Ligand variations in [ReX(diimine)(CO)3] complexes : Effects on photocatalytic CO2 reduction

Two series of complexes [MX(diimine)(CO)3] (M = Tc, Re) have been prepared, fully characterised and investigated for their ability to act as photocatalysts for the reduction of CO2 to CO. One series consists of complexes with different aromatic diimine ligands while keeping X = Br– constant. The second series describes complexes with diimine = 2,2-bipyridine and variations in the anionic ligand X–. Although numerous complexes of this type have been prepared and investigated before, a systematic study of their photocatalytic activity has not yet been carried out. Electrochemical and spectroscopic characterisation of these complexes has been performed with the objective of better understanding their respective activity in the photocatalytic CO2 reduction.Despite various modifications, catalytic activity is retainedfor all compounds exhibiting fluorescence, including [99TcCl(bipy)(CO)3], whereas nonfluorescing compounds did not convert CO2 to CO. The correlation of catalytic activity and spectroscopic or electrochemical properties such as absorption or emission wavelengths, redox potentials or Stern–Volmer constants for the reductive quenching of the excited complexes is difficult. Nevertheless, the study emphasises the possibility to obtain [ReX(CO)3(diimine)] complexes with a wide range of physicochemical properties by ligand variations and the great potential of compounds of this class of complexes as inorganic photosensitisers. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

[1]  B. Brunschwig,et al.  Involvement of a binuclear species with the Re-C(O)O-Re moiety in CO2 reduction catalyzed by tricarbonyl rhenium(I) complexes with diimine ligands: strikingly slow formation of the Re-Re and Re-C(O)O-Re species from Re(dmb)(CO)3S (dmb = 4,4'-dimethyl-2,2'-bipyridine, S = solvent). , 2003, Journal of the American Chemical Society.

[2]  L. A. Summers,et al.  Derivatives of 1,10-Phenanthroline-5,6-quinone , 1970 .

[3]  Vincenzo Balzani,et al.  Luminescent and Redox-Active Polynuclear Transition Metal Complexes. , 1996, Chemical reviews.

[4]  J. Sanz-Aparicio,et al.  Metallic Carbonyl Complexes Containing Heterocycle Nitrogen Ligands. 2. Tricarbonylbromo(3,3'-R-2,2'-biquinoline)Rhenium(I) Compounds , 1994 .

[5]  G. Ferraudi,et al.  A mechanistic investigation of the photoinduced reduction of carbon dioxide mediated by tricarbonylbromo(2,2'-bipyridine)rhenium(I) , 1985 .

[6]  G. Calzaferri,et al.  Photoreduction and electroreduction of carbon dioxide by a novel rhenium(I) p-phenyl-terpyridine carbonyl complex , 1992 .

[7]  M. Wrighton,et al.  Ground and excited state electron transfer processes involving fac-tricarbonylchloro(1,10-phenanthroline)rhenium(I). Electrogenerated chemiluminescence and electron transfer quenching of the lowest excited state , 1978 .

[8]  W. Kaim,et al.  Proof of innocence for the quintessential noninnocent ligand TCNQ in its tetranuclear complex with four [fac-Re(CO)3(bpy)]+ groups: unusually different reactivity of the TCNX ligands (TCNX = TCNE, TCNQ, TCNB). , 2003, Inorganic chemistry.

[9]  C. Duboc,et al.  Mechanism and product characterization from the electroreduction of heterodinuclear complexes [(C5Me5)ClM(μ-L)Re(CO)3X](PF6), M=Rh or Ir, L=2,2′-azobispyridine or 2,2′-azobis(5-chloropyrimidine), X=halide , 2004 .

[10]  J. McGarvey,et al.  Complexes of functionalized dipyrido[3,2-a:2',3'-c]-phenazine: a synthetic, spectroscopic, structural, and density functional theory study. , 2005, Inorganic chemistry.

[11]  A. Spek,et al.  Synthesis and characterization of 9,10‐bis(arylimino)‐9,10‐dihydrophenanthrenes, the structure of (Z,Z)‐9,10‐bis(phenylimino)‐9,10‐dihydrophenanthrene and PdCl2‐[(E,E)‐9,10‐bis(phenylimino)‐9,10‐dihydrophenanthrene] in the solid state and in solution , 1996 .

[12]  J. Lehn,et al.  Efficient photochemical reduction of CO2 to CO by visible light irradiation of systems containing Re(bipy)(CO)3X or Ru(bipy)32+–Co2+ combinations as homogeneous catalysts , 1983 .

[13]  G. Sheldrick.  Phase annealing in SHELX-90: direct methods for larger structures , 1990 .

[14]  G. Kavarnos,et al.  Fundamentals of Photoinduced Electron Transfer , 1993 .

[15]  T. C. Bruice,et al.  Some electrochemical and chemical properties of methoxatin and analogous quinoquinones. , 1982, Proceedings of the National Academy of Sciences of the United States of America.

[16]  R. Scopelliti,et al.  Reactivity of the organometallic fac-[(CO)3ReI(H2O)3]+ aquaion. Kinetic and thermodynamic properties of H2O substitution. , 2003, Inorganic chemistry.

[17]  R. Schibli,et al.  Reactions with the technetium and rhenium carbonyl complexes (NEt4)2[MX3(CO)3]. Synthesis and structure of [Tc(CN-But)3(CO)3](NO3) and (NEt4)[Tc2(μ-SCH2CH2OH)3(CO)6] , 1996 .

[18]  D. J. Stufkens.  The Remarkable Properties of α-Diimine Rhenium Tricarbonyl Complexes in Their Metal-to-Ligand Charge-Transfer (MLCT) Excited States , 1992 .

[19]  A. I. Krasna.  PROFLAVIN CATALYZED PHOTOPRODUCTION OF HYDROGEN FROM ORGANIC COMPOUNDS , 1979 .

[20]  W. Kaim,et al.  Epr evidence for related electronic structures of α-diimine complexes with [Ru(bpy) 2 ] 2+ and re(CO) 3 (halide) fragments , 1987 .

[21]  M. Nazeeruddin,et al.  Luminescence and intramolecular energy-transfer processes in isomeric cyano-bridged rhenium(I)-rhenium(I) and rhenium(I)-ruthenium(II)-rhenium(I) polypyridyl complexes , 1992 .

[22]  Maria Cristina Burla,et al.  SIR97: a new tool for crystal structure determination and refinement , 1999 .

[23]  M. Grätzel.  Photoelectrochemical cells : Materials for clean energy , 2001 .

[24]  L. Wallace,et al.  Photophysical properties of rhenium(I) tricarbonyl complexes containing alkyl- and aryl-substituted phenanthrolines as ligands , 1993 .

[25]  F. Calderazzo,et al.  Reactions of halogeno carbonyls of rhenium (I) . , 1972 .

[26]  J. Lehn,et al.  Synthesis and photophysical and electrochemical properties of new halotricarbonyl(polypyridine)rhenium(I) complexes , 1988 .

[27]  G. Ferraudi,et al.  Further studies of the photoinduced reduction of carbon dioxide mediated by tricarbonylbromo(2,2'-bipyridine)rhenium(I) , 1987 .

[28]  O. Ishitani,et al.  Photocatalytic reduction of carbon dioxide using [fac-Re(bpy)(CO)3(4-Xpy)]+ (Xpy = pyridine derivatives) , 1999 .

[29]  G. Sheldrick,et al.  SHELXL: high-resolution refinement. , 1997, Methods in enzymology.

[30]  D. Morse,et al.  Nature of the lowest excited state in tricarbonylchloro-1,10-phenanthrolinerhenium(I) and related complexes , 1974 .

[31]  Raymond Ziessel,et al.  Photochemical and Electrochemical Reduction of Carbon Dioxide to Carbon Monoxide Mediated by (2,2′‐Bipyridine)tricarbonylchlororhenium(I) and Related Complexes as Homogeneous Catalysts , 1986 .

[32]  K. Kalyanasundaram.  Luminescence and redox reactions of the metal-to-ligand charge-transfer excited state of tricarbonylchloro-(polypyridyl)rhenium(I) complexes , 1986 .

[33]  Per Lincoln,et al.  DNA-BINDING OF DELTA- RU(PHEN)2DPPZ 2+ AND LAMBDA- RU(PHEN)2DPPZ 2+ , 1993 .

[34]  W. Hieber,et al.  Über Metallcarbonyle. XXXIX. Aminsubstituierte Rheniumcarbonyle , 1941 .

[35]  W. Kaim,et al.  Structures and spectroelectrochemistry (UV–vis, IR, EPR) of complexes [(OC)3ClRe]n(abpy), n=1, 2; abpy=2,2′-azobispyridine , 2000 .

[36]  Peng Wang,et al.  A high molar extinction coefficient sensitizer for stable dye-sensitized solar cells. , 2005, Journal of the American Chemical Society.

[37]  B. Twamley,et al.  fac-Tri­carbonyl­chloro(1,10-phenanthroline)­rhenium(I) , 2002 .

[38]  V. Gramlich,et al.  Synthesis and reactivity of [NEt4]2[ReBr3(CO)3]. Formation and structural characterization of the clusters [NEt4][Re3(µ3-OH)(µ-OH)3(CO)9] and [NEt4][Re2(µ-OH)3(CO)6] by alkaline titration , 1994 .

[39]  W. Kaim,et al.  Electronic structure of the "molecular light switch" bis(bipyridine)dipyrido[3,2-a:2',3'-c]phenazineruthenium(2+). Cyclic voltammetric, UV/visible and EPR/ENDOR study of multiply reduced complexes and ligands , 1993 .

[40]  S. Yanagida,et al.  Remarkable Solvent Effects on the Photocatalytic Behavior of [fac-Re(bpy)(CO)3Br] (bpy = 2,2′-bipyridine). Selective Hydrogen Evolution in Ether Solvents in the Presence of Triethylamine , 1989 .

[41]  A. Kirpal,et al.  Über einige Derivate und Oxydationsprodukte von 2-Amino-pyridin , 1927 .

[42]  W. Kaim.  Complexes with 2,2â²-azobispyridine and related 'S-frame' bridging ligands containing the azo function , 2001 .

[43]  J. Mccleverty.  Photochemistry of polypyridine and porphyrin complexes , 1993 .

[44]  Anthony L. Spek,et al.  Journal of , 1993 .

[45]  P. Matousek,et al.  Ligand-to-Diimine/Metal-to-Diimine Charge-Transfer Excited States of [Re(NCS)(CO)3(α-diimine)] (α-diimine = 2,2‘-bipyridine, di-iPr-N,N-1,4-diazabutadiene). A Spectroscopic and Computational Study , 2005 .

[46]  T. Meyer,et al.  Application of the energy gap law to nonradiative, excited-state decay , 1983 .