16970-35-7Relevant academic research and scientific papers
Quantifying the electronic cis effect of phosphine, arsine and stibine ligands by use of rhodium(I) Vaska-type complexes
Otto, Stefanus,Roodt, Andreas
, p. 1 - 10 (2004)
The cis effects of phosphine, arsine and stibine ligands have been evaluated by measuring the IR stretching frequency in dichloromethane of the carbonyl ligand in a series of Rh(I) Vaska-type complexes, trans-[RhCl(CO)(L) 2]. These data were correlated with those obtained by Tolman for the electronic trans influences in the [Ni(L)(CO)3] complexes. The electronic contribution, χFc, of ferrocenyl was determined as 0. 8 from these plots by evaluating PPh2Fc as ligand. In order to accommodate arsine and stibine ligands an additional correction term, to compensate for differences in the donor atom, was added to Tolman's equation for calculation of the Tolman electronic parameter of phosphine ligands. In the resulting equation: ν(CONi)=2056.1+∑i=1 3χi+CL values for CL of C P=0, CAs=-1.5 and CSb=-3.1 are suggested for phosphine, arsine and stibine ligands, respectively. The crystal and molecular structures of trans-[RhCl(CO)(PPh2Fc)2]·2C 6H6, trans-[RhCl(CO){P(NMe2)3} 2] and trans-[RhCl(CO)(AsPh3)2] are reported. The Tolman cone angles for PPh2Fc and P(NMe2)3 were determined as 169° and 166°, while the effective cone angles for PPh2Fc, P(NMe2)3 and AsPh3 were determined as 171°, 168° and 147°, respectively.
α-cationic arsines: Synthesis, structure, reactivity, and applications
Dube, Jonathan W.,Zheng, Yiying,Thiel, Walter,Alcarazo, Manuel
supporting information, p. 6869 - 6877 (2016/06/14)
A series of structurally differentiated cationic arsines containing imidazolium, cyclopropenium, formamidinium, and pyridinium substituents have been synthesized through short and scalable routes. Evaluation of the donor properties of these compounds by IR spectroscopy and DFT calculations reveals similar σ-electron-releasing abilities for all of them; however, their π-acceptor properties are strongly influenced by the nature of the positively charged group. We describe the coordination chemistry of the newly prepared α-cationic arsines toward different metal centers and their reactivity in the presence of strong oxidants to afford cationic As(V) species. Their unique electronic properties have been exploited in Pt(II) catalysis to develop a new catalyst with remarkable activity in the cycloisomerization of enynes to trisubstituted cyclopropanes. To the best of our knowledge, this is the first report on the use of α-cationic arsine ligands in catalysis.
