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Polyhydrides of Sc, Zr and Hf and Their Proposed Formation.
Author(s) -
Kurogi Takashi,
Kamitani Masahiro,
Carroll Patrick J.,
Mindiola Daniel J.
Publication year - 2017
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.201700062
Subject(s) - chemistry , phosphine , solid state , yield (engineering) , bridging (networking) , high pressure , pincer movement , medicinal chemistry , stereochemistry , catalysis , organic chemistry , computer network , materials science , engineering physics , computer science , engineering , metallurgy
Hydrogenation at 500 psi of (PNP)Sc(CH 3 ) 2 results in formation of a trinuclear polyhydride complex [(PNP)Sc] 3 (μ 2 ‐H) 4 (μ 3 ‐H) 2 ( 1 ) in 55 % yield. The solid‐state structure shows a non‐symmetric trinuclear species resulting from one pincer phosphine arm being demetallated, and where two hydrides bridge all three Sc centers, whereas the other four bridge two. Hydrogenation of (PNP)Zr(CH 3 ) 3 at 200 psi results instead in formation of a dinclear polyhydride species [(PNP)Zr(H)] 2 (μ 2 ‐H) 4 ( 2 ). Conducting the hydrogenation at atmospheric pressure, resulted instead in formation of the bridging methylidene complex [(PNP)Zr(CH 3 )] 2 (μ 2 ‐H) 2 (μ 2 ‐CH 2 ) ( 3 ), which cleanly converted to 2 , upon hydrogenation at higher pressure. Both 2 and 3 were also structurally characterized. Hydrogenation of (PNP)Hf(CH 3 ) 3 at 200 psi resulted in incomplete hydrogenation with some formation of dinuclear mono‐ and dimethyl‐polyhydride complexes [(PNP)Hf(CH 3 )] 2 (μ 2 ‐H) 4 ( 4 ) and [(PNP)Hf(CH 3 )][(PNP)Hf(H)](μ 2 ‐H) 4 ( 5 ), which were identified by solid‐state X‐ray structural studies. Based on these results, we propose a pathway for the complete hydrogenation of (PNP)Zr(CH 3 ) 3 to 2 .