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Synthesis, Structural Characterisation and Solution Behaviour of High‐Symmetry Lanthanide Triflate Complexes with the Sterically Demanding Phosphine Oxides Cy 3 PO and t Bu 3 PO
Author(s) -
Coles Simon J.,
Pitak Mateusz B.,
Platt Andrew W. G.
Publication year - 2017
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201601471
Subject(s) - chemistry , trifluoromethanesulfonate , lanthanide , tricyclohexylphosphine , steric effects , protonation , phosphine oxide , molecule , crystallography , phosphine , nuclear magnetic resonance spectroscopy , medicinal chemistry , pentagonal bipyramidal molecular geometry , stereochemistry , nmr spectra database , crystal structure , ion , organic chemistry , catalysis , spectral line , physics , astronomy
The synthesis and characterisation of complexes formed from lanthanide trifluoromethanesulfonates [Ln(OTf) 3 ] and tricyclohexylphosphine oxide (Cy 3 PO) or tri‐ tert ‐butylphosphine oxide ( t Bu 3 PO) are described. The structures of [Ln(H 2 O) 5 (Cy 3 PO) 2 ] · 2R 3 PO · (OTf) 3 (Ln = Pr, Tm; R = Cy and Ln = Nd; R = t Bu) are pentagonal bipyramidal with an equatorial plane of five H 2 O ligands and two axial Cy 3 PO ligands. The remaining Cy 3 PO molecules are H‐bonded to the coordinated water molecules, as are the triflate anions. NMR spectroscopy showed that the triflate ions remain associated with the complexes in CDCl 3 solution. Lanthanide‐induced shifts in the 19 F and 31 P NMR spectra confirm that one structure is present for all the lanthanides with an additional structure for the heavier metals. The acidity of the complexes was examined by 31 P NMR spectroscopic studies on the reactions between [Ln(H 2 O) 5 (Cy 3 PO) 2 ] · 2Cy 3 PO · (OTf) 3 (Ln = La, Eu, Er, Lu) and phosphines PR 3 (R = Ph, mesityl, Cy), Ph 2 PC 2 H 4 PPh 2 and Ph 2 PC 3 H 6 PPh 2 . Protonation of the more basic phosphines and H‐bonding to the less basic phosphines is observed.