Crystal structure of bis-[(R,R)-1,2-(bi-naph-thyl-phospho-nito)ethane]-dichlorido-iron(II) di-chloro-methane disolvate.

Benjamin E Rennie,Robert H Morris,Alan J Lough

doi:10.1107/s2056989020011160

Abstract

In the title compound (systematic name: bis-{1,2-bis[12,14-dioxa-13-phospha-penta-cyclo-[13.8.0.02,11.03,8.018,23]tricosa-1(15),2(11),3(8),4,6,9,16,18(23),19,21-deca-en-13-yl]ethane}-dichlorido-iron(II) di-chloro-methane disolvate), [FeCl2(C42H28O4P2)2]·2CH2Cl2, the FeII ion lies on a crystallographic twofold rotation axis and is coordinated by four P atoms from two (R,R)-1,2-bis-(bi-naphthyl-phospho-n-ito)ethane (BPE) ligands and two Cl ligands in a distorted cis-FeCl2P4 octa-hedral coordination geometry. In the crystal, weak C-H⋯O and C-H⋯π inter-actions link the mol-ecules into layers lying parallel to (001). A weak intra-molecular C-H⋯O hydrogen bond is also observed. The asymmetric unit contains one CH2Cl2 solvent mol-ecule, which is disordered over two sets of site with refined occupancies in the ratio 0.700 (6):0.300 (6).

Highlights

As an extension of these studies, we describe the synthesis and crystal structure of the iron(II) complex FeCl2(BPE)2, which crystallized as a dichloromethane solvate
The FeII ion lies on a crystallographic twofold rotation axis and is coordinated by four P atoms from two BPE ligands and two Cl ligands in a distorted cis-FeCl2P4 octahedral coordination geometry
The P atoms are bonded to two O atoms, one C atom and coordinated to the FeII ion in distorted tetrahedral geometries

Summary

Chemical context

The ligand (R,R)- or (S,S)-1,2-bis(binaphthylphosphonito)ethane (C42H28O4P2; BPE) prepared from either (R)- or (S)1,10-bi(2-naphthol) (C20H14O2; BINOL) has been used extensively in asymmetric catalysis, as has the related ligand (R) or (S)-2,20-bis(diphenylphosphino)-1,10-binaphthyl (C44H32P2; BINAP). The BINAP ligand has been coordinated to ruthenium and used for the asymmetric hydrogenation of ketones (Doucet et al, 1998), among many other examples. The BINAP ligand has been coordinated to iron (Vogler, 2016) to make the complex [FeCl2(BINAP)2]. The BPE ligand and similar bidentate and monodentate phosphonite ligands have been coordinated to rhodium and iridium and used for asymmetric alkene and quinoline hydrogenation reactions, respectively (Claver et al, 2000; Norman et al, 2008; Reetz & Li, 2006), and to ruthenium for asymmetric transfer hydrogenation (Guo et al, 2005a,b). As an extension of these studies, we describe the synthesis and crystal structure of the iron(II) complex FeCl2(BPE), which crystallized as a dichloromethane solvate

Structural commentary

Supramolecular features

Database survey

Synthesis and crystallization

Refinement