Magneto-structural variety of new 3d–4f–4(5)d heterotrimetallic complexes

Abstract

Three families of heterotrimetallic chains (type 1-type 3), with different topologies, have been obtained by reacting the 3d-4f complexes, [{Cu(L(1))}xLn(NO3)3] with x = 1 or 2, formed in situ by the reaction of Schiff-base bi-compartmental [Cu(II)(L(1))] complexes and lanthanide(iii) salts, with (NHBu3)3[M(CN)8] (M = Mo(V), W(V)). For type 1 series of compounds, 1-D coordination polymers, with the general formula [{Cu2(valpn)2Ln}{M(CN)8}]·nH2O·mCH3CN (where H2valpn = 1,3-propanediylbis(2-iminomethylene-6-methoxy-phenol), result from the association of trinuclear {CuLn(III)} moieties and [M(V)(CN)8](3-) anions acting as tri-connecting spacers [Ln = La (1), Ce (2), Eu (3), Tb (4), Ho (5), M = Mo; Ln = Tb (6), Ho (7), M = W; m = 0, n = 1.5 (7) and 2 (1-4, 6); n = 1, m = 1 (5)]. The type 2 family has the general formula [{Cu(valdp)Ln(H2O)4}{M(CN)8}]·2H2O·CH3CN (where H2valdp = 1,2-propanediylbis(2-iminomethylene-6-methoxy-phenol)) and also consists of heterotrimetallic chains involving binuclear {Cu(II)Ln(III)} units linked to [M(CN)8](3-) anions coordinating through two cyano groups [Ln = Gd (8), Tb (9), Dy (10); M = Mo; Ln = La (11), Gd (12), Tb (13), Dy (14); M = W]. With large Ln(III) ions (La(III) and Pr(III)), the type 3 family of heterotrimetallic compounds are assembled: [{Cu2(valdp)2Ln(H2O)4}{Mo(CN)8}]·nCH3OH·mCH3CN, n, m = 0, Ln = La (15); n = m = 1, Pr (16), in which the trinuclear {CuLn(III)} nodes are connected to [Mo(V)(CN)8](3-) anions that act as tetra-connecting spacers. For Tb(III) derivatives of the type 1 (compounds 4 and 6), the DC magnetic properties indicate a predominant ferromagnetic Cu(II)-Tb(III) interaction, while the AC magnetic susceptibility (in the presence of a static magnetic field, HDC = 3000 Oe) emphasize the slow relaxation of the magnetization (Ueff/kB = 20.55 K and τ0 = 5.5 × 10(-7) s for compound 4, Ueff/kBT = 15.1 K and τ0 = 1.5 × 10(-7) s for compound 6). A predominant ferromagnetic Cu(II)-Ln(III) interaction was also observed in the type 2 series (compounds 8-10 and 12-14) as a result of the magnetic coupling between copper(ii) and lanthanide(iii) ions via the phenoxo-bridge. The magnetic behavior for the La(III) derivatives reveals that weak ferromagnetic interactions are also operative between the Cu(II) and the 4d/5d centers.

Structures for the 3d–5d–4f Heterotrimetallic Complexes: Synthesis, Structures, and Magnetic Properties

“…The bond lengths and angles found for complex 3 are all in the normal range expected for these types of complexes. [4d], [4r], [4s], [4t], As for the [W(CN) 8 ] 3– anion in 3 , the structural parameters are also similar to those in complexes 1 and 2 except for the different connection mode; that is the bridged mode for 1 and 2 but terminal fashion for 3 . For the packing structures of 3 , the coordination water molecules and terminal cyanide nitrogen atoms give rise to a rich network of hydrogen bond contacts.…”

Syntheses, Crystal Structures, and Magnetic Properties of Two Cyanide‐Bridged Bimetallic Magnetic Chains based on Octacyanomolybdate(V) and Lanthanide(III)

“…The asymmetric unit contains a [Eu(tmphen) 2 Figure 1, the coordination sphere of Eu atoms 3+ units in cisoid mode to form a chain structure, whereas the other CϵN groups are terminal, analysed by Continuous Shape Measure. [14] The bond lengths for Mo-CN range from 2.143(6) to 2.166(5) Å and for CϵN from 1.134(6) to 1.157 (7) (7)°to 179.5(10)°, whereas the angles for the two bridging cyanide groups are 175.3(7)°(N1ϵC1-Mo1) and 178.5(7)°(N2ϵC2-Mo1), respectively. All bond lengths and angles in Mo(CN) 8 of complexes 1 and 2 are comparable with those in reported the literature.…”

Magnetism in Heterobimetallic and Heterotrimetallic Chains Based on the Use of [WV(bipy)(CN)6]– as a Metalloligand

“…Furthermore, the cyanido bridges are able to mediate strong magnetic interactions between paramagnetic metal ions. Homoleptic cyanido complexes, [M III (CN) 6 ] 3– and [M IV/V (CN) 8 ] 4–/3– , where M III = Fe, Cr, Mn, and M IV/V = Mo, W, were largely exploited affording a plethora of heterometallic polynuclear complexes . Another option is to employ the heteroleptic cyanido‐bearing complexes, with various capping ligands.…”