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4272058 
Journal Article 
Zerovalent Nickel Compounds Supported by 1,2-Bis(diphenylphosphino)benzene: Synthesis, Structures, and Catalytic Properties 
Neary, MC; Quinlivan, PJ; Parkin, G 
2018 
Yes 
Inorganic Chemistry
ISSN: 0020-1669
EISSN: 1520-510X 
57 
1 
374-391 
English 
29244503 
WOS:000419419700043 
Zerovalent nickel compounds which feature 1,2-bis(diphenylphosphino)benzene (dppbz) were obtained via the reactivity of dppbz towards Ni(PMe3)4, which affords sequentially (dppbz)Ni(PMe3)2and Ni(dppbz)2. Furthermore, the carbonyl derivatives (dppbz)Ni(PMe3)(CO) and (dppbz)Ni(CO)2may be obtained via the reaction of CO with (dppbz)Ni(PMe3)2. Other methods for the synthesis of these carbonyl compounds include (i) the formation of (dppbz)Ni(CO)2by the reaction of Ni(PPh3)2(CO)2with dppbz and (ii) the formation of (dppbz)Ni(PMe3)(CO) by the reaction of (dppbz)Ni(CO)2with PMe3. Comparison of the ν(CO) IR spectroscopic data for (dppbz)Ni(CO)2with other (diphosphine)Ni(CO)2compounds provides a means to evaluate the electronic nature of dppbz. Specifically, comparison with (dppe)Ni(CO)2indicates that the o-phenylene linker creates a slightly less electron donating ligand than does an ethylene linker. The steric impact of the dppbz ligand in relation to other diphosphine ligands has also been evaluated in terms of its buried volume (%Vbur) and steric maps. The nickel center of (dppbz)Ni(PMe3)2may be protonated by formic acid at room temperature to afford [(dppbz)Ni(PMe3)2H]+, but at elevated temperatures, effects catalytic release of H2from formic acid. Analogous studies with Ni(dppbz)2and Ni(PMe3)4indicate that the ability to protonate the nickel centers in these compounds increases in the sequence Ni(dppbz)2< (dppbz)Ni(PMe3)2< Ni(PMe3)4; correspondingly, the pKavalues of the protonated derivatives increase in the sequence [Ni(dppbz)2H]+< [(dppbz)Ni(PMe3)2H]+< [Ni(PMe3)4H]+. (dppbz)Ni(PMe3)2and Ni(PMe3)4also serve as catalysts for the formation of alkoxysilanes by (i) hydrosilylation of PhCHO by PhSiH3and Ph2SiH2and (ii) dehydrocoupling of PhCH2OH with PhSiH3and Ph2SiH2.