Oxidation of alkali metal derivatives of the dianions [E((t)BuN)P(μ-N(t)Bu)(2)P(N(t)Bu)E](2-) (E = S, Se) with I(2) produces 15-membered macrocycles in which a planar P(6)E(6) motif is stabilised by perpendicular P(2)N(2) scaffolds.

No abstract

The reaction of 1,1′-ferrocenedicarboxylic acid, LH 2 , with diorganotin halides R 2 SnCl 2 (R ) n-Bu and Bn) or Ar 2 TeCl 2 (Ar ) 4-OMe-C 6 H 4 ) in the presence of triethylamine afforded, in nearly quantitative yields, heterobimetallic tetranuclear macrocycles [R 2 SnL] 2 and [Ar 2 TeL] 2 . The molecular structures of these compounds have been confirmed by single-crystal X-ray analysis and show that the two maingroup metal atoms within each macrocycle are bridged to each other by two ferrocene carboxylate ligands. In the case of the organotin derivatives the ferrocenedicarboxylate ligand acts in an anisobidentate chelating manner, leading to a hexacoordinate tin present in a skewed trapezoidal bipyramid geometry. In contrast, in the tellurium analogue the ferrocenecarboxylate ligand is monodentate, leading to a tetracoordinate tellurium in a seesaw geometry. ESI-MS studies on these macrocylic complexes reveal that they retain their structural integrity in solution. Electrochemcial studies reveal that [n-Bu 2 SnL] 2 and [Ar 2 TeL] 2 show two quasi-reversible oxidation processes. These compounds have low comproportionation constants (K c ) and can be described as being intermediate between noncoupling and weakly coupled systems. [Bn 2 -SnL] 2 also shows two oxidation processes. However, in this instance, the second event is irreversible.

The reaction of 1,1,2,3,3-pentamethyltrimethylenephosphinic acid (cycPO(2)H) with bis(p-methoxyphenyl)tellurium dichloride (1) affords a 12-membered macrocycle [((p-MeOC(6)H(4))(2)Te)(2)(mu-O)(mu-cycPO(2))(mu(4)-Cl)](2) x C(6)H(6) (2) in good yield. The latter reacts with sodium iodide to give [((p-MeOC(6)H(4))(2)Te)(2)(mu-O)(mu-cycPO(2))(mu(4)-I)](2) x 4 C(6)H(6) (3). 2 and 3 are isostructural dicationic macrocycles and contain a Te(4)P(2)O(6) framework. An interesting aspect of both of these structures is that two counter halide atoms are present as capping ligands above and below the macrocyclic plane enabled by Te-X interactions. In contrast to the macrocyclic product obtained with diorganotellurium dihalide the reaction of diphenyltin dichloride with cycPO(2)H resulted in the formation of an oxygen-capped cluster [(PhSn)(3)(mu(3)-O)(mu-cycPO(2))(3)(mu-OH)(3)][cycPO(2)] x CH(3)CN. The latter is formed by a Sn-Ph cleavage reaction.

The reaction of 1,1'-ferrocenedicarboxylic acid (LH(2)) with bis(triphenyltin) oxide afforded a molecular heterobimetallic compound [(Ph(3)Sn)(2)L]. In the latter the two carboxylate units of [L](2-) are involved in an anisobidentate chelating coordination mode to two triphenyl tin units. The reaction of LH(2) with trimethyltin hydroxide or bis(tri-n-butyltin) oxide afforded 2D-coordination polymers [(Me(3)Sn)(2)L](n) and [(n-Bu(3)Sn)(2)L](n) which are formed as a result of anisobidentate bridging coordination action of the two carboxylate units of [L](2-). Interestingly the 2D-coordination polymers contain 24-membered macrocycles each of which is comprised of four trialkyl tin units. The coordination unsaturation of [(Ph(3)Sn)(2)L] can be utilized to form coordination polymers. Accordingly the reaction of LH(2) with bis(triphenyltin) oxide in the presence of ditopic nitrogen ligands such as 4,4'-bipyridine, 4,4'-trimethylenebipyridine or 4,4'-vinylenebipyridine afforded one-dimensional coordination polymers which contain in their backbone three distinct structural components viz., two triorganotin units, a ferrocenyl unit and a bridging nitrogen ligand unit. The coordination polymers, however, do not retain their structural integrity in solution and fall apart to their monomeric units. Electrochemical studies on these hybrid orgaonotin/ferrocene systems reveal that most of them exhibit a single quasi-reversible oxidation peak.