Daniel Miguel

Substituted seven-coordinate molybdenum-tin and tungsten-tin complexes from M(CO)6, BuSnCl3 and phosphites. X-ray structure of [Mo(CO)2{P(OMe)3}3(SnBuCl2)Cl]

Abstract BuSnCl 3 reacts with [M(CO) 3 (NCR) 3 ] (M = Mo, R = Me; M = W, R = Et) to produce [M(CO) 3 (NCR) 2 (SnCl 2 Bu)Cl]. These complexes react further with three molar-equivalents of P(OR′) 3 (R′ = Me, Et) at room temperature giving dicarbonyl tris-phosphite complexes [M(CO) 2 {P(OR′) 3 } 3 (SnCl 2 Bu)Cl] through displacement of the two nitrile ligands and one CO group. The molybdenum compounds can be prepared in high yields by a one-pot, two-step synthesis by heating [M(CO) 6 ] with BuSnCl 3 in acetonitrile, and then adding the phosphite to the resulting solution. Similar reactions with SnCl 2 Bu 2 and SnCl 2 Ph 2 have been explored.

Seven-coordinate molybdenum-tin and tungsten-tin complexes containing phosphates and tetramethylthiourea: X-ray structure of [Mo(CO)2{P(OMe)3}3 (SnBuCl2)Cl]

Abstract [M(CO) 3 (nitrile) 3 ] react with SnRCl 3 (R  Bu or Ph) to produce [M(CO) 3 (nitrile) 2 (SnRCl 2 )Cl] ( 1 ; M  Mo, nitrile = NCMe; M  W, nitrile = NCEt). These complexes react further with three equivalents of phosphite P(OR′) 3 (R′  Me or Et) at room temperature giving dicarbonyl tris (phosphite) complexes [M(CO) 2 {P(OR′) 3 } 3 /(SnRCl 2 )Cl] ( 2 ; M  Mo or W; R  Bu or Ph; R′  Me or Et) through displacement of the two nitriles and one CO. The dicarbonyl tris(phosphite) complexes are produced even when only two equivalents of phosphite are added to the reaction mixture. In contrast, when the tricarbonyl bis(nitrile) compounds 1 react with an excess of tretramethylthiourea (TMTU), only the two nitriles are replaced, leading to tricarbonyls [M(CO) 3 (TMTU) 2 (SnRCl 2 )Cl] ( 3 , M  Mo or W; R  Bu or Ph).

η3-Allyl molybdenum dithiophosphate and dithiophosphinate complexes with uni- and bidentate nitrogen donor ligands. X-ray structure of [Mo2(η3-C3H5)2(CO)4{S2P(OEt)2}2(μ-NH2NH2)]

Abstract The bis(nitrile) complex [Mo( η 3 -C 3 H 5 )(CO) 2 (NCMe) 2 Br] ( 1 ) reacts with ammonium diethyldithiophosphate or sodium diphenyldithiophosphinate to afford [Mo( η 3 -C 3 H 5 )(CO) 2 (S 2 PX 2 )(NCMe)] ( 2 , X = OEt or Ph). The labile nitrile ligand in these complexes can be replaced by unidentate N-donors, L, affording mononuclear [Mo( η 3 -C 3 H 5 )(CO) 2 (S 2 PX 2 )(L)] ( 3 , L = 4-NH 2 C 6 H 4 Me or py). Reactions of 2 with 0.5 equiv. of bidentate donors such as hydrazine or pyrazine produces binuclear complexes [Mo 2 ( η 3 -C 3 H 5 ) 2 (CO) 4 (S 2 PX 2 ) 2 ( μ -NN)] ( 4 , NN = N 2 H 4 or pyrazine). An X-ray structure determination carried out on [Mo 2 ( η 3 -C 3 H 5 ) 2 (CO) 4 {S 2 P(OEt) 2 } 2 ( μ -NH 2 NH 2 )] ( 4a ), showed the hydrazine bridge holding together two pseudo-octahedral ‘Mo( η 3 -C 3 H 5 )(CO) 2 {S 2 P(OEt) 2 } 2 ’ fragments.

Seven-coordinate molybdenum complexes containing SnRCl2 and phosphorodithioate. X- Ray structure of [Mo(CO)2{P(OMe)3}2{S2P(OEt)2}(SnBuCl2)]

Abstract [Mo(CO)3(NCMe)2(SnRCl2)Cl] (1a, R  Ph; 1b, R  Bu) react with ammonium diethyldithiophosphate or with sodium dipheny

The first cationic heterobinuclear complexes with bridging S2CPR3 ligands. X-ray structure of [(η6-C6Me6)Ru(μ-Cl)(μ-S2CPCy3)W(CO)3]PF6 · CH2Cl2

Abstract Complexes [(η6-C6Me6)Ru(μ-Cl)(μ-S2CPCy3)M(CO)3]+, which are the first examples of cationic heterobinuclear complexes containing S2CPR3 bridges, and also the first to contain S2CPR3 ligands acting as η3(S,C,S′) ligand towards a metal other than molybdenum or manganese, have been prepared by reaction of [(η6-C6Me6)Ru(S2CPCy3)Cl]PF6 with [M(CO)3(NCR)3] (M = Mo, W), and shown to be stable enough to maintain the dinuclear unit through several reactions involving the displacement of CO.

Heterodinuclear complexes of rhenium and molybdenum with bridging S2CPR3 ligands

Abstract Mononuclear complexes fac -[RC(CO) 3 (S 2 CPR 3 )Br](R = cyclohexyl(Cy)( 1a ) or isopropyl ( i Pr) ( 1b )) react with [Mo(CO) 3 (NCMe) 3 ] to afford dinuclear complexes of formula [ReMo(CO) 6 (μ-Br)(μ-S 2 CPR 3 )] (R = Cy ( 2a ) or i Pr ( 2b )). Treatment of complexes 2 with monodentate phosphorus donors such as PEt 3 or P(OMe) 3 displaces one carbonyl ligand from the molybdenum atom, to afford pentacarbonyls [ReMo(CO) 5 (μ-Br)(μ-S 2 CPR 3 )(L)] ( 3a–3d ). Reactions of 2 with bidentate phosphorus donors displace one CO group from molybdenum and cleave one ReS bond to give pentacarbonyls [ReMo(CO) 5 (μ-Br)(μ-S 2 CPR 3 )(μ-L-L)] ( 4a–4d ) (L-L = tetraethylpyrophosphite or bis(dimethylphosphino)methane), in which the S 2 CPR 3 bridges have changed their coordination mode from η 2 ( S,S,′ )η 3 ( S,C,S,′ ) to η 1 ( S )η 3 ( S,C,S,′ ).

Ring opening and closing in (CO)n(L)MnI complexes where L = S2CPCy3 or diphosphine. Novel complexes containing the Mn(μ-L)AuC6F5 entity where L = S2CPCy3 or dppm

Abstract The four-membered Mc-S-C-S ring in complexes containing S 2 CPCy 3 chelate ligands are opened very easily when the complexes are treated with phosphites, isocyanides or diphosphines, to give complexes in which the S 2 CPCy 3 entity is monodentate. In some cases, the resulting complexes undergo intramolecular displacement of CO by the uncoordinated sulfur with closing of the Mn-S-C-S ring. The uncoordinated sulfur in cationic complexes in which S 2 CpCy 3 is monodentate, appears to be a poor nucleophile, and fails to bind a second metal to give four-electron bridges. Treatment of fac -[Mn(CO) 3 (dppm){SC(S)PCy 3 }]PF 6 with [(tht)AuC 6 F 5 ), causes opening of the chelate ring of the diphosphine dppm, and simultaneous closing of the ring of the S 2 CPCy 3 ligand to give [S 2 CPCy 3 )(CO) 3 Mn(μ-dppm)Au(C 6 F 5 )[PF 6 . However, the complex [(η 5 -C 5 H 4 -Me)(CO) 2 MnSC(PCy 3 )SAu(C 6 F 5 )], containing the first example of a η 1 (S′), S 2 CPCy 3 four-electron bridge between two different metals, can be prepared from [Mn(η 5 -C 5 H 4 Me)(CO) 2 (SC(S)PCy 3 )] and [Au(C 6 F 5 )(tht)].

Seven-coordinate molybdenum-tin complexes containing phosphorodithioato and phosphoniodithioformate. X-Ray structure of [Mo(CO)2S2P(OEt)2(S2CPCy3)(SnPhCl2)] · CH2Cl2

Abstract Reactions of [Mo(CO) 3 (NCMe)(S 2 PX 2 )(SnRCl 2 )] ( 1 ) with an excess of S 2 CPR 3 afford complexes [Mo(CO) 2 (S 2 PX 2 )(S 2 CPR′3)-(SnRCl 2 )] ( 2 ; R = Ph or Bu; X = OEt or Ph; R′ = Cy or i Pr). An X-ray structure analysis of [Mo(CO) 2 S 2 P (OEt) 2 (S 2 CPCy 3 )-(SnPhCl 2 )] ( 3a ) showed that both sulphur ligands chelate molybdenum. Additionally, one sulphur atom of the S 2 CPR 3 group is within bonding distance of the tin atom, and thus bridges molybdenum and tin.

Reduction reactions of binuclear manganese-molybdenum complexes containing S2CPR3 and bidentate P-donor bridges. X-Ray structure of [MnMo(SnPh3)(CO)4(μ-tedip)(μ-S2CPCy3)]

The reduction of the substituted derivatives [MnMo(CO)5(μ-Br)(μ-L-L)(μ-S2CPR3)] (1, L-L = dmpm or tedip), with produces anions (2) that, upon reaction with ClSnPh3, give neutral tetracarbonyls [MnMo(SnPh3)(CO)4(μ-L-L)(μ-S2CPR3)] (3). An X-ray structure determination of 3a (L-L = tedip, RCy) demonstrates the addition of SnPh3 to Mo and migration of the central carbon atom of the S2CPR3 from Mo to Mn. Simultaneous loss of one carbonyl group from the manganese atom allows a change of coordination of S2CPR3 from η1;η3 (in 1) to η3;η2 (in 3). The tetracarbonyls 3 can also be prepared by reaction of the triphenylstannylhexacarbonyl derivatives [MnMo(CO)6(SnPh3)(μ-S2CPR3)] with bidentate donors L-L (dmpm or tedip), through substitution of one CO group on each metal.

The first examples of insertion of SnCl2 into the MnCl and ReCl bonds of octahedral complexes: X-ray structure of [Mn(CO)3(SnCl3)(S2CPCy3)] · CH2Cl 2

Compounds fac-[M(CO)3(S2CPR3)Cl] (M  Mn or Re; R = cyclohexyl or isopropyl) react with SnCl2 in tetrahydrofuran (THF) within 30 min to give trichlorostannyl complexes fac-[M(CO)3(S2CPR3)(SnCl3)], these being the first examples of a direct insertion of SnCl2 into MnCl or ReCl bonds of octahedral carbonyl complexes. The structure of the trichlorostannyl derivative of manganese (R = cyclohexyl) has been determined by X-ray diffraction. Several experimental facts suggest that the facile insertion of SnCl2 in the starting fac- [M(CO)3(S2CPR3)Cl] complexes should be attributed to the presence of the S2CPR3 ligands.