The supramolecular interplay of Me₃Sn⁺ and [M(CN)_2n]ⁿ⁻ ions (n=3 and 4) with either 4,4′-bipyridine (bpy), trans-bis(4-pyridyl)ethene (bpe) or 4cyanopyridine (cpy) in the presence of H₂O has been investigated for the first time. Crystal structures of the six novel assemblies: [(Me₃Sn)₄Mo^IV(CN)₈⋅2 H₂O⋅bpy] (8) and [(Me₃Sn)₄Mo^IV(CN)₈⋅2 H₂O⋅bpe] (8 a; isostructural), [(Me₃Sn)₃Fe^III(CN)₆⋅4 H₂O⋅bpy] (9), [(Me₃Sn)₃Co^III(CN)₆⋅3 H₂O⋅3/2 bpy] (10), [(Me₃Sn)₄Fe^II(CN)₆⋅H₂O⋅3/2 bpy] (11), and [(Me₃Sn)₄Ru^II(CN)₆⋅2 H₂O⋅3/2 cpy] (12) are presented. H₂O molecules are usually coordinated to tin atoms and involved in two significant OH⋅⋅⋅N hydrogen bonds, wherein the nitrogen atoms belong either to bpy (bpe, cpy) molecules or to Mcoordinated cyanide ligands. Extended supramolecular assemblies such as -CNSn(Me₃)O(H⋅⋅⋅)H⋅⋅N(L)N⋅⋅HO(H⋅⋅⋅)Sn(Me₃)NC- (L=bpy, bpe or cpy) function as efficient metal connectors (or spacers) in the structures of all six compounds. Only in the three-dimensional framework of 11, one third of all bpy molecules is involved in coordinative NSn bonds. The supramolecular architecture of 9 involves virtually non-anchored (to cyanide N atoms), Me₃Sn⁺ units with a strictly planar SnC₃ skeleton, and two zeolitic H₂O molecules. Pyrazine (pyz) is surprisingly reluctant to afford assemblies similar to 8–12, however, the genuine host–guest systems [(Me₃Sn)₄Mo(CN)₈⋅0.5pyz] and [(Me₃Sn)₄Mo(CN)₈⋅pym] (pym=pyrimidine) could be isolated and also structurally characterized.

Novel examples of the complex of the type [Ln(Ind)₃·Nic] [Ind = indenyl; Nic = (S)-(−)-nicotine] with Ln = La (2), Pr (3), and Nd (4) have been synthesised, along with their “parent” system [LaCp₃·Nic] (1). Complexes 2−4 were structurally, exhaustively characterised (XRS, ¹H NMR spectroscopy). Attempts to prepare homologues of 3 with achiral N-bases, pyridine, α-picoline, β-picoline, 2,6-dimethylpyridine, 2,6-bis(tert-butyl)pyridine, 2,2′-bipyridine, and 4,4′-dimethyl-2,2′-bipyridine, were successful with only the two least bulky bases, pyridine and β-picoline, which afforded the new adducts 5 and 6, respectively. The chiral [Ln(Ind)₃·Nic] adducts are virtually isostructural, although subtle but systematic conformational variations emerge from the crystal structure analyses. While the unit cells of 2−4 contain two epimeric diastereomers, those of 5 and 6 involve genuine optical antipodes. The chiral carbon atom of nicotine lies approximately twice as far from the metal centre than the chiral sulfur atom of the methyl tolyl sulfoxide (MTSO) ligand in the previously reported [Ln(Ind)₃·MTSO] systems. As a result of this, the impact of the chiral MTSO ligand, both on the molecular structure and the ¹H NMR spectra, is found to be notably stronger than that of (S)-(−)-nicotine. The comparatively weak f-f circular dichroism of 3 is also compared with that of its (S)-(−)-MTSO-containing congener.

Threepairsofprochiralringprotons make the η⁵-coordinated indenyl ligand a promising new auxilliary to study rapid intermolecular exchange processes of chiral ligands by solution NMR. The title complexes [Ln(C₉H₇)₃⋅L*], which contain two chirogenic centres both in the solid state (illustrated for Ln and Ln′) and in solution, are found to exchange, for example, (R)-(+)-MTSO for (S)-(−)-MTSO, or achiral DPSO readily, but not Ln-coordinated THF (MTSO=methyl-p-tolyl-sulfoxide; DPSO=diphenylsulfoxide).

The new coordination polymer [(Me₃Sn^IV)₃Rh^III(SCN)₆] = [Rh{μ-(SCNSnMe₃NCS)}₃] (5) is readily accessible by straightforward self-assembly of [Rh(SCN)₆]^3- and (dehydrated) {Me₃Sn} ions. The architecture of 5 is strongly reminiscent of “super-Prussian-blue” systems reported earlier: there is a three-dimensional (3-D) framework involving {Rh₈} pseudocubes as the basic building blocks, the Rh³⁺ ions being held apart by novel, nonlinear {SCN-SnMe₃-NCS} spacers (d(Rh…Rh) = 1.27 nm). The complete lattice consists of two equivalent and independent, ideally interwoven 3-D frameworks. Three homologues of 5 with slightly modified R₃Sn units (R = Et, nPr and nBu) have been prepared as well, but display X-ray powder diffraction patterns notably different from that of 5.