66916-62-9Relevant academic research and scientific papers
ALKYNE COMPLEXES OF PLATINIUM. PART 4. STEPWISE FORMATION OF DI- AND TRI-PLATINIUM COMPLEXES WITH BRIDGING ALKYNE LIGANDS; CRYSTAL STRUCTURE OF
Boag, Neil M.,Green, Michael,Howard, Judith A. K.,Spencer, John L.,Stansfield, Robert F. D.,at all.
, p. 2182 - 2190 (2007/10/02)
Reaction of the compound with or (cod=cyclo-octa-1,5-diene) affords diplatinium complexes (R=Ph or Et).The triphenyl-phosphine compound has also been prepared by treating PhCCPh with .The terminal alkyne ligand in bonds a third platinium atom on treatment with to give the triplatinium complex .The latter can also be prepared by addition of 2 mol equivalents of to , and the triethylphosphine-triplatinium analogue is similarly obtained using .In view of the novelty of these compounds, a single-crystal X-ray diffraction study has been carried out on , crystals of which are monoclinic, space group C2/c (no. 15), with Z=4 in a unit cell of dimensions a=17.047 (2), b=13.667 (2), c=25.073 (3) Angstroem, and β=105.79(1)deg.The structure has been solved by heavy-atom methods from 3 038 intensity data =3.0?(I)> measured on a fourcircle diffractometer at 300 K, and refined to R 0.047 (R'0.046).The three platinium atoms adopt an open V-shaped configuration with an internuclear distance of 2.90 Angstroem and an interbond angle of 144deg, while the acetylenic units form transverse bridges across the two Pt-Pt vectors on the convex side of the V.The phenyl groups bend away from the metal atoms to give a C-C-Ph angle of 139deg, and the whole molecule is constrained crystallographically to C2 symmetry.The ethyl groups of the phosphine ligands are ill defined and possibly disordered.The diplatinium complexes (R=Ph or C6F5) have also been prepared, and characterised spectroscopically.Reaction of t)2> with yields trans-t)2(PPh3)2>>, scrambling of the CNBut and PPh3 ligands having occured.The stereochemistry of this complex, and its PhCC6H4OMe-4 analogue, has been established by 31P and 13C-labelling n.m.r. studies.The modes of formation of the various compounds are discussed.
