Manganese cationic pyrazolylamidino complexes

The reactions of fac-[MnBr(CO)3(NHC(CH3)pz∗-κ2N,N)] (pz∗ = pz, dmpz; pzH = pyrazole; dmpzH = 3,5-dimethylpyrazole) with wet AgBF4 in a 1:1 ratio lead to the cationic pyrazolylamidino complexes fac-[Mn(OH2)(CO)3(NHC(CH3)pz∗-κ2N,N)]BF4. The aquo ligand is readily substituted by 2,6-xylylisocyanide (CNXyl) to give fac-[Mn(CNXyl)(CO)3(NHC(CH3)pz∗-κ2N,N)]BF4. The pyrazole complexes fac-[Mn(pz∗H)(CO)3(NHC(CH3)pz∗-κ2N,N)]BF4 are obtained by treating fac-[MnBr(CO)3(NCMe)2] with AgBF4 and then with pyrazole (pzH or dmpzH), in a 1:1:2 ratio. A similar reaction using 1:1:1 ratio and AgClO4 leads to the acetonitrile complexes fac-[Mn(NCMe)(CO)3(NHC(CH3)pz∗-κ2N,N)]ClO4. The X-ray structures of the complexes show moderate hydrogen bonds interactions between the N-bond hydrogen of the pyrazolylamidino ligand and the anion. In the aquo complex, one of the hydrogens of the coordinated water molecule is also involved in a hydrogen bond.

Graphical abstractThe X-ray structures of manganese tricarbonyl cationic pyrazolylamidino complexes show moderate hydrogen bonds interactions between the anion (BF4− or ClO4−) and the N-bond hydrogen of the pyrazolylamidino ligand and, in one case, one of the hydrogens of an aquo ligand.Figure optionsDownload full-size imageDownload as PowerPoint slide