Jean-Marc Planeix

Molecular tectonics: from enantiomerically pure sugars to enantiomerically pure triple stranded helical coordination network

The self-assembly between a bis-monodentate tecton based on two pyridine units connected to an enantiomerically pure isomannide stereoisomer and HgCl2 leads to the formation of an enantiomerically pure triple stranded helical infinite coordination network which was structurally characterised by X-ray diffraction on single crystal.

Photophysical, Electrochemical and Electrochromic Properties of Copper-Bis(4,4'-dimethyl,6,6'-diphenyl-2,2'- bipyridine) Complexes

Abstract The synthesis, solution and solid state structural characterization, photophysical and electrochemical properties of two redox forms of an electrochromic copper-bis(4,4′-dimethyl-6,6′-diphenyl-2,2′-bipyridine) complex, [Cu(3)2]n (n=+1, +2), are presented. Both complexes were characterized in the solid state by X-ray diffraction methods on single-crystals showing that both forms exist in a pseudo-tetrahedral coordination, and a comparison with other structures was made. Like most copper(I) complexes, the red [Cu(3)2]+ complex shows a rather weak emission (Φem=2.7×10−4, dichloromethane). The lifetime of the emitting MLCT state is 34±1 ns, as observed with time resolved emission, and transient absorption (in deoxygenated dichloromethane). Typical emission and transient absorption spectra are presented. The transient absorption spectra indicate that the MLCT state absorbs stronger than the ground state, which is relatively uncommon for metal bipyridine complexes, i.e. no ground state bleaching is observed. The green [(3)2Cu]2+ complex does not show any observable emission or transient absorption, which is a common feature for Cu(II) complexes of this type. The electronic absorption spectra of the chemically and electrochemically produced copper(I/II) complexes are identical. The repeated electrochemical conversion of the Cu(I) center into Cu(II) and vice versa does not cause any decomposition. This is consistent with a fully reversible Cu(I)/Cu(II) redox couple in the corresponding cyclic voltammogram, (E1/2 (Cu(I)/Cu(II))=+0.68 V vs. SCE=+0.23 V vs. Fc/Fc+). These observations indicate that no large structural reorganization occurs upon electrochemical timescales (sub second), and that the different ways of generating the complexes does not effect their final structure, apart from the small differences observed in the X-ray structures of both forms. These characteristics make these complexes rather well suited for their incorporation into an electrochromic display configuration.

Molecular tectonics: on the role of counter-ions in the dimensionality of silver coordination networks

The role played by different anions (XF6− (X = P, As, Sb), BF4−) on the connectivity of coordination networks formed by a combination of different silver salts and an organic tecton based on piperazine bearing two pyridine units has been studied in the crystalline phase by X-ray diffraction on single crystal. All four weakly coordinating anions lead to the formation of analogous 2-D coordination networks. For the isostructural anions XF6− (X = P, As, Sb) the crystals are isomorphous.

Molecular tectonics: generation of 2-D molecular networks by combination of coordination and hydrogen bonds

The combination of two organic tectons 1 and 2, based on a 1,4-phenylenediamine backbone functionalised with two pyridine units through amide junctions with HgCl2, leads to the formation of two types of 2-D networks, one of the purely metallo-organic type, based on only coordination bonds, and the other combining both coordination and hydrogen bonds.

Alkoxo-bridged copper(II) complexes as nodes in designing solid-state architectures. The interplay of coordinative and d10-d10 metal-metal interactions in sustaining supramolecular solid-state architectures

Four novel polymeric coordination networks have been obtained through self-assembly processes involving alkoxo-bridged copperII species as nodes, and anionic cyano-complexes as linkers: infinity2[{Cu2(pa)2}{M(CN)2}2](M=Ag, 1; Au, 2), (infinity)3[{Cu4(mea)4}{Au(CN)2}4.H2O]3, and (infinity)3[{Cu2(pa)2}{Ni(CN)4}](pa = deprotonated propanolamine; mea = deprotonated monoethanolamine). The supramolecular architectures of compounds 1, and 2 are sustained by argentophilic or strong aurophilic interactions. The solid-state architectures of 1 and 2, which are isomorphous, consist of infinite layers, constructed from binuclear alkoxo-bridged nodes and [M(CN)2]- spacers. The layers are stacked in an offset parallel mode, and are further interconnected through Ag...Ag or Au...Au contacts (1: Ag...Ag 3.015 A; 2: Au....Au 3.069 A). Compound 3 consists of unique fourfold interpenetrating diamondoid nets. The diamondoid topology is built of heterocubane {Cu4O4} nodes, which are connected by [Au(CN)2]- rods. The Cu-O distances within the {Cu4O4} node vary between 1.927(2) and 2.679(1) A, showing unsymmetric bridging of the copper atoms. Aurophilic interactions are established between the bridging and terminal [Au(CN)2]- metalloligands, and connect the interpenetrating nets, resulting in infinite chains of gold atoms (the Au...Au distances vary between 3.253 and 3.305 [Angstrom]). Compound 4 exhibits a 3-D network constructed from {Cu2(pa)2]2+ nodes connected by square-planar [Ni(CN)4]2- ions. Compounds 1, 2 and 4 are weakly paramagnetic. The cryomagnetic investigation of reveals a gradual increase, followed by a decrease of the chiMT product, as the temperature is lowered. A superposition of ferro- (J1=+20.8 cm(-1)) and antiferromagnetic (J2=-6.4) interactions within the tetranuclear node was found. Antiferromagnetic interactions are established between the tetranuclear nodes (theta=-2.99 K).

Molecular tectonics and supramolecular chirality: rational design of hybrid 1-D and 2-D H-bonded molecular networks based on bis-amidinium dication and metal cyanide anions

Using the bis-amidinium dication 1 bearing four acidic protons disposed in a divergent fashion and capable of chelating, through H-bonds, metal cyanide anions, neutral 1- and 2-D hybrid networks were generated. Whereas in the presence of M(CN)42− (M = Ni(II), Pd(II) and Pt(II)), 1-D H-bonded networks are formed through a double dihapto mode of H-bonding between the dication and the dianion, in the case of M(CN)64− (M = Fe(II) and Ru(II)), 2-D networks based on the interconnection by the dication 1 of 1-D networks analogous to those formed in the case of [M(CN)4]2− mentioned above are obtained. Interestingly, in the case of [M(CN)6]3− (M = Cr(III)), again a 2-D H-bonded network is formed through the formation of three dihapto modes of H-bonding between the dication and the trianion. Due to this dihapto or chelate mode of H-bonding, a supramolecular chirality of the Δ′ and Λ′ type is generated within the second coordination sphere of the metallic centres. The packing of the achiral 2-D networks thus obtained leads to channels which are occupied by water molecules forming polymeric H-bonded chains.

Synthesis and solid state structural analysis of 1,3-alternate conformer of tetrathiacalix[4]arene tetra-ester, -acid and -ether derivatives

Four new tetrathiacalix[4]arene derivatives blocked in 1,3-alternate conformation and bearing four ester, acid or ether groups were prepared and their 1,3-alternate conformation was established by X-ray diffraction methods on single-crystal.

Molecular tectonics: control of packing of hybrid 1-D and 2-D H-bonded molecular networks formed between bisamidinium dication and cyanometallate anions

Upon combining the dicationic bis-amidinium tecton 2 bearing four propyl chains with tetra- and hexa-cyanometallate anions neutral 1- and 2-D hybrid networks were obtained. In the case of [M(CN)4]2− (M = Ni(II), Pd(II) and Pt(II)), the control of the spacing between consecutive 1-D H-bonded networks by the presence of the propyl chains was demonstrated. For [M(CN)6]3− (M = Fe(III), Co(III), Cr(III)), 2-D networks presenting hexagonal channels have been obtained. In marked contrast with the case based on the use of 1 for which channels are filled with water molecules, in the case of 2, as expected, the solvent molecules were replaced by propyl chains.

Molecular tectonics: generation of 1-D interdigitated and 2-D interwoven helical silver coordination networks by oligoethylene glycol based tectons bearing two benzonitrile moieties

Ligands based on oligoethylene glycol units bearing at their extremities benzonitrile groups behave in the crystalline phase as tectons and lead in the presence of silver cation to different coordination networks. Depending on the number of glycol units, 1-D stair type or 1-D interdigitated and 2-D interwoven architectures composed of helical strands are obtained.

Molecular tectonics: generation of 1- and 2-D copper coordination networks by positional isomeric tectons based on a phenylenediamine backbone bearing two isonicotinoyl moieties

The combination of three isomeric organic tectons 1–3 based on 1,2-, 1,3- and 1,4-phenylenediamine backbones bearing two isonicotinoyl groups with a Cu(OAc)2 neutral complex leads to the formation of 1-D and 2-D coordination networks. Whereas for both tectons 1 and 2 the network is generated through the interconnection of the organic moieties by copper dimers of the paddle-wheel type, in the case of 3, the 2-D network is formed by another type of connector, a binuclear copper complex for which the two metal centres adopt an octahedral coordination geometry.