4.3. Reaction Mechanism 2373 4.4. Asymmetric Synthesis 2374 4.5. Outlook 2374 5. Alternating Polymerization of Oxiranes and CO2 2374 5.1. Reaction Outlines 2374 5.2. Catalyst 2376 5.3. Asymmetric Polymerization 2377 5.4. Immobilized Catalysts 2377 6. Synthesis of Urea and Urethane Derivatives 2378 7. Synthesis of Carboxylic Acid 2379 8. Synthesis of Esters and Lactones 2380 9. Synthesis of Isocyanates 2382 10. Hydrogenation and Hydroformylation, and Alcohol Homologation 2382

Transformation of carbon dioxide.

A plethora of methods have been developed over the years so that carbon dioxide can be used as a reactant in organic synthesis. Given the abundance of this compound, its utilization in synthetic chemistry, particularly on an industrial scale, is still at a rather low level. In the last 35 years, considerable research has been performed to find catalytic routes to transform CO(2) into carboxylic acids, esters, lactones, and polymers in an economic way. This Review presents an overview of the available homogeneous catalytic routes that use carbon dioxide as a C(1) carbon source for the synthesis of industrial products as well as fine chemicals.

Transformation of Carbon Dioxide with Homogeneous Transition-Metal Catalysts: A Molecular Solution to a Global Challenge?

Several recent conceptual advances, which take advantage of the design criteria and practical techniques of molecular-level control in organic chemistry, allow preparation of well-defined polymers and nanostructured materials Two trends are clear: the realization that synthesis of complex macromolecules poses major challenges and opportunities and the expectation that such materials will exhibit distinctive properties and functions Polymer synthesis methods now being developed will yield well-defined synthetic macromolecules that are capable of mimicking many of the features of proteins (for example, three-dimensional folded structure) and other natural materials These macromolecules have far-reaching potential for the study of molecular-level behavior at interfaces, in thin films, and in solution, while also enabling the development of encapsulation, drug-delivery, and nanoscale-patterning technologies

/pdf/the-convergence-of-synthetic-organic-and-polymer-chemistries-597gx5vrt0.pdf

The Convergence of Synthetic Organic and Polymer Chemistries

https://eprints.ncl.ac.uk/file_store/production/162122/B5324BA5-F503-4BE9-947E-6F7ED01AAD04.pdf

Synthesis of cyclic carbonates from epoxides and CO2

1.1. Cancer and Early Detection
Cancer is the second most common cause of death in the United States, trailing only heart disease in incidence. Despite significant worldwide investment in research, cancer remains responsible for 1 in 4 deaths in developed countries.1 Globally, over 14 million cancer diagnoses were reported in 2012, a figure expected to increase to over 22 million cases per annum in the next two decades.2 Estimated to kill over 1/2 million U.S. citizens, and with over 1.6 million new cases predicted to be diagnosed this year,3 cancer continues to present a major, yet unmet challenge to healthcare both globally and in the United States.

Cancer emerges from our own tissues, complicating both detection and treatment methods due to the similarities between the diseased tissue and healthy tissue.4,5 Despite this fact, the mortality rate from cancer is often greatly reduced by early detection of the disease. For example, non-small-cell lung cancer is responsible for the most cancer related deaths worldwide, with patients in the advanced stages of the disease having only 5–15% and <2% 5-year survival rates for stage III and IV patients, respectively.6 In contrast, patients who start therapy in the early stages of the disease (stage I) have markedly improved survival rates, with an 80% overall 5-year survival rate.6 Consequently, early diagnosis is essential to improving cancer patient prognosis.

At present, clinical detection of cancer primarily relies on imaging techniques or the morphological analysis of cells that are suspected to be diseased (cytology) or tissues (histopathology). Imaging techniques applied to cancer detection, including X-ray, mammography, computed tomography (CT), magnetic resonance imaging (MRI), endoscopy, and ultrasound, have low sensitivity and are limited in their ability to differentiate between benign and malignant lesions.7,8 While cytology, such as testing for cervical cancer via a Pap smear or occult blood detection, may be used to distinguish between healthy and diseased cells or tissues, it is not effective at detecting cancer at early stages. Similarly, histopathology, which generally relies on taking a biopsy of a suspected tumor, is typically used to probe the malignancy of tissues that are identified through alternative imaging techniques, such as CT or MRI, and may not be used alone to detect cancer in its early stages. As such, the development of assays and methods for early detection of cancer, before the disease becomes symptomatic, presents a major challenge.

Recent research within the field of nanotechnology has focused on addressing the limitations of the currently available methods for cancer diagnosis. Certain nanoparticle probes possess several unique properties that are advantageous for use in the detection of cancer at the early stages. In this review, we will discuss the advances in the development of nanoparticle-based methods for the detection of cancer by fluorescence spectroscopy. We will divide this topic into three categories: techniques that are designed for (1) the detection of extracellular cancer biomarkers, (2) the detection of cancer cells, and (3) the detection of cancerous tissues in vivo. We will discuss these strategies within the context of the nanoparticle probe used as well as the recognition moieties applied in each approach. Ultimately, the translation of these methods from the laboratory to the clinic may enable earlier detection of cancer and could extend patient survival through the ability to administer therapeutic treatment in the early stages of the disease.

While this review provides a comprehensive overview of the nanoparticle probes that are used to detect cancer in vitro and in vivo through fluorescence, there are several other relevant reviews that may be of interest to our readers, who may refer to the references for more generalized reviews of nanomaterials used for diagnostics and therapy,9–12 or more detailed insight into the specific types of nanoparticle probes (i.e., quantum dots,13 gold nanoparticles,14,15 upconversion nanoparticles,16 polymer dots,17,18 silica nanoparticles,19 polymeric nanoparticles, 20 etc.) for cancer diagnosis.

Nanoparticle Probes for the Detection of Cancer Biomarkers, Cells, and Tissues by Fluorescence

The syntheses of several norbornene block copolymers containing oligonucleotide and ferrocenyl side chains and their use in the electrochemical detection of DNA are described Two kinds of DNA-containing block copolymers with either ferrocenyl or dibromoferrocenyl groups were prepared via ring-opening metathesis polymerization (ROMP) Based on these two distinct ferrocene derivatives, a triblock copolymer labeling strategy was developed With this strategy, the identity of DNA target can be determined by the E1/2s of the ferrocenyl moieties and the ratio of peak currents These polymers exhibit predictable and tailorable electrochemical properties, high DNA duplex stability, and unusually sharp melting transitions, which are highly desirable characteristics for DNA detection applications Significantly, single-base mismatches could be easily detected using two distinct block copolymers as dual-channel detection probes in an electrochemical DNA detection format

Polymer-DNA hybrids as electrochemical probes for the detection of DNA.

A series of (salen)tin(II) and (salen)tin(IV) complexes was synthesized. The (salen)tin(IV) complexes, (salen)SnX(2) (X = Br and I), were prepared in good yields via the direct oxidation reaction of (salen)tin(II) complexes with Br(2) or I(2). (Salen)SnX(2) successfully underwent the anion-exchange reaction with AgOTf (OTf = trifluoromethanesulfonate) to form (salen)Sn(OTf)(2) and (salen)Sn(X)(OTf) (X = Br). The (salen)Sn(OTf)(2) complex was easily converted to any of the dihalide (salen)SnX(2) compounds using halide salts. All complexes were fully characterized by (1)H NMR spectroscopy, mass spectrometry, and elemental analysis, while some were characterized by (13)C, (19)F, and (119)Sn NMR spectroscopy. Several crystal structures of (salen)tin(II) and (salen)tin(IV) were also determined. Finally, both (salen)tin(II) and (salen)tin(IV) complexes were shown to efficiently catalyze the formation of propylene carbonate from propylene oxide and CO(2). Of the series, (3,3',5,5'-Br(4)-salen)SnBr(2), 3i, was found to be the most effective catalyst (TOF = 524 h(-)(1)).

(Salen)tin complexes: syntheses, characterization, crystal structures, and catalytic activity in the formation of propylene carbonate from CO(2) and propylene oxide.

We present a rational approach for assembling diverse bioactive agents, such as DNA, proteins, and drug molecules, into core−shell multifunctional polymeric nanoparticles (PNPs) that can be internalized in human breast cancer cells. Using ring-opening metathesis polymerization (ROMP), block copolymers containing small-molecule drug segments (>50% w/w) and tosylated hexaethylene glycol segments were prepared and assembled into PNPs that allowed for the surface conjugation of single-stranded DNA sequences and/or tumor-targeting antibodies. The resulting antibody-functionalized particles were readily uptaken by breast cancer cells that overexpressed the corresponding antigens.

Multifunctional polymeric nanoparticles from diverse bioactive agents.

Second harmonic generation (SHG) is used to study oligonucleotides at aqueous/solid interfaces for the first time. Detailed thermodynamic state information for interfacial DNA single strands, namely, the interfacial charge density, the interfacial potential, and the change in the interfacial energy density, is obtained. The phosphate groups on the DNA backbone serve as intrinsic labels that do not require DNA modification other than surface attachment. This approach is broadly applicable for the investigation of DNA during its interaction with biological targets, as well as charged biopolymers in general, and has important implications for predicting and controlling macromolecular interactions, improving biodiagnostics, and understanding life processes.

DNA single strands tethered to fused quartz/water interfaces studied by second harmonic generation.

An associative equilibrium theory describing the sharp melting behavior of polymer-DNA hybrids is developed. The theory considers linear polymers with attached DNAs on each polymer that serve as "stickers" and with a two-state model governing the DNA melting equilibrium. For three or more oligonucleotides on each polymer, solutions of polymer-DNA hybrids are found to undergo phase separation at sufficiently low temperatures. The dense phase dissolves as temperature increases, which leads to a sharp increase in the fraction of non-hybridized DNA near the phase transition temperature, in agreement with experimental absorbance profiles at 260 nm. The melting temperature is predicted to have the same dependence on salt concentration as a solution of unattached DNAs and be weakly sensitive to the concentration of DNA in solution. The melting temperature is predicted to be higher than that of unattached DNA in solution, with the magnitude of the increase sensitive to the DNA hybridization cooperativity. The theoretical predictions are generally in good quantitative agreement with new experimental data (also presented here), which show the effect of the polymer-DNA hybrid length and salt concentration on the melting profiles.

Julianne M. Gibbs

Papers

Polymer-DNA hybrids as electrochemical probes for the detection of DNA.

(Salen)tin complexes: syntheses, characterization, crystal structures, and catalytic activity in the formation of propylene carbonate from CO(2) and propylene oxide.

Multifunctional polymeric nanoparticles from diverse bioactive agents.

DNA single strands tethered to fused quartz/water interfaces studied by second harmonic generation.

Sharp melting of polymer-DNA hybrids : An associative phase separation approach