A hemicryptophane with a triple-stranded helical structure.

A hemicryptophane cage bearing amine and amide functions in its three linkers was synthesized in five steps. The X-ray molecular structure of the cage shows a triple-stranded helical arrangement of the linkers stabilized by intramolecular hydrogen bonds between amide and amine groups. The chirality of the cyclotriveratrylene unit controls the propeller arrangement of the three aromatic rings in the opposite part of the cage.

Remarkable effect of iridium cyclometalation on the nonlinear absorption properties of a quadrupolar imine ligand.

A new type of dinuclear iridium complex, based on a quadrupolar Schiff base ligand, is synthesized and its structure fully characterized. Its linear and nonlinear spectroscopic properties are investigated, evidencing a strong contribution of the metal-to-ligand transitions not only to the linear absorption but also to the two- and three-photon absorption properties.

Efficient dibenzo[c]acridine helicene-like synthesis and resolution: scaleup, structural control, and high chiroptical properties.

Herein, we describe our recent expeditious synthesis of dibenzo[c]acridine helicene-like compounds on a large scale in pure enantiomeric form. This flexible synthesis allows for variation at several positions on the skeleton. Geometrical parameters related to these compounds have been obtained from monocrystal X-ray structure resolution.

Inherently chiral phosphonatocavitands as artificial chemo- and enantio-selective receptors of natural ammoniums.

Inherently chiral phosphonatocavitands with various bridging moieties at their wide rim were synthesized. Optical resolution by chiral HPLC was performed with cavitand 8 to afford enantiopure compounds (+)-8 and (-)-8. The molecular structures of hosts 8 and 12 were determined by X-ray diffraction.

Near-infrared nitrofluorene substitued aza-Boron-dipyrromethenes dyes.

The synthesis, spectroscopic properties, and TD-DFT calculations of new aza-Boron-dipyromethene dyes featuring pendant nitrofluorenylethynyl substituents are described. This functionalization allows for moving the luminescence in the NIR, conserving a good quantum yield efficiency.

Restricted guest tumbling in phosphorylated self-assembled capsules.

ABii diphosphonatocavitands self-assemble in chloroform solution to form dimeric molecular capsules. The molecular capsules can incarcerate an N-methylpyridinium or N-methylpicolinium guest. We have demonstrated that the supramolecular assembly acts as a molecular rotor as a result of the restricted motion of the guest inside the molecular cavity.

Fluorescence and FTIR Spectra Analysis of Trans-A₂B₂-Substituted Di- and Tetra-Phenyl Porphyrins.

A series of asymmetrically substituted free-base di- and tetra-phenylporphyrins and the associated Zn-phenylporphyrins were synthesized and studied by X-ray diffraction, NMR, infrared, electronic absorption spectra, as well as fluorescence emission spectroscopy, along with theoretical simulations of the electronic and vibration structures. The synthesis selectively afforded trans-A₂B₂ porphyrins, without scrambling observed, where the AA and BB were taken as donor- and acceptor-substituted phenyl groups. The combined results point to similar properties to symmetrically substituted porphyrins reported in the literature.

Continuous symmetry breaking induced by ion pairing effect in heptamethine cyanine dyes: beyond the cyanine limit.

The association of heptamethine cyanine cation 1(+) with various counterions A (A = Br(-), I(-), PF(6)(-), SbF(6)(-), B(C(6)F(5))(4)(-), TRISPHAT) was realized. The six different ion pairs have been characterized by X-ray diffraction, and their absorption properties were studied in polar (DCM) and apolar (toluene) solvents. A small, hard anion (Br(-)) is able to strongly polarize the polymethine chain, resulting in the stabilization of an asymmetric dipolar-like structure in the crystal and in nondissociating solvents.

A new class of C3-symmetrical hemicryptophane hosts: triamide- and tren-hemicryptophanes.

The first hemicryptophanes derived from tris(N-alkyl-carbamoylmethyl)amine and tris(2-aminoethyl)amine (tren) have been synthesized following a single synthetic pathway that allows the subsequent formation of the two heteroditopic hosts 3 and 4. X-ray crystal structures show a well-defined cavity encapsulating a solvent guest for both compounds emphasizing their complexation properties.

Self-complementary phosphonate cavitands.

iii-Phosphorylated cavitands incorporating an N-methylpyridinium guest moiety as the fourth bridging unit form supramolecular associations by inclusion of the charged CH(3)N(+)-pyridinium head into a neighboring host cavity. The dimeric association is favored in solution and was characterized by NMR, mass spectrometry, DOSY experiments, and single crystal X-ray analysis.

A rational design of catechol-based compounds: an experimental and theoretical study of optical properties.

The synthesis and optical properties of 4,5-disubstituted (tert-butyldimethylsilyloxy)-protected catechol derivatives are reported. One or two carbon-carbon triple bond functions were introduced through the Sonogashira cross-coupling reaction. The effects on the optical properties of monosubstitution at the 4-position or disubstitution at the 4- and 5-positions of these catechol derivatives with electron-withdrawing or -donating substituents have been investigated.

Structure, magnetic properties, polarized neutron diffraction, and theoretical study of a copper(II) cubane.

The paper reports the synthesis, X-ray and neutron diffraction crystal structures, magnetic properties, high field-high frequency EPR (HF-EPR), spin density and theoretical description of the tetranuclear CuII complex [Cu4L4] with cubane-like structure (LH2=1,1,1-trifluoro-7-hydroxy-4-methyl-5-aza-hept-3-en-2-one). The simulation of the magnetic behavior gives a predominant ferromagnetic interaction J1 (+30.5 cm(-1)) and a weak antiferromagnetic interaction J2 (-5.

Stable near-infrared anionic polymethine dyes: structure, photophysical, and redox properties.

The concept of cyanine has been successfully extended to an anionic heptamethine dye featuring tricyanofuran (TCF) moieties in terms of structure, reactivity, and photophysical properties. Importantly, absorption and emission are red-shifted compared to its classical cationic analog without any cost in terms of thermal stability. In addition to its "cyanine" behavior, this molecule exhibits further redox properties: oxidation and reduction led to the reversible formation of radical species whose absorption is in marked contrast with that of cyanines.

Structure, magnetism, and theoretical study of a mixed-valence Co(II)3Co(III)4 heptanuclear wheel: lack of SMM behavior despite negative magnetic anisotropy.

A mixed-valence Co(II)/Co(III) heptanuclear wheel [Co(II)3Co(III)4(L)6(MeO)6] (LH2 = 1,1,1-trifluoro-7-hydroxy-4-methyl-5-aza-hept-3-en-2-one) has been synthesized and its crystal structure determined using single-crystal X-ray diffraction. The valence state of each cobalt ion was established by bond valence sum calculations. Studies of the temperature dependence of the magnetic susceptibility and the field dependence of the magnetization evidence ferromagnetic interactions within the compound.

A mixed-valence polyoxovanadate(III,IV) cluster with a calixarene cap exhibiting ferromagnetic V(III)-V(IV) interactions.

A series of compounds (cat)[V6O6(OCH3)8(calix)(CH3OH)] was obtained under anaerobic conditions and solvothermal reaction of VOSO4 with p-tert-butylcalix[4]arene (calix) in methanol using different types of bases (Et4NOH, NH4OH, pyridine, Et3N). All compounds contain the same polyoxo(alkoxo)hexavanadate anion [V6O6(OCH3)8(calix)(CH3OH)]- (1) exhibiting a mixed valence {VIIIVIV5O19} core with the so-called Lindqvist structure coordinated to a calix[4]arene macrocycle and cocrystallizing with the conjugated acid of the base (cat = Et4N+, NH4(+), pyridinium, Et3NH+) involved in the synthesis process. The structures have been fully established from X-ray diffraction on single crystals and the mixed valence state has been confirmed by bond valence sum calculations.

Nickel(II) chain with alternating end-on/end-to-end single azido bridges: a combined structural, magnetic, and theoretical study.

The reaction of a tridentate Schiff base LH (L-: 1,1,1-trifluoro-7-(dimethylamino)-4-methyl-5-aza-3-hepten-2-onato) with a Ni(II) salt in the presence of azide salt has led to a new alternating end-on (EO)/end-to-end (EE) azido-bridged Ni(II) chain of formula {[Ni2(micro1,1-N3)(micro1,3-N3)(L)2(MeOH)2]}n. Its originality lies in the presence of single EE and EO coordination modes for the azide. It crystallizes in the C2/c space group, a=21.

Cubane variations: syntheses, structures, and magnetic property analyses of lanthanide(III)-copper(II) architectures with controlled nuclearities.

Starting from a molecular cubane [Cu(4)L(4)] (1, with LH(2) = 1,1,1-trifluoro-7-hydroxy-4-methyl-5-aza-hept-3-en-2-one), we successfully replaced one and then two copper(II) ions of the cubane core by lanthanide ions to elaborate new families of 3d-4f complexes. Here, we report the syntheses, crystal structures, magnetic properties, and theoretical description of the tetranuclear copper(II) complex [Cu(4)L(4)] (1, [Cu(4)]) together with original yttrium(III) and gadolinium(III) heterometallic derivatives: [YCu(3)L(3)(hfac)(3)](-) (2, [YCu(3)]); [GdCu(3)L(3)(hfac)(3)](-) (3, [GdCu(3)]); [Y(3)Cu(6)L(6)(OH)(6)(MeOH)(6)(H(2)O)(6)](3+) (4, [Y(3)Cu(6)]); [Gd(3)Cu(6)L(6)(OH)(6)(MeOH)(6)(H(2)O)(6)](3+) (5, [Gd(3)Cu(6)]). 1 crystallizes in the P2(1)/c monoclinic space group with a cubane-like structure and shows ferromagnetic behavior.

Ferromagnetic interaction in an asymmetric end-to-end azido double-bridged copper(II) dinuclear complex: a combined structure, magnetic, polarized neutron diffraction and theoretical study.

A new end-to-end azido double-bridged copper(II) complex [Cu(2)L(2)(N(3))2] (1) was synthesized and characterized (L=1,1,1-trifluoro-7-(dimethylamino)-4-methyl-5-aza-3-hepten-2-onato). Despite the rather long Cu-Cu distance (5.105(1) A), the magnetic interaction is ferromagnetic with J= +16 cm(-1) (H=-JS(1)S(2)), a value that has been confirmed by DFT and high-level correlated ab initio calculations.

Large pressure-induced red shift of the luminescence band originating from nonstacked square-planar [Pt(SCN)4]2- in a novel trimetallic complex.

Luminescence of the novel trimetallic complex {Pt(SCN)2[(mu-SCN)Mn(NCS)(bipy)2]2} originates from a d-d transition of the square-planar [Pt(SCN)4]2- moiety. The band maximum shows a red shift of -99 cm(-1) kbar(-1) under external pressure up to 32 kbar at room temperature. This red shift is comparable to values for crystals where Pt-Pt interaction between stacked complexes is enhanced by pressure, but the crystal structure for the trimetallic complex shows that no metal-metal interaction can occur.