High-valent (MN)-N-VI (M = Ru, Os) species are important reagents in nitrogen transfer. reactions; the unique withdrawing properties of polyoxometalate (POMs) ligands would possibly modify the reactivity of the (MN)-N-VI functional group. In the present paper, density functional theory (DFT) and natural bond orbital (NBO) analysis have been employed to calculate electronic structures, M-VI-N bonding, and redox properties of high-valent metal nitrido derivatives of Keggin-type POMs, [PW11O39{(MN)-N-VI}](4-) (M = Ru, Os, Re). Our calculations show that [PW11O39{RuN}](4-) possesses stronger antibonding interaction between metal and nitrogen atoms compared with anions [PW11O39{OsN}](4-) and [PW11O39{ReN}](4-). A large increase in the Ru-N bond length of anion [PW11O39{RuN}](4-) in the excited states has been found; the effective order and composition of the molecular orbital in anion [PW11O39{RuN}](4-) is a key factor in determination of the increase of the Ru-N bond length in the excited states. The substitution effects of central tetrahedron heteroatoms (XO4, X = Al, Si, P, As) in anions [XW11O39{RuN}](4-) affect the relative energy of the LUMO; the relevant orbital energy increases in the order Al(III) < Si(IV) < P(V) approximate to As(V). The RuN unit is the reduced center. NBO analysis of the extent of the bonding interaction between the ruthenium and the nitrogen centers in [PW11O39{(RuN)-N-VI}](4-) shows that the Ru-N bond possesses a covalent feature and displays triple-, double-, and single-bond character when moving along the change of spin state ((1)1 -> (3)1 -> (5)1).