Metal-Mediated Assembly of Hexameric Ethylcycloarsoxane (C2H5AsO)6 in Mono-and Dinuclear Complexes with Tetrahedral and Octahedral Coordination Spheres

1997 ◽  
Vol 52 (6) ◽  
pp. 679-686 ◽  
Author(s):  
Thomas Häusler ◽  
William S. Sheldrick
Keyword(s):  
Structure Analysis ◽  
Ring Expansion ◽  
The Other ◽  
Dinuclear Complexes ◽  
Ir Absorption ◽  
Absorption Bands ◽  
Ring Strain ◽  
X Ray ◽  
Mononuclear Complexes ◽  
Coordination Spheres

Abstract A metal-assisted ring expansion from the preferred solution species (EtAsO)n, n = 3,4, to the hexameric ligand (EtAsO)6 is observed for the reactions of [ReBr(CO)5], [RuCL2(Ph3P)3], RhCl3 ·3H2O and [Cu2CF3SO3)2(C6H6)] with ethylcycloarsoxane. Whereas two metal frag­ments are facially coordinated by the upper and lower three As atoms of a flattened As6O6 cuboctahedron in both [{ReBr(CO)2}2 {μ-[cyclo-(EtAsO)6]}] (1) and [Cu2{μ-[cyclo-(EtAsO)6]}(Me2PhP)2](CF3SO3)2 (4), potential ring strain restricts the reaction with the other compounds to the formation of mononuclear complexes [RuCl2{cyvclo-(EtAsO)6}(Ph3P)] (2)and [RhCl3{cyclo-(EtAsO)6}] (3) with k3As1,3,5 coordination. The structures of 1 - 4 were established by X-ray structure analysis. A shift in the ν(As-O) IR absorption bands to higher wavenumbers (830 - 788 cm-1 ) is characteristic for (EtAsO)6 complexes in comparison to those of the cyclic tetramer (781-747 cm-1 ).

scholarly journals Zum Substituenteneinfluß in neuen Ni(0)-Butadiin-Komplexen / On the Influence of Substituents in New Ni(0) Butadiyne Complexes

1995 ◽  
Vol 50 (3) ◽  
pp. 377-384 ◽  
Author(s):  
Uwe Rosenthal ◽  
Siegmar Pulst ◽  
Perdita Arndt ◽  
Wolfgang Baumann ◽  
Annegret Tillack ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Structure Analysis ◽  
Triple Bond ◽  
Crystal Structure Analysis ◽  
Dinuclear Complexes ◽  
X Ray ◽  
Mononuclear Complexes ◽  
Structural Details ◽  
Alkyne Complexes ◽  
Influence Of Substituents

It has been shown that disubstituted butadiynes react with (Ph3P)2Ni(C2H4) [1] or (cod)2Ni [2] in the presence of Ph3P to yield mononuclear complexes (Ph3P)2Ni(η2(1 :2 ) - R'C ≡ C - C ≡CR) (R' = R = SiMe3 (1), tBu (2) Ph (3) and R' = tBu, R = SiMe3 (4) or R' = Ph, R = SiMe3 (5)) or dinuclear complexes {(Ph3P)2Ni}2(μ-η2(1 :2),η2(3 :4) - R'C ≡C - C ≡CR ) (R' = R = SiMe3 (6), Ph (7)) depending on the stoichiometry applied. For R' = R = tBu or R' = tBu, R = SiMe3 the dinuclear complexes could not be obtained. Some of the mononuclear complexes with symmetrical (R' = R = SiMe3, tBu, Ph) and unsymmetrical disubstituted (R' = tBu, R = SiMe3) butadiynes have been characterized by X-ray crystal structure analysis to study the influence of different substituents on the structural details of the bonding. As compared to the alkyne complexes (Ph3P)2Ni(η2-RC ≡CR ) the influence of the different substituents in mononuclear butadiyne-complexes (Ph3P)2Ni(η2(1:2) - R'C ≡C - C ≡CR ) is strongly diminished by the conjugated uncomplexed C ≡C triple bond.

Preparation of Carboranyl and Dodecaborate Derivatives of Coumarin

2007 ◽  
Vol 72 (12) ◽  
pp. 1740-1754 ◽  
Author(s):  
Eugen Justus ◽  
Dana T. Izteleuova ◽  
Alexander V. Kasantsev ◽  
Mendel M. Axartov ◽  
Enno Lork ◽  
...  
Keyword(s):  
Structure Analysis ◽  
The Other ◽  
Magnesium Salt ◽  
Ester Bond ◽  
Coumarin Derivatives ◽  
X Ray ◽  
Derivatives Of ◽  
Coumarin Ring

A series of derivatives of coumarin (2H-chromen-2-one) and 6,7-benzocoumarin (3H-benzo-[f]chromen-3-one) carrying the o-carborane, m-carborane, and dodecaborate clusters, has been obtained. X-ray structure analysis has been carried out for three of the products. The addition of o-carborane occurs in the 4-position of the coumarin ring, in a stereoselective way, independent of whether the cluster was reacted as the lithium or magnesium salt. m-Carborane gives two products, one being the result of 1,2-addition to an exocyclic ester bond and 1,4-addition to the coumarin system, the other resulting from 1,4-addition. The negatively charged dodecaborate derivatives obtained, link the cluster via oxygen or sulfur and an appropriate linker to a 7-hydroxy-substituted coumarin. For the coumarin derivatives, an o-carboranecarbonyl derivative could also be obtained.

Modification of Sol-Gel Thin Films By Ion Implantation

1994 ◽  
Vol 346 ◽  
Author(s):  
Hiroshi Hirashima ◽  
Kenji Adachi ◽  
Hiroaki Imai
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Ion Implantation ◽  
Sol Gel ◽  
The Other ◽  
Ir Absorption ◽  
Absorption Bands ◽  
Chemically Modified ◽  
Sol Gel Films ◽  
Ion Species

ABSTRACTIn order to densify and to improve the physical properties, TiO2 sol-gel films, about 100 nm in thickness, on silica glass or silicon wafer were implanted with Ar+ or B+ ions. The refractive index of the as-dried films increased and the IR absorption band of OH disappeared after Ar+ implantation. Drying and densification of sol-gel films were enhanced by Ar+ implantation. On the other hand, the refractive index and the thickness of the films hardly changed with B+ implantation. However, IR absorption bands of B-O bond were observed after B+ implantation. This suggests that sol-gel films could be chemically modified by ion implantation with reactive ion species.

Local ordering of chromium(III) in trioctahedral hydroxide sheets of stichtite studied by ion exchange chromatography

Clay Minerals ◽  
1996 ◽  
Vol 31 (1) ◽  
pp. 53-61 ◽  
Author(s):  
H. C. B. Hansen ◽  
C. Bender Koch
Keyword(s):  
Ion Chromatography ◽  
Exchange Chromatography ◽  
Cation Ordering ◽  
Ir Absorption ◽  
X Ray Diffraction ◽  
Visible Spectroscopy ◽  
Acid Dissolution ◽  
Absorption Bands ◽  
X Ray ◽  
Local Ordering

AbstractStichtite is the layered Mg-Cr(III) hydroxide carbonate of the pyroaurite group. The possibility of describing Cr(III) short range order (SRO) in stichtite by use of ion chromatography of the Cr(III)-hydroxo species following acid dissolution of the compound is described. Two synthetic stichtites of similar composition (average Mg5.73Cr(III)2.27(OH)15.93(O)0.07(CO3)1.10·xH2O) prepared in the absence or presence of hydroxy-bridged Cr(III) dimers and a sample from Dundas, Tasmania, Mg6.29Ni(II)0.02Cr(III)0.90Al0.65Fe(III)0.15(OH)15.26(OH2)0.74(CO3)1.23·xH2O have been examined. Ion chromatography showed the highest degree of SRO for the Dundas stichtite. For the synthetic stichtites the sample synthesized from Cr(III) dimers had the highest SRO. No information on cation ordering could be extracted from powder X-ray diffraction data. Visible spectroscopy indicates that for constant Mg:Cr(III) ratio the crystal field splitting increases with increasing SRO. Two different OH-stretching IR absorption bands (3585 and 3472 cm−1) are assigned to OH coordinated to 3Mg and OH coordinated to 2MgCr or Mg2Cr, respectively.

Preparation and 31P NMR characterization of N-bonded complexes of platinum(II) with a phosphadithiatriazine: X-ray structure of trans-PtCl2(Pet3)(η1-N-Ph2PS2N3)

1992 ◽  
Vol 70 (10) ◽  
pp. 2602-2606 ◽  
Author(s):  
Tristram Chivers ◽  
Robert W. Hilts ◽  
Ian H. Krouse ◽  
A. Wallace Cordes ◽  
Randal Hallford ◽  
...  
Keyword(s):  
Nitrogen Atom ◽  
Free Ligand ◽  
Heterocyclic Ring ◽  
Structural Features ◽  
The Other ◽  
Monoclinic Space Group ◽  
Hydrogen Atoms ◽  
Absorption Bands ◽  
X Ray ◽  
Nmr Characterization

The reaction of Ph2PS2N3 with [Pt2(μ-Cl)2(PEt3)4][BF4]2 or [PtCl2(PEt3)]2, in dichloromethane at 23° C produces the 1:1 adducts cis-[PtCl(PEt3)2(Ph2PS2N3)][BF4], 3, and trans-[PtCl2(PEt3)(Ph2PS3N2)], 4, respectively, in good yields. The 31P NMR data for 3 and 4 indicate that (i) the platinum is attached to a nitrogen atom adjacent to phosphorus in both these adducts, (ii) the PEt3 ligands in 3 are in mutually cis positions, and (iii) the PEt3 ligand in 4 is trans to the heterocyclic nitrogen. These structural features were confirmed by an X-ray analysis of 4. Crystals of 4 are monoclinic, space group P21/c, with a = 14.920(3) Å, b = 8.966(5) Å, c = 19.103(5) Å, β = 109.32(2)°, V = 2411.6(16) Å3, and Z = 4. The least-squares refinement with anisotropic thermal parameters for all non-hydrogen atoms converged at R = 0.050 and Rw = 0.053. The Pt—N bond length is 2.122(15) Å and the coordinated nitrogen atom is lifted ca. 0.63(2) Å out of the plane containing the other heterocyclic ring atoms. The attachment of a platinum(II) centre to the PN3S2 ring perturbs the S—N bond lengths significantly. The S—N distance involving the coordinated nitrogen is 1.672(16) Å, while the other S—N distances are 1.631(19), 1.555(19), and 1.562(19) Å, indicative of a localized sulfur diimide (-N=S=N-) structure. The UV–visible spectra of 3 and 4 in CH2Cl2 exhibit absorption bands at 514 and 528 nm, respectively, but dissociation of these adducts to give the free ligand Ph2PS2N3 occurs readily in dilute solution.

Beiträge zur Chemie des Bors, 168 [1] Synthese und Struktur von Azadiboriridinen / Contributions to the Chemistry of Boron, 168 [1] Synthesis and Structure of Azadiboriridines

1986 ◽  
Vol 41 (1) ◽  
pp. 32-37 ◽  
Author(s):  
Franz Dirschl ◽  
Elisabeth Hanecker ◽  
Heinrich Nöth ◽  
Wilfried Rattay ◽  
Walter Wagner
Keyword(s):  
Low Temperature ◽  
Structure Analysis ◽  
Ring System ◽  
The Other ◽  
Ring Plane ◽  
X Ray ◽  
Restricted Rotation

Two representatives of the three membered B2N-ring system have been obtained by dehalogenation of diborylamines Me3CN[BHalNR2]2. In solution there is no restricted rotation at the exocyclic BN bond, even at low temperature. In contrast, the X-ray structure analysis of the bis-tetramethylpiperidino derivative 10a reveals alternation of short and long BN bonds; one of the tetramethylpiperidino groups stands nearly coplanar with the B2N-ring system, the other, however, is almost perpendicular to the ring plane. The ring contains a short BB bond (1.612 Å).

scholarly journals Structure determination of a novel metal-organic compound synthesized from aluminum and 2,5-pyridinedicarboxylic acid

2011 ◽  
Vol 26 (S1) ◽  
pp. S44-S46 ◽  
Author(s):  
Kenny Ståhl ◽  
Bastian Brink ◽  
Jonas Andersen
Keyword(s):  
The Other ◽  
Dinuclear Complexes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Triclinic System ◽  
Aluminum Ions ◽  
Pyridinedicarboxylic Acid ◽  
Distorted Octahedra ◽  
Metal Organic

The structure of [Al2(pydc)2(μ2-OH)2(H2O)2]n(pydc = 2,5-pyridinedicarboxylate) was successfully determined from powder X-ray diffraction data. The compound crystallizes in the triclinic system (space group P -1) with a = 6.7813(1) Å, b = 7.4944(1) Å, c = 8.5013(1) Å, α = 95.256(1)°, β = 102.478(1)°, γ = 108.979(1)°. The structure consists of aluminum ions coordinating N and O in distorted octahedra, sharing an edge through two hydroxide ions. These dinuclear complexes are connected by pydc ions, which at one end coordinate by nitrogen and oxygen and only by oxygen at the other end. The pydc orientation is reversed in the neighboring pydc, forming double stranded chains interconnected by the aluminum dinuclear complexes in a ladder-like arrangement along [001].

Nitrosolate und verwandte Verbindungen, XII Nitrosolatokomplexe von Silber(I) / Nitrosolates and Related Compounds, XII Nitrosolato Complexes of Silver(I)

1992 ◽  
Vol 47 (11) ◽  
pp. 1571-1579 ◽  
Author(s):  
Falk Olbrich ◽  
Bärbel Zimmer ◽  
Michael Kastner ◽  
Carl von Schlabrendorff ◽  
Gottlieb Vetter ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Liquid Ammonia ◽  
Layer Structure ◽  
Dinuclear Complexes ◽  
Chelating Ligands ◽  
Structural Units ◽  
Bridging Ligands ◽  
X Ray ◽  
Mononuclear Complexes ◽  
Related Compounds

X-ray analysis shows silver(I) aminomethylnitrosolate to have dimers as structural units, in which the W-shaped nitrosolate ions act as μ2-bridging ligands via the nitrogen atoms of the NO groups. The nearly planar dinuclear complexes form stacks, which are connected by additional AgO contacts leading to a kind of layer structure. These layers are held together by hydrogen bonds.Mononuclear complexes of composition [Ag(nitrosolate)L2] can be obtained from silver(I) ethylnitrosolate and bipyridyl in methanol and from silver(I) benzylnitrosolate and triphenylphosphane in diethylether/liquid ammonia. In these complexes the nitrosolate ions are supposed to act as chelating ligands, again with N,N′-coordination.

Oxidative Abbaureaktionen des homonuklearen Cobalthydridclusters [(η5-Cp*)Co]3H4 / Oxidative Degradation Reactions of the Homonuclear Cobalt Hydride Cluster [(η5-Cp*)Co]3H4

1995 ◽  
Vol 50 (4) ◽  
pp. 448-459 ◽  
Author(s):  
Jörg J. Schneider ◽  
Richard Goddard ◽  
Carl Krüger
Keyword(s):  
Crystal Structures ◽  
Oxidative Degradation ◽  
Dinuclear Complexes ◽  
X Ray ◽  
X Ray Crystallography ◽  
Degradation Reactions ◽  
Mononuclear Complexes ◽  
Metal Metal ◽  
Inorganic Substrates ◽  
Cobalt Compounds

The homonuclear cobalt cluster [(η5-Cp*)Co]3H4 2 reacts with various organic and inorganic substrates with complete degradation of the cluster core to afford mainly mononuclear organometallic cobalt compounds. Thus, whereas reaction of the cluster with CO, NO or alkynes results in the retention of the Co3 ring, the cluster reacts with Br2, I2, I2/CO , I2/ P(C 2H5)3, CCl4, HCI3, (CH2)2Br2, Hacac, CH2Br2, (C6H5CO)OOC(CH3)3, HBF4, and BrCN to give mononuclear complexes or bridged dinuclear complexes without a metal-metal bond. In all cases formal oxidation of the metal center is observed. The crystal structures of six organocobalt complexes have been determined by X-ray crystallography.

scholarly journals Electron Release and Proton Acceptance Reactions of (dpp-BIAN)Mg(THF)3

2008 ◽  
Vol 63 (2) ◽  
pp. 161-168 ◽  
Author(s):  
Igor L. Fedushkin ◽  
Valentina A. Chudakova ◽  
Markus Hummert ◽  
Herbert Schumann
Keyword(s):  
Nmr Spectroscopy ◽  
Carboxylic Acid ◽  
Ir Spectroscopy ◽  
The Other ◽  
X Ray ◽  
H Nmr ◽  
Trigonal Bipyramidal ◽  
Electron Release ◽  
Coordination Spheres ◽  
Centrosymmetric Dimers

(dpp-BIAN)Mg(THF)3 (1) (dpp-BIAN = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene) and (PhCOO)2 react with splitting of the peroxide bridge and formation of the dimeric magnesium benzoate [(dpp-BIAN)MgOCOPh(THF)]2 (2). The reaction of 1 with PhCOOH yields the dimeric magnesium benzoate [(dpp-BIAN)(H)MgOCOPh(THF)]2 (3), whereas 1 and furanyl-2-carboxylic acid react with liberation of hydrogen and formation of (dpp-BIAN)Mg[OCO(2-C4H3O)]2 Mg(dpp-BIAN)(THF) (4). Compounds 2, 3, and 4 have been characterized by elemental analysis, IR spectroscopy, and X-ray structure analysis, compound 3 also by 1H NMR spectroscopy. The eightmembered metallacycles of the centrosymmetric dimers 2 and 3 are almost completely planar. The two magnesium atoms in 4 show different coordination spheres; one is surrounded by its ligands in a trigonal bipyramidal manner, the other one in a tetrahedral fashion. The Mg···Mg separations in 2, 3 and 4 are 4.236, 4.296, and 4.030 Å, respectively

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