The present invention provides a method of forming an oxidatively-stable aqueous Eu(II) complex by synthesizing ligands that coordinate to large, soft, electron rich metals like Eu(II). The invention also provides an oxidatively stable aqueous Eu(II) complex. The complex can be used for a variety of purposes some of which include, but are not limited to, in paramagnetic chemical exchange saturation transfer, as a medical diagnostic, as a semiconductor, and for use in forming materials.