Phenanthroline based pincer complexes useful as catalysts for the preparation of methanol from carbondioxide

Patent metadata

Field	Value
Publication number	US-10449529-B2
Application number	US-201615549827-A
Country	US
Kind code	B2
Filing date	Feb 10, 2016
Priority date	Feb 10, 2015
Publication date	Oct 22, 2019
Grant date	Oct 22, 2019

Abstract

The present invention relates to a novel phenonthroline based pincer complexes and process for preparation thereof. The present invention also provides a one pot process for the conversion of carbon dioxide to methanol in the presence of a molecularly defined pincer-type single-site Ru-catalyst and secondary amine. Further the present invention provides the use of phenonthroline based pincer complexes for the esterification of alcohols and hydrogenation of esters under mild conditions.

First claim

The invention claimed is:

1. A phenanthroline pincer complex, wherein said complex is selected from HCl(CO)Ru(Phen-(tBu)PNN) (3), H(CO)Ru-(Phen-(tBu)PNN (4) and H(CO)Ru(η1BH4)(Phen-(tBu)PNN) (5).

2. The phenanthroline pincer complex as claimed in claim 1 , wherein said complex is used as a catalyst for hydrogenation of lactones to diols and esters to alcohols.

3. The phenanthroline pincer complex as claimed in claim 2 , wherein said catalyst is used for dehydrogenation of diols to lactones, alcohol to esters and secondary alcohols to ketones.

4. A process for the preparation of a phenanthroline pincer complex comprising the steps of:
a) adding solution of Lithium diisopropylamide and tBuOK in suitable solvent to a solution of 2-methyl-1,10-phenanthroline (1) in ether at a temperature in a range of 0° to 5° C. followed by stirring the reaction mixture for a period in a range of 30 to 40 minutes to obtain a solution;

b) adding a solution of di-tert-butylchlorophosphine in ether to the solution as obtained in step (a) and stirring for a period of 1 to 2 hours at a temperature in a range of −50° C. to −78° C. followed by stirring at temperature in a range of 25° C. to 30° C. for the period in a range of 12 to 14 hours to obtain Phen-PNN-(tBu) ( 2 );

c) mixing the Phen-PNN(tBu) (2) as obtained in step (b), RuHC1(CO)(PPh 3 ) 3 and tetrahydrofuran heating at a temperature in a range of 60° C. to 70° C. for the period in a range of 5 to 6 hours under argon atmosphere to obtain HC1(CO)Ru(Phen-(tBu)PNN) (3);

d) adding Sodium bis(trimethylsilyl)amide to the compound of step (c) in C 6 H 6 to obtain H(CO)Ru-(Phen-(tBu)PNN) (4);

e) stirring the reaction mixture comprising HC1(CO)Ru(Phen-(tBu)PNN) (3) and NaBH 4 in toluene and ethanol at a temperature in a range of 50° C. to 70° C. for a period in a range of 10 to 15 minutes followed by stirring at a temperature in a range of 25° C. to 30° C. for a period in a range of 4 to 6 hours to obtain H(CO)Ru(η1BH4)(Phen-(tBu)PNN) (5).

5. The process as claimed in claim 4 , wherein the solvent used in step (a) is selected from hexane, heptane, tetrahydrofuran (THF), diethyl ether, toluene, and etheylbenzene.

Assignees

• Council Scient Ind Res
• Council Scient Ind Res

Inventors

• Balaraman Ekambaram
• Landge Vinod Gokulkrishna
• Midya Siba Prasad
• Sahoo Manoj Kumar
• Jaiswal Garima

Classifications

• B01J31/20

  Carbonyls · CPC title

• B01J31/183

  with more than one complexing nitrogen atom, e.g. phenanthroline · CPC title

• B01J31/1815

  with more than one complexing nitrogen atom, e.g. bipyridyl, 2-aminopyridine · CPC title

• B01J31/2404

  Cyclic ligands, including e.g. non-condensed polycyclic ligands, the phosphine-P atom being a ring member or a substituent on the ring · CPC title

• B01J31/2447

  and phosphine-P atoms as substituents on a ring of the condensed system or on a further attached ring · CPC title