Kazuo Nakamoto

Infrared and Raman spectra of inorganic and coordination compounds

Inorganic molecules (ions) and ligands are classified into diatomic, triatomic, four-atomic, five-atomic, six-atomic, and seven-atomic types, and their normal modes of vibration are illustrated and the corresponding vibrational frequencies are listed for each type. Molecules of other types are grouped into compounds of boron, carbon, silicon, nitrogen, phosphorus, and sulfur, and the structures and infrared (IR)/Raman spectra of select examples are shown for each group. Group frequency charts including band assignments are shown for phosphorus and sulfur compounds. Other group frequency charts include hydrogen stretching frequencies, halogen stretching frequencies, oxygen stretching and bending frequencies, inorganic ions, and metal complexes containing simple coordinating ligands. Keywords: inorganic compounds; coordination compounds; diatomic molecules (ligands); triatomic molecules (ligands); four-atomic molecules (ligands); five-atomic molecules (ligands); six-atomic molecules (ligands); seven-atomic molecules (ligands); boron compounds; carbon compounds; silicon compounds; nitrogen compounds; phosphorus compounds; sulfur compounds; group frequency charts

Infrared Spectra and Normal Coordinate Analysis of Metalloporphins

The infrared spectra of porphin and its metal complexes with 64Zn, 68Zn, Cu, and Ni have been obtained from 4000 to 100 cm−1. Normal coordinate analyses have been carried out on the D4h model of the porphin complexes with 64Zn, 68Zn, Cu, and Ni. Only the eighteen in‐plane vibrations have been calculated. The results indicate that the bands between 1700 and 950 cm−1 are due to CC stretching, CN stretching, CH in‐plane bending, CCN in‐plane bending or coupled vibrations between these modes, and that the largest contribution of the metal‐nitrogen stretching coordinate is found in the vibrations at ≈ 203, 246, and 295 cm−1 of the Zn, Cu, and Ni complexes, respectively. The Urey‐Bradley force constants for the corresponding metal‐nitrogen stretching modes are estimated to be 0.553, 0.662, and 0.760 mdyn/A, respectively.

Metal isotope effect on metal-ligand vibrations—XII: Imidazole complexes with Co(II), Ni(II), Cu(II) and Zn(II)☆

Abstract Far-i.r. spectra of sixteen imidazole (HIm) complexes with Co(II), Ni(II), Cu(II) and Zn(II) have been measured. Metal-ligand stretching bands have been assigned based on observed metal isotope shifts. Approximate normal coordinate analyses have been carried out on the Zn(HIm)2X2 series (X = Cl, Br and I).

Resonance Raman spectra and biological significance of high-valent iron(IV,V) porphyrins

Abstract Extensive research in the past decades has shown that nature relies on high-valent iron (IV,V) porphyrins in a number of enzyme-directed processes of heme proteins. For example, hydroxylation reaction catalyzed by cytochrome P450 involves an iron porphyrin intermediate which contains the oxoferryl moiety (Fe(IV)O). Liver microsomal cytochrome P450-LM 3,4 is known to catalyze the transfer of a functionalized nitrogen atom intra- as well as inter-molecularly, and the proposed reaction cycle presumably involves a high-valent iron porphyrin intermediate which contains the nitrido-iron moiety(Fe(V)N). This review is focused on the biological significance of these high-valent iron(IV,V) porphyrins and their Fe(IV)O and Fe(V)N stretching vibrations observed in resonance Raman spectra.

Structure sensitive bands in the vibrational spectra of metal complexes of tetraphenylporphine

Abstract The i.r. and RR spectra of twenty Fe(TPP)LL′ type complexes have been measured to locate structure-sensitive bands. In i.r. spectra, band I (1350-1330 cm −1 ) and band III (469-432 cm −1 ) are spin-state sensitive whereas band II (806-790 cm −1 ) is oxidation-state sensitive and slightly spin-state sensitive in the Fe(II) state. To examine the nature of these bands, the i.r. spectra of Co(TPP), (Fe(TPP)) 2 O and their d 8 and d 20 analogs have been measured, and empirical assignments proposed. In RR spectra, band C (1545-1498 cm −1 , ap) and band D (1565-1540 cm −1 , p) are spin-state sensitive whereas band E (391-376 cm −1 , p) is sensitive to both spin and oxidation states. These results on RR spectra are in good agreement with those of previous workers.

Vibrational spectra and normal coordinate analysis of bis(glycino) complexes with Ni(II), Cu(II) and Co(II)

Abstract The i.r. and Raman spectra of bis(glycino) complexes of Ni(II), Cu(II) and Co(II) are reported. In order to aid band assignments, isotope substitutions such as H/D, 14 N/ 15 N, 58 Ni/ 62 Ni and 63 Cu/ 65 Cu have been carried out. Normal coordinate analyses on trans-bis(glycino) complexes of Ni(II) and Cu(II) have been made based on these data. The results provide definitive band assignments of the metal—nitrogen and metal—oxygen stretching modes which have been controversial.

Metal isotope effect on metal-ligand vibrations—VIII: Far-infrared and Raman spectra of zinc halide complexes of pyridine

Abstract The far-infrared and Raman spectra of the Zn(pyridine) 2 X 2 ( X = Cl, Br or I) type complexes have been measured. Band assignments have been made based on isotope shifts due to the 64 Zn- 68 Zn and pyridine-pyridine( d 5 ) substitutions.

Vibrational spectra of transition metal complexes of tetraphenylporphine

Abstract The far i.r. spectra of tetraphenylporphine complexes of Pd(II), Co(II), Cu(II), Ag(II) and Zn(II) have been obtained. In order to aid in the assignment of the metal-nitrogen vibrations the metal isotope technique has been applied to the Ni, Cu, and Zn complexes. Vibrations containing contributions from the metal-nitrogen stretching coordinate have been assigned based on these metal isotope data and the results of a normal coordinate analysis of Zn(II)-porphine. The variation of the frequencies of the major bands is shown to be dependent upon the number of d electrons and is explained on the basis of ligand field stabilization energy.

Far-infrared spectra of mercaptoalkylamine complexes with NiII and PdII☆

Abstract The far-infrared spectra of metal complexes of mercaptoethylamine and related ligands with Ni II and Pd II have been measured. Band assignments have been made based on isotope substitution of the metal ( 58 Ni 62 Ni or 104 Pd 110 Pd) and the amino group (NH 2 ND 2 ) of the ligand. The configuration of theMN 2 S 2 skeleton has been determined by the observed number of the MN and MS stretching bands. The electronic spectra of the Ni II complexes support the structures proposed by the far-infrared study.

Infrared and raman spectra of bis(imidotetraphenyldithiodiphosphino-S,S′) complexes with Cu(II), Co(II) and Fe(II)d

The infrared and Raman spectra of KL, FeL2, CoL2 and CuL2 (L = imidotetraphenyldithiodiphosphino anion) have been obtained in the range from 1600-200 cm−1. To assign the chelate ring vibrations of CuL2 resonance Raman spectra have been measured as a function of the exciting frequency. The CuS stretching vibration (F2) of the tetrahedral CuS4 core has been located at 292-283 cm−1 based on the 63Cu-65 Cu isotope shift observed in the far-infrared spectra. The totally symmetric CuS stretching vibration (A1) appears strongly at 206 cm−1 in the Raman spectrum. These results have been utilized to assign the spectra of the remaining compounds.