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Infinite Array (infinite + array)

Distribution by Scientific Domains

Chemistry	80%

Selected Abstracts

Evaluation of the reflected phase of a patch using waveguide simulator for reflectarray design

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 6 2005
N. Lenin
Abstract This paper presents the measured reflected phase-variation curves for microstrip-patch elements of variable size, which form the most essential part in the design of a reflectarray antenna. A waveguide simulator exploiting the concept of infinite array is successfully implemented in the characterization of reflected phase, which avoids the need for large arrays for the empirical design of an element. A set of seven microstrip-array samples, each consisting of three square elements of the same size designed at 10 GHz, is measured. A comparison of the simulations using the finite-element method and the measured results shows good agreement. The phase variation is in the range of +167° to ,178° for a patch-size variation of 5.5 to 13 mm. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 45: 528,531, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20869 [source]

Pseudo-merohedrally twinned praseodymium hexacyanoferrate(III) tetrahydrate

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 11 2004
Vratislav Langer
Crystals of the title compound, diaquahexa-,-cyano-ferrate(III)praseodymium(III) dihydrate, Pr[Fe(CN)6]·4H2O or [PrFe(CN)6(H2O)2]·2H2O, are twinned with three components. The Pr atom is coordinated by eight atoms, viz. six N and two symmetry-related water O atoms. The Pr polyhedron (Pr has site symmetry m2m, Wyckoff position 4c) is linked to an FeC6 octahedron (Fe located on a site with imposed 2/m symmetry, Wyckoff position 4b) through N atoms, forming an infinite array. The second (symmetry independent) water molecule lies on a mirror plane, is not included in coordination and is weakly hydrogen bonded to N atoms. [source]

Polymeric (,2 -nitrato-,2O:O,)(,2 -nitrato-,2O:O)(,4 -pyridinium-4-thiolato-,4S:S:S:S)disilver(I)

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 6 2004
Yu-Biao Chen
The title compound, [Ag2(NO3)2(C5H5NS)]n, was obtained from the reaction of silver nitrate with bis(4-pyridyl) disufide (4-PDS) in a mixture of ethanol and water, which suggests that the disulfide bond of 4-PDS can be cleaved under mild conditions. The structure of the title compound is a two-dimensional infinite array in which the asymmetric unit contains two Ag atoms, a pyridinium-4-thiolate molecule and two nitrate groups. Each pyridinium-4-thiolate molecule acts as a ,4 bridge, linking four Ag atoms, with Ag,S bond distances of 2.4870,(19), 2.5791,(19), 2.5992,(19) and 2.848,(2),Å. The Ag,Ag distances lie in the range 2.889,(2),3.049,(1),Å. [source]

G,G Base-Pairing in Nucleobase Adducts of the Anticancer Drug cis -[PtCl2(NH3)(2-picoline)] and Its trans Isomer

CHEMISTRY - A EUROPEAN JOURNAL, Issue 15 2005
Geraldine McGowan
Abstract cis -[PtCl2(NH3)(2-picoline)] (AMD473) is a sterically-hindered anticancer complex with a profile of chemical and biological activity that differs significantly from that of cisplatin. Adducts of AMD473 with neutral 9-ethylguanine (9-EtGH) and anionic (N1-deprotonated) 9-ethylguanine (9-EtG) as perchlorate and nitrate salts, and also a nitrate salt of the trans isomer (AMD443), were prepared and their structures determined by X-ray crystallography: cis -[Pt(NH3)(2-pic)(9-EtGH)2](ClO4)2 (1),2,H2O,Me2CO, cis -[Pt(NH3)(2-pic)(9-EtGH)2](NO3)2 (2),2,H2O, cis -[Pt(NH3)(2-pic)(9-EtGH)(9-EtG)]NO3 (3),3.5,H2O, trans -[Pt(NH3)(2-pic)(9-EtGH)(9-EtG)]NO3 (4),8,H2O. In all cases, platinum coordination is through N7 of neutral (1, 2) and anionic (3, 4) guanine. In each complex, the guanine bases are arranged in the head-to-tail conformation. In complex 1, there is an infinite array of six-molecule cycles, based on both hydrogen bonding and ,,, stacking of the 2-picoline and guanine rings. Platinum(II) coordinated at N7 acidifies the N1 proton of neutral 9-ethylguanine (pKa=9.57) to give pKa1=8.40 and pKa2=8.75 for complex 2, and pKa1=7.77 and pKa2=9.00 for complex 4. In complexes 3 and 4, three intermolecular hydrogen bonds are formed between neutral and deprotonated guanine ligands involving O6, N1 and N2 sites. Unusually, both of the platinated guanine bases of complexes 3 and 4 participate in this triple GG hydrogen bonding. This is the first report of X-ray crystal structures of nucleobase adducts of the promising anticancer drug AMD473. [source]

Metallophilic interactions in iodido(2,2,:6,,2,,-terpyridine)platinum(II) diiodidoaurate(I)

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 6 2007
Christina S. Angle
In the title compound, [PtI(C15H11N3)][AuI2], the [PtI(terpy)]+ cations (terpy is 2,2,:6,,2,,-terpyridine) stack in pairs about inversion centers through Pt...Pt interactions of 3.5279,(5),Å. The [AuI2], anions also exhibit pairwise stacking, with Au...I distances of 3.7713,(5),Å. The [PtI(terpy)]+ cations and [AuI2], anions aggregate forming infinite arrays of stacked ...({[PtI(terpy)]+...[PtI(terpy)]+}...{[AuI2],...[AuI2],})... units. [source]