Stereoelectronic properties of metalloenzymes. 4. Bis(imidotetraphenyldithiodiphosphino-S,S')copper(II) as a tetrahedral model for type I copper(II)

Blue copper proteins: Synthesis, spectra, and structures of Cu I N 3 (SR) and Cu II N 3 (SR) active site analogues

“…2). The Cu-S distance of 2.19(1) A and Cu-N distances of 2.00(2)-2.10(2) A are comparable with values reported for other Cu(I) structures (25)(26)(27)(28)(29)(30)32). Spectral data (see below) lead us to assign a similar, monomeric structure to the dark-blue Cu"l analogues.…”

Copper(I) Complexes with a Cu4S6‐ and CuS4‐Type Core Obtained from the Reaction of Copper(0) with HN(SPPh2)2·I2

“…EXAFS data for CuAce1 and CuMac1 [6b] suggests the presence of a distorted tetranuclear copper cluster; the Cu I ions are trigonally coordinated with Cu-S distances of about 2.25 Å and a Cu-Cu distance of 2.7 and 2.9 Å when two different Cu···Cu interactions were considered (Table 3). In this context, the Cu 4 S 6 core in the cation [Cu 4 (L) 3 ] + might represent a useful model compound for the metal centres in CuAce1 and CuMac1, since the mean Cu-S and Cu-Cu bond lengths (Table 3) compare well with those reported for these clusters. Moreover, unlike the copper thiolate model compound [11] [Cu 4 2.261 (6) [a] Number of Cu-Cu and Cu-S interactions of specified distance for each copper atom.…”

“…Furthermore, the ability of L to form a tetrahedral CuS 4 core with the Cu II ion has been used by Bereman et al [3] to propose the complex [Cu(L) 2 ] as a potential model for type-I Cu II sites in metalloenzymes; unfortunately, the complex was not stable for more than a few days at room tempera- form a slightly distorted tetrahedral CuS 4 core. The 31 P NMR spectroscopic data of compound 1 are consistent with the maintenance of its structure in solution.…”

“…Moreover, phosphorus variable-temperature measurements indicate a change from a two-spin coupled AB system at 0°C to an A 2 spin system at 40°C. The reaction of [Cu 4 (L) 3 ] + with HI, monitored by 31 P NMR spectroscopy, leads to the protonation of the complexed ligands at the Cu 4 core and formation of the cation [Cu 4 (HL) 3 ] 4+ . The protonation reaction is reversible: increasing the amount of organic base 1, 8- [4] The X-ray crystal structures of these complexes revealed that the molecules contain a six-membered Cu I 3 S 3 ring in their core, with each copper atom being tricoordinate in an approximately trigonal geometry resulting from the coordination of one terminal and two bridging S-donors.…”

Novel usage of palladium complexes with P-N-P ligands as catalysts for diphenyl carbonate synthesis

“…The starting materials Ph 2 PNHPPh 2 , Ph 2 P(S)NHP(S)Ph 2 and Ph 2 P(Se)NHP(Se)Ph 2 were prepared according to the literature methods. [22][23][24] The solvents were distilled and stored in activated 3 Å molecular sieves before use. 3 Å molecular sieves were activated by heating at 350°C under nitrogen for 10 h.…”