Dinuclear platinum(II) complexes with bridging twofold deprotonated 2,2':6', 2''-terpyridne. New molecules with a 3,5-diplatinated-pyridil inner core: [Pt2(terpy-2H)(Me)(L2)], [Pt2(terpy-2H)(X)2(L)2] and [Pt2(terpy-2H)(H)2(L)2](L = neutral ligand; X = halide) - Crystal and molecular structure of [Pt2(terpy-2H)(Cl)2(PPh3)2]
Articolo
Data di Pubblicazione:
2006
Citazione:
Dinuclear platinum(II) complexes with bridging twofold deprotonated 2,2':6', 2''-terpyridne. New molecules with a 3,5-diplatinated-pyridil inner core: [Pt2(terpy-2H)(Me)(L2)], [Pt2(terpy-2H)(X)2(L)2] and [Pt2(terpy-2H)(H)2(L)2](L = neutral ligand; X = halide) - Crystal and molecular structure of [Pt2(terpy-2H)(Cl)2(PPh3)2] / S. Stoccoro, A. Zucca, G. L. Petretto, M. A. Cinellu, G. Minghetti, M. Manassero. - In: JOURNAL OF ORGANOMETALLIC CHEMISTRY. - ISSN 0022-328X. - 691:19(2006 Sep 15), pp. 4135-4146.
Abstract:
A series of dinuclear platinum complexes where the metal ions are linked by a twofold deprotonated 2,20
:60
,200-terpyridine (terpy) has
been synthesized. Reaction of cis-[Pt(Me)2(DMSO)2] with terpy in toluene at 90 C (molar ratio Pt:terpy 2:1) results in activation of the
C(3)- and C(5)–H bonds of the inner pyridinic ring to give the cyclometalated dinuclear derivative [Pt2(terpy-2H)(Me)2(DMSO)2] (1a),
(trans Me–Pt–N). From complex 1a, substitution of DMSO with neutral two-electron donors, L, allows isolation of a number of new
species [Pt2(terpy-2H)(Me)2(L)2] with the same N,C
C,N bridging ligand. The ‘‘Pt2(terpy-2H)’’ fragment is very robust: it is not affected
by alkylating reagents such as MeI or acids such as HPF6 or even HCl. Nevertheless the latter acid cleaves the Pt–Me bond affording
another series of complexes having a chloride in place of a methyl, [Pt2(terpy-2H)(Cl)2(L)2], (trans-Cl–Pt–C). The structure of complex 7,
[Pt2(terpy-2H)(Cl)2(PPh3)2], has been solved by X-ray analysis: the platinum atoms are in a tetrahedrally distorted square planar coordination.
The inner framework of the molecule is not flat: the dihedral angle between the best planes of the metal ions is 37.2(1). The
coordinated chlorides can be abstracted to give cationic solvento derivatives or exchanged with other anions such as iodides. Exchange
with [BH4]
allows to obtain the corresponding hydrides, examples of very rare C,N cyclometalated platinum(II) hydrides. Finally a two
step approach allows the synthesis of unsymmetric derivatives, [Pt2(terpy-2H)(Cl)2(L)(L0
)], with different ligands around each platinum
atom. The surprising deprotonation of terpy, typically a neutral ligand, points to the potential of the ‘‘Pt(Me)2’’ fragment in the intramolecular
C–H bond activation.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Crystal structure; Cyclometallated compounds; Nitrogen ligands; Platinum
Elenco autori:
S. Stoccoro, A. Zucca, G. L. Petretto, M. A. Cinellu, G. Minghetti, M. Manassero
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