@article{balakumar_lysenko_carcel_malinovskii_gryko_schweikart_loewe_yasseri_liu_bocian_et al._2004, title={Diverse redox-active molecules bearing O-, S-, or Se-terminated tethers for attachment to silicon in studies of molecular information storage}, volume={69}, ISSN={["1520-6904"]}, DOI={10.1021/jo034944t}, abstractNote={A molecular approach to information storage employs redox-active molecules tethered to an electroactive surface. Attachment of the molecules to electroactive surfaces requires control over the nature of the tether (linker and surface attachment group). We have synthesized a collection of redox-active molecules bearing different linkers and surface anchor groups in free or protected form (hydroxy, mercapto, S-acetylthio, and Se-acetylseleno) for attachment to surfaces such as silicon, germanium, and gold. The molecules exhibit a number of cationic oxidation states, including one (ferrocene), two [zinc(II)porphyrin], three [cobalt(II)porphyrin], or four (lanthanide triple-decker sandwich compound). Electrochemical studies of monolayers of a variety of the redox-active molecules attached to Si(100) electrodes indicate that molecules exhibit a regular mode of attachment (via a Si-X bond, X = O, S, or Se), relatively homogeneous surface organization, and robust reversible electrochemical behavior. The acetyl protecting group undergoes cleavage during the surface deposition process, enabling attachment to silicon via thio or seleno groups without handling free thiols or selenols.}, number={5}, journal={JOURNAL OF ORGANIC CHEMISTRY}, author={Balakumar, A and Lysenko, AB and Carcel, C and Malinovskii, VL and Gryko, DT and Schweikart, KH and Loewe, RS and Yasseri, AA and Liu, ZM and Bocian, DF and et al.}, year={2004}, month={Mar}, pages={1435–1443} }
 @misc{lindsey_bocian_schweikart_kuhr_2004, title={Multistate triple-decker dyads in three distinct architectures for information storage applications}, volume={6,728,129}, number={2004 Apr. 27}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Lindsey, J. S. and Bocian, D. F. and Schweikart, K. H. and Kuhr, W. G.}, year={2004} }
 @article{carcel_laha_loewe_thamyongkit_schweikart_misra_bocian_lindsey_2004, title={Porphyrin architectures tailored for studies of molecular information storage}, volume={69}, ISSN={["0022-3263"]}, DOI={10.1021/jo0498260}, abstractNote={A molecular approach to information storage employs redox-active molecules tethered to an electroactive surface. Zinc porphyrins tethered to Au(111) or Si(100) provide a benchmark for studies of information storage. Three sets of porphyrins have been synthesized for studies of the interplay of molecular design and charge-storage properties: (1) A set of porphyrins is described for probing the effect of surface attachment atom on electron-transfer kinetics. Each porphyrin bears a meso-CH2X group for surface attachment where X = OH, SAc, or SeAc. (2) A set of porphyrins is described for studying the effect of surface-charge density in monolayers. Each porphyrin bears a benzyl alcohol for surface attachment and three nonlinking meso substituents of a controlled degree of bulkiness. (3) A set of porphyrins is described that enables investigation of on-chip patterning of the electrolyte. Each porphyrin bears a formyl group distal to the surface attachment group for subsequent derivatization with a molecular entity that comprises the electrolyte. Taken together, this collection of molecules enables a variety of studies to elucidate design issues in molecular-based information storage.}, number={20}, journal={JOURNAL OF ORGANIC CHEMISTRY}, author={Carcel, CM and Laha, JK and Loewe, RS and Thamyongkit, P and Schweikart, KH and Misra, V and Bocian, DF and Lindsey, JS}, year={2004}, month={Oct}, pages={6739–6750} }
 @article{roth_yasseri_liu_dabke_malinovskii_schweikart_yu_tiznado_zaera_lindsey_et al._2003, title={Measurements of electron-transfer rates of charge-storage molecular monolayers on Si(100). Toward hybrid molecular/semiconductor information storage devices}, volume={125}, ISSN={["0002-7863"]}, DOI={10.1021/ja021169a}, abstractNote={Redox kinetics were measured for two electroactive molecules attached to Si(100) surfaces, a ferrocene (Fc-BzOH) and a Zn(II) trimesitylporphyrin (Por-BzOH). Each molecule was derivatized with a benzyl alcohol linker for attachment to the Si surface via the formation of a Si-O bond. A complete protocol was developed for the preparation of stable Si(100) surfaces derivatized with the electroactive molecules. The redox-kinetic measurements were performed on the resulting Fc-BzOH and Por-BzOH monolayers to probe (1) the rate of electron transfer (k0) for oxidation in the presence of applied potentials and (2) the rate of charge dissipation after the applied potential is disconnected (in the form of a charge-retention half-life t1/2). The k0 values for the two types of monolayers were found to be similar to one another as were the t1/2 values. Perhaps more importantly, the electron-transfer rates for both the Fc-BzOH and the Por-BzOH monolayers differ from the charge-dissipation rates by approximately 6 orders of magnitude and are strongly dependent on the surface concentration of the electroactive species. For the Por-BzOH monolayers on Si(100), the k0 and t1/2 values and their trends as a function of surface coverage were determined to be similar to those previously measured for the analogous thiol-derivatized molecule assembled on Au(111). In contrast, the Fc-BzOH monolayers on Si(100) were found to exhibit much slower electron-transfer and charge-dissipation rates than those in the corresponding thiol-Au(111) case. Two alternative hypotheses are advanced to explain both the diminution in rates with increased surface coverage and the contrasting behavior with the analogous thiols on Au, one based on space-charge effects at the monolayer-solution interface, and a second relying on changes in distance of the redox centers from the surface as modulated by the orientation of the linking chains. Collectively, the ability to prepare and study stable, electroactive molecular media on Si(100) is likely to be key in the development of hybrid molecular/semiconductor devices.}, number={2}, journal={JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, author={Roth, KM and Yasseri, AA and Liu, ZM and Dabke, RB and Malinovskii, V and Schweikart, KH and Yu, LH and Tiznado, H and Zaera, F and Lindsey, JS and et al.}, year={2003}, month={Jan}, pages={505–517} }
 @article{schweikart_malinovskii_yasseri_li_lysenko_bocian_lindsey_2003, title={Synthesis and characterization of bis(S-acetylthio)-derivatized europium triple-decker monomers and oligomers}, volume={42}, ISSN={["0020-1669"]}, DOI={10.1021/ic034730u}, abstractNote={We report the synthesis of monomers, dimers, trimers, and oligomers of triple-decker (TD) complexes bearing S-acetylthio groups at the termini: AcS-(TD)(n)()-SAc. Each TD was of type (Pc)Eu(Pc)Eu(Por), where H(2)Pc = tetra-tert-butylphthalocyanine and H(2)Por is a meso-tetraarylporphyrin bearing functional groups at the 4-aryl position such as ethynyl, TMS-ethynyl, TIPS-ethynyl, or iodo. The TD arrays were prepared by Sonogashira- and Glaser-type coupling reactions, affording 1,4-diphenylethyne or 1,4-diphenylbutadiyne linkers joining the TDs. Each TD array exhibited high solubility in organic solvents such as CHCl(3) or CH(2)Cl(2). Self-assembled monolayers (SAMs) of all the TDs were prepared on Au substrates and investigated via a variety of electrochemical techniques aimed at determining redox potentials, rates of electron transfer under applied potential, and rates of charge retention in the absence of applied potential. The electrochemical measurements were accompanied by ellipsometric studies aimed at determining SAM thickness and, hence, the orientation of the complexes with respect to the surface plane. All of the TD SAMs exhibit robust, reversible voltammetry yielding four well-resolved waves in the potential range of 0 to +1.6 V (corresponding to the mono-, di-, tri-, and tetracations). The electron-transfer rates for the various oxidation states of all of the TD SAMS are similar and in the 10(4)-10(5) s(-)(1) range. The charge-dissipation rates (measured in terms of a charge-retention half-life) are also similar and are in the 10-60 s range. These rates are influenced by both the packing density of the molecules and the orientation of the molecules on the surface. The full body of data supports the view that all of the dithio-derivatized TD complexes assume a similar geometry on the surface. In particular, the complexes are oriented with their linkers/macrocycle planes generally parallel with the surface, unlike monothio-derivatized analogues, which are in a more perpendicular geometry. The parallel geometry of the dithio-derivatized TDs is qualitatively consistent with covalent attachment to Au via both thiols.}, number={23}, journal={INORGANIC CHEMISTRY}, author={Schweikart, KH and Malinovskii, VL and Yasseri, AA and Li, JZ and Lysenko, AB and Bocian, DF and Lindsey, JS}, year={2003}, month={Nov}, pages={7431–7446} }
 @article{li_mathur_homsi_surthi_misra_malinovskii_schweikart_yu_lindsey_liu_et al._2002, title={Capacitance and conductance characterization of ferrocene-containing self-assembled monolayers on silicon surfaces for memory applications}, volume={81}, ISSN={["0003-6951"]}, DOI={10.1063/1.1500781}, abstractNote={Self-assembled monolayers of 4-ferrocenylbenzyl alcohol attached to silicon provided the basis for electrolyte-molecule-silicon capacitors. Characterization by conventional capacitance and conductance techniques showed very high capacitance and conductance peaks near ∼0.6 V associated with charging and discharging of electrons into and from discrete levels in the monolayer owing to the presence of the redox-active ferrocenes. The reversible charge trapping of these molecules suggest their potential application in memory devices. Due to the molecular scalability and low-power operation, molecular-silicon hybrid devices may be strong candidates for next-generation electronic devices.}, number={8}, journal={APPLIED PHYSICS LETTERS}, author={Li, QL and Mathur, G and Homsi, M and Surthi, S and Misra, V and Malinovskii, V and Schweikart, KH and Yu, LH and Lindsey, JS and Liu, ZM and et al.}, year={2002}, month={Aug}, pages={1494–1496} }