Towards the installation of transition metal ions on donor ligand decorated tin sulfide clusters

Carboxylic Acid-Assisted Synthesis of Tin(II) Iodide: Key for Stable Large-Area Lead-Free Perovskite Solar Cells

Despite significant progress in tin-based perovskites, the development of stable and high-performance tin-based perovskite solar cells (TPSCs) remains a challenge. In this pursuit, a multitude of strategies have been explored, encompassing the use of reducing agents, antioxidants, bulky cations, and customized solvent systems. We propose an improved approach for synthesizing SnI2 from elemental tin and iodine. Here, we generate tin nanoparticles grafted with a carboxylic acid in situ from tin powder-carboxylic acid-assisted synthesis (CAAS). This methodology not only improves the synthesis process of SnI2 but also enhances precursor stability against oxidation. We use 119Sn MAS NMR to study the atomic-level structure of the resulting FASnI3 thin films and find that the CAAS approach leads to highly pure and unoxidized material. We report remarkable reproducibility in fabricating large-area (1 cm2) flexible TPSCs with significant improvement in open-circuit voltage leading to the champion device showing a power conversion efficiency of 8.35%.

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.

Selective replacement of organosilicon units in the cluster [(PhSi)4S6] with coinage metal complex fragments

Adamantane-type organo-group 14 chalcogenide clusters were shown to possess extreme non-linear optical properties. Reactivity studies of corresponding organosilicon sulfide clusters towards copper and silver complexes indicate a replacement of exactly one of the organosilicon groups with a metal complex fragment to form [(Et₃PAg)₃(PhSi)₃S₆] (1) and [Na₂(thf)_2.33][(Me₃PCu)(PhSi)₃S₆] (2)-in striking contrast to reactions of organotin chalcogenide clusters, which are more significantly and less systematically re-organized. The silicon compounds are thus more suited for controlled modifications of their geometric and electronic structures.

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.

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.

Variations in the Interplay of Intermetallic and Metal Chalcogenide Units in Organotin-Copper Selenide Clusters

We report the formation and structures of two new organotin-copper selenide clusters that were obtained in a two-step procedure. First, [(R¹Sn)₄Se₆] [R¹ = CMe₂CH₂C(O)Me] is reacted with [Cu(PPh₃)₃Cl] and (SiMe₃)₂Se to form a bright-orange powder, the nature of which could not be identified in detail, yet a suspension of it in CH₂Cl₂ reacts with N₂H₄·H₂O to afford single crystals of two cluster compounds, either [(Cu₃Sn){(R²Sn)₂Se₄}₂{(R²Sn₂)Se₃}] (1) or [(N₂H₄)(Cu₄Sn){(R²Sn)₂Se₄}₃] [2; R² = CMe₂CH₂C(NNH₂)Me]. Both are based on an intermetallic Cu_xSn cluster core (x = 3, 4), which is surrounded by organotin selenide units in different fashions. The results foster the assumption of a complex equilibrium to be present in according reaction mixtures.

[SnS4]4- clusters modified MgAl-LDH composites for mercury ions removal from acid wastewater

The high acidity of mercury ions (Hg²⁺) contained wastewater can complicate its safe disposal. MgAl-LDHs supported [SnS₄]^4- clusters were synthesized for Hg²⁺ removal from acid wastewater. The active sites of [SnS₄]^4- clusters were inserted into the interlayers of MgAl-LDHs using an ion-exchange method. The experimental results indicated that [SnS₄]^4-/MgAl-LDHs composite can obtain higher than 99% Hg²⁺ removal efficiency under low pH values. The maximum mercury adsorption capacity is 360.6 mg g^-1. It indicated that [SnS₄]^4- clusters were the primary active sites for mercury uptake, existing as stable Hg₂(SnS₄) on the surface of the composite. Under low pH values, such a composite seems like a "net" for HgSO₄ molecules, exhibiting great potential for mercury removal from acid solutions. Moreover, the co-exist metal ions such as Zn²⁺, Na⁺, Cd²⁺, Cr³⁺, Pb²⁺, Co²⁺, and Ni²⁺ have no significant influences on Hg²⁺ removal. The adsorption isotherms and kinetics were also studied, indicating that the adsorption mechanism follows a monolayer chemical adsorption model. The [SnS₄]^4-/MgAl-LDHs composite exhibits a great potential for Hg²⁺ removal from acid wastewater.

Mono- and Hexanuclear Zinc Halide Complexes with Soft Thiopyridazine Based Scorpionate Ligands

Scorpionate ligands with three soft sulfur donor sites have become very important in coordination chemistry. Despite its ability to form highly electrophilic species, electron-deficient thiopyridazines have rarely been used, whereas the chemistry of electron-rich thioheterocycles has been explored rather intensively. Here, the unusual chemical behavior of a thiopyridazine (6-tert-butylpyridazine-3-thione, HtBuPn) based scorpionate ligand towards zinc is reported. Thus, the reaction of zinc halides with tris(6-tert-butyl-3-thiopyridazinyl)borate Na[TntBu] leads to the formation of discrete torus-shaped hexameric zinc complexes [TntBuZnX]6 (X = Br, I) with uncommonly long zinc halide bonds. In contrast, reaction of the sterically more demanding ligand K[TnMe,tBu] leads to decomposition, forming Zn(HPnMe,tBu)2X2 (X = Br, I). The latter can be prepared independently by reaction of the respective zinc halides and two equiv of HPnMe,tBu. The bromide compound was used as precursor which further reacts with K[TnMe,tBu] forming the mononuclear complex [TnMe,tBu]ZnBr(HPnMe,tBu). The molecular structures of all compounds were elucidated by single-crystal X-ray diffraction analysis. Characterization in solution was performed by means of 1H, 13C and DOSY NMR spectroscopy which revealed the hexameric constitution of [TntBuZnBr]6 to be predominant. In contrast, [TnMe,tBu]ZnBr(HPnMe,tBu) was found to be dynamic in solution.

4,5-Diazafluorene N-glycopyranosyl hydrazones as scaffolds for potential bioactive metallo-organic compounds: Synthesis, structural study and cytotoxic activity

A series of novel N¹-(4,5-diazafluoren-9-yliden)-N²-glycopyranosyl hydrazines was prepared in synthetically useful yields by treatment of 9H-4,5-diazafluoren-9-hydrazone with different unprotected monosaccharides. The reactions with the monosaccharides tested afforded stereoselectively, and exclusively, cyclic derivatives, whose structures correspond to N-β-glycopyranosyl hydrazones except for the d-arabinose derivative that agrees with the α-anomer. Several copper(II) complexes having a 2:1 ligand to metal mole ratio were also prepared. The metal complexes can bind DNA sequences and preferentially stabilize G-quadruplex DNA structures over dsDNA. The fucose, rhamnose and deoxyglucose copper(II) complexes exhibited a cytotoxic activity against cultured HeLa and PC3 tumor cells comparable to other metal complexes normally used for chemotherapeutic purposes, such as cisplatin.

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.

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.

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.

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.