Action of HCl upon the PtC bonds in [NBu4]2[Pt(C6Cl5)4] and [NBu4]2[trans-PtCl2(C6Cl5)2]: synthesis of tris(pentachlorophenyl), [NBu4] [Pt(C6Cl5)3L] and dichloro-monopentachlorophenyl-platinate(II), [NBu4] [PtCl2(C6Cl5)L], complexes