132565-11-8Relevant articles and documents
Bismuth Compounds in Radical Catalysis: Transition Metal Bismuthanes Facilitate Thermally Induced Cycloisomerizations
Ramler, Jacqueline,Krummenacher, Ivo,Lichtenberg, Crispin
, p. 12924 - 12929 (2019)
The controlled radical chemistry of bismuth compounds is still in its infancy. Further developments are fueled by the properties of these complexes (e.g., low toxicity, high functional group tolerance, low homolytic bond dissociation energies, and reversible homolytic bond dissociations), which are highly attractive for applications in synthetic chemistry. Here we report the first catalytic application of transition metal bismuthanes (i.e. compounds with a Bi–TM bond; TM=transition metal). Using the catalyzed radical cyclo-isomerization of δ-iodo-olefins as a model reaction, characteristics complementary or superior to known B, Mn, Cu, Zn, Sn, and alkali metal reagents are demonstrated (including a different crucial intermediate), establishing transition metal bismuthanes as a new class of (pre-)catalysts for controlled radical reactions.
Syntheses and structures of the phenylbismuth/transition-metal carbonyl compounds [PPN][Ph2BiFe(CO)4], (Ph2Bi)2Fe(CO)4, [PhBiFe(CO)4]2, and Ph2BiMn(CO)5
Cassidy, Juanita M.,Whitmire, Kenton H.
, p. 2788 - 2795 (2008/10/08)
Treatment of Na2Fe(CO)4 with 1 equiv of Ph2BiCl in tetrahydrofuran (THF) affords Na[Ph2BiFe(CO)4], characterized as the [PPN]+ (PPN = bis(triphenylphosphine)nitrogen(1+)) salt ([PPN][I]); adding a second 1 equiv of Ph2BiCl produces (Ph2Bi)2Fe(CO)4 (II), which decomposes to [PhBiFe(CO)4]2 (III) in solution. III is also obtained in poor yield from the reaction of PhBiBr2 and Na2Fe(CO)4·3/2diox (diox = dioxane) in THF. The reduction of Ph2BiCl with 2 equiv of sodium in liquid NH3 followed by addition of Fe(CO)5 yields II and III along with traces of Ph4Bi2. I, II, and III·CH2Cl2 have been characterized by single-crystal X-ray diffraction. Crystals of [PPN][I] are monoclinic, Cc (No. 9), with a = 13.08 (1) A?, b = 15.832 (9) A?, c = 23.18 (1) A?, β = 99.53 (6)°, V = 4733 (6) A?3, and Z = 4. Convergence was achieved with R = 5.8% and Rw = 6.0% for 2584 observed reflections. The iron atom has a trigonal-bipyramidal coordination geometry with the pyramidal Ph2Bi group occupying an axial position. The Bi-Fe distance is 2.676 (4) A?. II crystallizes in the monoclinic space group P21/n (No. 14) with a = 12.009 (3) A?, b = 13.074 (2) A?, c = 17.264 (2) A?, β = 96.78 (1)°, V = 2691.5 (8) A?3, and Z = 4. The structure was refined to R = 5.0% and Rw = 5.8% for 3698 observed reflections. The octahedral Fe(CO)4 group in II is bonded to two Ph2Bi groups in cis positions. The average Bi-Fe distance in this compound is 2.828 (6) A?. III·CH2Cl2 crystallizes in the monoclinic crystal system, space group C2/c (No. 15) with a = 17.681 (6) A?, b = 7.069 (2) A?, c = 21.573 (10) A?, β = 101.19(3)°, V = 2645 (2) A?3, and Z = 4. The structure was refined to R = 4.2% and Rw = 4.9% for 1821 reflections with I > 3σ(I). The structure consists of a Bi2Fe2 planar parallelogram situated about an inversion center with an average Bi-Fe distance of 2.786 (3) A?. Each bismuth atom is bonded to one phenyl group. The iron carbonyl groups exhibit cis-pseudooctahedral coordination environments. The reaction of Ph2BiX (X = Cl, I) with Na[Mn(CO)5] produces octahedral Ph2BiMn(CO)5 (IV), which crystallizes in the triclinic space group P1 (No. 2) with a = 10.135 (4) A?, b = 13.484 (4) A?, c = 6.567 (4) A?, α = 99.11 (3)°, β = 92.53 (4)°, γ = 86.46 (2)°, V = 883.9 (6) A?3, Z = 2, R = 4.4%, and Rw = 5.6% for 2036 observed reflections. The Bi-Mn distance is 2.842 (2) A?.
