Palladium, dibromobis

Dibromo(l,5-cyclooctadiene)palladium(II) is an air-stable, orange solid. The compound is slightly soluble in solvents such as chloroform, nitrobenzene, and sulfolane (tetrahydrothio-phene 1,1-dioxide), and reacts rapidly with dimethyl sulfoxide to yield dibromobis(dimethyl sulfoxide)palladium(II). The p.m.r. spectrum of the compound in chloroform shows resonances at 3.58r for the olefinic protons and 7.40-r for the methylene protons. The infrared spectrum in Nujol has strong absorption maxima at 1472, 1417, 1333, 1172, 1083, 992, 905, 864, 823, 787, 764, 678, 310, 265, 221, 213, 178, and 126 cmr1. 

These results enabled us (34) to prepare several bridged compounds having two different metals. One of these was di-M-bromo-dibromobis(tri-n-propylarsine)mercury(II)palladium(II) (LXI), in which the palladium portion is of course planar and the mercuric portion is tetrahedral. 

Transition-metal induced [1,2]-rearrangement is also available to obtain phosphaalkyne 39. Dichlorophosphaethene 2a was allowed to react with an equivalent amount of tetrakis(triphenylphosphine)palladium(0) to afford phosphaalkyne 39 through intermediates (Scheme 21) [37]. The rearrangement process takes place in the reaction of dibromophosphaethene 2b with a small amount (0.2 equiv.) of dibromobis(triphenylphosphine)nickel(II) in the presence of zinc and tetraethylammonium iodide through the generation of a nick-el(0) intermediate [38]. Complex 43 was isolated in the reaction of 2a and tetrakis(triethylphosphine)platinum(0) which could afford phosphaalkyne 39 [27,28,39]. 

Purchased from Alfa Aesar, dibromobis(tri-ferf-butylphosphine)dipaUadium AA44446-77, purchased in 0.1-g quantities. This catalyst may also be named as palladium(I) tri-ferf-butylphosphine bromide, dimer by other suppliers, [Pd(f-Bu)3]PBr 2. 

CbHi N2NiS2 r Biacetylbis(mercaptoethylimine)nickel(II), 30B, 380 CgHi PdS4, Bis(S-ethylethene-1,2-dithiolato)palladium(II), 45B, 1289 CgHiuPtSft, Bis(S-ethylethene-1,2-dithiolato)platinum(II), 45B, 1289 CgHi6Br202PtS2 r trans-Dibromobis(1,4-oxathian)platinum(II), 43B,... 

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