Formation of bis[bis(3,5-di-tert-butylcatecholato)oxomolybdenum(VI)] and related stable molybdenum-catechol complexes

Cooperative reduction by Ln2+ and Cp*− ions: synthesis and properties of Sm, Eu, and Yb complexes with 3,6-di-tert-butyl-o-benzoquinone

“…4,5 Moreover, two Eu 2+ centres in complex 3 should be liable to oxidation; the approaches to oxidize the Ln centres in the paramagnetic complexes are well described for ytterbocene derivatives. 10,11,21 It should be noted that the electrochemistry of 3,5-dbbq and its complexes with transition metals has been well studied, [43][44][45][46][47] while for 3,6-dbbq only several complexes of main group elements are characterized. 48 To study the redox behaviour, CV measurements of all complexes were performed.…”

In situ grafting of cyclopentadienyl-molybdenum complexes on mesoporous materials: The reaction of [η5-CpMo(CO)3]−Na+ with surface fixed iodo-benzyl siloxane

“…A variety of molybdenum (VI) complexes are known to be versatile catalysts for the oxidation of organic substrates [1][2][3][4][5][6][7][8][9]. Molybdenum based catalysts were applied for the industrial epoxidation of propylene, utilizing tbutyl hydroperoxide (TBHP) as oxidizing agent since the late 1960s [10,11].…”

“…Recently, cyclopentadienyl molybdenum complexes of formula Cp 0 MoO 2 Cl (Cp = C 5 R 5 ; R = H, CH 3 ) were found to be efficient homogeneous catalysts for epoxidation of alkenes with TBHP as the oxidant [23][24][25][26]. Furthermore, it became clear that the direct application of their carbonyl precursor compounds of formula CpMo(CO) 3 Cl leads to equally efficient catalysts, since the carbonyl complexes are in situ oxidized -also by TBHP -to their oxo and/peroxo congeners [23][24][25][26]. The carbonyl precursor compounds can be stored for long times without any problems while the oxides are somewhat more sensitive [23][24][25][26].…”

“…The carbonyl precursor compounds can be stored for long times without any problems while the oxides are somewhat more sensitive [23][24][25][26]. Additionally, Cp 0 Mo(CO) 3 R complexes (R = alkyl) and their oxidized congeners are also known and already successfully utilized as homogeneous catalysts or catalyst precursors [27]. However, industrial interest is still to a significant degree focused on heterogeneous catalysts due to their advantages, e.g., easier product/catalyst separation [28][29][30].…”

“…Another strategy for the confinement of metal centres in mesoporous silicates is the covalent attachment of organometallic or coordination compounds to form hybrid materials [39][40][41][42][43]. Recently, modified MCM-41 and MCM-48 materials were synthesized by grafting MoO 2 X 2 (X = Cl, Br) and CpMo-(CO) 3 Cl, the latter being quite efficient homogeneous epoxidation catalysts [23][24][25][26]43]. Additionally, surfacefixed bidentate Lewis bases have been used to bind Mo(VI) complexes as described by Gonçalves et al [44][45][46][47][48] and, independently, by Thiel et al [49][50][51] Silylation using Me 3 SiCl to remove residual Si-OH groups, which was considered to be favourable for the catalytic reaction on the surface of the mesoporous material [39][40][41][42], reduced the catalyst leaching significantly [49][50][51].…”