Structure Structure D 2000The Crystal Structure of Solvent-Free Silver Dodecachloro-closo-dodecaborate Ag 2 [B 12 Cl 12 ] from Aqueous Solution. -Colorless single crystals of the title compound are prepared by metathesis reaction of Cs 2 [B 12 Cl 12 ] with an aqueous solution of AgNO 3 . The compound crystallizes in the cubic space group Pa3 with Z = 4. The crystal structure is a distorted anti-CaF 2 type arrangement in which the quasi-icosahedral [B 12 Cl 12 ] 2anions are arranged in a cubic closest-packed fashion. The tetrahedral interstices are filled with Ag + cations which are strongly displaced from their ideal positions.

The complexes (bpym)PtCl(2) (1) and the new (micro-bpym)[PtCl(2)](2) (2), bpym = 2,2'-bipyrimidine, were synthesized and, in the case of 1, crystallized in solvent-free form for X-ray diffraction. The molecules 1 exhibit two different kinds of stacking motifs in the crystal with an interstack CH--N interaction. Complexes 1 and 2 were found to be sufficiently soluble for cyclic voltammetry, spectroscopy (absorption and emission), and spectroelectrochemical studies (UV-vis, EPR). As a result of single or double coordination of the strongly sigma-accepting [PtCl(2)] fragment to bpym, the paramagnetic anions 1(*)(-)() and 2(*)(-)() and the dianions 1(2-) and 2(2-) could be reversibly generated, despite the presence of metal-halide bonds. DFT calculations of A((195)Pt) and g tensor components confirm that the singly occupied MOs of the monoanionic species have mainly pi(bpym) character with nonnegligible platinum d orbital participation. The assignments of the electronic absorption and emission and resonance Raman spectra for both complexes are supported by DFT calculations.