MoIV3-Polyoxomolybdates with frustrated Lewis pairs for high-performance hydrogenation catalysis

Abstract

Highly efficient catalytic hydrogenation of the MOIV6-γ-Keggin hybrid with MoIV–O–MoVIO multiple Lewis pairs has been established.

Metal–metal bonds in polyoxometalate chemistry

“…The original motivation in Xu's work was the development of hydrogenation catalysts based on frustrated Lewis pair systems that involve highly reduced POMs with partial clusterlike and partial metal-oxo features. 112,113,116 In this line, the γisomer of [Mo IV 6Mo VI 7O32(OH)4(C5H5N)6] 2− is a representative system that has shown an exceptional heterogeneous catalytic conversion of nitrobenzene to aniline with a yield of over 99% under mild conditions (Figure 7.b). 116 The Xu group has elaborated that in the presence of protic solvents and hydrazine, the pyridine ligands of the Mo IV site are replaced, and the POM is then activated.…”

“…112,113,116 In this line, the γisomer of [Mo IV 6Mo VI 7O32(OH)4(C5H5N)6] 2− is a representative system that has shown an exceptional heterogeneous catalytic conversion of nitrobenzene to aniline with a yield of over 99% under mild conditions (Figure 7.b). 116 The Xu group has elaborated that in the presence of protic solvents and hydrazine, the pyridine ligands of the Mo IV site are replaced, and the POM is then activated. Following this, it is being proposed that a hydrazine molecule approaches a pair of Mo IV sites that has a nature of a Lewis acid.…”

1T-MoS2catalysed reduction of nitroarenes and a one-pot synthesis of imines

“…[17][18][19][20][21] The notable drawbacks of using molecular hydrogen gas as a hydrogen source are the requirements of high temperature and pressure with the help of specialized reaction vessels/setup. This proviso can be eluded using various other hydrogen sources, such as formic acid, 22,23 ammonia borane, 9,[24][25][26] silane, 27 ammonium salt, 28,29 sodium borohydride, [30][31][32][33][34] and hydrazine monohydrate, 8,[35][36][37][38] for the corresponding reduction of nitroaromatics in contrast to the conventional conditions.…”

Ionothermal Synthesis of an Antimonomolybdate Cluster, [Sb8MoVI13MoV5O66]5–, and Its Catalytic Behavior to the Reduction of Nitrobenzene

“…The direct reduction of aromatic nitro compounds is one of the principal methods to obtain aromatic amines, and much effort has been devoted to developing efficient catalysts with cost-effectiveness for the reduction. − Reductions catalyzed by Lewis acid/base and ILs have been proven in previous works. − Very recently, Xu’s group employed mixed-valence POMo as the catalyst to reduce the aromatic nitro compound and receive an unexpected result of high catalytic performance. ,, In view of the structure made up of a Lewis base anion of a mixed-valence antimonomolybdate cluster and IL cations of EMIm, an excellent catalytic activity to the reduction should be anticipated for 1-Sb 8 Mo 18 .…”

“…45−47 Very recently, Xu's group employed mixed-valence POMo as the catalyst to reduce the aromatic nitro compound and receive an unexpected result of high catalytic performance. 29,48,49 In view of the structure made up of a Lewis base anion of a mixed-valence antimonomolybdate cluster and IL cations of EMIm, an excellent catalytic activity to the reduction should be anticipated for 1-Sb 8 Mo 18 .…”