This paper describes the preparation of oligo(ethylene glycol)-terminated alkanethiols having structure HS-(CH2)n(0CH2CH2)m0H (m = 3-7) and their use in the formation of self-assembled monolayers (SAMs) on gold. A combination of experimental evidence derived from X-ray photoelectron spectroscopy (XPS), measurement of contact angles, and ellipsometry implies substantial disorder in the oligo(ethylene glycol)-containing segment. The order in the -(CH2)ngroup is not defined by the available evidence. The SAMs are moderately hydrophilic: 0a(H2O) = 34-38°; 0r(H2O) = 22-25°. A study of monolayers containing mixtures of HS(CH2)nCH3 and HS(CH2)u(OCH2CH2)6OH suggests that the oligo(ethylene glycol) moieties are effective at preventing underlying methylene groups from influencing wetting by water. A limited study demonstrates that these oligo(ethylene glycol)-containing SAMs resist the adsorption of protein from solution and suggests that SAMs will be a useful model system for studying the adsorption of proteins onto organic surfaces.

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It is well-known that thermal treatment of aspartic acid produces poly(anhydr0aspartic acid) (polysuccinimide), which can then be hydrolyzed to sodium polyaspartate. Both polysuccinimide and sodium polyaspartate have been analyzed by a variety of one-and two-dimensional NMR techniques. 'H NMR indicates that sodium polyaspartate invariably contains a 3:l ratio of j3:a linkages, under a variety of synthesis and hydrolysis conditions. NMR and lW3C HMBC data show that the sequencing is random. Residual succinimide levels in sodium polyaspartate are detectable down to about 1% by lH NMR. COSY data of polysuccinimide and lW16N HMQC-TOCSY of polysuccinimide synthesized from 100% 15N monomer indicate that phosphoric acid catalysis produces linear polymers, while uncatalyzed materials are branched.

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data, mp, ^, and e for 6 except for 6e were reported previously.11 -(tert-Butylamino)-2,4-dinitronaphthalene (6e): mp 115-115.5 °C; XmaJ 408 nm (e 11600 [MeOH]); NMR (DMSO-d6) 1.33 [s, 9 H, C(CH3)3], 7.97 (br s, 1 , NH, overlapped with 6,7), 8.03 (qui, 2 , H6", partially overlapped with NH), 8.70 (m, 2 , H5,8, overlapped with each other), 9.03 (s, 1 , H3), in which the suffix on hydrogen represents the positional number of a naphthalene moiety.Determination of Products. The typical procedure for determination of the reaction products is described for the reaction of 6d with methylamine. The 10-mL DMSO solution containing 5 mmol (0.137 g) of 6d and 3 equiv of methylamine (40% solution) was stirred for the prescribed time at the prescribed temperature, and then the mixture was poured into 200 mL of water, acidified with the equiv of HC1 based on the methylamine added, extracted with 200 mL of benzene three times, and dried over anhydrous MgS04. After the mixture was filtered, the benzene layer was subjected to HPLC (Shimazu LC-6A, silica gel, hexane-2-propanol (20:1 v/v).