Organomonophosphines in Pt(II) Coordination Complexes. Part I. Monomeric Square Planar (PtP₄, PtP₃X and PtP₂X₂)

GRAPHICAL ABSTRACT

Abstract

Organomonophosphines are very useful as soft P-donor ligands in the chemistry of platinum. In this review are summarized and analyzed one hundred and eighty Pt(II) coordination complexes in which P-donor ligands are only monodentate. There are Pt(II) atoms in a distorted square planar environment with the inner coordination spheres: PtP₄, PtP₃X (X = H, F, O, N, Cl, S, Br or I), and PtP₂×₂ (X = H, F, O, N, CN, or B). These complexes crystallize in four crystal systems: tetragonal (1.2%) < orthorhombic (16.6%) < triclinic (35%) < monoclinic (47.2%). In PtP₂X₂ derivatives the cis-configuration by far prevails. Of the organomonophosphines, PPh₃ is by far the most common ligand. The mean values of Pt-P bond distances elongated in the sequence: 2.236 Å (trans to O) < 2.24 Å (trans to F) < 2.245 Å (trans to N) < 2.248 Å (trans to Cl) < 2.252 Å (trans to Br) < 2.257 Å (trans to I) < 2.312 Å (trans to P) < 2.338 Å (trans to H). This order reflects the trans-effects of the respective atom. The chelating -O,O′-, -N,N′-, and -B,B′- donor ligands create a wide variability of three-, four-, five-, and six-membered metallacycles. There are at least two types of isomerism: cis- and trans- as well as distortion, which latter is more common.

Keywords:

• Structure
• Pt(II)
• organomonophosphines
• trans-effect
• isomers