Structural and spectroscopic studies of transition metal nitrite complexes. III. Crystal structures and spectra of Aquabis(meso-1,2-diphenylethane-1,2-diamine)-nitronickel(II) perchlorate and Bis(meso-1,2-diphenylethane-1,2-diamine)-(nitrito-O,O')nickel(II) chloride

1981 ◽  
Vol 34 (10) ◽  
pp. 2069 ◽  
Author(s):  
AJ Finney ◽  
MA Hitchman ◽  
CL Raston ◽  
GL Rowbottom ◽  
AH White
Keyword(s):  
Fine Structure ◽  
Water Molecule ◽  
Single Crystals ◽  
Electronic Spectra ◽  
Spectroscopic Studies ◽  
Molecular Structures ◽  
Nitrite Ion ◽  
Nickel Ion ◽  
Crystal And Molecular Structures ◽  
Coordinated Water

The crystal and molecular structures of the complexes [Ni(mstien),(NO2)(H2O)] ClO4 and [Ni(mstien)2(O2N)] Cl are reported (mstien = meso-stilbenediamine, 1,2-diphenylethane-1,2-di-amine). Both compounds contain nickel(II) in an essentially octahedral ligand environment. In the latter complex, the nitrite ion chelates, while in the former it is present as a nitro group situated trans to a coordinated water molecule. In both complexes the conformations observed for the amine chelate rings can be rationalized on the basis that they minimize intramolecular ligand repulsions. The complex [Ni(mstien)2(O2N)] NO2 is isomorphous with the analogous chloride compound, and spectral evidence suggests that the complex [Ni(mstien)2(O2N)] ClO4 also contains a chelating nitrite group. The electronic spectra of single crystals of [Ni(mstien),(O2N)] X (X = Cl- and NO2-) show bands centred at c. 25000 cm-l which exhibit vibrational fine structure. The energies of the progressional spacings are c.600cm-l, which suggests that the bands are probably due to n → π* internal nitrite transitions. The band centred at c. 20500 cm-1 in [Ni(mstien)2(NO2)(H2O)] ClO4 also shows well resolved vibrational fine structure with a progressional spacing of c. 630 cm-1. This implies that the band is not due to a 'd-d' transition, but must be caused by the excitation of an electron into the nitrite π* orbital, either from a non-bonding nitrite orbital, or more probably from the nickel ion.

Structural and spectroscopic studies of transition metal nitrite complexes. V. Crystal structures and spectra of trans-Tetrakis(pyridine)dinitritonickel(II)-pyridine (1/2), trans-Tetrakis(4-methylpyridine)dinitritonickel(II) and trans-Tetrakis(pyrazole)-dinitritonickel(II)

1981 ◽  
Vol 34 (10) ◽  
pp. 2095 ◽  
Author(s):  
AJ Finney ◽  
MA Hitchman ◽  
CL Raston ◽  
GL Rowbottom ◽  
BW Skelton ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Transition Metal ◽  
Crystal Structures ◽  
Electronic Spectra ◽  
Spectroscopic Studies ◽  
Molecular Structures ◽  
Aromatic Rings ◽  
Paddle Wheel ◽  
Crystal And Molecular Structures ◽  
Infrared Frequencies

The crystal and molecular structures of the compounds [Ni(py)4(ONO)2],2py, [Ni(γmpy),(ONO)2] and [Ni(prz)4(ONO)2] are reported.�All three are trans nitrito complexes, the pyridine (py) compound containing two pyridine molecules of solvation. The aromatic rings in the first two complexes adopt 'paddle wheel' conformations with pitch angles varying between 40 and 70�. The nitrite ions are positioned so as to minimize repulsive interactions with the amines, and it seems likely that these groups bond through oxygen rather than nitrogen because this allows a lesser degree of interligand steric interference. The amine rings in [Ni(prz)4(ONO)2] are orthogonal to the plane containing the nickel and coordinated pyrazole nitrogen atoms; the nitrito groups are disordered between two inequivalent positions, each of which involves hydrogen bonding with the pyrazole NH groups. The nitrite infrared frequencies are similar to those observed for other nickel(II) nitrito complexes except that the antisymmetric NO stretching mode of one of the groups in the pyrazole complex is much lower in energy than expected, being in the range normally associated with a nitrogen-bonded or chelated nitrite group. It is suggested that this deviation may be caused by the hydrogen bonding in the complex. The electronic spectra of the compounds yield 10Dq values of 9100 and 8500 cm-1 for the nitrite ligands in [Ni(py)4(ONO)2] and Ni(prz)4(ONO)2], respectively, placing the nitrito group towards the weaker end of the spectro-chemical series.

The electronic spectra of coordinated nitrite ion: correlation between spectra and structure

1980 ◽  
Vol 58 (8) ◽  
pp. 823-832 ◽  
Author(s):  
Ian M. Walker ◽  
A. B. P. Lever ◽  
Paul J. McCarthy
Keyword(s):  
Fine Structure ◽  
Metal Ions ◽  
Single Crystals ◽  
Electronic Spectrum ◽  
Electronic Spectra ◽  
Electronic Transition ◽  
Structure Elucidation ◽  
Nickel Complexes ◽  
Nitrite Ion ◽  
Oxygen Atoms

The characteristic electronic spectrum of the nitrite ion survives when the ion is bonded to metal ions through the oxygen atoms. The vibrational fine structure associated with the n → π* electronic transition in the near uv region has been examined at 10 K in single crystals of K3[Hg(O2N)4](NO3) and in a series of nickel complexes with N-alkylated ethylenediamines. When either non-coordinated, monodentate oxygen coordinating, or bidentate chelating through oxygen, nitrite ion in the crystals shows vibronic features which depend on nitrite environment. It is suggested that the electronic spectra of the nitrite ion may constitute a useful tool in structure elucidation.

Structural and spectroscopic studies of transition metal nitrite complexes. VIII. Crystal structures and spectra of three pentanuclear species with stoichiometry [Ni5(N-substituted ethane-1,2-diamine)4(OH)2(NO2)8]

1981 ◽  
Vol 34 (10) ◽  
pp. 2139 ◽  
Author(s):  
AJ Finney ◽  
MA Hitchman ◽  
CL Raston ◽  
GL Rowbottom ◽  
AH White
Keyword(s):  
Transition Metal ◽  
Crystal Structures ◽  
General Formula ◽  
Infrared Spectra ◽  
Spectroscopic Studies ◽  
Molecular Structures ◽  
Structural Variations ◽  
Crystal And Molecular Structures

The preparation of a series of novel compounds of general formula [Ni5L4(NO2)8(OH)2] formed by ethane-1,2-diamine or one of five N-substituted ethane-1,2-diamines (L) is described. The crystal and molecular structures of the ethane-1,2-diamine, N,N'-diethylethane-1,2-diamine and N,N-dimethylethane-1,2-diamine complexes are reported. Each compound contains a planar, pentameric arrangement of nickel(II) ions, linked by bridging hydroxide and nitrite ligands. The details of the nitrite bridges differ among the complexes, causing differences in their electronic and infrared spectra. The structural variations are probably caused by the differing steric requirements of the amine substituents.

Experimental and computational structural study of two hindered aminoanthraquinones in crystals and solutions

2000 ◽  
Vol 215 (9) ◽  
Author(s):  
A.V. Yatsenko ◽  
K.A. Paseshnichenko ◽  
S.I. Popov
Keyword(s):  
Solid State ◽  
Single Crystal ◽  
Electronic Spectra ◽  
Molecular Structures ◽  
Amino Group ◽  
Single Crystal Diffraction ◽  
Molecular Conformations ◽  
X Ray ◽  
Crystal And Molecular Structures ◽  
Visible Spectra

The crystal and molecular structures of 2-methyl-1-methylamino-anthraquinone (I) and 1-methylphenylamino-anthraquinone (II) were studied by the X-ray single-crystal diffraction and the visible spectra of crystalline specimens and their solutions were recorded. The molecule I is closely planar, whereas in the molecule II the amino group is 58° rotated out of the plane of the anthraquinone skeleton. In both structures the molecules pack in stacks. The comparison of experimental and calculated (on the DFT and AM1 levels) molecular structures, together with the comparison of experimental and INDO/S-calculated electronic spectra, give the evidence that molecular conformations (especially for II) change upon transfer from the solid state to solutions, and the π-delocalisation throughout the whole molecule enhances in the solid state.

Photorearrangement of 2-cyanobicyclo[2.2.1]hept-2-ene. Observation of 1,2- and 1,3-sigmatropic shifts

1982 ◽  
Vol 60 (13) ◽  
pp. 1657-1663 ◽  
Author(s):  
Ikbal A. Akhtar ◽  
John J. McCullough ◽  
Susan Vaitekunas ◽  
Romolo Faggiani ◽  
Colin J. L. Lock
Keyword(s):  
Single Crystals ◽  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
Major Product ◽  
Molecular Structures ◽  
Lithium Aluminum ◽  
Mercury Vapour ◽  
X Ray ◽  
Crystal And Molecular Structures ◽  
Mercury Vapour Lamp

Irradiation of 2-cyanobicyclo[2.2.1]hept-2-ene (2-cyanonorbornene, 4) in hexane, with the full arc of a mercury vapour lamp, gives the rearrangement products 1-cyanobicyclo[4.1.0]hept-2-ene 5 and 7-cyanotricyclo[4.1.0.03.7]heptane 6 in the ratio 20:1. These products were separated by preparative vpc. The structure of the major product 5 was determined by single crystal X-ray analysis. Reduction of 5 with lithium aluminum hydride gave the corresponding primary amine, which was converted to the p-bromobenzenesulfonamide 9, mp 150–151 °C, which gave single crystals from ethanol–water. The crystal and molecular structures are described. The minor product 6 was hydrogenated to give 7-cyanobicyclo[2.2. 1]heptane. Formation of 5 and 6 may involve concerted σ2s + π2s and σ2a + π2a processes respectively, which are photochemically allowed.

Silver(I) Phenoxyalkanoates: The Crystal and Molecular-Structures of catena-[Bis-μ-(phenoxyacetato-O,O')-disilver(I)] and Bis[bis-μ-(4-fluoro-phenoxyacetato-O,O')-bis{aquasilver(I)}]

1990 ◽  
Vol 43 (10) ◽  
pp. 1707 ◽  
Author(s):  
G Smith ◽  
DS Sagatys ◽  
CA Campbell ◽  
DE Lynch ◽  
CHL Kennard
Keyword(s):  
Experimental Data ◽  
Water Molecule ◽  
Crystal Structures ◽  
Molecular Structures ◽  
Phenoxyacetic Acid ◽  
Crystal And Molecular Structures ◽  
Silver Atoms

The crystal structures of the silver(I) complexes with phenoxyacetic acid and 4-fluorophenoxyacetic acid, catena-[ bis-μ-(phenoxyacetato-O,O′)- disiver (I)] (1) and bis [ bis-μ(4-fluorophenoxyacetato-O,O′)-{ aquasilver (I)}] (2) have been determined and refined to residuals R 0.068 and 0.036 respectively for 1783 and 2549 observed reflections. Both structures are based on similar bis ( carboxylato -O,O′) bridged dimers with Ag-Ag 2.866(2)Ǻ (1) and 2.836(2)Ǻ (2). However, (1) forms a step polymer through terminal oxygens [Ag-O 2.417, 2.443(9)Ǻ], while (2) is a discrete centrosymmetric tetramer with a water molecule on each of the four silver atoms [Ag- Ow 2.499(4)Ǻ], and an Ag-O bridge distance of 2.498(4)Ǻ. This results in triangular coordination about one silver and tetrahedral about the second. Experimental data indicate that anhydrous silver(I) 4-chlorophenoxyacetate (3) is similar to complex (1).

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