@article{lysenko_malinovskii_padmaja_wei_diers_bocian_lindsey_2005, title={Multistate molecular information storage using S-acetylthio-derivatized dyads of triple-decker sandwich coordination compounds}, volume={9}, ISSN={["1099-1409"]}, DOI={10.1142/S1088424605000617}, abstractNote={An approach toward molecular information storage employs redox-active molecules attached to an electroactive surface. The chief advantages of such molecular capacitors include higher charge density and more versatile synthetic design than is afforded by typical semiconductor charge-storage materials. An architecture containing two triple-decker sandwich coordination complexes and an S-acetylthiomethyl-terminated tether has been designed for multibit storage. Each triple decker is composed of two phthalocyanines, one porphyrin, and two europium atoms. The oxidation potentials of each triple decker are tuned through the use of different substituents on the phthalocyanines (t-butyl, methyl, H ) and porphyrins (pentyl, p-tolyl). Interleaving of the four cationic oxidation states of each triple decker potentially affords eight distinct oxidation states. Two dyads were examined in solution and in self-assembled monolayers (SAMs) on a Au surface. One dyad exhibited eight distinct states in solution and in the SAM, thus constituting a molecular octal counter. The potentials ranged from −0.1-+1.3 V in solution and +0.1-+1.6 V in the SAM. Taken together, this approach provides a viable means of achieving multibit information storage at relatively low potential.}, number={7}, journal={JOURNAL OF PORPHYRINS AND PHTHALOCYANINES}, author={Lysenko, AB and Malinovskii, VL and Padmaja, K and Wei, LY and Diers, JR and Bocian, DF and Lindsey, JS}, year={2005}, pages={491–508} }
 @article{yasseri_syomin_malinovskii_loewe_lindsey_zaera_bocian_2004, title={Characterization of self-assembled monolayers of porphyrins bearing multiple thiol-derivatized rigid-rod tethers}, volume={126}, ISSN={["0002-7863"]}, DOI={10.1021/ja047723t}, abstractNote={A series of multithiol-functionalized zinc porphyrins has been prepared and characterized as self-assembled monolayers (SAMs) on Au. The molecules, designated ZnPSn (n = 1−4), contain from one to four [(S-acetylthio)methyl]phenylethynylphenyl groups appended to the meso-position of the porphyrin; the other meso-substituents are phenyl groups. For the dithiol-functionalized molecules, both the cis- and the trans-appended structures were examined. The ZnPSn SAMs were investigated using X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and various electrochemical methods. The studies reveal the following characteristics of the ZnPSn SAMs. (1) The ZnPSn molecules bind to the Au surface via a single thiol regardless of the number of thiol appendages that are available per molecular unit. (2) The porphyrins in the ZnPS3 and ZnPS4 SAMs bind to the surface in a more upright orientation than the porphyrins in the ZnPS1, cis-ZnPS2, and trans-ZnPS2 SAMs. The porphyrins in the ZnPS3 and ZnPS4 SAMs are also more densely packed than those in the cis-ZnPS2 and trans-ZnPS2 SAMs. The packing density of the ZnPS3 and ZnPS4 SAMs is similar to that of the ZnPS1 SAMs, despite the larger size of the molecules in the former SAMs. (3) The thermodynamics and kinetics of electron transfer are generally similar for all of the ZnPSn SAMs. The general similarities in the electron-transfer characteristics for all of the SAMs are attributed to the similar binding motif.}, number={38}, journal={JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, author={Yasseri, AA and Syomin, D and Malinovskii, VL and Loewe, RS and Lindsey, JS and Zaera, F and Bocian, DF}, year={2004}, month={Sep}, pages={11944–11953} }
 @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} }
 @article{liu_yasseri_loewe_lysenko_malinovskii_zhao_surthi_li_misra_lindsey_et al._2004, title={Synthesis of porphyrins bearing hydrocarbon tethers and facile covalent attachment to Si(100)}, volume={69}, ISSN={["0022-3263"]}, DOI={10.1021/jo049439q}, abstractNote={The use of redox-active molecules as the active storage elements in memory chips requires the ability to attach the molecules to an electroactive surface in a reliable and robust manner. To explore the use of porphyrins tethered to silicon via carbosilane linkages, 17 porphyrins have been synthesized. Fourteen porphyrins bear a tether at a single meso site, and three porphyrins bear functional groups at two β sites for possible two-point attachment. Two high-temperature processing methods (400 °C under inert atmosphere) have been developed for rapid (minutes), facile covalent attachment to Si platforms. The high-temperature processing conditions afford attachment either by direct deposition of a dilute solution (1 μM−1 mM) of the porphyrin sample onto the Si substrate or sublimation of a neat sample onto the Si substrate. The availability of this diverse collection of porphyrins enables an in-depth examination of the effects of the tether (length, composition, terminal functional group, number of tethers) and steric bulk of nonlinking substituents on the information-storage properties of the porphyrin monolayers obtained upon attachment to silicon. Attachment proceeds readily with a wide variety of hydrocarbon tethers, including 2-(trimethylsilyl)ethynyl, vinyl, allyl, or 3-butenyl directly appended to the porphyrin and iodo, bromomethyl, 2-(trimethylsilyl)ethynyl, ethynyl, vinyl, or allyl appended to the 4-position of a meso-phenyl ring. No attachment occurs with substituents such as phenyl, p-tolyl, mesityl, or ethyl. Collectively, the studies show that the high-temperature attachment procedure (1) has broad scope encompassing diverse functional groups, (2) tolerates a variety of arene substituents, and (3) does not afford indiscriminate attachment. The high-temperature processing conditions are ideally suited for use in fabrication of hybrid molecular/semiconductor circuitry.}, number={17}, journal={JOURNAL OF ORGANIC CHEMISTRY}, author={Liu, ZM and Yasseri, AA and Loewe, RS and Lysenko, AB and Malinovskii, VL and Zhao, Q and Surthi, S and Li, QL and Misra, V and Lindsey, JS and et al.}, year={2004}, month={Aug}, pages={5568–5577} }
 @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 H2Pc = tetra-tert-butylphthalocyanine and H2Por 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 CHCl3 or CH2Cl2. 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 104−105 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} }