Oxidative Addition of Halogens to Homoleptic Perfluoromethyl or Perfluorophenyl Derivatives of Platinum(II): A Comparative Study (Journal article)

Menjon, B./ Martinez-Salvador, S./ Gomez-Saso, M. A./ Fornies, J./ Falvello, L. R./ Martin, A./ Tsipis, A.

The equilibrium geometries of the homoleptic perfluorinated organoplatinate(II) anions [Pt(CF(3))(4)](2-) and [Pt(C(6)F(5))(4)](2-) have been computed at the B3P86/LANL2DZ level of theory. Remarkably good agreement with the experimentally determined structures has been obtained by X-ray diffraction methods. The reactivity of [NBu(4)](2)[Pt(CF(3))(4)] (1) towards halogens (Cl(2), Br(2), and I(2)) has been investigated by using a combined experimental and theoretical approach. The perfluoromethyl derivative 1. has been found to undergo clean oxidative addition of the three halogens under investigation, giving rise to [NBu(4)](2)[trans-Pt(CF(3))(4)X(2)] (X = Cl (7), Br (10), I (13)) in a quantitative and stereoselective way. In the low-temperature reaction of the perfluorophenyl derivative [NBu(4)](2)[Pt(C(6)F(5))(4)] (3) with Cl(2) or Br(2), the corresponding oxidative-addition products [NBu(4)](2)[trans-Pt (C(6)F(5))(4)X(2)] (X = Cl (14), Br (15)) can also be obtained. In the case in which X = Br and working in CHCl(3) at -55 degrees C. it has been possible to detect the formation of an intermediate species to which we assign the formula [trans-Pt(C(6)F(5))(4)Br(ClCHCl(2))](-) (16). The solvento complex 16 is thermally unstable and prone to undergo reductive elimination Of C(6)F(5)-C(6)F(5). In the presence of PhCN, complex [NBu(4)][trans-Pt(C(6)F(5))(4)Br(NCPh)] (17) was isolated and structurally characterized. The reaction of 3 with I(2) gave no organoplatinum(IV) compound. Our comparative study reveals that the CF(3) group is especially suited to stabilize organometallic compounds in high oxidation states. This ability can be attributed to a combination of factors: its hardness, its high group electronegativity, its small size, and its reluctance to undergo reductive elimination processes.
Institution and School/Department of submitter: Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας
Keywords: density functional calculations,halogens,homoleptic compounds,oxidation,platinum,transition-metal-complexes,h bond activation,weakly coordinating anions,ortho-perfluoroalkyl groups,density-functional theory,x-ray-structure,reductive elimination,molecular-structures,electronic-structure,fluorocarbon derivatives
URI: http://olympias.lib.uoi.gr/jspui/handle/123456789/8728
ISSN: 0947-6539
Link: <Go to ISI>://000267721500010
Appears in Collections:Άρθρα σε επιστημονικά περιοδικά ( Ανοικτά)

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