Adduct formation of [(η7-C7H7)Hf(η5-C5H5)] with isocyanides, phosphines and N-heterocyclic carbenes: An experimental and theoretical study

16-Electron cycloheptatrienyl zirconium allyl complexes

“…Selected bond lengths ( A) and angles ( ): ZreCht cent ¼ 1.731, Zre C Cht ¼ 2.337(2)e2.409(2), Zreallyl cent ¼ 2.290, ZreC8 ¼ 2.579(2), ZreC9 ¼ 2.475(2), complexes also provides some valuable information. In that case, À10.3 and À23.3 kcal mol À1 (for M05-2X) were found for the formation of the PMe 3 and IMe adduct, respectively [30]. This is at least 10 kcal mol À1 less than computed in the present case and illustrates the difference in ZreL bond strength in an 18-vs. a 16-electron cycloheptatrienyl zirconium complex.…”

“…The ZreC distances for the cycloheptatrienyl ligand fall in the range determined for related complexes [7], while the slight shortening of the ZreC bond to the central carbon atom of the allyl ligand in comparison to the terminal positions is in agreement with observations made for [(h 5 -C 5 Me 5 )Zr(h 3 -1,2,3-Me 3 C 3 H 2 )Br 2 ] (2.456 (11) vs. 2.513(15) A) [29]. Finally, the ZreP bond is at 2.7994(4) A somewhat shorter than in the 18-electron complexes [(h 7 -C 7 H 7 )Zr(h 5 -C 5 H 5 )(PMe 3 )] (2.8307(5) A) [30], [(h 7 -C 7 H 7 )Zr(h 5 -2,4-C 7 H 11 )(PMe 3 )] [32]. 4-(Dimethylamino)pyridine (DMAP) is a good nitrogen donor ligand, because the electron-donating amino functionality in the ortho-position enhances the nucleophilicity; the corresponding reaction with 1 also replaces THF, leading to [(h 7 -C 7 H 7 )Zr {h 3 -C 3 H 3 (TMS) 2 }(DMAP)] (3).…”

Coordination Chemistry of Disilylated Germylenes with Group 4 Metallocenes

“…A search for comparable group 4 metallocenes with coordinated NHCs surprisingly reveals only very few compounds. 37−39 However, all of these feature the NHC plane in the equatorial plane of the metallocene. Erker, Berke, and co-workers 37 found this behavior for group 4 metallocene cations.…”

Cycloheptatrienyl Zirconium Sandwich Complexes with Lewis Basic Phospholyl Ligands (Phosphatrozircenes): Synthesis, Structure, Bonding and Coordination Chemistry

“…[19,21] This behaviour can be put to good use to observe interesting secondary interactions in phosphane-functionalised complexes of the type [(h 7 -C 7 H 7 )M(h 5 -C 5 H 4 PR 2 )] (M = Zr, Hf) (Scheme 1). For instance, a complex with a weak ZrÀPd interaction was obtained, which was one of only a few earlylate heterobimetallic complexes consisting of neutral complex fragments.…”