Neptunium(V) N,N′-dicyanoguanidinate complexes with electroneutral N-donor ligands

Abstract Four new Np(V) dicyanoguanidinate complexes with neutral N-donor ligands were synthesized and structurally characterized: [(NpO 2 )(Bipy)(C(NH 2 )(NCN) 2 )(H 2 O)]·2H 2 O ( 1 ), [(NpO 2 )(Phen)(C(NH 2 )(NCN) 2 )(H 2 O)]·2H 2 O ( 2 ), [(NpO 2 )(TPTZ)(C(NH 2 )(NCN) 2 )]·3H 2 O ( 3 ) and [(NpO 2 )( i Pr-BTP)(C(NH 2 )(NCN) 2 )(H 2 O)] ( 4 ). Dicyanoguanidinate anions appear as a result of a transformation of the dicyanamide during the synthesis. The coordination environment of Np atoms in compounds is pentagonal bipyramids with “yl” oxygen atoms in apical positions. The equatorial plane of the bipyramid in 1 and 2 complexes is formed by: two nitrogen atoms from two anions [C(NH 2 )(NCN) 2 ] − , two nitrogen atoms from neutral ligands Bipy ( 1 ) and Phen ( 2 ), and an oxygen atom of a water molecule. The equatorial plane of bipyramid 3 is formed by five nitrogen atoms: two atoms from two [C(NH 2 )(NCN) 2 ] − anions and three atoms from TPTZ. The equatorial plane of bipyramid 4 is formed by one nitrogen atom of the anion, three nitrogen atoms of the i Pr-BTP ligand, and an oxygen atom of the water molecule. In compounds 1 – 3 , the anion acts as a bidentate-bridging ligand; in compound 4 , the anion is a monodentate ligand.