New N, N′-disubstituted-1,4,5,8-naphthalene tetracarboxylic acid diimides (NTCDI) with fluorinated phenylethyl groups were synthesized. In particular, N,N′-bis(2-(pentafluorophenyl)ethyl)-1,4,5,8naphthalene tetracarboxylic acid diimide (5FPE-NTCDI) showed high electron mobility, more than 0.1 cm 2 /(V s) in air, even though the film was deposited at room temperature. The correlation of the crystallinity, morphology, and mobility with the substrate temperature during deposition (T sub ) was studied using X-ray diffraction (XRD) and atomic force microscopy (AFM). The films of 5FPE-NTCDI exhibited a "thin film phase", mixed phase, and crystal bulk phase as T sub was increased. The mixed phase on an octadecyltrimethoxysilane (OTS)-treated substrate also has high electron mobility due to well connected long fiber-shaped grains. The high mobility at low T sub has enabled fabrication of flexible transistors on the clear plastic substrate poly(ethylene terephthalate) (PET). The highest mobility for a flexible, transparent transistor was 0.23 cm 2 /(V s), obtained with low hysteresis.

A new series of heterocyclic oligomers based on the 1,3,4-oxadiazole ring were synthesized. Other electron-deficient cores (fluorenone and fumaronitrile) were introduced to investigate the oligomers as n-channel materials. The physical properties, thin film morphologies, and field-effect transistor characteristics of the oligomers were evaluated. Thin films were deposited at different substrate temperatures and on variously coated Si/SiO(2) for device optimization. Contrary to our expectations, the thin film devices of 4 revealed p-channel behavior, and the average hole mobility was 0.14 cm(2) V(-1) s(-1) (maximum value 0.18 cm(2) V(-1) s(-1)). Compound 11 is the first example of an oxadiazole-containing organic semiconductor (OSC) oligomer in an n-channel organic field-effect transistor (OFET) and shows moderate mobilities. Non-oxadiazole-containing oligomers 9 and 12 showed n-channel OFET behavior on hexamethyldisilazane-treated and Cytop spin-coated SiO(2) in vacuum. These are the first fluorenone- and fumaronitrile-based n-OSCs demonstrated in transistors. However, oxadiazole-core materials 14 and 16 were inactive in transistor devices.

The triorganotin halides (Cab C,P )SnMe 2 X (2a, X ) Cl; 2b, X ) Br) and a tetraorganotin compound (Cab C,P )SnMe 3 (7), containing the o-carboranylphosphino ligand (Cab C,P ), have been prepared by the reaction of LiCab C,P (1) with Me 2 SnX 2 and Me 3 SnCl, respectively. 1 H, 13 C, 31 P, and 119 Sn NMR spectroscopy indicate that the tin centers in 2a and 2b are pentacoordinate as a result of intramolecular Sn-P coordination, whereas the tin center in 7 is tetracoordinate. The substitution reactions of 2a using NaI, NaN 3 , NaCpFe(CO) 2 , and NaB(CN)H 3 afforded the substituted products (Cab C,P )SnMe 2 X (3, X ) I; 4, X ) N 3 ; 5, X ) CpFe(CO) 2 ; 6, X ) H). The Wurtz-type coupling reaction of 2a with sodium afforded the distannane. The reaction of the distannane 10 with Pd 2 (dba) 3 ‚CHCl 3 afforded the bis(stannyl)palladium complex 11. When compounds 2a and 2b were employed in the reaction with Pd 2 (dba) 3 , the halo-bridged metal complexes 12a and 12b were isolated. The crystal structures of 9b, 11, and 13 were determined by X-ray structural studies. As a result of the Sn-P interaction, the tin atom in 9b exhibits a distorted trigonal-bipyramidal configuration.Supporting Information Available: Tables listing crystallographic information, atomic coordinates and Beq values, anistropic thermal parameters, and intramolecular bond distances, angles, and torsion angles for 9b, 11 and 13. This material is available free of charge via the Internet at http://pubs.acs.org. OM0007872