posted on 2012-04-09, 00:00authored byAlmas
I. Zayya, John L. Spencer
The coordination chemistry of the PN bicyclic ligand
7-tert-butyl-1,5-bis(carbomethoxy)-6,8-bis(p-dimethylaminophenyl)-3-methyl-3-aza-7-phosphabicyclo[3.3.1]nonan-9-one
(1) was explored with rhodium, palladium and platinum,
and a wide range of complexes were synthesized, including [ML2(1)] (M = Pd, Pt; L = Cl, Me), [ML(1)] (M = Rh, Pd, Pt; L = C2H4, cycloocta-1,5-diene
(cod), norborn-2-ene (nb)) and [PtL(1)]CH(SO2CF3)2 (L = 1-σ,4–5-η-C8H13, 1–3-η-C8H13). Cycloplatination at the ortho positions of the 6,8-bis(dimethylaminophenyl)
substituents led to the formation of [Pt(C2H4)(1-2H)] and [Pt(1–3-η-C8H13)(1-H)]. Further reaction of [Pt(C2H4)(1-2H)] yielded the trans- and cis-hydroxo-bridged
dimers [Pt2(μ-OH)2(1-H)2]. The nitrogen donor atom is not coordinated to the platinum
metal center in the cyclometalated PN complexes. Protonation of [Pt(nb)(1)] with CH2(SO2CF3)2 produced [PtH{CH(SO2CF3)2}(1)]. Similarly, protonation of [Pt(nb)(1)] with CHPh(SO2CF3)2 gave the norbornyl
agostic complex [Pt(η2-C7H11)(1)]CPh(SO2CF3)2,
as confirmed by X-ray crystallography. PN metal complexes in which
the central carbonyl group was hydrated to a geminal diol were also
observed. 15N NMR data, obtained from 1H–15N HMBC experiments, showed no explicit relationship between
the coordination mode of the nitrogen group in 1 and
the 15N chemical shift.