om060335a_si_002.cif (28.73 kB)

Synthesis of Two Heterobimetallic Cluster Isomers [(η5-C5Me5)2Mo23-S)3S(CuI)2] and [(η5-C5Me5)2Mo23-S)4(CuI)2] from trans-[(η5-C5Me5)2Mo2(μ-S)2S2] and Their trans-to-cis Isomerization, Structures, and Third-Order NLO Properties

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posted on 28.08.2006, 00:00 by Zhi-Gang Ren, Hong-Xi Li, Guang-Fei Liu, Wen-Hua Zhang, Jian-Ping Lang, Yong Zhang, Ying-Lin Song
Reaction of trans-[(η5-C5Me5)2Mo2(μ-S)2S2] (1) with 2 equiv of CuI in CH2Cl2 at ambient temperature or in refluxing MeCN afforded two isomeric clusters, [(η5-C5Me5)2Mo23-S)3S(CuI)2] (2) and [(η5-C5Me5)2Mo23-S)4(CuI)2] (3). Compound 3 could also be prepared either by refluxing an acetonitrile solution of 2 or by heating 2 in the solid state at 120 °C. Compounds 2 and 3 were fully characterized by elemental analysis, IR, UV−vis, 1H NMR, ESI-MS, and single-crystal X-ray crystallography. The molecular structure of 2 consists of an incomplete cubane-like core in which the trans structure of 1 was retained, while that of 3 contains a cubane-like core in which the trans structure of 1 was converted into the cis structure. The trans-to-cis isomerization from 2 to 3 either in solution or in the solid state was explored by means of 1H NMR spectroscopy or X-ray powder diffraction. In addition, the third-order nonlinear optical (NLO) properties of 13 in CH2Cl2 were investigated by using the Z-scan technique. The hyperpolarizability γ values for the two isomers (5.65 × 10-30 esu (2) and 1.18 × 10-29 esu (3)) are larger than that of their cluster precursor 1 (3.07 × 10-30 esu).