The synthesis, characterization and properties of alkyl complexes of the type [Cp*Fe(CO)2R] (Cp*=η5-C5(CH3)5; R=n-C3H7 to n-C12H25); the X-ray crystal and molecular structure of [Cp*Fe(CO)2(n-C5H11)] and molecular orbital and density functional calculations on the β-hydride elimination of [CpFe(CO)2(CH2CH3)]

1999 ◽  
Vol 587 (1) ◽  
pp. 28-37 ◽  
Author(s):  
R.Oliver Hill ◽  
Charles F. Marais ◽  
John R. Moss ◽  
Kevin J. Naidoo
1984 ◽  
Vol 62 (9) ◽  
pp. 1822-1827 ◽  
Author(s):  
Clifford G. Marcellus ◽  
Richard T. Oakley ◽  
A. Wallace Cordes ◽  
William T. Pennington

Protonation of the trisulphur trinitride ion, S3N3−, with tetrafluoroboric acid yields the ring-contracted S-amino thiodithiazyl salt, S3N2NH2+BF4−. The crystal and molecular structure of this salt has been determined by X-ray diffraction. The crystals are triclinic, space group P1, with a = 5.445(2), b = 7.346(3), c = 9.473(5) Å, α = 85.89(4), β = 83.92(3), γ = 82.13(3)°, V = 372.6(4) Å3, Dc = 2.02 g cm−3, and Z = 2. The structure was solved by direct methods and refined by full-matrix least-squares procedures to give a final R = 0.060. The structure of the five-membered ring with a single exocyclic NH2 group bonded to sulphur is discussed in relation to other S3N2NR derivatives. The reasons for the instability of six-membered rings of the type S3N3R are discussed in the light of MNDO molecular orbital calculations on an S3N3H model.


1996 ◽  
Vol 51 (12) ◽  
pp. 1771-1778 ◽  
Author(s):  
Jere T. Koskinen ◽  
Mikko Koskinen ◽  
Ilpo Mutikainen ◽  
Berit Mannfors ◽  
Hannu Elo

The crystal and molecular structure of aminoguanidine monohydrochloride, CN4H7+.CL- in which aminonoguanidine exists in the monocation form, was determined by single-crystal X-ray diffraction. The structure of the monocation is largely similar to that of aminoguanidine dication as present in previously studied divalent salts. The monocation was found to exist in the form of the tautom er that allows strong resonance in the guanyl group. As compared to the dication, the terminal hydrazine nitrogen atom bears one hydrogen atom less. The monocation is planar, the only atoms deviating from the plane being the hydrogens attached to the terminal hydrazine nitrogen. Quantum chemical calculations on the endiamine tautomer of aminoguanidine free base as well as on aminoguanidine monocation and dication were also perform ed by using the HF and MP2 ab initio methods and also the B3- LYP and B-LYP methods based on density functional theory. On the basis of the calculations, a predicted structure of the endiamine tautom er of aminoguanidine free base is presented


1999 ◽  
Vol 54 (12) ◽  
pp. 1529-1531 ◽  
Author(s):  
Alexander Jockisch ◽  
Hubert Schmidbaur

The molecular structure of tris(dimethylarsino)amine has been determined by X-ray diffraction methods. The compound has a planar AS3N core unit with a paddle-wheel conformation of the three Me2As groups. This structure was also confirmed by density functional calculations.


1981 ◽  
Vol 46 (1) ◽  
pp. 6-19 ◽  
Author(s):  
Viktor Kettman ◽  
Ján Garaj ◽  
Jaroslav Majer

The crystal and molecular structure of [Cr(S2CN(CH2)5)3].2 CHCl3 was found by the X-ray structural analysis method. The value R 0.090 was found for 1 131 observed independent reflections. The substance crystallizes in a space group of symmetry P212121 with the following unit cell dimensions: a = 0.8675 (6), b = 1.815(2), c = 2.155(3) nm. The experimentally observed crustal density was 1.48 Mgm-3 and the value calculated for Z = 4 was 1.51 Mgm-3. The CrS6 coordination polyhedron has the shape of a trigonally distorted octahedron, where the D3 symmetry is a approximately retained. The degree of trigonal distortion expressed as the projection of the chelate S-Cr-S angle onto the plane perpendicular to the C3 pseudo axis is Φ = 41.7° (Φ = 60° for an octahedron). The skeleton of the structure formed by the complex molecules contains channels filled with chloroform molecules. The specific type of complex-chloroform interaction consists of the formation of hydrogen bonds of the chloroform protons with the fully occupied pπ-orbitals of the sulphur atoms in the coordination polyhedra. The low stability and crystal decomposition can be explained by loss of chloroform from the channels.


Author(s):  
Shabana Noor ◽  
Richard Goddard ◽  
Fehmeeda Khatoon ◽  
Sarvendra Kumar ◽  
Rüdiger W. Seidel

AbstractSynthesis and structural characterization of two heterodinuclear ZnII-LnIII complexes with the formula [ZnLn(HL)(µ-OAc)(NO3)2(H2O)x(MeOH)1-x]NO3 · n H2O · n MeOH [Ln = Pr (1), Nd (2)] and the crystal and molecular structure of [ZnNd(HL)(µ-OAc)(NO3)2(H2O)] [ZnNd(HL)(OAc)(NO3)2(H2O)](NO3)2 · n H2O · n MeOH (3) are reported. The asymmetrical compartmental ligand (E)-2-(1-(2-((2-hydroxy-3-methoxybenzylidene)amino)-ethyl)imidazolidin-2-yl)-6-methoxyphenol (H2L) is formed from N1,N3-bis(3-methoxysalicylidene)diethylenetriamine (H2valdien) through intramolecular aminal formation, resulting in a peripheral imidazoline ring. The structures of 1–3 were revealed by X-ray crystallography. The smaller ZnII ion occupies the inner N2O2 compartment of the ligand, whereas the larger and more oxophilic LnIII ions are found in the outer O2O2’ site. Graphic Abstract Synthesis and structural characterization of two heterodinuclear ZnII-LnIII complexes (Ln = Pr, Nd) bearing an asymmetrical compartmental ligand formed in situ from N1,N3-bis(3-methoxysalicylidene)diethylenetriamine (H2valdien) through intramolecular aminal formation are reported.


2011 ◽  
Vol 34 (5-6) ◽  
pp. 127-130 ◽  
Author(s):  
Yaya Sow ◽  
Libasse Diop ◽  
Kieran C. Molloy ◽  
Gabrielle Kociok-Köhn

Abstract The title compounds [R2NH2][C2O4SnMe3](R=i-Bu, Cy), in which tin atoms adopt a distorted trigonal bipyramidal configuration, have been prepared and submitted to an X-ray diffraction study. These compounds have been obtained from the reaction of (Cy2NH2)2C2O4·H2O or (i-Bu2NH2)2C2O4 with SnMe3Cl. In both [R2NH2][C2O4SnMe3] compounds, the trans complex has an almost regular trigonal bipyramidal geometry around the tin atom. The SnMe3 residues are connected as a chain with bridging oxalate anions in a trans-SnC3O2 framework, the oxygen atoms being in axial positions. The cations connect linear adjacent chains through NH…O hydrogen bonds giving layered structures.


1979 ◽  
Vol 34 (1) ◽  
pp. 48-51 ◽  
Author(s):  
Jürgen Kopf ◽  
Klaus von Deuten ◽  
Bahman Nakhdjavan ◽  
Günter Klar

Abstract The structure of 2,8-dimethyldibenzo[c,g][1,2,5,6]tetrathiaocin (1b) has been determined by X-ray methods and discussed in connection with the preferred conformations of diaryl disulfides. The compound has the anti-form I. The SS-distance is 205.8 pm, the mean CSS-angle 104.1°, and the CSS/SSC-dihedral angle 111.1°.


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