The coordination of AlCl(3) by the complex [{MeAl(2-py)(3)}Li.thf] () gives the unusual product [{MeAl(2-py)(3)}(2)Al](+)[{MeAl(2-py)(3)}Li](2)(mu-Cl)(-) (), in which the [MeAl(2-py)(3)](-) aluminate anion of acts cooperatively in the coordination of an Al(3+) cation and Cl(-) anion.

Reactions of the lithium salts [{RAl(2-py')3Li·THF] [2-py' = 2-py (2-pyridyl), R = (n)Bu (1), R = (sec)Bu (2); py' = 5-Me-2-py (5-methyl-2-pyridyl), R = Me (3); 6-Me-2-py (6-methyl-2-pyridyl), R = Et (4b)] with the corresponding metal(ii) halides give the new heterobimetallic sandwich compounds [{RAl(2-py)3}2M] [R = (n)Bu, M = Ca (5), Mn (6), Fe (7); R = (sec)Bu, M = Ca (8), Mn (9)], [{MeAl(5-Me-2-py)3}2Ca] (10) and [{EtAl(6-Me-2-py)3}2Ca] (11) and the co-complex [{EtAl(6-Me-2-py)3}Mn(μ-Cl)Li{(6-Me-2-py)3AlEt}] (12). While neither the bridgehead group (R) nor remote ring Me-groups have any impact on metal coordination in 5-10, the introduction of Me groups into the pyridyl substituent at the 6-position (i.e., adjacent to the donor pyridyl-N atoms) has a marked effect on the ability of the ligands to form sandwich arrangements, as seen in the distorted structure of the sandwich compound 11 and in the formation of the co-complex 12, consisting of a two half-sandwich arrangement linked by a μ-Cl ion. The syntheses and solid-state structures of the new precursor 4b and the new compounds 5-12 are reported.

The synthesis and structure of [{MgCl(thf)2}3(mu3-C3H5)2]2[Mg(C3H5)4], which contains both a cationic cluster Grignard and a tetraorganomagnesiate dianion, are reported.

A series of tris-pyridyl complexes [RAl(2-py)(3)]Li.thf [2-py = 2-pyridyl; R = Et (1); (n)Bu (2); (s)Bu (3), (t)Bu (4)] were prepared by the sequential reaction of AlCl(3) with RLi then 2-Li-py in thf. The related complexes [MeAl{2-(3-Me)py}(3)]Li(mu-Br)Li(thf)(3) (5), [MeAl{2-(5-Me)py}(3)]Li.thf (6) and [MeAl{2-(6-Me)py}(3)]Li.thf (7) are obtained similarly from MeAlCl(2) and the appropriate lithio-pyridine (2-Li-py'). The synthetic approaches used provide the means for extensive elaboration of the [RAl(2-py')(3)](-) ligand frameworks, and potentially broad access to a large range of new anionic tris-pyridyl ligands of this type. Fundamental insights into how the ligand bites and coordination environments offered are modified by substituents at the Al bridgehead and pyridyl rings are given by the solid-state structures of 1-7 .