A Study of Through-Space and Through-Bond J(PP) Coupling in a Rigid Nonsymmetrical Bis(phosphine) and Its Metal Complexes

作者：Chalmers Brian A; Nejman Phillip S; Llewellyn Alice V; Felaar Adrian M; Griffiths Ben L; Portman Eden I; Gordon Emma Jane L; Fan Kenny J H; Woollins J Derek; Buhl M; Malkina Olga L; Cordes David B; Slawin Alexandra M Z; Kilian Petr^*

来源：Inorganic Chemistry, 2018, 57(6): 3387-3398.

DOI：10.1021/acs.inorgchem.8b00162

A series of representative late d-block metal complexes bearing a rigid bis(phosphine) ligand, iPr(2)P-Ace-PPh2 (L, Ace = acenaphthene-5,6-diyl), was prepared and fully characterized by various techniques, including multinuclear NMR and single-crystal X-ray diffraction. The heteroleptic nature of the peri-substituted ligand L allows for the direct observation of the J(PP) couplings in the P-31{H-1} NMR spectra. Magnitudes of J(PP) are correlated with the identity and geometry of the metal and the distortions of the ligand L. The forced overlap of the phosphine lone pairs due to the constraints imposed by the rigid acenaphthene skeleton in L results in a large (4)J(PP) of 180 Hz. Sequestration of the lone pairs, either via oxidation of the phosphine or via metal chelation, results in distinct changes in the magnitude of J(PP). For tetrahedral d(10) complexes ([LMCl2], M = Zn, Cd, Hg), the J(PP) is comparable to or larger than (193-309 Hz) that in free ligand L, although the P center dot center dot center dot P separation in these complexes is increased by ca. 0.4 angstrom (compare to free ligand L). The magnitude of J(PP) diminishes to 26-117 Hz in square planar d(8) complexes ([LMX2], M = Ni, Pd, Pt; X = Cl, Br) and the octahedral Mo-0 complex ([LMo(CO)(4)], 33 Hz). Coupling deformation density calculations indicate the through-space interaction dominates in free L, while in metal complexes the main coupling pathway is via the metal atom.

• 出版日期2018-3-19