Synthesis and Characterization of New Five-Coordinate Platinum Nitrosyl Derivatives: Density Functional Theory Study of Their Electronic Structure

 
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Synthesis and Characterization of New Five-Coordinate Platinum Nitrosyl Derivatives: Density Functional Theory Study of Their Electronic Structure (EN)

Ara, I. (EN)

Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας (EL)
Ara, I. (EN)

The neutral, five-coordinate platinum nitrosyl compounds [Pt(C6F5)3(L)(NO)] (2) [L=CNtBu (2"‰a), NC5H4Me-4 (2"‰b), PPhMe2 (2"‰c), PPh3 (2"‰d) and tht (2"‰e)] have been prepared by the reaction of [NBu4][Pt(C6F5)3(L)] (1) with NOClO4 in CH2Cl2. The ionic compound [N(PPh3)2][Pt(C6F5)4(NO)] (4) has been prepared in a similar way starting from the homoleptic species [N(PPh3)2]2[Pt(C6F5)4] (3). Compounds 2 and 4 are all diamagnetic with {PtNO}8 electronic configuration and show Ξ½(NO) stretching frequencies at around 1800 cmβ�’1. The crystal and molecular structures of 2"‰c and 4 have been established by X-ray diffraction methods. The coordination environment for the Pt center in both compounds can be described as square pyramidal (SPY-5). Bent nitrosyl coordination is observed in both cases with Pt-N-O angles of 120.1(6) and 130.2(7)Β° for 2"‰c and 4, respectively. The bonding mechanism of the nitrosyl ligand coordinated to various model [PtIIR4]2β�’ (R=H, Me, Cl, CN, C6F5 or C6Cl5) and [Pt(C6F5)3(L)]β�’ (L=CNMe, PH3) systems has been studied by density functional calculations at the B3LYP level of theory, using the SDD basis set. The R4Pt-NO and (C6F5)3(L)Pt-NO interactions generally involve two components: i) a direct Pt-NO bonding interaction and ii) multicenter-bonding interactions between the N atom of the NO ligand and the donor atoms of the R and L ligands. Moreover, with the more complex R groups, C6F5 or C6Cl5, a third component has been found to arise, which involves multicenter electrostatic interactions between the positively charged NO ligand and the negatively charged halo-substituents in the ortho-position of the C6X5 groups (X=F, Cl). The contribution of each component to the Pt[BOND]NO bonding in R4Pt[BOND]NO and (C6F5)3(L)Pt[BOND]NO compounds seems to be modulated by the electronic and steric effects of the R and L ligands. (EN)

density functional calculations (EN)

Πανεπιστήμιο Ιωαννίνων (EL)
University of Ioannina (EN)

Chemistry - A European Journal (EN)

Αγγλική γλώσσα

2003


WILEY-VCH Verlag (EN)



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