Synthesis and Structural Characterization of Non‐Homoleptic Carbamato Complexes of V^V and W^VI and Their Facile Implantation onto Silica Surfaces

Abstract

The vanadium(V) amido-carbamato derivatives VO(NR 2 )(O 2 CNR 2 ) 2 (R = Me, 1; Et, 2) are obtained by the reaction of VOCl 3 with preformed carbamato species (ammonium or sodium carbamates). The synthesis of an ionic ammonium chlorido-amide of W VI , 3, is performed using WOCl 4 and diethylamine as precursors. Moreover, the reactivity of 3 with CO 2 is investigated. Mixed W VI chlorido-carbamato compounds, 4 and 5, are obtained by the reaction of WOCl 4 with stoichiometric amounts of sodium diethylcarbamate. All of the products are [a]

Recent Advances in the Chemistry of Metal Carbamates

“…Concerning metal alkyls, lithium N,N-dialkylcarbamates were recently prepared starting from n BuLi and CO 2 in the presence of diisopropylamine or pyrrole [165]. A related reaction was reported with NaH, providing a more convenient pathway to Na(O 2 CNEt 2 ) compared to the use of sodium sand [166]. Additionally, in these cases, intermediacy of the in situ formed metal amide is conceivable.…”

“…with NaH, providing a more convenient pathway to Na(O2CNEt2) compared to the use of sodium sand [166]. Additionally, in these cases, intermediacy of the in situ formed metal amide is conceivable.…”

“…More in general, metal chlorido complexes can be used as precursors for the installation of carbamato unit(s) [166,171,[231][232][233] Other metal compounds, such as Dy(III) [235], Fe(II) [236], Cu(II) [237][238][239][240][241], Ni(II) [239] and Zn(II) [240][241][242][243] perchlorates, nitrates and sulfates, uranyl diacetate [244] Other metal compounds, such as Dy(III) [235], Fe(II) [236], Cu(II) [237][238][239][240][241], Ni(II) [239] and Zn(II) [240][241][242][243] perchlorates, nitrates and sulfates, uranyl diacetate [244] or [Pd(MeCN) 4 ] 2+ [245] were used as starting materials for the preparation of carbamato derivatives. The reactions are usually carried out in polar organic solvents (MeOH, MeCN) in the presence of amines, polyamines or aza-macrocyclic ligands under CO 2 atmosphere (Scheme 23a).…”

“…Recently, the study of the reactivity of homoleptic N,N-dialkylcarbamates with silica has been extended to Cu(II), Nb(III), Nb(V), Ta(V), Tb(III) and Eu(III) derivatives [131,153,362,363]. Silica grafting has been also realized with non-homoleptic complexes of group 4 and 5 metals, wherein the carbamato ligands are the most reactive ones [166,234,290]. Even magnetite nanoparticles [364] and silica/zirconia [362] have been decorated with metal carbamates.…”

“…TiCl 4 with one equivalent of preformed [TMG][O 2 CNEt 2 ] (TMG = tetramethylguanidine), leading to the trinuclear [TiCl 2 (O 2 CNEt 2 ) 2 ] 3[109]. Interestingly, the co-product is not the expected guanidinium chloride but the hexachlorometalate [TMG] 2 [TiCl 6 ] (probably formed via addition of chlorides to unreacted TiCl 4 ), which can be easily removed by filtration.More in general, metal chlorido complexes can be used as precursors for the installation of carbamato unit(s)[166,171,[231][232][233]. In this setting, treating TiCp* 2 Cl, VOCl 3 and NbOCl 3 with pre-carbonated amines respectively allowed the isolation of [TiCp* 2 (O Drawings based on published data[220,221,225,227,228], H atoms omitted for clarity.…”