Syntheses, characterizations, and crystal structures of 3d–s/d¹⁰ metal complexes derived from two compartmental Schiff base ligands

Abstract

The present investigation reports the syntheses, characterizations, and crystal structures of nine copper(II)/nickel(II)–s/d¹⁰ complexes, [Cu^IIL¹Na^I(ClO₄)(CH₃CN)] (1), [Cu^IIL¹K^I(ClO₄)(CH₃COCH₃)] (2), [Cu^IIL²Zn^IICl₂]·CH₃CN (3), [(Cu^IIL²)₂Na^I](ClO₄)·CH₃COCH₃ (4), [(Ni^IIL¹)₂K^I](ClO₄) (5), [(Cu^IIL¹)₂Cs^I(ClO₄)]·2CH₃CN (6), [(Ni^IIL¹)₂Cs^I(ClO₄)]·2H₂O (7), [(Cu^IIL²)₂Sr^II(H₂O)₂](NO₃)₂ (8), and [{Cu^IIL²Li^I(H₂O)}₂(μ-H₂O)](ClO₄)₂ (9), where H₂L¹ and H₂L² are two 3-methoxysalicylaldehyde-diamine (H₂L^OMe) ligands in which the diamine moieties are o-phenylenediamine and trans-1,2-diaminocyclohexane, respectively. Among these nine compounds, three (1, 2, and 3) are dinuclear, five (4, 5, 6, 7, and 8) are trinuclear, and 9 is tetranuclear. Trinuclear 6 and 7 are double-decker sandwich systems. Some (in 3 and 9) or all (in 1, 2, and 4–8) of the four oxygens of the O(phenoxo)₂O(methoxy)₂ compartment(s) are coordinated to the second metal ion (Na^I in 1 and 4, K^I in 2 and 5, Zn^II in 3, Cs^I in 6 and 7, Sr^II in 8, and Li^I in 9). The di/tri/tetranuclear molecules in 2–9 are self-assembled by weak attractions, such as hydrogen bonds/cation (K^I) π/C–H π interactions. The following self-assemblies are observed: 1-D in 3, 7, and 9, 1-D ladder in 4, 2-D in 8, and 3-D in 2 and 5.

Keywords:

• Heterometallic
• Compartmental ligands
• Self-assemblies
• s-Block metal ions
• Double-decker

Acknowledgments

Financial support from Government of India through DST (Project No. SR/S1/IC–42/2011) and CSIR (Fellowship to S. Mondal) is gratefully acknowledged. DST-FIST is acknowledged for providing Single Crystal X-Ray Diffractometer Facility at Department of Chemistry, University of Calcutta.