Magnesium and Titanium Complexes of Polyanionic Phosphazenate Ligands

Abstract

Polyanionic phosphazenates constitute polydentate ligands that offer several chelating sites, facilitating the accommodation of multinuclear metal arrays. Here, we describe their coordination behavior in the presence of magnesium and titanium. Reaction of the hexaprotic cyclotriphosphazene (iBuNH)6P3N3 (1) with nBu2Mg in thf in 1:2 ratio yields the dinuclear magnesium complex [(thf)Mg(iBuN)2(iBuNH)4P3N3]2 (2), while a 1:4 ratio gives the octanuclear complex [(thf)3(nBuMg)2Mg2(iBuN)6P3N3]2 (3). Both magnesium complexes exist as dimers in the solid state. In addition to metal ligand interactions, dimer 2 is supported by four hydrogen bonds (N−H···N interactions). The reaction of (CyNH)6P3N3 (4) with two equivalents of (Me2N)4Ti produces the dinuclear complex {(Me2N)2Ti}2(CyN)4(CyNH)2P3N3 (5), in which the phosphazenate ligand accommodates the two titanium atoms in tridentate coordination sites. The metalation reactions were followed by 31P NMR. Metal complexes 2, 3, and 5 were characterized by X-ray structure analysis.

Ansa versus spiro selectivity in substitution reactions of a mono ansa fluorodioxycyclotriphosphazene derivative with diols

“…118.03 (11) 115.82 (11) 118.6(4) 119.0(4) 118.5(4) 118.6(4) P1-N1-P2 119.52 (12) 118.43 (12) 118.0 (5) (17) 1.588 (6) 1.599 (6) 1.598 (6) 1.585(6) P2-O2…”

“…The determination of substitution patterns is very important for cyclophosphazene chemistry due to the fact that the multiple available pathways in these nucleophilic substitution reactions lead to a large number of cyclophosphazene derivatives [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Systematic studies of the substitution patterns will lead to a fundamental understanding of the factors which control these processes.…”

Alkaline and alkaline earth metals

“…123 Reaction of the hexaprotic cyclotriphosphazene ( i BuNH) 6 P 3 N 3 with n-Bu 2 Mg in yielded the magnesium complex [(THF)Mg( i BuN) 2 (BuNH) 3 ] 2 , while a 1 : 4 ratio provided the octanuclear complex [(THF) 3 (n-BuMg) 2 Mg 2 (( i BuN) 6 P 3 N 3 ] 2 . 124 The phospha-Grignard reagent Mg(P(SiMe 3 ) 2 X(THF) [X = Br/Me] has been synthesised and structurally characterised as the phosphide-bridged dimer. 125…”

Magnesium(II) Complexes with High Emission: The Distinct Charge‐Transfer Process from Transition Metal

“…Besides, comparing to other alkali and alkaline‐earth metals, Mg exhibited better coordination stability . Therefore, according to the distinct luminescence property from transition metals and better coordination stability,, there is a great chance to achieve Mg coordinated fluorescence materials through coordination chemistry , . However, the mechanism why magnesium exhibited better fluorescent activity than first‐row transition‐metals is not fully investigated because achieving crystal structures of Mg II complexes still remains a challenge.…”