om9b00425_si_002.xyz (4.05 kB)
E‑Selective Synthesis and Coordination Chemistry of Pyridine-Phosphaalkenes: Five Ligands Produce Four Distinct Types of Ru(II) Complexes
dataset
posted on 2019-08-22, 12:10 authored by Mika L. Nakashige, Jarin I. P. Loristo, Lesley S. Wong, Joshua R. Gurr, Timothy J. O’Donnell, Wesley Y. Yoshida, Arnold L. Rheingold, Russell P. Hughes, Matthew F. CainPyridine-phosphaalkene
(PN) ligands 2a–e were prepared in
an E-selective fashion
using phospha-Wittig methodology. Treatment of these five ligands,
varying only in their 6-substituent with RuCl2(PPh3)3, produced four distinct types of coordination
complexes: pyridine-phosphaalkene-derived 3b,d, cyclized 4e, and six-coordinate 5a and 6c. Prolonged heating of 3b,d in
THF resulted in C–H activation of the Mes* group and cyclization
to give 4b,d featuring a bidentate pyridine-phospholane
ligand bound to the metal center. Complex 5a, also possessing
a newly formed phospholane ring, contained a different spatial arrangement
of donors to Ru(II) with an agostic Ru–H–C interaction
serving as the sixth donor to the transition metal center. Ligands 2b,d,e and Ru(II) complexes 3b, 4b,e and 5a were all characterized
by X-ray crystallography. Six-coordinate 6c featured
a structure similar to 4b,d,e, but with the CF3 substituent acting as a weakly bound
sixth ligand to the Ru(II) center, as observed by 31P{1H} and 19F NMR spectroscopy. The calculated structure
of 6c established that the closest Ru- - -F
contact was at 2.978 Å.