Dyspnea and Palliative Care in Advanced Chronic Obstructive Pulmonary Disease: A Rapid Review.

Dyspnea is the most common and activity-limiting symptom for those with chronic obstructive pulmonary disease (COPD). Treatment is complex, palliative care (PC) dyspnea relief interventions are poorly understood, and PC remains underutilized in COPD despite national guidelines and recommendations. The purpose of this rapid review was to explore the concept of dyspnea and role of PC through the lens of providers, caregivers, and patients with COPD.

Ligand Chirality Transfer from Solution State to the Crystalline Self-Assemblies in Circularly Polarized Luminescence (CPL) Active Lanthanide Systems.

The synthesis of a family of chiral and enantiomerically pure pyridyl-diamide (pda) ligands that upon complexation with europium [Eu(CFSO)] result in chiral complexes with metal centered luminescence is reported; the sets of enantiomers giving rise to both circular dichroism (CD) and circularly polarized luminescence (CPL) signatures. The solid-state structures of these chiral metallosupramolecular systems are determined using X-ray diffraction showing that the ligand chirality is transferred from solution to the solid state. This optically favorable helical packing arrangement is confirmed by recording the CPL spectra from the crystalline assembly by using steady state and enantioselective differential chiral contrast (EDCC) CPL Laser Scanning Confocal Microscopy (CPL-LSCM) where the two enantiomers can be clearly distinguished.

Formation of Enantiomerically Pure Luminescent Triple-Stranded Dimetallic Europium Helicates and Their Corresponding Hierarchical Self-Assembly Formation in Protic Polar Solutions.

Ditopic helicate ligands and were synthesized for the formation of dinuclear Eu luminescent chiral helical assemblies (Eu·L) in competitive organic and protic solvent media. Spectroscopic analysis revealed formation of the 2:3 (Eu·L) and 2:2 (Eu·L) species in methanolic solutions. Circular dichroism and circularly polarized luminescence (CPL) spectroscopy confirmed the chiral purity of the helical systems, while scanning electron microscopy imaging demonstrated the formation of hierarchical self-assemblies with spherical morphologies.

Chiral luminescent lanthanide complexes possessing strong (samarium, Sm) circularly polarised luminescence (CPL), and their self-assembly into Langmuir-Blodgett films.

The lanthanide directed self-assembly of chiral amphiphilic 2,6-pyridinedicarboxylic acid based ligands 1 and 2 with various Ln(CFSO) (Ln = Tb, Sm, Lu, Dy) salts was studied in CHCN and evaluated with the expected 1 : 3 and 1 : 1 Ln : Ligand species forming in solution. Ligand chirality was retained and transferred, as depicted by circular dichroism (CD) and circularly polarised luminescence (CPL) measurements (for Tb and Sm), to the lanthanide centre upon complexation with high dissymmetry factor values for the Sm complexes obtained (g = -0.44 and 0.

The effect of the linker size in C-symmetrical chiral ligands on the self-assembly formation of luminescent triple-stranded di-metallic Eu(iii) helicates in solution.

Chiral lanthanide-based supramolecular structures have gained significant importance in view of their application in imaging, sensing and other functional purposes. We have designed chiral C2-symmetrical ligands (L) based on the use of two 2,6-pyridine-dicarboxylic-amide moieties (pda), that differ from one another by the nature of the diamine spacer groups (from 1,3-phenylenedimethanamine (1(S,S), 2(R,R)) and benzene-1,3-diamine (3(S,S), 4(R,R)) to much bulkier 4,4'-(cyclohexane-1,1-diyl)bis(2,6-dimethylaniline) (5(S,S), 6(R,R))) between these two pda units. The self-assembly between L and Eu(iii) ions were investigated in CH3CN solution at low concentration whereby the changes in the absorbance, fluorescence and Eu(iii)-centred emission spectra allowed us to model the binding equilibria occurring in the solution to the presence of [Eu:L2], [Eu2:L2], [Eu2:L3] assemblies and reveal their high binding constant values.

Circularly Polarized Luminescence from Helically Chiral N,N,O,O-Boron-Chelated Dipyrromethenes.

Helically chiral N,N,O,O-boron chelated dipyrromethenes showed solution-phase circularly polarized luminescence (CPL) in the red region of the visible spectrum (λem (max) from 621 to 663 nm). The parent dipyrromethene is desymmetrised through O chelation of boron by the 3,5-ortho-phenolic substituents, inducing a helical chirality in the fluorophore. The combination of high luminescence dissymmetry factors (|glum | up to 4.

Chiroptical Probing of Lanthanide-Directed Self-Assembly Formation Using btp Ligands Formed in One-Pot Diazo-Transfer/Deprotection Click Reaction from Chiral Amines.

A series of enantiomeric 2,6-bis(1,2,3-triazol-4-yl)pyridines (btp)-containing ligands was synthesized by a one-pot two-step copper-catalyzed amine/alkyne click reaction. The Eu(III) - and Tb(III) -directed self-assembly formation of these ligands was studied in CH3 CN by monitoring their various photophysical properties, including their emerging circular dichroism and circularly polarized luminescence. The global analysis of the former enabled the determination of both the stoichiometry and the stability constants of the various chiral supramolecular species in solution.

Lanthanide directed self-assembly of highly luminescent supramolecular "peptide" bundles from α-amino acid functionalized 2,6-bis(1,2,3-triazol-4-yl)pyridine (btp) ligands.

Ligands containing the [2,6-bis(1,2,3-triazol-4-yl)pyridine] (btp) motif have recently shown promise in coordination chemistry. The motif is synthesized via the Cu(I)-catalyzed "click" reaction and can be conveniently functionalized when compared to other terdentate chelating motifs. Ligand 1 was synthesized and shown to sensitize Eu(III) and Tb(III) excited states effectively.

The application of chiroptical spectroscopy (circular dichroism) in quantifying binding events in lanthanide directed synthesis of chiral luminescent self-assembly structures.

The binding of asymmetrical and optically pure tridentate ligands ( = and ) containing one carboxylic group and 2-naphthyl as an antenna to lanthanide ions ( = La(iii) and Eu(iii)) was studied in CHCN, showing the successive formation of , and stoichiometric species in solution. The europium complexes were also synthesised, structurally characterised and their photophysical properties probed in CHOH and CHCN. The changes in the chiroptical properties of both and were used (by circular dichroism (CD) spectroscopy) to monitor the formation of these chiral self-assemblies in solution.

Probing the effects of ligand isomerism in chiral luminescent lanthanide supramolecular self-assemblies: a europium "Trinity Sliotar" study.

"Trinity Sliotar" family: Chiral ligands containing pyridyl and naphthalene moieties were synthesized and characterized. These ligands were successfully used for the synthesis of Eu(III) bundles where chirality of the ligand is successfully transferred onto the lanthanide centre resulting in circularly polarized red luminescence.

A chiral probe for the acute phase proteins alpha-1-acid glycoprotein and alpha-1-antitrypsin based on europium luminescence.

Reversible and selective binding of a dynamically racemic europium(III) complex to α(1)-acid glycoprotein and α(1)-antitrypsin is characterised by a significant change in the europium total emission spectral fingerprint and the switching on of a large circularly polarised luminescence (CPL) signal from the metal centre. Observation of an induced CD into the ligand chromophore in the presence of α(1)-AGP allows a structure for the protein-bound complex to be postulated. A direct determination of elevated α(1)-AGP levels in human serum was achieved by monitoring changes in the intensity ratio of Eu emission bands.

Synthesis of luminescent homo-dinuclear cationic lanthanide cyclen complexes bearing amide pendant arms through the use of copper catalysed (1,3-Huisgen, CuAAC) click chemistry.

The design and synthesis of dinuclear-lanthanide complexes possessing triazole-based bridges, formed by using copper catalysed 1,3-cycloaddition reactions between heptadentate alkyne functionalised cyclen europium or terbium complexes and di-azides (CuAAC reactions), are described. While this click reaction worked well for the formation of the homo-Eu(III) and Tb(III) bis-tri-arm cyclen N,N-dimethyl acetamide complexes, 2Eu and 2Tb, and for the homo-Eu(III) chiral N-methylnaphthalene based complexes 3Eu (S,S,S) and 4Eu (R,R,R), the formation of the Eu(III) complex of the primary amide analogue of 2, namely 1Eu, was not successful, clearly demonstrating the effect that the nature of the pendant arms has on this reaction. Furthermore, the click reactions between the free alkyne cyclen bis-derivatives (5-8) and the di-azide were unsuccessful, most likely due to the high affinity of the cyclen macrocycles for Cu(II).

Lanthanide directed self-assembly synthesis and photophysical evaluation of chiral Eu(III) luminescent "half-helicates".

The reaction between the asymmetrical pyridyl ligands 3 (R) and 4 (S) and Eu(III) in CH(3)CN give rise to the formation of lanthanide luminescent 'half-helicates' in 1 : 3 (Ln:ligand) stoichiometry; the formation of which was observed by monitoring the changes in the ground and the excited state properties of the ligands, and in the time-resolved Eu-centred and the CPL emission.

Metal-directed synthesis of enantiomerially pure dimetallic lanthanide luminescent triple-stranded helicates.

The synthesis and photophysical evaluation of two enatiomerially pure dimetallic lanthanide luminescent triple-stranded helicates is described. The two systems, formed from the chiral (R,R) ligand 1 and (S,S) ligand 2, were produced as single species in solution, where the excitation of either the naphthalene antennae or the pyridiyl units gave rise to Eu(III) emission in a variety of solvents. Excitation of the antennae also gave rise to circularly polarized Eu(III) luminescence emissions for Eu(2):1(3) and Eu(2):2(3) that were of equal intensity and opposite sign, confirming their enantiomeric nature in solution providing a basis upon which we were able to assign the absolute configurations of Eu(2):1(3) and Eu(2):2(3).

Comparative study of the constitution and chiroptical properties of emissive terbium and europium complexes with a common tetraazatriphenylene sensitiser; the nature of the sensitiser determines quenching sensitivity and cellular uptake.

Six pairs of Eu(III) and Tb(III) complexes of macrocyclic ligands, incorporating a common tetraazatriphenylene sensitiser, have been examined in terms of their solution structure, sensitivity to excited state quenching, protein affinity, cell toxicity and preliminary cell localisation profiles. A complex with three (S)-phenylalanine-derived ligating groups possesses distinctive 1H NMR, Eu emission and circularly polarised emission properties, consistent with a unique A-configuration in the 9-coordinate complex, where an amide carbonyl group occupies the capping position of the coordination polyhedron. Each complex possesses similar sensitivity to quenching by ascorbate, urate and iodide, has similar toxicity behaviour and shows a common intracellular localisation profile that is consistent with compartmentalisation in lysosomes or late endosomes.

Enantioselective regulation of a metal complex in reversible binding to serum albumin: dynamic helicity inversion signalled by circularly polarised luminescence.

The helicity of the (SSS)-Delta enantiomer of a terbium and europium(III) complex is inverted on reversible binding to 'drug site II' of serum albumin, signalled by a switch in its circularly polarised emission; no such behaviour occurs with the (RRR)-Lambda complexes, thereby defining a unique chiroptical probe of albumin binding.

Cobalt(II) citrate cubane single-molecule magnet.

An investigation of the magnetic properties of the cobalt(II) citrate cubane [C(NH 2) 3] 8{Co 4(cit) 4}.4H 2O reveals that the cluster is a new cobalt(II) single-molecule magnet, with an energy barrier to reorientation of the magnetization, Delta E/ k B = 21 K, and tau 0 = 8 x 10 (-7) s. The compound displays distinct, frequency-dependent peaks in the out-of-phase (chi'') component of the ac magnetic susceptibility and magnetization versus field hysteresis loops that are temperature and sweep rate dependent.

Synthesis and binding properties of hybrid cyclophane-azamacrocyclic receptors.

Three new azamacrocyclic-cyclophane hybrid receptors L(1), L(2), and L(3) have been synthesized that incorporate either 1,4,7,10-tetraazacyclododecane (cyclen) or 1,4,7-triazacyclononane (tacn) unit(s) tethered via a short amidic spacer to an electron donor and a H-bonding crown ether polycycle. The crown ether is designed to act as a host toward biologically relevant guests, whereas the macrocycle can coordinate a zinc(II) or a copper(II) ion. The pK(a) of this bound water in the zinc(II) complex of L(1) and L(2) is approximately 7.