Benzo-condensed dithieno[3,2-b:2',3'-d]phospholes have been synthesized that allow convenient tuning of properties that are essential for application as semiconductor materials in organic field-effect transistor (OFET) devices. The versatile reactivity of the trivalent phosphorus atom in these heteropentacenes provides access to a series of materials that show different photophysical properties, significantly different organization in the solid state, and distinctly different electrochemical properties that can be achieved by simple chemical modifications. The materials show strong photoluminescence in solution and in the solid state that depends on the electronic nature of the phosphorus center. Electrochemical studies revealed that the phosphorus atom intrinsically furnishes materials with n-channel or ambipolar behavior, also depending on its electronic nature. The experimental data were verified by DFT quantum chemical calculations and suggest that the phosphorus-based heteropentacenes could be excellent candidates for n-channel OFET semiconductor materials.

A series of dithieno[3,2-b:2',3'-d]phosphole-based transition metal complexes, including Au, Fe, Pt, Rh and W as central metals have been synthesised and characterised. Structural investigations by X-ray single crystal crystallography supported the high degree of pi-conjugation in the dithienophosphole ligands. This essential requirement for potential applications in molecular electronics and optoelectronics provides small band gaps for the materials. Investigations toward the optoelectronic properties of the respective complexes by fluorescence spectroscopy indicated that systematic alterations of the electronic structure are connected to different variables such as transition metal employed, functionalisation of the dithienophosphole ligands as well as complex geometries. The investigated Pt-based complexes exhibit only poor photoluminescence whereas Rh-, W- and Fe-based species with silyl functionalised dithienophosphole ligands show appreciable photophysical properties. The Au complexes investigated exhibit strong photoluminescence properties with very intriguing features in terms of excitation and emission wavelengths, intensity as well as selectivity.

A set of novel phosphine-phosphoramidite ligands possessing two elements of chirality have been prepared through a modular synthetic approach.

A set of chiral monodentate phosphorous triamides (PTA) comprising 1,1′‐binaphthyl‐2,2′‐diamine as the common moiety have been synthesised. Electronic and steric tuning of the ligands was achieved by variation of the substituents at the diamine nitrogen atoms by incorporating methyl, p‐tolyl and tosyl groups. Both chiral and achiral building blocks were used as monoamine components. Notably, (11bR)‐3,5‐dimethyl‐N,N‐bis[(S)‐1‐phenylethyl]‐3,5‐dihydro‐4H‐dinaphtho[2,1‐d:1′,2′‐f][1,3,2]diazaphosphepin‐4‐amine, which is the PTA most closely related to the Feringa phosphoramidite ligand, was synthesised and characterised by NMR spectroscopy and X‐ray diffraction. This PTA displays increased conformational rigidity in comparison with the corresponding phosphoramidite and adopts a C1‐symmetric structure both in the solid state and in solution, even at room temperature. The new PTA ligands were used in the copper‐catalysed conjugate addition of diethylzinc to cyclohex‐2‐enone and the nickel‐catalysed hydrovinylation of styrene giving good activities and chemoselectivities at moderate enantioselectivities in both reactions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Enantioselective syntheses O 0031Highly Efficient and Versatile Phosphine-Phosphoramidite Ligands for Asymmetric Hydrogenation. -The novel ligands possessing two elements of chirality are found to be unique in providing excellent enantioselectivities for hydrogenations of C=C, C=O, and C=N double bonds in combination with three different transitions metals (rhodium, ruthenium, and iridium). -(EGGENSTEIN, M.; THOMAS, A.; THEUERKAUF, J.; FRANCIO*, G.; LEITNER, W.; Adv. Synth. Catal. 351 (2009) 5, 725-732; Inst. Tech. Makromol. Chem.,