Preparation of [Cu(NN)(PP)](+) derivatives has been systematically investigated starting from two libraries of phenanthroline (NN) derivatives and bis-phosphine (PP) ligands, namely, (A) 1,10-phenanthroline (phen), neocuproine (2,9-dimethyl-1,10-phenanthroline, dmp), bathophenanthroline (4,7-diphenyl-1,10-phenanthroline, Bphen), 2,9-diphenethyl-1,10-phenanthroline (dpep), and 2,9-diphenyl-1,10-phenanthroline (dpp); (B) bis(diphenylphosphino)methane (dppm), 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,2-bis(diphenylphosphino)benzene (dppb), 1,1'-bis(diphenylphosphino)ferrocene (dppFc), and bis[(2-diphenylphosphino)phenyl] ether (POP). Whatever the bis-phosphine ligand, stable heteroleptic [Cu(NN)(PP)](+) complexes are obtained from the 2,9-unsubstituted-1,10-phenanthroline ligands (phen and Bphen). By contrast, heteroleptic complexes obtained from dmp and dpep are stable in the solid state, but a dynamic ligand exchange reaction is systematically observed in solution, and the homoleptic/heteroleptic ratio is highly dependent on the bis-phosphine ligand. Detailed analysis revealed that the dynamic equilibrium resulting from ligand exchange reactions is mainly influenced by the relative thermodynamic stability of the different possible complexes. Finally, in the case of dpp, only homoleptic complexes were obtained whatever the bis-phosphine ligand. Obviously, steric effects resulting from the presence of the bulky phenyl rings on the dpp ligand destabilize the heteroleptic [Cu(NN)(PP)](+) complexes. In addition to the remarkable thermodynamic stability of [Cu(dpp)2]BF4, this negative steric effect drives the dynamic complexation scenario toward almost exclusive formation of homoleptic [Cu(NN)2](+) and [Cu(PP)2](+) complexes. This work provides the definitive rationalization of the stability of [Cu(NN)(PP)](+) complexes, marking the way for future developments in this field.

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The electronic and structural properties of ten heteroleptic [Cu­(NN)­(PP)]+ complexes have been investigated. NN indicates 1,10-phenanthroline (phen) or 4,7-diphenyl-1,10-phenanthroline (Bphen); each of these ligands is combined with five PP bis-phosphine chelators, i.e., bis­(diphenylphosphino)­methane (dppm), 1,2-bis­(diphenylphosphino)­ethane (dppe), 1,3-bis­(diphenylphosphino)­propane (dppp), 1,2-bis­(diphenylphosphino)­benzene (dppb), and bis­[(2-diphenylphosphino)­phenyl] ether (POP). All complexes are mononuclear, apart from those based on dppm, which are dinuclear. Experimental dataalso taken from the literature and including electrochemical properties, X-ray crystal structures, UV–vis absorption spectra in CH2Cl2, luminescence spectra and lifetimes in solution, in PMMA, and as powdershave been rationalized with the support of density functional theory calculations. Temperature dependent studies (78–358 K) have been performed for selected complexes to assess thermally activated delayed fluorescence. The main findings are (i) dependence of the ground-state geometry on the crystallization conditions, with the same complex often yielding different crystal structures; (ii) simple model compounds with imposed C 2v symmetry ([Cu­(phen)­(PX3)2]+; X = H or CH3) are capable of modeling structural parameters as a function of the P–Cu–P bite angle, which plays a key role in dictating the overall structure of [Cu­(NN)­(PP)]+ complexes; (iii) as the P–Cu–P angle increases, the energy of the metal-to-ligand charge transfer absorption bands linearly increases; (iv) the former correlation does not hold for emission spectra, which are red-shifted for the weaker luminophores; (v) the larger the number of intramolecular π-interactions within the complex in the ground state, the higher the luminescence quantum yield, underpinning a geometry locking effect that limits the structural flattening of the excited state. This work provides a general framework to rationalize the structure–property relationships of [Cu­(NN)­(PP)]+, a class of compounds of increasing relevance for electroluminescent devices, photoredox catalysis, and solar-to-fuels conversion, which so far have been investigated in an unsystematic fashion, eluding a comprehensive understanding.

Among the large variety of bioactive C60 derivatives, fullerene derivatives substituted with sugar residues, that is, glycofullerenes, are of particular interest. The sugar residues are not only solubilizing groups; their intrinsic biological properties also provide additional appealing features to the conjugates. The most recent advances in the synthesis and the biological applications of glycofullerenes are summarized in the present review article with special emphasis on globular glycofullerenes, that is, fullerene sugar balls, constructed on a hexa-substituted fullerene scaffold. The high local concentration of carbohydrates around the C60 core in fullerene sugar balls is perfectly suited to the binding of lectins through the "glycoside cluster effect", and these compounds are potential anti-adhesive agents against bacterial infection. Moreover, mannosylated fullerene sugar balls have shown antiviral activity in an Ebola pseudotyped infection model. Finally, when substituted with peripheral iminosugars, dramatic multivalent effects have been observed for glycosidase inhibition. These unexpected observations have been rationalized by the interplay of interactions involving the catalytic site of the enzyme and non-glycone binding sites with lectin-like abilities.

The synthesis of pillar[5]arene-based glycoclusters has been readily achieved by CuAAC conjugations of azido- and alkyne-functionalized precursors. The lectin binding properties of the resulting glycosylated multivalent ligands have been studied by at least two complementary techniques to provide a good understanding. Three lectins were selected from bacterial pathogens based on their potential therapeutic applications as anti-adhesives, namely LecA and LecB from Pseudomonas aeruginosa and BambL from Burkholderia ambifaria. As a general trend, multivalency improved the binding to lectins and a higher affinity can be obtained by increasing to a certain limit the length of the spacer arm between the carbohydrate subunits and the central macrocyclic core.

Whereas the reaction of 1,4-bis(2-bromoethyloxy)benzene (4) with paraformaldehyde in the presence of BF 3 ·Et 2 O afforded exclusively the cyclopentameric pillar[5]arene derivative (5), both cyclopenta-and cyclohexameric macrocycles 5 and 6 were obtained when the reaction of 4 with paraformaldehyde was performed at 45°C in CHCl 3 with FeCl 3 as the catalyst. Treatment of compounds 4-6 with sodium azide provided the corresponding polyazides, to which a cyanobiphenyl building block was subsequently grafted to generate model compound 1, pillar[5]arene 2, and pillar[6]arene 3, bearing two,

A synthetic approach combining recent concepts for the preparation of multifunctional nanomolecules (click chemistry on multifunctional scaffolds) with supramolecular chemistry (self‐assembly to prepare rotaxanes) gave easy access to a large variety of sophisticated [2]rotaxane heteroglycoclusters. Specifically, compounds combining galactose and fucose have been prepared to target the two bacterial lectins (LecA and LecB) from the opportunistic pathogen Pseudomonas aeruginosa.

Comparison of the liquid-crystalline properties of a pillar [5]arene core functionalized with 10 mesogenic cyanobiphenyl units with those of a corresponding model compound revealed the strong influence of the macrocyclic pillar [5]arene core on the mesomorphic properties. Pillar[n]arenes are unique tubular-shaped macrocyclic compounds made of 1,4-disubstituted hydroquinone subunits linked by methylene bridges in their 2,5-positions.1 They are usually prepared from 1,4-dialkoxybenzene derivatives and paraformaldehyde in the presence of a Lewis acid catalyst.2 Owing to the reversibility of the Friedel-Crafts reaction, the cyclooligomerization is thermodynamically driven thus allowing the preparation of pillar[n]arenes in high yields.3 Depending on the solvent and/or the Lewis acid catalyst, the major cyclooligomerization product is either the cyclopentamer (n = 5) or the cyclohexamer (n = 6).4 Whereas significant research efforts have been devoted to the study of inclusion complexes obtained from pillar [5]arenes, 1 their tubular shape has not been exploited so far. With its unique pentagonal rigid structure, the pillar[5]arene moiety appears to be an attractive core unit for the preparation of novel liquid-crystalline materials with unconventional shape. It is known that isolated molecules with point groups displaying 5-fold symmetry must reduce their symmetry when forming crystalline monolayers.5 Thus, pentagon-shaped subunits within closely packed smectic layers may result in orientational and/or positional disorder. As a result, the crystalline phase may be destabilized but, at the same time, the intermolecular interactions between neighboring pentagon-shaped moieties should contribute to the stabilization of the liquid-crystalline phase. With this idea in mind, we have prepared a pillar[5]arene core decorated with cyanobiphenyl moieties. Comparison of its liquid-crystalline properties with those of a corresponding model compound revealed the dramatic influence of the macrocyclic pillar[5]arene core on the mesomorphic properties.The synthetic approach to the pillar[5]arene derivative relies on the copper-catalyzed alkyne-azide cycloaddition (CuAAC) reaction used to introduce the mesomorphic subunits on both rims of the macrocyclic core. This methodology has proven to be a powerful procedure for the grafting of multiple mesogens onto a compact multifunctional core unit 6 and clickable pillar [5]arene building blocks are easily available.7 As shown in Scheme 1, pillar [5]arene derivative 3 was obtained in two steps from compound 1.Treatment of 1 and paraformaldehyde with BF 3 ÁEt 2 O in 1,2-dichloroethane gave pillar [5]arene 2 in 40% yield.8 Under these conditions, no traces of the corresponding pillar[6]arene derivative could be detected. Subsequent reaction with sodium azide in DMF at room temperature gave clickable building block 3 in 97% yield. 9 Owing to the high number of azide Scheme 1 Synthesis of clicked pillar[5]arene derivatives 5a-c.