Copper(I) complexes of dinucleating macrocyclic bis(dithiadiimine) ligands

Abstract

hexadecaene (L 2 ) have been synthesized in high yield by a 2 ϩ 2 condensation of isophthalaldehyde and terephthalaldehyde with 2,2Ј-o-phenylenebis(methylenethio)bis(ethanamine) (L 1 ) in acetonitrile. Air-stable dicopper() complexes of L 2 and L 3 were obtained from complexation reactions withconfirmed by a crystal structure analysis. The complex consists of two N 2 S 2 donor sets each tetrahedrally co-ordinated to the copper() ions with two para-substituted phenyl rings bridging the two N 2 S 2 'compartments' π-stacked parallel (separation 3.5 Å), and a double helical arrangement of the ligand backbone clearly evident. Electrochemical studies of the dinuclear complexes revealed quasi-reversible Cu I ᎐Cu II couples above ϩ1 V (versus NHE), with reversibility influenced by the presence of ferrocene, which acts as a surface modifier for electron transfer.

Syntheses and Structural Characterization of Ferrocene-Containing Double-Helicate and Mononuclear Copper(II) and Silver(I) Complexes

“…Although no further proof supports the postulation that the square pyramidal geometry of Cu-(II) and silver(I) complexes 2 and 3 is the main factor causing the molecules not to be formed in a dinuclear fashion, it seems possible that the relatively simple mononuclear complex [AgL(CH 3 CN)] arises in part from the presence of the coordinated acetonitrile. 20,22 We therefore investigated the reaction of ligand L 2 with silver(I) in dichloromethane following the recrystallization of the complex in chloroform as its BF 4salt, whose elemental analysis is consistent with formation of [AgL 2 ](BF 4 ). However, the ESI-MS spectrum also confirms the mononuclear formation of complex 4.…”

“…29 Anisotropic thermal parameters were refined for non-hydrogen atoms. For complex 2, oxygen atoms of the two ClO4anions were refined disordered over two positions, O(12) to O(14) and O (22) to O(24) as well as O(12′) to O(14′) and O(22′) to O(24′), respectively; these two positions were refined to occupancies of 0.56(3) and 0.45(2) as well as 0.44(3) and 0.55(2), respectively. For 3, the BF4anion was disordered over two positions, F(1), F(2), F(3), and F(4) and F(1′), F(2′), F(3′), and F(4′); these two atom positions were refined to occupancies of 0.62(4) and 0.38(4), respectively.…”

Linear free energy relationships from collision-activated dissociation spectra: the electrospray mass spectra of transition metal macrocyclic complexes

“…This is generally far too small to activate a dissociative collision. For example, using the Born approximation, the free energy of hydration for these dinucleating ligands is estimated to bẽ 508 kJ mol -1 (using the minor axis 19 ), which is far in excess of the ambient energy available. It would be anticipated that the activation energy for molecular ion loss would be smaller than the hydration energy, but would still be much larger than the ambient collision energy.…”

“…4,9,14,15 = 910.99) were synthesised in our laboratories, as described elsewhere. 18,19 The structural, spectroscopic and electrochemical properties of complexes of these ligands are understood. 18,19 The L 1 and L 2 ligands used in this study were spectroscopically pure.…”

“…18,19 The structural, spectroscopic and electrochemical properties of complexes of these ligands are understood. 18,19 The L 1 and L 2 ligands used in this study were spectroscopically pure. All solutions were prepared using distilled water.…”