Abstract. The crystal structures of yellow Cu 3 PS 4 and of black Cu 3 SbS 4 were refined from single crystal X-ray diffraction data. Cu 3 PS 4 crystallizes orthorhombic in an ordered wurtzite superstructure type with the space group

The local structures of the new phosphorus chalcogenide -copper iodide coordination compounds (CuI)P 4 Se 4 , (CuI) 2 P 8 Se 3 , (CuI) 3 P 4 Se 4 , and (CuI) 3 P 4 S 4 are investigated using comprehensive 63 Cu, 65 Cu, and 31 P magic angle spinning NMR techniques. Peak assignments are proposed on the basis of homo-and heteronuclear indirect spin-spin interactions, available from lineshape analysis and/or two-dimensional correlation spectroscopy. In particular, the 31 P-63,65 Cu scalar coupling constants have been extracted from detailed lineshape simulations of the 31 P resonances associated with the Cu-bonded P atoms. In addition, the RN n n pulse symmetry concept of Levitt and coworkers has been utilized for total through-bond correlation spectroscopy (TOBSY) of directly-bonded phosphorus species. The resonance assignments obtained facilitate a discussion of the 31 P and 63,65 Cu NMR Hamiltonian parameters in terms of the detailed local atomic environments. Analysis of the limited data set available for this group of closely related compounds offers the following conclusions: (1) bonding of a special phosphorus site in a given P 4 X n (X ¼ S, Se) molecule to Cu + ions shifts the corresponding 31 P NMR signal upfield by about 50 ppm relative to the uncomplexed molecule, (2) the magnitude of the corresponding scalar 31 P-63,65 Cu spin-spin coupling constant tends to decrease with increasing Cu-P distance, and (3) the 63,65 Cu nuclear electric quadrupolar coupling constants appear to be weakly correlated with the shear strain parameter specifying the degree of local distortion present in the four-coordinated [CuI 2 P 2 ] and [CuI 3 P] environments. Overall, the results illustrate the power and potential of advanced solid state NMR methodology to provide useful structural information in this class of materials.

Pure orange (CuI) 3 P 4 Se 4 was prepared by reaction of stoichiometric amounts of CuI, red P, and Se in evacuated silica ampules. The crystal structure was determined from single crystals at room temperature. (CuI) 3 P 4 Se 4 crystallizes in the hexagonal system, space group P6 3 cm with a ) 19.601(2) Å, c ) 6.7196(6) Å, and Z ) 6. The compound consists of -P 4 Se 4 cages that are embedded between columns of copper iodide. These columns can be considered as sections of a wurtzite-type structure, which is not yet known for copper iodide. Three of four phosphorus atoms are coordinated by copper, whereas selenium is exclusively bonded to phosphorus.

CuI) 3 P 4 S 4 is obtained by reaction of stoichiometric amounts of CuI, P, and S in evacuated silica ampoules. The yellow compound consists of monomeric b-P 4 S 4 cage molecules that are separated by hexagonal columns of CuI. (CuI) 3 P 4 S 4 crystallizes isotypic to (CuI) 3 P 4 Se 4 in the hexagonal system, space group P6 3 cm (no. 185) with a 19.082(3), c 6.691(1) ä, V 2109.9(6) ä 3 , and Z 6. Three of the four phosphorus atoms are bonded to copper, whereas no bonds between copper and sulfur are observed. The two crystallographically distinct copper sites are clearly differentiated by 65 Cu magicangle spinning (MAS) NMR spectroscopy. Furthermore, an unequivocal as-signment of the 31 P MAS-NMR spectra is possible on the basis of homo-and heteronuclear dipole ± dipole and scalar interactions. Dipolar coupling to the adjacent quadrupolar spins 63, 65 Cu generates a clear multiplet structure of the peaks attributable to P1 and P2, respectively. Furthermore, the utility of a newly developed two-dimensional NMR technique is illustrated to reveal direct connectivity between P atoms based on ( 31 P ± 31 P) scalar interactions.