•Dual-function metal complexes possess both diagnostic and therapeutic properties in a single molecular entity.•Design strategies for transition metal complexes-based cancer diagnostics.•Structural ...design, mechanisms of action and strategies for different theranostic modalities.
Cancer is an aggressive disease involving abnormal cell growth with the potential to invade other parts of the body. Despite intense interest from clinicians and biomedical researchers, the lack of complete understanding of the mechanisms of both the development and recurrence of cancer remains one of the greatest challenges in cancer therapy. With the continuous advancement of modern healthcare, the theranostic approach, which is regarded as the combination of therapy and diagnosis, has been viewed as a possible tool aiding the transformation of conventional, non-specific medicine towards contemporary precision or personalized medicine. Compared with traditional diagnostic modalities such as magnetic resonance imaging (MRI) and radionuclide imaging, optical imaging possesses a number of notable advantages that renders it as an attractive diagnostic modality. Among optical sensors, transition metal complexes have attracted recent attention as alternatives to conventional dyes due to their advantages of large Stokes shifts, long lifetimes, and ease of structural modifications. Representative examples of design strategies for transition metal complexes for cancer diagnostics and theranostics are discussed in this review, including chemo-theranostic, photo-triggered theranostic, targeted theranostic and combination theranostic strategies.
The polynuclear complex Cu2(naphac)2(OH)2 consists of isolated Cu ladders in which square planar CuO4 and square-pyramidal CuO5 units are linked alternately along the crystalline a direction through ...their corners, and the resultant two adjacent Cu alternating chains connect each other through edges of the CuO5 units to form a ladder. The temperature dependence of the magnetic susceptibility above 50 K is reproduced by the calculation of the spin-1/2 two-leg honeycomb spin ladder model with almost zero exchange coupling between two legs of ladder. This is explained by the Jahn-Teller elongation of square-pyramidal CuO5 units. The absence of lambda-shaped peak in the specific heat down to 1.9 K suggests the existence of large quantum fluctuations of the spin owing to low-dimensional antiferromagnetic interactions.
We have determined the crystal structures of new Co(II) polynuclear complex Co(sba)(H2O)2·H2O (sba = 4-sulfobenzoate) (1) by X-ray crystallography. The crystal structure of 1 shows Co(II) uniform ...chains in which octahedral Co(II) centers are connected through double μ-OH2 single syn-syn μ-carboxylato bridging ligands, and these uniform chains are well separated by the sba ligands. Magnetization and magnetic susceptibility data of a single crystal of 1 taken along the different crystallographic axes suggest a large uniaxial magnetic anisotropy, the so-called Ising anisotropy, possessing large c∗-axis magnetic moments. Magnetic susceptibility data of 1 is explained by an 1D Ising ferromagnet with intra-chain exchange interaction of Jz/kB = 39.6 K.
Crystal structure and magnetization of new H2O-bridged linear chin Co complex Co(sba)(H2O)2·H2O (sba = 4-sulfobenzoate). Display omitted
•Double μ-OH2 bridged one-dimensional polynuclear complex Co(sba)(H2O)2·H2O (sba = 4-sulfobenzoate) (1) were synthesized.•The compound 1 indicates an 1D Ising-like ferromagnetism with the intra-chain ferromagnetic interaction Jz/kB = 39.6 K.•Magnetization data of a single crystal of 1 suggest a large uniaxial magnetic anisotropy.
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•Noncovalent interactions in the design of metal complex catalysts.•Role of noncovalent interactions in metal complexes catalyzed functionalization of organic compounds.•Selectivity ...dependent on a cooperative action of coordination and noncovalent interactions in intermediates and transition states.
Metal complex catalysis, in which coordination compounds are designed as catalysts for chemical transformations employing noncovalent interactions, is emerging as a powerful catalytic method for organic synthesis. One of the main advantages of metal catalysis is that coordination compounds can promote various organic transformations not only by coordination bond but also through noncovalent interactions, such as hydrogen, halogen, chalcogen, pnictogen, tetrel and triel bonds, as well as metal-metal, cation-π, anion-π, lone pair-π, π-π stacking, agostic, pseudo-agostic, anagostic, dispersion-driven, lipophilic, etc., or their cooperation. In recent years, the concept of designing metal complex catalysts with noncovalent bond donor or acceptor sites has emerged as a promising strategy for developing selective catalytic transformations. In this review we discuss several recent relevant examples on the auxiliary/crucial role of noncovalent interactions in functionalization of alkanes, alkenes, alkynes, aromatics, heterocycles, aldehydes, ketones and alcohols catalyzed by metal complexes.
Natural polysaccharides are critical to a wide range of fields (e.g., medicine, food production, and cosmetics) for their various remarkable physical properties and biological activities. However, ...the bioactivities of naturally acquired polysaccharides may be unsatisfactory and limit their further applications. It is generally known that the chemical structure exhibited by polysaccharides lays the material basis for their biological activities. Accordingly, possible structural modifications should be conducted on polysaccharides for their enhancement. Recently, polysaccharides complexed with metal ions (e.g., Fe, Zn, Mg, Cr, and Pt) have been reported to be possibly used to improve their bioactivities. Moreover, since the properties exhibited by metal ions are normally conserved, polysaccharides may be endowed with new applications. In this review, the synthesis methods, characterization methods, and bioactivities of polysaccharide metal complexes are summarized specifically. Then, the application prospects and limitations of these complexes are analyzed and discussed.
Compounds Co(L-N4R2)(dbdiox)(BPh4) (L-N4R2 = N,N′-di-alkyl-2,11-diaza3.3-(2,6)pyridinophane, R = iPr (1a), Et (2a); dbdiox = 3,5-di-tert-butyldioxolene) and M(L-N4iPr2)(dbdiox)(BPh4) (M = Mn (3a), Fe ...(4a)) have been synthesized and investigated with a view to possible valence tautomeric (VT) or spin crossover (SCO) interconversions. Single crystal X-ray diffraction data for all compounds at 100 or 130 K indicate trivalent metal cations and di-tert-butylcatecholate (dbcat2−) dioxolene ligands. Variable temperature magnetic susceptibility data for all species between 2 and 340 K are consistent with these redox states, with low spin configurations for the cobalt(III) ions and high spin for the manganese(III) and iron(III) ions. Above 340 K, compound 1a exhibits an increase in magnetic susceptibility, suggesting the onset of a VT interconversion from low spin Co(III)-dbcat to high spin Co(II)-dbsq (dbsq− = di-tert-butylsemiquinonate) that is incomplete up to 400 K. In solution, variable temperature electronic absorption spectra and Evans NMR method magnetic susceptibility data indicate reversible VT interconversions for 1a in several solvents, with the transition temperature varying with solvent. Variable temperature electronic absorption spectra are temperature-invariant for 3a and 4a, while spectra for 2a in 1,2-dichloroethane suggest the onset of a VT transition at the highest temperatures measured. Density functional theory calculations on all four compounds and literature analogues provide key insights into the relative energies of the different electromeric forms and the possibilities for VT versus SCO interconversions in this family of compounds.
Self‐Healing in Supramolecular Polymers Campanella, Antonella; Döhler, Diana; Binder, Wolfgang H.
Macromolecular rapid communications.,
September 2018, Letnik:
39, Številka:
17
Journal Article
Recenzirano
Adaption and self‐healing are two major principles in material science, often coupled with the placement of supramolecular moieties within a material. Proper molecular design can enable self‐healing ...within such materials, displaying enormous potential in technology and application. Here, basic physicochemical aspects as well as new material developments in the field are described, published after a recent review in Macromolecular Rapid Communications in 2013.
What makes a supramolecular material self‐healing? This article provides insight into this complex question, discussing the dynamics of supramolecular entities within a material, together with newly reported work in the field since 2013.
•Organic light emitting diodes (OLEDs) produced from metal complexes.•Sustainability issues are imminent.•Focus on copper and zinc complexes.•Complex preparation.•Cooperativity, chirality, and ...printing.
Organic light-emitting diodes (OLEDs) produced from metal complexes play an important role in modern electroluminescent devices. While OLEDs are being used in display various applications such as TVs, smartphones and wearables already, a drastic increase in the production volume in the next years is being expected as soon as OLED lighting applications and printed OLEDs hit the market. Given that thus far, phosphorescent iridium compounds are required to make these products, sustainability issues are imminent. To review viable alternatives, we highlight the current status of sustainable metal complexes with a special focus on copper and zinc complexes. Ligand structures and complex preparation were highlighted. We also briefly address features like cooperativity, chirality, and printing.
•Different chemical classes of dyes function as efficient sensors for metal ions.•Structure dependent coordination of metal ions to chromophoric receptors.•Modulation of electronic and/or ...physico-chemical characteristics through binding.•Material based design strategies for metal ion detection.•Highly selective and sensitive sensing of metal ions with dyes.
Recent time has witnessed unprecedented activity in the colorimetric sensing because of its low cost, practicability, selectivity as well as sensitivity. In addition to the ease in visual “naked eye” qualitative assessment of the colorimetric sensing events, the quantification can be done by resorting to spectrophotometric analysis. Additionally, a number of smart materials based on nanoparticles, carbon nanotubes, mesoporous materials, synthetic pores, conjugated polymers, etc. have been developed and used for colorimetric detection. Herein, we focus on the recent developments (last five years) in colorimetric sensing using dyes.
