Geometries, Bonding Nature, and Relative Stabilities of Dinuclear Palladium(I) -Allyl and Mononuclear Palladium(II) 
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- 作者：Shigeyoshi Sakaki ; Kaori Takeuchi ; Manabu Sugimoto ; and Hideo Kurosawa
- 刊名：Organometallics
- 出版年：1997
- 出版时间：June 24, 1997
- 年：1997
- 卷：16
- 期：13
- 页码：2995 - 3003
- 全文大小：295K
- 年卷期：v.16,no.13(June 24, 1997)
- ISSN：1520-6041
文摘
MP2 optimization ofPd2(
-Br)(-C3H5)(PH3)2(1) andPdCl(
3-C3H5)(PH3)(2) well reproducesgeometrical characteristics of these complexes. For instance, theoptimized dihedral anglebetween 
-allyl and Pd2Br planes is 83
in1, and the dihedral angle between -allyl andPdCl(PH3) planes is 115 in 2. Theseoptimized values agree well with the experimentalresults (the deviation is less than 1). Although the -allylcoordinate bond of 2 is mainlyformed by donation from the -allyl nonbonding (n) orbital tothe unoccupied d orbital ofPd, the -allyl coordinate bond of 1 is formed byback-donation from the Pd-Pd d
bondingorbital to the -allyl * orbital and donation from the -allyln orbital to the Pd-Pd dantibonding orbital. To maximize these two interactions, twopalladium atoms take theirpositions under the terminal carbon atoms of -allyl group. Inaddition to these interactions,the back-donating interaction between the -allyl * and thePd-Pd d bonding orbitalsparticipates in the -allyl coordination. The dihedral angle 
of 1 decreases to 83 to enhancethe above-mentioned two back-bonding interactions. Introduction ofthe electron-withdrawing CN group to -allyl enhances the stability of 1 anddecreases the dihedral angle .However, introduction of the electron-releasing CH3group to -allyl little changes thedihedral angle of 1 but enhances the stability of2. These substituent effects, as well asthedifference in the dihedral angle between 1 and 2,are clearly interpreted in terms of thecoordinate bonding nature.
-Br)(-C3H5)(PH3)2(1) andPdCl(3-C3H5)(PH3)(2) well reproducesgeometrical characteristics of these complexes. For instance, theoptimized dihedral anglebetween -allyl and Pd2Br planes is 83 in1, and the dihedral angle between -allyl andPdCl(PH3) planes is 115 in 2. Theseoptimized values agree well with the experimentalresults (the deviation is less than 1). Although the -allylcoordinate bond of 2 is mainlyformed by donation from the -allyl nonbonding (n) orbital tothe unoccupied d orbital ofPd, the -allyl coordinate bond of 1 is formed byback-donation from the Pd-Pd d bondingorbital to the -allyl * orbital and donation from the -allyln orbital to the Pd-Pd dantibonding orbital. To maximize these two interactions, twopalladium atoms take theirpositions under the terminal carbon atoms of -allyl group. Inaddition to these interactions,the back-donating interaction between the -allyl * and thePd-Pd d bonding orbitalsparticipates in the -allyl coordination. The dihedral angle of 1 decreases to 83 to enhancethe above-mentioned two back-bonding interactions. Introduction ofthe electron-withdrawing CN group to -allyl enhances the stability of 1 anddecreases the dihedral angle .However, introduction of the electron-releasing CH3group to -allyl little changes thedihedral angle of 1 but enhances the stability of2. These substituent effects, as well asthedifference in the dihedral angle between 1 and 2,are clearly interpreted in terms of thecoordinate bonding nature.