Hiro Kuma

STRUCTURES AND PROPERTIES OF TERNARY COPPER(II) COMPLEXES WITH 4,5-DIHYDROXYPHENYLALANINE OR 2,4,5-TRIHYDROXYPHENYLALANINE AND AROMATIC DIAMINES

Abstract Structural and spectroscopic studies were carried out on ternary Cu(II) complexes, Cu(DA)(AA), with tyrosine derivatives having hydroxyl substituents (AA = 4,5-dihydroxyphenylalanine (dopa) or 2,4,5-trihydroxyphenylalanine (topa)) and aromatic diamines (DA = 2,2′-bipyridine (bpy) or 1,10-phenanthroline (phen)). The charge transfer (CT) absorption bands observed as difference absorption spectra in the near-UV region indicate an effective stacking interaction between DA and the side-chain aromatic ring of AA in the ternary Cu(II) complexes. Three complexes, [Cu( dl -topa)(bpy)(H 2 O)] + (complex 1 ), [Cu( l -dopa)(phen)] + [Cu( l -dopa)(CH 3 CH 2 CH 2 OH)(phen)] + (complex 2 ), and [Cu( dl -dopa)(bpy)] + (complex 3 ), were isolated as single crystals, and their structures were determined by X-ray analysis. The central Cu(II) ions in complexes 1 and 3 have square-pyramidal and square-planar geometries respectively. Complex 2 contains two independent molecules having each of the two geometries. All the molecular structures reveal intramolecular aromatic ring stacking between DA and AA in correspondence with the solution spectral observations. The stacking with the topa ring having three hydroxyl groups was found to be slightly stronger than that with the dopa ring having two hydroxyl groups, which is consistent with the more intense CT absorption bands of the topa complex compared with the dopa complex in aqueous solution. Moreover, the oxidative deamination of benzylamine with the ternary Cu(II) complex containing dopa or topa was investigated under aerobic conditions.

Synthesis and characterization of the platinum complexes with N,S or C,N,S ligands derived from 2-phenylbenzothiazoline

Abstract The preparation of the two platinum complexes, the thiolato-bridged tetranuclear [Pt4(phbt)4] and the neutral dithiolene-like-non-innocent mononuclear [Pt(ddbt)], is described. [Pt4(phbt)4] · 2CH2ClCH2Cl crystallizes in the monoclinic space group P21/n, with a = 19.893(5), b = 17.950(7), c = 14.844(4) A, β = 93.69(2)°, V = 5289(3) A3 and Z = 4. [Pt(ddbt)] crystallizes in the monoclinic space group P21/n, with a = 10.789(9), b = 24.56(2), c = 8.64(1) A, β = 102.69(8)°, V = 2232(4) A3 and Z = 4.

Synthesis and properties of yttrium(III) complexes with N-substituted salicylideneimines

Abstract The reaction of yttrium(III) chloride hydrate with N-alkylsalicylideneimines (abbreviated as (Sal-R)H) has yielded yttrium(III) complexes of the type YCl 3 {(Sal-R)H)} 3 . In these complexes, the Schiff bases in their neutral forms are bound with yttrium(III) ion. Their properties are presented and possible structures are discussed.

Synthesis and properties of tetrakisbridged parallel- and cross-orientation biphenylophanes

Abstract The two isomers of tetrakisbridged dimethoxybiphenylophanes, 1 and 2, have been synthesized. With respect to the longest wavelength absorption bands due to the biphenyl chromophores, the cross-orientation isomer exhibited the marked bathochromic shift, while the parallel-orientation isomer the typical exciton splitting. Their transannular properties in solution were further confirmed by X-ray crystal analysis.

Synthesis of Lanthanide (III) Complexes with N-t-Butylsalicylideneiminate

Abstract Lanthanide(III) complexes with N-t-butylsalicylideneiminate (abbreviated as H-SAL.t-C4H9) have been synthesized as yellow crystals by the reaction of several lanthanide(III) chloride hydrates and the Schiff base. The complexes obtained, which were purified by recrys tallization from appropriate organic solvents, are represented by the formula In(H-SAL. t-C4H9)3.3H2O, where the notation Ln denotes tervalent La, Pr, Nd, Gd, Yb, and Lu.

Rotamers of the 1-phenylethylamine ligand in trans- bis(imidato)bis(1-phenylethylamine)copper(II) complexes, where imidato = 3,3-dimethylglutarimidato, hydantoinato and succinimidato ligands

Abstract Three [CuN4] complexes, red trans-[Cu(3,3-dmgluim)2(R-phenea)2] (1), blue-violet trans-[Cu(hyd)2(R-phenea)2] (2) and blue trans-[Cu(succim)2(S-phenea) (R-phenea)] (3) (3,3-dmgluim=3,3-dimethylglutarimidato, hyd=hydantoinato, succim = succinimidato, phenea = 1-phenylethylamine), were prepared and their crystal structures were determined. Crystal data are as follows: 1 is monoclinic, space group P21, a = 14.854(1), b = 17.105(3), c-5.988(2) A, β=91.65(1)°, U=1520.8(5) A3, Z=2, R=0.033, and 2318 reflections; 2 is monoclinic, space group P21, a = 19.946(2), b = 6.035(1), c = 10.025(1) A,β= 104.383(7)°, U= 1168.9(3) A3, Z=2, R =0.035, and 1864 reflections; 3 is triclinic, space group P 1 , a = 12.434(4), b = 12.670(3), c = 8.765(2) A, α=94.83(2), β= 112.87(2) γ=73.15(2)°, U= 1219.9(6) A3, Z=2, R=0.054, and 3678 reflections. In 1 the coordination geometry is planar, and the specific intermolecular hydrogen bonds are formed along the c axis between H(NH2) of phenea and O(CO) of the six- membered cyclic imidate. In 2 and 3 the coordination geometries are tetrahedrally distorted. The intramolecular hydrogen bonds are formed between H(NH2) of phenea and O(CO) of the five-membered cyclic imidate. Three different staggered forms of and one eclipsed form of rotamers in the phenea ligands have been found.

A Novel Triad of Isomeric Forms of bis(N-Phenyl-5-chloro-salicylideneaminato)copper(II)

Abstract Three isomeric forms of Cu(5-Cl-sal-Ph)2 have been isolated in crystals, where 5-Cl-sal-Ph denotes N-phenyl-5-chloro-salicylideneaminate. The structures of the three forms(1, 2 and 3) have been determined by the single crystal X-ray diffraction method, which has revealed that Forms 1, 2 and 3 having the identical chemical composition differ only in the molecular structure. This is the first triad of isomeric forms of Cu(X-sal-R)2 that has been established with certainty, where X and R denote substituents on the benzene nucleus and on the nitrogen atom, respectively. The molecular structure in Form 1 is perfectly planar trans-tetra-coordinated, Form 2 is dinuclear with distorted square-pyramidal penta-coordination about copper(II) and the structure in Form 3 is distorted-planar cis-tetra-coordinated. Form 3 is the first cis-tetra-coordinated complex of Cu(X-sal-R)2 that has been confirmed by the X-ray method.

Synthesis and Characterization of Cobalt(III) Complexes with N-Hydroxy-N′-(2-alkylaminoethyl)-2,3-butanediimines and the Corresponding 2-Phenylaminoethyl Compound

Abstract Cobalt(III) complexes with N-hydroxy-N′- (2-alkylaminoethyl)-2,3-butanediimines and the corresponding 2-phenylaminoethyl compound (Hdox-enR; R=Me, Et and Ph) have been studied. Compounds of the type Co(dox-enR)2X have been obtained (X=Cl, Br, I, NO3, and ClO4) in crystals. Mainly on the basis of electronic absorption spectra and magnetic properties, it is concluded that they are hexa-coordinate cobalt(III) complexes of a spin-paired type, in which the ligands are bound, in their deprotonated anionic form, to the cobalt(III) ion. The ligands function as terdente ligands, the secondary amino-group also being involved in the bonding with the cobalt(III) ion.

Synthesis and properties of nickel(II) complexes with Schiff bases obtained from pyridoxal and amines

Abstract Cobalt(II) and cobalt(III) complexes have been synthesized with Schiff bases obtained from pyridoxal and monoamines (RNH2) and diamines. The 1:2 type cobalt(II) complexes were obtained with bidentate Schiff bases R = iso-C3H7, t-C4H9 cyclohexyl and p-tolyl. Electronic absorption spectra and magnetic data show that they have a tetrahedral configuration. The octahedral 1:3 type cobalt(III) complexes were obtained with the bidentates for R = CH3, C2H5, n-C3H7, iso-C3H7 and p-tolyl. With quadridentate Schiff bases derived from ethylenediamine and 1-methylethylenediamine (propylenediamine) as an amine component, 1:1 type cobalt(II) complexes were obtained in crystals. They consists of low-spin square-planar cobalt(II) complexes, their electronic spectra being very similar to that of the “active form” of N,N′-ethylenebis(salicylaldiminato)cobalt(II).

Formation of a nickel(II) complex with a new N2S2 macrocyclic ligand by C–Cl bond cleavage and C–S bond formation

Heating a monohelical square-planar nickel(II) complex containing chlorine atoms in the side arms gives a distorted octahedral nickel(II) complex containing the trans-N2S2 macrocyclic ligand by carbon–chlorine bond cleavage and carbon–sulfur bond formation.