The Heterotrimetallic Complex [Ni(acacen)KLa(pta)4]: Structural and Thermochemical Studies

Abstract

The heterotrimetallic species [Ni(acacen)KLa(pta)4] [H2acacen and Hpta being N,N′‐ethylenebis(acetylacetonimine) and 1,1,1‐trifluoro‐5,5‐dimethyl‐2,4‐hexanedione, respectively] was obtained by interaction of Ni(acacen) with KLa(pta)4 in chloroform. From the X‐ray, single crystal structure determination, the potassium cation acts as a bridge between the complex anion [La(pta)4]− and the neutral complex Ni(acacen). Sublimation, thermal behaviour, pressure, and composition of the vapour phase have been investigated for both [Ni(acacen)KLa(pta)4] and the parent complexes Ni(acacen) and KLa(pta)4, by means of thermal analysis and mass spectrometry using a Knudsen cell. The heterotrimetallic molecule was not found in the saturated vapour. Two processes take place upon heating: [Ni(acacen)KLa(pta)4](s) → [KLa(pta)4](s) + Ni(acacen)(g) and [KLa(pta)4](s) → [KLa(pta)4](g). The standard free energy of formation for [Ni(acacen)KLa(pta)4] have been estimated (ΔGf0 380K = −6.1±2 kJ/mol). [Ni(acacen)KLa(pta)4] can be sublimed completely at low pressure because both parent complexes KLa(pta)4 and Ni(acacen) are volatile.

Sublimable chloroquinolinate lanthanoid single-ion magnets deposited on ferromagnetic electrodes

“…We should point out the fact that, although rare, other thermally stable sublimable ionic molecules based on mononuclear lanthanoid complexes are known. Among them, the tetrakis–diketonato complexes of the type M[Ln(dik) 4 ] where M = Cs, Y and La 42 – 44 stand out, since some of these molecules have been used in the fabrication of nano-optical devices by thermal techniques under high vacuum conditions. 45 These compounds are non-hygroscopic and air-stable and can be sublimed on substrates maintaining their molecular structure.…”

The use of 3d-metal complexes as ligands to prepare volatile 4f–3d heterobimetallic complexes

“…A new series of heterobimetallic complexes, [M(acacen)Ln(dik) 3 ] (Ln = La, Gd; M = Ni, Cu; dik = hfa, pta), were prepared [1,14]. In the crystal structures of compounds [M(acacen) Ln(dik) 3 ] (Hdik = Hpta, hfa) (Fig.…”

“…In all the structures of the new series of heterobimetallic complexes [M(SB)Ln(dik)3 ], the complexes M(SB) act as neutral ligands[1,[12][13][14]. The rare earth elements are chelated by four pairs of oxygen atoms from three dik(-) ligands and one M(SB) complex.…”

Mass spectrometric study of the vaporization of N,N′-o-phenylene-bis(salicylideniminate) nickel(II), copper(II), and zinc(II) and N,N′-ethylene-bis(salicylaldiminate) zinc(II) complexes

“…Even though complexes of metals with Schiff bases belong to a class of compounds rather well investigated by various methods, the thermodynam ics of vaporization and the composition of the gas phase have been studied only for complexes of nickel with Н 2 асасеn bases: N,N' ethylene bis(acetylacetonimine) and Н 2 salen: N,N' ethyl ene bis(salicylaldimine), Ni(acacen) and Ni(salen), respectively [13,14]. The saturated vapor above these compounds was found to be composed of monomer molecules only.…”

“…Of the two complexes, Ni(acacen) was found to be the most volatile. The authors of [14] sug gested that the lower volatility of the Ni(salen) com plex was associated with the presence of [Ni(salen)] 2 dimers in crystal lattice [15]; these dimers are formed as a result of stacking interactions occurring between aromatic fragments of mononuclear molecules. The transition of such monomer Ni(salen) molecules to the gas phase is accompanied by the decomposition of the abovementioned dimers.…”