Cycloaddition reactions of tetraaza macrocycle supported group 4 imido complexes and reversible addition of aryl isocyanate to a coordinated ureate ligand

Abstract

The first tetraaza macrocycle supported zirconium imido complex [Zr(tmtaa)(NC₆H₃Prⁱ₂-2,6(py)] and the new titanium imido base-free analogues [Ti(tmtaa)(NAr)](Ar = Ph or C₆H₄Me-4) react with isocyanates to give N,N′-bound ureate complexes; these can undergo exchange reactions with excess aryl isocyanate via reversible insertion into the Ti-N(ureate) bond; the X-ray structure of [Zr(tmtaa)-{(NC₂H₃Prⁱ₂-2,6)(CO)(NBu^t)}] is described {H₂tmtaa = tetramethyldibenzotetraaza[14]annulene).