Novel oxo-peroxo molybdenum(VI) complexes incorporating 8-quinolinol: synthesis, structure and catalytic uses in the environmentally benign and cost-effective oxidation method of methyl benzenes: Ar(CH3)n (n = 1, 2)

Synthesis and catalytic epoxidation potentiality of oxodiperoxo molybdenum(VI) complexes with pyridine-2-carboxaldoxime and pyridine-2-carboxylate: the crystal structure of PMePh3[MoO(O2)2(PyCO)]

“…Quite a few reports have already appeared in the area of homogenous catalytic epoxidation with hydrogen peroxide as oxidant and a wide variety of transition metal complexes as catalysts [13,15,[21][22][23][24][25]. As part of our continued interest in using oxoperoxomolybdenum complexes as oxidation catalysts, we were intrigued by previous reports [26,27] at the failure of the Mo-complexes to activate H 2 O 2 and by using a molybdenum complex, PPh 4 [MoO(O 2 ) 2 (SaloxH)] [6] (SaloxH 2 = Salicylaldoxime) as catalyst along with NaH CO 3 as cocatalyst [28,29] we were able to activate H 2 O 2 and the integrated catalyst, co-catalyst and oxidant functioned as a very efficient peroxidic epoxidation system. Inspired by this result, we reported some other peroxo complexes, which showed higher to much higher catalytic efficiencies [6][7][8][9][10] for olefin epoxidation.…”

“…The lengthening of the Mo(1)-N(18) [2.395 (2) Å ] distance in 2 compared to the typical Mo-N [2.194(3)-2.269(3) Å ] bond lengths in complexes[26,27], where the ligand nitrogen atoms coordinate the metal center equatorially reflects the Probable structure of 1. Possibility of H-bonding of H 2 O hydrogen and N-OH hydrogen with peroxo oxygens, however, cannot be ruled out…”

Oxidoperoxidotungsten(VI) Complexes with Secondary Hydroxamic Acids: Synthesis, Structure and Catalytic Uses in Highly Efficient, Selective and Ecologically Benign Oxidation of Olefins, Alcohols, Sulfides and Amines with H2O2 as a Terminal Oxidant

“…The key aspect [40,41] of such a reaction is that H 2 O 2 and hydrogen carbonate react in an equilibrium process to produce peroxymonocarbonate, HCO 4 -, which is a more reactive nucleophile than H 2 O 2 and speeds up the epoxidation reaction. Though WO(O 2 ) 2 ·2BMTHAH (also true for BPHAH, BOTHAH, BPTHAH) is not isolable in the present case, it was noted earlier [42] that the corresponding product with QOH as ligand, namely, WO(O 2 ) 2 ·2QOH, was not only isolated, but the attempted crystallization of the QOH adduct afforded the less reactive monoperoxido complex, [WO(O 2 )(QO) 2 ]. So, it may be safely presumed that the diperoxido adduct behaves as the active catalyst, [42] and the monooxidomonoperoxido complex [WO(O 2 )(hydroxamato)](1-5) as the catalyst precursor in the presence of a moderate excess of H 2 O 2 .…”

“…Though WO(O 2 ) 2 ·2BMTHAH (also true for BPHAH, BOTHAH, BPTHAH) is not isolable in the present case, it was noted earlier [42] that the corresponding product with QOH as ligand, namely, WO(O 2 ) 2 ·2QOH, was not only isolated, but the attempted crystallization of the QOH adduct afforded the less reactive monoperoxido complex, [WO(O 2 )(QO) 2 ]. So, it may be safely presumed that the diperoxido adduct behaves as the active catalyst, [42] and the monooxidomonoperoxido complex [WO(O 2 )(hydroxamato)](1-5) as the catalyst precursor in the presence of a moderate excess of H 2 O 2 . However, in the presence of a large excess of H 2 O 2 , we suggest that 7C or 8 become the active catalyst and the diperoxido adduct is the catalyst precursor.…”

Peroxo Complexes of Molybdenum(VI) Containing Mannich Base Ligands

“…1 They are widely used in stiochiometric as well as catalytic oxidation in organic and biochemistry, 2 for example in the oxidation of thioanisole, 3,4 methylbenzenes, 5 tertiaryamines, alkenes, alcohols, 6,7 bromide 8 and also in olefin epoxidations. [9][10][11][12][13] They also act as isomerisation catalysts for some allylic alcohols and have been applied to bleaching processes.…”