Immobilization of
palladium(II) acyclic diaminocarbene (Pd(II)-ADC)
complexes on a resin support surface has been easily performed by
metal-mediated addition of amino groups of benzhydrylamine-polystyrene
to the coordinated isocyanide ligand of cis-PdCl2(CNR)2 (R = t-Bu, Cy). The investigation
of the benzhydrylamine reaction with palladium-coordinated isocyanides
in solution has revealed that, depending on the reaction conditions,
two carbene-type complexes can be obtained as a result of the addition
to the CN triple bond, as well as a third complex which is formed
via substitution of the isocyanide ligand by benzhydrylamine. Nucleophilic
addition of an amino group to the isocyanide ligand has led to a cis-acyclic
diaminocarbene complex or a cationic diaminocarbene complex with trans
configuration and an intramolecular hydrogen-bonded chloride anion
(the nature of this noncovalent interaction was analyzed by DFT calculations,
including AIM analysis). The unsupported and resin-supported palladium
catalysts have demonstrated high catalytic activity in both Sonogashira
and Suzuki–Miyaura cross-coupling. The supported catalyst can
be recovered and repeatedly reused without a significant loss in efficiency.
The degree of the palladium binding with polystyrene, the oxidation
state, and the palladium leaching level were investigated by XPS and
XRF analyses.
Well-defined diazotates are scarce. Here we report the synthesis of unprecedented homoleptic palladium(II) diazotate complexes. The palladium(II)-mediated nitrosylation of 2-aminopyridines with NaNO results in the formation of metal-stabilized diazotates, which were found to be cytotoxic to human ovarian cancer cells.
Two types of immobilized on the amino-functionalized polystyrene-supported acyclic diaminocarbene palladium complexes (ADC-Pd II ) are investigated under Sonogashira cross-coupling conditions. Depending on substituents in the diaminocarbene fragment immobilized ADC-Pd II , systems are found to have different catalytic activity and stability regarding Pd-leaching. Pd II -diaminocarbenes possessing protons at both nitrogen atoms smoothly decompose into Pd 0 -containing species providing a catalytic "cocktail system" with high activity and ability to reuse within nine runs. Polymer-supported palladium (II) complex bearing NBn-C carbene -NH-moiety exhibits greater stability while noticeably lower activity under Sonogashira cross-coupling. Four molecular ADC-Pd II complexes are also synthesized and investigated with the aim of confirming proposed base-promoted pathway of ADC-Pd II conversion through carbodiimide into an active Pd 0 forms.
A new convenient approach to the synthesis of useful N-heterocyclic carbene complexes of group 13 metals was successfully developed. We demonstrate that air-stable copper(I) diaminocarbene complexes are excellent carbene transfer...
The Fischer-Tropsch process (F-T process) is known as a method of synthesizing organic products (including liquid fuel) from CO + H2 mixture gases (synthesis gas) using various catalysts. The interest in the F-T process is associated with the global struggle against carbon emissions. Earlier we noted that the electrochemical synthesis of formic acid from water and atmospheric CO2 can be a promising general scheme for obtaining "green fuel" with minus (negative) "carbonic effect" simultaneously "formate cycle" (synthesis of organic products from formic acid produced from atmospheric CO2) fuel has zero carbon balance. This synthesis is brought to efficiency, surpassing natural photosynthesis. Synthesized formic acid can be used as a fuel for fuel cells and as a hydrogen accumulator. A semiproduct of green fuel synthesis with zero carbon balance and synthetic organic chemical products with minus carbon balance (thanks to bonded carbon from atmospheric CO2). From an economical point the direct use of formic acid would be more rational (with the exception of one stage), without first carbon monoxide separation. From the point of view of the physical chemistry, it is necessary to take into account the relatively low reactivity of formic acid in comparison with carbon monoxide. The traditional way of activation, by applying high temperatures, high pressures and specific catalysts in gas phase. However, using electromagnetic activation may be a more interesting pathway. This aspect will be discussed in this work. The final selection of the method based on the results of bench scale should be made on the basis of a complex criterion of the rate of passage of the modified F-T process and economic indicators: equipment cost, and energy consumption in terms of the mass of final products, taking into account of their cost. In this case, it appears an alternative way of obtaining some final products without using fossil hydrocarbons.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.