Crystal and molecular structure of a cobalt(III) ammine complex of 2-Amino-4-imino-2-methylpentanoic acid

1975 ◽  
Vol 28 (4) ◽  
pp. 729 ◽  
Author(s):  
GB Robertson ◽  
PO Whimp
Keyword(s):  
Molecular Structure ◽  
Crystal And Molecular Structure ◽  
Complex Cation ◽  
Three Dimensional ◽  
Cobalt Atom ◽  
Monoclinic Space Group ◽  
Hydrogen Atoms ◽  
Ammine Complex ◽  
Coordination Sites ◽  
Acid Ligand

The crystal and molecular structure of a cobalt(III) ammine complex of 2-amino-4-imino-2-methyl-pentanoic acid, [Co(NH3)3{HN=C(CH3)CH2C(CH3)(NH2)(CO2)}]S2O6, has been determined from three-dimensional X-ray data collected by counter methods. The complex crystallizes in the monoclinic space group P21/c (C52h, No. 14), with a = 7.576(4), b = 18.209(7), c = 14.068(6) Ǻ, β = 125.25(2)�, Z = 4. The structure was solved by conventional Patterson and Fourier methods, and was refined by block-diagonal least-squares methods to weighted and unweighted 12-factors of 0.041 and 0.040 respectively, for the 1479 unique reflections having I/σ(I) ≥ 3.0. All hydrogen atoms have been located and refined. The complex cation is essentially octahedral about the central cobalt atom with three amine groups occupying mutually cis coordination sites; the three remaining sites at the cobalt atom are occupied by the tridentate 2-amino-4-imino-2-methylpentanoic acid ligand. The Co-O distance is 1.914(4) Ǻ, while the Co-N(imine) distance is 1.924(5) Ǻ. The Co-N(NH3) distances range from 1.968(5) to 1.979(5) Ǻ, and are equal within experimental error. Within the tridentate 2- amino-4-imino-2-methylpentanoic acid ligand, the C=N distance is 1.252(7) Ǻ, while at the carboxyl group the ?free? C-O distance [1.233(6) Ǻ] is significantly shorter than the distance from the carbon to the coordinated oxygen atom [1.270(7) Ǻ]. In the S2O6 counter anion, the S-S distance is 2.112(2) Ǻ, and the S-O distances range from 1.434(6) to 1.457(4) Ǻ, averaging 1.439 Ǻ.

Crystal and molecular structure of (RS,RS)-Tetraammine(4,5-dihydroxy-4,5-dimethyl-1-pyrroline-2-carboxylato)cobalt(III) perchlorate

1975 ◽  
Vol 28 (10) ◽  
pp. 2129 ◽  
Author(s):  
GB Robertson ◽  
PO Whimp
Keyword(s):  
Molecular Structure ◽  
Hydrogen Atom ◽  
Crystal And Molecular Structure ◽  
Three Dimensional ◽  
Methyl Groups ◽  
Monoclinic Space Group ◽  
Hydrogen Atoms ◽  
Steric Strain ◽  
X Ray ◽  
R Factors

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.

Crystal and molecular structure of Bis(4-amino-3,5,6-trichloropicolinato)-manganese(II) dihydrate

1981 ◽  
Vol 34 (4) ◽  
pp. 891 ◽  
Author(s):  
G Smith ◽  
EJ O'Reilly ◽  
CHL Kennard
Keyword(s):  
Molecular Structure ◽  
Crystal And Molecular Structure ◽  
Three Dimensional ◽  
Direct Methods ◽  
Polymer Chains ◽  
Monoclinic Space Group ◽  
Carboxylate Oxygen ◽  
Group 12 ◽  
Distorted Octahedral ◽  
A Cell

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�).

Crystal and Molecular Structure of Difluorochlorine(III)-hexafluoroarsenate(V), ClF2AsF6

1971 ◽  
Vol 49 (15) ◽  
pp. 2539-2543 ◽  
Author(s):  
H. Lynton ◽  
J. Passmore
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Chlorine Atom ◽  
Crystal And Molecular Structure ◽  
Three Dimensional ◽  
Monoclinic Space Group ◽  
Arsenic Atom ◽  
Space Group

Crystals of difluorochlorine(III)hexafluoroarsenate(V), ClF2AsF6, are monoclinic, space group A2/a, a = 10.676(9), b = 7.673(7), c = 8.064(7) Å, β = 113.40(5)°. The structure was refined by three dimensional least squares methods to R = 0.045 for 185 independent observed reflections. The chlorine atom has two nearest fluorine neighbors at 1.541(14) Å, with a F—Cl—F angle of 103.17(0.70)°, and two longer fluorine bonds at 2.339(14) Å. All five atoms lie in a plane. The arsenic atom is octahedrally coordinated to six fluorine atoms and is connected to two ClF2+ groups via trans fluorine bridges.

The crystal and molecular structure of streptomycin oxime selenate tetrahydrate

1978 ◽  
Vol 359 (1698) ◽  
pp. 365-388 ◽  
Keyword(s):  
Molecular Structure ◽  
Crystal And Molecular Structure ◽  
Heavy Atom ◽  
Water Molecules ◽  
Monoclinic Space Group ◽  
Hydrogen Atoms ◽  
Glycosidic Bonds ◽  
Compound C ◽  
Cell Dimensions ◽  
Network Of Hydrogen Bonds

The crystal and molecular structure and absolute configuration of the antibiotic streptomycin have been determined by an X-ray study of the hydrated oxime selenate. The compound (C 21 H 40 N 8 O 12 . 1 1/2 H 2 SeO 4 .4H 2 O) crystallizes in the monoclinic space group C 2, with cell dimensions a = 17.10(1), b = 14.36(1), c = 16.13(1)Å∥, β = 108.0(2)°; Z = 4 The structure was solved by the heavy-atom method, by using 3236 visually-estimated intensities, and refined to a conventional R of 0.086. The analysis has confirmed that streptomycin consists of three fragments, an N -methyl- α-L-glucosamine ring, an α-L-streptose and a streptidine ring, linked together by two glycosidic bonds. The crystal structure contains an elaborate network of hydrogen bonds linking selenate and streptomycin oxime ions and water molecules, analysis of which, though somewhat hampered by inability to observe the hydrogen atoms experimentally, reveals a disordered hydrogen bond occurring between two diad-related water molecules.

Perchlorato, Nitrato, and Acetylacetonato Complexes of Copper(I). The Crystal and Molecular Structure of Perchloratobis(tricyclohexyiphosphine)Copper(I)

1975 ◽  
Vol 53 (13) ◽  
pp. 1949-1957 ◽  
Author(s):  
Roderic J. Restivo ◽  
Abraham Costin ◽  
George Ferguson ◽  
Arthur J. Carty
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Infrared Spectra ◽  
Copper Atom ◽  
Crystal And Molecular Structure ◽  
Three Dimensional ◽  
Monoclinic Space Group ◽  
X Ray ◽  
Tertiary Phosphines ◽  
Cell Dimensions

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]

An Intermediate in the Conversion of an Acetylene to a Vinyl Derivative: The Crystal and Molecular Structure of trans-Chloromethylbis(trimethylarsine)-platinum(II) Hexafluorobut-2-yne

1972 ◽  
Vol 50 (14) ◽  
pp. 2276-2284 ◽  
Author(s):  
Brian W. Davies ◽  
Richard J. Puddephatt ◽  
Nicholas C. Payne
Keyword(s):  
Molecular Structure ◽  
Bond Length ◽  
Crystal And Molecular Structure ◽  
Three Dimensional ◽  
Free Ligand ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Monodentate Ligand ◽  
X Ray ◽  
Trigonal Bipyramidal

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.

The structural features of a tetrahedral 1,3-monothiolate complex: The crystal and molecular structure of Bis(ethyl 3-mercaptobut-2-enoato)zinc(II)

1977 ◽  
Vol 30 (5) ◽  
pp. 993 ◽  
Author(s):  
BF Hoskins ◽  
CD Pannan
Keyword(s):  
Molecular Structure ◽  
Least Squares Method ◽  
Crystal And Molecular Structure ◽  
Lone Pair ◽  
Structural Features ◽  
The Other ◽  
Zinc Atom ◽  
Monoclinic Space Group ◽  
Hydrogen Atoms ◽  
Mean Values

The crystal and molecular structure of bis(ethy 3-mercaptobut-2- enoato)zinc(II) has been determined by single-crystal X-ray diffraction techniques. Solved by conventional Patterson and Fourier methods the structure was refined by a least-squares method employing anisotropic thermal parameters to all non-hydrogen atoms to R and Rw values of 0.040 and 0.046 respectively. The complex crystallizes in the monoclinic space group P21/c with four molecules in a unit cell of dimensions a 11.107(1), b 18.239(2) and c 8.438(1) Ǻ and β 107.7(1)�. The intensities of 2274 independent and statistically significant [I ≥ 3σ(I)] reflections with θ values ≤ 70� were measured by counter methods using nickel- filtered Cu Kα radiation. The crystals comprise discrete monomeric molecules with the zinc atom bonded to two sulphur atoms and two oxygen atoms giving a coordination arrangement which is substantially distorted from an ideal tetrahedron. The mean values for the Zn-S and Zn-O bond distances are 2.247(1) and 2.007(3) Ǻ respectively and the average S-Zn-O intraligand bond angle is 99.25(8)�. The geometries of the ligands differ in two ways. Firstly, the two ethyl groups adopt differing conformations and secondly, while one ligand moiety is essentially planar with the zinc atom displaced about 0.1 Ǻ from that plane, the displaced atom in the other ligand is the carbon bonded to the sulphur atom and not the metal which is, in this instance, coplanar with the other members of the ring. Bond distances in each chelate ring indicate aromatic character with a lone pair of electrons on the ethoxy-oxygen participating in the delocalization.

The Crystal and Molecular Structure of trans-Dichloro-mer-trans-bis (triisopropylphosphine)(phosphine)hydridoiridium(III)

1995 ◽  
Vol 48 (7) ◽  
pp. 1277 ◽  
Author(s):  
EJ Ditzel ◽  
GB Robertson
Keyword(s):  
Molecular Structure ◽  
Transition Metal ◽  
Crystal And Molecular Structure ◽  
Structure Refinement ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Hydrogen Atoms ◽  
Full Matrix ◽  
X Ray ◽  
Molecular Dimensions

The structure of mer-trans-(PPri3)2(PH3)H-trans-Cl2IrIII (1) (Pri = isopropyl), the second third-row transition-metal-PH3 complex to be so characterized, has been determined by single-crystal X-ray diffraction analysis. Crystals are monoclinic, space group C 2/c with a 21.701(2), b 8.735(1), c 15.594(1) Ǻ, β 119.57(1)° and Z 4. Structure refinement by full-matrix least-squares analysis (2811 reflections, 113 parameters) converged with R = 0.016 and Rw = 0.022. Molecules exhibit crystallographically imposed C2 symmetry. The C2 axis passes through the iridium, hydride and PH3 phosphorus atoms, and requires the PH3 hydrogen atoms to be disordered. Important molecular dimensions are Ir-PPri3 2.371(1) Ǻ, Ir-PH3 2.362(1) Ǻ, Ir-Cl 2.374(1) Ǻ and P- Ir -P(trans) 163.21(3)°.

The crystal and molecular structure of tetrakis(trifluoromethyl)cyclopentadienone- π -cyclopentadienyl cobalt

1964 ◽  
Vol 279 (1377) ◽  
pp. 170-190 ◽  
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Least Squares ◽  
Molecular Conformation ◽  
Crystal And Molecular Structure ◽  
Three Dimensional ◽  
Cobalt Atom ◽  
Organometallic Complexes ◽  
Atomic Interactions ◽  
Monoclinic Cell

(CF 3 ) 4 C 5 O. C 5 H 5 . Co crystallizes in a monoclinic cell: a = 25·39 Å, b = 8·68 Å, c = 14·40 Å, β = 94·8°; Z = 8, C 2/ c . A least squares analysis of three-dimensional precession data has reduced the discrepancy index to 0·088, cobalt-carbon distances being reported with an e. s. d. of 0·023 Å and other bond lengths with an e. s. d. of 0·032 Å. A system of σ - and π -bonding from the cyclopentadienone ligand to the cobalt atom is evident from the molecular conformation, a comparison being made with the stereochemistry and bonding in other organometallic complexes. Other features of the molecular and crystal structure are discussed in relation to features of the non-bonded atomic interactions.

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
Keyword(s):  
Molecular Structure ◽  
Crystal And Molecular Structure ◽  
Three Dimensional ◽  
Amide Group ◽  
Ground State Structure ◽  
Monoclinic Space Group ◽  
State Structure ◽  
X Ray ◽  
Octahedral Cations ◽  
Conjugate Base

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.

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