Microwave spectra and theoretical calculations for two structural isomers of methylmanganese pentacarbonyl
Microwave spectra and theoretical calculations for two structural isomers of methylmanganese pentacarbonyl
复制标题
五羰基甲基锰的两种结构异构体的微波谱及理论计算
DOI：
10.1021/acs.inorgchem.0c00524
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发表时间：
2020
影响因子：
4.6
通讯作者：
Kukolich, S.
中科院分区：
文献类型：
--
作者：
Tanjaroon, C.;Zhou, Z.;Mills, D.;Keck, K.;Kukolich, S.
用脉冲束傅里叶变换微波光谱仪测量了五羰基甲基锰两种结构异构体在4 - 9 GHz波段的第一微波转动光谱。两个异构体，一个非对称的顶部酰基异构体的结构，光谱进行拟合，以获得旋转和离心畸变常数和55 Mn四极耦合参数。对称的CH 3 Mn（CO）5的转动常数、锰（55 Mn）核四极耦合常数、离心畸变常数和自旋-转动常数被测定，其值如下：A = B = 793.153（3）MHz，DJ = 0.00040（4）MHz，DJK = 0.0018（2）MHz，Ccc = 0.183（6）MHz，eQqcc = − 87.4（3）MHz。测定了酰基-CH_3C（O）Mn（CO）_4的转动常数和~（55）Mn四重偶合常数，其值分别为：A = 839.96（4）MHz，B = 774.20（7）MHz，C = 625.63（1）MHz，1.5 eQqaa = 44.9（47）MHz和0.25（eQqbb-eQqcc）= 11.9（12）MHz.对酰基-CH_3C（O）Mn（CO）_4异构体的转动常数进行了测定，并与各种理论计算值进行了比较。计算出的二触酰基和触酰基结构的旋转常数与实验值相当接近。我们注意到，计算的双半酰基结构与实验数据最接近，因为使用aug-cc-pVDZ基组的B3LYP泛函计算的双半酰基结构与A，B和C的实验值接近。
The first microwave rotational spectra for two structural isomers of methylmanganese pentacarbonyl were measured in the 4–9 GHz range using a pulsed-beam Fourier transform microwave spectrometer. The spectra for the two isomers, a symmetric-top structure and an asymmetric-top acyl isomeric structure, were fit to obtain rotational and centrifugal distortion constants and55Mn quadrupole coupling parameters. The rotational constants, the manganese (55Mn) nuclear quadrupole coupling constant, the centrifugal distortion constants, and the spin–rotation constant were determined for the symmetric CH3Mn(CO)5and have the following values:A=B= 793.153(3) MHz,DJ= 0.00040(4) MHz,DJK= 0.0018(2) MHz,Ccc= 0.183(6) MHz, and eQqcc= −87.4(3) MHz. Rotational constants and55Mn quadruple coupling constants were determined for the isomeric acyl-CH3C(O)Mn(CO)4and have the following values:A= 839.96(4) MHz,B= 774.20(7) MHz,C= 625.63(1) MHz, and 1.5 eQqaa= 44.9(47) MHz and 0.25(eQqbb– eQqcc) = 11.9(12) MHz. The measured rotational constants from the isomeric acyl-CH3C(O)Mn(CO)4were compared with various theoretical computations. The calculated rotational constants for the dihapto-acyl and the agostic-acyl structures are reasonably close to the experimental values. We note that the calculated dihapto-acyl structure most closely matches the experimental data, as the calculation for the dihapto structure using the B3LYP functional with the aug-cc-pVDZ basis set closely reproduced the experimental values forA,B, andC.