Coordination compounds, fast-atom

The reactions of mercury(II) salts with oligo-amines afford informative examples for the fact that counterions induce the formation of a distinct complex or select a distinct complex in an equilibrium to crystallize with. Thus, Hg11 acetate with dien under exactly the same reaction conditions, in the presence of C104- or PF6-, yields the dinuclear complex [Hg2(dien)3](C104)4 or the mononuclear species [Hg(dien)(H20)](PF6)2, respectively, both characterized by IR, H, and 13C NMR spectrometries, by fast-atom bombardment (FAB) MS, cyclovoltammetry, and X-ray structure analyses.209 In the first compound Pna2, Z = 4), one Hg adopts five-coordination with one tridentate and one bidentate dien ligand, which with the remaining N-donor binds to the... 

Proton nmr titration experiments of [26] and [27] with KPF6 in acetonitrile revealed that in solution both compounds form 1 1 intramolecular sandwich complexes with the potassium cation. A number of alkyl-, vinyl- and azo-linked bis(benzo-15-crown-5) ligands are well known to exhibit this mode of K+ coordination. In the case of [26], a solid-state potassium complex was isolated whose elemental analysis and fast-atom bombardment mass spectrum ([26] K+ = 1083 complex ion) was in agreement with 1 1 complex stoichiometry (Fig. 20). 

Fast-atom bombardment spectroscopy, 28 1-22 applications to coordination compounds, 28 13-17... 

In conclusion, I hope that I have shown that fast-atom bombardment mass spectrometry is a potentially useful tool for the synthetic chemist working in many areas of inorganic, organometallic, and coordination chemistry. In addition, as further fundamental research is done in the field with these applications in mind, the technique should become as routine as IR or NMR. Combined with developments in high-resolution NMR of solids, FAB should provide particularly useful data on supported catalytic reactions. Certainly FAB and the other complementary mass spectrometric techniques, mentioned in less detail, constitute a major way of quickly characterizing new compounds. 

Miller, J.M. Fast Atom Bombardment Mass Spectrometry of Oiganometallic, Coordination, and Related Compounds. Mass Spectrom. Rev. 1989, 9, 319-347. 

Catalysis by coordination compounds also plays an important role in the field because high valent Fe and Mn 0x0 complexes can abstract a hydrogen atom from a C-H bond, leading to fast rebound of the newly formed OH group to the C radical to give the alcohol (Eq. 12.24),... 

The Zr and Hf tetrahydroborates M(BH4)4 are the most volatile compounds of these elements, with boiling points of 123 and 118°C they are also very sensitive to oxidation and hydrolysis. They can be obtained by the reaction of the chlorides with alkali metal borohydrides or of the complex fluorides NaMFs with aluminum borohydride (the fluorides MF4 do not react), followed by distillation from the reaction mixture. According to low-temperature X-ray data, all the borohydride groups are tridentate in both M(BH4)4 complexes, which have Td symmetry. The same is trae for their substituted M(BH3Me)4 derivatives, that is, the metal atom is 12-coordinate. Proton NMR indicates fast exchange of bridging and terminal protons on the NMR timescale in these fluxional molecules see Fluxional Molecule). 

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