Magnetism, electronic spectra, and structure of transition metal alkoxides. VI. Chromium(III) chloro alkoxides

1968 ◽  
Vol 21 (6) ◽  
pp. 1461 ◽  
Author(s):  
L Dubicki ◽  
GA Kakos ◽  
G Winter
Keyword(s):  
Transition Metal ◽  
Electronic Spectra ◽  
Metal Alkoxides ◽  
Compound A ◽  
Tetrameric Structure

In the compound Cr(OMe)C12,2CH3OH one molecule of methanol can be replaced by one molecule of acetone, acetonitrile, or dioxan. The magnetism and spectra are interpreted in terms of dimeric models. On heating the dimethanolate one molecule of methanol is lost and for this compound a tetrameric structure is proposed.

Magnetism, electronic spectra, and structure of transition metal alkoxides. I. methoxides and ethoxides of chromium(II), manganese(II), Iron(II), cobalt(II), nickel(II), copper(II), titanium(III), chromium(III), and iron(III)

1966 ◽  
Vol 19 (2) ◽  
pp. 207 ◽  
Author(s):  
RW Adams ◽  
E Bishop ◽  
RL Martin ◽  
G Winter
Keyword(s):  
Transition Metal ◽  
Spectral Data ◽  
Electronic Spectra ◽  
Magnetic Moments ◽  
Field Parameter ◽  
Ligand Field ◽  
Metal Alkoxides ◽  
Infinite Lattices ◽  
Ligand Field Parameter

The magnetic moments and electronic spectra are reported for the following divalent transition metal methoxides: Cr(OCH3)2, Mn(OCH3)2, Fe(OCH3)2, Co(OCH3)2, Ni(OCH3)2, and Cu(OCH3)2. These measurements when coupled with the involatility and insolubility of the compounds favour structures based on infinite lattices composed either of regular (Mn, Fe, Co, and Ni) or distorted (Cr and Cu) MO6 octahedra. The spectral data place the ligand field parameter, Δ, for the methoxide group very close to that of water.

Magnetism, electronic spectra, and structure of transition metal alkoxides. IX. Vanadium(III)chloromethoxides

1970 ◽  
Vol 23 (1) ◽  
pp. 15 ◽  
Author(s):  
GA Kakos ◽  
G Winter
Keyword(s):  
Transition Metal ◽  
Electronic Spectra ◽  
Metal Alkoxides ◽  
Infinite Lattice ◽  
Physical Measurements ◽  
Solvent Molecules ◽  
Tetrameric Form

The compounds VCl(Ome2 (1), VCl(OMe)2,MeCOMe (2), VCl(OMe)2,MeOH (3), and VCl2(OMe),2MeOH (4) were prepared. From magnetic and other physical measurements it is concluded that in (1) the vanadium atoms form trimeric clusters which associate through chlorine bridges to form an infinite lattice. Similar basic units are proposed for (2), but separated from each other by solvent molecules. Two forms of (3) were isolated from the same solution; a soluble trimeric form (A) for which a structure similar to that of (2) is suggested, and an insoluble tetrameric form (B) where the vanadium atoms are situated at the corners of a rhombus. For (4) a structure involving three octahedra, sharing corners (methoxy bridges), is suggested.

Magnetism, electronic spectra, and structure of transition metal alkoxides IV. cobalt(II) methoxy halides

1967 ◽  
Vol 20 (11) ◽  
pp. 2343 ◽  
Author(s):  
GA Kakos ◽  
G Winter
Keyword(s):  
Transition Metal ◽  
Electronic Spectra ◽  
Metal Alkoxides

The series Co(OMe)X where X = Cl, Br, and I have been prepared and their magnetism and electronic spectra examined. The results clearly show the effect of increasing ligand size on the stereochemistry of the alkoxide. Whereas Co(OMe)I appears to be octahedral and unable to solvate, Co(OMe)Br is tetrahedral but is capable of solvation by methanol to form an octahedral species. Co(OMe)I is tetrahedral and apparently incapable of solvation.

Magnetism, electronic spectra, and structure of transition metal alkoxides. VIII. Nickel halo methoxides

1970 ◽  
Vol 23 (1) ◽  
pp. 1 ◽  
Author(s):  
AG Krueger ◽  
G Winter
Keyword(s):  
Transition Metal ◽  
Electronic Spectra ◽  
Metal Alkoxides ◽  
Antiferromagnetic Exchange ◽  
Magnetic Clusters ◽  
Spectral Measurements ◽  
Infinite Lattice

The results of magnetic and spectral measurements of Ni(OMe)Cl and its solvates are interpreted in terms of clusters of four nickel atoms interacting ferromagnetically through 90� methoxy bridges. It is proposed that these clusters associate through chlorine bridges to form an infinite lattice. Solvation by methanol breaks only chlorine bridges so that the magnetic clusters are preserved. Stepwise replacement of chlorine by methoxyl resulted in the isolation of the expected compounds of composition Ni3(OMe)4Cl2 and Ni3(OMe)5Cl. Here, the magnetic isolation of the clusters disturbed by antiferromagnetic intercluster exchange. Bromine and iodine bridges also promote antiferromagnetic exchange but in contrast to the methoxy bridges, they may be broken by solvation with methanol.

Magnetism, electronic spectra, and structure of transition metal alkoxides. V. Copper(II) methoxides

1967 ◽  
Vol 20 (11) ◽  
pp. 2351 ◽  
Author(s):  
RW Adams ◽  
CG Barraclough ◽  
RL Martin ◽  
G Winter
Keyword(s):  
Transition Metal ◽  
Electronic Spectra ◽  
Metal Alkoxides ◽  
Kcal Mole

Najor differences in magnetism are observed in the series CuXL where X = -OMe, Cl, Br, and L = -OMe, acac. Cu(OMe), exhibits linear antiferro- magnetism, CuCl(OMe) follows the Curie law with μeff 2.0 B.M., and CuBr(OMe) is only feebly paramagnetic. The magnetism of Cu(OMe) acac may be interpreted in terms of a singlet-triplet equilibrium with -J = 725 cm-1 (2.08 kcal mole-1).

Vibrational and electronic spectra and bonding in ionic transition metal hexacarbonyls

1969 ◽  
Vol 30 (1-3) ◽  
pp. 29-50 ◽  
Author(s):  
E.W. Abel ◽  
R.A.N. McLean ◽  
S.P. Tyfield ◽  
P.S. Braterman ◽  
A.P. Walker ◽  
...  
Keyword(s):  
Transition Metal ◽  
Electronic Spectra ◽  
Ionic Transition ◽  
Metal Hexacarbonyls

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.

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