114424-89-4Relevant academic research and scientific papers
Models for reactions of acetylene on platinum(111): A vinyl(acetylene)triplatinum complex and evidence for an ethylidyne intermediate
Rashidi, Mehdi,Puddephatt, Richard J.
, p. 1636 - 1641 (2008/10/08)
Reaction of [Pt3(μ3-H)(μ-dppm)3]+ (1) with excess acetylene gives [Pt3(CH=CH2)(μ3-η 2(∥)-HCCH)(μ-dppm)3]+, where dppm = Ph2PCH2PPh2. Deuterium-labeling studies indicate that H-D scrambling occurs within the vinyl group but not in the acetylene ligand. For example, [Pt3(μ3-D)(μ-dppm)3]+ with HCCH gave [Pt3(CH=CH2-d1)(μ3-η 2(∥)-HCCH)(μ-dppm)3]+, in which the deuterium label was distributed randomly in all three possible positions in the vinyl group. It is possible that this scrambling occurs by way of a short-lived ethylidyne intermediate. The complex is fluxional, due to rotation of the acetylene ligand, at room temperature. Similar reaction of 1 with excess propyne gives [Pt3(CH=CHMe)(μ3-η 2(∥)-MeCCH)(μ-dppm)3]+, but this complex is not fluxional at room temperature and is formed selectively by cis insertion of propyne into the Pt-H group. There is a strong resemblance to the chemistry resulting from chemisorption of acetylene on a Pt(111) surface, thus providing a clear example of the value of coordinatively unsaturated clusters as mimics of metal surfaces.
