Supporting Information Jacques et al. 10.1073/pnas.0907775105 SI Text Crystal Structure Analysis. Crystallographic data are summarized in Table S2. Data collection was performed at 150 K with an Oxford-diffraction XCalibur S diffractometer with a CCD area detector with graphite monochromated Mo-K radiation ( 0.71073 Å). Empirical absorption correction (Abspack) was performed. Molecular structures were solved by direct methods and refined on F 2 by full-matrix least-squares techniques with the SHELXTL package with anisotropic thermal parameters. All nonhydrogen atoms were refined anisotropically; hydrogen atoms were found by Fourier synthesis and refined with individual isotropic displacement parameters. X-ray suitable crystals of the complexes [Ni(DO)(DOH)pn]- (ClO 4 ) and [Co(DO)(DOH)pnBr 2 ] were grown by vapor diffusion of diethyl ether into a filtered concentrated solution of each complex in acetone. Crystals of [Co(MO)(MOH)pnCl 2 ] were grown by vapor diffusion of diethyl ether into a filtered concentrated solution in DMSO. The atomic coordinates have been deposited in the Cambridge Structural Database, Cambridge Crystallographic Data Centre (CSD reference nos. 738486 for compound [Co(MO)(MO- H)pnCl 2 ], 738487 for [Ni(DO)(DOH)pn] (ClO 4 ), and 738485 for [Co(DO)(DOH)pnBr 2 ]). Evaluation of Thermodynamic Equilibrium Constants for Homolytic and Heterolytic Hydrogen Evolution. The equilibrium constants for homolytic and heterolytic H 2 evolution from p-cyanoanilium tetrafluoroborate in CH 3 CN can be determined using the methodology developed by Kellett and Spiro (1), based on the known values of standard potentials of the following couples: p- cyanoanilinium tetrafluoroborate/h 2 (E 0.59 V vs. Ag/ AgCl), Co II /Co I and Co III /Co II for the different complexes. Both pathways are considered as the sum of one reaction and one or two redox half-equations. Heterolytic route: 1/2 Co I AH 1/2 Co III 1/2H 2 A [1] 1/2 Co III e 1/2 Co II 1/2 Co II e 1/2 Co I Net reaction: AH e 1/2H 2 A Thus, r G 1 1/2 E Co III /Co II 1/2 E Co II /Co I E H /H 2 Homolytic route: Co I AH CoI II 1/2H 2 A [2] Co II e Co I Net reaction: AH e 1/2H 2 A Thus, r G E Co II /Co I E H /H 2 Table S1 contains the calculated values for the thermodynamic equilibrium constants for homolytic and heterolytic hydrogen evolution catalyzed by [Co(DO) 2 BF 2 pnbr 2 ], [Co(DO)(DOH)pnBr 2 ], and [Co(dmgBF 2 ) 2 (CH 3 CN) 2 ]. 1. Kellett RM, Spiro TG (1985) Cobalt(I) porphyrin catalysis of hydrogen-production from water. Inorg Chem 24:2373 2377. 1of14
Fig. S1. X-ray structure of [Co(DO)(DOH)pnBr 2 ] (50% thermal ellipsoids). 2of14
Fig. S2. X-ray structure of the cation in [Ni(DO)(DOH)pn] (ClO 4 ) (50% thermal ellipsoids). 3of14
Fig. S3. Cyclic voltammograms of [Co((DO) 2 BF 2 )pnbr 2 ] (1 mm) in CH 3 CN solution containing 0.1 M [ n Bu 4 N][BF 4 ] in presence of tosic acid monohydrate (0, 1, 3, 5, 10 equiv.) recorded at a glassy carbon electrode (scan rate 100 mv s 1 ). 4of14
Fig. S4. Cyclic voltammograms of [Co((DO) 2 BF 2 )pnbr 2 ] (1 mm) in CH 3 CN solution containing 0.1 M [ n Bu 4 N][BF 4 ] in presence of anilinium tetrafluoroborate (0, 1, 3, 5, 10 equiv) recorded at a glassy carbon electrode (scan rate 100 mv s 1 ). 5of14
Fig. S5. Cyclic voltammograms of [Co((DO) 2 BF 2 )pnbr 2 ] (1 mm) in CH 3 CN solution containing 0.1 M [ n Bu 4 N][BF 4 ] in presence of trifluoroacetic acid (0, 3, 5, 10 equiv) recorded at a glassy carbon electrode (scan rate 100 mv s 1 ). 6of14
Fig. S6. Cyclic voltammograms of [Co(DO)(DOH)pnBr 2 ] (1 mm) in CH 3 CN solution containing 0.1 M [ n Bu 4 N] [BF 4 ] in presence of tosic acid monohydrate (0, 1, 3, 5, 10 equiv) recorded at a glassy carbon electrode (scan rate 100 mv s 1 ). 7of14
Fig. S7. Cyclic voltammograms of [Co(DO)(DOH)pnBr 2 ] (1 mm) in CH 3 CN solution containing 0.1 M [ n Bu 4 N][BF 4 ] in presence of trifluoroacetic acid (0, 1, 3, 5, 10 equiv) recorded at a glassy carbon electrode (scan rate 100 mv s 1 ). 8of14
Fig. S8. Cyclic voltammograms of [Ni(DO)(DOH)pn](ClO 4 ) (1 mm) in CH 3 CN solution containing 0.1 M [ n Bu 4 N][BF 4 ] in presence of triethylammonium hydrochloride (0, 3, 5, 10 equiv) recorded at a glassy carbon electrode (scan rate 100 mv s 1 ). 9of14
Fig. S9. Cyclic voltammograms of [Ni(DO)(DOH)pn] (ClO 4 ) (1 mm) in CH 3 CN solution containing 0.1 M [ n Bu 4 N][BF 4 ] in presence of anilinium tetrafluoroborate (0, 1, 3, 10 equiv) recorded at a glassy carbon electrode (scan rate 100 mv s 1 ). 10 of 14
Fig. S10. Cyclic voltammograms of [Ni(DO) 2 (BF 2 )pn](cio 4 ) (1 mm) in CH 3 CN solution containing 0.1 M [ n Bu 4 N][BF 4 ] in presence of tosic acid monohydrate (0, 1, 3, 10 equiv) recorded at a glassy carbon electrode (scan rate 100 mv s 1 ). 11 of 14
Fig. S11. Cyclic voltammograms of [Ni(MO)(MOH)pnCl] (1 mm) in CH 3 CN solution containing 0.1 M [ n Bu 4 N][BF 4 ] in presence of p-cyanoanilinium tetrafluoroborate (0, 3, 5, 10 equiv) recorded at a glassy carbon electrode (scan rate 100 mv s 1 ). 12 of 14
Table S1. Calculated values for the thermodynamic equilibrium constants for homolytic and heterolytic hydrogen evolution catalyzed by [Co(DO)(DOH)pnBr 2 ], [Co((DO) 2 BF 2 )pnbr 2 ], and [Co(dmgBF 2 ) 2 (CH 3 CN) 2 ] E 1/2 (M III /M II ) E 1/2 (M II /M I ) r G (1) r G (2) heterolytic, kj mol 1 homolytic, kj mol 1 [Co(DO)(DOH)pnBr 2 ] 0.57 1.11 24 50 [Co((DO) 2 BF 2 )pnbr 2 ] 0.38 0.84 2 24 [Co(dmgBF 2 ) 2 (CH 3 CN) 2 ] 0.2 (irrev. cathodic) 0.93 2.5 33 13 of 14
Table S2. Crystal data and structural refinement details for complexes Co(MO)(MOH)pnCl 2, Ni(DO)(DOH)pn (ClO 4 ), and Co(DO)(DOH)pnBr 2 Compound Co(MO)(MOH)pnCl 2 Ni(DO)(DOH)pn (ClO 4 ) Co(DO)(DOH)pnBr 2 Formula C 9 H 15 Cl 2 CoN 4 O 2 C 11 H 19 ClN 4 NiO 6 C 11 H 19 Br 2 CoN 4 O 2 Molecular mass, Da 341.08 397.46 458.05 Color Green Yellow Green Crystal size 0.50 0.08 0.06 mm 0.5 0.17 0.05 mm 0.5 0.3 0.3 mm Crystal system Monoclinic Monoclinic Monoclinic Space group Pbca P2 1 /c P2 1 /n a, Å 13.6410(4) 7.09950(10) 14.6065(4) b, Å 13.0684(4) 16.5930(3) 13.8864(3) c, Å 14.9927(6) 13.5935(2) 15.8819(3), 90 90 90, 90 102.1435(17) 95.926(2), 90 90 90 V, Å 3 2672.69(16) 1565.51(4) 3204.14(13) Z 8 4 8 calcd, mg m 3 1.695 1.686 1.899,cm 1 16.83 14.46 60.65 Reflections collected 9,562 15,877 18,811 Unique reflections (R int ) 3,073 (R int 0.0327) 3,757 (R int 0.0336) 7,259 (R int 0.0257) Observed reflections I 2 (I) 1,789 2,869 4,374 Refined parameters 223 284 513 R indices, all data R1 0.0659, wr2 0.0447 R1 0.0399, wr2 0.0633 R1 0.0721, wr2 0.0988 Final R indices, observed reflections R1 0.0263, wr2 0.0414 R1 0.0269, wr2 0.0615 R1 0.0423, wr2 0.0941 Goodness of fit S 0.766 1.028 0.842 (max/min), e Å 3 0.339 and 0.257 0.352 and 0.343 0.839 and 0.475 R1 F o F c / F o. wr2 { w(f o 2 F c 2 ) 2 / w(f o 2 ) 2 } 1/2. w 1/ 2 (F o 2 ) (ap) 2 bp, where P 2F c 2 Max(F o 2,0) /3 (see CIF for a and b values). 14 of 14