This thesis details the synthesis and structural characterisation of twenty-nine (1-29) new 1st row transition metal complexes constructed using a series of structurally related organic ligands based on a common phenol building block. A chapter content breakdown is given below.
Chapter 2 describe the synthesis of a sixteen (1-16) member family of solid-state host-guest complexes. Here we have successfully encapsulated a series of organic guest moieties (2-furaldehyde, 3-furaldehyde, benzaldehyde, thiophenecarboxaldehyde, 2-acetylfuran and acetophenone) into the molecular cavities within [M(II)7(OR)6(L1)6](NO3)2 (M = Co, Ni and Zn; R = H or CH3 and L1H = 2-Methoxy-6-[(E)-(methylimino)methyl]phenol) pseudo metallocalix[6]arene host complexes. Guest encapsulation has been confirmed using a variety of techniques including FT-IR, single crystal X-ray diffraction and solid-state NMR (in the case of [(2-fur)Zn(II)7(OMe)6(L1)6](NO3)2.3H2O (1) and [(benz)Zn(II)7(OMe)6(L1)6](NO3)2.5H2O (7).

In Chapter 3 we describe the synthesis and characterisation of the ligands 2-Methoxy-6-{(E)-[(2-methoxyphenyl)imino]methyl}phenol (L3H), Methyl 4-[(E)-(2-hydroxy-3-methoxybenzylidene)amino]benzoate (L4H), 2-[(E)-(Benzylimino)methyl]-6-methoxyphenol (L5H), 2-[(Benzylamino)methyl]-6-methoxyphenol (L6H) and 2-[(benzylamino)methyl]-4-bromo-6-methoxyphenol (L7H). These ligands are structurally related to the ligand 2-Methoxy-6-[(E)-(methylimino)methyl]phenol (L1H) used in the construction of the [M7] (M = Co(II), Ni(II) and Zn(II)) host complexes described in Chapter 2. Here we have investigated how the deliberate structural modifications of ligands L1H and L2H (in the form of L3-7H) give rise to a variety of new complexes with varying nuclearities and topologies. For instance, we present the rare ferromagnetically coupled dinuclear complex [Ni(II)2(L3)3(H2O)](NO3)2H2O.3MeOH (17) as characterised using a combination of SQUID and High-Field, High-Frequency EPR studies. We also discuss the structural and magnetic characterisation of the tetranuclear analogues [(NO3)⸦Co(II)4(µ3-OH)2(L6)4(H2O)2](NO3).H2O (21), [(NO3)⸦Ni(II)4(µ3-OH)2(L6)4(H2O)2](NO3).H2O (22) and [Ni(II)4(3-OH)2(L7)4](NO3)2.MeCN (23), whose ‘butterfly’ core topologies are discussed in relation to their heptanuclear pseudo metallocalix[6]arene ancestors [Ni(II)7(3-OH)6(L1)2](NO3)2 and [Co(II)7(3-OH)6(L1)6](NO3)2 (previously reported by the Jones group).

Magnetic susceptibility and magnetisation studies on complex [(NO3)Co(II)4(3-OH)2(L6)4(H2O)2](NO3).H2O (21) and [Ni(II)4(3-OH)2(L7)4](NO3)2.MeCN (23) indicate competing anti- and ferromagnetic exchange between the Co(II) centres in 21 and dominant antiferromagnetic exchange between the Ni(II) ions in 23.

In Chapter 4 we have taken the original ligand 2-Methoxy-6-[(E)-(methylimino)methyl]phenol (L1H) and modified it at the upper rim location by attaching phenyl and tolyl functional groups to give the ligands 2-Methoxy-4-phenyl-6-[(E)-(methylimino)methyl]phenol (L8H) and 2-Methoxy-4-tolyl-6-[(E)-(methylimino)methyl]phenol (L9H), respectively. Interestingly and despite significant structural changes both L8H and L9H still produce the pseudo metallocalix[6]arenes complexes in the form of [Ni(II)7(OMe)6(L8)6](NO3)2.2H2O (25), [Zn(II)7(OH)2(OMe)4(L8)6](NO3)2.4MeOH.10H2O (26) and [Zn(II)7(OMe)6(L9)6](NO3)2.10MeOH.13H2O (27). As intended, this upper rim functionalisation provides the family with extensions to their molecular cavity walls when compared to their previously reported siblings.

We also demonstrate how upper and lower rim functionalisation of the 2-Methoxy-6-[(E)-(methylimino)methyl]phenol (L1H) gives rise to a new duo of ligands employed in the production of the complexes: [Ni(II)2(L10)2(H2O)(NO3)2].2MeCN (28) and [Zn(L11)2] (29) (where L10H is 2-Methoxy-4-phenyl-6-{(E)-[(2-methoxyphenyl)imino]methyl}phenol and L11H is 2-[(E)-(Benzylimino)methyl]-4-phenyl-6-methoxyphenol.