Synthesis, Spectroscopic and Structural Systematics of Complexes of Germanium(IV) Halides (GeX4, X = F, Cl, Br or I) with Mono-, Bi- and Tri-Dentate and Macrocyclic Nitrogen Donor Ligands

摘要

The six-coordinate adducts cis-[GeX4(L-L)] (L-L = 2,2'-bipyr-idyl, 1,10-phenanthroline, or Me2NCH2CH2NMe2, X = F, Cl or Br) have been synthesised and characterised by IR and VT ~1H and ~(19)F{~1H} NMR spectroscopy. X-ray crystal structures reveal distorted octahedral geometries and the trends in d(Ge-N) with halide are interpreted in terms of varying Lewis acidity within the series. The trans- [GeX4(py)2] were similarly characterised. In contrast, GeI4 does not form similar adducts, although it appears to co-crystallise with some of the ligands, and the structure of GeI4 centre dot (1,10-phenH)3 centre dot I3 which contains phenanthrolinium cations, iodide anions and tetrahedral GeI4 molecules is reported. Multidentate nitrogen donor ligands including cyclam (1,4,8,11-tetraazacyclo-tetradecane) and Me4-cyclam (1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane) react with [GeF4(MeCN)2] to form insoluble compounds [(GeF4}2(macrocycle)] (F4N2 donor sets). In contrast, Me3[9]aneN3 (1,4,7-trimethyl-1,4,7-triaza-cyclononane) forms the cation [GeF3{Me3[9]aneN3}]~+ with a facial geometry (N3F3 donor set) which is the first example of displacement of fluoride from GeF4 by a neutral ligand.