Multimetallic complexes and functionalized nanoparticles based on unsymmetrical dithiocarbamate ligands with allyl and propargyl functionality.

The new, unsymmetrical dithiocarbamate ligands, KS2CN(CH2CH═CH2)Me and KS2CN(CH2C≡CH)Me, are formed from the respective amines on reaction with KOH and carbon disulfide. The homoleptic complexes [Ni{S2CN(CH2CH═CH2)Me}2] and [M{S2CN(CH2C≡CH)Me}2] (M = Ni, Pd, Pt) are formed on reaction with suitable metal precursors. Conversion between the two pendant functionalities was confirmed by hydrogenation of [Ni{S2CN(CH2C≡CH)Me}2] to yield [Ni{S2CN(CH2CH═CH2)Me}2]. The monodithiocarbamate compounds of group 8, 10, and 11 metals, [Ru{S2CN(CH2CH═CH2)Me}(dppm)2](+), [Ru(CH═CHC6H4Me-4){S2CN(CH2CH═CH2)Me}(CO)(PPh3)2], [Ni{S2CN(CH2CH═CH2)Me}(dppp)](+), and [Au{S2CN(CH2CH═CH2)Me}(PPh3)] were formed successfully. Using KS2CN(CH2C≡CH)Me, the complex [Ru{S2CN(CH2C≡CH)Me}(dppm)2](+) was obtained from cis-[RuCl2(dppm)2]. One palladium example, [Pd{S2CN(CH2C≡CH)Me}(PPh3)2](+), was also isolated in low yield. However, under the typical conditions employed, a rearrangement reaction prevented isolation of further group 10 propargyl-dithiocarbamate products. Over the extended reaction time required, Me(HC≡CCH2)NCS2(-) was found to undergo a remarkable, atom-efficient cyclization to form the thiazolidine-2-thione, H2C═CCH2N(Me)C(═S)S, in high yield, with MeC═CHN(Me)C(═S)S as the minor product. The reactivity of the pendant triple bonds in [Ni{S2CN(CH2C≡CH)Me}2] was probed in the reaction with [RuH(CO)(S2P(OEt)2)(PPh3)2] to form the trimetallic example [Ni{S2CN(Me)CH2CH═CHRu(CO)(S2P(OEt)2)(PPh3)2}2], while the copper(I) catalyzed reaction with benzylazide yielded the triazole product, [Ni{S2CN(Me)CH2(C2HN3)Bz}2]. KS2CN(CH2C≡CH)Me was also used to prepare the gold nanoparticles, Au@S2CN(CH2C≡CH)Me. Structural studies are reported for [Ru(CH═CHC6H4Me-4){S2CN(CH2CH═CH2)Me}(CO)(PPh3)2] and [Ru{S2CN(CH2C≡CH)Me}(dppm)2]PF6.

Ring-closing metathesis and nanoparticle formation based on diallyldithiocarbamate complexes of gold(I): synthetic, structural, and computational studies.

The gold(I) complexes [Au{S2CN(CH2CH═CH2)2}(L)] [L = PPh3, PCy3, PMe3, CN(t)Bu, IDip] are prepared from KS2CN(CH2CH═CH2)2 and [(L)AuCl]. The compounds [L2(AuCl)2] (L2 = dppa, dppf) yield [(L2){AuS2CN(CH2CH═CH2)2}2], while the cyclic complex [(dppm){Au2S2CN(CH2CH═CH2)2}]OTf is obtained from [dppm(AuCl)2] and AgOTf followed by KS2CN(CH2CH═CH2)2. The compound [Au2{S2CN(CH2CH═CH2)2}2] is prepared from [(tht)AuCl] (tht = tetrahydrothiophene) and the diallyldithiocarbamate ligand. This product ring-closes with [Ru(═CHPh)Cl2(SIMes)(PCy3)] to yield [Au2(S2CNC4H6)2], whereas ring-closing of [Au{S2CN(CH2CH═CH2)2}(PR3)] fails. Warming [Au2{S2CN(CH2CH═CH2)2}2] results in formation of gold nanoparticles with diallydithiocarbamate surface units, while heating [Au2(S2CNC4H6)2] with NaBH4 results in nanoparticles with 3-pyrroline dithiocarbamate surface units. Larger nanoparticles with the same surface units are prepared by citrate reduction of HAuCl4 followed by addition of the dithiocarbamate. The diallydithiocarbamate-functionalized nanoparticles undergo ring-closing metathesis using [Ru(═CHC6H4O(i)Pr-2)Cl2(SIMes)]. The interaction between the dithiocarbamate units and the gold surface is explored using computational methods to reveal no need for a countercation. Preliminary calculations indicate that the Au-S interactions are substantially different from those established in theoretical and experimental studies on thiolate-coated nanoparticles. Structural studies are reported for [Au{S2CN(CH2CH═CH2)2}(PPh3)] and [Au2{S2CN(CH2CH═CH2)2}2]. In the latter, exceptionally short intermolecular aurophilic interactions are observed.

Multimetallic complexes and functionalized nanoparticles based on oxygen- and nitrogen-donor combinations.

The versatile precursors [Ru(CH═CHC6H4Me-4)Cl(CO)(BTD)(PPh3)2] (BTD = 2,1,3-benzothiadiazole) and [Ru(C(C≡CPh)═CHPh)Cl(CO)(PPh3)2] were treated with isonicotinic acid, 4-cyanobenzoic acid, and 4-(4-pyridyl)benzoic acid under basic conditions to yield [Ru(vinyl)(O2CC5H4N)(CO)(PPh3)2], [Ru(vinyl)(O2CC6H4CN-4)(CO)(PPh3)2], and [Ru(vinyl){O2CC6H4(C5H4N)-4}(CO)(PPh3)2], respectively. The osmium analogue [Os(CH═CHC6H4Me-4)(O2CC5H4N)(CO)(PPh3)2] was also prepared. cis-[RuCl2(dppm)2] was used to prepare the cationic compounds [Ru(O2CC5H4N)(dppm)2](+) and [Ru{O2CC6H4(C5H4N)-4}(dppm)2](+). The treatment of 2 equiv of [Ru(C(C≡CPh)═CHPh)(O2CC5H4N)(CO)(PPh3)2] and [Ru(O2CC5H4N)(dppm)2](+) with AgOTf led to the trimetallic compounds [{Ru(C(C≡CPh)═CHPh)(CO)(PPh3)2(O2CC5H4N)}2Ag](+) and [{Ru(dppm)2(O2CC5H4N)}2Ag](3+). In a similar manner, the reaction of [Ru(O2CC5H4N)(dppm)2](+) with PdCl2 or K2PtCl4 yielded [{Ru(dppm)2(O2CC5H4N)}2MCl2](2+) (M = Pd, Pt). The reaction of [RuHCl(CO)(BTD)(PPh3)2] with HC≡CC6H4F-4 provided [Ru(CH═CHC6H4F-4)Cl(CO)(BTD)(PPh3)2], which was treated with isonicotinic acid and base to yield [Ru(CH═CHC6H4F-4)(O2CC5H4N)(CO)(PPh3)2]. The addition of [Au(C6F5)(tht)] (tht = tetrahydrothiophene) resulted in the formation of [Ru(CH═CHC6H4F-4){O2CC5H4N(AuC6F5)}(CO)(PPh3)2]. Similarly, [Ru(vinyl)(O2CC6H4CN-4)(CO)(PPh3)2] reacted with [Au(C6F5)(tht)] to provide [Ru(vinyl){O2CC6H4(CNAuC6F5)-4}(CO)(PPh3)2]. The reaction of 4-cyanobenzoic acid with [Au(C6F5)(tht)] yielded [Au(C6F5)(NCC6H4CO2H-4)]. This compound was used to prepare [Ru(CH═CHC6H4F-4){O2CC6H4(CNAuC6F5)-4}(CO)(PPh3)2], which was also formed on treatment of [Ru(CH═CHC6H4F-4)(O2CC6H4CN-4)(CO)(PPh3)2] with [Au(C6F5)(tht)]. The known compound [RhCl2(NC5H4CO2)(NC5H4CO2Na)3] and the new complex [RhCl2{NC5H4(C6H4CO2)-4}{NC5H4(C6H4CO2Na)-4}3] were prepared from RhCl3·3H2O and isonicotinic acid or 4-(4-pyridyl)benzoic acid, respectively. The former was treated with [Ru(CH═CHC6H4Me-4)Cl(CO)(BTD)(PPh3)2] to yield [RhCl2{NC5H4CO2(Ru(CH═CHC6H4Me-4)(CO)(PPh3)2}4]Cl. As an alternative route to pentametallic compounds, the Pd-coordinated porphyrin [(Pd-TPP)(p-CO2H)4] was treated with 4 equiv of [Ru(CH═CHR)Cl(CO)(BTD)(PPh3)2] in the presence of a base to yield [(Pd-TPP){p-CO2Ru(CH═CHR)(CO)(PPh3)2}4] (R = C6H4Me-4, CPh2OH). Where R = CPh2OH, treatment with HBF4 led to the formation of [(Pd-TPP){p-CO2Ru(═CHCH═CPh2)(CO)(PPh3)2}4](BF4)4. [(Pd-TPP){p-CO2Ru(dppm)2}4](PF6)4 was prepared from [(Pd-TPP)(p-CO2H)4] and cis-[RuCl2(dppm)2]. The reaction of AgNO3 with sodium borohydride in the presence of [Ru(O2CC5H4N)(dppm)2](+) or [RuR{O2CC6H4(C5H4N)-4}(dppm)2](+) provided silver nanoparticles Ag@[NC5H4CO2Ru(dppm)2](+) and Ag@[NC5H4{C6H4CO2Ru(dppm)2}-4](+).

Dithiocarboxylate complexes of ruthenium(II) and osmium(II).

The ruthenium(II) complexes [Ru(R)(κ(2)-S(2)C·IPr)(CO)(PPh(3))(2)](+) (R = CH=CHBu(t), CH=CHC(6)H(4)Me-4, C(C≡CPh)=CHPh) are formed on reaction of IPr·CS(2) with [Ru(R)Cl(CO)(BTD)(PPh(3))(2)] (BTD = 2,1,3-benzothiadiazole) or [Ru(C(C≡CPh)=CHPh)Cl(CO)(PPh(3))(2)] in the presence of ammonium hexafluorophosphate. Similarly, the complexes [Ru(CH=CHC(6)H(4)Me-4)(κ(2)-S(2)C·ICy)(CO)(PPh(3))(2)](+) and [Ru(C(C≡CPh)=CHPh)(κ(2)-S(2)C·ICy)(CO)(PPh(3))(2)](+) are formed in the same manner when ICy·CS(2) is employed. The ligand IMes·CS(2) reacts with [Ru(R)Cl(CO)(BTD)(PPh(3))(2)] to form the compounds [Ru(R)(κ(2)-S(2)C·IMes)(CO)(PPh(3))(2)](+) (R = CH=CHBu(t), CH=CHC(6)H(4)Me-4, C(C≡CPh)=CHPh). Two osmium analogues, [Os(CH=CHC(6)H(4)Me-4)(κ(2)-S(2)C·IMes)(CO)(PPh(3))(2)](+) and [Os(C(C≡CPh)=CHPh)(κ(2)-S(2)C·IMes)(CO)(PPh(3))(2)](+) were also prepared. When the more bulky diisopropylphenyl derivative IDip·CS(2) is used, an unusual product, [Ru(κ(2)-SC(H)S(CH=CHC(6)H(4)Me-4)·IDip)Cl(CO)(PPh(3))(2)](+), with a migrated vinyl group, is obtained. Over extended reaction times, [Ru(CH=CHC(6)H(4)Me-4)Cl(BTD)(CO)(PPh(3))(2)] also reacts with IMes·CS(2) and NH(4)PF(6) to yield the analogous product [Ru{κ(2)-SC(H)S(CH=CHC(6)H(4)Me-4)·IMes}Cl(CO)(PPh(3))(2)](+)via the intermediate [Ru(CH=CHC(6)H(4)Me-4)(κ(2)-S(2)C·IMes)(CO)(PPh(3))(2)](+). Structural studies are reported for [Ru(CH=CHC(6)H(4)Me-4)(κ(2)-S(2)C·IPr)(CO)(PPh(3))(2)]PF(6) and [Ru(C(C≡CPh)=CHPh)(κ(2)-S(2)C·ICy)(CO)(PPh(3))(2)]PF(6).

Gold(I) complexes bearing mixed-donor ligands derived from N-heterocyclic carbenes.

The new 2-phenylthiocarbamoyl-1,3-dimesitylimidazolium inner salt (IMes·CSNPh) reacts with [AuCl(L)] in the presence of NH(4)PF(6) to yield [(L)Au(SCNPh·IMes)](+) (L = PMe(3), PPh(3), PCy(3), CNBu(t)). The carbene-containing precursor [(IDip)AuCl] reacts with IMes·CSNPh under the same conditions to afford the complex [(IDip)Au(SCNPh·IMes)](+) (IDip = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene). Treatment of the diphosphine complex [(dppm)(AuCl)(2)] with one equivalent of IMes·CSNPh yields the digold metallacycle, [(dppm)Au(2)(SCNPh·IMes)](2+), while reaction of [L(2)(AuCl)(2)] with two equivalents of IMes·CSNPh results in [(L(2)){Au(SCNPh·IMes)}(2)](2+) (L(2) = dppb, dppf, or dppa; dppb = 1,4-bis(diphenylphosphino)butane, dppf = 1,1'-bis(diphenylphosphino)ferrocene, dppa = 1,4-bis(diphenylphosphino)acetylene). The homoleptic complex [Au(SCNPh·IMes)(2)](+) is formed on reaction of [AuCl(tht)] (tht = tetrahydrothiophene) with two equivalents of the imidazolium-2-phenylthiocarbamoyl ligand. This product reacts with AgOTf to yield the mixed metal compound [AuAg(SCNPh·IMes)(2)](2+). Over time, the unusual trimetallic complex [Au(AgOTf)(2)(SCNPh·IMes)(2)](+) is formed. The sulfur-oxygen mixed-donor ligands IMes·COS and SIMes·COS (SIMes = 1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene) were used to prepare [(L)Au(SOC·IMes)](+) and [(L)Au(SOC·SIMes)](+) from [(L)AuCl] (L = PPh(3), CN(t)Bu). The bimetallic examples [(dppf){Au(SOC·IMes)}(2)](2+) and [(dppf){Au(SOC·SIMes)}(2)](2+) were synthesized from the reaction of [(dppf)(AuCl)(2)] with the appropriate ligand. Reaction of [(tht)AuCl] with one equivalent of IMes·COS or SIMes·COS yields [Au(SOC·IMes)(2)](+) and [Au(SOC·SIMes)(2)](+), respectively. The compounds [(Ph(3)P)Au(SCNPh·IMes)]PF(6), [(Cy(3)P)Au(SCNPh·IMes)]PF(6) and [Au(AgOTf)(2)(SCNPh·IMes)(2)]OTf were characterized crystallographically.

The functionalisation of ruthenium(II) and osmium(II) alkenyl complexes with amine- and alkoxy-terminated dithiocarbamates.

The complex cis-[RuCl(2)(dppm)(2)] reacts with the amine-terminated dithiocarbamates KS(2)CN(CH(2)CH(2)NEt(2))(2) and KS(2)CN(CH(2)CH(2)CH(2)NMe(2))(2) to form the compounds [Ru{S(2)CN(CH(2)CH(2)NEt(2))(2)}(dppm)(2)](+) and [Ru{S(2)CN(CH(2)CH(2)CH(2)NMe(2))(2)}(dppm)(2)](+), respectively. The methoxy-terminated dithiocarbamate compound [Ru{S(2)CN(CH(2)CH(2)OMe)(2)}(dppm)(2)](+) was also prepared from the same precursor using KS(2)CN(CH(2)CH(2)OMe)(2). The alkenyl complexes [RuRCl(CO)(BTD)(PPh(3))(2)] (R = CH=CHBu(t), CH=CHC(6)H(4)Me-4, CH=CHCPh(2)OH), [Ru(C(C[triple bond]CBu(t))=CHBu(t))Cl(CO)(PPh(3))(2)] and [Os(CH=CHC(6)H(4)Me-4)Cl(CO)(BTD)(PPh(3))(2)] also react cleanly with KS(2)CN(CH(2)CH(2)CH(2)NMe(2))(2) and KS(2)CN(CH(2)CH(2)NEt(2))(2) to yield [MR{S(2)CN(CH(2)CH(2)CH(2)NMe(2))(2)}(CO)(PPh(3))(2)] and [MR{S(2)CN(CH(2)CH(2)NEt(2))(2)}(CO)(PPh(3))(2)], respectively. In a similar fashion, the compounds [RuR{S(2)CN(CH(2)CH(2)OMe(2))(2)}(CO)(PPh(3))(2)] (R = CH=CHBu(t), CH=CHC(6)H(4)Me-4, C(C[triple bond]CBu(t))=CHBu(t)) were also prepared. Treatment of [Ru(CH=CHBu(t)){S(2)CN(CH(2)CH(2)CH(2)NMe(2))(2)}(CO)(PPh(3))(2)] and [Ru{S(2)CN(CH(2)CH(2)NEt(2))(2)}(dppm)(2)](+) with trifluoroacetic acid affords the ammonium complexes [Ru(CH=CHBu(t)){S(2)CN(CH(2)CH(2)CH(2)NHMe(2))(2)}(CO)(PPh(3))(2)](2+) and [Ru{S(2)CN(CH(2)CH(2)NHEt(2))(2)}(dppm)(2)](2+), while the same reagent generates the tricationic vinylcarbene complex [Ru(=CHCH=CPh(2)){S(2)CN(CH(2)CH(2)CH(2)NHMe(2))(2)}(CO)(PPh(3))(2)](3+) through loss of water from [Ru(CH=CHCPh(2)OH){S(2)CN(CH(2)CH(2)CH(2)NMe(2))(2)}(CO)(PPh(3))(2)]. The structures of [Ru{S(2)CN(CH(2)CH(2)OMe)(2)}(dppm)(2)]PF(6) and [Ru(CH=CHC(6)H(4)Me-4){S(2)CN(CH(2)CH(2)OMe)(2)}(CO)(PPh(3))(2)] were determined crystallographically.

The use of imidazolium-2-dithiocarboxylates in the formation of gold(I) complexes and gold nanoparticles.

The imidazolium-2-dithiocarboxylate ligands IPr.CS(2), IMes.CS(2), and IDip.CS(2) react with [AuCl(PPh(3))] to yield [(Ph(3)P)Au(S(2)C.IPr)](+), [(Ph(3)P)Au(S(2)C.IMes)](+), and [(Ph(3)P)Au(S(2)C.IDip)](+), respectively. The compounds [(L)Au(S(2)C.IMes)](+) are prepared from the reaction of IMes.CS(2) with [AuCl(L)] (L = PMe(3), PCy(3), CN(t)Bu). The carbene-containing precursor [(IDip)AuCl] reacts with IPr.CS(2) and IMes.CS(2) to afford the complexes [(IDip)Au(S(2)C.IPr)](+) and [(IDip)Au(S(2)C.IMes)](+) with two carbene units, one bound to the metal center and the other to the dithiocarboxylate unit. Treatment of the diphosphine-gold complex [(dppm)(AuCl)(2)] with 1 equiv of IMes.CS(2) yields [(dppm)Au(2)(S(2)C.IMes)](2+), while the reaction of [L(2)(AuCl)(2)] (L(2) = dppb, dppf) with 2 equiv of IMes.CS(2) results in [(L(2)){Au(S(2)C.IMes)}(2)](2+). The homoleptic complexes [Au(S(2)C.IPr)(2)](2+), [Au(S(2)C.IMes)(2)](2+), and [Au(S(2)C.IDip)(2)](2+) are obtained from the reaction of [AuCl(tht)] with 2 equiv of the appropriate imidazolium-2-dithiocarboxylate ligand. The compounds [(Ph(3)P)Au(S(2)C.NHC)](+) (NHC = IMes, IDip) and [(IDip)Au(S(2)C.NHC)](+) (NHC = IPr, IMes) are characterized crystallographically. The IMes.CS(2) ligand is also used to prepare functionalized gold nanoparticles with diameters of 11.5 (+/-1.2) and 2.6 (+/-0.3) nm.