Study on Effect of Water in CO 2 Insertion into Ruthenium Hydride Complex

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1 , ACTA CHIMICA SINICA Vol 61, 2003 No 5, Ξ, a b Ξ ( a ) ( b ) THF H 2 O/ THF CO 2 TpRu(PPh 3 ) (CH 3 CN) H [ Tp = Hydrotris(pyrazolyl) borate ], CO 2 TpRu(PPh 3 ) (CH 3 CN) H 1 H, 31 P 13 C,, CO 2 Ru H TpRu(PPh 3 ) (CH 3 CN) ( 1 2OCHO) H 2 O, B3LYP,CO 2, CO 2 TpRu(PPh 3 ) (CH 3 CN) H Ru H TpRu (PPh 3 ) (CH 3 CN) ( 1 2OCHO) H 2 O TpRu(PPh 3 ) (H 2 O) ( 1 2OCHO), Study on Effect of Water in CO 2 Insertion into Ruthenium Hydride Complex YIN, Chuan2Qi Ξ, a WU, Shao2Wen b ( a Department of Pharmacy, Wuhan Institute of Chemical Technology, Wuhan ) ( b Department of Applied Biology & Chemical Technology, Hong Kong Polytechnic University, Hong Kong) Abstract A promoting effect of water on CO 2 insertion into TpRu ( PPh 3 ) (CH 3 CN) H [ Tp = Hydrotris (pyrazolyl) borate ] is observed In situ high2pressure 1 H, 31 P and 13 C NMR monitoring shows that CO 2 readily inserts into Ru H to form the hydrated metal formate TpRu ( PPh 3 ) ( CH 3 CN) ( 1 2OCHO) H 2 O in which the formate ligand is intermolecularly H2bonded to a water molecule Theoretical calculations carried out at the B3L YP level show that electrophilicity of the carbon center of CO 2 is enhanced by the formation of H2bonds between its oxygen atoms and H 2 O in the transition state of the process, and thus reaction barrier of the CO 2 insertion is significantly reduced in the presence of water The hydrated formate species TpRu ( PPh 3 ) (CH 3 CN) ( 1 2OCHO) H 2 O comes into equilibrium rapidly with another metal formate species TpRu ( PPh 3 ) ( H 2 O) ( 1 2OCHO), in which the coordinated H 2 O is intramolecularly H2bonded with the formate ligand Keywords formate ruthenium complex, electrophilicity, hydrogen2bonding, late transition state, energy barrier [2,3], [4] [5] [1],,, [4] Ξ E2mail : wh hb cn Received November 5, 2002 ; revised and accepted December 26, 2002 (No 2002AB068) Hong Kong Research Grant Council (No PolyU 32/ 96p)

2 No 5 : 667, TpRu ( PPh 3 ) (CH 3 CN) H (1) [6] 2 Tp 9, Ru H 2, 3H CH 3 CN, 1H, 13 C 1 H NMR, B3LYP, Hz,, Os(PPr 3) i 2 2(CO) ( 1 2OCHO) (CH CHPh) H 13 C NMR 1 J RuCl 3 3H 2 O Aldrich H C = Hz 1 [6b] [11] ( / ) : THF/ Na2benzophenone, /, / /,THF2d 8 / 13 C (99 99 %) 1 H, 31 P{ 1 H}, 13 C{ 1 H} 13 C NMR Bruker DPX 400, , MHz 1 H 13 C NMR, 31 P NMR 85 % CO 2 THF2d 8 19 h 13 C H 3 PO 4 (D 2 O ) 5 mm Wilmad { 1 H} NMR (a) 13 C NMR (b) ISSECC2CNR Figure 1 13 C{ 1 H} (a) and proton coupled 13 C (b) NMR spectra for CO 2 the reaction of 1 with 13 CO 2 (012 MPa) in anhydrous THF2d 8 at room g 1, 5 mm Wilmad temperature for 19 h 3, 012 ml THF2d 8, ( = 0110) THF2d 8 1, (PPh 3 ) (CH 3 CN) ( 1 2OCHO), Scheme Mpa 13 CO 2, 13 C{ 1 H} NMR H, 31 P 13 C 1 H 13 C NMR, 1 J H C = Hz 1 3, PH 3 PPh 3 Pentium PC Gaussian 98 [7] B3LYP 6231G 3 3 [8] LANL2DZ [9] Ru P [ ( d) = ] [10], STO23G Tp PH 3, 6231G STO23G CO 2 THF 1 13 CO 2 THF 19 h, 31 P2 2 1 H{ 13 C} NMR ( 8111) [11], 2 13 C{ 1 H} 1 H 13 C NMR 1, 13 C{ 1 H}NMR 2 TpRu2 TpRu(PPh 3 ) ( 2 2OCHO) Scheme CO 2 H 2 O/ THF 1 13 CO 2 H 2 O/ THF2d 8 ( = 0110 ) 10 min, 31 P{ 1 H} NMR { H} NMR 5419, ( 79181) 90 % 1

3 3, 4 P 1 H{ 13 C} NMR 3 Tp 9, , 3H CH 3 CN, 1H 13 C 1 H NMR 1 J C H = Hz, 31 P{ 1 H} NMR,, 5718,, min, H{ 13 C} C 1 H NMR Figure 2 13 C{ 1 H} (a) and proton coupled 13 C (b) NMR spectra for the 1 J C H = Hz, 4 reaction of 1 with 13 CO 2 (012 MPa) in H 2 O/ THF2 d 8 ( = 0110 H 2 O) 3 at room temperature for 20 min 1 3 TpRu ( PPh 3 ) (CH 3 CN) D 1, 3 31 P, 13 C 1 H NMR,, 2 D NMR Tp, PPh 3, CH 3 CN 3 3, 4 OC ( O) D TpRu (PPh 3 ) (CH 3 CN) D 1 THF2d 8 ( = 2 3, 0110) D 2 O 3 h 3, 4 13 C NMR 2, C{ 1 H} NMR (a) , (3 1) [9] 3, 4 13 C NMR, Ru H, 1 J H C = Hz Hz 668 Vol 61, CO 2 THF2d 8 ( = 0110) 20 NMR 2108 CH 3 CN, min 13 C{ 1 H} NMR (a) 13 C NMR (b) TpRu ( PPh 3 ) (CH 3 CN) ( 1 2OCHO), (DFT) B3LYP THF 1 Ru O C H, H 2 O/ THF 1 2 3, 3 4 CH 3 CN, 3, 4, 4 1, 4 TS CH 3 CN,4 TS kj / mol 3 TpRuH(PH 3 ) (CH 3 CN) (1) CO 2 (a) (b) (kj/ mol) Figure 3 Free energy (kj/ mol) profiles for the reactions of TpRuH(PH 3 ) (CH 3 CN) (1) with CO 2 (a) The absence of water and (b) in the presence of water

4 No 5 : [ :nm, : ( ) ] Table 1 Optimized parameters for the intermediates and transition states [ bond length : nm, bond angle : ( ) ] Parameter R(1) R(1 ) TS TS P(2) P(3) Parameter R(1) R(1 ) TS TS P(2) P(3) RuH RHH RO(1) Ru RHO(1) RCO(1) RHO(2) RCO(2) OCO RCH ( :10-1 nm) Figure 4 Optimized structures with selected geometry parameters (bond lengths are given in 10-1 nm),ts TS,Ru H C H nm( 4) TS TpRu(PPh 3 ) (CH 3 CN) ( 1 2OCHO) H 2 O, Ru H ( Ru H CO 2 ), Ru O 2, 4, 3 3, Scheme 2, CO 2, TpRu ( PPh 3 ) 2 (H 2 O) ( 1 2OCHO) 3,4,, 3 (b) 1 CO 2 TS (1 + CO 2 ) kj/ mol (13219 kj/, 3 3 mol) NMR 1 TS TS, TS Ru H Ru H 3, nm, TS ( nm), TS C H (DFT) B3LYP 3 ( nm) TS ( nm), TS, TS,,Ru O ( nm),,,

5 670 Vol 61, 2003 Scheme , 5 Jessop, P G ; Hsiao, Y ; Ikariya, T ; Noyori, R J Am! Chem Soc 1996, 118, (a) Chan, W C ; Lau, C P ; Jia, G Organometallics 1997, References 1 (a) Behr, A In Carbon Dioxide Activation by Metal Complexes, VCH, Weinheim, Germany, 1988 (b) Leitner, W Angew Chem, Int Ed Engl 1995, 34, 2207 (c) Leitner, W Coord Chem Rev 1996, 153, Whittlesey, M K ; Perutz, R N ; Moore, M H Organo2 metallics 1996, 15, (a) Musashi, Y ; Sakaki, S J Chem Soc, Dalton Trans 1998, 577 (b) Musashi, Y ; Sakaki, S J Am Chem Soc 2000, 122, Tsai, J 2C ; Nicholas, K M J Am Chem Soc 1992, 114, 16, 34 ( b) Chen, Y2Z ; Chan, W C ; Lau, C P ; Jia, G S Organometallics 1997, 16, 1241 ( c) Ng, S M ; Lau, C P ; Lin, Z Organometallics 1999, 18, Frisch, M J ; Trucks, G W ; Schlegel, H B ; Scuseria, G E Gaussian 98, Revision A 7, Gaussian Inc, Pittsburgh, PA, Miehlich, B ; Savin, A ; Preuss, H Chem Phys Lett 1989, 157, Hay, P J ; Wadt, W R J Chem Phys 1985, 82, Huzinaga, S Gaussian Basis Sets for Molecular Calculations, Elsevier Science Publisher Co, Amsterdam, Levy, G C ; Nelson, G L In Carbon213 Nuclear Magnetic Resonance for Organic Chemists, Wiley, New York, 1972 (A SHEN, H ; LU, Z S )

6 Vol 61, 2003 No 5, Graphical Abstract Steric Hindrance Effect of Hemicyanine Derivatives on Their Spectral Sensitization Efficiencies of Nanocrystalline TiO 2 Electrodes YAO, Qiao2Hong ; SHAN, Lu ; LI, Fu2You ; YIN, Dong2Dong ; HUANG, Chun2Hui Acta Chimica Sinica 2003, 61 (5), 647 Three novel hemicyanine derivatives with different length of alkyl chains between the adsorbing group ( RSO - 3 ) and the chromophore group, ( E) 2N2( 42sulfopropyl ) 242 [ 22( 42N, N2diethylaminophenyl ) ethenyl ] pyridinium ( EPS), ( E)2 N2( 42sulfobutyl )242[ 22( 42N, N2 diethylaminophenyl ) ethenyl ] pyridinium ( EPS4), and ( E) 2N2 (42sulfobutyl) 242[ 22( 42N, N2diethylaminophenyl ) ethenyl ] quinolinium ( EQS4 ) were synthesized and the steric hindrance effect of hemicyanine derivative dye molecules on their photosensitization efficiencies on nanocrystalline TiO 2 electrodes was studied Structure and Stability of ( BN) n Clusters J IA, Jian2Feng ; WU, Hai2Shun ; J IAO, Hai2Jun Acta Chimica Sinica 2003, 61 (5), 653 (BN) n ( n = 1 16) clusters were studied using quantum chemistry methods The geometries, binding energies and nucleus independent chemical shifts (NICS) of ring and cage structures were discussed The relationship between structure and stability was obtained Also the differences of HF, B3LYP and MP2 methods as to this problem were compared Effect of SO 2 on NO Catalytic Oxidation V Mechanism of SO 2 Promotion over NiO/ 2 Al 2 O 3 LI, Ping ; LU, Guan2Zhong Acta Chimica Sinica 2003, 61 (5), 660 A mechanism is proposed to explain the promotion of SO 2 in NO catalytic oxidation at low temperatures over NiO/ 2Al 2 O 3 Study on Effect of Water in CO 2 Insertion into Ruthenium Hydride Complex YIN, Chuan2Qi ; WU, Shao2Wen Acta Chimica Sinica 2003, 61 (5), 666 CO 2 insertions into TpRu(PPh 3 ) (CH 3 CN) H (1) in anhydrous THF and in H 2 O/ THF have been studied The results show that reaction barrier of the CO 2 insertion is significantly reduced in the presence of water CO 2 readily inserts into Ru H to form the hydrated metal formate TpRu ( PPh 3 ) ( CH 3 CN) ( 1 2OCHO) H 2 O ( 3) in which the formate ligand is intermolecularly H2bonded to a water molecule 3 comes into equilibrium rapidly with another metal formate species TpRu(PPh 3 ) (H 2 O) ( 1 2OCHO) (4), in which the coordinated H 2 O is intramolecularly H2bonded with the formate ligand