Synthesis and hydroformylation evaluation of Fréchet-type organometallic dendrons with N,O-salicylaldimine Rh(i) complexes at the focal point

Abstract

A series of organometallic dendrons containing N,O-salicylaldimine entities at the focal point were synthesised by reacting the N,O-salicylaldimine-functionalised Fréchet dendrons (G0, G1 and G2) with a [Rh(μ-Cl)(η2:η2-COD)]2 dimer to yield the corresponding Rh(COD) [COD = cyclooctadiene] complexes. These Rh(COD) complexes were exposed to an atmosphere of CO to yield a new class of rhodium carbonyl organometallic dendrons with Rh(CO)2 units at the focal point. All the compounds were characterised using standard spectroscopic and analytical techniques, these include nuclear magnetic resonance, infrared spectroscopy, mass spectrometry and single-crystal X-ray diffraction for compounds 1, 4 and 7. All of the complexes were evaluated in the hydroformylation of 1-octene, with excellent conversion and chemoselectivity towards aldehydes. The G0-(CO)2 catalyst precursor (7) was active in the hydroformylation of 1-octene, styrene, 7-tetradecene, methyl oleate, triolein, d-limonene and R-citronellal. The conversion and chemoselectivity towards aldehydes for 7-tetradecene, methyl oleate, triolein and d-limonene were promising. Across a particular dendron series, an increase in chemoselectivity was observed due to the dendritic effect. Mercury drop tests were performed for the G0-analogues and these confirm that the hydroformylation can be attributed to a combination of homogeneous and heterogeneous catalysis.

Comparison of an Offline SPE–GC–MS and Online HS–SPME–GC–MS Method for the Analysis of Volatile Terpenoids in Wine

“…Diastereomers containing the cis/trans double bond may be susceptible to interconversion under thermal treatment [20]. Terpenes in particular may be susceptible to this transformation, as demonstrated by multiple sources of literature [20,[57][58][59]. Hence, to confirm the thermal stability of the cis/trans diastereomers at elevated temperatures (as the samples are introduced into the GC inlet at 250 • C), the ratio was also determined by GC-FID.…”

Reusable Catalysts for Hydroformylation‐Based Reactions

“…Smith et al [61] developed a series of organometallic dendrons containing N,O-salicylaldimine entities at the focal point, which were synthesized by reacting the N,O-salicylaldiminefunctionalized Fréchet dendrons 5 (G0, G1 and G2) with a [Rh(μ-Cl)(η 2 :η 2 -cod)] 2 dimer, [cod = cyclooctadiene], to yield the corresponding Rh(I) complexes (Scheme 4). The Rh(cod) complexes 6 were exposed to an atmosphere of CO to yield a new class of rhodium carbonyl organometallic dendrons 7, with "Rh(CO) 2 " units at the focal point.…”

“…Smith et al [61] . developed a series of organometallic dendrons containing N , O ‐salicylaldimine entities at the focal point, which were synthesized by reacting the N , O ‐salicylaldimine‐functionalized Fréchet dendrons 5 (G0, G1 and G2) with a [Rh( μ ‐Cl)(η 2 :η 2 ‐cod)] 2 dimer, [cod=cyclooctadiene], to yield the corresponding Rh(I) complexes (Scheme 4).…”

Synthesis of Bifunctional Molecules for the Production of Polymers Based on Unsaturated Fatty Acids as Bioderived Raw Materials

“…Hydroformylation of oleic acid (1), especially of different esters, was already studies by many groups [21][22][23][24][25][26][27][28]. Our goal within this project was to apply a readily accessible catalyst like the Rh-TPPTS system in a biphasic reaction approach or other simple ligands such as triphenylphosphine (TPP) in order to form the resulting aldehydes derived from oleic acid (1) being needed for the subsequent steps of our cascade leading to the aminomethyl-substituted fatty acid (5) and isomers thereof.…”