Structural studies of technetium complexes. V. The preparation and crystal structure of Dichlorobis(diethyldithiocarbamato)thionitrosyltechnetium(III)

1984 ◽  
Vol 37 (4) ◽  
pp. 751 ◽  
Author(s):  
J Baldas ◽  
J Bonnyman ◽  
MF Mackay ◽  
GA Williams

Dichlorobis(diethyldithiocarbamato)thionitrosyltechnetium(III), [Tc(S2CNEt2)2Cl2(NS)], has been prepared by the reaction of [Tc(S2CNEt2)2N] with either disulfur dichloride or thionyl chloride. The crystal structure of [TC(S2CNEt2)2Cl2(NS)] has been determined by single-crystal X-ray diffraction methods at 15�C. Crystals are orthorhombic, space group Pcmn, with a 8.936(1), b 15.681(1), c 28.445(7) �, and Z 8. Automatic diffractometry has provided significant Bragg intensities for 2078 independent reflections, and the structure has been refined by full-matrix least-squares methods to R 0.078. The crystal lattice is disordered across a non-crystallographic mirror plane, the degree of disorder being 4.0(2)% for the crystal described above, and 21.9(7)% for another crystal initially used to obtain an intensity data set. There are two independent molecules of [Tc(S2CNEt2)2Cl2(NS)] in the asymmetric unit, and in each the technetium atom is seven-coordinate with a pentagonal-bipyramidal coordination environment. The Tc=N=S bonding is linear with Tc=N c. 1.75 and N=S c. 1.52 �, which indicates that the thionitrosyl group is a three-electron donor with a formal positive charge. This is only the third crystal structure of a complex containing the thionitrosyl group to be determined, and the first for technetium.

Author(s):  
Dongmin Lee ◽  
Hyeri Bu ◽  
Dohwan Kim ◽  
Jooeun Hyoung ◽  
Seung-Tae Hong

The crystal structure of calcium perchlorate anhydrate was determined from laboratory X-ray powder diffraction data. The title compound was obtained by heating hydrated calcium perchlorate [Ca(ClO4)2·xH2O] at 623 K in air for 12 h. It crystallizes in the orthorhombic space group Pbca and is isotypic with Ca(AlD4)2. The asymmetric unit contains one Ca, two Cl and eight O sites, all on general sites (Wyckoff position 8c). The crystal structure consists of isolated ClO4 − tetrahedra and Ca2+ cations. The Ca2+ cation is coordinated by eight O atoms of eight symmetry-related ClO4 − tetrahedra within a distorted square-antiprismatic environment.


2006 ◽  
Vol 62 (5) ◽  
pp. 919-925 ◽  
Author(s):  
Małgorzata Hołyńska ◽  
Iwona Bryndal ◽  
Tadeusz Lis

The X-ray diffraction pattern obtained for a crystal of triammonium bis(O-phospho-L-serinate) trihydrate at 100 K displays the presence of weak superstructure reflections with odd l indices. Omission of the superstructure reflections leads to orthorhombic Laue symmetry. The structure may be solved and refined in the space group P212121 as an average structure omitting the weak reflections. The model reveals the presence of O-phospho-L-serinate monoanions, ammonium cations and partly disordered water molecules. The structure solution for the whole data set could be obtained only in the space group P21. There are two monoanions and two dianions of O-phospho-L-serinate per asymmetric unit, as well as six ordered ammonium cations and six water molecules.


2013 ◽  
Vol 70 (1) ◽  
pp. 2-6 ◽  
Author(s):  
Julien P. A. Makongo ◽  
Svilen Bobev

The series ofRE5Li2Sn7(RE= Ce–Sm) compounds were synthesized by high-temperature reactions and structurally characterized by single-crystal X-ray diffraction. The compounds are pentacerium dilithium heptastannide, Ce5Li1.97Sn7.03, pentapreseodymium dilithium heptastannide, Pr5Li1.98Sn7.02, pentaneodymium dilithium heptastannide, Nd5Li1.99Sn7.01, and pentasamarium dilithium heptastannide, Sm5Li2Sn7. All five compounds crystallize in the chiral orthorhombic space groupP212121(No. 19), which is relatively uncommon among intermetallic phases. The structure belongs to the Ce5Li2Sn7structure type (Pearson symboloP56), with 14 unique atoms in the asymmetric unit. Minor compositional variations exist, due to the mixed occupancy of Li and Sn atoms at one of the Li sites. The small occupational disorder is most evident forRE5Li2−xSn7+x(RE= Ce, Pr;x≃ 0.03), while the structure of Nd5Li2Sn7and Sm5Li2Sn7show no apparent disorder.


1992 ◽  
Vol 45 (6) ◽  
pp. 1021 ◽  
Author(s):  
MP Hegarty ◽  
CHL Kennard ◽  
KA Byriel ◽  
G Smith

The crystal structure of the hepatotoxic amino acid indospicine [L-6-amidino-2-aminohexanoic acid, (S)-2,7-diamino-7-iminoheptanoic acid], as its hydrochloride hydrate, has been determined by X-ray diffraction and refined to a residual R 0.036 for 845 observed reflections collected at 173 K. Crystals are orthorhombic, space group P 22121 with 8 molecules in a cell of dimensions a 5.1541(4), b 14.083(1), c 31.781(3) � . The structure is consistent with the one previously derived from chemical data but with the presence of a terminal amidinium ion and an α-amino acid zwitterion pair. The two independent molecules in the asymmetric unit are conformationally different and form a head-to-tail packing motif linked by NH(amidino)…O(carboxyl) hydrogenbonds (N…O,2.80, 2.85 � ). The structure also features extensive hydrogen bonding involving the water of solvation.


Author(s):  
Jooeun Hyoung ◽  
Hyeon Woo Lee ◽  
So Jin Kim ◽  
Hong Rim Shin ◽  
Seung-Tae Hong

The crystal structure of strontium perchlorate anhydrate, Sr(ClO4)2, was determined and refined from laboratory powder X-ray diffraction data. The material was obtained by dehydration of Sr(ClO4)2·3H2O at 523 K for two weeks. It crystallizes in the orthorhombic space group Pbca and is isotypic with Ca(AlD4)2 and Ca(ClO4)2. The asymmetric unit contains one Sr, two Cl and eight O sites, all on general positions (Wyckoff position 8c). The crystal structure consists of Sr2+ cations and isolated ClO4 − tetrahedra. The Sr2+ cation is coordinated by eight O atoms from eight ClO4 − tetrahedra. The validity of the crystal structure model for Sr(ClO4)2 anhydrate was confirmed by the bond valence method.


1982 ◽  
Vol 35 (12) ◽  
pp. 2413 ◽  
Author(s):  
J Baldas ◽  
J Boas ◽  
J Bonnyman ◽  
MF Mackay ◽  
GA Williams

Tris[2-aminobenzenethiolato(2–)-S,N]technetium(VI), Tc(NHC6H4S)3, has been prepared by the reaction of ammonium pertechnetate with 2-aminobenzenethiol in 0.1 M hydrochloric acid solution at room temperature. The crystal structure of Tc(NHC6H4S)3 has been determined by single-crystal X-ray diffraction methods at 17�C. Crystals are orthorhombic, space group P212121, with a 10.696(2), b 11.363(1), c l5.220(2) �, and Z 4. Automatic diffractometry has provided significant Bragg intensities for 1413 independent reflections, and the structure of the correct enantiomorph has been refined by full-matrix least-squares methods to R 0.044. The compound, which is isostructural with the molybdenum analogue, consists of discrete molecules of Tc(NHC6H4S)3. The environment about the technetium atom closely approximates a trigonal-prismatic geometry. This is the first example where this geometry has been established with technetium. Differences in detail between the structures of TC(NHC6H4S)3 and its molybdenum analogue are discussed. In particular the S3N3 coordination polyhedron in TC(NHC6H4S)3is contracted and the distortions from ideal trigonal-prismatic geometry are less than in the molybdenum analogue.


2017 ◽  
Vol 72 (12) ◽  
pp. 983-988 ◽  
Author(s):  
Martin K. Schmitt ◽  
Hubert Huppertz

Abstractβ-Y(BO2)3 was synthesized in a Walker-type multianvil module at 5.9 GPa/1000°C. The crystal structure has been elucidated through single-crystal X-ray diffraction. β-Y(BO2)3 crystallizes in the orthorhombic space group Pnma (no. 62) with the lattice parameters a=15.886(2), b=7.3860(6), and c=12.2119(9) Å. Its crystal structure will be discussed in the context of the isotypic lanthanide borates β-Ln(BO2)3 (Ln=Nd, Sm, Gd–Lu).


2008 ◽  
Vol 63 (12) ◽  
pp. 1402-1406
Author(s):  
Monika Simon ◽  
Carol Csunderlik ◽  
G. Jones

N-Alkyl-o-nitrophenylcarbamates as solids present two carbonyl stretching bands in the region 1700 - 1800 cm−1 but similar N-alkyl-p-nitrophenylcarbamates have only one such band in the IR spectrum. In solution both kinds of carbamate present one carbonyl stretching band, but for the former, the splittings occur when the carbamates crystallize. Four crystal structures were analyzed by X-ray diffraction. The two ortho derivatives have more than one molecule in the asymmetric unit, which is consistent with the IR observations.


1979 ◽  
Vol 57 (1) ◽  
pp. 57-61 ◽  
Author(s):  
R. Melanson ◽  
F. D. Rochon

The crystal structure of [Pt(diethylenetriamine)(guanosine)](ClO4)2 has been determined by X-ray diffraction. The crystals are orthorhombic, space group P212121, with a = 12.486(6), b = 13.444(7), c = 14.678(11) Å, and Z = 4. The structure was refined by block-diagonal least-squares analysis to a conventional R factor of 0.050 and a weighted Rw = 0.045.The coordination around the platinum atom is square planar. Guanosine is bonded to platinum through N(7). The purine planar ring makes an angle of 62.7° with the platinum coordination plane. The structure is stabilized by hydrogen bonding.


2014 ◽  
Vol 70 (a1) ◽  
pp. C1138-C1138
Author(s):  
Chiaki Tsuboi ◽  
Kazuki Aburaya ◽  
Shingo Higuchi ◽  
Fumiko Kimura ◽  
Masataka Maeyama ◽  
...  

We have developed magnetically oriented microcrystal array (MOMA) technique that enables single crystal X-ray diffraction analyses from microcrystalline powder. In this method, microcrystals suspended in a UV-curable monomer matrix are there-dimensionally aligned by special rotating magnetic field, followed by consolidation of the matrix by photopolymerization. From thus achieved MOMAs, we have been succeeded in crystal structure analysis for some substances [1, 2]. Though MOMA method is an effective technique, it has some problems as follows: in a MOMA, the alignment is deteriorated during the consolidation process. In addition, the sample microcrystals cannot be recovered from a MOMA. To overcome these problems, we performed an in-situ X-ray diffraction measurement using a three-dimensional magnetically oriented microcrystal suspension (3D MOMS) of L-alanine. An experimental setting of the in-situ X-ray measurement of MOMS is schematically shown in the figure. L-alanine microcrystal suspension was poured into a glass capillary and placed on the rotating unit equipped with a pair of neodymium magnets. Rotating X-ray chopper with 10°-slits was placed between the collimator and the suspension. By using this chopper, it was possible to expose the X-ray only when the rotating MOMS makes a specific direction with respect to the impinging X-ray. This has the same effect as the omega oscillation in conventional single crystal measurement. A total of 22 XRD images of 10° increments from 0° to 220° were obtained. The data set was processed by using conventional software to obtain three-dimensional molecular structure of L-alanine. The structure is in good agreement with that reported for the single crystal. R1 and wR2 were 6.53 and 17.4 %, respectively. RMSD value between the determined molecular structure and the reported one was 0.0045 Å. From this result, we conclude that this method can be effective and practical to be used widely for crystal structure analyses.


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