A Hydrido η1-Alkynyl Diplatinum Complex Obtained from a Phosphinito Phosphanido Complex and Trimethylsilylacetylene

Abstract

The reaction of (trimethylsilyl)acetylene with the phosphinito phosphanido Pt(I) complex [(PHCy2)Pt(μ-PCy2){κ 2 P,O-μ-P(O)Cy2}Pt(PHCy2)](Pt-Pt) (1) results in the protonation of the Pt-Pt bond with the formation of the bridging hydride complex [(PHCy2)(Me3SiC≡C)Pt(μ-PCy2)(μ-H) Pt(PHCy2){κP-P(O)Cy2}](Pt-Pt) (2), which was characterized by spectroscopic, spectrometric and XRD analyses. Complex 2 exhibits in the solid state at 77 K a long-lived, weak, orange emission assigned as metal-metal to ligand charge transfer (MMLCT) (L = alkynyl) due to the presence of a very short Pt···Pt distance [2.8209(2) Å]. Reaction of 2 with etherate HBF4 results in the selective protonation of the phosphinito ligand to afford the species [(PHCy2)(Me3SiC≡C)Pt(μ-PCy2)(μ-H) Pt(PHCy2){κP-P(OH)Cy2}](Pt-Pt)[BF4] ([3]BF4).

Anionic phosph(in)ito (“phosphoryl”) ligands: Non-classical “actor” phosphane-type ligands in coordination chemistry

“…The reaction between the bridge  2 -P,O−phosphane oxide platinum(I) complex 106 bearing a Pt-Pt bond and an equimolar quantity of Brønsted acids HX led quantitatively to the synthesis of the corresponding   -P−phosphane oxide complex 107 (Scheme 36, [152]). …”

Uncovering Intramolecular π‐Type Hydrogen Bonds in Solution by NMR Spectroscopy and DFT Calculations

“…Complex 2 is the isolable intermediate of the reaction between 1 and (trimethylsilyl)acetylene, which ultimately affords the hydrido bridged complex 3 (Scheme ).…”

“…In the IR spectrum in KBr, complex 2 showed, besides the bands of P−H and PO−H stretches at 2280 and 3137 cm −1 , respectively, a very strong band at 2002 cm −1 attributable to the C≡C stretch of the σ‐bonded (trimethylsilyl)acetylide. This value is 40 cm −1 redshifted with respect to 3 ( ν =2042 cm −1 in KBr), indicating a lowering of the bond order in 2 with respect to 3 . A η 1 ‐coordination mode for the (trimethylsilyl)acetylide is also confirmed by the 13 C{ 1 H} NMR spectrum of 2 , which showed signals for the acetylenic carbons at δ =148.1 ppm (dd, 1 J C,Pt =1116 Hz, C 1 ) and δ =126.2 ppm (d, 2 J C,Pt =278 Hz, C 2 ) flanked by 195 Pt satellites characteristic of σ‐alkynyl ligands …”

“…We employed the same BP86 functional used for the geometry optimization and the basis set JCPL specifically developed for the calculation of spin–spin coupling constants in complexes with heavy metals . We preliminarily checked the adequacy of the computational protocol used for determining geometries, relative energies, and NMR properties of the complexes described herein, carrying out DFT calculations on 3 m (Figure S13 in the Supporting Information), the model of hydride complex 3 (the X‐ray structure of which is known) with methyl groups replacing the cyclohexyl groups. Results shown in Tables S1–3 and in Figures S13–15 (in the Supporting Information) indicate that the performance of the computational protocol is satisfactory.…”

“…In the courseo fo ur study on CÀHb ond activation by the phosphinito bridgedd iplatinum species[ (PHCy 2 )Pt(m-PCy 2 ){k 2 P, O-m-P(O)Cy 2 }Pt(PHCy 2 )](Pt-Pt) (1), we have isolated the s-acetylide complex [(PHCy 2 )(h 1 -Me 3 SiCC)Pt(m-PCy 2 )Pt(PHCy 2 ){kP-P(OH)Cy 2 }](Pt-Pt) (2). Complex 2 is the isolable intermediate of the reaction between 1 and( trimethylsilyl)acetylene, which ultimately affords the hydrido bridgedc omplex 3 [18] (Scheme 1).…”