Molybdenum(0) Fischer ethoxycarbene complexes: Synthesis, X-ray crystal structures and DFT study

Molybdenum(0) Fischer ethoxycarbene complexes: Synthesis, X-ray crystal structures and DFT study Armand Jansen van Rensburg, a Marilé Landman, a * Petrus H. van Rooyen, a Marrigje M. Conradie b and Jeanet Conradie b * Supporting information Table of Contents Optimized Cartesian coordinates (Å)... 2 1. [(CO) 5 MoC(OEt)(C 4 H 3 S)] (1)... 2 2. [(CO) 5 MoC(OEt)(C 4 H 3 O)] (2)... 2 3. [(CO) 5 MoC(OEt)(C 4 H 3 NMe)] (3)... 3 4. [(CO) 5 MoC(OEt)(C 8 H 5 S 2 )] (4)... 4 5. [(PPh 3 )(CO) 4 MoC(OEt)(C 4 H 3 S)] (5)... 4 6. [(PPh 3 )(CO) 4 MoC(OEt)(C 4 H 3 O)] (6)... 6 7. [(PPh 3 )(CO) 4 MoC(OEt)(C 4 H 3 NMe)] (7)... 7 8. [(PPh 3 )(CO) 4 MoC(OEt)(C 8 H 5 S 2 ) (8)... 8 9. [(AsPh 3 )(CO) 4 MoC(OEt)(C 4 H 3 S)] (9)... 10 10. [(AsPh 3 )(CO) 4 MoC(OEt)(C 4 H 3 O)] (10)... 11 11. [(AsPh 3 )(CO) 4 MoC(OEt)(C 4 H 3 NMe)] (11)... 12 12. [(AsPh 3 )(CO) 4 MoC(OEt)(C 8 H 5 S 2 )] (12)... 14 Crystallographic supplementary material... 15 Complex 3: Crystal data and structure refinement... 15 Complex 4: Crystal data and structure refinement... 16 Complex 5: Crystal data and structure refinement... 18 Complex 7: Crystal data and structure refinement... 19 Complex 8: Crystal data and structure refinement... 20 Complex 9: Crystal data and structure refinement... 21 Complex 10: Crystal data and structure refinement... 22 Complex 12: Crystal data and structure refinement... 23 Figures S 1 6 (Perspective drawings of 4b, 4c, 4d, 5b, 9b and 10b... 24 S1

Optimized Cartesian coordinates (Å) All compounds were optimized B3LYP as implemented in the Gaussian 09 program package. Geometries of the neutral complexes were optimized in gas phase with the triple-ζ basis set 6-311G(d,p) on all atoms except Mo and As, where def2- TZVPP was used. The coordinates of the lowest energy conformation of each complex are provided. 1. [(CO) 5 MoC(OEt)(C 4 H 3 S)] (1) Mo -0.239711000-1.202778000 0.000000000 C -1.595514000-0.735396000 1.481003000 C -1.595514000-0.735396000-1.481003000 C 1.076183000-1.805933000-1.465084000 C 1.076183000-1.805933000 1.465084000 O -2.357510000-0.513853000 2.306712000 O -2.357510000-0.513853000-2.306712000 O 1.775310000-2.206250000-2.281537000 O 1.775310000-2.206250000 2.281537000 C -0.983296000-3.102032000 0.000000000 O -1.408707000-4.167809000 0.000000000 C 0.487283000 0.927356000 0.000000000 C -0.368479000 2.101272000 0.000000000 O 1.738334000 1.372068000 0.000000000 S 0.330362000 3.725696000 0.000000000 C -1.230386000 4.443507000 0.000000000 H -1.325560000 5.519456000 0.000000000 C -2.239886000 3.513516000 0.000000000 H -3.290601000 3.768984000 0.000000000 C -1.751162000 2.190978000 0.000000000 H -2.394847000 1.325833000 0.000000000 C 2.904682000 0.513721000 0.000000000 H 2.869220000-0.116834000 0.887775000 H 2.869220000-0.116834000-0.887775000 C 4.123953000 1.413285000 0.000000000 H 5.027879000 0.799218000 0.000000000 H 4.140329000 2.049799000 0.886899000 H 4.140329000 2.049799000-0.886899000 2. [(CO) 5 MoC(OEt)(C 4 H 3 O)] (2) Mo 0.942909000 0.326536000 0.000000000 C 1.181308000-1.117328000 1.462460000 C 1.181308000-1.117328000-1.462460000 C 0.829532000 1.769456000-1.459910000 C 0.829532000 1.769456000 1.459910000 S2

O 1.353662000-1.906545000 2.272303000 O 1.353662000-1.906545000-2.272303000 O 0.829532000 2.577489000-2.275026000 O 0.829532000 2.577489000 2.275026000 C 2.970889000 0.588838000 0.000000000 O 4.109600000 0.729784000 0.000000000 C -1.246389000-0.081104000 0.000000000 C -1.815457000-1.413102000 0.000000000 O -2.282463000 0.750714000 0.000000000 O -0.966032000-2.494225000 0.000000000 C -1.723310000-3.605796000 0.000000000 H -1.187129000-4.540481000 0.000000000 C -3.053886000-3.291276000 0.000000000 H -3.876312000-3.988466000 0.000000000 C -3.115641000-1.876984000 0.000000000 H -3.995412000-1.255389000 0.000000000 C -2.127208000 2.189566000 0.000000000 H -1.563261000 2.476980000 0.887377000 H -1.563261000 2.476980000-0.887377000 C -3.517591000 2.791736000 0.000000000 H -3.443118000 3.881923000 0.000000000 H -4.076071000 2.485934000 0.887187000 H -4.076071000 2.485934000-0.887187000 3. [(CO) 5 MoC(OEt)(C 4 H 3 NMe)] (3) Mo -1.217026000-0.164201000-0.002596000 C -0.885251000-1.578717000-1.466632000 C -0.929977000-1.536742000 1.510137000 C -1.712875000 1.218505000 1.434066000 C -1.644467000 1.181827000-1.495578000 O -0.753425000-2.366442000-2.287784000 O -0.815793000-2.300668000 2.356094000 O -2.066418000 1.962405000 2.234493000 O -1.951324000 1.907230000-2.331304000 C -3.176303000-0.693267000-0.034081000 O -4.283564000-1.000031000-0.052480000 C 1.013977000 0.332764000 0.021190000 C 2.069510000-0.646093000 0.015337000 O 1.563710000 1.548810000 0.029632000 N 3.459955000-0.395778000-0.010824000 C 4.173760000 0.878182000-0.062871000 H 3.961666000 1.480106000 0.819067000 H 5.240778000 0.658703000-0.101679000 H 3.891727000 1.445568000-0.948156000 C 4.114765000-1.580387000 0.003478000 H 5.193676000-1.607479000-0.016640000 C 3.202409000-2.625677000 0.041775000 H 3.441986000-3.676476000 0.062484000 C 1.935186000-2.045721000 0.047258000 H 0.999056000-2.572527000 0.076030000 S3

C 0.790775000 2.771352000 0.050261000 H 0.131979000 2.784838000-0.816852000 H 0.185267000 2.783894000 0.955756000 C 1.764667000 3.933010000 0.022216000 H 1.206593000 4.872339000 0.041126000 H 2.372630000 3.918230000-0.885056000 H 2.427509000 3.915034000 0.890147000 4. [(CO) 5 MoC(OEt)(C 8 H 5 S 2 )] (4) Mo -0.427095000-2.489891000 0.000000000 C -1.659395000-1.750694000 1.477510000 C -1.659395000-1.750694000-1.477510000 C 0.735568000-3.349483000-1.466803000 C 0.735568000-3.349483000 1.466803000 O -2.362389000-1.374415000 2.299914000 O -2.362389000-1.374415000-2.299914000 O 1.336159000-3.884089000-2.285048000 O 1.336159000-3.884089000 2.285048000 C -1.543475000-4.193555000 0.000000000 O -2.178178000-5.150195000 0.000000000 C 0.735441000-0.552797000 0.000000000 C 0.148128000 0.765994000 0.000000000 O 2.056479000-0.383332000 0.000000000 S 1.174681000 2.210268000 0.000000000 C -0.209417000 3.264984000 0.000000000 C -1.388490000 2.533519000 0.000000000 H -2.368701000 2.991308000 0.000000000 C -1.185501000 1.148125000 0.000000000 H -1.995859000 0.436730000 0.000000000 C 3.009240000-1.471743000 0.000000000 H 2.839743000-2.080737000 0.887436000 H 2.839743000-2.080737000-0.887436000 C 4.394646000-0.857723000 0.000000000 H 5.144440000-1.652733000 0.000000000 H 4.548455000-0.239935000 0.887018000 H 4.548455000-0.239935000-0.887018000 C -0.057801000 4.700984000 0.000000000 S -1.457271000 5.759450000 0.000000000 C -0.454720000 7.166881000 0.000000000 C 0.874483000 6.847056000 0.000000000 H 1.663983000 7.586232000 0.000000000 C 1.101076000 5.448129000 0.000000000 H 2.086871000 5.001903000 0.000000000 H -0.910138000 8.145130000 0.000000000 5. [(PPh 3 )(CO) 4 MoC(OEt)(C 4 H 3 S)] (5) Mo 0.611383000-1.282313000-0.850806000 S4

C 0.907151000-0.118971000-2.516188000 O 1.058517000 0.435707000-3.510967000 C 1.921011000-2.569750000-1.630053000 O 2.651650000-3.337881000-2.086388000 C 0.241116000-2.628404000 0.637723000 O -0.013278000-3.457025000 1.398469000 C -0.807275000-2.227403000-1.958094000 O -1.560200000-2.786498000-2.624965000 C 2.328653000-0.263520000 0.140310000 O 3.235893000-0.790654000 0.972284000 C 3.161389000-2.133447000 1.500364000 H 3.029779000-2.831944000 0.675088000 H 2.293769000-2.195638000 2.158596000 C 4.450954000-2.392302000 2.254128000 H 4.428964000-3.399402000 2.678085000 H 4.579140000-1.677687000 3.069963000 H 5.312894000-2.318258000 1.587967000 C 2.795769000 1.088145000-0.141213000 C 2.136834000 2.142241000-0.747362000 H 1.122161000 2.068728000-1.105236000 C 2.902320000 3.326638000-0.829193000 H 2.543666000 4.245001000-1.273620000 C 4.153388000 3.180936000-0.287039000 H 4.939629000 3.919641000-0.233291000 S 4.414776000 1.605591000 0.352200000 P -1.319024000 0.217982000 0.181092000 C -1.246533000 0.576208000 2.002201000 C -2.405279000 0.776373000 2.764988000 H -3.380865000 0.698199000 2.301643000 C -2.314876000 1.066281000 4.124216000 H -3.220669000 1.213056000 4.701911000 C -1.068896000 1.163446000 4.740475000 H -1.001063000 1.386674000 5.799329000 C 0.087941000 0.965998000 3.991021000 H 1.061953000 1.035653000 4.462156000 C -0.001171000 0.669361000 2.632610000 H 0.900728000 0.505967000 2.057716000 C -3.024703000-0.502245000 0.019698000 C -4.107484000 0.214271000-0.501433000 H -3.973695000 1.232543000-0.842206000 C -5.370020000-0.372491000-0.587728000 H -6.196198000 0.196355000-0.999590000 C -5.569526000-1.676669000-0.146905000 H -6.550799000-2.132408000-0.215717000 C -4.498517000-2.395412000 0.381683000 H -4.641929000-3.413003000 0.726800000 C -3.236337000-1.816318000 0.460165000 H -2.418389000-2.393777000 0.871433000 C -1.517622000 1.903895000-0.568088000 C -1.650202000 2.001832000-1.961575000 H -1.662037000 1.104685000-2.569156000 S5

C -1.767281000 3.243647000-2.577744000 H -1.871078000 3.299118000-3.655357000 C -1.740450000 4.409960000-1.813305000 H -1.824987000 5.377956000-2.294207000 C -1.601728000 4.323711000-0.431278000 H -1.577530000 5.225099000 0.170960000 C -1.494429000 3.079324000 0.190165000 H -1.388434000 3.030192000 1.266224000 6. [(PPh 3 )(CO) 4 MoC(OEt)(C 4 H 3 O)] (6) Mo 0.982579000-1.109476000-0.845460000 C 1.094517000 0.107797000-2.503992000 O 1.154813000 0.682346000-3.495858000 C 2.503973000-2.165385000-1.587046000 O 3.364987000-2.804081000-2.015937000 C 0.812403000-2.503380000 0.632475000 O 0.683032000-3.364093000 1.389506000 C -0.236548000-2.267823000-1.996706000 O -0.866671000-2.935422000-2.689999000 C 2.431859000 0.201565000 0.180466000 O 3.409475000-0.104009000 1.044829000 C 3.610879000-1.441141000 1.550472000 H 3.669055000-2.133536000 0.711131000 H 2.752906000-1.709438000 2.168725000 C 4.894784000-1.427436000 2.356680000 H 5.080395000-2.423147000 2.767122000 H 4.829088000-0.720318000 3.186684000 H 5.744964000-1.150436000 1.729721000 C 2.589786000 1.625796000-0.059569000 C 3.517788000 2.551972000 0.371897000 H 4.359835000 2.335869000 1.007754000 C 3.147741000 3.802355000-0.182930000 H 3.646148000 4.751134000-0.063356000 C 2.017758000 3.566038000-0.914618000 H 1.373279000 4.195367000-1.505410000 O 1.669511000 2.267662000-0.850787000 P -1.162892000 0.071268000 0.176290000 C -1.209301000 0.287718000 2.022010000 C -2.408538000 0.222621000 2.744252000 H -3.340464000 0.018710000 2.232219000 C -2.415181000 0.409449000 4.124601000 H -3.351454000 0.349244000 4.668265000 C -1.227224000 0.668393000 4.804335000 H -1.234011000 0.810390000 5.879215000 C -0.030166000 0.736085000 4.096033000 H 0.900700000 0.932606000 4.616176000 C -0.020792000 0.541366000 2.716494000 H 0.916838000 0.582374000 2.178135000 C -2.748365000-0.852664000-0.118527000 S6

C -3.904084000-0.245606000-0.622016000 H -3.903986000 0.808596000-0.866309000 C -5.068333000-0.989211000-0.815479000 H -5.952331000-0.503151000-1.213216000 C -5.097424000-2.343688000-0.499611000 H -6.002353000-2.920876000-0.652317000 C -3.953786000-2.955240000 0.011302000 H -3.963611000-4.010631000 0.258717000 C -2.788481000-2.218652000 0.195309000 H -1.909397000-2.714661000 0.587366000 C -1.563582000 1.771562000-0.448154000 C -1.644019000 1.971936000-1.833160000 H -1.486821000 1.142281000-2.511604000 C -1.924144000 3.231491000-2.353125000 H -1.988300000 3.365268000-3.427136000 C -2.113762000 4.316744000-1.497221000 H -2.329347000 5.299214000-1.902318000 C -2.025995000 4.129640000-0.120855000 H -2.171358000 4.966641000 0.553162000 C -1.756719000 2.864701000 0.402191000 H -1.696153000 2.736230000 1.475163000 7. [(PPh 3 )(CO) 4 MoC(OEt)(C 4 H 3 NMe)] (7) Mo 0.633875000-1.136378000-0.949104000 C 0.909242000 0.171631000-2.510599000 O 1.039383000 0.799026000-3.464404000 C 2.049399000-2.279013000-1.760356000 O 2.857112000-2.961305000-2.226512000 C 0.255185000-2.627007000 0.385737000 O -0.007919000-3.538702000 1.043519000 C -0.675026000-2.050830000-2.191350000 O -1.362920000-2.591750000-2.941267000 C 2.331099000-0.136112000 0.150138000 O 3.199622000-0.707174000 1.000535000 C 3.011146000-2.035941000 1.533586000 H 2.951020000-2.744317000 0.707517000 H 2.070107000-2.056400000 2.084104000 C 4.188379000-2.338649000 2.440275000 H 4.064661000-3.333258000 2.875915000 H 4.253576000-1.614666000 3.255963000 H 5.128873000-2.326243000 1.884930000 C 2.828202000 1.192569000-0.139053000 C 2.085289000 2.295586000-0.582100000 H 1.034630000 2.275589000-0.812000000 C 2.923051000 3.415535000-0.623249000 H 2.657264000 4.419267000-0.913480000 C 4.179569000 2.986332000-0.227111000 H 5.110070000 3.530010000-0.165786000 S7

N 4.134982000 1.664601000 0.082274000 P -1.362803000 0.189225000 0.177673000 C -1.298609000 0.322724000 2.030835000 C -2.427815000 0.147047000 2.839693000 H -3.386732000-0.082680000 2.393259000 C -2.329570000 0.257275000 4.226114000 H -3.212722000 0.109898000 4.837774000 C -1.107458000 0.553373000 4.823068000 H -1.033328000 0.637719000 5.901512000 C 0.021176000 0.735792000 4.026045000 H 0.978144000 0.966757000 4.480805000 C -0.071845000 0.613312000 2.642311000 H 0.812982000 0.744570000 2.032320000 C -3.053921000-0.528930000-0.098768000 C -4.168892000 0.264836000-0.394468000 H -4.063259000 1.337679000-0.489926000 C -5.424384000-0.314403000-0.572690000 H -6.274976000 0.315702000-0.807999000 C -5.586440000-1.691228000-0.449705000 H -6.562852000-2.140800000-0.591081000 C -4.484563000-2.488908000-0.148327000 H -4.597462000-3.562938000-0.054352000 C -3.228500000-1.914186000 0.020724000 H -2.384887000-2.552061000 0.247820000 C -1.604798000 1.951220000-0.353305000 C -1.685849000 2.223947000-1.726806000 H -1.613957000 1.416000000-2.445132000 C -1.856722000 3.527425000-2.182018000 H -1.918150000 3.718881000-3.247256000 C -1.937634000 4.581860000-1.272735000 H -2.063233000 5.598555000-1.627765000 C -1.853559000 4.321803000 0.091818000 H -1.914733000 5.135455000 0.806040000 C -1.692388000 3.014578000 0.551244000 H -1.632754000 2.827865000 1.615747000 C 5.330751000 0.904970000 0.437398000 H 5.320661000 0.621010000 1.488821000 H 5.402924000 0.002094000-0.167078000 H 6.199226000 1.533205000 0.237664000 8. [(PPh 3 )(CO) 4 MoC(OEt)(C 8 H 5 S 2 ) (8) Mo 1.143103000 1.534366000-0.899954000 C 0.245979000 0.688722000-2.538986000 O -0.186565000 0.284885000-3.524396000 C 0.748722000 3.314646000-1.708897000 O 0.554043000 4.350197000-2.179931000 C 2.222182000 2.482458000 0.550909000 O 2.911691000 3.044832000 1.284400000 S8

C 2.828727000 1.516230000-2.032089000 O 3.752832000 1.553610000-2.717475000 C -0.845078000 1.656073000 0.111955000 O -1.296293000 2.616777000 0.932882000 C -0.476328000 3.689430000 1.443997000 H 0.008563000 4.195585000 0.609861000 H 0.289562000 3.257567000 2.089454000 C -1.387967000 4.625984000 2.212228000 H -0.799556000 5.448402000 2.626764000 H -1.881278000 4.105547000 3.035989000 H -2.154203000 5.046868000 1.557969000 C -1.982567000 0.788244000-0.132734000 C -2.041124000-0.449321000-0.751531000 H -1.172097000-0.936699000-1.163233000 C -3.324053000-1.018227000-0.784191000 H -3.540834000-1.970161000-1.250298000 C -4.293131000-0.228359000-0.189266000 S -3.595420000 1.232767000 0.451708000 P 1.916366000-0.754456000 0.195926000 C 1.710858000-0.926575000 2.034673000 C 2.627603000-1.634815000 2.822467000 H 3.500921000-2.084695000 2.367468000 C 2.431413000-1.759325000 4.196156000 H 3.154171000-2.304996000 4.792495000 C 1.316258000-1.185071000 4.801721000 H 1.166537000-1.281811000 5.871207000 C 0.397761000-0.481013000 4.026675000 H -0.472747000-0.028658000 4.488333000 C 0.597408000-0.347138000 2.654655000 H -0.115628000 0.210406000 2.061779000 C 3.718542000-1.152661000-0.015576000 C 4.174368000-2.414269000-0.415068000 H 3.468191000-3.205397000-0.630716000 C 5.539929000-2.667096000-0.541274000 H 5.874301000-3.648544000-0.858768000 C 6.467772000-1.668782000-0.260960000 H 7.529076000-1.865965000-0.361529000 C 6.023979000-0.412293000 0.146884000 H 6.737395000 0.373983000 0.365712000 C 4.661919000-0.154409000 0.263994000 H 4.338505000 0.829938000 0.576693000 C 1.091490000-2.282952000-0.458336000 C 1.113484000-2.512020000-1.842532000 H 1.627658000-1.819786000-2.498941000 C 0.480749000-3.624733000-2.387568000 H 0.510445000-3.786309000-3.459095000 C -0.195041000-4.521582000-1.559972000 H -0.693517000-5.385288000-1.985357000 C -0.227023000-4.299944000-0.186519000 H -0.751022000-4.990794000 0.464535000 C 0.415070000-3.190180000 0.363634000 S9

H 0.382988000-3.034194000 1.434195000 C -5.709640000-0.493954000-0.070645000 C -6.733729000 0.384758000 0.206074000 H -6.569467000 1.442787000 0.361934000 C -8.013850000-0.226555000 0.235343000 H -8.933307000 0.309320000 0.429002000 C -7.966160000-1.568170000-0.018671000 H -8.781333000-2.273875000-0.060694000 S -6.346825000-2.113690000-0.291003000 9. [(AsPh 3 )(CO) 4 MoC(OEt)(C 4 H 3 S)] (9) Mo 0.828029000-1.382603000-0.798469000 C 1.064577000-0.332272000-2.545957000 O 1.180838000 0.163418000-3.575947000 C 2.218939000-2.646513000-1.452330000 O 3.003730000-3.402116000-1.834014000 C 0.501754000-2.614380000 0.797588000 O 0.271213000-3.382316000 1.625745000 C -0.525012000-2.489679000-1.833315000 O -1.244649000-3.139003000-2.453933000 C 2.449410000-0.172412000 0.141268000 O 3.375473000-0.569819000 1.018560000 C 3.388075000-1.872860000 1.643837000 H 3.277601000-2.636058000 0.875068000 H 2.538370000-1.928479000 2.325573000 C 4.704578000-2.005132000 2.383317000 H 4.744530000-2.975705000 2.884154000 H 4.811210000-1.223326000 3.138339000 H 5.547637000-1.939760000 1.692527000 C 2.810309000 1.194588000-0.217887000 C 2.089996000 2.144702000-0.919349000 H 1.102155000 1.960186000-1.310610000 C 2.752639000 3.384768000-1.053601000 H 2.334753000 4.236629000-1.572407000 C 3.987029000 3.386584000-0.456331000 H 4.703159000 4.194548000-0.423127000 S 4.356191000 1.885207000 0.297505000 As -1.232483000 0.141044000 0.136244000 C -1.170237000 0.728282000 2.022069000 C -2.301013000 0.708511000 2.843944000 H -3.251464000 0.361308000 2.457967000 C -2.211726000 1.127930000 4.170869000 H -3.094098000 1.102956000 4.800772000 C -0.997404000 1.574445000 4.686119000 H -0.930631000 1.899922000 5.718200000 C 0.132782000 1.595830000 3.871364000 H 1.082753000 1.939592000 4.265287000 C 0.048901000 1.168660000 2.547729000 H 0.935486000 1.181309000 1.925777000 S10

C -3.018766000-0.700413000 0.078372000 C -4.160548000 0.008211000-0.307074000 H -4.085236000 1.048343000-0.598974000 C -5.405557000-0.619891000-0.323102000 H -6.283347000-0.061366000-0.628934000 C -5.521543000-1.956526000 0.049488000 H -6.489676000-2.444292000 0.033913000 C -4.387219000-2.666391000 0.437443000 H -4.467574000-3.708608000 0.724845000 C -3.141244000-2.043922000 0.448418000 H -2.269916000-2.613782000 0.746462000 C -1.612344000 1.841833000-0.793491000 C -1.727860000 1.816852000-2.188628000 H -1.626701000 0.882263000-2.728808000 C -1.975823000 2.990317000-2.896442000 H -2.065192000 2.956953000-3.976378000 C -2.100770000 4.202328000-2.218485000 H -2.288716000 5.116769000-2.769809000 C -1.982176000 4.233614000-0.831391000 H -2.078786000 5.172881000-0.298004000 C -1.741205000 3.058350000-0.118743000 H -1.654744000 3.095476000 0.960251000 10. [(AsPh 3 )(CO) 4 MoC(OEt)(C 4 H 3 O)] (10) Mo 1.232296000-1.128945000-0.790064000 C 1.263381000-0.015007000-2.522262000 O 1.285439000 0.514316000-3.540388000 C 2.831469000-2.113602000-1.445938000 O 3.739049000-2.714289000-1.832742000 C 1.149892000-2.407881000 0.798501000 O 1.073889000-3.205264000 1.627724000 C 0.114001000-2.465369000-1.846635000 O -0.465120000-3.233014000-2.477964000 C 2.529105000 0.380401000 0.170270000 O 3.532525000 0.225932000 1.042190000 C 3.892222000-1.060656000 1.591618000 H 4.052079000-1.762455000 0.773754000 H 3.063253000-1.417588000 2.204095000 C 5.149464000-0.863058000 2.414975000 H 5.450658000-1.816141000 2.856897000 H 4.981304000-0.147793000 3.223288000 H 5.969773000-0.499222000 1.792590000 C 2.510543000 1.802731000-0.123030000 C 3.323905000 2.851093000 0.256469000 H 4.195220000 2.763665000 0.883695000 C 2.794878000 4.024599000-0.336376000 H 3.174560000 5.031040000-0.260577000 C 1.691094000 3.624581000-1.036372000 H 0.963043000 4.147198000-1.634366000 S11

O 1.506710000 2.296446000-0.919811000 As -1.077489000-0.008228000 0.128258000 C -1.203286000 0.396362000 2.059727000 C -2.412881000 0.299248000 2.755350000 H -3.312937000-0.016066000 2.241632000 C -2.467194000 0.597641000 4.115784000 H -3.409523000 0.514193000 4.645932000 C -1.316891000 0.996783000 4.793131000 H -1.360726000 1.225689000 5.852046000 C -0.109294000 1.093876000 4.105971000 H 0.791177000 1.399338000 4.627268000 C -0.051623000 0.790607000 2.746624000 H 0.894881000 0.855855000 2.224314000 C -2.693742000-1.124328000-0.088214000 C -3.889345000-0.623383000-0.609678000 H -3.960225000 0.413011000-0.915513000 C -5.001181000-1.455641000-0.743217000 H -5.922193000-1.056898000-1.154163000 C -4.929943000-2.789523000-0.351964000 H -5.794262000-3.435385000-0.458125000 C -3.740735000-3.293058000 0.172313000 H -3.675003000-4.331860000 0.475497000 C -2.627016000-2.467355000 0.299158000 H -1.707796000-2.877451000 0.701032000 C -1.697002000 1.691578000-0.664154000 C -1.727553000 1.800297000-2.058697000 H -1.430609000 0.962903000-2.679015000 C -2.134014000 2.986567000-2.665010000 H -2.157164000 3.055551000-3.746870000 C -2.503501000 4.081096000-1.883435000 H -2.817773000 5.005520000-2.355131000 C -2.468884000 3.979995000-0.494931000 H -2.755055000 4.826315000 0.119976000 C -2.069613000 2.789673000 0.114154000 H -2.049409000 2.725154000 1.195063000 11. [(AsPh 3 )(CO) 4 MoC(OEt)(C 4 H 3 NMe)] (11) Mo 0.838713000-1.262488000-0.888077000 C 1.067512000-0.091699000-2.562235000 O 1.170164000 0.455757000-3.567099000 C 2.300758000-2.416905000-1.579215000 O 3.140025000-3.106312000-1.973872000 C 0.496554000-2.641126000 0.572636000 O 0.255371000-3.499599000 1.305830000 C -0.445598000-2.328200000-2.031047000 O -1.131706000-2.951575000-2.715454000 C 2.452960000-0.071196000 0.149569000 O 3.330518000-0.513427000 1.063146000 C 3.220768000-1.810863000 1.687933000 S12

H 3.216511000-2.578112000 0.914090000 H 2.275799000-1.850635000 2.230219000 C 4.402021000-1.970765000 2.625406000 H 4.337375000-2.938525000 3.128892000 H 4.407371000-1.189174000 3.388748000 H 5.347594000-1.934514000 2.079867000 C 2.859103000 1.266324000-0.225284000 C 2.061680000 2.261351000-0.808903000 H 1.033807000 2.134142000-1.098636000 C 2.808651000 3.439396000-0.906734000 H 2.482898000 4.387846000-1.302453000 C 4.067423000 3.153743000-0.402205000 H 4.945291000 3.778384000-0.336353000 N 4.108586000 1.865351000 0.024183000 As -1.264701000 0.132145000 0.129914000 C -1.223636000 0.572859000 2.056856000 C -2.371774000 0.533101000 2.853699000 H -3.324763000 0.250094000 2.423820000 C -2.297015000 0.848663000 4.209847000 H -3.193050000 0.808657000 4.819420000 C -1.079072000 1.210751000 4.780418000 H -1.023389000 1.455328000 5.835300000 C 0.068202000 1.252064000 3.990877000 H 1.020532000 1.531331000 4.428121000 C -0.002154000 0.928779000 2.637053000 H 0.896177000 0.951510000 2.032184000 C -3.034928000-0.738502000 0.005086000 C -4.188385000-0.031030000-0.345964000 H -4.132566000 1.026521000-0.572456000 C -5.420192000-0.681964000-0.411423000 H -6.307066000-0.123337000-0.689824000 C -5.511330000-2.040972000-0.122741000 H -6.469087000-2.546325000-0.176191000 C -4.365011000-2.750331000 0.229509000 H -4.425577000-3.809927000 0.450808000 C -3.132154000-2.104952000 0.288866000 H -2.251424000-2.675032000 0.556883000 C -1.682942000 1.893720000-0.660733000 C -1.776747000 1.985174000-2.054726000 H -1.635648000 1.104576000-2.671372000 C -2.051945000 3.207124000-2.663489000 H -2.123753000 3.264227000-3.743767000 C -2.225719000 4.351937000-1.886845000 H -2.434525000 5.304204000-2.361366000 C -2.126984000 4.267958000-0.500490000 H -2.259089000 5.154971000 0.109331000 C -1.858989000 3.043790000 0.112744000 H -1.786738000 2.991186000 1.192110000 C 5.335231000 1.249807000 0.523950000 H 5.266701000 1.043661000 1.591088000 H 5.536090000 0.316134000 0.000777000 S13

H 6.156901000 1.942080000 0.338643000 12. [(AsPh 3 )(CO) 4 MoC(OEt)(C 8 H 5 S 2 )] (12) Mo 1.061517000 1.718699000-0.883044000 C 0.199050000 0.972763000-2.589063000 O -0.214467000 0.620854000-3.602112000 C 0.725163000 3.541477000-1.605939000 O 0.561077000 4.603680000-2.027468000 C 2.116344000 2.567351000 0.645810000 O 2.795554000 3.074924000 1.426990000 C 2.791946000 1.708626000-1.944874000 O 3.751218000 1.744020000-2.579972000 C -0.942965000 1.782779000 0.108629000 O -1.413494000 2.698366000 0.965329000 C -0.618094000 3.772822000 1.512507000 H -0.148772000 4.319327000 0.695200000 H 0.159208000 3.336798000 2.140872000 C -1.550687000 4.658508000 2.315083000 H -0.981921000 5.480703000 2.756561000 H -2.027299000 4.097218000 3.121614000 H -2.329677000 5.082272000 1.677970000 C -2.056736000 0.892946000-0.165143000 C -2.088496000-0.306949000-0.856314000 H -1.214400000-0.738805000-1.316573000 C -3.351476000-0.917717000-0.896057000 H -3.546229000-1.847605000-1.413515000 C -4.332526000-0.199484000-0.233362000 S -3.670464000 1.246560000 0.476355000 As 1.763875000-0.704379000 0.154597000 C 1.432246000-1.028347000 2.075325000 C 2.332637000-1.744842000 2.869709000 H 3.246538000-2.136704000 2.440288000 C 2.065060000-1.951169000 4.222338000 H 2.773034000-2.503423000 4.830422000 C 0.896985000-1.448956000 4.791286000 H 0.691627000-1.609652000 5.843718000 C -0.003704000-0.734729000 4.004111000 H -0.914251000-0.338869000 4.439894000 C 0.264981000-0.519885000 2.653571000 H -0.437031000 0.044687000 2.052244000 C 3.687443000-1.142324000 0.047647000 C 4.147612000-2.388099000-0.387486000 H 3.445559000-3.157720000-0.683049000 C 5.516522000-2.649353000-0.448881000 H 5.861683000-3.617850000-0.793732000 C 6.434644000-1.673649000-0.070977000 H 7.498271000-1.877586000-0.121441000 C 5.980803000-0.431203000 0.367577000 H 6.688635000 0.336284000 0.659568000 S14

C 4.615306000-0.164182000 0.422335000 H 4.281637000 0.809813000 0.758841000 C 0.979042000-2.323794000-0.658746000 C 1.014283000-2.444027000-2.053319000 H 1.476610000-1.670702000-2.656648000 C 0.458081000-3.557285000-2.678981000 H 0.494450000-3.640030000-3.759362000 C -0.147952000-4.556244000-1.918018000 H -0.585031000-5.420716000-2.405005000 C -0.191116000-4.438481000-0.531099000 H -0.662276000-5.211353000 0.066133000 C 0.371630000-3.327993000 0.098901000 H 0.333718000-3.248842000 1.178399000 C -5.734727000-0.524516000-0.096465000 C -6.781256000 0.295470000 0.264359000 H -6.650768000 1.346482000 0.485908000 C -8.037142000-0.364067000 0.287231000 H -8.969248000 0.122999000 0.540131000 C -7.948603000-1.683852000-0.055384000 H -8.738831000-2.415603000-0.121853000 S -6.319644000-2.149454000-0.405759000 Crystallographic supplementary material Complex 3: Crystal data and structure refinement Table S1. Crystal data and structure refinement for 3 Empirical formula C 13 H 11 MoNO 6 Formula weight 373.17 Temperature 150(2) K Wavelength 0.71073 Å Crystal system Orthorhombic Space group Ama2 Unit cell dimensions a = 7.8219(5) Å = 90 b = 12.5022(8) Å = 90 c = 14.6697(10) Å = 90 Volume 1434.56(16) Å 3 Z 4 Density (calculated) 1.728 Mg/m 3 Absorption coefficient 0.940 mm -1 F(000) 744 Crystal size 0.366 x 0.174 x 0.140 mm 3 Theta range for data collection 3.259 to 26.013. S15

Index ranges -9<=h<=9, -15<=k<=15, -18<=l<=18 Reflections collected 23231 Independent reflections 1521 [R(int) = 0.0456] Completeness to theta = 25.242 99.5 % Absorption correction Semi-empirical from equivalents Max. and min. transmission 0.7471 and 0.6888 Refinement method Full-matrix least-squares on F 2 Data / restraints / parameters 1521 / 68 / 100 Goodness-of-fit on F 2 1.262 Final R indices [I>2sigma(I)] R1 = 0.0428, wr2 = 0.1062 R indices (all data) R1 = 0.0437, wr2 = 0.1069 Absolute structure parameter 0.5(2) Extinction coefficient n/a Largest diff. peak and hole 0.964 and -1.651 e.å -3 Complex 4: Crystal data and structure refinement Table S2. Crystal data and structure refinement for 4 Empirical formula C 16 H 10 MoO 6 S 2 Formula weight 458.30 Temperature 150(2) K Wavelength 0.71073 Å Crystal system Triclinic Space group P Unit cell dimensions a = 7.5179(18) Å = 91.950(8) b = 9.649(3) Å = 91.280(7) c = 25.060(7) Å = 94.945(8) Volume 1809.5(9) Å 3 Z 4 Density (calculated) 1.682 Mg/m 3 Absorption coefficient 0.984 mm -1 F(000) 912 Crystal size 0.318 x 0.095 x 0.038 mm 3 Theta range for data collection 2.243 to 26.430. Index ranges -9<=h<=9, -12<=k<=12, -31<=l<=31 Reflections collected 73188 Independent reflections 7424 [R(int) = 0.0621] Completeness to theta = 25.242 99.9 % S16

Refinement method Full-matrix least-squares on F 2 Data / restraints / parameters 7424 / 0 / 453 Goodness-of-fit on F 2 1.029 Final R indices [I>2sigma(I)] R1 = 0.0315, wr2 = 0.0562 R indices (all data) R1 = 0.0514, wr2 = 0.0609 Extinction coefficient n/a Largest diff. peak and hole 0.456 and -0.364 e.å -3 S17

Complex 5: Crystal data and structure refinement Table S3. Crystal data and structure refinement for 5 Empirical formula C 29 H 23 MoO 5 PS Formula weight 610.44 Temperature 150(2) K Wavelength 0.71073 Å Crystal system Monoclinic Space group P2 1 /n Unit cell dimensions a = 10.0549(6) Å = 90 b = 27.9556(16) Å = 112.910(2) c = 10.5193(6) Å = 90 Volume 2723.6(3) Å 3 Z 4 Density (calculated) 1.489 Mg/m 3 Absorption coefficient 0.654 mm -1 F(000) 1240 Crystal size 0.364 x 0.344 x 0.262 mm 3 Theta range for data collection 2.225 to 25.349. Index ranges -12<=h<=12, -33<=k<=33, -12<=l<=12 Reflections collected 70387 Independent reflections 4995 [R(int) = 0.0513] Completeness to theta = 25.242 99.9 % Refinement method Full-matrix least-squares on F 2 Data / restraints / parameters 4995 / 1 / 341 Goodness-of-fit on F 2 0.955 Final R indices [I>2sigma(I)] R1 = 0.0312, wr2 = 0.0712 R indices (all data) R1 = 0.0404, wr2 = 0.0750 Extinction coefficient n/a Largest diff. peak and hole 0.940 and -0.781 e.å -3 S18

Complex 7: Crystal data and structure refinement Table S4. Crystal data and structure refinement for 7 Empirical formula C 30 H 26 MoNO 5 P Formula weight 607.43 Temperature 150(2) K Wavelength 0.71073 Å Crystal system Monoclinic Space group P2 1 /n Unit cell dimensions a = 10.339(15) Å = 90 b = 27.56(5) Å = 114.10(4) c = 10.34(2) Å = 90 Volume 2690(8) Å 3 Z 4 Density (calculated) 1.500 Mg/m 3 Absorption coefficient 0.588 mm -1 F(000) 1240 Crystal size 0.391 x 0.255 x 0.092 mm 3 Theta range for data collection 2.280 to 27.369. Index ranges -13<=h<=13, -35<=k<=35, -13<=l<=13 Reflections collected 115844 Independent reflections 6012 [R(int) = 0.0398] Completeness to theta = 25.242 99.9 % Refinement method Full-matrix least-squares on F 2 Data / restraints / parameters 6012 / 0 / 343 Goodness-of-fit on F 2 1.083 Final R indices [I>2sigma(I)] R1 = 0.0288, wr2 = 0.0641 R indices (all data) R1 = 0.0337, wr2 = 0.0660 Extinction coefficient n/a Largest diff. peak and hole 0.861 and -0.514 e.å -3 S19

Complex 8: Crystal data and structure refinement Table S5. Crystal data and structure refinement for 8 Empirical formula C 33 H 25 MoO 5 PS 2 Formula weight 692.56 Temperature 150(2) K Wavelength 0.71073 Å Crystal system Triclinic Space group P Unit cell dimensions a = 9.434(6) Å = 96.54(3) b = 11.585(9) Å = 105.12(2) c = 15.838(13) Å = 112.79(2) Volume 1494.9(19) Å 3 Z 2 Density (calculated) 1.539 Mg/m 3 Absorption coefficient 0.673 mm -1 F(000) 704 Crystal size 0.495 x 0.169 x 0.158 mm 3 Theta range for data collection 2.404 to 27.370. Index ranges -12<=h<=12, -14<=k<=14, -20<=l<=20 Reflections collected 52451 Independent reflections 6692 [R(int) = 0.0278] Completeness to theta = 25.242 99.9 % Refinement method Full-matrix least-squares on F 2 Data / restraints / parameters 6692 / 0 / 379 Goodness-of-fit on F 2 1.086 Final R indices [I>2sigma(I)] R1 = 0.0211, wr2 = 0.0522 R indices (all data) R1 = 0.0247, wr2 = 0.0544 Largest diff. peak and hole 0.492 and -0.421 e.å -3 S20

Complex 9: Crystal data and structure refinement Table S6. Crystal data and structure refinement for 9 Empirical formula C 29 H 23 AsMoO 5 S Formula weight 654.39 Temperature 150(2) K Wavelength 0.71073 Å Crystal system Monoclinic Space group P2 1 /n Unit cell dimensions a = 10.188(5) Å = 90 b = 28.295(17) Å = 113.600(17) c = 10.623(8) Å = 90 Volume 2806(3) Å 3 Z 4 Density (calculated) 1.549 Mg/m 3 Absorption coefficient 1.748 mm -1 F(000) 1312 Crystal size 0.257 x 0.200 x 0.121 mm 3 Theta range for data collection 2.212 to 25.681. Index ranges -12<=h<=12, -34<=k<=34, -12<=l<=12 Reflections collected 70488 Independent reflections 5305 [R(int) = 0.0319] Completeness to theta = 25.242 99.7 % Absorption correction Semi-empirical from equivalents Max. and min. transmission 0.7457 and 0.6726 Refinement method Full-matrix least-squares on F 2 Data / restraints / parameters 5305 / 0 / 353 Goodness-of-fit on F 2 1.089 Final R indices [I>2sigma(I)] R1 = 0.0233, wr2 = 0.0550 R indices (all data) R1 = 0.0243, wr2 = 0.0556 Extinction coefficient n/a Largest diff. peak and hole 0.785 and -0.678 e.å -3 S21

Complex 10: Crystal data and structure refinement Table S7. Crystal data and structure refinement for 10 Empirical formula C 29 H 23 AsMoO 6 Formula weight 638.33 Temperature 150(2) K Wavelength 0.71073 Å Crystal system Monoclinic Space group P2 1 /c Unit cell dimensions a = 10.6239(3) Å = 90 b = 12.6559(4) Å = 102.229(2) c = 20.7243(7) Å = 90 Volume 2723.26(15) Å 3 Z 4 Density (calculated) 1.557 Mg/m 3 Absorption coefficient 1.728 mm -1 F(000) 1280 Crystal size 0.392 x 0.169 x 0.145 mm 3 Theta range for data collection 2.537 to 30.588. Index ranges -15<=h<=15, -18<=k<=18, -29<=l<=29 Reflections collected 119360 Independent reflections 8364 [R(int) = 0.0534] Completeness to theta = 25.242 99.9 % Refinement method Full-matrix least-squares on F 2 Data / restraints / parameters 8364 / 0 / 340 Goodness-of-fit on F 2 0.811 Final R indices [I>2sigma(I)] R1 = 0.0280, wr2 = 0.0681 R indices (all data) R1 = 0.0429, wr2 = 0.0784 Extinction coefficient n/a Largest diff. peak and hole 0.635 and -0.925 e.å -3 S22

Complex 12: Crystal data and structure refinement Table S8. Crystal data and structure refinement for 12 Empirical formula C 33 H 25 AsMoO 5 S 2 Formula weight 736.51 Temperature 151(2) K Wavelength 0.71073 Å Crystal system Triclinic Space group P Unit cell dimensions a = 9.5323(14) Å = 96.558(5) b = 11.7554(16) Å = 104.949(4) c = 15.9801(18) Å = 113.362(4) Volume 1540.2(4) Å 3 Z 2 Density (calculated) 1.588 Mg/m 3 Absorption coefficient 1.668 mm -1 F(000) 740 Crystal size 0.341 x 0.160 x 0.103 mm 3 Theta range for data collection 2.369 to 26.494. Index ranges -11<=h<=11, -14<=k<=14, -19<=l<=19 Reflections collected 68829 Independent reflections 6335 [R(int) = 0.0819] Completeness to theta = 25.242 99.9 % Refinement method Full-matrix least-squares on F 2 Data / restraints / parameters 6335 / 0 / 379 Goodness-of-fit on F 2 1.175 Final R indices [I>2sigma(I)] R1 = 0.0509, wr2 = 0.1235 R indices (all data) R1 = 0.0636, wr2 = 0.1281 Extinction coefficient n/a Largest diff. peak and hole 1.026 and -0.762 e.å -3 S23

Figures S 1 6 (Perspective drawings of 4b, 4c, 4d, 5b, 9b and 10b Figure S1. Perspective drawing of 4b, showing the atom numbering scheme. Atomic displacement parameters (ADP s) are shown at the 50% probability level. Figure S2. Perspective drawing of 4c, showing the atom numbering scheme. Atomic displacement parameters (ADP s) are shown at the 50% probability level. S24

Figure S3. Perspective drawing of 4d, showing the atom numbering scheme. Atomic displacement parameters (ADP s) are shown at the 50% probability level. Figure S4. Perspective drawing of 5b, showing the atom numbering scheme. Atomic displacement parameters (ADP s) are shown at the 50% probability level. S25

Figure S5. Perspective drawing of 9b, showing the atom numbering scheme. Atomic displacement parameters (ADP s) are shown at the 50% probability level. Figure S6. Perspective drawing of 10b, showing the atom numbering scheme. Atomic displacement parameters (ADP s) are shown at the 50% probability level. S26