Cleavage of a PN Bond in a Urea‐Containing (Ph2P(R)PPh2)‐Bridged Dinuclear Gold(I) Thiolate Complex by Fluoride and a Mechanistic Insight. Issue 23 (29th April 2015)

• Record Type: Journal Article
• Authors: He, Xiaoming; Lam, Wai Han; Cheng, Eddie Chung‐Chin; Yam, Vivian Wing‐Wah
• Is Part Of: Chemistry. Volume 21:Issue 23(2015)
• Page Start: 8447
• Page End: 8454
• Publication Date: 2015-04-29
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201500493
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>A urea‐containing, (Ph<sub>2</sub>P(R)PPh<sub>2</sub>)‐bridged, dinuclear, gold(I) thiolate complex, [Au<sub>2</sub>{Ph<sub>2</sub>PN(C<sub>6</sub>H<sub>4</sub>OMe‐4)PPh<sub>2</sub>}(SC<sub>6</sub>H<sub>4</sub>NHCONHC<sub>6</sub>H<sub>5</sub>)<sub>2</sub>] (<bold>1</bold>) was designed and synthesized and its photophysical and anion recognition properties studied. The results show that <bold>1</bold> has a high selectivity toward F<sup>−</sup>. Upon addition of F<sup>−</sup>, the yellow solution was decolorized, and drastic changes of emission and <sup>1</sup>H and <sup>31</sup>P{<sup>1</sup>H} NMR signals were observed. Interestingly, these changes are attributed to fluoride‐assisted PN bond hydrolysis, instead of the expected hydrogen‐bonding interactions with the urea receptor. Similar changes were observed for two other basic anions, AcO<sup>−</sup> and H<sub>2</sub>PO<sub>4</sub><sup>−</sup>, but to a much lesser extent; and these anions were found to bind to the urea receptor at the same time. On the other hand, Cl<sup>−</sup> was found to only bind to the urea moiety through hydrogen‐bonding interactions. Further studies with the control complex [Au<sub>2</sub>{Ph<sub>2</sub>PN(C<sub>6</sub>H<sub>4</sub>OMe‐4)PPh<sub>2</sub>}Cl<sub>2</sub>] (<bold>2</bold>) indicate that F<sup>−</sup> assists the hydrolysis process via cleavage of the PN bond. DFT calculations were performed to study the reaction mechanism for the fluoride‐assisted PN bond hydrolysis of <bold>2</bold>; these provide a better insight into the role of fluoride in the hydrolysis.</p> </abstract>