Controlling Aggregation of Copper(II)-Based Coordination Compounds:  From Mononuclear to Dinuclear, Tetranuclear, and Polymeric Copper Complexes

Abstract

The use of a strategy combining ligand design and changes of reaction conditions has been investigated with the goal of directing the assembly of mononuclear, dinuclear, tetranuclear, and polymeric copper(II) complexes. As a result, closely related copper monomers, alkoxo dimers, and hydroxo cubanes, along with a carbonate-bridged polymeric species, have been synthesized using the rigid, aliphatic amino ligands cis-3,5-diamino-trans-hydroxycyclohexane (DAHC), cis-3,5-diamino-trans-methoxycyclohexane (DAMC), and the glutaryl-linked derivative glutaric acid bis-(cis-3,5-diaminocyclohexyl) ester (GADACE). The composition of the monomeric complex has been determined by X-ray crystallography as [Cu(DAHC)2](ClO4)2 (1), the two dimers as [{Cu(DAHC)(OMe)}2](ClO4)2.MeOH (2) and [{Cu(DAMC)(OMe)(ClO4)}2] (3), the three Cu4O4 cubanes as [{Cu(DAHC)(OH)}4](ClO4)(4).2.5MeOH (4), [{Cu(DAMC)(OH)}4](ClO4)4.H2O (5), and [{Cu2(OH)2(GADACE)}2]Cl4.2MeOH.6H2O (6), and an infinite-chain structure as [{Cu(DAHC)(CO3)}n] (7). Furthermore, the cubane structures 4 and 5 have been investigated magnetically. Our studies indicate that formation of the monomeric, dimeric, and tetranuclear DAHC and DAMC complexes can be controlled by small changes in reaction conditions and that further preorganization of the ligand moiety by linking the DAHC cores (GADACE) allows more effective direction of the self-assembly of the Cu4O4 cubane core.

Metal‐Dependent Formation of Mononuclear Complexes and M2L2 Mesocates with Schiff‐Base Ligands

“…[11] Recent work in our laboratory has focused on the synthesis and coordination behaviour of the small, cyclohexanebased aliphatic amino ligands r-1,t-3,t-5-triaminocyclohexane (TACH) [12][13][14] and t-3,t-5-diamino-r-1-hydroxycyclohexane (DAHC). [15][16][17] While becoming rigid upon coordination due to conformational locking of the cyclohexane 3930 coordinate dinuclear mesocate structures [{Ag(DDOP)} 2 ]-(CF 3 SO 3 ) 2 (3) and [{Ag(DDMOP)} 2 ](CF 3 SO 3 ) 2 ·0.5MeOH (4). It is thought that the mononuclear, octahedral complexes in the case of zinc(II) and cadmium(II) result from the energetic stabilisation gained through two extra coordinate bonds, while in the case of silver(I) the lower propensity of the metal centre for six-coordination causes the ligand to retain its energetically preferred dinucleating conformation and to form the mesocates.…”

Rhomboidal [Cu 4 ] coordination cluster from self-assembly of two asymmetric phenoxido-bridged Cu 2 units: Role of μ 1,1 -azido clips

“…Azido groups from sodium azide next simultaneously bind two copper(II) ions and clip (me = methoxido) bond distances fall in 1.910-1.930Ǻ range, which are comparable to those reported for other μ-OMe-bridged tetranuclear copper(II) complexes. 15,16 On the other hand, the in-plane phenoxido binding is asymmetric with two Cu-O ph (ph = phenoxido) distances of 1.936 (Cu1) and 1.987 (Cu2) Å, respectively. In their square-pyramidal coordination environment, the Cu1 and Cu2 are displaced by 0.098 and 0.229Ǻ, respectively, from the N 2 O 2 mean basal planes.…”

Synthesis, Characterization and Property Studies on a Dinuclear Copper(II) Complex with Dipyridine Derivate and Acetylacetone

“…In addition, the reaction conditions appear crucial in designing the dinuclear complexes. 19 Herein, we report the synthesis, crystal structure and properties of a dinuclear copper(II) complex with a bridged bidentate bipyridyl ligand of 1,4-di(4-pyridylethene-2-yl-)benzene(dipyph), which was synthesized by our group, and the organic chelating ligand of acetylacetone (aceace).…”