Synergistic microfluidic and electrochemical strategy to activate and pattern surfaces selectively with ligands and cells

We show a straightforward, flexible synergistic approach that combines microfluidics, electrochemistry, and a general immobilization strategy to activate regions of a substrate selectively for the precise immobilization of ligands and cells in patterns for a variety of cell-based assays and cell migration and cell adhesion studies. We develop microfluidic microchips to control the delivery of electrolyte solution to select regions of an electroactive hydroquinone SAM. Once an electrical potential is applied to the substrate, only the hydroquinone exposed to electrolyte solution within the microfluidic channels oxidizes to the corresponding quinone. The quinone form can then react chemoselectively with oxyamine-tethered ligands to pattern the surface. Therefore, this microfluidic/electrochemistry strategy selectively activates the surface for ligand patterning that exactly matches the channel design of the microfluidic channel. We demonstrate the ease of this system by first quantitatively characterizing the electrochemical activation and immobilization of ligands on the surface. Second, we immobilize a fluorescent dye to show the fidelity of the methodology, and third, we show the immobilization of biospecific cell adhesive peptide ligands to pattern cells. This is the first report that combines microfluidics/electrochemistry and a general electroactive immobilization strategy to pattern ligands and cells. We believe that this strategy will be of broad utility for applications ranging from fundamental studies of cell behavior to patterning molecules on a variety of materials for molecular electronic devices.     

The dimeric "hand-shake" motif in complexes and metallo-supramolecular assemblies of cyclotriveratrylene-based ligands

A series of clathrate and metal complexes with cyclotriveratrylene-like molecular host ligands show a similar dimeric homomeric inclusion motif in which a ligand arm of one host is the intra-cavity guest of another and vice versa. This "hand-shake" motif is found in the trinuclear transition metal complex [Cu(3)Cl(6)(1)]CH(3)CN1.5 H(2)O in which 1 is tris(4-[2,2',6',2'-terpyridyl]benzyl)cyclotriguaiacylene; in the self-included M(4)L(4) tetrahedral metallo-supramolecular assembly [Ag(4)(2)(4)] (BF(4))(4) in which 2 is tris-(2-quinolylmethyl)cyclotriguaiacylene; in the 1D coordination chains [Ag(4)]ReO(4) CH(3)CN and [Ag(5)]SbF(6)3 DMFH(2)O in which 4 is tris(1H-imidazol-1-yl)cyclotriguaiacylene and 5 is tris{4-(2-pyridyl)benzyl}cyclotriguaiacylene; and in the acetone clathrate of tris{4-(2-pyridyl)benzyl-amino}cyclotriguaiacylene. Clathrates of ligands 2 and 5 do not show the same dimeric motif, although 2 has an extended homomeric inclusion motif that gives a hexagonal network.     

Ugi products containing boronate esters

The Ugi reaction with formylphenylboronic acid derivatives as the carbonyl component proceeds to give the corresponding boron-containing dipeptide derivatives (Ugi products) in good yields.      

Synthesis, characterization, and reactivity of rhodium(I) acetylacetonato complexes containing pyridinecarboxaldimine ligands

Addition of o-C 6H 4NCHNAr to Rh(coe) 2(acac) (coe = cis-cyclooctene, acac = acetylacetonato) gave several new iminopyridine rhodium(I) complexes of the type Rh(acac)(kappa (2)- o-C 6H 4 NCH NAr) ( 1a Ar = 4-C 6H 4-OMe; 1b Ar = 2,6-C 6H 3-Me 2; 1c Ar = 2,6-C 6H 3-Et 2; 1d Ar = 2,6-C 6H 3- i-Pr 2). All new rhodium complexes have been characterized by a number of physical methods, including multinuclear NMR spectroscopy and X-ray diffraction studies for 1b and 1c. Addition of CHCl 3 to 1a afforded the corresponding rhodium(III) complex trans-Rh(kappa (2)- o-C 6H 4 NCH NAr)(CHCl 2)(Cl)(acac) ( 2). Addition of B 2cat 3 (cat = 1,2-O 2C 6H 4) to 1 gave zwitterionic Rh(eta (6)-catBcat)(kappa (2)- o-C 6H 4 NCH NAr) ( 3). The molecular structure of 3b has been confirmed by a single crystal X-ray diffraction study and shows that the N 2Rh fragment is bound to the catBcat anion via one of the catecholato groups in a eta (6)-fashion. These complexes have also been examined for their ability to catalyze the hydroboration of a series of vinylarenes. Reactions using catecholborane and pinacolborane seem to proceed largely through a dehydrogenative borylation mechanism to give a number of boronated products.     

Synthesis of boron macrocycles from 1,2‐aminoalcohols and 2‐formylphenylboronic acid

Condensation of aminoalcohols with 2‐HC(O)C₆H₄B(OH)₂ afforded the macrocyclic compounds 1–7 with an OBOBO structural unit. Crystals of 1 were triclinic, space group P‐1, a = 9.9818(12) Å, b = 12.8302(15) Å, c = 13.1663(15) Å, α = 105.503(2)°, β = 94.860(2)°, γ = 92.585(2)°, Z = 2.     

Synthesis,characterization, and antimicrobial activities of palladium Schiff base complexes derived from aminosalicylic acids

Six Schiff base compounds have been prepared from the condensation of o-vanillin, 2,3-dihydroxybenzaldehyde and 2,3,4-trihydroxybenzaldehyde with 4-aminosalicylic acid and 5-aminosalicylic acid (5-ASA). Addition of these Schiff bases to [Pd(OAc)₂] afforded the corresponding bis(salicylaldiminato)palladium(II) complexes in moderate to excellent yields. All new palladium complexes have been characterized fully using standard spectroscopic methods, elemental analyses and a single-crystal X-ray diffraction study in the case of 2e, the palladium complex containing Schiff base ligands derived from 5-ASA and 2,3-dihydroxybenzaldehyde. All derivatives of 5-ASA were examined for potential antimicrobial activities against two species of fungi, Aspergillus niger and Saccharomyces cerevisiae, as well as two species of bacteria, Bacillus cereus (Gram-positive) and Pseudomonas aeruginosa (Gram-negative).     

多光子过程中相位退相干时两原子布局数反转

利用全量子理论的方法,研究了存在相位退相干时多光子T-C模型中两个二能级原子与二项式光场相互作用系统中两原子的布居数反转。讨论了相位退相干系数、二项式光场系数、最大光子数、跃迁光子数对原子布居数反转的影响。结果表明：相位退相干减少了原子布居数反转的振幅、破坏了原子的量子特性。改变跃迁光子数,可以改变原子间布居数反转演化周期及演化强度。当二项式光场的最大光子数增大时,原子布居差的崩塌-回复现象就会逐渐消失。相位退相干因子不变时, 二项式光场从相干态过渡到数态过程中,原子布居的振荡频率由大变小,周期性的崩塌与回复现象逐渐消失。     

Co(η(5) -P(5) ){η(2) -P(2) H(mes)}](2-) : A Phospha-Organometallic Complex Obtained by the Transition-Metal-Mediated Activation of the Heptaphosphide Trianion

A carbon copy: The chemical activation of the heptaphosphide trianion with [Co(PEt(2) Ph)(2) (mes)(2) ] (see picture; 1) yields the novel phospha-organometallic complex [Co(η(5) -P(5) ){η(2) -P(2) H(mes)}](2-) (2). The reaction product maintains the nuclearity of the parent cluster, but extensive cage fragmentation takes place to yield a diamagnetic "inorganometallic" cobalt complex.     

The First Principles Investigations of the Thermoelectric Properties of GaN with p- and n-Type Doping

We investigate the thermoelectric properties of GaN with p-and n-type doping by the first principles calculation and the semi-classical Boltzmann theory. We find that the power factors (S2σof p-type GaN (-3500 W/mK2) is about twice that of the n-type (-1750 W/mK2), which indicates the thermoelectric properties of p-type GaN would be better. Thermal conductivity of GaN crystal decreases rapidly as the temperature increases, but it is still too large for thermoelectric applications. The figure of merit (ZT) estimated at 1500 K is 0.134 for p-type GaN crystal and 0.062 for the n-type.     

On the Intermittency in Nuclear Fragmentations

A simple Monte Carlo simulation and even a partition method can be used to reproduce quite well the power law behavior between the factorial moment and the charge interval of fragment charge distributions from the multifragmentation of ¹⁹⁷Au nucleus bombarding emulsion at～1 GeV/nucleon. This indicates that the above power law seems not to be a unique precursor of the intermittent behavior in nuclear multifragmentations.