The preparation and crystal structure of η²-nitrato(η⁴-hexadecamethylcyclooctaphosphazene (N¹,N²,N⁴,N⁵))cobalt(II) nitrate

Abstract

cobalt(I1) nitrate. Crystals of 2 are triclinic, a = 10.891(2), b = 11.201(2),c = 14.944(2)A,a = 93.21(1), P = 95.66(1), y = 104.69(1)",Z= 2, spacegroupP1. Thecrystalstructure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.037 and R, = 0.047 for 5165 reflections with 1 2 3o(Z). All the hydrogen atoms were found. The structure consists of a cation [N,P,Me,, CoN03]+ and a free nitrate anion. The cobalt atom is coordinated by an unsymmetrical bidentate nitrate ion and by four nitrogen atoms of the phosphazene ring. The metal is attached near one end of the ring, forming six-, ten-, and two four-membered chelate rings, and induces bond length variations which are independent of local conformation and which arise from the localization of bonding electrons.

Silicon Analogues of Crown Ethers and Cryptands: A New Chapter in Host–Guest Chemistry?

“…The largest structurally characterized example is the twenty‐four‐membered ring (Me 2 PN) 12 21. To date the known complexes of these multidentate N‐donor ligands are limited to late transition metals, for example, the neutral complexes [{(Me 2 PN) 6 }MCl 2 ] (M=Pt, Pd)22 and the ionic complex [{(Me 2 PN) 8 }Co(NO 3 )][NO 3 ]23 in which the cyclophosphazene behaves as a bi‐ or tetradentate ligand, respectively. The endocyclic coordination chemistry of cyclophosphazenes deserves to be revisited in the light of recent findings 11.…”

Siliciumanaloga von Kronenethern und Cryptanden: ein neues Kapitel in der Wirt‐Gast‐Chemie?

“…Das größte strukturell charakterisierte Beispiel ist der 24‐gliedrige Ring (Me 2 PN) 12 21. Bislang sind für diese mehrzähnigen Stickstoffdonor‐Liganden nur Komplexe mit späten Übergangsmetallen bekannt, beispielsweise die Neutralkomplexe [{(Me 2 PN) 6 }MCl 2 ] (M=Pt, Pd)22 und der ionische Komplex [{(Me 2 PN) 8 }Co(NO 3 )][NO 3 ],23 in denen die Cyclophosphazene als zwei‐ bzw. vierzähnige Liganden fungieren.…”