Pn+ cluster

Figure 7 Mo-Fe-S cluster consisting of the metal-sulfur connecting scheme akin to that in PN-cluster...

Figure 8 Structures of P-cluster. (a) Reduced form (PN-cluster) and (b) Oxidized form ( Pox-cluster )...

Uneven open shell Pn clusters are easier to ionize than even closed shell ones and the stability of the closed shell uneven P cluster cations is higher. For very large Pn+ cations with n = 25 + 8x (x — 0.1.2. 8) islands of stability were observed in the time of flight mass spectrum (TOF-MS) obtained by laser ablation of red phosphorus, suggesting that the more stable P clusters have connections with units of eight P atoms [71d]. A lot of effort has been put into the calculation of the most stable Pn+ cation structures. The respective global minimum structures of the more stable uneven P3+, Ps+, P71 and P<)h cluster cations are shown in Figure 2.6-10 [73, 74],... 

Cationic deltahedral Pn clusters are known for Pn=Bi. [Bis], [Big], and [Bi9], which have been structurally characterized with complex counterions such as AlCLt, AsFg, and HfCle , can be obtained either by molten salt routes or by using so-called super acidic systems [205-209]. According to Wade s formalism, [Bis] " " and [Big] correspond to 12 ske closo and 22 ske arachno structures, respectively, and the latter adopts the shape of a square antiprism. [Bi9] " which is expected to form a 22 ske nido-cluster in analogy to Fig. 2d, rather adopts a distorted tricapped trigonal prismatic topology (Fig. 2c). 

All other homoatomic Pn cluster anions are cage molecules with localized two-center-two-electron bonds. The cyclic [PnJ anion has been characterized by NMR spectroscopy for Pn = P [210], and structures are known for Pn = P, As, Sb, Bi (Table 2). A planar [Ps] anion has only been detected in solution by P NMR spectroscopy [210]. Envelop-shaped five- and six-membered rings are found for [Pns] and [Pe]", whereas [Asg]" deviates only slightly from planarity and has a chair conformation. The aromaticity of the planar anions [P4] and [Pe]" is distinct from that of regular 671-aromatic hydrocarbons and has been described... 

Zuo, J.L., H.C. Zhou, and R.H. Holm. 2003. Vanadium-iron-sulfur clusters containing the cubane-type [VFejSJ core unit Synthesis of a cluster with the topology of the PN cluster of nitrogenase. Inorg. Chem. 42 4624—4631. 

The double cubane [(Tp)2Mo2FegS8(PEt3)4] system has been investigated as model for the reactivity of the nitrogenase PN cluster. Four distinct processes for the conversion of double cubanes to PN-type clusters have been documented.89... 

Tp )WFe3S4Cl3] reacts with a system composed of excess Et3P, BH and HS yielding [(Tp )2W2Fe5S9Na(SH)(MeCN)]3 which exhibits a core topology similar to the PN cluster of nitrogenase.91... 

Hydroxide-promoted core conversions of molybdenum-iron-sulfur edge-bridged double cubanes Oxygen-ligated topological PN clusters... 

Karamanis, P., 8c Leszczynski, J. (2008d). Correlations between bonding, size, and second hyperpolarizability (y) of small semiconductor clusters ab initio study on Al Pn clusters with n = 2,... 

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