Distinguishing the Strength of Electronic Coupling for Mo2‐Containing Mixed‐Valence Compounds within the Class III Regime1. Issue 6 (12th December 2014)

• Record Type: Journal Article
• Authors: Cheng, Tao; Tan, Ying Ning; Zhang, Yu; Zhang, Yu Yu; Meng, Miao; Lei, Hao; Chen, Lu; Liu, Chun Y.
• Is Part Of: Chemistry. Volume 21:Issue 6(2015)
• Page Start: 2353
• Page End: 2357
• Publication Date: 2014-12-12
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201406196
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Two, symmetrical, mixed‐valence (MV), complex cations—{[Mo₂(DAniF)₃]₂(μ‐oxamidate)}⁺ (<bold>1</bold>⁺) and {Mo₂(DAniF)₃]₂(μ‐dithiooxamidate)}⁺ (<bold>2</bold>⁺; DAniF=<italic>N, N′</italic>‐di(<italic>p</italic>‐anisyl)formamidinate)—are significantly differentiated in terms of electronic coupling between the two [Mo₂] units. For <bold>1</bold>⁺ the intervalence (IV) charge‐transfer band in the near‐IR spectrum is truncated in half on the low‐energy side as predicted for MV compounds at the Class II–III limit (2<italic>H</italic>_ab/<italic>λ</italic>=1; for which <italic>H</italic>_ab=electronic coupling matrix element and <italic>λ</italic>=reorganization energy). In contrast, the very strongly coupled analogue <bold>2</bold>⁺, as indicated by 2<italic>H</italic>_ab/<italic>λ</italic>=3.5 (&gt; &gt;1), exhibits a higher energy and more symmetrical IV band. As rare examples, this pair of MV species shows distinct optical behaviors for MV systems crossing the Class III region. Optical analysis and DFT calculations are carried out to elucidate the transformation from vibronic to electronic vertical transition.</p> </abstract>