P. Moore

Pyridyl-, bipyridyl-, and terpyridyl-functionalised azamacrocycles

Abstract A series of azamacrocycles which have been N-functionalised with pendent pyridylmethyl-(pyCH2-), bipyridylmethyl-(bipyCH2-) and terpyridylmethyl- (terpyCH2-) arms have been synthesised and characterised, and some of their coordination chemistry with transition metal ions is reported. By attaching the pendent-arms at the 5- rather than the 6-position of the py, bipy and terpy, new ligands are generated which can be used to form polynuclear metal complexes in a controlled and systematic fashion. Fluorescent pH and transition metal ion sensors have been developed by reacting the azamacrocyclic N-pendent bipyCH2 arm(s) with cis-[Ru(bipy)2Cl2], to give macrocycles with up to four attached [Ru(bipy)3]2+ groups. That based on 1,4,7-triazacyclononane (9N3), with three attached [Ru(bipy)3]2+ groups, has a first photo excited state pKa of 7.1, and is a useful fluorescent sensor for physiological pH at below micromolar concentrations. The analogous derivative of cyclam (1,4,8,11-tetraazacyclotetradecane) ca...

N,N'-Bis(2-hydroxybenzylidene)-2,2-dimethyl-1,3-propanediamine

In the title compound, C19H22N2O2, the average N⋯O separation of 2.580u2005(4)u2005A is indicative of intramolecular hydrogen bonding within each salicylideneimine unit. The two aromatic rings are inclined at an angle of 68.66u2005(11)° and this results in a conformation which is inappropriate for quadridentate ligand activity.

Studies of pendant-arm macrocyclic ligands. Part 5. Synthesis of two pyridine-containing penta-aza macrocycles with single pyrrolidinyl pendant arms and characterisation of their nickel(II) and copper(II) complexes. Crystal structure of perchlorato{7-[2′-(1″-pyrrolidinyl)ethyl]-3,7,11,17-tetra-azabicyclo[11.3.1]heptadeca-1(17),13,15-triene}nickel(II) perchlorate

Two new pyridine-containing penta-aza macrocyclic ligands, 7-[2′-(1″-pyrrolidinyl)ethyl]- and 7-[3′-(1″-pyrrolidinyl)propyl]-3,7,11,17-tetra-azabicyclo[11.3.1]heptadeca-1 (17),13,15-triene (L1 and L2 respectively) have been prepared, and their nickel(II) and copper(II) complexes of formulae [M(L1)(OClO3)][ClO4] and [M(HL)][ClO4]3(M = Ni or Cu, L = L1 or L2) have been isolated and characterised. In the octahedral complex [Ni(L1)(OClO3)][ClO4] the presence of a co-ordinated perchlorate group has been established by X-ray crystallography, and the macrocyclic ligand found to co-ordinate close to the corners of a square pyramid with the pendant pyrrolidinyl group at the apical position.

Ligands designed to impose tetrahedral co-ordination: a convenient route to aminoethyl and aminopropyl pendant arm derivatives of 1,5,9-triazacyclododecane

The macrocyclic ligands 1-(2-aminoethyl)-(L1) and 1-(3-aminopropyl)-1,5,9-triazacyclododecane (L2) have been synthesised from 2,4-dioxo-1,5,9-triazacyclododecane, and the complexes [ZnL1(OClO3)]ClO4(trigonal bipyramidal) and [NiL2(NCS)2](octahedral) characterised by X-ray crystallography; L1 and L2 form more stable complexes than do analogues bearing tertiary amino groups on the pendant arms, but allow higher co-ordination numbers.

Two schiff base ligands derived from 1,2-diaminocyclohexane

The crystal structures of the free ligands 2,2-[(1,2-cyclohexanediyl)bis(nitrilomethylidyne)]bisphenol, C 20 H 22 N 2 O 2 , (I), and 2,2-[(1,2-cyclohexanediyl)bis(nitriloethylidyne)]bisphenol, C 22 H 26 N 2 O 2 , (II), have been determined. In both molecules the N-O distances are indicative of intramolecular hydrogen bonding. In compound (I), the two aromatic rings are inclined at an angle of 56.5 (1)° and the O...O separation is 6.082 (3) A ; in compound (II) the corresponding values are are 83.15(8)° and 5.544(5)A. Thus, it is evident that the methyl groups in (II) have a very significant effect upon the overall conformation.

A general synthetic route to fully N-alkylated azamacrocycles, and an uncommon geometry for a six-coordinate nickel(II) complex of 1,4,8,11-tetrapropyl-1,4,8,11-tetraazacyclotetradecane (L1). Crystal structure of trans-(R,S,R,S)-[Ni(L1)(NCS)2]

A two-step route to a range of fully N-alkylated azamacrocycles has been developed; the crystal structure of trans-[Ni(L1)(NCS)2](L1= 1,4,8,11-tetrapropyl-1,4,8,11-tetraazacyclotetradecane) shows the nickel(II) to be six-coordinate, but with the uncommon (R,S,R,S)-or trans-(I)-set of N-configurations.

A 1H NMR study of the factors affecting the internmolecular interaction between the phenyl rings and the mercury(II) ion of several methylmercury(II) complexes containing substituted phenyl groups

Abstract Complexes of methylmercury(II) ion have been prepared with several homologous series of ligands which contain phenyl rings: (1) C6H5(CH2)nX(X = NH2, S−, n = 1, 2, 3; and X = CO−2, n = 0, 1, 2) and (2) p-R-C6H4(CH2)n−1 CH(NH2)CO−2 (R = H, n = 2, 3; R = OH, n = 2). The observation of a high field shift of the [MeHg]+ 1H nmr resonance is interpreted as an anisotropic shielding effect due to an intramolecular interaction between the mercury(II) ion and the phenyl ring. Such an interaction is only observed for series (1) when X = NH2 or S− and n = 1 or 2. In the case of the N-bound methyl(L-tyrosinato)mercury(II), there is fairly good agreement between the crystal structure and that observed in solution, as estimated from the anisotropic shift and conformational analysis based on the backbone vicinal coupling constants. A similar conformational analysis is reported for the complex formed with L-3- phenylalanine.

Two schiff base ligands derived from 2,2-dimethyl-1,3-propanediamine

The crystal structures of 2,2-[2,2-dimethyl-1,3-propanediylbis(nitrilopropylidyne)]diphenol, C 23 H 30 N 2 O 2 , and 2,2-{2,2-dimethyl-1,3-propanediylbis[nitrilo(phenyl)methylidyne]}diphenol, C 31 H 30 N 2 O 2 , have been determined. The N...O contact distances in both molecules are indicative of intramolecular hydrogen bonding. The molecular conformations are compared and shown to be very similar.

Two Schiff Base Ligands Derived from 1,2-Diaminoethane

The structures of two Schiff base ligands, 2,2-[(1,2-ethanediyl)bis (nitrilopropylidyne)] bisphenol, C 20 H 24 -N202, (I), and 2,2-{(1,2-ethanediyl)bis[nitrilo(phenyl)-methylidyne]}bisphenol, C 28 H 24 N 2 O 2 , (II), are reported. The molecular structure of (I) is centrosymmetric and therefore has a trans conformation. The asymmetric unit for structure (II) contains two molecules, but both have gauche arrangements. Structures (I) and (II) both contain the enolimine tautomers and exhibit intramolecular hydrogen bonding.

1,4,7-Tris(2,2′-bipyridyl-5-ylmethyl)-1,4,7-triazacyclononane (L1), a powerful tris(2,2′-bipyridyl) chelating macrocyclic ligand. X-Ray structure of [Ru(L1H)][PF6]3, a complex containing a strongly trapped proton

A new powerful tris(2,2′-bipyridyl) chelating ligand, 1,4,7-tris(2,2′-bipyridyl-5-ylmethyl)1,4,7-triazacyclononane (L1), has been synthesised and characterised, and an X-ray structure of [Ru(L1H)]3+ obtained; in the complex all three bipyridyl groups are coordinated, with a fairly regular octahedral RuII geometry, and although the azamacrocyclic nitrogen-atoms are non-coordinating to RuII, in aqueous solution they trap a single proton in the cavity between the macrocycle and the RuII, and which cannot be removed even at high pH.