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Reaction of 8-hydroxyquinoline (HOQ) with holmium metal in the presence strontium metal and metallic mercury at 190°C under vacuum in a 1,3,5-tri-tert-butylbenzene flux yielded (η 2 -8-quinolinolato-κ:N,O(Ho(2))bis(η 2 -8-quinolinolato-κ:N,O(Ho(1)))hexakis(µ-(O)-8-quinolinolato-κ:N,O(Ho(1))trisholmium(III) as an 8-hydroxyquinoline solvate (1) (C2/c, a ϭ 17.336(4) Å , b ϭ 2647 23.464(5), c ϭ 18.038(4) Å , β ϭ 92.92(3)°, V ϭ 7328(3) Å 3 , R1 ϭ 0.0622).The complex was resynthesised after preactivation of the metals by mercury and then heating them with HOQ at 190°C.

Reaction of 8-hydroxyquinoline (HOQ) with calcium and neodymium metal (mole ratio 1.6:0.72:1.1) in the presence of mercury at 110°C under vacuum in a durene flux yielded bis(8-quinolinolato-κ:N,O(Nd))hexakis(µ-(O)-8-quinolinolato-κ:N(Nd),O-(Nd,Ca))calcium(II) dineodymium(III) (NdCaNd) (1) (P1, a ϭ 11.305 (2), b ϭ 12.468(3), c ϭ 13.918(3) Å , Ͱ ϭ 116.62(3), β ϭ 95.46(3), γ ϭ 109.59(3)°, V ϭ 1580.6(6) Å 3 , R1 ϭ 0.0718). The trimetallic was again obtained but as the solvate 1. (HOQ) from Although 8-hydroxyquinoline (HOQ) and its derivatives have long been used in the quantitative determination (gravimetric, colourimetric, volumetric) of lanthanoids [1], little is known of their structures, particularly the Ln(OQ) 3 species implicated in analytical determinations. Recently, two oxyquinolinelanthanoid heteroleptic complexes were isolated as the trinuclear species [Yb 3 (OQ) 8 (OOCCH 3 )]·3CHCl 3 and [Er 3 (ClOQ) 8 (OOCCH 3 )] (ClOQ ϭ 5-chloro-8-quinolinolate) [2,3]. As a new approach to preparing Ln(OQ) 3 complexes, we have examined the direct synthesis from lanthanoid metals and 8-hydroxyquinoline at elevated temperatures either solvent free or in an inert flux.This method has been recently developed for lanthanoid complexes from weak acids [4], e.g. giving phenolates [5,6] and derivatives of nitrogen heterocycles including pyrazolates [7Ϫ10]. Following the fortuitous formation (see below) of a heterobimetallic complex, we have developed this synthesis to give the homoleptic bimetallic complexes [Nd 2 Ca(OQ) 8 ] (1) and [Nd 2 Ca(OQ) 8 ].(HOQ) (1·HOQ) from a mixture of calcium and neodymium metals. Preparation of several yellow crystals of 1 was initially a fortuitous result arising from a trace calcium contaminant in an aged sample of 8-hydroxyquinoline. In a deliberate synthesis, neodymium filings were treated with pieces of calcium and 8-hydroxyquinoline in the presence of an inert flux of 1,3,5-tri-tert-butylbenzene (tBuB) yielding 1·HOQ (Equation (1)). Although a monosolvate, it has the same morphology as 1. Repetition of this reaction but with a different flux (1,2,4,5-tetramethylbenzene (durene)) and a larger excess of metals (Nd:Ca:HOQ 1.0:0.72:1.1) afforded many yellow crystals of 1 (identified by unit cell data) rather than 1·HOQ. In 1 and 1·HOQ, the two eight coordinate neodymium atoms (Figure 1a) have a distorted dodecahedral geometry [11] and are symmetry related with the calcium atom positioned on a centre of inversion. The Nd atoms have one terminal chelating (O, N) oxyquinoline ligand and three chelating (O, N) ligands that are also bridged through their oxygens to calcium (Equation (1)).The four nitrogen * Prof. Glen. B. Deacon 1541 reaction between HOQ, Nd and Ca, (mole ratio 2.8:2:1) in a 1,3,5tri-tert-butylbenzene flux P1, a ϭ 10.206 (2), b ϭ 12.256(3), c ϭ 13.819(3) Å , Ͱ ϭ 85.93(3), β ϭ 89.94(3), γ ϭ 81.36(3)°, V ϭ 1704.5(6) Å 3 , R1 ϭ 0.0592).

The preparations and characterisations of a range of lanthanoid 4-(R)-substituted (4-Rcinn, R ϭ OH, OMe, NO 2 , Cl), known to have good anticorrosion properties, are reported. The crystal structure of [Ce(4-OHcinn) 3 (MeOH) 2 (H 2 O)] · MeOH is a polymer, in which the cerium atoms are nonacoordinate, and 833 adjacent cerium atoms are bridged by either two bridging bidentate or two bridging tridentate carboxylate ligands. Each cerium atom also has one monodentate 4-hydroxycinnamate ligand, one aqua ligand, and two methanol ligands.