Neuartige basische Liganden für die homogenkatalytische Homologisierung von Methanol zu Ethanol, II [1]. Synthese und komplexchemisches Verhalten potentiell zwei- und dreizähniger P–N- und P–O-haltiger Chelatliganden / Novel Basic Ligands for the Homogeneous Catalytic Homologation of Methanol to Ethanol, II [1]. Synthesis and Complex Chemical Behaviour of Potential Bi- and Tridentate P–N and P–O Containing Chelate Ligands

Abstract

Tridentate P-N and P-O ligands of the type RP(XC5H4N)2 (1a, b, a′, b′) [X = O, NH: R = CH3 (a, a′), t-Bu (b, b′)] and PhP(CH2C4H7O)2 (1c″) are obtained by reaction of RPCl2 with 2-hydroxy- and 2-aminopyridine and Li2PPh with tetrahydrofurfuryil chloride, respectively. In a similar way the potential bidentate ligand Ph2PCH2C4H7O (2c″) is formed by the action of LiPPh2 on ClCH2C4H7O. Potential tridentate ligands as RP(C4H3O)2 (3a‴-c‴) [R = CH3 (a‴), t-Bu (b‴), Ph (c‴)| with two furyl-phosphorus bonds can be isolated from RPCl2 and furyllithium. The complex chemical behaviour towards Mo(CO)6 or carbonyl derivatives of chromium was elucidated for 2c‴ and 3a‴- c‴, resulting in the formation of (OC)5MoPPh2CH2C4H7O (4c″) and trans-(OC)4Cr[RP(C4H3O)2]2 (5a‴-c‴), respectively. In the case of 5a‴ an X-ray investigation proved 3a‴-c‴ to be only monodentate P-ligands 5a‴ crystallizes in the monoclinic space group P21/c with Z = 2. 1c″ is the most versatile species within this series and functions probably as a tri-, bi- and monodentate P-O ligand. With 1c″ and 3c″ some homologation experiments of methanol at 200 °C and 304 bar synthesis gas pressure were carried out