Addition of Alkynes to the Metal-Metal Double Bond in (η-C5Me,5)2Rh2(µ-CO)2; Crystal and Molecular Structure of the Complex (η-C5Me5)2Rh2(µ-CO){µ-C(O)C2(CF3)2}.

1985 ◽  
Vol 38 (2) ◽  
pp. 273 ◽  
Author(s):  
RS Dickson ◽  
GS Evans ◽  
GD Fallon
Keyword(s):  
Room Temperature ◽  
Variable Temperature ◽  
Heavy Atom ◽  
The Other ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
Arene Complex ◽  
Metal Metal ◽  
Rhodium Atom

Various alkynes (EtC2Et, MeO2CC2CO2Me, CF3C2CF3, PhC2Ph, C6F5C2C6F5, PhC2Me, PhC2C6-F5, PhC2CO2Me) react with (η-C5Me5)2Rh2(μ-CO)2 in acetone at room temperature; no reaction was observed with ButC2But. The σ-bridging alkyne complex, trans-(η-C5Me5)2Rh2(CO)2(μ-η1:η1C6F5C2C6F5), was obtained from the reaction with C6F5C2C6F5. With the other alkynes, dimetallaeneone complexes, (η-C5Me5)2Rh2(μ-CO){μ-η2:η2-C(O)C2RR′}, are formed. Some of these 'eneone' complexes co-exist with (η- C5Me5)2Rh2(CO)2(μ-η1:η1-RC2R�) in the solid state (RC2R� = PhC2C6F5) and/or in solution (EtC2Et, CF3C2CF3, PhC2C6F5); others (MeO2CC2CO2Me, PhC2Ph, PhC2Me, PhC2CO2Me) exist exclusively as (η-C5Me5)2Rh2(μ-CO){μ-η2:η2- C(O)C2RR′} in both the solid and solution states. The geometry of the bridging group in (η-C5Me5)2Rh2(μ-CO){μ-η2:η2-C(O)C2(CF3)2} has been determined from an X-ray diffraction study. The compound crystallizes with four molecules in the monoclinic space group P21/n in a unit cell of dimensions a 9.451(4), b 15.287(5), c 18.821(8)Ǻ, β 98.66(5)°. The structure was solved by conventional heavy atom methods and refined to R 0.066 based on 4356 observed reflections above background. The structure contains a metalla-eneone ring, Rh -C(=O)-C(CF3)=C(CF3), with the alkene bond η2-attached to the second rhodium atom. Variable temperature N.M.R . measurements establish that the complexes (η- C5Me5)2Rh2(μ-CO){μ-η2:η2-C(O)C2R2}(R = CF3 or CO2Me) are fluxional in solution. Facile cleavage of a C(O)-C(R) bond enables the metalla-eneone ring to shift rapidly from one rhodium atom to the other. Other products formed in the reactions between (η-C5Me5)2Rh2(μ-CO)2 and RC2R′ include. (η-C5Me5) Rh {C4(CF3)4CO}, (η-C5Me5) Rh (η4-C6R6) (R = CF3 or CO2Me), (η-C5Me5)2Rh2-(C4R2R′2) (R = R′ = CO2Me; or R, R′ = Ph, C6F5), (η- C5Me5)2Rh2(CO2C2Ph2), (η-C5Me5)- Rh (C4Ph4CO2), (η-C5Me5)2Rh2(CO)2{C4(CF3)4}, (η-C5Me5)2Rh2(CO)(μ-CO){COC4(C6F5)4} and C6R3R′3 (R = R′ = Ph or CO2Me; R = Ph and R′ = Me). Reactions between (η-C5Me5)2-Co2(μ-CO)2 and alkynes at room temperature or above yield mononuclear cyclopentadienone complexes (η-C5Me5)Co{C4R4CO}(R = Me, CF3 or C6F5), and the mononuclear arene complex (η-C5Me5)Co{C6(CF3)6}.

scholarly journals Crystal and molecular structure and 31P and 195Pt nmr spectroscopy of [Pt3S2(PMe2Ph)6][BEt4]2; a trinuclear complex containing triply-bridging sulphide ligands

1984 ◽  
Vol 62 (4) ◽  
pp. 696-702 ◽  
Author(s):  
Gordon William Bushnell ◽  
Keith Roger Dixon ◽  
Reiko Ono ◽  
Alan Pidcock
Keyword(s):  
Trinuclear Complex ◽  
Complete Analysis ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
Metal Interactions ◽  
Nuclear Magnetic Resonance Spectra ◽  
Square Planar ◽  
Metal Metal ◽  
Pd Complexes

An X-ray diffraction study of [Pt3S2(PMe2Ph)6][BEt4]2 shows that it crystallises in the monoclinic space group, C2/c, with a = 15.447(2), b = 18.033(3), c = 26.505(5) Å, β = 96.73(2)°. The cation consists of three, distorted, square-planar cis-PtS2(PMe2Ph)2 moieties combined by sharing of the two sulphur atoms to produce a central Pt3S2 unit with C2 symmetry and Pt—Pt distances of 3.182(1) Å (one edge) and 3.108(1) Å (two edges). Complete analysis and computer simulation of 31P{1H} and 195Pt{1H} nuclear magnetic resonance spectra give values for 1J(Pt—P), 3202 Hz; 3J(Pt—P), −25 Hz; and 2J(Pt—Pt), 476 Hz. The structure is compared with previous results for analogous Ni and Pd complexes and the structural and nmr parameters are discussed with reference to the possibility of metal–metal interactions.

The Crystal and Molecular Structures of Two Modifications of cis-Dichloro-mer-tris-(dimethylphenylphosphine)hydridoiridium(III)

1988 ◽  
Vol 41 (3) ◽  
pp. 283 ◽  
Author(s):  
GB Robertson ◽  
PA Tucker
Keyword(s):  
Heavy Atom ◽  
Molecular Structures ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray ◽  
Bond Lengths ◽  
Metal Ligand ◽  
Ligand Bond

The structures of two crystalline modifications of mer -(Pme2Ph)3H-cis-Cl2IrIII, (1), have been determined from single-crystal X-ray diffraction data. Modification (A) is monoclinic, space group P21/c with a 12.635(1), b 30.605(3), c 14.992(2)Ǻ, β 110.01(2)° and Z = 8. Modification (B) is orthorhombic, space group Pbca with a 27.646(3), b 11.366(1), c 17.252(2)Ǻ and Z = 8. The structures were solved by conventional heavy atom techniques and refined by full-matrix least- squares analyses to conventional R values of 0.037 [(A), 8845 independent reflections] and 0.028 [(B), 5291 independent reflections]. Important bond lengths [Ǻ] are Ir -P(trans to Cl ) 2.249(1) av. (A) and 2.234(1) (B), Ir -P(trans to PMe2Ph) 2.339(2) av. (A) and 2.344(1), 2.352(1) (B), Ir-Cl (trans to H) 2.492(2), 2.518(2) (A) and 2.503(1) (B) and Ir-Cl (trans to PMe2Ph)2.452(2) av. (A) and 2.449(1)(B). Differences in chemically equivalent metal- ligand bond lengths emphasize the importance of non-bonded contacts in determining those lengths.

scholarly journals The Isomorphous Structures of Ammonium trans-Diiodobis(ethanedial-dioximato-(1–)-N,N′)cobaltate(III) and Ammonium trans-Diiodobis(ethanedial-dioximato-(1–)-N,N′)rhodate(III): Extended Metaloximate Chains with a Novel ···I–M–I···I–M–I··· Zigzagged Structure

1990 ◽  
Vol 45 (11) ◽  
pp. 1508-1512 ◽  
Author(s):  
Michel Mégnamisi-Bélombé ◽  
Bernhard Nuber
Keyword(s):  
Room Temperature ◽  
Ammonium Salts ◽  
Monoclinic Space Group ◽  
Hydroxyl Groups ◽  
Coordination Geometry ◽  
Crystal Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Anionic Complexes ◽  
Complex Anions

The ammonium salts of the complex anions trans-diiodobis(ethanedial-dioximato)-cobaltate(III), [Col2(GH)2]-, and trans-diiodobis(ethanedial-dioximato)rhodate(III), [RhI2(GH)2]- (GH- = ethanedial dioximate or glyoximate), have been synthesized and their structures determined from single crystal X-ray diffraction data at room temperature. The crystals of the two salts are monoclinic, space group C2/c. NH4[CoI2(GH)2] (I) crystallizes as dark-brown prisms with a greenish reflectance; its crystal data are: C4H10Col2N5O4, Mr = 504.90; a = 8.910(6), b = 11.700(9), c = 11.691(6) Å; β = 93.55(5)°; V = 1216.4 Å3; Z = 4; Dc = 2.78 Mg m-3. NH4[RhI2(GH)2] (II) crystallizes as yellow-brown blocks with crystal data: C4H10I2N5O4Rh, Mr = 548.88; a = 9.038(4), b = 11.949(5), c = 11.770(3) Å; β = 95.54(3)°; V = 1265.16 A3; Z = 4; Dc = 2.87 Mg m-3. The two structures were refined to a final RW = 0.045 for 1209 observed independent reflections and 95 parameters for I, and to a final RW = 0.040 for 1922 observed independent reflections and 87 parameters for II. The coordination geometry around Co or Rh in the anionic complexes is a distorted (4 + 2) octahedron of four equatorial chelating N atoms and two apical iodides. The H atoms of the hydroxyl groups are involved, as usual, in intramolecular O—H—O bridges with uniform Ο···Ο separations of 2.582 Å for I, and 2.713 Å for II. The rectilinear I—Co—I or I—Rh—I triads form “infinite” zigzag chains extending parallel to the ab plane, with a weak I—I contact of 3.988 Å for I, and 4.010 Å for II.

The structures and phase transitions in 4-aminopyridinium tetraaquabis(sulfato)iron(III), (C5H7N2)[FeIII(H2O)4(SO4)2]

2019 ◽  
Vol 75 (6) ◽  
pp. 1144-1151
Author(s):  
Tamara J. Bednarchuk ◽  
Wolfgang Hornfeck ◽  
Vasyl Kinzhybalo ◽  
Zhengyang Zhou ◽  
Michal Dušek ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Single Crystal ◽  
Room Temperature ◽  
Variable Temperature ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Hybrid Compound ◽  
Space Group ◽  
X Ray

The organic–inorganic hybrid compound 4-aminopyridinium tetraaquabis(sulfato)iron(III), (C5H7N2)[FeIII(H2O)4(SO4)2] (4apFeS), was obtained by slow evaporation of the solvent at room temperature and characterized by single-crystal X-ray diffraction in the temperature range from 290 to 80 K. Differential scanning calorimetry revealed that the title compound undergoes a sequence of three reversible phase transitions, which has been verified by variable-temperature X-ray diffraction analysis during cooling–heating cycles over the temperature ranges 290–100–290 K. In the room-temperature phase (I), space group C2/c, oxygen atoms from the closest Fe-atom environment (octahedral) were disordered over two equivalent positions around a twofold axis. Two intermediate phases (II), (III) were solved and refined as incommensurately modulated structures, employing the superspace formalism applied to single-crystal X-ray diffraction data. Both structures can be described in the (3+1)-dimensional monoclinic X2/c(α,0,γ)0s superspace group (where X is ½, ½, 0, ½) with modulation wavevectors q = (0.2943, 0, 0.5640) and q = (0.3366, 0, 0.5544) for phases (II) and (III), respectively. The completely ordered low-temperature phase (IV) was refined with the twinning model in the triclinic P{\overline 1} space group, revealing the existence of two domains. The dynamics of the disordered anionic substructure in the 4apFeS crystal seems to play an essential role in the phase transition mechanisms. The discrete organic moieties were found to be fully ordered even at room temperature.

The Crystal and Molecular Structure of Pentane-2,4-dionato-(2,3,5,6-tetrahepto-2,3-dicarbomethoxo[2.2.1]bicycloheptadiene)rhodium(I), Rh(C5H7O2) (C7H6(CO2CH3)2)

1975 ◽  
Vol 53 (18) ◽  
pp. 2707-2713 ◽  
Author(s):  
Debbie Allen ◽  
Colin James Lyne Lock ◽  
Graham Turner ◽  
John Powell
Keyword(s):  
Crystal And Molecular Structure ◽  
Molecular Structures ◽  
Monoclinic Space Group ◽  
Intensity Data ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
X Ray ◽  
Crystal And Molecular Structures ◽  
Square Planar ◽  
Rhodium Atom

The crystal and molecular structures of pentane-2,4-dionato-(2,3,5,6-tetrahapto-2,3-dicarbomethoxo[2.2.1]bicycloheptadienerhodium(I), Rh(C5H7O2)(C7H6(CO2CH3)2), have been measured by single crystal X-ray diffraction. The orange crystals are monoclinic, space group P21/c, Z = 4, a = 9.245(4), b = 9.003(4), c = 21.680(15) Å, β = 113.41(5)°. The calculated and observed densities are 1.645 and 1.642(5) respectively. Intensity data were collected on a Syntex [Formula: see text] diffractometer and a full matrix least squares refinement on 3010 observed reflections leads to a conventional R = 0.0660. The structure can be considered as a roughly square planar arrangement of ligands around the rhodium atom composed of two β-ketoenolate oxygen atoms (Rh—O, 2.037(5) and 2.025(5) Å ) and the centers of the two ethylenic groups. The Rh—C distances for the olefin group attached to the two carbomethoxo groups, 2.117(8), 2.108(8) Å, appear to be slightly larger than those for the other olefinic group, 2.087(7), 2.082(6), and the corresponding C=C distances of 1.375(10) and 1.410(9) Å are different at the 95% confidence level.

A simple and inexpensive capillary furnace for variable-temperature X-ray diffraction

2008 ◽  
Vol 41 (1) ◽  
pp. 214-216 ◽  
Author(s):  
Christine Lavigueur ◽  
E. Johan Foster ◽  
Vance E. Williams
Keyword(s):  
Liquid Crystals ◽  
Temperature Control ◽  
Room Temperature ◽  
Variable Temperature ◽  
Target Temperature ◽  
Simple Design ◽  
X Ray Diffraction ◽  
Standard Temperature ◽  
X Ray ◽  
Transmission Geometry

An inexpensive capillary furnace has been developed for variable-temperature X-ray diffraction in transmission geometry of air-stable liquid crystals and other materials. It offers temperature control with fluctuations of less than ±1 K in the range of interest for these samples, from room temperature to near 573 K. Phases can be accessed through heating or cooling with no significant overshooting of the target temperature. The furnace is designed to fit on a classical goniometer, and can be controlled by any standard temperature controller. The simple design of this furnace means that it is both inexpensive to build and easy to operate.

Crystal and Molecular Structure of Dithiocyanato(triphenylarsine)mercury(II)

1975 ◽  
Vol 53 (22) ◽  
pp. 3383-3387 ◽  
Author(s):  
Joseph Hubert ◽  
André L. Beauchamp ◽  
Roland Rivest
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Coordination Number ◽  
Diffraction Data ◽  
Crystal And Molecular Structure ◽  
Heavy Atom ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heavy Atom Method

The crystal and molecular structure of dithiocyanato(triphenylarsine)mercury(II) has been determined from X-ray diffraction data. The crystals are monoclinic, space group P21/c, with a = 10.290(7), b = 21.199(23), c = 10.719(7) Å, β = 112.00(2)°, and Z = 4. The structure has been solved by the heavy-atom method and refined by block-diagonal least-squares calculations. The agreement factor R obtained for 2607 'observed' reflections is 0.030. The crystal consists of single molecules. The 'characteristic' coordination number of mercury is three, with two sulfur and one arsenic atoms at the apexes of a triangle. The nitrogen atoms of the thiocyanate groups are at 2.67 and 2.74 Å from the adjoining mercury atoms and therefore link the different molecules together.

Synthesis, structure, and magnetic properties of diphenylphosphinates of cobalt(II) and manganese(II). The crystal and molecular structures of the γ forms of poly-bis(μ-diphenylphosphinato)cobalt(II) and manganese(II)

1991 ◽  
Vol 69 (2) ◽  
pp. 277-285 ◽  
Author(s):  
Jing-Long Du ◽  
Steven J. Rettig ◽  
Robert C. Thompson ◽  
James Trotter
Keyword(s):  
Magnetic Properties ◽  
Heavy Atom ◽  
Molecular Structures ◽  
Antiferromagnetic Coupling ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Lattice Constants ◽  
Linear Chains

The synthesis of the β and γ forms of M(Ph2PO2)2 where M = Co and Mn are described and the compounds are characterized by infrared spectroscopy, differential scanning calorimetry, X-ray powder diffraction, and low-temperature (2–80 K) magnetic susceptibility studies. Single crystal X-ray diffraction studies are reported on the γ forms. Crystals of the γ forms of poly-bis(μ-diphenylphosphinato)cobalt(II) and poly-bis(μ-diphenylphosphinato)manganese(II) are isomorphous, crystallizing with 4 formula units per unit-cell in the monoclinic space group P21/c. Lattice constants are a = 8.080(2), 8.161(1), b = 23.550(6), 23.751(1), c = 11.726(3), 11.6946(6) Ǻ, and β = 92.88(2), 93.026(8)° for the Co and Mn derivatives respectively. The structures were solved by heavy atom methods and were refined by full-matrix least-squares procedures to R = 0.039 and 0.045 for 4041 and 2878 reflections with I ≥ 3σ(I), respectively. Both crystal structures consist of double phosphinate-bridged chain polymers containing tetrahedrally coordinated metal atoms: Co—O = 1.950(2)–1.963(2) Ǻ, O—Co—O = 104.81(8)–117.77(9)°, Mn—O = 2.016(3)–2.033(3) Ǻ, O—Mn—O = 103.2(1)–114.7(1)°. All four compounds exhibit antiferromagnetic coupling and magnetic susceptibilities have been analyzed according to two Heisenberg models for linear chains of metal ions with S = 3/2 for cobalt and S = 5/2 for manganese. The Weng model (with values for the Wagner and Friedberg model in parentheses) gives –J = 0.25 (0.26) cm−1 and 0.55 (0.60) cm−1 for the β and γ forms, respectively, of Co(Ph2PO2)2, and 0.34 (0.36) cm−1 and 0.17 (0.17) cm−1 for the β and γ forms, respectively, of Mn(Ph2PO2)2. Key words: crystal structure, diphenylphosphinates of cobalt(II) and manganese(II), magnetic properties.

Effect of Nd on Microstructures and Properties of AZ31 Wrought Mg Alloy

2007 ◽  
Vol 546-549 ◽  
pp. 301-304
Author(s):  
Wei Qiu ◽  
En Hou Han ◽  
Lu Liu
Keyword(s):  
Mechanical Properties ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Mg Alloys ◽  
The Other ◽  
Mg Alloy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microstructures And Mechanical Properties ◽  
Re Elements

Addition of RE elements to Al-containing Mg alloys can improve properties of Mg alloys at elevated temperatures. In the present investigation, hot-extruded AZ31+x%Nd. (x=0.1,0.3,0.6and1.0 wt%) wrought Mg alloy were prepared .The effects of Nd on microstructures and mechanical properties at room temperature of new alloy were investigated. The investigation found that Nd can bring about two kind of precipitation phases . One is AlNd phase, the other is AlNdMn phase, which were identified as Al11Nd3 and Al8NdMn4 by X-ray diffraction and TEM.

X-Ray Structure, Electrochemical and Electronic Spectroscopic Examination of Cobaloximatic Acid: Hydro-trans-diiodobis(ethanedioximato(1-)-N,N′)cobaltate(III). Extended Intermolecular O-H-O Bridging in the Solid

1993 ◽  
Vol 48 (10) ◽  
pp. 1360-1364
Author(s):  
Michel Mégnamisi-Bélombé ◽  
Irene Jokwi ◽  
Emmanuel Ngameni ◽  
Robert Roux ◽  
Bernhard Nuber
Keyword(s):  
Room Temperature ◽  
Strong Acid ◽  
Acetonitrile Solution ◽  
Monoclinic Space Group ◽  
Coordination Geometry ◽  
Crystal Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Acidic Proton ◽  
Spectroscopic Examination

The structure of the cobaloximatic acid, hydro-trans-diiodobis(ethanedioximato(1-)-N,N′)cobaltate(III), has been determined by X-ray diffraction. Crystal data: C4H7CoI2N4O4, Mr = 487.87; monoclinic space group P21/a (C2h5 ); a = 10.795(7), b = 9.003(7), c = 11.881(6) Å; β = 97.29(6)°; V = 1145.35 Å3; Z = 4; dc = 2.83 Mg m-3. Rw (R) = 3.6 (3.9)% for 3064 observed independent reflections and 148 parameters. The coordination geometry around CoIII is a distorted (4 + 2) octahedron of four chelating equatorial N atoms and two apical iodides. The compound is most adequately formulated as a monovalent strong acid: H(Co(GH)2I2) (GH- = ethanedioximate or glyoximate). The H atoms of the oxime groups are involved in the usual intramolecular, as well as in much stronger intermolecular O-H-O bridgings (O ••• Ointramol = 2.613-2.631, O ••• Ointramol = 2.454 A). The “acidic” H atom of each molecule participates in the intermolecular bridging which extends throughout the structure, and propagates nearly parallel to the [101] crystallographic direction. The redox properties of the present compound were examined by cyclic voltammetry in acetonitrile solution at room temperature. Redox waves attributed to the reduction of CoIII and to the oxidation of I- were observed, along with a wave which may be linked to the reduction of the “acidic” proton

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