Potentially Ambident Ligands

1 Cyanates, Thio- and Selenocyanates and Their Iso-analogues. - Table 15 gives a list of the vCN and vCS assignments proposed from the IR and Raman spectra of E(SCN)2, where E = Sr, Ba or The AT-coordinated NCS ligands in [Ru(Htcterpy)(NCS)3] , where tcterpy = 4,4, 4 -tricarb-oxy-2,2 6, 2 -terpyridine, have vCN at 2106 cm and vCS at 788 

The IR spectrum of Cu2( ii,i-NCO)2(NCO)2(phen)2 includes bands due to both terminal and bridging NCO ligands (VasNCO 2186, 2235 cm respectively)d The IR and Raman spectra of [Cu(pyza)2(NCS)2]n, where pyza = pyrazine-carboxamide, are consistent with the presence of end-to-end bridging NCS ligands.  

Raman spectroscopic data on the A1(III)-NCS -H20 system can be analysed on the basis of the formation of A1(NCS)(H20)5, A1(NCS)2(H20)4+ and two neutral, structurally different A1(NCS)3(H20)3 species. All of the complexes contain terminal, Af-bound NCS ligands.  

1 Cyanates, Thio- and Selenocyanates and their Iso-analogues - The Raman spectra of aqueous Mg(C104)2-NaSCN solutions were used to study the formation of magnesium thiocyanate complexes.  

The complex Re(NCO)3(PMe2Ph)3 has VasNCO bands at 2195, 2218 and 2238 cm with VgNCO at 1345 cm - all consistent with Re-N bonding. The IR and Raman spectra of [ReCl5(NCSe)] show -coordination of NCSe .  

Evidence has been presented for the formation of surface Cu-NCO species as intermediates in the reduction of NO by hydrocarbons with H2O on mordenite-type zeolite catalysts. The complex [Cu(NCS)(p-NCS)(Hmtpo)(H20)]2, where Hmtpo = 4, 7 -5-methyl-7-oxo[l,2,4]-triazolo-[l,5-a]pyrimidine, has VasNCO at 2144 and 2110 cm due to symmetric and asymmetric bridged thiocyanato groups respectively.  

A high-pressure Raman study of Zn(SCN)2 in DMSO shows that Zn(NCS)4 forms solvent-separated ion pairs at high pressures. The Raman spectra of Hg(SCN)2, [Hg(SCN)3]- and [Hg(SCN)4] in solution were related to the donor powers of the solvents.There is IR evidence for NCX (X = O, S or Se) complexes of thorium in ThCU solutions in acetone, methanol and DMF. In each case, coordination took place via 

---