On the relative stability of side-on and end-on coordination of dinitrogen to nickel (O): ”ab initio“ calculations on the model compounds [NiN2] and [Ni(PH3)2N2]

✍ Scribed by Giovanni Ciullo; Marzio Rosi; Antonio Sgamellotti; Carlo Floriani

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 559 KB
• Volume: 185
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(91)80254-u

✦ Synopsis

Ab initio" calculations have been performed on the systems NiN2 and Ni( PHz),N, to investigate the relative stability ofendon and side-on coordination of dinitrogen to Ni". The results indicate that both the x-back-donation and the reduction in the o repulsion are important factors in the description of the Ni-N, bonding. In NiN,, it is possible to reduce efficiently the repulsion by 4s polarization and the dinitrogen can come close enough to nickel in order to reach the best overlap in the K space for end-on coordination: this favors the end-on bonding aith respect to the side-on one. When ligands are present on both sides of nickel, 4s polarization is no longer possible and Nz cannot come close enough to nickel to allow the best overlap: this disfavors maihly the end-on coordination where a shorter r( Ni-N) is required and explains the preference for side-on coordination in Ni(PH3)ZN,