One-dimensional coordination polymers constructed from di- and trinuclear {3d–4f} tectons. A new useful spacer in crystal engineering: 1,3-bis(4-pyridyl)azulene

Abstract

Four new heterometallic 3d-4f complexes have been obtained using bi-and trinuclear building blocks:1acetoacetyl)pyridine, azbbpy = 1,3-bis(4-pyridyl)azulene, dca − = dicyanamide anion, and oxy-bbz = the dianion of the 4,4′-oxy-bis(benzoic) acid]. 1 and 2 represent the first complexes containing 1,3-bis(4-pyridyl)azulene as a ligand. 1, 3, and 4 are one-dimensional coordination polymers constructed from heterometallic nodes connected by the exo-dentate ligands. Helical chains are assembled in the case of 4. The analysis of the packing diagram for 1 reveals the occurrence of π-π stackinginteractions established between the azulene rings from neighboring chains, which lead to supramolecular layers. The magnetic properties of 3 in the temperature range 1.9-300 K have been investigated.Intra-node ferromagnetic interactions are established between the Cu II and Gd III ions (J = +2.7 cm −

Syntheses and Structures of New Trinuclear MIILnMII (M = Ni, Co; Ln = Gd, Ce) Complexes with 2, 6‐Bis(acetobenzoyl)pyridine

“…Both 1a and 1b reveal trinuclear {NiLnNi(L) 2 } 3+ cores, which are similar to the series of trinuclear complexes {M II LnM II ) with 2,6-bis(acetoacetyl)pyridine ligands. [5][6][7][8] (Figure 1), two acetates act as bridges between the gadolinium and the nickel ions, while the third one is unidentate bonded to Gd III . Also in the molecular structure of 1b (Figure 2), the two bidentate acetates are located above the {Ni 2 Ln(L) 2 } 3+ plane, but only one of them is a bridging ligand between Ce III and one of the Ni II ions, whereas the second one exclusively binds to the central Ce III ion.…”

“…Surprisingly, there are hitherto only a few papers dealing with such compounds. [6,8,9] In the presented work, we report the syntheses and structures of some neutral, trinuclear {Ni II Ln III Ni II } and {Co II Ln III Co II }complexes with 2,6-bis(acetobenzoyl)pyridine (H 2 L, Scheme 1) using acetate and benzoate as co-ligands. The obtained complexes provide examples other than their nitrate congeners for studies of their physicochemical properties and represent trinuclear prototype compounds for tailored supramolecules with bridging bis-carboxylato ligands, the synthesis, of which is planned for the future.…”

“…In all of the reported complexes, the three metal ions are chelated by two dinegative pyridine-2,6-bis(β-diketonato) ligands, which give the thermodynamically stable [ 3 ) n ](NO 3 ) 3-n where nitrates can act as counterions and also as auxiliary ligands. [4][5][6][7][8] (PhCOOH) is added subsequently. Under the same conditions, reactions with the corresponding cobalt(II) salts result in the formation of a neutral [Co 8 (μ 3 -O) 2 (L) 6 ] complex, which has a bis(triple-helical) structure.…”

“…[4][5][6][7][8] (PhCOOH) is added subsequently. Under the same conditions, reactions with the corresponding cobalt(II) salts result in the formation of a neutral [Co 8 (μ 3 -O) 2 (L) 6 ] complex, which has a bis(triple-helical) structure. The cobalt(II) analogues to compounds 1 and 2, however, can be synthesized by a pre-treatment of the lanthanide salts with H 2 L and subsequent addition of the cobalt salts, and benzoic acid (in the case of 2).…”

“…They have three metal binding sites, one central 2,6-diacylpyridine site suitable for lanthanide binding and two terminal 1,3-diketonate sites favorable for transition metal binding. [3,4] [5] Co II , [6] Cu II , [7] or Zn II [8] have been prepared. In all of the reported complexes, the three metal ions are chelated by two dinegative pyridine-2,6-bis(β-diketonato) ligands, which give the thermodynamically stable [ 3 ) n ](NO 3 ) 3-n where nitrates can act as counterions and also as auxiliary ligands.…”