Jonathan P. Danks

Chemistry of mixed nitrogen- and sulfur-donor tridentate macrocycles

Abstract The synthesis and co-ordination chemistry of tridentate N/S-mixed donor macrocycles is reviewed.

Self-assembly of a polynuclear ribbon: the structure of {[Cu2(CN)2(L)]·MeNO2}∞ [L=4,7-bis(2-cyanoethyl)- 1-thia-4,7-diazacyclononane]

The compound {[Cu2(CN)2(L)]·MeNO2}∞ [L=4,7-bis(2-cyanoethyl)-1-thia-4,7-diazacyclononane] has been prepared by reaction of CuCN with L. The complex shows an unusual CuI–CN one-dimensional polymer capped by macrocyclic ligands.

Synthesis and characterisation of pendant-arm amino derivatives of 1,4,7-triazacyclononane and alkyl-bridged bis(1,4,7-triazacyclononane) macrocycles and complexation to Cu(II)

The new pentadentate and bis(pentadentate) ligands 1-methyl-4,7-bis(3-aminopropyl)-1,4,7-triazacyclononane 6 and 1,2-bis[4,7-bis(3-aminopropyl)-1,4,7-triazacyclonon-1-yl]ethane 14 have been synthesised by reaction of acrylonitrile with the corresponding macrocyclic precursors and subsequent reduction of the nitrile groups with BH3·THF. Cu(II) complexes of the two ligands having formulations [Cu(6)][BF4]2 and [Cu2(14)][PF6]4·6MeCN, respectively, have been prepared and structurally characterised. Both complexes exhibit distorted square-based pyramidal geometries about the metal centres with the two primary amino groups belonging to the pendant arms occupying basal positions [Cu–Nap 2.257(6), Cu–Neq 2.026(6)–2.074(5) A for [Cu(6)]2+, and 2.337(2) and 2.038(3)–2.085(3) A for [Cu2(14)]4+]. The binuclear complex [Cu2(14)]4+ is centrosymmetric about the ethane bridge with the two pentadentate compartments oriented away from one another to give a transoid anti-configuration with a MeCN molecule interacting with each Cu(II) centre at 2.710(4) A. Both complexes have also been characterised by electronic and EPR spectroscopy and by cyclic voltammetry, and their properties compared to those of Cu(II) complexes of analogous macrocyclic ligands having 2-methylpyridyl pendant arms.

Synthesis and characterisation of pendant-arm alcohol derivatives of [9]aneN2S and complexation with CuII ([9]aneN2S = 1-thia-4,7-diazacyclononane)†

An improved detosylation of 4,7-bis(tolyl-p-sulfonyl)-1-thia-4,7-diazacyclononane to give the free amine [9]aneN2S has been accomplished using Li/NH3 or HBr/acetic acid. Reaction of [9]aneN2S with ethylene oxide, 1,1-dimethylethylene oxide and methylenecyclohexane oxide in alcoholic solution affords the potentially pentadentate ligands 4,7-bis(hydroxyethyl)-1-thia-4,7-diazacyclononane (H2L1), 4,7-bis(2-hydroxy-2-methylpropyl)-1-thia-4,7-diazacyclononane (H2L2) and 4,7-bis(2-cyclohexyl-2-hydroxymethyl)-1-thia-4,7-diazacyclononane (H2L3) respectively. The copper(II) complexes of these ligands have been prepared and reveal that increasing the steric bulk on the pendant arm has a marked effect upon the resultant co-ordination chemistry. Thus, the complex of H2L1 shows a dimeric structure [Cu2(HL1)2][PF6]2 1 in which one of the hydroxy groups has been deprotonated. With H2L2 two complexes can be isolated: the dimer [Cu2(HL2)2][PF6]2 2 and the monomer [Cu(HL2)][PF6] 3. In contrast, with H2L3 only the monomer [Cu(HL3)][PF6] 4 could be isolated. Single crystal structures of 1 and 3 have been determined. Magnetochemistry of 1 indicates that the two copper(II) centres are essentially non-coupled.

Synthesis and crystal structure of [Au2(N-Ts[9]aneNS2)Cl2]2 {N-Ts[9]aneNS2=7-(toluenesulfonyl)-7-aza-1,4-dithiacyclononane} incorporating Au···Au and π–π interactions

Reaction of AuCl(tht) (tht=tetrahydrothiophene) with N-Ts[9]aneNS2 {N-Ts[9]aneNS2=7-(toluenesulfonyl)-7-aza- 1,4-dithiacyclononane} affords the tetranuclear Au(I) species [Au2(N-Ts[9]aneNS2)Cl2]2 which exhibits Au···Au and π–π interactions leading to an overall infinite chain structure.

Bis[bis(2-aminoethyl-N)sulfide-S]nickel(II) bis(hexafluorophosphate)

The structure of the title complex, [Ni(C4H12N2S)2](PF6)2, shows a distorted octahedral geometry around the nickel centre, with the two S atoms mutually cis.

4,7-Bis(2-thiophenoyl)-1-thia-4,7-diazacyclononane

The title compound, C 16 H 18 N 202 S 3 , has two thiophenoyl arms linked to the N atoms of the central 1-thia-4,7-diazacyclononane ring. The resulting amide groups are close to planar. One of the thiophene rings shows disorder.