VIVALDI—A thermal-neutron laue diffractometer for physics, chemistry and materials science

Wilkinson, C.; Cowan, John A.; Myles, Dean A. A.; Cipriani, F.; McIntyre, G. J.

doi:10.1080/10448630208222874

Cited by 77 publications

(67 citation statements)

References 10 publications

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“…VIVALDI uses the Laue diffraction technique on an unmonochromated thermal-neutron beam and with a large solid-angle (8 sterad) cylindrical image-plate detector, to increase the detected diffracted intensity by oneto-two orders of magnitude compared with a conventional monochromatic experiment. [36] A colorless crystal of 1, with well-developed faces and maximum dimensions 1.7 0.9 0.6 mm 3 , volume~0.5 mm 3 , was selected, wrapped in aluminum foil with some silicon grease, and mounted on a vanadium pin. Seven Laue diffraction patterns were collected at room temperature, at 308 intervals around the vertical axis perpendicular to the incident neutron beam, each exposure lasting 4.5 h. Another seven patterns were collected with a different vertical orientation of the crystal.…”

Section: Methodsmentioning

confidence: 99%

Hydrogen‐Bonded Polyrotaxane‐like Structure Containing Cyclic (H₂O)₄ in [Zn(OAc)₂(μ‐bpe)]⋅2 H₂O: X‐ray and Neutron Diffraction Studies

Deivaraj

Klooster

et al. 2004

Chemistry A European J

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The reaction of 4,4'-bipyridylethane (bpe) and 4,4'-dipyridyl disulfide (dpds) with Zn(OAc)2.2H2O has led to the formation of two coordination polymers, [Zn(OAc)2(mu-bpe)].2H2O (1) and [Zn(OAc)2(mu-dpds)] (2). Both the compounds have zigzag coordination polymeric structures as revealed by X-ray crystallography. However, the presence of two lattice water molecules in 1 results in an interesting difference between the crystal structures. In 1, the carboxylate carbonyl oxygen atoms of the Zn(OAc)2 groups from two different adjacent zigzag polymers and four lattice water molecules form 24-membered hydrogen-bonded rings (graph set notation, R6 (6)(24)). One of the two bpe ligands associated with each Zn(II) center passes through the center of this ring to form a two-dimensional hydrogen-bonded coordination polymeric structure. In the solid state, the adjacent 24-membered hydrogen-bonded rings further fuse together through O-H...O hydrogen bonds among four waters to form cyclic (H2O)4. This results in a one-dimensional hydrogen-bonded ribbon-like polymer comprising fused alternating 24- and eight-membered O-H...O hydrogen-bonded rings. One of the bpe ligands passes through the center of the larger ring to produce an unexpected single self-penetrating three-dimensional hydrogen-bonded network with polyrotaxane-like association. A neutron diffraction study provides a detailed description of the hydrogen bonds involved.

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Section: Methodsmentioning

confidence: 99%

Hydrogen‐Bonded Polyrotaxane‐like Structure Containing Cyclic (H₂O)₄ in [Zn(OAc)₂(μ‐bpe)]⋅2 H₂O: X‐ray and Neutron Diffraction Studies

Deivaraj

Klooster

et al. 2004

Chemistry A European J

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“…Atomic coordinates and displacement parameters are listed in Table 3. A table of (Wilkinson et al, 2002;McIntyre et al, 2006).…”

Section: X-ray and Neutron Crystallographymentioning

confidence: 99%

Hydroxycalciomicrolite, Ca_1.5Ta₂O₆(OH), a new member of the microlite group from Volta Grande pegmatite, Nazareno, Minas Gerais, Brazil

et al. 2017

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Hydroxycalciomicrolite, Ca 1.5 Ta 2 O 6 (OH) is a new microlite-group mineral found in the Volta Grande pegmatite, Nazareno, Minas Gerais, Brazil. It occurs as isolated octahedral and as a combination of octahedral and rhombic dodecahedral crystals, up to 1.5 mm in size. The crystals are yellow and translucent, with a white streak and vitreous to resinous lustre. The mineral is brittle, with a Mohs hardness of 5-6. Cleavage is not observed and fracture is conchoidal. The calculated density is 6.176 g cm -3 . Hydroxycalciomicrolite is isotropic, n calc. = 2.010. The infrared and Raman spectra exhibit bands due to O-H stretching vibrations. The chemical composition determined from electron microprobe analysis (n = 13) is (wt.%): Na 2 O 0.36 (8) Hydroxycalciomicrolite is cubic, with unit-cell parameters a = 10.4205(1) Å, V = 1131.53(2) Å 3 and Z = 8. It represents a pyrochlore supergroup, microlite-group mineral exhibiting P4 3 32 symmetry, instead of Fd 3m. The reduction in symmetry is due to long-range ordering of Ca and vacancies on the A sites. This is the first example of such ordering in a natural pyrochlore, although it is known from synthetic compounds. This result is promising because it suggests that other species with P4 3 32 or lower-symmetry space group can be discovered and characterized.

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“…Die drei breiten Signale im 1 H-NMR-Spektrum sind stark paramagnetisch verschoben und kçnnen den tBu-Substituenten (d = 10.5 ppm) und je einem Satz von Ligand- [20,21] Daher wurden Einkristalle von 1 auch mit Neutronenbeugung strukturell charakterisiert (siehe Hintergrundinformationen, Abbildung S4). [14,22] Die Befunde der [11a] Die Molekülstruktur von 2 im Kristall bestätigt die quadratisch-planare Koordination (Abbildung 2 b). Die bei vierfach koordinierten Iridium(III)-Zentren typischerweise beobachtete Sägebockkonformation [23] kçnnte wegen der sterisch anspruchsvollen tBu-Liganden oder der planaren Konformation des Ligandrückgrats ungünstig sein.…”

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Quadratisch‐planare Iridium(II)‐ und Iridium(III)‐Amidokomplexe mit einem PNP‐Pinzettenliganden

et al. 2011

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Koordinationsverbindungen der Edelmetalle nehmen eine zentrale Stellung in der homogenen Katalyse ein. Die Präfe-renz zur geschlossenschaligen elektronischen Struktur prä-destiniert solche Komplexe zu formalen Zwei-ElektronenRedoxreaktionen (oxidative Addition/reduktive Eliminierung).[1] Die Bedeutung von Ein-Elektronen-Reaktionen der Platinmetalle, z. B. bei radikalischen H 2 -, C-H-und C-C-Aktivierungen oder bei katalytischen Oxidationen, wurde bereits demonstriert, [2][3][4][5] dennoch sind voll charakterisierte Metalloradikale noch immer selten.[ [8]Ebenso sind Platinmetallkomplexe mit gerader Valenzelektronenzahl und elektronischer High-Spin-Konfiguration wegen der generell hçheren Ligandenfeldaufspaltung der 4d/ 5d-Metallionen als bei 3d-Metallen sehr selten. Eine Ausnahme bilden quadratisch-planare d 6 -Disilylamidokomplexe vom Typ [MX (L 5 )] (M = Ru, Os; X = F, Cl, I, Trifluormethansulfonat (OTf); L 5 = N(SiMe 2 CH 2 PtBu 2 ) 2 ), die in Analogie zu Eisen(II) eine elektronische Intermediate-SpinKonfiguration aufweisen. [9,10] [Ir(H)Cl(C 8 H 13 )(HL 1 )] (3; R = tBu) [13] wird in situ mit Benzochinon (2.5 ¾quiv.) zum türkisfarbenen 1 in Ausbeuten an isoliertem Produkt von bis zu 60 % oxidiert (Schema 2). [14] Im 31 P-NMR-Spektrum von 1 werden keine Signale beobachtet. Die drei breiten Signale im 1 H-NMR-Spektrum sind stark paramagnetisch verschoben und kçnnen den tBu-Substituenten (d = 10.5 ppm) und je einem Satz von Ligand-

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VIVALDI—A thermal-neutron laue diffractometer for physics, chemistry and materials science

Cited by 77 publications

References 10 publications

Hydrogen‐Bonded Polyrotaxane‐like Structure Containing Cyclic (H₂O)₄ in [Zn(OAc)₂(μ‐bpe)]⋅2 H₂O: X‐ray and Neutron Diffraction Studies

Hydrogen‐Bonded Polyrotaxane‐like Structure Containing Cyclic (H₂O)₄ in [Zn(OAc)₂(μ‐bpe)]⋅2 H₂O: X‐ray and Neutron Diffraction Studies

Hydroxycalciomicrolite, Ca_1.5Ta₂O₆(OH), a new member of the microlite group from Volta Grande pegmatite, Nazareno, Minas Gerais, Brazil

Quadratisch‐planare Iridium(II)‐ und Iridium(III)‐Amidokomplexe mit einem PNP‐Pinzettenliganden

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VIVALDI—A thermal-neutron laue diffractometer for physics, chemistry and materials science

Cited by 77 publications

References 10 publications

Hydrogen‐Bonded Polyrotaxane‐like Structure Containing Cyclic (H2O)4 in [Zn(OAc)2(μ‐bpe)]⋅2 H2O: X‐ray and Neutron Diffraction Studies

Hydrogen‐Bonded Polyrotaxane‐like Structure Containing Cyclic (H2O)4 in [Zn(OAc)2(μ‐bpe)]⋅2 H2O: X‐ray and Neutron Diffraction Studies

Hydroxycalciomicrolite, Ca1.5Ta2O6(OH), a new member of the microlite group from Volta Grande pegmatite, Nazareno, Minas Gerais, Brazil

Quadratisch‐planare Iridium(II)‐ und Iridium(III)‐Amidokomplexe mit einem PNP‐Pinzettenliganden

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Hydrogen‐Bonded Polyrotaxane‐like Structure Containing Cyclic (H₂O)₄ in [Zn(OAc)₂(μ‐bpe)]⋅2 H₂O: X‐ray and Neutron Diffraction Studies

Hydrogen‐Bonded Polyrotaxane‐like Structure Containing Cyclic (H₂O)₄ in [Zn(OAc)₂(μ‐bpe)]⋅2 H₂O: X‐ray and Neutron Diffraction Studies

Hydroxycalciomicrolite, Ca_1.5Ta₂O₆(OH), a new member of the microlite group from Volta Grande pegmatite, Nazareno, Minas Gerais, Brazil