111-41-1Relevant articles and documents
Multifunctional compact zwitterionic ligands for preparing robust biocompatible semiconductor quantum dots and gold nanoparticles
Susumu, Kimihiro,Oh, Eunkeu,Delehanty, James B.,Blanco-Canosa, Juan B.,Johnson, Brandy J.,Jain, Vaibhav,Hervey, William Judson,Algar, W. Russ,Boeneman, Kelly,Dawson, Philip E.,Medintz, Igor L.
, p. 9480 - 9496 (2011)
We describe the synthesis of a series of four different ligands which are used to prepare hydrophilic, biocompatible luminescent quantum dots (QDs) and gold nanoparticles (AuNPs). Overall, the ligands are designed to be compact while still imparting a zwitterionic character to the NPs. Ligands are synthesized appended to a bidentate dihydrolipoic acid- (DHLA) anchor group, allowing for high-affinity NP attachment, and simultaneously incorporate tertiary amines along with carboxyl and/or hydroxyl groups. These are placed in close proximity within the ligand structure and their capacity for joint ionization imparts the requisite zwitterionic nature to the nanocrystal. QDs functionalized with the four different compact ligands were subjected to extensive physical characterization including surface charge, wettability, hydrodynamic size, and tolerance to a wide pH range or high salt concentration over time. The utility of the compact ligand coated QDs was further examined by testing of direct conjugation to polyhistidine-appended protein and peptides, aqueous covalent-coupling chemistry, and the ability to engage in Foerster resonance energy transfer (FRET). Conjugating cell penetrating peptides to the compact ligand coated QD series facilitated their rapid and efficient cellular uptake, while subsequent cytotoxicity tests showed no apparent decreases in cell viability. In vivo biocompatibility was also demonstrated by microinjecting the compact ligand coated QDs into cells and monitoring their stability over time. Inherent benefits of the ligand design could be extended beyond QDs as AuNPs functionalized with the same compact ligand series showed similar colloidal properties. The strong potential of these ligands to expand NP capabilities in many biological applications is highlighted.
TWO-STEP PROCESS FOR CONVERTING CYCLIC ALKYLENE UREAS INTO THEIR CORRESPONDING ALKYLENE AMINES
-
Page/Page column 21; 22, (2019/02/25)
The invention pertains to a process for converting cyclic alkyleneureas into their corresponding alkyleneamines, comprising - in a first step converting cyclic alkyleneureas into their corresponding alkyleneamines by reacting cyclic alkyleneureas in the liquid phase with water with removal of CO2, so as to convert between 5 mole% and 95 mole% of alkyleneurea moieties in the feedstock to the corresponding amines, and - in a second step adding an inorganic base and reacting cyclic alkylene ureas remaining from the first step with the inorganic base to convert them partially or completely into their corresponding alkyleneamines. It has been found that the two-step process of the present invention makes it possible to still obtain a high conversion of cyclic alkyleneureas, while using substantially less strong inorganic base. The process according to the invention also shows a higher selectivity to amines than the prior art process.
PROCESS FOR CONVERTING CYCLIC ALKYLENE UREAS INTO THEIR CORRESPONDING ALKYLENE AMINES
-
Page/Page column 21-22; 19-20, (2019/02/25)
The invention relates to a process for converting one or more cyclic ethylene ureas into corresponding ethylene amines and carbon dioxide. In the process, water is contacted with one or more cyclic alkylene urea compounds comprising one or more cyclic alkylene urea moieties in a reaction vessel at a temperature of 150 to 400°C, optionally in the presence of an amine compound selected from the group of primary amines, cyclic secondary amines and bicyclic tertiary amines. The mole ratio of water to cyclic alkylene urea moieties is in the range of from 0.1 to 20. In the reaction, at least a portion of the cyclic alkylene urea moieties are converted to corresponding alkylenediamine moieties and carbon dioxide, and the carbon dioxide is removed from the liquid reaction mixture in a stripping vessel by feeding a stripping fluid to the stripping vessel, and removing a carbon dioxide-containing stripping fluid.
