Synthesis, Structure, and Reactions of , Containing a Potentially Useful New Anion for Crystallizations

Article abstract of DOI:10.1021/ja00396a020

Stannous chloride reacts with yellow chlorohexakis(tert-butyl isocyanide)molybdenum(II) chloride to give the maroon complex ⁺, in which insertion of tin into the Mo-Cl bond has formally occurred.Crystals suitable for X-ray analysis were obtained by using the BBCN anion, <(Ph3B)2CN>^-, which may be viewed as an analogue of the PPN cation, <(Ph3P)2N>⁺.The seven-coordinate complex has crystallographically required C_S symmetry.Its geometry may be described as that of a C_S 4:3 piano stool or as that of a distorted capped octahedron with SnCl3^- as the capping ligand.The Mo-Sn bond length is 2.663(1) Angstroem, and the Mo-C distances vary from 2.071(18) to 2.138(8) Angstroem.The C<*>N group in the anion is disordered across a center of symmetry in the crystal lattice and has a bond length of 1.147(12) Angstroem.The sodium and tetramethylammonium salt of the BBCN anion have been synthesized.The compound <(Ph3B)2CN> crystallizes in the orthorhombic system, space group Pbcm, with a = 11.968(7) Angstroem, b = 23.012(6) Angstroem, c = 26.905(4) Angstroem, and Z = 4.Reaction of ⁺ with zinc on aqueous ethanol does not lead to reductive coupling of adjacent tert-butyl isocyanide ligands to form a coordinated N,N'-dialkyldiaminoacetylene, as in the reaction of zinc with other ⁺ complexes.Instead, the ²⁺ cation has been isolated from the reaction mixture as the tetraphenylborate salt.