Hisashi Okawa

Binuclear metal complexes. XXVI. Synthesis and magnetic and spectral properties of binuclear copper(II) complexes with N-(2-alkylthioethyl)-3-aminopropanol☆

Abstract Binuclear copper(II) complexes with N-(2-alkylthioethyl)-3-aminopropanol [Cu(RS(CH 2 ) 2 NH(CH 2 )O)]ClO 4 and Cu(RS(CH 2 ) 2 NH(CH 2 ) 3 O)CuBr 2 (where R = CH 3 , C 2 H 5 , n-C 3 H 7 , n-C 3 H 7 , n-C 4 H 9 , t-C 4 H 9 ), were prepared and characterized by elemental analyses, infrared and electronic spectra, and magnetic susceptibilities (78–300 K). Similar to binuclear complexes with the NNO tridentate ligands (R 2 (CH 2 ) m NH(CH 2 ) n OH = R-nnoH), [Cu(R-nno)]X (X = ClO4 or B(C 6 H 5 ) 4 ), all these complexes show subnormal magnetic moments at room temperature and exhibit a band in the near-ultraviolet region (∼24 × 10 3 cm −1 ) characteristic of oxobridged structures. In the case of the perchlorates, the cryomagnetic data can be interpreted by the equation based on a binuclear structure, and the antiferromagnetic interaction is generally stronger than that of the [Cu(R-nno)]X complexes. However, the temperature dependences of magnetic susceptibilities of the Cu(R-sno)CuBr 2 complexes are unusual and could not be explained by any conventional theoretical formulas.

Binuclear metal complexes. XX[1]. Antiferromagnetic spin-exchange interaction in copper(II)-nickel(II) and copper(II)-cobalt(II) hetero-metal complexes with 3-formylsalicylic acid-diamine schiff bases [2]

Abstract Copper(II)-nickel(II) hetero-metal binuclear complexes, CuNi(fsapn)·2H2O, CuNi(fsach)·2H2O and CuNi(fsaph)·5H2O, and copper(II)-cobalt(II) complexes, CuCo(fsapn)·2H2O, CuCo(fsabn)·2H2O and CuCo(fsaph)·2H2O, have been synthesized and characterized, where H4fspn, H4fsabn, H4fsach and H4fsaph denote Schiff bases obtained by condensing 3-formylsalicylic acid with propylenediamine, 2,3-butanediamine, 1,2-cyclohexanediamine and o-phenylenediamine, respectively. Based on cryomagnetic measurements, it was found that a considerable antiferromagnetic spin-exchange interaction is operating between the metal ions except for CuNi(fsaph). 5H2O and CuCo(fsaph)·2H2O, the magnetisms being interpreted in terms of the Heisenberg model. The magnetisms of CuNi(fsaph)·5H2O and CuCo(fsaph)·2H2O obeyed the Curie law and the Curie-Weiss law respectively.

Synthesis and properties of iron(III) complexes with N,N′-disalicylideneethylenediamine and a bidentate ligand

Iron(III) mixed-chelates of the type Fe(salen)(ab) (H2salen=N,N′-disalicylideneethylenediamine; Hab=acetylacetone(Hacac), benzoylacetone(Hbzac), salicylaldehyde(Hsal), 8-quinoline(Hoxin), L-alanine(LalaH), L-valine(L-valH) or L-phenylalanine(L-pheH) have been prepared and characterized. The complexes have a cis-β-octahedral structure in solid state. Electronic spectra of Fe(salen)(acac) and Fe(salen)(bzac) in dichloromethane and those of all of the complexes in methanol were dependent on concentration. Spectral and conductivity measurements revealed that the complexes are in an equilibrium, nFe(salen)(ab)⇋Fe(salen)′+ab− n. Judging from the CD spectra and analogy to Co(salen)(ab) (ab=L-amino acidate ions), the Λ-cis-β(fac) isomer was preferentially formed in the case of the complexes with L-amino acids.

Synthesis and characterization of imidazolate-bridged iron(III)-copper(II) and manganese(III)-copper(II) binuclear complexes

Imidazolate-bridged iron(III)–copper(II) and manganese(III)–copper(II) binuclear complexes [FeL1CuL2][BPh4](1) and [MnL1CuL2][BPh4](2) have been prepared and characterized, where H2L1 is 4-methyl-N,N′-bis(salicylidene)-4-azaheptane-1,7-diamine and H2L2 denotes the unsymmetrical quadridentate ligand 4-(6-methyl-8-oxo-2,5-diazanona-1,5-dienyl)imidazole. The magnetic susceptibility data indicated that the spin ground states of the complexes (1) and (2) are S= 2 and respectively, which are produced by antiferromagnetic interaction operating between high-spin iron(III)S1=5//2[manganese(III)S1= 2] and copper(II)S2=½ ions through the L2 imidazolate group. The Mossbauer spectrum of (1) measured at 4.2 K showed a doublet with Δ= 1.30 mm s–1 and δd= 0.49 mm s–1, consistent with high-spin iron(III). The e.s.r. spectrum of a powdered sample of complex (1) measured at 20 K showed no signals, while that of (2) showed several signals.