compounds of N,N′-olefin functionalized imidazolin-2-ylidenes

“…The Pd-I bond lengths of 2.6423(5) and 2.6411(5) Å lie within the expected range for cis-[PdI 2 (NHC) 2 ] complexes. Compared to trans-[PdI 2 (NHC) 2 ] [16] complexes the Pd-I bonds are elongated in 5 which we attribute to the stronger transinfluence of the carbene ligand. Consequently, the Pd-C carbene bond lengths in complex 5 (1.993(4) and 2.004(4) Å ) are slightly shorter than in complexes of type trans-[PdI 2 (NHC) 2 ] [16].…”

N‐Heterocyclic Carbenes with Neutral Tethers

“…[ 169 ] in which they introduce the reaction of imidazole with cyclohexene oxide, subsequent quarternisation with methyl iodide and the derivatisation of the hydroxyl functional group to an ester (see Figure 3.59 ). [ 169 ] in which they introduce the reaction of imidazole with cyclohexene oxide, subsequent quarternisation with methyl iodide and the derivatisation of the hydroxyl functional group to an ester (see Figure 3.59 ).…”