1 research outputs found
Grandpa Bulbrook
A series of platinumÂ(II) complexes with the formulas
PtÂ(diimine)Â(pip<sub>2</sub>NCNH<sub>2</sub>)Â(L)<sup>2+</sup> [pip<sub>2</sub>NCNH<sub>2</sub><sup>+</sup> = 2,6-bisÂ(piperidiniummethyl)Âphenyl
cation; L
= Cl, Br, I, NCS, OCN, and NO<sub>2</sub>; diimine = 1,10-phenanthroline
(phen), 5-nitro-1,10-phenanthroline (NO<sub>2</sub>phen), and 5,5′-ditrifluoromethyl-2,2′-bipyridine
(dtfmbpy)] were prepared by the treatment of PtÂ(pip<sub>2</sub>NCN)ÂCl
with a silverÂ(I) salt followed by the addition of the diimine and
halide/pseudohalide under acidic conditions. Crystallographic data
as well as <sup>1</sup>H NMR spectra establish that the metal center
is bonded to a bidentate phenanthroline and a monodentate halide/pseudohalide.
The pip<sub>2</sub>NCNH<sub>2</sub><sup>+</sup> ligand with protonated
piperidyl groups is monodentate and bonded to the platinum through
the phenyl ring. Structural and spectroscopic data indicate that the
halide/pseudohalide group (L<sup>–</sup>) and the metal center
in PtÂ(phen)Â(pip<sub>2</sub>NCNH<sub>2</sub>)Â(L)<sup>2+</sup> behave
as Brønsted bases, forming intramolecular NH···L/NH···Pt
interactions involving the piperidinium groups. A close examination
of the 10 structures reported here reveals linear correlations between
N–H···Pt/L angles and H···Pt/L
distances. In most cases, the N–H bond is directed toward the
Pt–L bond, thereby giving the appearance that the proton bridges
the Pt and L groups. In contrast to observations for PtÂ(tpy)Â(pip<sub>2</sub>NCN)<sup>+</sup> (tpy = 2,2′;6′,2″-terpyridine),
the electrochemical oxidation of deprotonated adducts, PtÂ(diimine)Â(L)Â(pip<sub>2</sub>NCN), is chemically and electrochemically irreversible