Cobalt on Mesoporous Silica:  The First Heterogeneous Pauson−Khand Catalyst

Abstract

Cycloaddition of alkynes with alkenes and carbon monoxide by dicobalt octacarbonyl to cyclopentenones (known as Pauson-Khand reaction) has been recognized as one of the most important methodologies to synthesize cyclopentenone derivatives. 1 Recently the catalytic version of the Pauson-Khand reaction has been developed by us and others. 2 In developing large-scale processes, it is extremely important to heterogenize homogeneous catalyst systems, because heterogeneous catalytic systems have many advantages over homogeneous counterparts in liquid-phase reactions, including easy removal of catalysts from reaction mixtures and recycling/reuse of catalysts. 3 In heterogenizing homogeneous catalyst systems, supports such as polymers, silica, and zeolites have received the most attention. 4 Recently, various mesoporous silicas with pore size ranging from 2 to 10 nm have been extensively applied as supports for many catalytically active metals and homogeneous catalysts. 5 Here we report the first heterogeneous catalyst system for Pauson-Khand reactions. The catalyst system is metallic cobalt supported on mesoporous silica.

Formation of Titanium Nitride Nanoparticles within Mesoporous Silica SBA-15

“…The incorporated nanoparticles may also have interesting catalytic, optical, and magnetic properties. [4][5][6][7][8] Hence the growth of metal and semiconductor nanomaterials in mesoporous silica has been an active area of research in recent years. Most of the studies involve the formation of metal nanoparticles and nanowires, such as Au, Ag, Pt, Pd, and Ti, within the nanoscale channels of mesoporous silica powder.…”

“…A titanium amide, tetrakis(dimethylamino)titanium or Ti(NMe 2 ) 4 , was used as the TiN source. Both Ti(NMe 2 ) 4 and Ti(NEt 2 ) 4 have been used in the chemical vapor deposition of TiN films under ammonia flow at temperatures of ∼300-550°C, and thus should represent as suitable candidates for the preparation of TiN nanoparticles within mesoporous silica SBA-15. 30,31 Pyrolysis of the metal amide in the absence of ammonia may result in greater residual carbon content in the TiN films.…”

“…30,31 Pyrolysis of the metal amide in the absence of ammonia may result in greater residual carbon content in the TiN films. 31a Thus ammonolysis during the pyrolysis reaction of Ti(NMe 2 ) 4 was used in the present study.…”

MALDI-TOF-MS analysis of small molecules using modified mesoporous material SBA-15 as assisted matrix

“…To overcome this problem, several alternative matrices, such as high mass molecules [12,13] There has been a great deal of interest in ordered mesoporous materials due to their regular pore sizes in the mesoporous range, high surface areas, high pore volumes, and easy functionalization since they were first reported in 1992 [23,24]. Recently, there have been significant advances in the preparation and modification of mesoporous materials, which allows their utilization in various applications, such as adsorbents [25], catalyst supports [26], nano-templates [27], and nanomaterials [28] for advanced electronics. In general, the pore surfaces of mesoporous silica materials are covered with a layer of silanol groups (Si-OH), which can act as the binding sites for desired functional groups via covalent grafting on the surfaces.…”

“…Recently, there have been significant advances in the preparation and modification of mesoporous materials, which allows their utilization in various applications, such as adsorbents [25], catalyst supports [26], nano-templates [27], and nanomaterials [28] for advanced electronics. In general, the pore surfaces of mesoporous silica materials are covered with a layer of silanol groups (Si-OH), which can act as the binding sites for desired functional groups via covalent grafting on the surfaces.…”