199396-21-9Relevant academic research and scientific papers
Nucleophilic addition to complexes of (Ph2P)2C=CH2 as a route to functionalized, redox-active ruthenium (II) - Diphosphine complexes
Barkley, Jim V.,Higgins, Simon J.,McCart, Mark K.,Pounds, Thomas J.
, p. 6188 - 6196 (1997)
The ligand (Ph2P)2C=CH2 (dppen) reacts with [RuCl2(PPh3)3] in CH2Cl2 to give trans-[RuCl2(dppen)2], 1. Complex 1 has reversible Ru(II)/Ru(III) electrochemistry, and on treatment with NOBF4, 1 affords [RuCl2(dppen)2]BF4, 1+. Refluxing solutions of 1 in chlorobenzene affords cis-[RuCl2(dppen)2], 2. With excess RNH2 in chlorobenzene or toluene, 1 reacts to give functionalized diphosphine complexes of general formula trans-[RuCl2({Ph2P}2CHCH2-NHR) 2] (R: PhCH2, 3a; [CH2]3NH2, 3b; n-octyl, 3c; R-α-CH(Me)Ph, 3d; [CH2]3Si(OEt)3, 3e) characterized principally by a small upfield shift in their 31P{1H} NMR spectra compared to that of 1 and by their distinctive 1H NMR spectra. Complex 3b·4MeOH crystallizes in the space group P1? with a = 11.448(6) A?, b = 13.10(1) A?, c = 11.178(7) A?, α = 93.16(6)°, β= 99.51(5)°, γ = 92.19(5)°, V = 1648(2) A?3, and Dcalcd = 1.250 g cm-3 for Z = 1. Complex 3e reacts with the surface hydroxyl groups of indium-doped tin oxide (ITO) electrodes, to give monolayers of anchored, redox-active Ru(II)-diphosphine complexes, characterized by cyclic voltammetry. The modified electrodes are stable to repetitive cycling over the Ru(II)/Ru(III) redox wave in acetonitrile -tetraethylammonium tetrafluoroborate and in aqueous buffer (pH 8). With anodized Pt electrodes, however, 3e reacts to form multilayers. Reaction of 1 with secondary amines is more sluggish than reaction with primary amines, and only adducts with pyrrolidine (3f) and morpholine (3g; impure) were isolated. With LiC≡C(CH2)3-CH3, 1 reacts to give trans-[Ru(C≡CR)2({Ph2P}2CHCH 2C≡CR)2] (R = n-butyl, 5); acetylide nucleophiles displace the chloride ligands as well as adding to the dppen double bonds of 1. Other carbanions fail to react with 1. The cis complex 2 reacts with a limited range of primary amines, to afford cis-[RuCl2({Ph2P}2CHCH2NHR) 2] (R: n-hexyl, 4a; [CH2]3Si[OEt]3, 4b). However, 4b was too insoluble for electrode derivatization. The half-sandwich complex [CpRuCl(dppen)] (6; Cp = η5-C5H5) also reacts with RNH2 to give [CpRuCl({PPh2}2CHCH2NHR)] (R: -[CH2]3NH2, 7a; -CH2Ph, 7b).
