两种单齿硫醇为配位体的钼络合物的合成和结构表征

本文报导利用MoC1_5、NaOMe、C_6H_5CH_2SH和NaHS在无氧、无水,室温条件下在甲醇介质中合成(Et_4N)_2Mo_2O_2S_2(SCH_2C_6H_5)_4](化合物Ⅰ)和(Et_4N)-Mo_2O_2(μ-SCH_2C_6H_5)_3(SCH_2C_6H_5)_4](化合物Ⅱ)的反应条件,分离步骤。本文同时报导这两种化合物的核磁共振谱、红外光谱、电子光谱等结构表征,同时也对化合物形成的可能机理作了探索性的讨论。

Synthesis and Characterization of Two Bis-(oxomolybdenm (V) sulfur) Compounds with Monodentate Ligand

At room temperature under anaerobic and anhydrous conditions, MoCl5, NaOMe, C6H5CH2SH and NaSH react in methanol solution and form a reddish-brown solution. The products are precipitated with Et4NI. After carefull separation and recrystallization, we haveobtained two compounds: (Et4N)2Mo2O2(μ-S)2(SCH2C6H5)4](I) and (Et4N0Mo2O2(μ-SCH2C6H5)3(SCH2C6H5)4](II).Compound (I) is light orange in color and decomposes at 200O C. Anal, calcd. for C44H68Mo2N2S6O2: C, 50.79; H, 6.54; Mo, 18.46;S, 18.46; N, 2.69. Found: C, 51.27; H, 6.53; Mo, 18.37; S, 17.46; N, 2.48.Compound (II) is red in color and decomposes at 145 C. Anal. calcd. for C57H69Mo2NS7O2: C, 56.28; H, 5.72; N, 1.15; Mo, 15.77; S, 18.45. Found: C, 55.77; H, 5.71; N, 0.97; Mo, 15.76; S, 17.61.By differential thermal analysis, both compounds show exothermal change before the decomposition point. Exothermal change of (I) occurs at 158O C whereas that of (II) around 135O C.Infrared spectra of both compounds are very similar and indicate that Mo atoms bind with oxygen and mercaptan. There are,however, several differences between the two: Mo=O vibration of (II)(914cm-1 ) is red shifted in comparison with that of (I) (942cm-1 );the bridge vibration of (II) (470cm-1 ) is blue shifted with respect to (I) (461cm-1 ); in the Mo-S vibration region (300-400cm-1 ), (II) has three absorption peaks , while (I) has only one, Magnetic susceptibility of both compounds has been measured and diamagnetic contribution subtracted from the total suscepbi-lity: cgs in compound (I) and cgs in (II) .No ESR signal has been observedin solid state or in CH3CN solution, but both compounds, in 6NHCl solution, give a characteristic MpOCl52- signal (g=1.946,A=50G at room temperature and g = 1.965, g =1.942 at 77 K).Moreover both compounds have been studied by 1H NMR (100 MHz and 360 MHz): (I) gives chemical shifts at 1.1 (24H, t, C-CH3); 3.1 (16H,q, C-CH2-N); 4.7 (8H, s, C-CH2S) and 7.0-7.6 (20H, m, C6H5- ) ppm; (II) at 1.1 (12H, t, CH3-C); 3.2 (8H, q, C-CH2-N); 4.3-4.8 (14H, m, C-CH2-S) and 6.9-7.5 (35H, m, C6H5-C) ppm. Thesedata suggest that the ratio of (Et4N): (CH2C6H5) is 2:4 for (I)and 1:7 for (II), and that SCH2C6H5 ligands in (II) are of twodifferent magnetic types. Mo-Mo has d1 -d1 antiferromagnetic coupling and each molecule shows diamagnetic properties. Mechanism of reaction is also discussed.