I have been using Chloro ((tri-tert-butylphosphine)-2-(2-aminobiphenyl) palladium (II) as a catalyst and N,N-dicyclohexylmethylamine as base in Suzuki coupling a black sticky mass is getting formed in my vessel but when I use sodium tert-pentoxide as base in the reaction black sticky mass isn't forming, I did use H2SO4 and even HCl to dissolve the black sticky mass but I couldn't succeed but when I used 20% aq HBr the black sticky mass dissolved...Can someone kindly please say ASAP what would be the black sticky mass and why did it got dissolved only in Aq. HBr?