CORE
🇺🇦
make metadata, not war
Services
Services overview
Explore all CORE services
Access to raw data
API
Dataset
FastSync
Content discovery
Recommender
Discovery
OAI identifiers
OAI Resolver
Managing content
Dashboard
Bespoke contracts
Consultancy services
Support us
Support us
Membership
Sponsorship
Community governance
Advisory Board
Board of supporters
Research network
About
About us
Our mission
Team
Blog
FAQs
Contact us
(Amido)- and (Chlorido)titanium and -zirconium Complexes Coordinated by ansa-Bis(amidinate) Ligands with a Rigid o-Phenylene Linker
Authors
Cherkasov A.
Fukin G.
+7 more
Giambastiani G.
Luconi L.
Rossin A.
Shavyrin A.
Tolpygin A.
Trifonov A.
Tuci G.
Publication date
1 January 2017
Publisher
Abstract
© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimBis(amido)–TiIV and –ZrIV complexes stabilized by the bis(amidinate) ligands {C6H4-1,2-[NC(tBu)N(2,6-R2C6H3)]2}M(NMe2)2 [M = ZrIV, R = Me (3), R = iPr (4); M = TiIV, R = Me (5), R = iPr (6)] and {C6H4-1,2-[NC(tBu)N(2,6-Me2C6H3)]2}Zr(NMe2)3H (3·HNMe2) were prepared in fairly good yields by treating a (bis)amidine ligand C6H4-1,2-[NC(tBu)N(2,6-R2C6H3)H]2 [R = Me (1), iPr (2)] with an equimolar amount of the metal precursor M(NMe2)4 (M = ZrIV, TiIV). The salt metathesis reactions between equimolar amounts of the sodium amidinates C6H4-1,2-[NC(tBu)N(2,6-R2C6H3)]2Na2 and ZrCl4(thf)2 were also scrutinized to synthesize the corresponding ZrIV bis(amidinate) dichlorides {C6H4-1,2-[NC(tBu)N(2,6-R2C6H3)]2}ZrCl2 [R = Me (7), iPr (8)]. The coordination mode of the ligand to the MIV ions was strongly affected by the steric hindrance of the amidinate ligand (Me- vs. iPr-substituted aniline moieties) as well as by the nature of the ancillary groups bound to the metal center (NMe2 vs. Cl). The bis(amido) ligand with the 2,6-Me2C6H3 substituents at the amidinate nitrogen atoms coordinates to the zirconium ion in a tetradentate fashion both in solution and in the solid state (3 and 3·HNMe2). The compounds containing the bulkier 2,6-iPr2C6H3 units prefer a tridentate coordination mode (4). With the smaller TiIV ion, the bis(amidinate) ligands from this series are tridentate in the solid state (5 and 6), whereas they reversibly switch their denticity from tridentate to tetradentate (κ3 vs. κ4) in solution depending on the temperature. The ZrIV complex 4, featuring the bulkier bis(amidinate) ligand 2, shows a behavior similar to that of its TiIV analogue, that is, a tridentate ligand coordination in the solid state and a temperature-induced denticity change in solution. The standard thermodynamic parameters for the κ3/κ4 interconversions of the two model compounds 4 and 5 in [D8]toluene solution were determined from the respective linear van't Hoff plots. Finally, the ZrIV bis(chloride) complexes 7 and 8 invariably show a tetracoordinate mode for their bis(amidinate) ligands (1 and 2) in solution and in the solid state
Similar works
Full text
Open in the Core reader
Download PDF
Available Versions
Kazan Federal University Digital Repository
See this paper in CORE
Go to the repository landing page
Download from data provider
oai:dspace.kpfu.ru:net/114678
Last time updated on 07/05/2019
Kazan Federal University Digital Repository
See this paper in CORE
Go to the repository landing page
Download from data provider
oai:dspace.kpfu.ru:net/143701
Last time updated on 07/05/2019