Preparation and structural characterization of 4-pyridylboron-capped iron(II) clathrochelates and their chemical transformations into hybrid metallo(IV)-phthalocyaninatoclathrochelate derivatives

Abstract

Mixed boron,antimony-capped iron(II) tris-dioximate monoclathrochelates and their hybrid phthalocyaninatoclathrochelate derivatives, the molecules of which are decorated with the single N-donor 4-pyridyl group, were obtained using two different approaches, such as ([Formula: see text] a transmetallation (a capping group exchange) reaction of their antimony-capped macrobicyclic precursors, and (ii) the direct template condensation of the Fe[Formula: see text] ion as a matrix. The obtained complexes were characterized using elemental analysis, 1H and [Formula: see text]C{1H} NMR, MALDI-TOF MS, and UV–vis spectra, and by the single-crystal X-ray diffraction experiments. Solution UV-vis spectra of 4-pyridyl-terminated iron(II) phthalocyaninatoclathrochelates can be described as a superposition of the spectrum of its metallocomplex precursor M[Formula: see text]Pc and that of the iron(II)-encapsulating semiclathrochelate fragment. As follows from the X-ray diffraction data for the hybrid hafnium(IV)-capped tris-dimethylglyoximate pthalocyaninatoclathrochelate and its macrobicyclic boron,antimony-capped precursor, their FeN6-coordination polyhedra possess the geometry close to intermediate between a trigonal prism (TP) and a trigonal antiprism with the distortion angles [Formula: see text] of 20–30[Formula: see text]. Due to a non-equivalence of their capping fragments, it can be also described as a distorted truncated trigonal pyramid. ZrN[Formula: see text]-coordination polyhedron in the hybrid complex possesses the geometry of a capped TP. 4-Pyridylboron-capped pthalocyaninatoclathrochelates are proposed as prospective monodentate N-donor 3D-ligands for the design of various clathrochelate-based coordination assemblies, polytopic and polynuclear systems.