Tetraanions

Triphosphorus anion Pj" (16e) was calculated to be linear [11]. Honea et al. [12] prepared and isolated Si (16e) by low-energy deposition into a solid nitrogen matrix, and carried out a Raman spectra study to show that Si is a planar rhombus The Al " tetraanion (16e) stabilized by the three LP ions in the most stable structure of LijAl " is rectangular in a capped octahedral arrangement [13],... 

The eight membered 2,4,6,8 rans-N4P4(NHC6Hn)4 could also be deprotonated to afford the tetraanionic derivatives (251). 

Several studies have addressed the cubic NLO properties of salts of heteropolymolybdate/ tungstate cluster anions.360,557-561 The tetraanion in a-H4SiW12O40,4HMPA,2H2O (HMPA= hexamethylphosphoramide) has a Keggin structure which has idealized Td point symmetry... 

The sodium atoms are both bound rf to one phospholide ring and 171 to the phosphorus atom of the other phospholide ring of the dianion. Each Na atom is further coordinated by one of the phosphole phosphorus atoms and two oxygen atoms of the DME coligand. The potassium complex is quite different reduction of the phosphole tetramer with 4 equiv of potassium yields a tetraanion, which, after crystallization from DME containing 18-crown-6, gives the solvent sepa-... 

The [Coi3(CO)24(C)2]4- tetraanion, which contains two carbide carbon... 

The trianion [Coi3(CO)24(C)2]3 has been isolated and its structure determined. In agreement with the electrochemical reversibility of the [Coi3(CO)24(C)2]4 /3 transformation, it maintains the structure of the tetraanion and the variations in bond distances are minimal. 

Recently, an inorganic promoter as [Ru(CN)5(Spy)]4 (Spy = 4-thio-pyridine) adsorbed on a gold electrode surface also proved to be very effective in the direct electrochemistry of cytochrome c the tetraanion not... 

For larger annulenes, even the reduction to tetraanions is possible [47, 75-77]. This is especially favorable for the neutral 4 + 2 species, which, after the injection of four electrons, reform a stabilized 4 + 2 jr-system. On the other hand, the existence of four excess charges in one molecule gives rise to strong electron repulsion. 

It can only be shielded by ion pairing that drives the formation of the tetraanion to a potential sufficiently positive for reduction to occur within the stability range of the solvent-electrolyte system. Thus, the electrochemical reduction of... 

The [(Fe5S6Xg)(M(CO)3)2] trianions are characterized by S=l/2 ground states and Aeir EPR spectra, Aat can be obtained only at temperatures <15 K resemble Ae spectra of the [(Fe6S5Xg)]3- "parent" prismanes (42). The corresponding tetraanions are EPR silent and possess Aamagnetic ground states. 

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