Platinum thiosemicarbazide and thiourea complexes: the crystal structure of [PtCl(dppe){SC(NHMe)NHNMe2-S}](PF6) and the influence of intramolecular hydrogen bonding on ligand co-ordination mode

The reaction of [PtCl₂(dppe)] [dppe=1,2-bis(diphenylphosphino)ethane] with two equivalents of the thioureas NHRC(S)NHR (R=H, Me, Et) in the presence of NH₄PF₆ led to substitution of both chlorides and formation of the complexes [Pt(dppe){SC(NHR)₂}₂](PF₆)₂ (1a, R=H; 1b, R=Me; 1c, R=Et). In contrast, the reaction of [PtCl₂(dppe)] with one equivalent of the potentially bidentate thiosemicarbazides NHRC(S)NHNR′₂ (R=Me, R′=H; R=Et, R′=H; R=Ph, R′=H; R=Me, R′=Me) in the presence of NH₄PF₆ led to substitution of only one chloride and formation of the complexes [PtCl(dppe){SC(NHR)NHNR₂′-S}](PF₆) (2a, R=Me, R′=H; 2b, R=Et, R′=H; 2c, R=Ph, R′=H; 2d, R=Me, R′=Me). An X-ray analysis of complex 2d revealed that an intramolecular N–H⋯Cl hydrogen bond [N(2)⋯Cl(1)=3.29(2) Å] helps to stabilise the monodentate co-ordination mode. The chloride ligand can be abstracted from complex 2d by treatment with TlPF₆, and this reaction led to formation of [Pt(dppe){SC(NHMe)NHNMe₂-S,N}](PF₆)₂ 3d. Reaction of [PtCl₂(dppe)] with unsubstituted thiosemicarbazide NH₂C(S)NHNH₂ in the presence of NH₄PF₆ resulted in a mixture of products containing mono- and bidentate co-ordinated ligands, [PtCl(dppe){SC(NH₂)NHNH₂-S}](PF₆) 2e and [Pt(dppe){SC(NH₂)NHNH₂-S,N}](PF₆)₂ 3e. [PtCl₂(dppe)] also reacts with two equivalents of NHMeC(S)NHNMe₂ in the presence of NH₄PF₆ to yield [Pt(dppe){SC(NHMe)NHNMe₂-S}₂](PF₆)₂ 1d, in which the thiosemicarbazide is acting as an S-donor, directly analogous to the thiourea ligands in complexes 1a–c.     

Reactions at the B–B Bond of Bis(trisyl)oxadiborirane: Ring Extensions

The B–B bond of bis(trisyl)oxadiborirane OB₂R₂ (R = C(SiMe₃)₃) is opened by amides R′CO(NHR″) to give the dioxaazadiboracyclohexanes [–BR–O–BR–NR″–CHR′–O–] (R′/R″ = H/H, H/Me, H/Et, Me/H: 5 a – d ). The amide MeCO(NHMe) yields 5 e (R′/R″ = Me/Me), when an excess of the amide is applied for 24 h, but yields an isomeric 1 : 1 adduct ( 6 e ), when a stoichiometric amount of the amide is applied for 15 h; upon refluxing this isomer in hexane, it is transformed into 5 e .     

Synthesis and Characterization of Three Homoleptic Bismuth Silanolates: [Bi(OSiR3)3] (R = Me,Et, iPr)

The bismuth tris(triorganosilanolates) [Bi(OSiR₃)₃] ( 1 , R = Me; 2 , R = Et; 3 , R = iPr) were prepared by reaction of R₃SiOH with [Bi(OtBu)₃]. Compound 1 crystallizes in the triclinic space group with Z = 2 and the lattice constants a = 10.323(1) Å, b = 13.805(1) Å, c = 21.096(1) Å and α = 91.871(4)°, β = 94.639(3)°, γ = 110.802(3)°. In the solid state compound 1 is a trimer as result of weak intermolecular bismuth‐oxygen interactions with Bi–O distances in the range 2.686(6)–3.227(3) Å. The coordination at the bismuth atoms Bi(1) and Bi(3) is best described as 3 + 2 coordination whereas Bi(2) shows a 3 + 3 coordination. The intramolecular Bi–O distances fall in the range 2.041(3)–2.119(3) Å. Compound 3 crystallizes in the orthorhombic space group Pbcm with Z = 4 and the lattice constants a = 7.201(1) Å, b = 23.367(5) Å and c = 20.893(1) Å, whereas the triethylsilyl‐derivative 2 is liquid. In contrast to [Bi(OSiMe₃)₃] ( 1 ) compound 3 is monomeric in the solid state, but shows similar intramolecular Bi–O distances in the range 1.998(2)–2.065(5) Å. The bismuth silanolates are highly soluble in common organic solvents and strongly moisture sensitive. Compound 1 shows the lowest thermal stability.     

Stabilization of a Silaaldehyde by its η2 Coordination to Tungsten

Treatment of pyridine‐stabilized silylene complexes [(η⁵‐C₅Me₄R)(CO)₂(H)W?SiH(py)(Tsi)] (R=Me, Et; py=pyridine; Tsi=C(SiMe₃)₃) with an N‐heterocyclic carbene ^MeIⁱPr (1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene) caused deprotonation to afford anionic silylene complexes [(η⁵‐C₅Me₄R)(CO)₂W?SiH(Tsi)][H^MeIⁱPr] (R=Me ( 1‐Me ); R=Et ( 1‐Et )). Subsequent oxidation of 1‐Me and 1‐Et with pyridine‐N‐oxide (1 equiv) gave anionic η²‐silaaldehydetungsten complexes [(η⁵‐C₅Me₄R)(CO)₂W{η²‐O?SiH(Tsi)}][H^MeIⁱPr] (R=Me ( 2‐Me ); R=Et ( 2‐Et )). The formation of an unprecedented W‐Si‐O three‐membered ring was confirmed by X‐ray crystal structure analysis.     

Alcohol Solvates of Lanthanoid(III) Trifluoromethanesulfonates

After vacuum dehydration, a number of hydrated trivalent lanthanoid trifluoromethanesulfonates (“triflate”, “OTf” = F₃CSO₃), when recrystallized from various alcohol (ROH) solutions, yield solvates Ln(OTf)₃ · xROH, x = 3, 5 or 6. The following have been defined crystallographically (R/Ln/x): Me/La/3;Me/Gd/6; Et/Sm/3; Et/Gd/5 iPr/Nd,Sm/3. The Me/Gd/6complex, Gd(OTf)₃ · 6MeOH is a mononuclear/ionic form [(MeOH)₆Gd(O–OTf)₂](OTf), the gadolinium environment being octacoordinate, square‐antiprismatic with the O–OTf donors quasi‐trans on different faces of the coordination polyhedron; the Et/Gd/5 complex is neutral, molecular, mononuclear [(EtOH)₅Gd(O–OTf)₃], also with an octacoordinate, square‐antiprismatic coordination sphere, derivative of that of the methanol solvate. The remainder form one‐dimensional polymeric arrays, successive lanthanoid atoms linked by (μ‐O–OTf–O′)₃ triads, at either end of a tricapped trigonal prismatic array, the ROH molecules contributing the capping atoms. A (“baseline”) (re‐)determination of the “parent” Sm(OTf)₃ · 9H₂O is also recorded.     

Living cationic polymerization route to poly(oligooxyethylene carbonate) vinyl ethers

The addition of dialkyl (R = Me or Et) carbonates to poly(oxyethylene)-based solid polymeric electrolytes resulted in enhanced ionic conductivities. Relatively high conductivities in lithium batteries with solutions of lithium salts in di(oligooxyethylene) carbonates such as R( OCH₂ CH₂ )_nOC(O) O ( CH₂CH₂O )_mR (R = Et, n = 1, 2, or 3, m = 0, 1, 2, or 3) and related carbonates were obtained. In this respect, related comb-shaped poly(oligooxyethylene carbonate) vinyl ethers of the type  CH₂CH(OR) were prepared [R = ( OCH₂ CH₂ )_nOC(O) O ( CH₂CH₂O )_mR′; (1) n = 2 or 3, m = 0, R′ = Et; (2) n = 2 or 3; m = 3, R′ = Me]. The direct preparation of derived target polymers of this class by polymerization of the corresponding vinyl ether-type monomers could not be achieved because of a rapid in situ decarboxylative decomposition of these monomers (as formed) during the final step of their synthesis. Instead, a prepolymer was prepared by a living cationic polymerization of CH₂CH (OCH₂CH₂ )_n O C(O) CH₃ (n = 2 or 3). The hydrolysis of its pendant ester groups, followed by the reaction of the hydrolyzed prepolymer with each of several alkyl chloroformates of the type Cl C(O) O( CH₂CH₂O )_mR′ (m = 0, 2, or 3, R′ = Me or Et) resulted in the corresponding target polymers. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2171–2183, 2002     

Dynamic Effects Dictate the Mechanism and Selectivity of Dehydration–Rearrangement Reactions of Protonated Alcohols [Me2(R)CCH(OH2)Me]+ (R=Me,Et, iPr) in the Gas Phase

The gas‐phase dehydration–rearrangement (DR) reactions of protonated alcohols [Me₂(R)CCH(OH₂)Me]⁺ [R=Me ( ME ), Et ( ET ), and iPr ( I‐PR )] were studied by using static approaches (intrinsic reaction coordinate (IRC), Rice–Ramsperger–Kassel–Marcus theory) and dynamics (quasiclassical trajectory) simulations at the B3LYP/6‐31G(d) level of theory. The concerted mechanism involves simultaneous water dissociation and alkyl migration, whereas in the stepwise reaction pathway the dehydration step leads to a secondary carbocation intermediate followed by alkyl migration. Internal rotation (IR) can change the relative position of the migrating alkyl group and the leaving group (water), so distinct products may be obtained: [Me(R)CCH(Me)Me ??? OH₂]⁺ and [Me(Me)CCH(R)Me ??? OH₂]⁺. The static approach predicts that these reactions are concerted, with the selectivity towards these different products determined by the proportion of the conformers of the initial protonated alcohols. These selectivities are explained by the DR processes being much faster than IR. These results are in direct contradiction with the dynamics simulations, which indicate a predominantly stepwise mechanism and selectivities that depend on the alkyl groups and dynamics effects. Indeed, despite the lifetimes of the secondary carbocations being short (<0.5 ps), IR can take place and thus provide a rich selectivity. These different selectivities, particularly for ET and I‐PR , are amenable to experimental observation and provide evidence for the minor role played by potential‐energy surface and the relevance of the dynamics effects (non‐IRC pathways, IR) in determining the reaction mechanisms and product distribution (selectivity).     

Synthese und Kristallstrukturen von [Cu4(As4Ph4)2(PRR′2)4], [Cu14(AsPh)6(SCN)2(PEt2Ph)8], [Cu14(AsPh)6Cl2(PRR′2)8], [Cu12(AsPh)6(PPh3)6], [Cu10(AsPh)4Cl2(PMe3)8], [Cu12(AsSiMe3)6(PRR′2)6] und [Cu8(AsSiMe3)4(PtBu3)4] (R,R′ = organische Gruppen)

Syntheses and Crystal Structures of [Cu₄(As₄Ph₄)₂(PRR′₂)₄], [Cu₁₄(AsPh)₆(SCN)₂(PEt₂Ph)₈], [Cu₁₄(AsPh)₆Cl₂(PRR′₂)₈], [Cu₁₂(AsPh)₆(PPh₃)₆], [Cu₁₀(AsPh)₄Cl₂(PMe₃)₈], [Cu₁₂(AsSiMe₃)₆(PRR′₂)₆], and [Cu₈(AsSiMe₃)₄(P^tBu₃)₄] (R, R′ = Organic Groups) Through the reaction of CuSCN with AsPh(SiMe₃)₂ in the presence of tertiary phosphines the compounds [Cu₄(As₄Ph₄)₂(PRR′₂)₄] ( 1 – 3 ) ( 1 : R = R′ = ⁿPr, 2 : R = R′ = Et; 3 : R = Me, R′ = ⁿPr) and [Cu₁₄(AsPh)₆(SCN)₂(PEt₂Ph)₈] ( 4 ) can be synthesised. Using CuCl instead of CuSCN results to the cluster complexes [Cu₁₄(AsPh)₆Cl₂(PRR′₂)₈] ( 5–6 ) ( 5 : R = R′ = Et; 6 : R = Me, R′ = ⁿPr), [Cu₁₂(AsPh)₆(PPh₃)₆] ( 7 ) and [Cu₁₀(AsPh)₄Cl₂(PMe₃)₈] ( 8 ). Through reactions of CuOAc with As(SiMe₃)₃ in the presence of tertiary phosphines the compounds [Cu₁₂(AsSiMe₃)₆(PRR′₂)₆] ( 9 – 11 ) ( 9 : R = R′ = Et; 10 : R = Ph, R′ = Et; 11 : R = Et, R′ = Ph) and [Cu₈(AsSiMe₃)₄(P^tBu₃)₄] ( 12 ) can be obtained. In each case the products were characterised by single‐crystal‐X‐ray‐structure‐analyses. As the main structure element 1 – 3 each have two As₄Ph₄^2–‐chains as ligands. In contrast 4 – 12 contain discrete AsR^2–ligands.     

Cleavage of the carbon-silicon bonds in trimethylsilylacetylenes by trans[(PR3)2PtX(R′OH)]PF6 cations and formation of cationic alkoxycarbene complexes of platinum(II)

Cationic alkoxycarbene complexes of platinum(II) have been isolated in the reactions of trans-[(PR₃)₂PtX(R′OH)]PF₆ (X  H or Me; R′  Me or Et) with Me₃SiCCR′′ (R′′  H, Me or SiMe₃). In these reactions cleavage of the carbon-silicon bond by the nucleophilic attack of alcohol has been observed. These carbene complexes have been characterized by elemental analyses and by IR, ¹H and ¹³C NMR spectral data. ¹³C NMR chemical shift data for carbene carbon atoms suggest that the carbene carbon may be very positively charged.     

Bi?Zn Bond Formation in Liquid Ammonia Solution: [Bi?Zn?Bi]4−, a Linear Polyanion that is Iso(valence)‐electronic to CO2

Reactions of the zinc(I) complex [Zn₂(Mesnacnac)₂] (Mesnacnac=[(2,4,6‐Me₃C₆H₂)NC(Me)]₂CH) with solid K₃Bi₂ dissolved in liquid ammonia yield crystals of the compound K₄[ZnBi₂]⋅(NH₃)₁₂ ( 1 ), which contains the molecular, linear heteroatomic [Bi Zn Bi]⁴⁻ polyanion ( 1 a ). This anion represents the first example of a three‐atomic molecular ion of metal atoms being iso(valence)‐electronic to CO₂ and being synthesized in solution. The analogy of the discrete [Bi Zn Bi]⁴⁻ anion and the polymeric [(ZnBi_4/2)⁴⁻] unit to monomeric CO₂ and polymeric SiS₂ is rationalized.     

Synthesis and Characterization of Pyrrolthiosemicarbazone Complexes of Palladium(II). Crystal Structures of [{Pd[C4H4NC(H)=NNC(S)NHMe](Cl)}2{μ‐Ph2P(CH2)3PPh2}] and [Pd{C4H4NC(H)=NNC(S)NHMe}{Ph2P(CH2)2PPh2‐P,P}](Cl)

Reaction of the thiosemicarbazone ligands C₄H₄NC(H)=NN(H)C(S)NHR (R = Me, a ; Et, b ) with Li₂[PdCl₄] gave the dinuclear complexes [Pd{C₄H₄NC(H)=NNC(S)NHR}(μ‐Cl)]₂ (R = Me, 1a ; Et, 1b ) with a central Pd₂Cl₂ core and with deprotonation of the thiosemicarbazones at the hydrazinic nitrogen atom. Treatment of 1a and 1b with triphenylphosphine gave the mononuclear compounds [Pd{C₄H₄C(H)=NNC(S)NHR}(Cl)(PPh₃)] (R = Me, 2a ; Et, 2b ), whereas reaction of 1a and 1b with tertiary diphosphines gave mono‐ and dinuclear compounds, as appropriate, with the corresponding diphosphine acting as a monodentate ( 6b ), chelating ( 3a ) and bridging ligand ( 4a, 5a , 4b, 5b ). Treatment of 1a and 1b with (Ph₂PCH₂CH₂PPh₂)W(CO)₅ gave the new heterobimetallic complexes 7a and 7b . The crystal structures of complexes 3a and 4a are described.     

Enol ethers and acetals: acylation with dichloroacetyl,acetyl and benzoyl chloride in ionic liquid medium

Synthesis of 4-alkoxy-1,1-dichloro-3-alken-2-ones [CHCl₂C(O)C(R²)C(R¹)-OR, where R, R¹, R² = Et, H, H; Me, Me, H; Et, H, Me; Me, –(CH₂)₂–; Me, –(CH₂)₃–; Et, Et, H; Et, Bu, H; Et, i-Pr, H; Et, i-Bu, H; Me, Ph, H; Me, thien-2-yl, H] from acylation of enol ethers and acetals with dichloroacetyl chloride, in ionic liquid ([BMIM][BF₄] or [BMIM][PF₆]) is reported. The synthesis of alkenones [R³–C(O)C(R²)C(R¹)-OR], where R/R¹/R²/R³ = Et/H/H/Ph, t-Bu/H/H/Ph, Me/-(CH₂)₄/Ph, Me/-(CH₂)₄/Me] from the reaction of enol ethers with benzoyl chloride or acetyl chloride, in ionic liquid [BMIM][BF₄], is also reported. Last products are described for the first time.     

A Route to Organyl(trialkoxysilyl)chalcogenides and Dichalcogenides, Bis(trialkoxysilylmethyl)chalcogenides and Dichalcogenides

Reactions of organylchalcogenomagnesium halides RYMgX (in situ) (R = Me, Et, Ph; Y = S, Se, Te; X = Br, I) with (halomethyl)trialkoxysilanes X'CH₂Si(OR')3 (X' = Cl, I; R' = Me, Et) at reflux in tetrahydrofuran and the systems of tetrahydrofuran-acetonitrile 1:2, and ether-acetonitrile 1:2 are studied. These reactions are shown to lead to formation of mixtures of corresponding organyl(trialkoxysilylmethyl)chalcogenide and -dichalcogenide, bis(trialkoxysilyl methyl)chalcogenide and -dichalcogenide, as well as the contaminants 2,2,6,6-tetraalkoxy-2,6-disila-4-chalcogen-1-oxane, diorganylchalcogenide and -dichalcogenide, and other organic and organosilicon compounds. Composition of the formed mixtures debends considerably on the structure of R, nature of the chalcogen Y (S, Se, Te), and halides X and X' in the initial reagents, and reaction conditions. The most of synthesized and isolated organosilicon chalcogenides are newly obtained compounds.     

Synthese und Kristallstrukturen der Wolfram(VI)-Alkin-Komplexe [W2(O)(OMe)6(Et?Se?CC?Se?Et)2] und Li[W(OMe)5(Et?Te?CC?Te?Et)]

Synthesis and Crystal Structures of the Tungsten(VI)-alkyne Complexes [W₂(O)(OMe)₆(Et? Se? C?C? Se? Et)₂] and Li[W(OMe)₅(Et? Te? C?C? Te? Et)] The title compounds have been prepared by reactions of lithium methanolate with [WCl₄(Et? Se? C?C? Se? Et)(THF)] and [WCl₄(Et? Te? C?C? Te? Et)(THF)], respectively, in diethylether suspensions. Both complexes were characterized by crystal structure determinations. [W₂(O)(OMe)₆(Et? Se? C?C? Se? Et)₂]: Space group P1 , Z = 2, structure determination with 4 320 observed unique reflections, R = 0.041. Lattice dimensions at ?70°C: a = 949.3, b = 1 225.3, c = 1 285.0 pm, α = 82.48°; γ = 82.44°; β = 81.44°. The tungsten atoms are bridged by three μ₂-O-atoms of the OMe groups; the alkyne ligands are coordinated side-on in a metallacyclopropene-like fashion. Li[W(OMe)₅(Et? Te? C?C? Te? Et)]: Space group P1 , Z = 2, structure determination with 9 381 observed unique reflections, R = 0.038. Lattice dimensions at ?70°C: a = 983.4, b = 1606.9, c = 1971.5 pm, α = 66.09°, β = 84.29°, γ = 79.83°. The lithium ions link the [W(OMe)₅(Et? Te? C?C? Te? Et)]^? anions to a trimeric ion ensemble via the O atoms of three OMe groups of each anion.     

(2‐Hydroxy­ethyl)­hydrazinium(2+) dichloride

The crystal structure of the title compound, C₂H₁₀N₂O²⁺·2Cl⁻, is built up from one 2‐hydroxy­ethyl­hydrazinium(2+) cation and two Cl⁻ anions. The mol­ecular structure is stabilized by O—H⋯Cl and N—H⋯Cl hydrogen bonds. The crystal structure is stabilized by one N—H⋯O and three N—H⋯Cl inter­actions, and the three‐dimensional network of hydrogen bonds stabilizes the crystal packing. All five hydrazinium H atoms are involved in hydrogen bonds to Cl⁻ anions. The Cl⋯H contact distances range from 2.122 (15) to 2.809 (14) Å.     

Zur Reaktivität des Ferriophosphaalkens (Z)‐[Cp*(CO)2FeP=C(tBu)NMe2] gegenüber Propiolsäureestern HC≡C‐CO2R (R=Me,Et) und Acetylendicarbonsäureestern RO2C‐C≡C‐CO2R (R=Me,Et, tBu)

On the Reactivity of the Ferriophosphaalkene (Z)‐[Cp*(CO)₂Fe‐P=C(tBu)NMe₂] towards Propiolates HC≡C‐CO₂R (R=Me, Et) and Acetylene Dicarboxylates RO ₂C‐C≡C‐CO₂R (R=Me, Et, tBu) The reaction of equimolar amounts of (Z)‐[Cp*(CO)₂Fe‐P=C(tBu)NMe₂] 3 and methyl‐ and ethyl‐propiolate ( 2a, b ) or of 3 and dialkyl acetylene dicarboxylates 1a (R=Me), 1b (Et), 1c (tBu) afforded the five‐membered metallaheterocycles [Cp*(CO) =C(tBu)NMe₂] ( 4a, b ) and [Cp*(CO) =C(tBu)NMe₂] ( 5a—c ). The molecular structures of 4b and 5a were elucidated by single crystal X‐ray analyses. Moreover, the reactivity of 4b towards ethereal HBF₄ was investigated.     

Zur Reaktion von Metall-koordinierten Kohlenmonoxid mit Yliden XXII. Bis(diphenylphosphino)methanid-Eisen-Komplexe Cp(L)Fe(Ph2PCHPPh2) (L = CO,Me3P)

The reaction of [Cp(CO)(dppm)Fe]BF₄ (1a) with the phosphorus ylide Me₃PCH₂ yields the novel bis(phosphino)methanideiron complex Cp(CO)Fe(Ph₂PCHPPh₂) (2), which upon photolysis in the presnece of Me₃P is converted into Cp(Me₃P)Fe(Ph₂PCHPPh₂ (3). Reaction of 2 with MeOSO₂CF₃ gives a mixture of the iron salts [(Cp(CO)Fe(Ph₂PCR(R′)PPh₂)]CF₃SO₃ (R = R′ = H (1b), R = R′ = Me (6) and R = H, R′ = Me (syn/anti-4)).     

The crystal structure,equilibrium and spectroscopic studies of bis(dialkyldithiocarbamate) copper(II) complexes [Cu2(R2dtc)4] (dtc=dithiocarbamate)

Four copper(II) complexes of bis(dialkyldithiocarbamate) [Cd(R₂dtc)₂] (R=Me, Et, Pr, i-Pr; dtc=dithiocarbamate) have been prepared and characterized by elemental analysis, IR and ESR spectra studies. Their equilibrium constants (K), determined by a UV–vis spectrometry in EtOH, were influenced by the alkyl groups in the following order: i-Pr>n-Pr≈Et>Me. The single crystal structures of complex [Cu₂(R₂dtc)₄] have been determined using X-ray diffraction methods. The compounds [Cu₂(Et₂dtc)₄] and [Cu₂(Pr₂dtc)₄] are built of centrosymmetric neutral dimeric [Cu₂(R₂dtc)₄] entities. The copper atom lies in a distorted square–pyramidal environment. The four equatorial donors are two bidentate chelate sulfur atoms from two dtc ligands. One of the sulfur atoms from the third dtc ligand acts as a bridging ligand occupying the apical position of the symmetry-related copper atom in the dimer structure, which is viewed as two edge-sharing distorted square–pyramids. The structure of [Cu₂(i-Pr₂dtc)₄] is square planar with an exactly planar CuS₄ unit and nearly planar NCS₂ moieties. The Cu–S distances shows small decreases along the series n-Pr>Et>i-Pr, the biggest change being for the diisopropyl complex. The alkyl substituents at the nitrogen atom affect their coordination number and Cu⋯Cu distance. In the solid, [Cu₂(n-Pr₂dtc)₄] has the shortest Cu⋯Cu distance and [Cu(i-Pr₂dtc)₂] has the longest one.     

trans‐Di­aqua­bis­(thio­semicarb­azido‐κ2N,S)­nickel(II) dimaleate dihydrate

In the title compound, [Ni(CH₅N₃S)₂(H₂O)₂](C₄H₃O₄)₂·2H₂O, the Ni atom lies on a center of symmetry and is coordinated by N and S atoms from two thio­semicarbazide ligands and the O atoms of two water mol­ecules in a distorted octahedral geometry. In the asymmetric unit, the three components are linked together by one O—H⋯O and two N—H⋯O hydrogen bonds. The packing is built from molecular ribbons parallel to the b direction, stabilized by intramolecular hydrogen bonds, and by one N—H⋯S and two N—H⋯O intermolecular hydrogen bonds. The ribbons are further connected into columns by N—H⋯O interactions and then into a three‐dimensional network by three O—H⋯O hydrogen bonds.