Functionalization of Sn/S Clusters with Hetero- and Polyaromatics

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.

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.

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.

Investigating the structural chemistry of organotin(IV) compounds: recent advances

Organotin(IV) compounds have been considered for their outstanding industrial, medical and specific applications in the synthesis of various types of chemical compounds. In this review, we have focused on the structural chemistry of organotin(IV) compounds, including coordination chemistry, the effect of structure on reactions, bond formations from the perspective of structure and investigation of the structure of organotin(IV) compounds in different phases. The structural chemistry of organotin(IV) compounds is subject to interest due to their major impact on predicting the properties and drumming up support for pushing back the frontiers of synthesis of organotin(IV) compounds with advanced properties.

Recent advances in the self-assembly of polynuclear metal–selenium and –tellurium compounds from 14–16 reagents

The use of reagents containing bonds between group 14 elements and Se or Te for the self-assembly of polynuclear metal–chalcogen compounds is covered. Background material is briefly reviewed and examples from the literature are highlighted from the period 2007–2017. Emphasis is placed on the different classes of 14–16 precursors and their application in the targeted synthesis of metal–chalcogen compounds. The unique properties arising from the combination of specific 14–16 precursors, metal atoms, and ancillary ligands are also described. Selected examples are chosen to underline the progress in (i) controlled synthesis of heterometallic (ternary) chalcogen clusters, (ii) chalcogen clusters with organic functionalized surfaces, and (iii) crystalline open-framework metal chalcogenides.

Large-bite diboranes for the μ(1,2) complexation of hydrazine and cyanide

As part of our interest in the chemistry of polydentate Lewis acids as hosts for diatomic molecules, we have investigated the synthesis and coordination chemistry of bidentate boranes that feature a large boron-boron separation. In this paper, we describe the synthesis of a new example of such a diborane, namely 1,8-bis(dimesitylboryl)triptycene (2) and compare its properties to those of the recently reported 1,8-bis(dimesitylboryl)biphenylene (1). These comparative studies reveal that these two diboranes feature some important differences. As indicated by cyclic voltammetry, 1 is more electron deficient than 2; it also adopts a more compact and rigid structure with a boron-boron separation (4.566(5) Å) shorter by ∼1 Å than that in 2 (5.559(4) Å). These differences appear to dictate the coordination behaviour of these two compounds. While 2 remains inert toward hydrazine, we observed that 1 forms a very stable μ(1,2) hydrazine complex which can also be obtained by phase transfer upon layering a solution of 1 with a dilute aqueous hydrazine solution. The stability of this complex is further reflected by its lack of reaction with benzaldehyde at room temperature. We have also investigated the behaviour of 1 and 2 toward anions. In MeOH/CHCl3 (1/1 vol) both compounds selectively bind cyanide to form the corresponding μ(1,2) chelate complexes with a B-C[triple bond, length as m-dash]N-B bridge at their cores. Competition experiments in protic media show that the anionic cyanide complex formed by 1 is the most stable, with no evidence of decomplexation even in the presence of (C6F5)3B.

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.

{[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.