The Crystal and Molecular Structure of Acetamidopentaamminecobalt(III) Perchlorate. A Conjugate Base of Nitrogen Bonded Acetamide

1973 ◽  
Vol 51 (13) ◽  
pp. 2180-2185 ◽  
Author(s):  
Michael Louis Schneider ◽  
George Ferguson ◽  
Robert James Balahura

The crystal and molecular structure of acetamidopentaamminecobalt(III) perchlorate, [CH3CONHCo(NH3)5]2+•2ClO4−, has been determined from three-dimensional X-ray data obtained by diffractometer methods. The crystals are monoclinic, space group [Formula: see text] with four formula units in a unit cell of dimensions a = 13.250(6), b = 10.318(6), c = 10.676(5) Å, β = 98.34(3)°. The structure has been refined by block-diagonal least-squares methods with anisotropic thermal parameters to a final residual R of 0.055 for 1340 observed reflexions. The crystal structure consists of discrete octahedral cations and tetrahedral perchlorate anions. The Co—N (amide) distance is short (1.911(8) Å) while the trans Co—N (ammine) bond is long (1.994(8) Å) compared to the equatorial Co—N distances which average 1.963(13) Å. The bond distances in the amide group, C—O 1.267(12) Å and C—N 1.339(12) Å, indicate that a delocalized system plays an important role in the ground state structure of the cation.


1975 ◽  
Vol 53 (13) ◽  
pp. 1949-1957 ◽  
Author(s):  
Roderic J. Restivo ◽  
Abraham Costin ◽  
George Ferguson ◽  
Arthur J. Carty

Copper(I) perchlorate, nitrate, and acetylacetonate complexes of the types Cu(triphos)ClO4 (triphos = CH3C(CH2PPh2)3), Cu(Cy3P)2ClO4 (Cy3P = P(C6H11)3), Cu(triphos)NO3, Cu(Cy3P)2(HFac)(HFac = hexafluoroacetylacetonate), and Cu (Cy3P)2(TtFac) (TtFac = thienyltrifluoroacetylacetonate) have been synthesized by reduction of the corresponding perchlorate, nitrate, and acetylacetonates with tertiary phosphines. Infrared spectra indicate the presence of monodentate perchlorate groups in Cu(triphos)ClO4 and in Cu(Cy3P)2ClO4 and the crystal structure of the latter has been determined by a three-dimensional X-ray analysis using diffractometer data. The crystals are monoclinic, space group C2/c, with cell dimensions a = 18.159(6), b = 9.493(2), c = 22.182(3) Å, and β = 95.41(2)° and four molecules per unit cell. The structure was refined by block-diagonal least squares methods to a final R of 0.051 for 2617 reflections using anisotropic thermal parameters for the nonhydrogen atoms. The structure consists of discrete Cu(Cy3P)2ClO4 molecules with symmetry C2 separated by normal van der Waals distances. The copper atom is three-coordinate and the perchlorate anion is monodentate but disordered over two sites. Principal dimensions include: Cu—P 2.262(1) Å, Cu—O 2.220(7) Å, [Formula: see text][Formula: see text] and 99.8(2)°, and [Formula: see text]



1972 ◽  
Vol 50 (14) ◽  
pp. 2276-2284 ◽  
Author(s):  
Brian W. Davies ◽  
Richard J. Puddephatt ◽  
Nicholas C. Payne

The crystal and molecular structure of trans-chloromethylbis(trimethylarsine)platinum(II) hexafluorobut-2-yne has been determined from three dimensional X-ray diffraction data recorded by diffractometric methods. The structure has been refined by full-matrix least-squares methods on F using 1156 reflections to an agreement factor R = 0.077. The crystals are monoclinic, space group [Formula: see text] with a = 6.803(8), b = 14.93(2), c = 20.20(2) Å, β = 104.9(1)°, and Z = 4. The coordination of the platinum atom is trigonal bipyramidal, with the acetylene considered a monodentate ligand, and the two trimethylarsine ligands occupying the equatorial plane. The chlorine atom and the methyl ligand occupy the apical positions, with Pt—Cl and Pt—C distances of 2.47(1) Å and 2.10(4) Å, respectively. The long Pt—Cl bond length indicates the strong trans-influence of the methyl ligand. The observed C—C bond length of 1.32(4) Å in the acetylene ligand is lengthened from the value of 1.22(9) Å measured in the free ligand. The geometry of the coordinated ligand is discussed in terms of the bonding scheme proposed by Greaves etal.



1975 ◽  
Vol 28 (10) ◽  
pp. 2129 ◽  
Author(s):  
GB Robertson ◽  
PO Whimp

The structure of a cobalt(III) tetraammine complex of 4,5-dihydroxy- 4,5-dimethyl-1-pyrroline-2-carboxylic acid (abbreviated as hmpc), (RS,RS)-[Co(NH3)4(hmpc)] (ClO4)2,H2O, has been determined from three- dimensional X-ray data collected by counter methods. Crystals are monoclinic, space group P21/c, with a 11.984(5), b 8.836(4), c 19.609(7) Ǻ, β 110.58(2)�, Z 4. The structure has been refined to weighted and unweighted R-factors of 0.068 and 0.063, respectively, for the 1616 independent reflections with I/σ(I) ≥ 3.0. Hydrogen atoms could not be located and have not been included in the scattering model. There is considerable steric strain within the substituted pyrroline ligand, and the C=N distance is 1.293(8) Ǻ. Surprisingly, the methyl groups in the 4- and 5-positions are in a cisoid configuration (the torsion angle for the methyl groups about the 4-5 bond is 39.5�), and consequently the hydroxyl oxygen atoms are close [O-O distance, 2.583(8) Ǻ]; this suggests that there may be a bridging hydrogen atom.



1978 ◽  
Vol 33 (1) ◽  
pp. 7-13 ◽  
Author(s):  
M. Veith

Abstract The crystal and molecular structure of the monoclinic phase of 1,3-di-tert-butyl-2,2-dimethyl-1,3,2,4λ2 -diazasilastannetidine has been determined from three-dimensional X-ray data collected on a two-circle diffractometer at -120 °C (MoKa radiation, 2623 reflexions, R - 0,050). The crystals are monoclinic, space group C2/c, with cell dimensions a = 10.655(5), b = 25.75(1), c = 17.33(1) Å, β = 106.8(1)° and Z = 12. Four monomeric (crystal site symmetry 2 (C2)) and four dimeric units (crystal site symmetry 1̄ (Ci)) are present in the structure interacting over tin-tin (3.68 Å). Remarkable are the very short Sn-N bond (2.09 Å) in the monomer and the donation bond Sn-N (2.39 Å) in the dimer. The coordination of the tin atoms in the different units is discussed in detail.



1979 ◽  
Vol 34 (3) ◽  
pp. 434-436 ◽  
Author(s):  
A. Müller ◽  
S. Pohl ◽  
M. Dartmann ◽  
J. P. Cohen ◽  
J. M. Bennett ◽  
...  

Abstract The novel tri-nuclear metal-sulfur cluster [Mo3S(S2)6]2- can be obtained as its ammonium salt by the reaction of a Moiv containing aqueous solutions with polysulfide. Its crystal and molecular structure has been determined by a single crystal X-ray study. The crystals are monoclinic (space group Cm, with a = 11.577(6) Å, b = 16.448(7) Å, c = 5.716(2) Å, β = 117.30(3)°, V = 967.2 Å3 , Z = 2, dexptl. = 2.54(2) g/cm3 , dcal = 2.54 g/cm3). The structure consists of isolated [Mo3S(S2)6]2- units, with three Mo atoms at the vertices of a triangle. There are bridging as well as terminal S22--ligands lying above and below the Mo3-plane (bond distances: Mo-Mo = 2.722 Å, Mo-S(terminal) = 2.435, Mo-S(bridging) = 2.452, Mo3-S = 2.353(4) Å and S-S = 2.04 Å (mean values)).



1986 ◽  
Vol 51 (11) ◽  
pp. 2521-2527 ◽  
Author(s):  
Jan Lokaj ◽  
Eleonóra Kellö ◽  
Viktor Kettmann ◽  
Viktor Vrábel ◽  
Vladimír Rattay

The crystal and molecular structure of SnBu2(pmdtc)2 has been solved by X-ray diffraction methods and refined by a block-diagonal least-squares procedure to R = 0.083 for 895 observed reflections. Monoclinic, space group C2, a = 19.893(6), b = 7.773(8), c = 12.947(8) . 10-10 m, β = 129.07(5)°, Z = 2, C20H38N2S4Sn. Measured and calculated densities are Dm = 1.38(2), Dc = 1.36 Mg m-3. Sn atom, placed on the twofold axes, is coordinated with four S atoms in the distances Sn-S 2.966(6) and 2.476(3) . 10-10 m. Coordination polyhedron is a strongly distorted octahedron. Ligand S2CN is planar.



1997 ◽  
Vol 52 (2) ◽  
pp. 256-258 ◽  
Author(s):  
Evgeni V. Avtomonov ◽  
Rainer Grüning ◽  
Jörg Lorberth

Abstract The crystal structure of the title compound has been determined by X-ray diffraction methods. Due to the Lewis acidic character of the iodine substituent a “zig-zag” chain is formed via intermolecular interactions (2.933(4) A) between iodine and oxygen atoms of theocarbamate moiety. A three-dimensional network is formed through hydrogen-bridging (2.04 A) between NH-groups and the oxygen atoms of the neighbouring carbamate group of the next molecule.



1981 ◽  
Vol 34 (4) ◽  
pp. 891 ◽  
Author(s):  
G Smith ◽  
EJ O'Reilly ◽  
CHL Kennard

The manganese(II) complex [Mn(picl)2,2H2O]n of the herbicide picloram has been prepared and the crystal and molecular structure determined from three-dimensional X-ray data collected by counter methods. The crystals of the complex are monoclinic, space group 12/a with two complex units in a cell of dimensions a 23·052(5), b 13·840(2), c 6·441(1) �, β 98·20(1)�. The structure was solved by direct methods and refined by full matrix least squares to unweighted and weighted Rfactors of 0·035 and 0·038 respectively for 887 'observed' reflections. The polymer is best described as having a centrosymmetric two-molecule unit [Mn-O, 2·162(3), 2·246(3) �] with two oxo bridges between manganese centres through two single carboxylate oxygens of the four substituted picolinate ligands. The two molecules are related by a twofold axis. The units form infinite one-dimensional polymer chains in the c direction through oxo bridges involving one oxygen from the other two picolinate ligands [Mn-Mn 3·636(1)�]. The bis(bidentate)picolinate bites are completed by the pyridlne nitrogens [Mn-N, 2·313(4) �] giving a very distorted octahedral MnO4N2 coordination sphere about each manganese [N-Mn-N', 97.0(3)�; O-Mn-O range, 68·9-168.2(3)�; O-Mn-Nrange, 69·9-138·5(3)�]. The lattice waters are involved in hydrogen-bonding interactions which link the polymer in the a crystallographic direction with the uncoordinated carboxylate oxygen ( O···O,2·824, 2·936 �) and the 4-amino groups from the adjacent picolinate ligand (N· ··0, 2·852, 3·030�).



1975 ◽  
Vol 53 (22) ◽  
pp. 3383-3387 ◽  
Author(s):  
Joseph Hubert ◽  
André L. Beauchamp ◽  
Roland Rivest

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.



1979 ◽  
Vol 57 (2) ◽  
pp. 174-179 ◽  
Author(s):  
A. Wallace Cordes ◽  
Paul F. Schubert ◽  
Richard T. Oakley

The crystal structure of 1,4-diphenyl-2,2′,3,3′,5,5′,6,6′-octamethylcyclo-1,4-diphospha-2,3,5,6-tetrasilahexane, (PhPSi2Me4)2, has been determined by single crystal X-ray diffraction. The crystals are monoclinic, space group P21/c, with a = 9.866(1), b = 11.921(1), and c = 11.324(2) Å, β = 104.31(1)°, Z = 2, and ρcalcd = 1.15 g/cm3. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final R of 0.060 and Rw of 0.078, for 1173 reflections with intensities greater than 3σ. The (PhPSi2Me4)2 molecule lies on a crystallographic centre of symmetry, and the six-membered P2Si4 ring has a chair conformation with equatorial phenyl groups. The endocyclic angles at P (104.4(1)°) and Si (104.9(2)°) are intermediate between those found in cyclic hexaphosphine and hexasilane molecules, and the Si—Si and P—Si distances of 2.345(3) and 2.252(4) Å, respectively, correspond to single bond lengths, with no appreciable evidence for secondary pπ → dπ bonding between phosphorus and silicon. The Si—C (1.867(8) Å) and P—C (1.828(7) Å) bond lengths are also normal. The variations in the Si—P—C (101.6(2)°, 108.6(2)°), P—Si—C (range 106.2(3)–120.0(3)°), and Si—Si—C (range 105.8(3)–113.7(3)°) angles indicate that the positions of the exocyclic methyl and phenyl groups are influenced by both intra- and intermolecular steric forces.



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