Inorganic/polymer composite films with adjustable small thermal expansion were prepared by incorporating sub-m sized particles of zirconium tungstate (ZrW 2 O 8 ) into aromatic polyimide (PI). ZrW 2 O 8 particles exhibit negative coefficients of thermal expansion (CTE) between 4.8 to 8.7 ppm/K. The cross-sectional SEM images of ZrW 2 O 8 /PI composite films indicate that filler particles are homogeneously dispersed in PI matrix without aggregation. The CTEs of these films are linearly decreased with increasing the volume fraction of ZrW 2 O 8 . The CTE of a composite film containing 60 vol% of filler is as low as that of metallic copper (17 ppm/K). Assuming that the thermal expansion behavior is three-dimensionally isotropic, PI composite films containing more than 50 vol% of ZrW 2 O 8 could achieve coefficients of volumetric thermal expansion smaller than 50 ppm/K. Keyword: Polyimide / thin film / zirconium tungstate / thermal expansion / Organic-inorganic composite

A new photochromic spiro[3H-1,4-oxazine] 4 is described. The absorption spectra of 4 have been examined and compared with those of spiro[indoline-naphthoxazine] 1. The colored form of 4 has the absorption maximum shorter than that of 1. Compound 4 showed excellent light fatigue-resistant property.

(E)-(2-Bromoethenyl)dibromoborane, prepared readily by the bromoboration of acetylene with tribromoborane, can be used as an effective precursor for the stereoselective synthesis of (E)-1,2-disubstituted ethenes.

(E)-(2-Bromoethenyl)diisopropoxyborane is a useful precursor for the synthesis of (E)-olefins by the stepwise cross-coupling reaction with organozinc chlorides and then with organic halides in the presence of a base, both catalyzed by Pd complex.

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