Designing structural order in electronically active organic solids remains agreat challenge in the field of materials chemistry.Now,2Dpoly(arylene vinylene)s prepared as highly crystalline covalent organic frameworks (COFs) by basecatalyzeda ldol condensation of trimethyltriazine with aromatic dialdehydes are reported. The synthesized polymers are highly emissive (quantum yield of up to 50 %), as commonly observed in their 1D analogues poly(phenylene vinylene)s.The inherent well-defined porosity (surface area ca. 1000 m 2 g À1 , pore diameter ca. 11 for the terephthaldehyde derived COF-1) and 2D structure of these COFs also present an ew set of properties and are likely responsible for the emission color, which is sensitive to the environment. COF-1 is highly hydrophilic and reveals ad ramatic macroscopic structural reorganization that has not been previously observed in framework materials.

We report the first transformation between crystalline vinylene-linked two-dimensional (2D) polymers and crystalline cyclobutane-linked three-dimensional (3D) polymers. Specifically, absorption-edge irradiation of the 2D poly(arylenevinylene) covalent organic frameworks (COFs) results in topological [2+2] cycloaddition cross-linking the π-stacked layers in 3D COFs. The reaction is reversible and heating to 200C leads to a cycloreversion while retaining the COF crystallinity. The resulting difference in connectivity is manifested in the change of mechanical and electronic properties, including exfoliation, blue-shifted UV-Vis absorption, altered luminescence, modified band structure and different acid-doping behavior. The Li-impregnated 2D and 3D COFs show a significant ion conductivity of 1.8×10 −4 S/cm and 3.5×10 −5 S/cm, respectively. Even higher room temperature proton conductivity of 1.7×10 -2 S/cm and 2.2×10 -3 S/cm was found for H2SO4-treated 2D and 3D COFs, respectively.

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The solution polycondensation of 1,4‐bis(hydroxydimethylsilyl)benzene with six bis(dimethylaminosilanes) was carried out by the aminosilane deficient method to give a series of high polymers. The bis(dimethylaminosilanes) were bis(dimethylamino)dimethylsilane, bis(dimethylamino)methylphenylsilane, bis(dimethylamino)diphenylsilane, 1,4‐bis(dimethylaminodimethylsilyl)benzene, 1,3‐bis(dimethylamino)‐1,1,3,3‐tetramethyldisiloxane, and 1,5‐bis(dimethylamino‐1,1,3,3,5,5‐hexamethyltrisiloxane). The condensation of dihydroxymethylphenylsilane with bis‐(dimethylamino)methylphenylsilane to give polymethylphenylsiloxane was also performed. A detailed description of the monomer syntheses and polymerization reactions is provided, since this paper represents the first detailed and systematic description of this polycondensation as an alternative to disilanol or disilanol‐dichlorosilane condensation routes. The thermal properties (i.e., Tg, TGA, DSC) of poly(p‐phenylenetetramethylsiloxane) are compared to those of poly[1,4‐bis(oxydimethylsilyl)benzenel] (where a Si(Me)2O group has been inserted between the silylphenylene units) as well as others in this series, polydimethylsiloxane, and polymethylphenylsiloxane. Similarly, these properties are compared with those of related polymers which include in‐chain ferrocene units. Introduction of Si(Me)2O units into poly(tetramethyl‐p‐silylphenylenesiloxane) systematically decreases Tg and thermal stability. Replacing SiCH3 with SiC6H5 groups increases Tg and thermal stability. Replacing in‐chain C6H4 with ferrocene increases Tg and slightly decreases thermal stability. The values of K and A in the Mark‐Houwink equation were determined for several polymers.

synopsisA new monomer, 1,l'-bis(dimethylaminodimethylsiiyl)ferrocene, was synthesized by two routes and polymerized with three aryl disilanols: dihydroxydiphenylsilane, 1,4bis(hydroxydimethylsilyl)benzene, and 4,4'-bis(hydroxydimet.hylsilyl)biphenyl, yielding three different polysiloxanes. Melt polymerizations carried out a t 1 torr pressure and 100°C resulted in the highest molecular weight polymers. Intramolecular cyclization competed with intermolecular chain extension in polymerization of the bis(aminosilane) with dihydroxydiphenylsilane, resulting in isolation of a bridged derivative, 1,3,5-trisila-2,4-dioxa-l,1,5,5-tetramethyl-3,3-diphenyl[5]ferrocenophane. Cyclization did not compete significantly during the formation of polymers from this bisaminosilane and the two remaining diols, as evidenced by higher yields and greater molecular weights. These polymers could be cast as tough flexible films, and fibers could be drawn from their melts. TGA and DSC data showed the polymer formed from 1,l'-bis(dimethylaminodimethylsilyl)ferrocene and 1,4-bis(hydroxydimethylsily1)benzene to be a t least as thermally stable as an arylene siloxane polymer which differed from the ferrocenylsiloxane structure only in the replacement of the ferrocene moiety with a p-substituted phenylene linkage. The ferrocene-containing polymers were generally hydrolyticdy stable under conditions of refluxing THF-HrO(10: 1) for 1 hr. The polymer-forming reaction was found to follow second-order kinetics, and the specific rate constants for formation of two of the polymers were measured.