Chromotropism of coordination compounds and its applications in solution

Studies on mixed chelates—III: Mixed copper(II) chelates with N,N,N′,N′-tetramethylethylenediamine and β-diketones[1]

Vapor- and gas-responsive ionic liquids (ILs) comprised of cationic metal-chelate complexes and bis(trifluoromethanesulfonyl)imide (Tf(2)N) have been prepared, namely, [Cu(acac)(BuMe(3)en)][Tf(2)N] (1 a), [Cu(Bu-acac)(BuMe(3)en)][Tf(2)N] (1 b), [Cu(C(12)-acac)(Me(4)en)][Tf(2)N] (1 c), [Cu(acac)(Me(4)en)][Tf(2)N] (1 d), and [Ni(acac)(BuMe(3)en)][Tf(2)N] (2 a) (acac = acetylacetonate, Bu-acac = 3-butyl-2,4-pentanedionate, C(12)-acac = 3-dodecyl-2,4-pentanedionate, BuMe(3)en = N-butyl-N,N',N'-tetramethylethylenediamine, and Me(4)en = N,N,N',N'-trimethylethylenediamine). These ILs exhibited reversible changes in color, thermal properties, and magnetic properties in response to organic vapors and gases. The Cu(II)-containing ILs are purple and turn blue-purple to green when exposed to organic vapors, such as acetonitrile, methanol, and DMSO, or ammonia gas. The color change is based on the coordination of the vapor molecules to the cation, and the resultant colors depend on the coordination strength (donor number, DN) of the vapor molecules. The vapor absorption caused changes in the melting points and viscosities, leading to alteration in the phase behaviors. The IL with a long alkyl chain (1 d) transitioned from a purple solid to a brown liquid at its melting point. The Ni(II)-containing IL (2 a) is a dark red diamagnetic liquid, which turned into a green paramagnetic liquid by absorbing vapors with high DN. Based on the equilibrium shift from four- to six-coordinated species, the liquid exhibited thermochromism and temperature-dependent magnetic susceptibility after absorbing methanol.

Vapochromic ionic liquids from metal-chelate complexes exhibiting reversible changes in color, thermal, and magnetic properties.

Two series of new mixed-ligand nitronyl nitroxide Ni(II) complexes of [Ni(β-diketonato)2(NIT2-py)] and [Ni(β-diketonato)(tmen)(NIT2-py)]+ types with various kinds of β-diketonates have been synthesized and structurally and magnetically characterized, where NIT2-py is 2-(2-pyridyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazolyl-1-oxyl 3-oxide and tmen is N,N,N ‘,N ‘-tetramethylethylenediamine. The X-ray structural analysis for three tmen complexes with 2,4-pentanedionate (1b), 1,3-diphenyl-1,3-propanedionate (2b), and 4,4,4-trifluoro-1-phenyl-1,3-butanedionate (5b) demonstrated that the β-diketonato complexes assume a mer (cis,trans) N3O3 geometrical configuration. The structural parameters are as follows:  1b (C23H39F6N5NiPO4·1/3CH2Cl2), trigonal, R3, a = 33.299(5) A, c = 15.007(9) A, Z = 18; 2b (C28H41F6N5NiPO4), orthorhombic, Pbca, a = 23.732(6) A, b = 18.504(5) A, c = 15.345(4) A, Z = 8; 5b (C28H38F9N5NiPO4), triclinic, P1, a = 12.068(2) A, b = 16.942(2) A, c = 9.161(1) A, α = 105.26(1)°, β = 103.72(1...

Synthesis, Magnetic Properties, and Electronic Spectra of Octahedral Mixed-Ligand (β-Diketonato)nickel(II) Complexes with a Chelated Nitronyl Nitroxide Radical.

Fukuda Y

Papers

混合キレート II N,N,N’,N’-テトラメチルエチレンジアミンとβ-ジケトンの混合ニッケル(II)キレート