Insights into the van der Waals Radius of Low-Spin Ni(ii) fromMolecular Mechanics Studies and the Crystal Structures of [Ni(cis-cyclohexane-1,3-diamine)2]Cl2, [Ni{(R)-5,5,7-trimethyl-1,4-diazacycloheptane}2]Cl2·H2O and [Ni(5,7-dimethyl-1,4-diazacycloheptane)2](ClO4)2. Synthesis of 5,7-Dimethyl-1,4-diazacycloheptane and an Improved Synthesis of cis-Cyclohexane-1,3-diamine

2002 ◽  
Vol 55 (8) ◽  
pp. 523 ◽  
Author(s):  
V. P. Munk ◽  
S. T. Cham ◽  
R. R. Fenton ◽  
R. K. Hocking ◽  
T. W. Hambley
Keyword(s):  
Solid State ◽  
Molecular Mechanics ◽  
Crystal Structures ◽  
Van Der Waals ◽  
Monoclinic Space Group ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
R Value ◽  
Shed Light

The structures of three bis(diamine)nickel(II) complexes, chosen to shed light on the van der Waals radius of nickel(II), are described. [Ni(cis-1,3-chxn)2]Cl2 (cis-1,3-chxn = cis-cyclohexane-1,3-diamine) crystallizes in the monoclinic space group P21/n, with a 6.397(2), b 16.463(4), c 7.229(2) Å, b 90.70(2)�, and its structure has been refined to an R value of 0.031 on 1214F. [Ni{(R)-tmdz}2]Cl2�H2O (tmdz = 5,5,7-trimethyl-1,4-diazacycloheptane) crystallizes in the orthorhombic space group P212121, with a 10.678(1), b 11.073(5), c 17.968(6) Å, and its structure has been refined to an R value of 0.031 on 1586F. [Ni(dmdz)2](ClO4)2 (dmdz = 5,7-dimethyl-1,4-diaza- cycloheptane) crystallizes in the monoclinic space group P21/n, with a 9.582(1), b 10.390(2), c 11.817(3) Å, β 96.19(2)�, and its structure has been refined to an R value of 0.059 on 817F. In all three structures, short Ni���H and Ni���C interactions, ranging from 2.37 to 2.61 Å and 2.99 to 3.03 Å, respectively, are observed. Using molecular mechanics modelling to reproduce these separations, we have arrived at a van der Waals radius of 1.35 Å for low-spin nickel(ii). Analysis of Ni���O contacts in the solid state leads to a van der Waals radius of about 1.26 Å, which is consistent with the molecular mechanics derived value since these are usually longer.

Mono- and difunctional furan-based 1,2,3,5-dithiadiazolyl radicals; preparation and solid state structures of 2,5-[(S2N2C)OC4H2(CN2S2)] and 2,5-[(S2N2C)OC4H2(CN)]

1992 ◽  
Vol 70 (3) ◽  
pp. 919-925 ◽  
Author(s):  
A. Wallace Cordes ◽  
Charles M. Chamchoumis ◽  
Robin G. Hicks ◽  
Richard T. Oakley ◽  
Kelly M. Young ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Crystal Structures ◽  
Monoclinic Space Group ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
The Mean ◽  
Solid State Structures ◽  
Solid State Characterization

The preparation and solid state characterization of the bifunctional radical furan-2,5-bis(1,2,3,5-dithiadiazolyl) 2,5-[(S2N2C)OC4H2(CN2S2)] and the related monofunctional radical 2-cyanofuran-5-(1,2,3,5-dithiadiazolyl) 2,5-[(S2N2C)OC4H2(CN)] are described. The crystal structure of 2,5-[(S2N2C)OC4H2(CN2S2)] is orthorhombic, space group Pna21, and consists of interleaved arrays of dimers, for which the mean interannular [Formula: see text] contact is 3.137 Å. The crystal structure of the monofunctional radical 2,5-[(S2N2C)OC4H2(CN)] is monoclinic, space group P21/n, and consists of a ribbon-like network of dimers (mean interannular [Formula: see text] interconnected by close head-to-tail [Formula: see text] contacts. The dimer units form stacks parallel to z, with a mean interdimer [Formula: see text] separation of 3.956 Å. The similarities and differences between these two crystal structures and those of related benzene-substituted systems are discussed. Keywords: dithiadiazolyl radicals, furan-based diradicals, cyanofuran-based radicals, radical dimers, crystal structures.

The structures and energy minimization analyses of the macrotricyclic cage complex [Co(nosartacn)]3+ and its precursor [Co(taetacn)]3+

1983 ◽  
Vol 36 (12) ◽  
pp. 2359 ◽  
Author(s):  
SG Taylor ◽  
MR Snow ◽  
TW Hambley
Keyword(s):  
Solid State ◽  
Least Squares ◽  
Molecular Mechanics ◽  
Crystal Structures ◽  
Energy Minimization ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Cage Complex ◽  
R Factors ◽  
Tertiary Nitrogen

The crystal structures of (-)487-[Co(taetacn)] (ClO4)3 [taetacn = 1,4,7-tri(2-aminoethy1)-1,4,7-triazacyclononane] and (+)490-[Co(nosartacn)] (S2O6)3/2.4H2O (nosartacn = 9-nitro-1,4,7,11,14,19- hexaazatricyclo[7.7.4.24.14]docosane) have been determined. Crystals of the former complex (1) are cubic, space group P213, a 13.168(5) �, whereas the latter (2) are orthorhombic, space group C2221, a 10.22(1), b 6.944(8), c 32.33(1) �. The structures were refined by blocked-matrix least-squares methods to R factors of 0.040 and 0.050 on 952 and 2318 F respectively. The absolute configurations and conformations are described as Δ(λδ) for (1) and Λ(λδ) for (2). Molecular mechanics studies of conformers of both complexes show that the solid-state geometries are the most energetically favourable, and that other possible conformers are destabilized by coupling of the five-membered chelate rings through the tertiary nitrogen atoms.

The Dichloroplatinum(II) and Dichloropalladium(II) Complexes of 1,4-Diazacycloheptane: Preparative, Structural and Conformational Studies

1996 ◽  
Vol 49 (12) ◽  
pp. 1301 ◽  
Author(s):  
GW Allen ◽  
ECH Ling ◽  
LV Krippner ◽  
TW Hambley
Keyword(s):  
Crystal Structures ◽  
Chelate Ring ◽  
Chair Conformation ◽  
Monoclinic Space Group ◽  
Boat Conformation ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Membered Chelate Ring ◽  
Alternative Conformation

The preparation and purification of [Pt( hpip )Cl2] and [Pd( hpip )Cl2] ( hpip = homopiperazine = 1,4-diazacycloheptane) are described. Crystal structures of [Pt( hpip )Cl2] and [Pd( hpip )Cl2] have been determined by X-ray diffraction methods and refined to R values of 0.023 (932 F) and 0.023 (948 F). The crystals of [Pt( hpip )Cl2] are orthorhombic, space group Pbcm , a 7.7019(8), b 9.8080(12), c 12.1944(14) Ǻ, and those of [Pd( hpip )Cl2] are monoclinic, space group P21/m, a 6.1001(9), b 11.527(2), c 6.458(I) Ǻ, β 106.30(2)°. The seven- membered rings of the ligands in both complexes adopt boat-like conformations in which the five- membered chelate ring has an eclipsed N-C-C-N group and the six- membered chelate ring adopts a chair conformation. Molecular mechanics methods were used to investigate whether this conformation was a crystallographic artefact but it was found to be real. An alternative conformation in which the six-membered chelate ring adopts a skew-boat conformation was also investigated. It was found to be less stable than the conformation observed in the crystal structures, but to a degree that depends on whether non-bonded interactions involving the metal atom were included or not.

Strukturen der mehrkernigen nickelthiolato-komplexe [(μ-SMe)2(Ni(MeNHCS2))2] und cyclo-[(μ-SMe)2Ni]6 / Structures of Two Polynuclear Nickel-Thiolato-Complexes [(μ-SMe)2(Ni(MeNHCS2))2] and cyclo-[(μ-SMe)2Ni]6

1994 ◽  
Vol 49 (6) ◽  
pp. 770-772 ◽  
Author(s):  
Klaus Schulbert ◽  
Rainer Mattes
Keyword(s):  
Crystal Structures ◽  
Nickel Acetate ◽  
Monoclinic Space Group ◽  
Crystal Data ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Dithiocarbamic Acid ◽  
Coordination Spheres ◽  
Partial Degradation ◽  
Acid Esters

The reactions of N-substituted dithiocarbamic acid esters and nickel acetate yield, by partial degradation of the esters, the polynuclear nickel thiolato complexes cyclo-[(μ-SMe)2Ni]6, 1 and [(μ-SMe)2(Ni(MeNHCS2))2, 2. Their crystal structures have been determined. The Ni coordination spheres are comprised of four sulfur atoms in a planar arrangement. 1 is a second, highly symmetrical modification of the already known cyclic hexamer Ni6(SMe)12. In 2 two Ni(PhNHCS2) moieties are bridged to dimers by thiolato groups. Two of these dimers are connected to a tetramer by weak axial Ni-S interactions. Crystal data for 1: monoclinic, space group P21/n, a = 986.1(2), b = 1308.1(3), c = 1228.6(2) pm, β = 96.07(3)°, Z = 2, R = 0.072, Rw = 0.062, 3797 reflections. 2: orthorhombic, space group Pnma, a = 1790.0(4), b = 1806.7(4), c = 934.4(2) pm. Z = 4, R = 0.061, Rw = 0.051, 2079 reflections

scholarly journals Die Kristallstrukturen von (1,5-Ditolylpentaazadienido)(triphenylphosphan)gold(I) und 1,5-Ditolyl-3-methylpentaazadien / The Crystal Structures of (1,5-Ditolylpentaazadienido)(triphenylphosphane)gold(I) and 1,5-Ditolyl-3-methylpentaazadien

1988 ◽  
Vol 43 (10) ◽  
pp. 1219-1223 ◽  
Author(s):  
Johannes Beck
Keyword(s):  
Nitrogen Atom ◽  
Crystal Structures ◽  
Phosphorus Atom ◽  
Gold Atom ◽  
Monoclinic Space Group ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Lattice Constants ◽  
Monomeric Complex ◽  
Single Bonds

PPh3Au(tolN5tol) is obtained by the reaction of PPh3Au+ClO4- with Tl(tolN5tol). It crystallizes in the monoclinic space group P21/c with the lattice parameters a = 1548.8(5), b = 1070.7(2), c = 1779.1(3) pm, β = 90.33(2)°, Z = 4. In the monomeric complex the gold atom is nearly linearcoordinated by the phosphorus atom of the PPh3 group and nitrogen atom N3 of the pentaazadienido ligand ( N3 - Au - P 178.4°). tolNN(NCH3)NNtol crystallizes in the orthorhombic space group Pccn with the lattice constants a = 2426.7(9), b = 469.3(2), c = 1195.3(4) pm. The unit cell contains four molecules, located on twofold axes. Due to the isolobality of the CH3 and the PPh3Au group, the two structures are closely related. Both contain the typical planar zig-zag chain of five nitrogen atoms with located double bonds N1-N2 and N4 - N5 (from 119.8 to 126.6 pm) and shortened single bonds N2 - N3 and N3 - N4 (132.7 to 140.0 pm).

79Br, 127I NQR of Diammoniumalkyl Halides and Piperazinium Halides. Crystal Structure of Piperazinium Dibromide Monohydrate and Piperazinium Monoiodide

1989 ◽  
Vol 44 (1) ◽  
pp. 41-55 ◽  
Author(s):  
Jutta Hartmann ◽  
Shi-Qi Dou ◽  
Alarich Weiss
Keyword(s):  
Crystal Structure ◽  
Phase Transitions ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Monoclinic Space Group ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Temperature Range

Abstract The 79Br and 127I NQR spectra were investigated for 1,2-diammoniumethane dibromide, -diiodide, 1,3-diammoniumpropane dibromide, -diiodide, piperazinium dibromide monohydrate, and piperazinium monoiodide in the temperature range 77 ≦ T/K ≦ 420. Phase transitions could be observed for the three iodides. The temperatures for the phase transitions are: 400 K and 404 K for 1,2-diammoniumethane diiodide, 366 K for 1,3-diammoniumpropane diiodide, and 196 K for piperazinium monoiodide.The crystal structures were determined for the piperazinium compounds. Piperazinium dibromide monohydrate crystallizes monoclinic, space group C2/c, with a= 1148.7 pm, 0 = 590.5 pm, c= 1501.6pm, β = 118.18°, and Z = 4. For piperazinium monoiodide the orthorhombic space group Pmn 21 was found with a = 958.1 pm, b = 776.9 pm, c = 989.3 pm, Z = 4. Hydrogen bonds N - H ... X with X = Br, I were compared with literature data.

The Constituents of Marine Sponges. IX New Norditerpenoids from Aplysilla pallida

1997 ◽  
Vol 50 (9) ◽  
pp. 903 ◽  
Author(s):  
Trevor W. Hambley ◽  
Walter C. Taylor ◽  
Stephen Toth
Keyword(s):  
Crystal Structures ◽  
Spectroscopic Studies ◽  
Marine Sponges ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray

Four novel norditerpenoids were isolated from a new encrusting sponge, conveniently labelled Aplysilla pallida. The structures of aplypallidenone (1), aplypallidoxone (2), aplypallidione (3) and aplypallidioxone (4) were elucidated by spectroscopic studies and the crystal structures of aplypallidenone and aplypallidoxone have been determined by X-ray diffraction methods. The structure of (1) was refined to a residual of 0·040 for 1665 independent observed reflections and the structure of (2) was refined to a residual of 0·031 for 1699 independent observed reflections. The crystals of (1) are orthorhombic, space group P212121, a 7·728(2), b 10·838(4), c 24·880(5) Å, Z 4. Those of (2) are monoclinic, space group C 2, a 23·927(7), b 6·674(2), c 14·033(3) Å, Z 4.

Solid-state chemistry of polycarboxylate crown ether cation complexes: cooperative binding of water and metal ions by flexible chorands

1993 ◽  
Vol 71 (2) ◽  
pp. 239-253 ◽  
Author(s):  
Philip J. Dutton ◽  
Thomas M. Fyles ◽  
Valia Veettil Suresh ◽  
Frank R. Fronczek ◽  
Richard D. Gandour
Keyword(s):  
Solid State ◽  
Crown Ether ◽  
Sodium Salt ◽  
Metal Salt ◽  
Alkali Metal Salt ◽  
Cation Binding ◽  
Monoclinic Space Group ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Cesium Salt

The solid-state structures of alkali-metal salt complexes of crown ether tetra- and hexa-carboxylic acids (18C6A4 and 18C6A6) have been determined. The sodium salt of 18C6A6 crystallizes as the trihydrate in orthorhombic space group P212121 (a = 7.6868(12), b = 15.429(3), c = 21.975(2) Å, R = 0.031 for 5192 observed data); the potassium salt of 18C6A6 crystallizes as the the trihydrate in orthorhombic space group P212121 (a = 7.6711(8), b = 15.709(2), c = 21.966(5) Å, R = 0.035 for 2521 observed data); the thallium(I) salt of 18C6A6 crystallizes as the dihydrate in orthorhombic space group P212121 (a = 12.0331(10), b = 12.4333(12), c = 17.366(2) Å, R = 0.035 for 4952 observed data); and the cesium salt of 18C6A6 crystallizes as the dihydrate in monoclinic space group P21 (a = 7.708(3), b = 13.492(2), c = 11.9501(9) Å, β = 94.49(2)°, R = 0.029 for 4480 observed data). The sodium salt of 18C6A4 crystallizes as the dihydrate in monoclinic space group P21 (a = 11.4368(11), b = 7.7068(11), c = 12.6579(12) Å, β = 98.515(8)°, R = 0.035 for 3000 observed data); the thallium(I) salt of 18C6A4 crystallizes as the dihydrate in monoclinic space group P21(a = 11.719(2), b = 7.668(2), c = 12.8403(13) Å, β = 99.052(9)°, R = 0.040 for 3981 observed data); and the cesium salt of 18C6A4 crystallizes as the dihydrate in monoclinic space group P21 (a = 11.787(2), b = 7.637(2), c = 13.001(2) Å, β = 98.705(12)°, R = 0.038 for 3428 observed data). Both chorands exhibit a cooperative relationship of mean cavity radius and guest-ion radius, which closely follows the effective ionic radii of the guests. The hexaacid is a preorganized host for monohydrated cations. It provides a trigonal hydrogen bonding receptor site for the water molecule, and up to nine oxygen donors for cation binding. Guests ranging in size from Na+ to Cs+ are accommodated without distortion of the macrocyclic framework. The tetraacid is similarly tolerant of a range of guests, but greater structural reorganization of the ligand is required to optimize contacts with fully dehydrated cations. Skeletal drawings of donor atoms, in conjunction with polar coordinate maps of torsion angles, reveal how the demands of the guest are accommodated by the host.

Kristallstrukturen der iodierten closo-Hexaborate trans-(Ph4P)2[B6H4I2], mer-(Ph4P)2[B6H3I3] · 2 CH2Cl2, trans-(Ph4P)2[B6H2I4] · 2 CH3CN und (CH2Py2)[B6HI5]/Crystal Structures of the Iodized closo-Hexaborates trans-(Ph4P)2[B6H4I2], mer-(Ph4P)2[B6H3I3] · 2 CH2Cl2, trans-(Ph4P )2[B6H2I4] · 2 CH3CN and (CH2Py2)[B6HI5]

1998 ◽  
Vol 53 (2) ◽  
pp. 206-210 ◽  
Author(s):  
D. Sonnak ◽  
W. Preetz
Keyword(s):  
Single Crystals ◽  
Crystal Structures ◽  
Monoclinic Space Group ◽  
Orthorhombic Space Group ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
Structure Determinations

Abstract X-ray structure determinations have been performed on single crystals of trans-(Ph4P)2-[B6H4I2] (1) (triclinic, space group P1̄, a = 9.9680(12), b = 10.9690(11), c = 11.0470(14) Å,α = 88.167(9), β = 80.466(12), γ = 68.839(11)°, Z = 1), mer-(Ph4P)2[B6H3I3] · 2 CH2Cl2 (2)(triclinic, space group P1̄, a = 11.8694(11), b = 15.1699(13), c = 17.051(2) Å, α = 75.118(9), β = 71.953(10), γ = 69.331(8)°, Z = 2), trans-(Ph4P )2[B6H2I4] · 2 CH3CN (3) (monoclinic, space group P21/n, a = 14.9665(10), b = 7.6783(10), c = 23.385(3) Å, β = 95.78(9)°, Z = 2), and (CH2Py2)[B6HI5] (4) (orthorhombic, space group Pnma, a = 13.660(2), b = 11.8711(13), c = 13.839(2) Å, Z = 4). The B6 octahedra are compressed in the direction of the B-I bonds, resulting in shortened diagonal B ··· B distances with average values of the groups I-B ··· B-I = 2.37 and I-B ··· B-H = 2.43 Å as compared with H-B ··· B-H = 2.49 Å.

Crystal Structures of Cyclosporin Derivatives: O-Acetyl-(4R)-4-(E-2-butyl)-4,N-dimethyl-L-threonyl-cyclosporin A and O-Acetyl-(4R)-4-[E-2-(4-bromobutyl)]-4,N-dimethyl-L-threonyl-cyclosporin A

1999 ◽  
Vol 64 (1) ◽  
pp. 89-98 ◽  
Author(s):  
Bohumil Kratochvíl ◽  
Alexandr Jegorov ◽  
Svetlana Pakhomova ◽  
Michal Hušák ◽  
Petr Bulej ◽  
...  
Keyword(s):  
Solid State ◽  
Cyclosporin A ◽  
Crystal Structures ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray

The structures of O-acetyl-(4R)-4-(E-2-butyl)-4,N-dimethyl-L-threonyl-cyclosporin A (1) and O-acetyl-(4R)-4-[E-2-(4-bromobutyl)]-4,N-dimethyl-L-threonyl-cyclosporin A (2) were determined by X-ray diffraction methods and compared with the structure of related cyclosporins. In contrast to expectation, neither the acetylation nor the subsequent bromination of 1 affects the conformation and packing of cyclosporins in the solid state. Both compounds are isomorphous and crystallize in the orthorhombic space group P212121 with a = 12.936(2) Å, b = 15.590(2) Å, c = 36.280(3) Å, and a = 12.916(3) Å, b = 15.675(4) Å, c = 36.715(7) Å, for 1 and 2, respectively.

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