Lanthanide-containing liquid crystals and surfactants

Solvent effects on the photochemical and fluorescence properties of zinc phthalocyanine derivatives

Phthalocyanines and porphyrins are versatile functional pigments with a wide range of applications. These macrocyclic compounds contain four isoindole or pyrrole nitrogen atoms, which can complex with a range of metal ions. Large rare earth metal ions can bring together these tetrapyrrole derivatives to form sandwich-type double- and triple-decker complexes. Depending on the metal centers and the nature of the macrocyclic ligands, these compounds exhibit tunable spectroscopic, electronic, and redox properties, and different extents of intramolecular π−π interactions. Some of the properties of the sandwich-type complexes are unique and enable them to be used as advanced materials for various applications. Over the last two decades, a vast number of homoleptic and heteroleptic double- and triple-decker complexes have been synthesized. With improvements in synthetic procedures, researchers have prepared novel sandwich complexes that could not have been prepared by traditional methods. This Account highlights...

A decade journey in the chemistry of sandwich-type tetrapyrrolato-rare Earth complexes.

The crystal structures of double-decker single molecule magnets (SMM) LnPc(2) (Ln = Tb(III) and Dy(III); Pc = phthalocyanine) and non-SMM YPc(2) were determined by using X-ray diffraction analysis. The compounds are isomorphous to each other. The compounds have metal centers (M = Tb(3+), Dy(3+), and Y(3+)) sandwiched by two Pc ligands via eight isoindole-nitrogen atoms in a square-antiprism fashion. The twist angle between the two Pc ligands is 41.4 degrees. Scanning tunneling microscopy was used to investigate the compounds adsorbed on a Au(111) surface, deposited by using the thermal evaporation in ultrahigh vacuum. Both MPc(2) with eight lobes and MPc with four lobes, which has lost one Pc ligand, were observed. In the scanning tunneling spectroscopy images of TbPc molecules at 4.8 K, a Kondo peak with a Kondo temperature (T(K)) of approximately 250 K was observed near the Fermi level (V = 0 V). On the other hand, DyPc, YPc, and MPc(2) exhibited no Kondo peak. To understand the observed Kondo effect, the energy splitting of sublevels in a crystal field should be taken into consideration. As the next step in our studies on the SMM/Kondo effect in Tb-Pc derivatives, we investigated the electronic transport properties of Ln-Pc molecules as the active layer in top- and bottom-contact thin-film organic field effect transistor devices. Tb-Pc molecule devices exhibit p-type semiconducting properties with a hole mobility (mu(H)) of approximately 10(-4) cm(2) V(-1) s(-1). Interestingly, the Dy-Pc based devices exhibited ambipolar semiconducting properties with an electron mobility (mu(e)) of approximately 10(-5) and a mu(H) of approximately 10(-4) cm(2) V(-1) s(-1). This behavior has important implications for the electronic structure of the molecules.

Direct Observation of Lanthanide(III)-Phthalocyanine Molecules on Au(111) by Using Scanning Tunneling Microscopy and Scanning Tunneling Spectroscopy and Thin-Film Field-Effect Transistor Properties of Tb(III)- and Dy(III)-Phthalocyanine Molecules

Dimers, trimers and oligomers of phthalocyanines and related compounds

Synthesis, spectroscopic and electrochemical properties of substituted bis(phthalocyaninato)lanthanide(III) complexes

Synthesis and spectroscopic properties of octasubstituted (phthalocyaninato)titanium(IV) complexes

Synthetic studies of substituted 2,3-naphthalocyanines

Two series of monoaza-15-crown-5 compounds containing either a fused benzo group or sulfur donor atoms in the macrocycles have been synthesised by 1:1 cyclisation of diols or dithiols with ditosylates in the presence of sodium hydride; the molecular structure of 2,3-benzo-10-N-(4′-methoxyphenyl)-1,4,7,13-tetraoxa-10-azacyclopentadecane (8) has also been determined by single-crystal X-ray analysis.

Roger C. W. Liu

Papers

Synthesis, spectroscopic and electrochemical properties of substituted bis(phthalocyaninato)lanthanide(III) complexes

Synthesis and spectroscopic properties of octasubstituted (phthalocyaninato)titanium(IV) complexes

Synthetic studies of substituted 2,3-naphthalocyanines

Synthesis of mixed aza, oxa and thia crown ethers

Synthesis of Mixed Aza, Oxa, and Thia Crown Ethers.