Cyclometallaphosphazene Complexes of Titanium(IV)

Abstract

Cyclometallacyclophosphazene complexes of titanium(IV) corresponding to [{N(PPh₂NR)₂}_nTiCl_4‐n], [{N(PPh₂NR)₂}_nTiCl_2‐n (OPrⁱ)₂], and [{N(PPh₂NR)₂}_n (OPrⁱ)_2‐n](R=Ph or SiMe₃, G=CH₂CH₂, n=1 or 2) have been synthesized under anhydrous and inert conditions by the reaction of acyclic bis‐silylated phosphazene ligand (A), [HN(PPh₂NSiMe₃)₂], or bis‐phenylated phosphazene ligand (B), [HN(PPh₂NPh)₂] with TiCl₄, TiCl₂(OPrⁱ)₂ or (OPrⁱ)₂ in 1∶1 and 2∶1 molar ratios. These titanatriazadiphosphorines were characterized by elemental analyses (C, H, N, Cl and Ti), molecular weight determination, and spectral studies including IR and NMR (¹H, ¹³C, and ³¹P), which have indicated monomeric nature of the complexes and bidentate mode of bonding by phosphazene moiety leading to a trigonal bipyramidal and octahedral geometries around the titanium atom in 5 and 6 coordination numbers.

Keywords:

• metallatriazadiphosphorines
• heterometallacyclophosphazenes
• cyclotitanaphosphazenes
• bis‐silylated and bis‐phenylated phosphazenes

Acknowledgments

Dedicated to Professor Dr. Herbert W. Roesky on his 70th birthday.

We gratefully acknowledge financial support from the Department of Science and Technology, New Delhi. The authors are thankful to the Regional Research Laboratory, Jammu and Central Drug Research Institute, Lucknow for spectral studies. Yash Paul is thankful to Department of Science and Technology, New Delhi for Junior Research Fellowship.