Clusters hexameric

A characteristic reaction of sulfmylimines RNSO is the quantitative addition of R Li reagents to form adducts of the type Li[RNS(R )NR]. ° The structures of these sulfmimidinates are discussed in Section 10.4.4." The reactions of RNSO derivatives with two equivalents of lithium tert-butylamide result in the formation of diazasulfite anions [OSNR(N Bu)] (9.12) (Eq. 9.12)." The dilithium derivatives of these dianions form hexameric thirty-six atom (Lii2Ni206S6) clusters with structures that are dependent on the nature of the R group. 

Reaction of the primary phosphane Bu3SiPH2 If with MgBu2 furnishes the solvent-free hexameric cluster 17 (Eq. 10) (47). Yellow crystals, have been isolated in 39% yield, which are thermochromic. The NMR spectrum, especially the 31P NMR signal at S = -263.8, suggested that the molecule prefers a high symmetry or dissociates rapidly on the NMR time scale. Since 15 is highly soluble in aromatic hydrocarbons even at low temperature and free of metal oxide, it can thus be regarded as a valuable source of phosphandiide, that is, for nucleophilic RP2 transfer reactions. 

The transient (RPSn)221, which possibly represents a reactive intermediate during the synthesis of the hexameric Sn6P6 clusters 19c and 19d, has been trapped by the transformation of 20d in the presence of 2,3-dimethylbuta-l,3-diene, which solely gave 19d and the corresponding lff-l,l,-dichlorostannol (Eq. 14). 

The hexameric E3M3 clusters (M = Al, Ga E = P, As) 25a, 25c, and 25d comprise hexagonal prismatic E3M3 skeletons, as representatively shown for 25a in Fig. 25 (58). Thus, the cluster core resembles that of the Sn3P3 drums 19 (see Fig. 20), and the Al-As distances are only marginally longer than those in 27a. Apparently, the Al-H bonds are shielded by the bulky silyl groups, which hampered selective substitution reactions at the Al—H bond. 

Plavsic, Srzic and Klasinc performed a detailed electron impact mass spectrometric investigation of alkyllithium compounds . They have concluded that MeLi, /-PrLi, 5-BuLi and r-BuLi consist of tetrameric clusters only, while n-PrLi, n-BuLi and i-BuLi form mixtures of tetramers and hexamers, in the gas phase. Fast atom bombardment (FAB) mass spectrometry was used by Abdul-Sada, Greenway and Seddon to show that the extent of aggregation of f-BuLi is tetrameric while n-BuLi is hexameric (Table 1). Nevertheless, for both alkyllithium compounds the ion corresponding to (RLi)Li+ is the most abundant in the spectrum, as also shown in other studies of alkyllithium vapor. 

ESI mass spectra after the addition of 49 (or 50) to 51(PF6)2 show the hexameric clusters 51 (49)6 and 51 (50)6 as the dominating signals (Figure 3.24). These ions were irradiated in an infrared multiphoton dissociation experiment (I RMPD) with IR radiation from a C02 laser at different time intervals. The observed fragmentation behavior was exactly that expected for the hexameric capsule. 

Fig. 7.20. The hexameric model cluster used in calculations on zeolites (after Fri-piat et al., 1985 reproduced with the publisher s permission).

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