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71.
David S. Maxwell Duoli SunZhenghong Peng Diana V. MartinBasvoju A. Bhanu Prasad William G. Bornmann 《Tetrahedron letters》2013
We report the synthesis of a macrocycle utilizing a novel framework of standard amino acids in combination with subunits that we have named as Linked Amino Acid Mimetics (LAAMs). Macrocycles based on the LAAM concept provide both a peptide targeting region and two independently variable functional regions. In the prototype structure, the commonly known Arg-Gly-Asp (RGD) sequence was used for the targeting region. The functional regions contain a phenyl group, and the linkage was formed via a Ring-Closing Metathesis (RCM) reaction. 相似文献
72.
Multiscale Approach to the Study of the Electronic Properties of Two Thiophene Curcuminoid Molecules 下载免费PDF全文
Alvaro Etcheverry‐Berríos Ignacio Olavarría Dr. Mickael L. Perrin Raúl Díaz‐Torres Domingo Jullian Dr. Ingrid Ponce Dr. José H. Zagal Dr. Jorge Pavez Dr. Sergio O. Vásquez Dr. Herre S. J. van der Zant Dr. Diana Dulić Dr. Núria Aliaga‐Alcalde Dr. Monica Soler 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(36):12808-12818
We studied the electronic and conductance properties of two thiophene–curcuminoid molecules, 2‐thphCCM ( 1 ) and 3‐thphCCM ( 2 ), in which the only structural difference is the position of the sulfur atoms in the thiophene terminal groups. We used electrochemical techniques as well as UV/Vis absorption studies to obtain the values of the HOMO–LUMO band gap energies, showing that molecule 1 has lower values than 2 . Theoretical calculations show the same trend. Self‐assembled monolayers (SAMs) of these molecules were studied by using electrochemistry, showing that the interaction with gold reduces drastically the HOMO–LUMO gap in both molecules to almost the same value. Single‐molecule conductance measurements show that molecule 2 has two different conductance values, whereas molecule 1 exhibits only one. Based on theoretical calculations, we conclude that the lowest conductance value, similar in both molecules, corresponds to a van der Waals interaction between the thiophene ring and the electrodes. The one order of magnitude higher conductance value for molecule 2 corresponds to a coordinate (dative covalent) interaction between the sulfur atoms and the gold electrodes. 相似文献
73.
Maja Ponikvar-Svet Diana N. Zeiger Loryn R. Keating Joel F. Liebman 《Structural chemistry》2012,23(6):2019-2037
In the current review of the journal Structural Chemistry, the contents of the issues 1–3 for the calendar year 2012 are related to thermochemistry. A brief thermochemical commentary is added to the summary of each article. 相似文献
74.
Deepti A. Salvi Giovanna M. Aita Diana Robert Victor Bazan 《Applied biochemistry and biotechnology》2010,161(1-8):67-74
A new pretreatment technology using dilute ammonium hydroxide was evaluated for ethanol production on sorghum. Sorghum fibers, ammonia, and water at a ratio of 1:0.14:8 were heated to 160 °C and held for 1 h under 140–160 psi pressure. Approximately, 44% lignin and 35% hemicellulose were removed during the process. Hydrolysis of untreated and dilute ammonia pretreated fibers was carried out at 10% dry solids at an enzyme concentration of 60 FPU Spezyme CP and 64 CBU Novozyme 188/g glucan. Cellulose digestibility was higher (84%) for ammonia pretreated sorghum as compared to untreated sorghum (38%). Fermentations with Saccharomyces cerevisiae D5A resulted in 24 g ethanol /100 g dry biomass for dilute ammonia pretreated sorghum and 9 g ethanol /100 g dry biomass for untreated sorghum. 相似文献
75.
[reaction: see text] Data are presented indicating that the potent antitumor activity of 2-crotonyloxymethyl-(4R,5R,6R)-4,5,6-trihydroxy-2-cyclohexenone (COTC) and 2-crotonyloxymethyl-2-cyclohexenone (COMC) is not likely the result of glyoxalase I inhibition, as has long been assumed. An alternative hypothesis is presented, based on the finding that COMC is a substrate for human glutathionyl transferase, which produces a transient, highly electrophilic glutathionylated 2-exomethylenecyclohexanone that can covalently modify proteins and nucleic acids. 相似文献
76.
77.
Bifunctional, conjugated oligomers for orthogonal self-assembly: selectivity varies from planar substrates to nanoparticles 总被引:1,自引:0,他引:1
Walker BR Wassel RA Stefanescu DM Gorman CB 《Journal of the American Chemical Society》2004,126(50):16330-16331
A diphenylacetylene containing two different end groups (isonitrile and thioacetate) was synthesized, showing that the chemistry used to install each end group is compatible with that of the others. The isonitrile group binds preferentially to platinum, and the thiol group binds preferentially to gold. However, the selectivity was different when nanoparticles were compared to planar substrates. 相似文献
78.
Kettle SF Boccaleri E Diana E Rossetti R Stanghellini PL Iapalucci MC Longoni G 《Inorganic chemistry》2003,42(20):6314-6322
The nu(CO) vibrational spectra of planar transition cluster carbonyls containing M(CO)(4) groups are studied. It is possible to anticipate qualitatively, both for the infrared and Raman, the band intensity changes associated with increasing metallic nature of the cluster. These enable a unification of the band patterns shown by the species reported. As for (idealized) spherical clusters, the spherical harmonic model (SHM), suitably modified, becomes of more general applicability as cluster size increases, although for smaller species the tensor harmonic model (THM) makes a contribution. 相似文献
79.
The dinuclear copper(I) complex [Cu(2)L(1)(CH(3)CN)(2)](ClO(4))(2) (1, L(1) = 3,6,9,17,20,23-hexaazatricyclo[23.3.1.1]triaconta-1(29),2,9,11(30),12(13),14,16,23,25,27-decaene) has been structurally characterized. As previously described, intramolecular ligand hydroxylation (at the aromatic ring) was observed when 1 was reacted with dioxygen. A stopped-flow analysis of the reaction of 1 with dioxygen under different conditions did not allow a "dioxygen intermediate" to be spectroscopically detected. Detailed NMR and electrochemical data on 1 are also presented and evaluated for the first time. No copper(II) complexes of L(1) could be characterized due to hydrolysis of the compounds. In contrast, complex 2-differing from 1 only in an increase in the size of the chelate rings-did not undergo intramolecular hydroxylation when it was oxidized. The crystal structure of 2 is also described. 相似文献
80.
S. F. A. Kettle E. Boccaleri E. Diana R. Rossetti P. L. Stanghellini M. C. Iapalucci G. Longoni 《Journal of Cluster Science》2001,12(1):175-186
When the Fe(CO)4 and M(CO)5 (M=Cr, W) groups are co-ordinated in C3v and C4v fashion, respectively, in transition metal carbonyl cluster species they contain two sets of non-symmetry related carbonyl groups. In the application of the spherical harmonic model (SHM) to the interpretation of the infrared spectra of these compounds it proves necessary first to treat these as for a normal, isolated, M(CO)4 or M(CO)5 group and then apply the SHM. This recognition gives insights into the general application of the SHM. 相似文献