Bennett Hutchinson

Far-infrared spectra of some Fe(1,10-phenanthroline) 2X2 complexes

Abstract The far-i.r. spectra of Fe(1,10-phenanthroline)2X2 complexes (XCl−, Br−, N−3, NCO−, OAc−, CNO− and CN−) have been measured in the 600–140 cm−1 region. The metal—ligand stretching vibrations are dependent on the spin state of Fe(II). For the high-spin complexes (XCl−, Br−, N−3, NCO−, OAc−) the FN(phen) stretches are found at ∼225 cm−1 and the FeX stretches in the 325–180 cm−1 region. For the low-spin complexes (XCN−, CNO−) the FeN(phen) stretches are found at 350–395 cm−1 and the FeX stretches at 520–540 cm−1. The FeCN stretch in K4FeCN6 is assigned at 588 cm−1. The ligand bands are also altered by spin state change. Significant vibrational coupling is found when XCN−.

Metal—nitrogen stretching assignments in some metallophthalocyanines and μ-oxo-(Fephthalocyanine)2

Abstract Metal-isotope substitution has been employed to establish the absorptions in the i.r. spectra of some metallophthalocyanines that contain MN stretching motion. The primary MN stretching bands appear at 240.7 cm−1 in 64Znpc; 284.0 cm−1 in 63Cupc; 376.0 cm−1 and 317.8 cm−1 in 58Nipc; and 308.4 cm−1 in 54Fepc. Assignment of the far-i.r. spectrum of u-oxo-(Fepc)2 places the FeN stretching band at 280.2 cm−1 and suggests a linear arrangement of the FeOFe with Fe atoms in the plane of the phthalocyanine ring.

Structural and vibrational characteristics of the tetrasulfatodimolybdenum ions with MoMo bond orders of 3.5 and 4.0

Abstract The compound K 4 [Mo 2 (SO 4 ) 4 ]Br·4H 2 O has been made and its crystal structure determined. Space group P 4/ mnc ; unit cell dimensions, a = 11.903(2), c = 8.021(1) A, V = 1136(1) A 3 . The compound is isomorphous with the analogous chloride whose structure has been reported. The MoMo and MoBr distances are 2.169(2) and 2.926(1) A, respectively and the [Mo 2 (SO 4 ) 4 ] 3− ions reside on crystallographic special positions with 4/ m symmetry. The Raman spectra of both the bromo and chloro compounds have been measured and the MoMo stretching frequency is 370 ± 1.5 cm −1 in each, for the compounds containing the natural isotopic distribution of molybdenum. The chloro compound has been prepared containing the pure isotope 92 Mo as well, and the Raman spectra recorded. The v (MoMo) band is shifted by 6.8 ± 0.5 cm −1 . The compound K 4 [Mo 2 (SO 4 ) 4 ]·2H 2 O has also been prepared with Mo at natural abundance and with the pure isotope 100 Mo, whereby a shift of 8.5 ± 0.5 cm −1 was found. These and other results will be discussed with regard to the similarity of the Raman spectra of the Mo 2 (S0 4 ) 4 3− and M0 2 (S0 4 ) 4 4− species.

Effect of changing oxidation state on the metal–ligand vibrations of [Cr(2,2′-bipyridyl)3]n+ type complexes

In the series of tris-(2,2′-bipyridyl) complexes of chromium, the Cr–N stretching frequencies change very little by changing the oxidation state of chromium from III to 0, this unexpected result indicating that the strength of the Cr–N bond does not change appreciably over a wide change in the oxidation state of chromium.

The preparation and characterization of transition metal complexes of cyclic hydroxamic acids

Abstract Several cyclic hydroxamic acid complexes with first row transition metals have been synthesized. The coordination properties of the ligands 1-hydroxy-2-indolinone (HI) and 3-amino-3,4-dihydro-1-hydroxy-carbostyril (HADC) have been investigated using spectral, magnetic, and X-ray powder diffraction measurements. The results indicate that oligomeric species are formed by both ligands with Co(II), Ni(II), and Cu(II). Structures are proposed for these complexes with both ligands and for Fe(III) and Zn(II) with HI.

A comparison of three assignment techniques for metal-ligand stretching bands—a low-frequency infrared study of some transition metal bis,- tris- and tetrakis-tropolonato complexes

Abstract The low-frequency infrared spectra (600-150 cm −1 ) of several bis- and tris- transition metal tropolonates were measured and the metal-oxygen stretching bands assigned based on the metal-isotope substitution method. Since other assignment methods for these complexes have placed the metal-oxygen stretching bands more than 300 cm −1 higher, the differences were discussed. Eight-coordinate tropolonato complexes were also investigated in the far-infrared region and MO stretching assignments for these complexes presented.

A low-frequency infrared study of the dodecahedral complexes [M(1,8-naphthyridine)4](ClO4)2 and K4[M(oxalate)4]

Abstract The low-frequency infrared spectra of two series of eight-coordinate dodecahedral complexes [M(1,8-naphthyridine) 4 ](ClO 4 ) 2 and K 4 [M(oxalate) 4 ] · 5H 2 O are assigned using the metal-isotope substitution technique.

Characterization of a High Temperature Spin Equilibrium Compound, Bis[hydrotris(pyrazol-1-yl)borate]iron(II)

Variable temperature magnetic susceptibility, Mossbauer, and far-i.r. spectral data are correlated to show that bis[hydrotris(pyrazol-1-yl)borate]iron(II) exhibits a low-spin, high-spin crossover at high temperature.

A low frequency infrared study of tetranitratometallates of manganese(II), iron(III), cobalt(II), nickel(II) and zinc(II)

Abstract The low-frequency i.r. spectra of five first row transition metal dodecahedral eight-coordinate tetranitrato complexes were measured from 500-50 cm−1. The metal—oxygen stretching bands were assigned between 260 and 310 cm−1 and their position related to their oxidation state and crystal field stabilization energy.