Phosphorus cluster anions

The PACIS has been used to generate phosphorus cluster anions P,T up to n = 9. Photoelectron spectra recorded at photon energies hv = 2.33 eV, 3.49 eV, and 4.66 eV are shown in Figs. 8, 9a, and 9b, respectively. The spectra of PJ show four electronic transitions (Fig. 9b, A-D), and feature A is assigned to the ground state transition (VDE 0.68 + 0.05 eV). Vibrational fine structure is... 

Fig 28. Vanadium borophosphates with the composition [(VO)2BP20io] n form cage-like cluster anions, which may be empty (107, n = 4) or centered by a cation (109, n = 6). For clarity only half of the vanadium and phosphorus atoms of the cluster anions are shown... 

In a series of papers, metal sulfide cluster anions of first-row transition metals, principally copper, have been reacted with a variety of reagents including thiols, sulfur, phosphorus, and phosphines (99, 145, 256, 257). 

The octaruthenium phosphide cluster anion [Ru8(/t8-P)(/i-CO)2(CO)2o] 310 is produced in around 30% yield from the thermolysis of Ru3(jU-H)(/i-NCsH4)(CO)io and chlorodiphenylphosphine in chlorobenzene. The square-antipris-matic cluster contains an interstitial phosphorus atom (5p 600-800), and 114 c.v.e., four electrons less than expected. Cyclic voltammetric studies show an uptake of four electrons in three steps the third two-electron reduction step is irreversible, suggesting that a structural change may occur. 

A new, exciton-like mechanism has been proposed by Demidenko et al. [34] to describe the formation of amorphous NiP films. According to these authors, the electroless process is initiated by the reduction of Ni2 + by adsorbed hydrogen to produce clusters of pure Ni. Vacancy sites on these clusters capture a proton (presumably from the H2POJ anion) to form an exciton-like state, which subsequently captures more Ni atoms, and so on. Phosphorus can be captured and fixed at a vacancy site. 

The 12 RP fragments cap alternately the Cu4 faces of the Cu24 polyhedron, resulting in fivefold-coordinated phosphorus atoms. This structure resembles that of the recently described [Cu24(NPh)i4]4 anionic cluster (40). The Cu-P and Si-P distances are unremarkable. The construction principle of parallel Cu layers to form a metal-like package has also been observed for other Cu clusters (41). The main reason for the different structures of Cu2PR and Li2PR clusters is the covalent character of the Cu-P bond, with the additional involvement of favorable Cu-Cu interactions. The latter are probably due to relativistic d10-d10 interactions (dispersion-type of interaction) (42, 43). 

The intermetallic phase [26] Na2Tl illustrates a simple application of the Zintl-Klemm concept to a group 13 metal cluster. Complete electron transfer from Na to T1 leads to the (Na" )2Tl formulation. The Tl dianion is isoelectronic with group 15 elements and thus should form similar tetrahedral structures with six two-center two-electron bonds along the edges of the tetrahedron. Indeed, the Tl anions in the Na2Tl phase form Tl4 tetrahedra, similar to the isoelectronic P4 and As4 units in white phosphorus and yellow arsenic. 

There is much interest in transition-metal carbonyl clusters containing interstitial (or semi-interstitial) atoms in view of the fact that insertion of the encapsulated atom inside the metallic cage increases the number of valence electrons but leaves the molecular geometry essentially unperturbed. The clusters are generally anionic, and the most common interstitial heteroatoms are carbon, nitrogen, and phosphorus. Some representative examples are displayed in Fig. 19.4.3. 

Although the products are written as simple ionic binary compounds, it is known that complex materials containing anions that consist of polyhedral species containing the nonmetal are also produced. For example, a P73- cluster is known, which has six of the phosphorus atoms arranged in a trigonal prism with the seventh occupying a position above the triangular face on one end of the prism. 

Table 25.2.2 BDEs in Phosphorus-Anion Clusters/Complexes ...

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