Complexes of Tris(N-piperidinomethyl)phosphine Oxide with Zinc and Cadmium

1996 ◽  
Vol 61 (9) ◽  
pp. 1321-1334 ◽  
Author(s):  
Pavel Vojtíšek ◽  
Ivana Císařová
Keyword(s):  
Coordination Sphere ◽  
Phosphine Oxide ◽  
Chelate Ring ◽  
The Other ◽  
X Ray Diffraction ◽  
X Ray ◽  
Membered Chelate Ring ◽  
Other Hand ◽  
Ring Structures ◽  
The Way

A number of compounds which can by their stoichiometry be classified into several groups have been prepared by reaction of tris(N-piperidinomethyl)phosphine oxide (tppo) with Zn(II) and Cd(II) salts. The structure of two Zn(II) complexes differing by their Zn : tppo ratio and of one Cd(II) complex has been determined by the X-ray diffraction technique. The results show that in all the cases tppo is bound as divalent chelate N,O-donor, but the geometry of coordination sphere of M(II) decisively affects the steric arrangement of the five-membered chelate ring. Structures of the compounds studied are entirely different from those of Zn(II) complexes of sterically less demanding P,P-dimethyl-P-aminomethylphosphine oxide (dmao). On the other hand, the way of coordination of tppo is the same as that found in the case of the Co(II) complex of tris(N,N-dimethylaminomethyl)phosphine oxide.

Induction of Λ-helicity in a zinc complex with an alanine-appended aminopyridine ligand

2021 ◽  
Vol 77 (8) ◽  
Author(s):  
Berislav Perić ◽  
Zoran Kokan ◽  
Srećko I. Kirin
Keyword(s):  
Zinc Complex ◽  
Chelate Ring ◽  
Ionic Interactions ◽  
Stacking Interactions ◽  
Neutral Ligand ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Third ◽  
Membered Chelate Ring ◽  
The Stability

The crystal structure of tris[dimethyl 5-({1-[(pyridin-2-yl-κN)carbamoyl-κO]ethyl}carbamoyl)benzene-1,3-dicarboxylate]zinc(II) dinitrate acetonitrile trisolvate, [Zn(C19H19N3O6)3](NO3)2·3CH3CN or [Zn(L)3](NO3)2·3CH3CN, (1), has been determined by single-crystal X-ray diffraction. The neutral ligand L coordinates to the Zn2+ cation in a bidentate fashion via the pyridine N atom and an amide O atom, forming a six-membered chelate ring. The Λ-helical chirality of the Zn2+ coordination sphere is induced by pendant L-alanine residues through stacking interactions between the arene groups of two coordinated ligands, assisted by a hydrogen bond between amide groups bonded to the stacked arene rings. The third ligand is coordinated to the Zn2+ cation by the same six-membered chelate ring, but in the opposite direction with respect to the analogous chelate rings of the first two coordinated ligands. Besides ionic interactions between [ZnL 3]2+ complexes and NO3 − anions, several types of hydrogen bonds and intermolecular stacking interactions contribute to the stability of the solid-state phase.

Trifluoromethylaryl-Substituted Quinoxalines: Unusual Ruthenium- Amidininate Complexes and their Suitability for Anellation Reactions

2005 ◽  
Vol 60 (8) ◽  
pp. 843-852 ◽  
Author(s):  
Frank Schramm ◽  
Dirk Walther ◽  
Helmar Görls ◽  
Christian Käpplinger ◽  
Rainer Beckert
Keyword(s):  
Boron Trifluoride ◽  
Chelate Ring ◽  
Ruthenium Complex ◽  
Structural Motif ◽  
X Ray Diffraction ◽  
Quinoxaline Derivative ◽  
Imidazolium Salt ◽  
X Ray ◽  
Membered Chelate Ring ◽  
Complex Fragment

The reaction of the 2,3-dianilino-quinoxaline 1 with an equivalent of triethyl orthoformiate results in a cyclic aminalester 2. An excess of triethyl orthoformate results in the carbene dimer 4. With the help of boron trifluoride, 2 can be transformed into the imidazolium salt 3. Reaction of 1 with KOtC4H9 leads to a quinoxaline derivative 5 under anellation of a benzene ring whereas the related pyrazino-quinoxaline 6 (formed from tetraaminobenzene tetrahydrochloride and bis-(3- trifluoromethylphenyl) oxalimidoyl chloride) does not react under similar conditions. However, 6 can be activated towards anellation by employing the complex fragment [(tbbpy)2Ru]2+, tbbpy: bis(4,4’-di-tert-butyl-2,2’-bipyridine). This generates an unusual ruthenium complex 9 which could be characterised by X-ray diffraction. Complex 9 contains a pentacene derivative and coordinates the ruthenium fragment at the amidinate moiety thus forming a four-membered chelate ring. Isolation of a second ruthenium complex 8 which contains an intact pyrazino-quinoxaline 6 in which the metal is also coordinated to an amidinato group supports the assumption that the anellation reaction occurs only after metal complexation at the amidinate group. In contrast to this, the smaller [(tmeda)2Pd]2+ fragment reacts with the pyrazino-quinoxaline 6 to form the mononuclear Pd complex 10. Its structural motif (X-ray diffraction) shows that the palladium centre coordinates at the 1,4-diamino group of the intact pyrazino-quinoxaline to form a five-membered chelate ring. This suggests that the bulkiness of the complex fragment determines whether or not an anellation reaction can take place.

X-Ray Diffraction of Iron Containing Samples: The Importance of a Suitable Configuration

2017 ◽  
Vol 262 ◽  
pp. 545-548 ◽  
Author(s):  
Yvonne M. Mos ◽  
Arnold C. Vermeulen ◽  
Cees N.J. Buisman ◽  
Jan Weijma
Keyword(s):  
Radiation Source ◽  
The Other ◽  
Phase Identification ◽  
X Ray Diffraction ◽  
High Quality ◽  
Crystalline Phases ◽  
X Ray ◽  
Other Hand ◽  
Cobalt Radiation

X-ray diffraction (XRD) is a commonly used technology to identify crystalline phases. However, care must be taken with the combination of XRD configuration and sample. Copper (most commonly used radiation source) is a poor match with iron containing materials due to induced fluorescence. Magnetite and maghemite are analysed in different configurations using copper or cobalt radiation. Results show the effects of fluorescence repressing measures and the superiority of diffractograms obtained with cobalt radiation. Diffractograms obtained with copper radiation make incontestable phase identification often impossible. Cobalt radiation on the other hand yields high quality diffractograms, making phase identification straightforward.

Metallographic, Structural and Mechanical Characterization of a Low Density Fe-Mn-Al-C Steel Microalloyed with Ti/B in As-Cast and Homogenized Conditions

MRS Advances ◽  
2018 ◽  
Vol 3 (64) ◽  
pp. 3971-3978 ◽  
Author(s):  
O.E. Villanueva-Perez ◽  
I. Mejía ◽  
V. García-García ◽  
A. Bedolla-Jacuinde
Keyword(s):  
Grain Size ◽  
Mechanical Characterization ◽  
The Other ◽  
Low Density ◽  
X Ray Diffraction ◽  
X Ray ◽  
Other Hand ◽  
Average Grain Size ◽  
Cast Condition

ABSTRACTLow density (LD) steels have shown particular characteristics in terms of mechanical properties and microstructure, since they have high strength, high ductility and density reduction up to 18%. On the other hand, the addition of microalloying elements such as Ti and B generate hardening by solid solution and precipitation, as well as grain refinement effect. LD steels generate nano-sized kappa phase precipitated from the austenite matrix, and these advanced steels can reach strength and elongation up to 780 MPa and 60%, respectively. The main objective of this research work is the metallographic, structural and mechanical characterization of a LD steel microalloyed with Ti/B in as-cast and -homogenized conditions. For this purpose a Fe-27Mn-7Al-1.2C (%wt) LD steel microalloyed with Ti/B was melted in a vacuum-induction furnace and cast in metallic mold. LD-Ti/B steel samples were homogenized at 1100 °C during 20, 50, 100, 150 and 200 minutes followed by water quenching. Metallographic, structural and mechanical characterization was carried out by optical (LOM) and scanning electron (SEM) microscopy, X-ray diffraction (XRD) and microhardness Vickers testing (HV10), respectively. In general, results showed a typical dendritic microstructure with average grain size of 1256 μm in the as-cast condition. On the other hand, the as-homogenized condition showed an austenitic equiaxial microstructure with average grain size from 164 to 940 μm. Austenite, ferrite and kappa phases were detected by X-ray diffraction (XRD). Also, second-phase particles such as AlN, TiC and MnS were detected by LOM and SEM-EDS analysis. LD steel microalloyed with Ti/B exhibited the highest microhardness Vickers value (235 HV10) in the as-cast condition, whilst in the as-homogenized condition microhardness gradually decreases from 223 to 198 HV10 as holding time increases.

Thermolysis of Some Spirobenzopyran-3’,2-[1,3,4]oxadithiino- [5,6-c]benzopyran-4’-ones in the Presence of Some Homodienes and Crystallographic Studies of Some Adducts

2006 ◽  
Vol 61 (11) ◽  
pp. 1413-1420 ◽  
Author(s):  
Mohamed I. Hegab ◽  
A. M. Moustafa
Keyword(s):  
Single Crystal ◽  
The Other ◽  
X Ray Diffraction ◽  
X Ray ◽  
Other Hand ◽  
Good Support

The very reactive α-oxo-thioketone derivatives 2a - d, generated via thermolysis of spirobenzopyran- 3’,2-[1,3,4]oxadithiino[5,6-c]benzopyran-4’-ones 1a - d, reacted with 2,3-dimethyl-1,3-butadiene and 1,3-cyclohexadiene under [4+2]-cycloaddition to afford spirobenzopyran-3’,6-thiapyran-4’-one adducts 3a - d and spirobenzopyran-3’,3-thiabicyclo[2.2.2]oct-5-en-4’-one adducts 4a - d, respectively. On the other hand, the reaction of α-oxo-thioketones 2a - d with isoprene afforded regioselectively only 3-methyl-thiapyran derivatives 5a - d. Single crystal X-ray diffraction studies of 4b, 4c, and 5a give a good support for the established structure.

Reactions of tin(II) and tin(IV) xanthates: crystal structure of Tetrakis(O-ethylxanthato)tin(IV)

1978 ◽  
Vol 31 (7) ◽  
pp. 1493 ◽  
Author(s):  
CL Raston ◽  
PR Tennant ◽  
AH White ◽  
G Winter
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Least Squares ◽  
Coordination Sphere ◽  
The Other ◽  
X Ray Diffraction ◽  
Coordination Environment ◽  
X Ray ◽  
Monodentate Ligands

Tin(II) xanthates form adducts with donor molecules and react with excess xanthate to form the tris-xanthato ion, Sn(EtOCS2)3-. No such reactions are observed with tin(IV) xanthates. Reaction of quinolin-8- ol with tin(IV) ethylxanthate results in the replacement of two xanthate moieties by two oxinato ions. ��� The crystal structure of [Sn(EtOCS2)4] has been determined by single-crystal X-ray diffraction at 295 K and refined by least squares to a residual of 0.038 for 2378 'observed' reflections. The tin(IV) coordination environment resembles that observed in the N,N- diethyldithiocarbamate analogue, two of the xanthate ligands being monodentate and coordinating cis [Sn-S, 2.488(2), 2.499(2) Ǻ] in the six-coordinate coordination sphere while the other two ligands are bidentate, the Sn-S distances trans to the monodentate ligands being slightly longer [2.617(2), 2.627(2)Ǻ] than the other two [2.562(2), 2.539(2)Ǻ]. Crystals are monoclinic, P21/c, a 10.341(5), b 10.465(4), c 21.88(1) Ǻ, β 98.36(4)°, Z 4.

A NEW SUPERCONDUCTING MATERIAL IN A Y-Ba-Cu-O AND Bi-Ca-Sr-Cu-O MIXED SYSTEM

1989 ◽  
Vol 03 (05) ◽  
pp. 447-451
Author(s):  
M.A.K.L. DISSANAYAKE ◽  
K. TENNEKONE ◽  
O.A. ILEPERUMA ◽  
S.H.S.P. SAMARAPPULI
Keyword(s):  
Diffraction Pattern ◽  
Superconducting Phase ◽  
The Other ◽  
Mixed System ◽  
X Ray Diffraction ◽  
X Ray ◽  
Superconducting Material ◽  
Other Hand ◽  
Stoichiometric Ratios

A new superconducting phase has been found in a mixed system prepared from the YBa 2 Cu 3 O 7−δ and Bi 2 CaSr 2 Cu 2 O 9−δ high-T c materials. The new compound shows an onset of resistivity transition at ~100 K and zero resistivity below ~50 K. Powder X-ray diffraction pattern of the new compound differs completely from those of YBa 2 Cu 3 O 7−δ and Bi 2 CaSr 2 Cu 2 O 9−δ. The materials prepared using a mixture of the oxides and carbonates with identical cation stoichiometric ratios, on the other hand, does not exhibit superconductivity.

scholarly journals THE SPECIFIC HEAT AND THE HEAT OF COMPRESSION OF HUMAN RED CELLS, SICKLED RED CELLS, AND PARACRYSTALLINE RAT RED CELLS

1955 ◽  
Vol 38 (5) ◽  
pp. 575-580 ◽  
Author(s):  
Eric Ponder
Keyword(s):  
Thermal Properties ◽  
Specific Heat ◽  
Crystallization Process ◽  
Red Cells ◽  
The Other ◽  
Red Cell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Other Hand ◽  
Human Red Cells

The investigation of two thermal properties of red cells throws some light on whether sickling is a process involving the crystallization of a relatively insoluble hemoglobin. These properties are the specific heat and the heat of compression, both of which would be expected to become numerically less if the hemoglobin of the red cell were to crystallize. In the case of paracrystalline rat red cells, which give spacings at 45 A and 58 A by x-ray diffraction, the specific heat is reduced to 85 per cent of that of the normal red cells, and the heat of compression is only about 75 per cent of that found for the normal red cell. In the case of the red cell sickled by a reduction of the O2 tension, the specific heat and the heat of compression are substantially the same as found for the normal red cell. This is an argument against sickling being the result of a crystallization process, and supports the observation that sickled cells do not give x-ray spacings. The result is compatible, on the other hand, with sickling being the result of the formation of an oriented and birefringent gel.

scholarly journals Perbandingan porselen kedokteran gigi swa-sintesis berbahan baku pasir felspar Pangaribuan dan Sukabumi

2017 ◽  
Vol 3 (3) ◽  
pp. 49
Author(s):  
Joseph Gunawan ◽  
Dede Taufik ◽  
Veni Takarini ◽  
Zulia Hasratiningsih
Keyword(s):  
Potassium Salt ◽  
Raw Materials ◽  
The Other ◽  
Good Prospect ◽  
X Ray Diffraction ◽  
Natural Sand ◽  
Dental Porcelain ◽  
X Ray ◽  
Other Hand

Comparison self-synthesized dental porcelain between feldspar from Pangaribuan and Sukabumi. Dental porcelain material as one of the esthetic indirect restorations in Indonesia is mostly imported. In fact, Indonesia is really rich of natural raw materials, including feldspar, silica, and kaolinite. The aim of this study is to synthesize the dental porcelain made from Indonesia’s two different originates, which are Pangaribuan and Sukabumi. This study was prepared by fritting and sintering the mixture of 65% wt feldspar (from Sukabumi and Pangaribuan), 25% wt silica, 5% wt kaolinite, and 5% wt potassium salt. The porcelains obtained were evaluated using X-Ray Diffraction (XRD). The results revealed that quartz and leucite were found in the composition of Pangaribuan sand that successfully showed more translucencies compared to Sukabumi sand which only imparted quartz on its component. This study shows that dental porcelain from Pangaribuan sand is successfully self-synthesized, on the other hand Sukabumi sand has not been successfully synthesized. These findings develop on a good prospect of esthetic dental porcelain made from Indonesian natural sand. ABSTRAKBahan porselen kedokteran gigi sebagai salah satu restorasi indirek estetik di Indonesia kebanyakan didatangkan dari luar negeri. Indonesia sebenarnya sangat kaya dengan bahan baku porselen kedokteran gigi seperti felspar, silika, dan kaolin. Tujuan penelitian ini adalah melakukan sintesis porselen kedokteran gigi dari 2 jenis pasir alam Indonesia yaitu Pangaribuan dan Sukabumi. Komposisi yang digunakan yaitu 65% wt felspar, 25% wt silika, 5% wt kaolin, dan 5% wt garam kalium, dicampur kemudian dilakukan fritting serta sintering. Dua komposisi porselen dibuat dengan bahan dasar berbeda yaitu felspar dari Pangaribuan dan Sukabumi. Kedua porselen yang telah disintering kemudian dievaluasi menggunakan X-Ray Diffraction (XRD). Hasilnya adalah kuarsa dan leusit ditemukan pada porselen dengan komposisi pasir Pangaribuan yang juga memberikan hasil lebih translusen secara visual dibandingkan dengan porselen dengan komposisi pasir Sukabumi yang hanya memperlihatkan hasil kuarsa. Hal ini menunjukkan bahwa porselen dengan komposisi bahan dasar pasir Pangaribuan berhasil disintesis dibandingkan komposisi bahan dasar pasir Sukabumi.Penemuan ini dapat memberikan peluang yang baik dalam pembuatan porselen kedokteran gigi yang berasal dari pasir alam Indonesia. 

127I-NQR, 119 Sn Mössbauer Effect, and Electrical Conductivity of MSnI3 (M = K, NH4 , Rb, Cs, and CH3NH3 )

1990 ◽  
Vol 45 (3-4) ◽  
pp. 307-312 ◽  
Author(s):  
Koji Yamada ◽  
Takashi Matsui ◽  
Tomoko Tsuritani ◽  
Tsutomu Okuda ◽  
Sumio Ichiba
Keyword(s):  
Phase Transition ◽  
Electrical Conductivity ◽  
Structural Change ◽  
Mössbauer Effect ◽  
The Other ◽  
X Ray Diffraction ◽  
Mossbauer Effect ◽  
X Ray ◽  
Regular Octahedron ◽  
Other Hand

Abstract In a series of MSnI3 compounds (M = K, NH4 , Rb, Cs, CH3NH3) two types of coordination around the central Sn(II) were found by 127I-NQR and powder X-ray diffraction techniques. They are square pyramidal (for M = NH4 , Rb) and octahedral (for M = CH3NH3). CsSnI3 , on the other hand, showed a drastic structural change of the anion at 425 K from a square pyramid to a regular octahedron. Associated with this phase transition, the electrical conductivity increased from 4 x 10-3 S cm-1 to about 102 S cm-1 . This metallic modification was characterized by 127I-NQR and 119Sn Mössbauer spectroscopy.

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