Perchlorate and difluorophosphate coordination derivatives of rhenium carbonyl

1980 ◽  
Vol 33 (11) ◽  
pp. 2369 ◽  
Author(s):  
E Horn ◽  
MR Snow

The complexes Re(CO)5ClO4, Re(CO)5PO2F2, L2(CO)3Re(OClO3) and L2(CO)3Re(PO2F2), where L2 = 2,2?-bipyridyl (bpy), have been synthesized by bromide abstraction reactions from the respective rhenium carbonyl bromide precursors. The complexes were characterized by infrared and mass spectroscopy. The crystal structure of (bpy)(CO)3Re(PO2F2) has been determined from X-ray diffraction data by the heavy-atom technique. The crystals are triclinic, space group Pī with a 8.620(3), b 15.912(5), c 6.466(3) Ǻ, α 102.08(8), β 83.29(8), γ 95.08(4) and Z 2. The structure has been refined by full-matrix least-squares from 2829 reflections to R = 0.084, Rw = 0.088. The coordination geometry about rhenium is that of a distorted octahedron. Difluorophosphate coordinates to the metal centre by one of its oxygen atoms. Formation of the difluorophosphate by hydrolysis of hexafluorophosphate was shown by 31P n.m.r. spectra.


2005 ◽  
Vol 60 (9) ◽  
pp. 978-983 ◽  
Author(s):  
Sevim Hamamci ◽  
Veysel T. Yilmaz ◽  
William T. A. Harrison

Two new saccharinato-silver(I) (sac) complexes, [Ag(sac)(ampy)] (1), and [Ag2(sac)2(μ-aepy)2] (2), [ampy = 2-(aminomethyl)pyridine, aepy = 2-(2-aminoethyl)pyridine], have been prepared and characterized by elemental analysis, IR spectroscopy, thermal analysis and single crystal X-ray diffraction. Complexes 1 and 2 crystallize in the monoclinic space group P21/c and triclinic space group P1̄, respectively. The silver(I) ions in both complexes 1 and 2 exhibit a distorted T-shaped AgN3 coordination geometry. 1 consists of individual molecules connected into chains by N-H···O hydrogen bonds. There are two crystallographically distinct dimers in the unit cell of 2 and in each dimer, the aepy ligands act as a bridge between two silver(I) centers, resulting in short argentophilic contacts [Ag1···Ag1 = 3.0199(4) Å and Ag2···Ag2 = 2.9894(4) Å ]. Symmetry equivalent dimers of 2 are connected by N-H···O hydrogen bonds into chains, which are further linked by aromatic π(py)···π(py) stacking interactions into sheets.



1995 ◽  
Vol 48 (11) ◽  
pp. 1887 ◽  
Author(s):  
MI Bruce ◽  
PJ Low ◽  
BW Skelton ◽  
ERT Tiekink ◽  
A Werth ◽  
...  

The crystal and molecular structures of MBr (PPh3)2(η-C5H5).CH2Cl2 (M = Ru and Os) have been determined. A revised synthesis of the bromo osmium complex is given. The coordination geometry about the metal atom is based on a distorted octahedron with one face being occupied by the cyclopentadienyl group [average Ru -C(Cp) 2.214(3), Os-C(Cp) 2.177(3)Ǻ] and the other by the bromide [ Ru -Br 2.5683(8), Os-Br 2.5438(9)Ǻ] and the two phosphorus atoms [ Ru -P 2.323(2), 2.329(1); Os-P 2.290(2), 2.297(2)Ǻ]. Structural parameters are compared with those of the corresponding chloro complexes and differ only minimally. Crystals of MBr (PPh3)2(η-C5H5).CH2Cl2 are triclinic, space group Pī , with unit cell dimensions ( Ru [Os]): a 14.374(5) [14.276(4)], b 14.057(4) [13.959(3)], c 10.012(5) [9.903(3)]Ǻ, α 99.43(3) [99.79(2)], β 105.60(3) [105.74(2)], γ 100.42(3) [100.39(2)]°, V 1868(1) [1817.7(9)] Ǻ3, Z 2. The structures were refined by a full-matrix least-squares procedure to R 0.050 [0.036] for 7365 [5108] reflections with I ≥ 3σ(I).



1998 ◽  
Vol 51 (3) ◽  
pp. 219 ◽  
Author(s):  
Ian R. Whittall ◽  
Mark G. Humphrey ◽  
David C. R. Hockless

The structures of Ni(C≡CR)(PPh3)(η-C5H5) (R = Ph (1), C6H4-4-NO2 (2), 4-C6H4C6H4-4′-NO2 (3), (E)-4-C6H4CH=CHC6H4-4′-NO2 (4), 4-C6H4C≡CC6H4-4′-NO2 (5), 4-C6H4N=CHC6H4-4′-NO2 (6)) have been determined by single-crystal X-ray diffraction studies, refining by full-matrix least-squares analysis. For (1), crystals are triclinic, space group P-1, with a 10·094(2), b13·429(3), c 18·835(5) Å,α 103·24(2), β 91·50(2), γ 90·10(2)°, Z 4, 5844 unique reflections (595 parameters), converging at R 0·033 and Rw 0·024. For (2), crystals are orthorhombic, space group Pna21, with a 16·799(2), b 8·681(2), c 17·485(2) Å, Z 4, 1774 unique reflections (325 parameters), converging at R 0·031 and Rw 0·029. For (3), crystals are monoclinic, space group P 21/c, with a 11·140(3), b 18·282(4), c 15·296(2) Å, β 105·18(2)°, Z 4, 3132 unique reflections (397 parameters), converging at R 0·039 and Rw 0·024. For (4), crystals are monoclinic, space group P 21/n, with a 12·929(7), b 16·953(8), c 15·601(7) Å, β 112·55(3), Z 4, 3023 unique reflections (397 parameters), converging at R 0·039 and Rw 0·025. For (5), crystals are monoclinic, space group P 21/n, with a 12·710(5), b 16·882(3), c 15·693(4) Å, β 111·37(3)°, Z 4, 3216 unique reflections (397 parameters), converging at R 0·035 and Rw 0·030. For (6), crystals are monoclinic, space group P 21/n, with a 12·594(1), b 16·936(2), c 15·611(1) Å, β 112·476(5)°, Z 4, 3564 unique reflections (397 parameters), converging at R 0·038 and Rw 0·041. For structurally characterized 18-electron (cyclopentadienyl)nickel(II) acetylide complexes, statistically insignificant decreases in the average Ni-C(1) distance and trans influence and an increase in the average C(1)-C(2) parameter are observed on introduction of an acceptor substituent at the alkynyl ligand.



1999 ◽  
Vol 52 (10) ◽  
pp. 949 ◽  
Author(s):  
Martin A. Bennett ◽  
Glen B. Robertson ◽  
Pramesh N. Kapoor

Reaction of the cyclohexyne–platinum(0) complex [Pt(η2-C6H8)(Cy2PCH2CH2PCy2)]* with water and CO2 in the presence of triphenylphosphine gives the bicarbonate salt of the (η1-cyclohexenyl)platinum(II) cation, [Pt(η1-C6H9)(Cy2PCH2CH2 PCy2)(PPh3)] [HCO3] · 3H2O, which has been characterized by n.m.r. spectroscopy and single-crystal X-ray diffraction at low temperature. Crystals are triclinic, space group P1– with unit cell dimensions a 20.315(2), b 12.782(1), c 10.694(1) Å, α 66.61(1), β 104.73(1), γ 102.11(1)˚, and Z 2. The structure was refined to a final R value of 0.036 with use of 7553 reflections [I > 3σ(I)]. The cation has the expected, somewhat distorted planar coordination geometry; the anion consists of discrete, hydrogen-bonded dimers [(HCO3)(H2O)3]22-.



1972 ◽  
Vol 25 (10) ◽  
pp. 2117 ◽  
Author(s):  
MD Brice ◽  
BR Penfold ◽  
WT Robinson

The crystal and molecular structure of 4α-t-butylcyclohexane-1β,2,β-diol, C10H20O2, has been determined by X-ray diffraction methods. The compound crystallizes in the triclinic space group Pi with 4 molecules in a unit cell of dimensions a = 12.268, b = 15.921, c = 6.322�, α = 82.53, β = 114.45, γ = 111.13�. The intensity data were measured by counter methods using Cu Kα radiation; the structure was solved by means of the tangent formula, and was refined using full matrix least-squares techniques to a final R-factor of 0.063 for 1199 reflections. The crystal structure consists of two sets of crystallographically non-equivalent molecules hydrogen-bonded to form discrete chains parallel to the c axis. The cyclohexane rings are in the chair conformation.



2007 ◽  
Vol 72 (5-6) ◽  
pp. 637-648 ◽  
Author(s):  
Brian A. Salisbury ◽  
John F. Young ◽  
Glenn P. A. Yap ◽  
Klaus H. Theopold

Lithium 2,5-bis{[(2,6-diisopropylphenyl)imino]methyl}pyrrol-1-ide (LiL) reacts with [CrCl3(thf)3] to yield the octahedral complex [(η2-L)CrCl2(thf)2] (1), in which only two of the three potential nitrogen donors are coordinated to chromium. In the presence of various alkyl aluminum cocatalysts, 1 catalyzes the polymerization of ethylene. Attempts to prepare alkyl derivatives of 1 were thwarted by an apparent disproportionation, yielding divalent [(η2-L)(η1-L)Cr(thf)] (2). The molecular structures of 1 and 2 have been determined by X-ray diffraction. The structure of 2 is unusual in that it features weak, but equivalent interactions of both imine groups of the η1-pyrrolide ligands with the chromium, giving rise to an approximately octahedral coordination geometry with two extremely long Cr-N distances.



1990 ◽  
Vol 68 (10) ◽  
pp. 1901-1907 ◽  
Author(s):  
Tom Otieno ◽  
Steven J. Rettig ◽  
Robert C. Thompson ◽  
James Trotter

The complexes CuL2(CF3SO3) where L is pyrazine and 2,5-dimethylpyrazine have been prepared by the reaction of copper(I) triflate with the neutral ligand in methanol. Single crystal X-ray diffraction studies on the 2,5-Me2pyz complex are reported. Crystals of the compound are triclinic, a = 9.424(4), b = 12.103(4), c = 9.113(4) Å, α = 110.97(3), β = 117.20(3), γ = 80.26(3)°, Z = 2, space group [Formula: see text]. The structure was solved by heavy atom methods and was refined by full-matrix least-squares procedures to R = 0.033 and Rw = 0.039 for 3326 reflections with I ≥ 3σ(1). The structure is similar to that of the pyz analogue involving chains of copper ions linked by bridging 2,5-Me2pyz ligands and monodenate triflate and terminal 2,5-Me2pyz ligands completing a distorted tetrahedral CuN3O chromophore. Mono-pyrazine and -2,5-dimethylpyrazine complexes of the type CuL(CF3SO3) were obtained by thermolysis of the corresponding bis-ligand complexes. These compounds are assigned a polymeric structure involving bridging neutral ligands and monodenate triflate groups on the basis of infrared spectroscopy studies. Electronic spectroscopy and differential scanning calorimetry studies are also reported. Keywords: pyrazine and 2,5-dimethylpyrazine complexes, copper(I) triflate, crystal structure.



Author(s):  
Luong Xuan Dien ◽  
Nguyen Xuan Truong ◽  
Ken -ichi Yamashita ◽  
Ken- Ichi Sugiura

An innovative π-expanded ligand derived from salicylaldimine ligand representing pyrene ring as a substitute for benzene ring was synthesized in 5 steps from commercially available pyrene. This unique bidentate ligand (1) was coordinated to Cu(II) metal centre for affording complex 2, which was characterized by IR, elemental, X-ray diffraction analyses, and magnetic susceptibility. Its coordination geometry is a trans-square plane with an obvious stair-step structure which is formed by two pyrene moieties and the coordination plane (CuN2O2). In addition, the dihedral angle between the coordination plane and the pyrene ring is 34.9o and the plane of seven carbon atoms of the long alkyl chains were arranged nearly parallel to the pyrene rings. The electronic properties of this novel complex 2 were examined via cyclic voltammetry and absorption spectroscopy to show the narrower HOMO-LUMO gap than those of the complex 4. Moreover, the particular behavior of both complexes 2 and 4 was investigated through DFT studies.



2008 ◽  
Vol 63 (1) ◽  
pp. 77-82 ◽  
Author(s):  
Bao-Lin Li ◽  
Zhen-Guo Zhang ◽  
Wei Wang ◽  
Jin Li ◽  
Chou-Wen Wang

A green chemistry-based highly regioselective synthesis of ethyl (9-anthryl)glyoxylate was achieved by solvent-free Friedel-Crafts reaction at r. t. Several derivatives of ethyl (9-anthryl)glyoxylate were also synthesized. Ethyl (9-anthryl)hydroxyacetate was obtained almost quantitatively by reduction of ethyl (9-anthryl)glyoxylate with NaBH4, and (9-anthryl)methoxyacetic acid was prepared by methylation of ethyl (9-anthryl)hydroxyacetate with CH3I in the presence of Ag2O and hydrolysis of ethyl (9-anthryl)methoxyacetate. The hydrolysis of ethyl (9-anthryl)hydroxyacetate gave racemic (9-anthryl)hydroxyacetic acid, and the racemate was successfully resolved by crystallization of the diastereomeric salts resulting from the reaction of (±)-(9-anthryl)hydroxyacetic acid with (-)-ephedrine. As a byproduct, crystals containing racemic (±)-(9-anthryl)hydroxyacetate and protonated (-)-ephedrine were isolated and their structures determined by X-ray diffraction.



Author(s):  
Zhi-Guo Zhong ◽  
Yu-Quan Feng ◽  
Ping Zhang

A novel copper–niobium oxyfluoride, {[Cu2(C10H7N2O)2][NbOF4]}n, has been synthesized by a hydrothermal method and characterized by elemental analysis, EDS, IR, XPS and single-crystal X-ray diffraction. The structural unit consists of oneC2-symmetric [NbOF4]−anion and one centrosymmetric coordinated [Cu2(obpy)2]+cation (obpy is 2,2′-bipyridin-6-olate). In the [NbOF4]−anion, each NbVmetal centre is five-coordinated by four F atoms and one O atom in the first coordination shell, forming a square-pyramidal coordination geometry. These square pyramids are then further connected to each othervia transO atoms [Nb—O = 2.187 (3) Å], forming an infinite linear {[NbOF4]−}npolyanion. In the coordinated [Cu2(obpy)2]+cation, the oxidation state of each Cu site is disordered, which is confirmed by the XPS results. The disordered Cu sites are coordinated by two N atoms and one O atom from two different obpy ligands. The [NbOF4]−and [Cu2(obpy)2]+units are assembledviaweak C—H...F hydrogen bonds, resulting in the formation of a three-dimensional supramolecular structure. π–π stacking interactions between the pyridine rings [centroid–centroid distance = 3.610 (2) Å] may further stabilize the crystal structure.



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