The reactivity of the reduced ZrIIICo0 heterobimetallic complex [(thf)Zr(MesNPiPr2)3CoN2] (1a) towards O–H, S–H, S–S, and O–O bonds has been investigated. Complex 1a reacts readily with PhOH, EtOH, and H2O to generate the one‐electron‐oxidized complexes [(RO)Zr(MesNPiPr2)3CoN2] [R = Et (2), Ph (3), H (4)]. In contrast, PhSH and PhS–SPh react by means of overall two‐electron processes to form [(η2‐MesNPiPr2)Zr(μ‐SPh)(MesNPiPr2)2Co(SPh)] (5a). Addition of stoichiometric diethyl peroxide to 1a generates 2, but further equivalents lead to the two‐electron oxidized product [(EtO)Zr(MesNPiPr2)3Co(OEt)] (6). More sterically hindered peroxides such as dicumyl peroxide or di‐tert‐butyl peroxide do not react with 1a under ambient conditions, but upon photolysis, di‐tert‐butyl peroxide reacts with 1a to form [(tBuO)Zr(MesNPiPr2)3CoN2] (7). These results imply that an inner‐sphere electron‐transfer process is occurring at the Zr site of 1a upon treatment with these chalcogen‐based substrates, and a dissociative electron‐transfer mechanism is proposed.

Stabilizing colloids or nanoparticles in solution involves a fine balance between surface charges, steric repulsion of coating molecules, and hydration forces against van der Waals attractions. At high temperature and electrolyte concentrations, the colloidal stability of suspensions usually decreases rapidly. Here, we report a new experimental and simulation discovery that the polysaccharide (dextran) coated nanoparticles show ion-specific colloidal stability at high temperature, where we observed enhanced colloidal stability of nanoparticles in CaCl2 solution but rapid nanoparticle-nanoparticle aggregation in MgCl2 solution. The microscopic mechanism was unveiled in atomistic simulations. The presence of surface bound Ca2+ ions increases the carbohydrate hydration and induces strongly polarized repulsive water structures beyond at least three hydration shells which is farther-reaching than previously assumed. We believe leveraging the binding of strongly hydrated ions to macromolecular surfaces represents a new paradigm in achieving absolute hydration and colloidal stability for a variety of materials, particularly under extreme conditions.

The relative stability constants of Tb(III) complexes exhibiting binding to a series of 4-substituted analogues of dipicolinic acid (2,6-pyridinedicarboxylic acid) (DPA) were calculated using density functional theory (DFT) with the standard thermodynamic cycle. DFT calculations showed that the strengths of the stability constants were modified by the substituents in the following (decreasing) order: −NH2 > −OH ∼ −CH2OH > −imidazole ∼ −Cl ∼ −Br ∼ −H > −F > −I, with the differences among them falling within one to two log units except for −NH2. Through population and structural analysis, we observed that the −NH2, −OH, −CH2OH, and halide substituents can donate electrons via resonance effect to the pyridine ring of DPA while inductively withdrawing electrons with different strengths, thus resulting in the different binding strengths of the 4-substituted DPAs to the Tb(III) ions. We believe that these observations possess utility not only in the ongoing development of luminescent probes for bioanalytical studies but also for more recent cross-industrial efforts to enhance reservoir surveillance capabilities using chemical tracers within the oil and gas sector.

We are developing an integrated, real-time system for deploying Advanced Tracers cost-effectively in a ubiquitous and potentially long-term way. This campaign is for the sake of increasing the oil recovery factor in large waterflooded reservoirs through improved optimization of the water injection for oil production. This paper explains key features of this novel system and reports main results from the ongoing field test of our second-generation tracer material and detection methodology. Existing inter-well tracers require elaborate laboratory processing for analysis and are not compatible with ubiquitous or real-time deployment. Additionally, conventional tracer material and service costs are not economically viable for widespread and long-term deployment; also, available material barcodes compatible with carbonate reservoirs may be inadequate to monitor dozens of wells simultaneously. Our system addresses all of these inadequacies using novel materials and detection methods, with detailed modeling studies providing strong justification of the financial benefit of this tracer deployment through quantification of increased oil recovery from waterflooded reservoirs. Key elements of this new inter-well Advanced Tracers system include: An optically-detectable tracer material that can in principle be detected in real-time or near real-time at low limits of detection (LODs), even in the presence of background oil in producing water by means of an intrinsic oil background-subtraction method. The material also has high mobility in high-salinity carbonate reservoirs.A rich palette of tracer barcodes (potentially 50 - 100 or more) to enable simultaneous injection and sampling in dozens of nearby wells.Modeling feasibility studies, performed on an ensemble of different reservoir geometries and with sensitivity analyses, showing that including routine inter-well tracer data along with injection and production rates improves the history match quality and therefore, the optimization of the water injection and oil extraction rates so as to achieve a few percent increase in net present values (NPV). Recent field tests of the detectability and discrimination of injected prototype tracer materials will be described. This work adapts novel technology development at the state of the art of modern nanotechnology and bioanalysis to the long-term reservoir stewardship objectives. The integrated, real-time tracer-detection system promises financial benefits through increased NPV and/or ultimate recovery factor via better optimization of water injection.

Environmental tracing applications require materials that can be detected in complex fluids composed of multiple phases and contaminants. Moreover, large libraries of tracers are necessary in order to mitigate memory effects and to deploy multiple tracers simultaneously in complex oil fields. Herein, we disclose a novel approach based on the thermal decomposition of polymeric nanoparticles comprised of styrenic and methacrylic monomers. Polymeric nanoparticles derived from these monomers cleanly decompose into their constituent monomers at elevated temperatures, thereby maximizing atom economy wherein the entire nanoparticle mass contributes to the generation of detectable units. A total of ten unique single monomer particles and three dual-monomer particles were synthesized using semicontinuous monomer starved addition polymerization. The pyrolysis gas chromatography-flame ionization detection/mass spectrometry (GC-FID/MS) behavior of these particles was studied using high-pressure mass spectrometry. The programmable nature of our methodology permits simultaneous removal of contaminants and subsequent identification and quantification in a single analytical step.