Tetrazoles, copper complexes

Infrared spectra have been recorded for the parent tetrazole (ttaH), its sodium salt, and a range of transition metal derivatives (94). In subsequent work the infrared spectra of sodium tetrazolate and of the copper complex Cu(tta)2 H20 were assigned and a vibrational analysis was reported for the tetrazolate anion (77). Infrared data have been... 

EPR data have been reported for 5-aryl tetrazolate salts of copper(II) values are in the range 2.12-2.15 and the gL and gy values are similar to those recorded for copper(II) complexes of other N donors. Related cobalt and nickel complexes gave complex or unresolved spectra (119). EPR data have been analyzed for the complex salts [Mn(l,5-pmtta)6][C104]2 and [Cu(l,5-pmtta) ][C104]2 (n — 4 and 6). For the copper complexes, copper and nitrogen hyperfine splittings were observed (118). 

Various N-alkylations of aliphatic, aromatic, and heterocyclic amines, tetrazoles, and phenylacridine-9"Carboxylate were also described. 21,122 -phe copper complex... 

Despite the weak basicity of isoxazoles, complexes of the parent methyl and phenyl derivatives with numerous metal ions such as copper, zinc, cobalt, etc. have been described (79AHC(25) 147). Many transition metal cations form complexes with Imidazoles the coordination number is four to six (70AHC(12)103). The chemistry of pyrazole complexes has been especially well studied and coordination compounds are known with thlazoles and 1,2,4-triazoles. Tetrazole anions also form good ligands for heavy metals (77AHC(21)323). 

Substituted tetrazoles readily exchange the 5-hydrogen for deuterium in aqueous solution. A major rate-enhancing effect is observed with copper(II) or zinc ions due to complexation with the heterocycle. The rate of base-induced proton-deuterium exchange of 1-methyltetrazole is 10 times faster than 2-methyltetrazole (77AHC(2l)323). 

Far infrared data have been reported and v(M-N) frequencies assigned for a variety of cobalt, nickel, copper, zinc, cadmium, and mercury tetrazolate complexes (153). An inverse relationship between the basicity of the tetrazolate anions and the values of v(M-N) has been interpreted as evidence of significant M - L n bonding (153). 

Recently, the structure was established for a whole series of copper) 11) complexes with 1-alkyl- and 1-aryltetrazoles l-(2-azidoethyl)tetrazole <2001AXEm335>, -tert-but ytetrazole <2002AXCm288>, l-(2,4,6-trimethylphenyl)tetra-zole <2003AXEml4>, 1-phenyltetrazole <2004AXCm368>, 1-ethyl- and 1-hexyltetrazoles <2005EJI1678>. 

Strongly luminescent, neutral copper(i) complexes bearing 5- 2-pyr-idyl)tetrazolate and various phosphine ligands have been studied. In particular, their photophysical properties have been compared to those of their cationic precursor complexes. While the cationic copper(i) precursors do not exceed photoluminescence quantum yields of 0.46, the new neutral species show quantum yields of up to 0.89 with efficient emission from mixed (ML + IL)CT states. ... 

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