Dithiolium and diselenolium compounds of the transition metals

1969 ◽  
Vol 22 (1) ◽  
pp. 83 ◽  
Author(s):  
RL Martin ◽  
IM Stewart

The preparations are reported of an extended series of compounds of the type ML2X4 where M is Mn, Fe, Co, or Ni; X is Cl or Br; and L is analytically identical with dithioacetylacetone. ��� Electronic, infrared, and Mossbauer spectra together with the temperature dependence of the magnetism (80-300�K) of these compounds establish-contrary to previous suggestions in the literature-that they should be properly formulated as tetrahalometallate salts of the 3,5- dimethyl-1,2-dithiolium cation. Simple salts of this cation (such as the iodide) have also been isolated. ��� During the course of this work salts (I- and [CoCl4]2-) of the hitherto unknown 3,5-dimethyl-1,2-diselenolium ion were synthesized and characterized for the first time.

1990 ◽  
Vol 2 (50) ◽  
pp. 10091-10107 ◽  
Author(s):  
J M Fiddy ◽  
I Hall ◽  
F Grandjean ◽  
G J Long ◽  
U Russo

1978 ◽  
Vol 31 (3) ◽  
pp. 487 ◽  
Author(s):  
RL Martin ◽  
IAG Roos ◽  
DML Goodgame ◽  
AASC Machado

Mossbauer spectra of a number of compounds containing the [Fe(pyb)3]2+ complex cation [pyb, 2-(2'-pyridyl)benzimidazole] confirm that these compounds undergo a change of spin state with temperature consistent with a 5T2-1A1 spin crossover. The nature of the Mossbauer spectra and their temperature-dependence are sensitive to the associated anion and the method of preparation. ��� The temperature-dependence of the Mossbauer parameters has been used to derive information about the distortions from octahedral symmetry and it is concluded that the dimensions of the crystal-line lattice are changing slightly with temperature.


1971 ◽  
Vol 24 (11) ◽  
pp. 2231 ◽  
Author(s):  
RL Martin ◽  
IAG Roos

The temperature dependence of the Mossbauer spectra of some iron- containing compounds of dithioacetylacetone are reported between 4 and 293 K. ��� The quadrupole splitting ΔEq of [Fe(SacSac)3] is larger than usually observed for low-spin six-coordinated iron(III) and is ascribed to the lifting of orbital degeneracy of the 2T2 ground state by small axial and rhombic distortions. ��� The unsubstituted and phenyl-substituted dithiolium salts of [FeCl4]2- exhibit strongly temperature-dependent quadrupole splittings, which arise directly from the lifting of the orbital degeneracy of the 5E ground state due to distortion of the [FeCl4]2- tetrahedron.


2002 ◽  
Vol 57 (6-7) ◽  
pp. 627-630 ◽  
Author(s):  
Takashi Suzuki ◽  
Noriaki Okubo

The Mössbauer effect in the low-dimensional compound Fe1.33Nb2.67Se10 has been examined between 78 and 414 K. An anusual positive temperature dependence of the quadrupole splittings was found above 250 K. As a possible origin a mechanism due to π bonding is suggested


1973 ◽  
Vol 51 (11) ◽  
pp. 1697-1703 ◽  
Author(s):  
D. R. Fisher ◽  
D. Sutton

Fe(CO)3(PPh3)2 reacts with p-substituted aryl diazonium tetrafluoroborates to yield the compounds [Fe(CO)2(PPh3)2(N2C6H4X)]BF4 (where X = F, Cl, Br, H, NO2, OCH3, and OH but not NEt2). The complex cation displays properties consistent with replacement of an equatorial CO ligand in Fe(CO)3(PPh3)2 by the more effective π-acceptor ligand [N2C6H4X]+ analogous to NO+. A very strong band at ca. 1720 cm−1 in the i.r. spectrum due to v(N2) has been identified by 15N isotopic substitution. This value is much higher than for most other arylazo complexes yet prepared and the azo group resists catalytic hydrogenation. A number of spectroscopic measurements are reported, including unusually small quadrupole splitting effects in the Mössbauer spectra.


1976 ◽  
Vol 54 (5) ◽  
pp. 711-717 ◽  
Author(s):  
R. G. Goel ◽  
H. S. Prasad ◽  
G. M. Bancroft ◽  
T. K. Sham

Dimethyltin chromate and basic dimethyltin and diphenyltin carbonates have been isolated for the first time. Structural features of these compounds, as well as of the previously known basic dimethyltin chromate, have been investigated by examining their infrared, Raman, and Mössbauer spectra. Infrared, Raman, and Mössbauer spectra of [Me2Sn(NCS)]2O have also been examined, and by comparing its spectroscopic data with those for (Me2Sn)2OCrO4, (Me2Sn)2OCO3, and (Ph2Sn)2O(CO3), possible structures have been suggested for the latter compounds. From the combined infrared and Mössbauer data, a structure is also proposed for Me2SnCrO4. All compounds are indicated to have polymeric structures with bridging CrO42− or CO32−.


1975 ◽  
Vol 30 (12) ◽  
pp. 1627-1632 ◽  
Author(s):  
F. Schmidt ◽  
W. Gunsser ◽  
A. Knappwost

Abstract Iron clusters have been prepared within zeolite holes by reduction of zeolites containing ferrous ions. The diameter of these particles must therefore be smaller than 13 Å. They are super-paramagnetic and their Mössbauer spectra show no HFS, even at 4 K.The temperature dependence of the magnetic susceptibility of the unreduced zeolites obeys a Curie-Weiss law with peff = 4,54 μB and Θ = 105 K. The Weiss curves of the reduced samples lie distinctly below those of the bulk material.


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