Group 11 clusters

Reduction or disproportionation of univalent group 13 compounds generally resnlts in the formation of multiple-bonded species, clusters, and metals (eqnation 3). Such reactivity has been exploited for the prodnction of indium nanoparticles (y = 0) by the solvothermal decomposition of Cpln. Similarly, the thermal decomposition of many RM compounds (M = Al, Ga, In) results in the elimination of a portion of the substituents and produces metal-rich group 13 clusters of various sizes the clusters obtained are thonght to be intermediates on the pathway to the formation of bnlk metal. ... 

Group 13 clusters with electron counts less than the 2n - - 2 electrons corresponding to closo deltahedra have also been described. The classic examples of these are the boron subhalides, B C1 where n = 4, 8 -12 (and a more limited set of bromides and iodides), which have an electron count of 2n and are known as hypercloso clusters. These are based on the same closo structures expected for the 2n - - 2 electron clusters, namely, tetrahedral, dodecahedral, and tricapped trigonal prismatic for n = 4, 8, and 9. The 2n - - 2 dianions B C1 also show the expected deltahedral structures. The stability of the B C1 clusters has been attributed to a combination of the r-donor properties of the halides and steric effects. ... 

Scheme 3. Results of DFT(RI) calculations on trigonal-bipyramidal group 13 clusters. BP86 functional, SV(P) base SEN = shared electron number.

For example, the three NH bonding and three NH antibonding orbitals in NH3, when symmetry adapted within the C3V point group, cluster into ai and e mos as shown in the Figure below. The N-atom localized non-bonding lone pair orbital and the N-atom Is core orbital also belong to ai symmetry. 

Figure. 1. Schematic of essential components of the Exxon group cluster laser vaporization source and fast flow tube chemical reactor. On the far left is a 1 mm diameter pulsed nozzle that emits an -200 ysec long pulse of helium which achieves an average pressure of approximately one atmosphere above the sample rod. Immediately before the sample rod position the tube is expanded to 2 mm diameter. The length of this extender section can be varied form 6 mm to 50 mm depending upon the desired integration time for cluster growth. The reactor flow tube is 10 mm in diameter and typically 50 mm long. The reactants diluted in helium are added and mixed with the flow stream via the second pulsed valve.

I 7 Theory and Concepts in Main-Group Cluster Chemistry... 

According to McGrady (2004), however, a continuum view of the different types of clusters may be considered as illustrated in Fig. 4.27, which shows the relations between vertex count and electron count in main group clusters. 

Figure 4.27. Valence electron count and vertex count in main group clusters. Notice, according to McGrady (2004), that the different classes of clusters (electron-rich, electron-precise, etc.) simply occupy different domains in a continuum defined by the two variables (electron and vertex counts).

An Approach to the Bonding in Main Group Cluster Compounds... 

These calculations are encouraging for two reasons. First, they show that the first three spectra (alcohols) cluster closely with each other, as do the last three (chlorides). Second, the two groups cluster less well with each other than they do Internally. 

NOTE Full Dataset Full Dataset Cluster Group Cluster Group... 

The Number of Skeletal Bonding Electrons (v + x — 2) That Main Group Cluster Units Can Contribute... 

When surfactant molecules are dissolved in organic solvents, the head groups cluster together and the hydrocarbon chains point into the bulk phase, forming reverse micelles. If water is trapped in the area of the head groups, the system is termed a microemulsion. Sometimes, a short chain alcohol (e.g. hexanol) is added to aid dispersion. 

CARTY Phosphido-Bridged Iron Group Clusters... 

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