The synthesis and seven-coordinate structure of (CH3)2AsC(CF3=C(CF3)As(CH3)2W(CO)Br2[P(OCH3)3]2

1986 ◽  
Vol 64 (5) ◽  
pp. 991-995 ◽  
Author(s):  
Lynn Mihichuk ◽  
Monica Pizzey ◽  
Beverly Robertson ◽  
Richard Barton
Keyword(s):  
Bromine Atom ◽  
Bidentate Ligand ◽  
Monoclinic Space Group ◽  
Coordinate Structure ◽  
Tungsten Atom ◽  
H Nmr ◽  
Nmr Data ◽  
R Value ◽  
Bond Trans ◽  
Trigonal Prismatic

(L–L)W(CO)4 (L–L = (CH3AsC(CF3)=C(CF3)As(CH3)2) is oxidized by Br2 to yield the seven-coordinate complex (L–L)W(CO)3Br2, which reacts with monodentate phosphines or phosphites to form (L–L)W(CO)Br2P2 (P = phosphine or phosphite). Crystals of (L–L)W(CO)Br2[P(OCH3)3]2 are monoclinic, space group P21/c, a = 19.110(5), b = 9.208(3), c = 17.845(6) Å, β = 108.93(2)° at 21 °C with Z = 4. The structure was solved from a Patterson map and refined by least squares to a conventional R value of 0.092 using 2330 independent reflections. The crystal structure indicated the tungsten atom to be seven-coordinate with the geometry most closely approximated by a capped trigonal prismatic environment, the capping group being a bromine atom (W—Br, 2.686(5) Å). The capped face consists of the remaining bromine atom (W—Br, 2.695(5) Å), a phosphorus atom (W—P, 2.465(9) Å), and the two arsenic atoms from the bidentate ligand (W—As, 2.619(3) and 2.526(4) Å). The W—As bond trans to a phosphite is significantly longer (by 0.093 Å) than the W—As bond trans to a bromine. The 1H nmr data indicate that the complex is stereochemically rigid at 25 °C and nonrigid at higher temperatures; however, the data at 25 °C are not consistent with the configuration found in the crystal.

Seven coordination. 1. Synthesis, structure, and fluxionality of(CH3)2AsC(CF3)=C(CF3)As(CH3)2W(CO)2I2P(OCH3)3

1987 ◽  
Vol 65 (11) ◽  
pp. 2634-2638 ◽  
Author(s):  
Lynn M. Mihichuk ◽  
Carolyn L. Giesinger ◽  
Beverly E. Robertson ◽  
Richard J. Barton
Keyword(s):  
Iodine Atom ◽  
Monoclinic Space Group ◽  
Arsenic Atom ◽  
Tungsten Atom ◽  
H Nmr ◽  
Nmr Data ◽  
Octahedral Environment ◽  
Exchange Processes ◽  
R Value ◽  
Bond Trans

(L—L)W(CO)4 (L—L = (CH3)2AsC(CF3)=C(CF3)As(CH3)2) is oxidized by I2 to yield the seven-coordinate complex (L—L)W(CO)3I2 which reacts with monodentate phosphines or phosphites to form (L—L)W(CO)2I2P (P = phosphine or phosphite). Crystals of (L—L)W(CO)2I2P(OCH3)3 are monoclinic, space group P21/c, a = 15.711(3), b = 13.134(2), c = 13.800(3) Å, β = 111.81(2)° with Z = 4. The structure was solved from a Patterson map and anisotropically refined by least squares to a conventional R value of 0.039 using 3737 independent reflections. The crystal structure showed the tungsten atom to be seven-coordinate with a geometry most closely approximated by a capped octahedral environment, the capping group being a carbonyl moiety ([W—C] = 1.95 (1) Å). The capped face consists of the carbon atom ([W—C] = 1.98(1) Å) of the remaining carbonyl, an arsenic atom ([W—As] = 2.556(1) Å), and the phosphorus atom ([W—P] = 2.466(3) Å). The W—As bond trans to a phosphite group is longer (by 0.050(2) Å) than the W—As bond trans to an iodine atom. 1H nmr data indicate the complex to be fluxional at 298 K and rigid at lower temperatures, the data at lower temperatures being consistent with the configuration found in the crystal. The nmr data at lower temperatures suggest two exchange processes are occurring; one which averages two sets of As—CH3 groups and another process which averages all four As—CH3 groups.

X-Ray Structure of a Nickel(II) Complex of the Tetra-N-methylated Macrocycle Dibenzocyclam with a Folded Ligand Configuration

1984 ◽  
Vol 39 (7) ◽  
pp. 903-906 ◽  
Author(s):  
Horst Elias ◽  
Rüdiger Grewe ◽  
Dirk-Detlev Klaehn ◽  
Helmut Paulus
Keyword(s):  
Three Dimensional ◽  
Bidentate Ligand ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Nitrate Ion ◽  
Light Blue ◽  
X Ray ◽  
Mild Conditions ◽  
Distorted Octahedral ◽  
R Value

Under mild conditions nickel(II) nitrate reacts with the macrocyclic N4 ligand TMBC ( = 1,4 ,8,11-tetramethyl-1,4,8,11-tetraazadibenzo[b,i]cyclotetradecane) to form the light blue-green complex Ni (TMBC) (NO3)2. A three-dimensional X-ray diffraction study shows that the complex crystallizes in the monoclinic space group P21/c with a = 896.1(3) pm, b = 2059.9(7) pm , c = 1298.6(6) pm, β = 91.37(1)° and Z = 4. The nickel is six-coordinate. The distorted octahedral N4O2 arrangement of donor atoms around the nickel is formed by the tetradentate N4 macrocycle TMBC in an unexpected folded form and by a nitrate ion as a bidentate ligand occupying two depositions. The structure could be refined to the final R-value of 0.045 only by assuming disorder for the second, noncoordinated nitrate ion.

4,4-Dimethyl-A-homocholestane derivatives

1981 ◽  
Vol 46 (3) ◽  
pp. 607-625 ◽  
Author(s):  
Helena Velgová ◽  
Jorga Smolíková
Keyword(s):  
Bromine Atom ◽  
Equilibrium Mixture ◽  
H Nmr ◽  
Nmr Data ◽  
Predominant Component ◽  
Equatorial Conformer

The synthesis of epimeric bromo ketones VII, VIII, XXV and XXVI, derived from 4,4-dimethyl-A-homo-4a-cholesten-3-one (I) and 4,4-dimethyl-A-homo-5-cholesten-3-one (XIII) is described in this paper. In the case of bromo ketones VII, VIII and XXV the IR data demonstrate the presence of conformers both with a quasi-axial and a quasi-equatorial bromine atom in the equilibrium mixture, the quasi-equatorial conformer being the predominant component. On the basis of IR, CD and 1H-NMR data the conformation of the ring A in compounds VII, VIII, XXV and XXVI is discussed.

scholarly journals Structural studies of steric effects in phosphine complexes. Part XI. Synthesis, characterization, crystal and molecular structure of the dinitrato(trimesitylarsine)mercury(II) dimer

1983 ◽  
Vol 61 (2) ◽  
pp. 257-262 ◽  
Author(s):  
Elmer C. Alyea ◽  
Shelton A. Dias ◽  
George Ferguson ◽  
Pik Y. Siew
Keyword(s):  
Molecular Structure ◽  
Crystal And Molecular Structure ◽  
Cone Angle ◽  
Mean Value ◽  
Monoclinic Space Group ◽  
Structural Studies ◽  
Torsion Angles ◽  
H Nmr ◽  
Phosphine Complexes ◽  
Nmr Data

The synthesis and crystal and molecular structure of the dinitrato(trimesitylarsine)mercury(II) dimer are reported. The compound [HgAs(mesityl)3(NO3)2]2 belongs to the monoclinic space group P21/c[Formula: see text] with a = 20.001(2), b = 17.591(5), c = 16.553(2), β = 99.991(6), and Z = 4; the asymmetric unit contains two independent half dimers. The structure was refined to a final R of 0.0458 for 2631 observed reflections measured by diffractometer with 2 < θ < 20°. The crystal structure consists of discrete centrosymmetric dimeric molecules of [HgAs(mesityl)3(NO3)2]2 separated by normal van der Waals distances. The mercury coordination in both dimers I and II is characterized by three strong, nearly coplanar bonds (in I Hg—As 2.476(3), Hg—O 2.41(2) and 2.20(2), and in II Hg—As 2.482(3), Hg—O 2.28(2) and 2.39(2), and three weaker Hg—O bonds in the range 2.55–2.90 Å. Both independent trimesitylarsine ligands have the same regular propeller conformation (Hg—As—C—C torsion angles of 45 to 50°) and the largest C—As—C angles (mean value 112.5(8)°) yet determined. The As(mesityl)3 cone angle is 202°. The two independent dimers differ primarily in the orientation of the non-bridging nitrato groups. Nitrato vibrational and arsine 1H nmr data are also presented for [HgAs(mesityl)3(NO3)2]2, which becomes monomeric in dichloroethane solution.

Chemie polyfunktioneller Moleküle, 80 [1]. Kristall- und Molekülstrukturen der Heteronoradamantane 5-Methyl-2.2.8.8-tetra-ethoxycarbonyl-1.3.7-triarsa-tricyclo[3.3.1.03,7]nonan und 5-Methyl-1.3.7-triarsa-2.8-diselena-tricyclo[3.3.1.03,7]nonan / Chemistry of Polyfunctional Molecules, 80 [1]. Crystal and Molecular Structures of the Heteronoradam antanes 5-Methyl-2.2.8.8-tetra-ethoxycarbonyl-1.3.7-triarsa-tricyclo[3.3.1.03,7]nonane and 5-M ethyl-1.3.7-triarsa-2.8-diselena-[3.3.1.03,7]nonane

1984 ◽  
Vol 39 (10) ◽  
pp. 1344-1349 ◽  
Author(s):  
Gerhard Thiele ◽  
Heinz W. Rotter ◽  
Martin Lietz ◽  
Jochen Ellermann
Keyword(s):  
Crystal Structures ◽  
Vibrational Spectroscopy ◽  
Molecular Structures ◽  
Monoclinic Space Group ◽  
Triclinic Space Group ◽  
Space Group ◽  
H Nmr ◽  
Crystal And Molecular Structures ◽  
Molecular And Crystal Structures ◽  
R Value

The molecular and crystal structures of the nor-heteroadam antanes CH3C(CH2As)3[C(COOCH2CH3)2]2 (1) and CH3C(CH2As)3Se2 (2) have been investigated in order to obtain confirmation of the rare structures deduced earlier from mass, 1H NMR and vibrational spectroscopy. Crystals of 1 are triclinic, space group P1̄-C1i with a - 769.27(30), b = 1036.09(14), c = 1599.18(17) pm, α = 98.236(10)°, β = 97.987(18)°, γ = 103.633(20)° and Z = 2. On the basis of 1821 unique reflections the structure was refined to a weighted R value of 5.28%. The crystals of 2 are monoclinic, space group P 21/c-C52h with a = 1102.73(23), b - 727.49(14), c = 1281.27(42) pm. β = 98.803(21)° and Z = 4. On the basis of 1065 unique reflections the structure was refined to a weighted R value of 5.93%.Several attempts to synthesize CH3C(CH2As)3Te2 failed.

The crystal and molecular structures of bromotricarbonyl(phenylbis(3,5-dimethylpyrazolyl)phosphine)rhenium(I) and tricarbonyl(phenylbis(3,5-dimethylpyrazolyl)phosphine)tungsten(0)

1979 ◽  
Vol 57 (17) ◽  
pp. 2285-2291 ◽  
Author(s):  
R. E. Cobbledick ◽  
L. R. J. Dowdell ◽  
F. W. B. Einstein ◽  
J. K. Hoyano ◽  
L. K. Peterson
Keyword(s):  
Phenyl Ring ◽  
Bromine Atom ◽  
Octahedral Geometry ◽  
Molecular Structures ◽  
Monoclinic Space Group ◽  
Carbonyl Groups ◽  
Tungsten Atom ◽  
Space Group ◽  
Crystal And Molecular Structures ◽  
Rhenium Complex

Crystals of [Re(CO)3(P(Me2pz)2C6H5)Br] (where Me2pz is 3,5-dimethylpyrazolyl) are monoclinic, space group P21/c, with a = 8.964(4), b = 14.441(10), c = 18.156(8) Å, β = 111.32(4)°, and Z = 4. Crystals of W(CO)3(P(Me2pz)2(C6H5)) are monoclinic, space group P21/c, with a = 12.479(7), b = 10.207(4), c = 16.118(7) Å, β = 98.77(2)°, and Z = 4. In both structures there is irregular octahedral geometry about the metal atom with the carbonyl groups in a fac arrangement. The phenylbis(3,5-dimethylpyrazolyl)phosphine ligand, [P(Me2pz)2(C6H5)], is coordinated to the tungsten atom through the two 2N nitrogen atoms of the pyrazolyl rings and to two carbon atoms of the phenyl ring so that the ligand is essentially tridentate. In the rhenium complex this ligand is bidentate with coordination via the 2N nitrogen atoms with a bromine atom occupying the sixth site.

Supramoleküle aus Kronenethern und geminalen Sulfonen: Synthese von vier binären Komplexen und Kristallstruktur von (CH2CH2O)4·2H 2C(SO2C2H5)2/Supramolecules of Crown Ethers with Geminal Sulfones: Synthesis of Four Binary Complexes and Crystal Structure of (CH2CH2O )4·2H2C(SO2C2H5)2

1995 ◽  
Vol 50 (7) ◽  
pp. 1018-1024 ◽  
Author(s):  
Axel Michalides ◽  
Dagmar Henschel ◽  
Armand Blaschette ◽  
Peter G. Jones
Keyword(s):  
Monoclinic Space Group ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Binary Complexes ◽  
Cyclic Polyethers ◽  
Adjacent Unit ◽  
Methylene Group

In a systematic search for supramolecular complexes involving all combinations of the cyclic polyethers 12-crown-4 (12C4), 15-crown-5 (15C 5), 18-crown-6 (18C 6) and dibenzo- 18-crown-6 (DB -18C6), and the geminal di- or trisulfones H2C(SO 2Me)2, H2C (SO2Et)2 and HC (SO2Me)3-n (SO2Et)n (n = 0 -3 ) , only the following four complexes could be isolated and unequivocally characterized by elemental analysis and 1H NMR spectroscopy: [(12C4){H2C (SO2Et)2}2] (3), [(18C6){H2C (S O2Me)2}] (4), [(DB -18C 6){H2C (SO2Et)2}] (5) and [(D B -18C 6)2{HC (SO2Me )(SO2Et)2}3] (6). The structure of 3 (triclinic, space group P1̄) consists of crystallographically centrosymmetric formula units, in which the disulfone molecules are bonded on each side of the ring by two C -H ··· O(crown) interactions originating from the central methylene group (H···O 213 pm) and from the methylene group of one EtSO2 moiety ( H ··· O 237 pm). Formula units related by translation are connected into parallel strands by a third type of reciprocal C -H ···O bond (H ···O 232 pm) between the second H atom of the central methylene group and a sulfonyl oxygen atom of the adjacent unit. The structure of 4 (monoclinic, space group C2/c) showed severe disorder of the crown ether and could not be refined satisfactorily. Compounds 5 and 6 crystallized as long and extremely thin fibres, indicative of linear-polymeric supramolecular structures; single crystals for X-ray crystallography were not available.

Inhibited rotation of amide group around C N bond of nicotinamide in different solvents by 1 H NMR data

2017 ◽  
Vol 231 ◽  
pp. 238-241 ◽  
Author(s):  
G.A. Gamov ◽  
V.V. Aleksandriiskii ◽  
V.A. Sharnin
Keyword(s):  
Amide Group ◽  
H Nmr ◽  
Nmr Data

Chemie polyfunktioneller Moleküle, 108 Tetraedrische Kupfer(I)-Chelatkomplexe der Liganden Bis(diphenylphosphino)amin und Bis(diphenylphosphino)methan / Chemistry of Polyfunctional Molecules, 108 [1] Tetrahedral Copper(I) Chelate Complexes with the Ligands Bis(diphenylphosphino)amine and Bis(diphenylphosphino)methane

1991 ◽  
Vol 46 (12) ◽  
pp. 1699-1705 ◽  
Author(s):  
Jochen Ellermann ◽  
Falk A. Knoch ◽  
Klaus J. Meier
Keyword(s):  
Membered Ring ◽  
Monoclinic Space Group ◽  
Direct Reaction ◽  
Conductivity Data ◽  
Chelate Complexes ◽  
X Ray ◽  
Lattice Constants ◽  
H Nmr ◽  
Highly Strained ◽  
Nitrate Anions

Reaction of [Cu(PPh3)2(NO3)] (1) in acetone with bis(diphenylphosphino)amine (dppa, 2) yields [Cu(dppa)(PPh3)2]+NO3- (3a). [Cu(dppa)(PPh3)2]+PF6- (3b) has been synthesized by metatheses of 3a with NH4PF6. The salt [Cu(dppm)(PPh3)2]+PF6- (5b) has been prepared by an one batch reaction of [Cu(PPh3)2(NO3)] (1), bis(diphenylphosphino)methane (dppm, 4) and NH4PF6 in methanol, because [Cu(dppm)(PPh3)2]+NO3- (5a) could not be isolated by the direct reaction of 1 with 4. The IR, Raman, 31P{1H} NMR, 1H{31Ρ} NMR as well as the conductivity data are reported and discussed together with the X-ray crystal structure of 3a · 1.8 (CH3)2CO. The structure consists of copper atoms coordinated tetrahedrally by two PPh3 ligands and the chelating dppa ligand and features a highly strained four-membered ring. The distorted tetrahedral cations are hydrogen bridged to the nitrate anions. The colourless needles of 3a· 1.8 (CH3)2CO crystallize in the monoclinic space group C 2/c, with the lattice constants a = 4189.2(27); b = 1223.7(8); c = 2717.8(15) pm;β = 113.16(4)°.

[Zn(phen)2(CX3COO)]+, X = H orCl; Influence of X on the Coordination Mode of the Carboxylate Group (phen = 1,10-Phenanthroline)

2005 ◽  
Vol 60 (10) ◽  
pp. 1049-1053 ◽  
Author(s):  
Zeanab Talaei ◽  
Ali Morsali ◽  
Ali R. Mahjoub
Keyword(s):  
Nmr Spectroscopy ◽  
Elemental Analysis ◽  
Coordination Mode ◽  
Bidentate Ligand ◽  
Carboxylate Group ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Coordinate Geometry ◽  
C Nmr

Two new ZnII(phen)2 complexes with trichloroacetate and acetate anions, [Zn(phen)2(CCl3COO)- (H2O)](ClO4) and [Zn(phen)2(CH3COO)](ClO4), have been synthesized and characterized by elemental analysis, IR, 1H NMR, 13C NMR spectroscopy. The single crystal X-ray data of these compounds show the Zn atoms to have six-coordinate geometry. From IR spectra and X-ray crystallography it is established that the coordination of the COO− group is different for trichloroacetate and acetate. The former acts as a monodentate whereas the latter acts as a bidentate ligand.

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