The Dimeric “Hand‐Shake” Motif in Complexes and Metallo–Supramolecular Assemblies of Cyclotriveratrylene‐Based Ligands

Abstract

A series of clathrate and metal complexes with cyclotriveratrylene-like molecular host ligands show a similar dimeric homomeric inclusion motif in which a ligand arm of one host is the intra-cavity guest of another and vice versa. This "hand-shake" motif is found in the trinuclear transition metal complex [Cu(3)Cl(6)(1)]CH(3)CN1.5 H(2)O in which 1 is tris(4-[2,2',6',2''-terpyridyl]benzyl)cyclotriguaiacylene; in the self-included M(4)L(4) tetrahedral metallo-supramolecular assembly [Ag(4)(2)(4)] (BF(4))(4) in which 2 is tris-(2-quinolylmethyl)cyclotriguaiacylene; in the 1D coordination chains [Ag(4)]ReO(4) CH(3)CN and [Ag(5)]SbF(6)3 DMFH(2)O in which 4 is tris(1H-imidazol-1-yl)cyclotriguaiacylene and 5 is tris{4-(2-pyridyl)benzyl}cyclotriguaiacylene; and in the acetone clathrate of tris{4-(2-pyridyl)benzyl-amino}cyclotriguaiacylene. Clathrates of ligands 2 and 5 do not show the same dimeric motif, although 2 has an extended homomeric inclusion motif that gives a hexagonal network.

Lanthanide coordination polymers with pyridyl-N-oxide or carboxylate functionalised host ligands

“…[47][48][49][50] The previously unreported ligand (±)-tris(2-quinolylmethyl)-tris(propoxy)-cyclotricatechylene (L2p) was prepared through reaction of propylated-cyclotriguaiacylene (p-CTG) 46 with 2-chloromethylquinoline in basic acetonitrile (MeCN), using an adapted version of a previously reported procedure, and isolated as a racemic mixture in high yields. 47 Ligands L1m, L1p, L2m and L2p were employed as racemic mixtures for all coordination studies and their molecular structures can be seen in Scheme 1. Whilst individual ligand pairs are essentially isostructural and differ only by the length of ortho-alkoxy substituents, we postulate that their dissimilar coordination chemistry may be attributable, in part, to aggregation effects present in the complexes of the longer-chained ligands.…”

“…An analogous complex to 2p but with ligand L1m in place of 4 ]·4(BF 4 ), complex 3m, Figure 3. 47 Complex 3m is close-packed and displays a hydrophobic core with four inwardly pointing methyl moieties in close proximity to one another. Despite our best efforts, metallo -supramolecular constructs were not identified to form from L2m with other transition metals.…”

“…Highlighting the twisted tetrahedral core, and (b) space-filling diagram displaying the resultant cube-like appearance. 47 The asymmetric unit contains two molecules of ligand L2p, two Ag(I) cations, and two [Co(C 2 B 9 H 11 ) 2 ] -counter anions, alongside nitromethane solvent. The 1D coordination polymer formed is a racemate and features the inclusion of both enantiomers of L2p ligands per 1D chain, Figure 4.…”

“…The two ligands in the asymmetric unit are of the opposite enantiomer to one another which results in a mesocomplex, akin to complex 3m. 47 Pd(II) centres are square planar and are exclusively trans coordinated by the quinolyl donors and display Pd-N bond lengths in the range 2.051(6)-2.070(7) Å and N-Pd-N angles of 176.3(3), 177.2(3) and 177.5(4)°. Two trifluoroaceta te anions coordinate each palladium(II) centre to render the overall complex charge-neutral and display Pd-O bond lengths ranging 1.971(7)-2.060(9) Å, and O-Pd-O angles of 172.5(3), 175.0(3) and 176.5(3)°, Figure 5.…”

Hexasulfanyl analogues of cyclotriveratrylene

“…This "handshake" dimerization is common in crystalline CTV derivatives, which associate by intermolecular inclusion of their methyl groups ( Figure 2). 19 The observation of the same motif in 4c, despite the increased bulk of the included iso-propyl groups, indicates that the host:guest chemistry of 4a-4d should be comparable to CTV derivatives. In conclusion, we have reported here a general synthesis of 3,4-di(alkylsulfanyl)benzyl alcohols, employing a Newman-Kwart rearrangement procedure.…”