Functionalized organotin-chalcogenide complexes that exhibit defect heterocubane scaffolds: formation, synthesis, and characterization

Introducing Distinct Structural and Optical Properties into Organotin Sulfide Clusters by the Attachment of Perylenyl and Corannulenyl Groups

We report the introduction of distinct optical properties into organotin sulfide clusters by the attachment of extended polycyclic aromatic organic molecules. This was realized by the reactions of [(R^NSn)₄S₆] (R^N = CMe₂CH₂CMeNNH₂) with 3-perylenecarbaldehyde and corannulenecarbaldehyde, respectively. The reaction with the first reactant leads to the formation of two products [(R^perylSn)₃S₄][SnCl₃] [1a; R^peryl = CMe₂CH₂CMeNNCH(C₂₀H₁₁)] and [(R^perylSn)₃S₄Cl] (1b). Structural differences between these two compounds are reflected in their different optical absorption and luminescence behavior, yet in both cases, the main emission is red-shifted relative to 3-perylenecarbaldehyde. The second organic molecule affords the compound [(R^corSn)₄Sn₂S₁₀] [2; R^cor = CMe₂CH₂CMeNNCH(C₂₀H₉)] with intriguing optical properties, including a broad emission with essentially no shift in λ_max compared to corannulenecarbaldehyde. All compounds were obtained as single crystals, and their structures were determined by means of single-crystal X-ray diffraction. The optical properties of the highly luminescent compounds were investigated by means of emission and time-resolved photoluminescence spectroscopy measurements.

Systematic Access of Ternary Organotetrel-Copper Chalcogenide Clusters by [PhTE3 ]3- Anions (T=Si, Sn; E=S, Se)

Fragmentation reactions of organotetrel chalcogenide heteroadamantane-type clusters [(PhT)4 E6 ] (T/E=Si/S (1); Si/Se; Sn/S, and Sn/Se) by addition of the corresponding sodium chalcogenide gave salts of the general formula Na3 [PhTE3 ], with T/E=Si/S (2); Si/Se (3); Sn/S (A); Sn/Se (4). Reaction of these salts with [Cu(PPh3 )3 Cl] gave a series of organotetrel-copper chalcogenide clusters [(CuPPh3 )6 (PhTE3 )2 ] with T/E=Si/S; (5), Si/Se (6), Sn/S (7) and Sn/Se (8). Compounds 5-8 share a common structural motif with two intact {PhTE3 } units coordinating a Cu6 moiety, which was previously reported with other ligands, and for the Sn and Ge congeners only. If the Sn/Se reaction system was allowed to crystallize more slowly, single crystals of compound [(CuPPh3 )6 (PhSnSe3 )3 Cu3 SnSe] (9) were obtained, which are based on a larger cluster structure. Hence, 9 might form from 8 through incorporation of additional cluster fragments. The experimentally and quantum chemically determined optical properties were compared to related clusters.

Pyrene-Terminated Tin Sulfide Clusters: Optical Properties and Deposition on a Metal Surface

Herein, we present the synthesis of two pyrene-functionalized clusters, [(Rpyr Sn)4 S6 ]⋅2 CH2 Cl2 (4) and [(Rpyr Sn)4 Sn2 S10 ]⋅n CH2 Cl2 (n=4, 5 a; n=2, 5 b; Rpyr =CMe2 CH2 C(Me)N-NC(H)C16 H9 ), both of which form in reactions of the organotin sulfide cluster [(RN Sn)4 S6 ] (C; RN =CMe2 CH2 C(Me)N-NH2 ) with the well-known fluorescent dye 1-pyrenecarboxaldehyde (B). In contrast, reactions using an organotin sulfide cluster with another core structure, [(RN Sn)3 S4 Cl] (A), leads to formation of small molecular fragments, [(Rpyr Cl2 Sn)2 S] (1), (pyren-1-ylmethylene)hydrazine (2), and 1,2-bis(pyren-1-ylmethylene)hydrazine (3). Besides synthesis and structures of the new compounds, we report the influence of the inorganic core on the optical properties of the dye, which was analyzed exemplarily for compound 5 a via absorption and fluorescence spectroscopy. This cluster was also used for exploring the potential of such non-volatile clusters for deposition on a metal surface under vacuum conditions.

MeSi(CH2 SnRO)3 (R=Ph, Me3 SiCH2 ): Building Blocks for Triangular-Shaped Diorganotin Oxide Macrocycles

The syntheses of the novel silicon-bridged tris(tetraorganotin) compounds MeSi(CH2 SnPh2 R)3 (2, R=Ph; 5, R=Me3 SiCH2 ) and their halogen-substituted derivatives MeSi(CH2 SnPh(3-n) In )3 (3, n=1; 4, n=2) and MeSi(CH2 SnI2 R)3 (6, R=Me3 SiCH2 ) are reported. The reaction of compound 4 with di-t-butyltin oxide (t-Bu2 SnO)3 gives the oktokaideka-nuclear (18-nuclear) molecular diorganotin oxide [MeSi(CH2 SnPhO)3 ]6 (7) while the reaction of 6 with sodium hydroxide, NaOH, provides the trikonta-nuclear (30-nuclear) molecular diorganotin oxide [MeSi(CH2 SnRO)3 ]10 (8, R=Me3 SiCH2 ). Both 7 and 8 show belt-like ladder-type macrocyclic structures and are by far the biggest molecular diorganotin oxides reported to date. The compounds have been characterized by elemental analyses, electrospray mass spectrometry (ESI-MS), NMR spectroscopy, 1 H DOSY NMR spectroscopy (7), IR spectroscopy (7, 8), and single-crystal X-ray diffraction analysis (2, 7, 8).

Trapping of ZnCl2 by bipyridyl-functionalized organotin sulfide clusters, and its effect on optical properties

We report the syntheses of two new organotin sulfide clusters with heteroaromatic substituents. A phenanthroline-functionalized tin sulfide cluster [(RPhenSn)4S6] (1; RPhen = CMe2CH2C(Me)N-NC(H)C12H7N2) and a bipyridyl-terminated cluster [(R4-bipySn)4S6] (2; R4-bipy = CMe2CH2C(Me)N-NC(H)-4-C10H7N2) were obtained from reactions of the hydrazone-functionalized organotin sulfide cluster [(RNSn)4S6] (RN = CMe2CH2C(Me)N-NH2) with 1,10-phenanthroline-5-carboxaldehyde or 2,2'-bipyridine-4-carbaldehyde. 1 and 2 were tested towards their capability of trapping metal ions by means of the terminal chelating ligands. The reaction of 2 with ZnCl2 afforded the cluster compound [(R4-bipyZnCl2Sn)4S6] (5), in which four ZnCl2 units are coordinated by the heteroaromatic organic groups. We discuss the structures and demonstrate the effect of ZnCl2 trapping on optical absorption and luminescence properties.

Current advances in tin cluster chemistry

This perspective summarizes highlights and most recent advances in tin cluster chemistry, thereby addressing the whole diversity of (mostly) discrete units containing tin atoms. Although being a (semi-)metallic element, tin is in the position to occur both in formally positive or negative oxidation states in these molecules, which causes a broad range of fundamentally different properties of the corresponding compounds. Tin(iv) compounds are not as oxophilic and not as prone to hydrolysis as related Si or Ge compounds, hence allowing for easier handling and potential application. Nevertheless, their reactivity is high due to an overall reduction of bond energies, which makes tin clusters interesting candidates for functional compounds. Beside aspects that point towards bioactivity or even medical applications, materials composed of naked or ligand-protected tin clusters, with or without bridging ligands, show interesting optical, and ion/molecule-trapping properties.

Controlling the White-Light Generation of [(RSn)4 E6 ]: Effects of Substituent and Chalcogenide Variation

Adamantane-type organotin chalcogenide clusters of the general composition [(RT)4 S6 ] (R=aromatic substituent, T=Si, Ge, Sn) have extreme non-linear optical properties that lead to highly directional white-light generation (WLG) upon irradiation with an IR laser diode. However, the mechanism is not yet understood. Now, a series of compounds [(RSn)4 E6 ] (R=phenyl, cyclopentadienyl, cyclohexyl, benzyl, CH2 CH2 (C6 H4 )CO2 Et; E=S, Se), were prepared, characterized, and investigated for their nonlinear optical properties. With the exception of crystalline [(BnSn)4 S6 ], all these compounds exhibit WLG with similar emission spectra; slight blue-shifts are observed by introduction of cyclopentadienyl substituents, while the introduction of Se in the inorganic core can provoke a red-shift. These investigations disprove the initial assumption of an aromatic substituent being a necessary precondition; the precondition seems to be the presence of (cyclic) substituents providing enough electron density.

[{(PhSn)3SnS6}{(MCp)3S4}] (M = W, Mo): Minimal Molecular Models of the Covalent Attachment of Metal Chalcogenide Clusters on Doped Transition Metal Dichalcogenide Layers

With the aim to mimic the yet unknown covalent deposition of metal chalcogenide clusters on transition metal dichalcogenide (TMDC) MoS₂ or WS₂ layers, and thereby explore the interaction between the two systems and potential consequences on physical properties of the TMDC material, we synthesized heterobimetallic model systems. The heterocubane-type cluster [(SnCl₃)(WCp)₃S₄] (1), the organotin-sulfidomolybdate cluster [{(PhSn)₃SnS₆}{(MoCp)₃S₄}] (2), and the corresponding tungstate [(PhSn)₃SnS₆{(WCp)₃S₄}] (3) were obtained in ligand exchange reactions from [(PhSn)₄S₆] and [M(CO)₃CpCl]. Indeed, the {M₃S₄} cages in 1-3 resemble a section of the respective TMDC monolayers, altogether representing minimal molecular model systems for the adsorption of organotin sulfide clusters on MoS₂ or WS₂. The interaction between the {(MCp)₃S₄} and {(PhSn)₃SnS₆} subunits is characterized by multicenter bonding, rendering the respective Sn atom as Sn(II), hence driving the clusters into a mixed-valence Sn(IV)/Sn(II) situation, and the M atoms as M(IV) upon an in situ redox process. The attachment is thus weaker than via regular covalent M-S bonds, but definitely stronger than via van der Waals interactions that have been characteristic for all known interactions of clusters on TMDC surfaces so far. Computational analyses of an extended model mimicking the electronic situation in the cluster prove the analogy to a covalent attachment on TMDCs.

Dinuclear organogermanium chalcogenide complexes as intermediates towards functionalized clusters

Reactions of R1GeCl3 (R1 = CMe2CH2COMe) with (Me3Si)2E (E = S, Se, Te) yield three new organogermanium chalcogenide complexes [(R1GeCl)2S2] (1), [(R1GeCl)2Se2] (2), and [(R1GeCl)2Te2] (3) with functionalized ligands R1 = CMe2CH2COMe. NMR titration experiments clearly demonstrate that these dimeric complexes are intermediates in the formation of the well-known sesquichalcogenide clusters [(R1Ge)4E6]. In striking contrast to related tin compounds that were recently reported, the mono-bridged complexes of the type "[(R1GeCl2)2E]" and defect-heterocubane-type clusters "[(R1Ge)3E4Cl]" do not form on the NMR time scale for E = S or Te, and only in traces for E = Se.

Organotin Selenide Clusters and Hybrid Capsules

Several compounds with unique structural motifs that have already been known from organotin sulfide chemistry, but remained unprecedented in organotin selenide chemistry so far, have been synthesized. The reaction of [(R¹ Sn)₄ Se₆ ] (R¹ =CMe₂ CH₂ C(O)Me) with N₂ H₄ ⋅H₂ O/(SiMe₃ )₂ Se and PhN₂ H₃ /(SiMe₃ )₂ Se led to the formation of [{(R² Sn)₂ SnSe₄ }₂ (μ-Se)₂ ] (1; R² =CMe₂ CH₂ C(Me)NNH₂ ) and [{(R³ Sn)₂ SnSe₄ }₂ (μ-Se)₂ ] (2; R³ =CMe₂ CH₂ C(Me)NNPhH)). The addition of ortho-phthalaldehyde to [(R² Sn)₄ Se₆ ] yielded a cluster with intramolecular bridging of the organic groups, namely, [(R⁴ Sn₂ )₂ Se₆ ] (3; R⁴ =(CMe₂ CH₂ C(Me)NNCH)₂ C₆ H₄ ). The introduction of organic ligands with longer chains finally allowed the isolation of inorganic-organic capsules of the type [(μ-R)₃ (Sn₃ Se₄ )₂ ]X₂ , with R=(CMe₂ CH₂ C(Me)NNHC(O))₂ (CH₂ )₄ and X=[SnC₃ ], Cl (4 a, b) or R=CMe₂ CH₂ C(Me)NNH)₂ and X=[SnCl₃ ] (5). The capsules enclose solvent molecules and/or anions as guests. All compounds were characterized by means of single-crystal X-ray diffraction studies, NMR spectroscopy, and mass spectrometry.

Ternary Mixed-Valence Organotin Copper Selenide Clusters

Reactions of the organotin selenide chloride clusters [(R¹ Sn^IV )₃ Se₄ Cl] (A, R¹ =CMe₂ CH₂ C(O)Me) or [(R¹ Sn^IV )₄ Se₆ ] (B) with [Cu(PPh₃ )_3-x Cl_x ] yield cluster compounds with different inorganic, mixed-valence core structures: [Cu₄ Sn^II Sn^IV₆ Se₁₂ ], [Cu₂ Sn^II₂ Sn^IV₄ Se₈ Cl₂ ], [Cu₂ Sn^II Sn^IV₄ Se₈ ], [Cu₂ Sn^II₂ Sn^IV₂ Se₄ Cl₄ ], and [Cu₂ Sn^IV₂ Se₄ ]. Five of the compounds, namely [(CuPPh₃ )₂ {(R¹ Sn^IV )₂ Se₄ }] (1), [(CuPPh₃ )₂ Sn^II {(R² Sn^IV )₂ Se₄ }₂ ] (2), [(CuPPh₃ )₂ (Sn^II Cl)₂ {(RSn^IV )₂ Se₄ }₂ ] (3) [(CuPPh₃ )₂ (Sn^II Cu₂ ){(R¹ Sn^IV )₂ Se₄ }₃ ] (4), and [Cu(CuPPh₃ )(Sn^II Cu₂ ){(R¹ Sn^IV )₂ Se₄ }₃ ] (5) are structurally closely related. They are based on [(CuPPh₃ )₂ {(RSn^IV )₂ Se₄ }_n ] aggregates comprising [(RSn^IV )₂ Se₄ ] and [CuPPh₃ ] building units, which are linked by further metal atoms. A sixth compound, [(CuPPh₃ )₂ (Sn^II Cl)₂ {(R¹ Sn^IV Cl)Se₂ }₂ ] (6), differs from the others by containing [(RSn^IV Cl)Se₂ ] units instead, which affects the absorption properties. The compounds were analyzed by single-crystal X-ray diffraction, NMR and ¹¹⁹ Sn Mössbauer spectroscopy, DFT calculations as well as optical absorption experiments.

Syntheses, structures and anti-tumor activity of four organotin(iv) dicarboxylates based on (1,3,4-thiadiazole-2,5-diyldithio)diacetic acid

Four novel organotin complexes, derived from flexible (1,3,4-thiadiazole-2,5-diyldithio)diacetic acid (H₂tzda), have been synthesized and characterized by elemental analysis, FT-IR, NMR and X-ray crystallography.

Formation and Structural Diversity of Organo-Functionalized Tin-Silver Selenide Clusters

When reacting the organic functionalized tin selenide clusters [(SnR¹ )₃ Se₄ Cl] (A, R¹ =CMe₂ CH₂ C(O)Me) or [(SnR¹ )₄ Se₆ ] (B) with (SiMe₃ )₂ Se and [Ag(PPh₃ )₃ Cl] at -78 °C in CH₂ Cl₂ , a microcrystalline intermediate (compound 1) precipitates, which was investigated by magic angle spinning (MAS) NMR spectroscopy, powder X-ray diffraction (PXRD), energy dispersive X-ray (EDX) spectroscopy, and quantum chemistry calculations, to derive information about its composition and structure. Compound 1 re-dissolves under reorganization into the organo-functionalized Ag/Sn/Se cluster compound [Ag₆ (μ₆ -Se)(Ag₈ Se₁₂ ){(R¹ Sn)₂ Se₂ }₆ ] (2), or the mixed-valence cluster [(AgPPh₃ )₂ (Sn^II Cl)₂ Se₂ {(R¹ Sn^IV )₂ Se₂ }₂ ] (3), depending on the presence or the exclusion of daylight, respectively. The addition of N₂ H₄ ⋅H₂ O to a solution of 1 yields selectively [Ag₇ (μ₇ -Se)(Ag₇ Se₁₂ ){(R² Sn)₂ Se₂ }₆ ] (4, R² =CMe₂ CH₂ C(N₂ H₂ )Me), the Ag/Sn/Se core of which is isomeric to that of 2. 2-4 were characterized by X-ray diffraction. NMR spectroscopic studies on solutions of 1 indicate the co-existence of different species.

Tin sulfide and selenide clusters soluble in organic solvents with the core structures of Sn4S6 and Sn4Se6

Reactions of LSnCl (1) (L = N(2,6-iPr2C6H3)(SiMe3)) with sulfur and selenium, respectively under mild conditions yielded two tin chalcogenide clusters. Surprisingly the tin atoms of the L4Sn4S6 (2) and L4Sn4Se6 (3) clusters are oxidized from Sn(II) of the precursor to Sn(IV) of the products under concomitant reduction of elemental sulfur and selenium to sulfide and selenide, respectively. The released chlorine radicals from the precursor LSnCl (1) react under oxidative addition with another LSnCl molecule to yield the side product LSnCl3 (4). The soluble nature of clusters 2 and 3 in organic solvents is a unique property of this class of compounds and makes them suitable for reactions in organic solvents. Compounds 2 and 3 were characterized by single crystal X-ray diffraction and multinuclear NMR investigations. Furthermore in ROP polymerization, the two products show high catalytic activity. For the first time a tin selenide compound functions in ROP catalysis.

Formation and Reactivity of Organo-Functionalized Tin Selenide Clusters

Reactions of R(1) SnCl3 (R(1) =CMe2 CH2 C(O)Me) with (SiMe3 )2 Se yield a series of organo-functionalized tin selenide clusters, [(SnR(1) )2 SeCl4 ] (1), [(SnR(1) )2 Se2 Cl2 ] (2), [(SnR(1) )3 Se4 Cl] (3), and [(SnR(1) )4 Se6 ] (4), depending on the solvent and ratio of the reactants used. NMR experiments clearly suggest a stepwise formation of 1 through 4 by subsequent condensation steps with the concomitant release of Me3 SiCl. Furthermore, addition of hydrazines to the keto-functionalized clusters leads to the formation of hydrazone derivatives, [(Sn2 (μ-R(3) )(μ-Se)Cl4 ] (5, R(3) =[CMe2 CH2 CMe(NH)]2 ), [(SnR(2) )3 Se4 Cl] (6, R(2) =CMe2 CH2 C(NNH2 )Me), [(SnR(4) )3 Se4 ][SnCl3 ] (7, R(4) =CMe2 CH2 C(NNHPh)Me), [(SnR(2) )4 Se6 ] (8), and [(SnR(4) )4 Se6 ] (9). Upon treatment of 4 with [Cu(PPh3 )3 Cl] and excess (SiMe3 )2 Se, the cluster fragments to form [(R(1) Sn)2 Se2 (CuPPh3 )2 Se2 ] (10), the first discrete Sn/Se/Cu cluster compound reported in the literature. The derivatization reactions indicate fundamental differences between organotin sulfide and organotin selenide chemistry.

{[Ir3(cod)3(μ3-S)2](μ3-S)SnCl}2 – a ternary Ir–Sn–S cluster with the iridium atoms in three different chemical environments

The cluster {[Ir₃(cod)₃(μ₃-S)₂](μ₃-S)SnCl}₂ with an unprecedented topology of Sn, Ir, and S atoms was obtained by reactions of organo-functionalized tinsulfide clusters with [IrCl(cod)]₂.

Syntheses, structures and anti-tumor activity of four new organotin(iv) carboxylates based on 2-thienylselenoacetic acid

With the 2-thienylselenoacetic acid ligand, four new organotin complexes have been synthesized and characterized by X-ray crystallography, elemental analysis, FT-IR and NMR (¹H,¹³C, and¹¹⁹Sn) spectroscopy.

Synthesis and Thorough Investigation of Discrete Organotin Telluride Clusters

Systematic experimental and theoretical investigations of reactions of R(1)SnCl3 (R(1) = CMe2CH2C(Me)O) with (Me3Si)2Te allowed for the stepwise formation and single-crystalline isolation of the first tin sesquitelluride clusters with functional organic ligands. Subsequent derivatization of the latter took place under reorganization of the inorganic core, affording clusters with complex hybrid architectures.

Bronze, silver and gold: functionalized group 11 organotin sulfide clusters

The synthesis, properties and reactivity of group 11 organotin sulfide clusters [(R(1)Sn)4(SnCl)2(MPPh3)2S8] (M = Cu, Ag), [(R(3)Sn)10Ag10S20], and [(R(1,3)Sn)2(AuPPh3)2S4] with covalently bound, carbonyl or hydrazine-terminated ligands R(1) = CMe2CH2C(Me)O or R(3) = CMe2CH2C(Me)NNH2 are reported.

Revisiting [(RSn(IV))6Sn(III)2S12]: directed synthesis, crystal transformation, and luminescence properties

We report the synthesis of the mixed-valence cluster [(R(5)Sn(IV))6Sn(III)2S12] [1; R(5) = CMe2CH2C(O)Me] under optimization of the reaction conditions. A new crystalline form of 1 in the orthorhombic space group Pbca was found at 250 K, which undergoes crystal transformation into the known monoclinic one at lower temperature. Further, we have studied the luminescence properties of 1. Time-resolved photoluminescence measurements confirm the lability of the tin-chalcogenide bonds to UV irradiation, while the organic ligands are much less affected by it.

Synthesis, crystal structure, and photoluminescence studies of a ruthenocenyl-decorated Sn/S cluster

Recently, we reported on ferrocenyl-decorated Sn/S clusters; herein, we present the extension of our investigations by attachment of ruthenocenyl units to an according cluster skeleton. The latter was realized upon improvement of the synthesis of acetylruthenocene, its conversion to a hydrazone derivative, and the subsequent reaction with a keto-functionalized Sn/S precursor complex. The report comprises the crystal structures of acetylruthenocene and the ruthenocenyl-terminated Sn/S cluster [(R(Rc)Sn)4Sn2S10] (R(Rc) = CMe2CH2C(Me)═N-N═C(Me)Rc), as well as the discussion of the electrochemical properties of the latter and its behavior during time-resolved photoluminescence investigations.