Saddles as rotational locks within shape-assisted self-assembled nanosheets.

Two-dimensional (2D) materials are a key target for many applications in the modern day. Self-assembly is one approach that can bring us closer to this goal, which usually relies upon strong, directional interactions instead of covalent bonds. Control over less directional forces is more challenging and usually does not result in as well-defined materials.

Electron crystallography and dedicated electron-diffraction instrumentation.

Electron diffraction (known also as ED, 3D ED or microED) is gaining momentum in science and industry. The application of electron diffraction in performing nano-crystallography on crystals smaller than 1 µm is a disruptive technology that is opening up fascinating new perspectives for a wide variety of compounds required in the fields of chemical, pharmaceutical and advanced materials research. Electron diffraction enables the characterization of solid compounds complementary to neutron, powder X-ray and single-crystal X-ray diffraction, as it has the unique capability to measure nanometre-sized crystals.

Rapid Structure Determination of Microcrystalline Molecular Compounds Using Electron Diffraction.

Chemists of all fields currently publish about 50 000 crystal structures per year, the vast majority of which are X-ray structures. We determined two molecular structures by employing electron rather than X-ray diffraction. For this purpose, an EIGER hybrid pixel detector was fitted to a transmission electron microscope, yielding an electron diffractometer.

Structure and Bonding in Nickel-Thiolate-Iodine Charge-Transfer Complexes.

The dinuclear nickel complexes [Ni L(μ-O CR)](ClO ) [R=Me (4), R=OMe (6)], where L is a 24-membered macrocyclic N S ligand, react readily with excess I in MeCN solution at 4 °C to form stable mono-(I ) and bis-(I ) charge-transfer (CT) adducts of the type [Ni L(μ-O CR)(I ) ] (n=1 or 2) containing linear RS-I-I linkages. Three new CT compounds, namely, [Ni L(OAc)(I )](I )(I ) (5), [Ni L(O COMe)(I )](I )⋅MeCN (7⋅MeCN), and [Ni L(O COMe)(I ) ](I )⋅MeCN (8⋅MeCN) as well as the triiodide salt [Ni L(OAc)](I ) (9) were synthesized and fully characterized. A common feature of the CT adducts is a polyiodide matrix, which surrounds the individual complex molecules, stabilized by secondary I⋅⋅⋅I interactions with the CT linkages.

Adsorption of I₂ by macrocyclic polyazadithiophenolato complexes mediated by charge-transfer interactions.

The macrocyclic complex [Ni2(L)(OAc)]ClO4 (1) adsorbs up to 17 molar equivalents (>270 wt%) of iodine, although it does not exhibit permanent porosity. Vibrational spectroscopic and crystallographic studies reveal that two I2 molecules are captured by means of thiophenolate→I2 charge-transfer interactions, which enable the diffusion and sorption of further I2 molecules in a polyiodide-like network. The efficient sorption and desorption characteristics make this material suitable for accommodation, sensing, and slow release of I2.

Dependence of the chemical properties of macrocyclic [Ni(II)(2)L(μ-O(2)CR)](+) complexes on the basicity of the carboxylato coligands (L(2-) = macrocyclic N(6)S(2) ligand).

The dependence of the properties of mixed ligand [Ni(II)(2)L(μ-O(2)CR)](+) complexes (where L(2-) represents a 24-membered macrocyclic hexaamine-dithiophenolato ligand) on the basicity of the carboxylato coligands has been examined. For this purpose 19 different [Ni(II)(2)L(μ-O(2)CR)](+) complexes (2-20) incorporating carboxylates with pK(b) values in the range 9 to 14 have been prepared by the reaction of [Ni(II)(2)L(μ-Cl)](+) (1) and the respective sodium or triethylammonium carboxylates. The resulting carboxylato complexes, isolated as ClO(4)(-) or BPh(4)(-) salts, have been fully characterized by elemental analyses, IR, UV/vis spectroscopy, and X-ray crystallography.

Interplay of magnetic exchange interactions and Ni-S-Ni bond angles in polynuclear nickel(II) complexes.

The ability of bridging thiophenolate groups (RS(-)) to transmit magnetic exchange interactions between paramagnetic Ni(II) ions is examined. Specific attention is paid to complexes with large Ni-SR-Ni angles. For this purpose, dinuclear [Ni(2)L(1)(mu-OAc)I(2)][I(5)] (2) and trinuclear [Ni(3)L(2)(OAc)(2)][BPh(4)](2) (3), where H(2)L(1) and H(2)L(2) represent 24-membered macrocyclic amino-thiophenol ligands, are prepared and fully characterized by IR- and UV/Vis spectroscopy, X-ray crystallography, static magnetization M measurements and high-field electron spin resonance (HF-ESR).

Triazolopyridines as ligands: structural diversity in iron(II), cobalt(II), nickel(II) and copper(II) complexes of 3-(2-pyridyl)-[1,2,4]triazolo[4,3-a]- pyridine (L¹⁰) and spin crossover in [Fe(II)(L¹⁰)₂(NCS)₂].

The coordination chemistry of the ligand 3-(2-pyridyl)-[1,2,4]triazolo[4,3-a]pyridine (L¹⁰) has been investigated and iron(II), cobalt(II), nickel(II) and copper(II) complexes featuring diverse structural motifs have been prepared. In the 2 : 1-type complexes [Co(II)(L¹⁰)₂(MeOH)₂](ClO₄)₂ (20), [Ni(II)(L¹⁰)₂(MeOH)₂](ClO₄)₂ (21), [Cu(II)(L¹⁰)₂(MeOH)₂](ClO₄)₂ (22), [Co(II)(L¹⁰)₂(H₂O)₂](ClO₄)₂ (23) and [Cu(II)(L¹⁰)₂(ClO₄)₂] (24) the metal centres are N₄O₂ octahedrally coordinated with two N²,N(pyr) bidentate ligands L¹⁰ in the equatorial positions. In the N₆ octahedral 4 : 1-type complex [Co(II)(L¹⁰)₄](ClO₄)₂·H₂O (25) both axially coordinating N¹ unidentate and equatorially bound N²,N(pyr) bidentate ligands L¹⁰ are observed.

Crystal structure solid-state cross polarization magic angle spinning 13C NMR correlation in luminescent d10 metal-organic frameworks constructed with the 1,2-Bis(1,2,4-triazol-4-yl)ethane ligand.

Hydrothermal reactions of 1,2-bis(1,2,4-triazol-4-yl)ethane (btre) with copper(II), zinc(II), and cadmium(II) salts have yielded the dinuclear complexes [Zn2Cl4(mu2-btre)2] (1) and [Zn2Br4(mu2-btre)2] (2), the one-dimensional coordination polymer infinity1[Zn(NCS)2(2-btre)] (3), the two-dimensional networks infinity2[Cu2(mu2-Cl)2(mu4-btre)] (4), infinity2[Cu2(mu2-Br)2(mu4-btre)] (5), and infinity2{[Cd6(mu3-OH)2(mu3-SO4)4(mu4-btre)3(H2O)6](SO4).6H2O} (6), and the three-dimensional frameworks infinity3{[Cu(mu4-btre)]ClO4.0.

Trapping of a thiolate-->dibromine charge-transfer adduct by a macrocyclic dinickel complex and its conversion into an arenesulfenyl bromide derivative.

Stuck on sulfur: The first transition-metal complexes with S-Br units are surprisingly stable. Solid 3 is stable for at least six months and under vacuum solid 2 does not lose Br(2). The formation of the first structurally characterized transition-metal arenesulfenyl bromide complex 3 occurs with a change of the spin ground state from S = 2 to S = 0.

Zn-OH2 and Zn-OH complexes with hydroborate-derived tripod ligands: a comprehensive study.

The complete array of those hydrotris(pyrazolyl/thioimidazolyl)borate ligands that were developed and used in the author's laboratories, with N3, N2S, NS2, and S3 donor sets, was scanned for their ability to form Zn-OH2 and Zn-OH complexes. The coordination motifs found were Zn-OH2, Zn-OH, Zn-OH-Zn, and Zn-O2H3-Zn. Of these, the well-established Zn-OH motif was complemented with novel species bearing N3, NS2, and S3 tripods.

Preparation and characterization of mononuclear Co, Ni, and Zn complexes of dinucleating macrocyclic hexaaza-dithiophenolate ligands and their open-chain derivatives.

The preparation and characterization of mononuclear complexes of the dinucleating 24-membered hexazadithiophenolate macrocycles H2L2 and H2L3 and their open-chain N3S2 analogues H2L4 and H2L5 are reported. The highly crystalline compounds [Ni(L4)] (4), [Ni(L5)] (5), [Co(L5)] (6), [NiH2(L2)]2+ (7), [ZnH2(L2)]2+ (8), and [NiH2(L3)]2+ (9) could be readily prepared by stoichiometric complexation reactions of the hydrochlorides of the free ligands with the corresponding metal(II) dichlorides and NEt3 in methanolic solution. All complexes were characterized by X-ray crystallography.

Preparation and characterization of Cr(III), Mn(II), Fe(II), Co(II) and Ni(II) complexes of a hexaazadithiophenolate macrocycle.

The ligating properties of the 24-membered macrocyclic dinucleating hexaazadithiophenolate ligand (L(Me))2- towards the transition metal ions Cr(II), Mn(II), Fe(II), Co(II), Ni(II) and Zn(II) have been examined. It is demonstrated that this ligand forms an isostructural series of bioctahedral [(L(Me))M(II)2(OAc)]+ complexes with Mn(II) (2), Fe(II) (3), Co(II) (4), Ni(II) (5) and Zn(II) (6). The reaction of (L(Me))2- with two equivalents of CrCl2 and NaOAc followed by air-oxidation produced the complex [(L(Me))Cr(III)H2(OAc)]2+ (1), which is the first example for a mononuclear complex of (L(Me))2-.

Tris(thioimidazolyl)borate-zinc-thiolate complexes for the modeling of biological thiolate alkylations.

The S3Zn-SR coordination of thiolate-alkylating enzymes such as the Ada DNA repair protein was reproduced in tris(thioimidazolyl)borate-zinc-thiolate complexes Tti(R)Zn-SR'. Four different Tti(R) ligands and nine different thiolates were employed, yielding a total of 12 new complexes. In addition, one Tti(R)Zn-SH complex and two thiolate-bridged [Tti(R)-SEt-Tti(R)]+ complexes were obtained.

Realization of unusual ligand binding motifs in metalated container molecules: synthesis, structures, and magnetic properties of the complexes [(LMe)Ni2(mu-L')]n+ with L'=NO3-, NO2-, N3-, N2H4, pyridazine, phthalazine, pyrazolate, and benzoate.

A series of dinickel(II) complexes with the 24-membered macrocyclic hexaazadithiophenol ligand H(2)L(Me) was prepared and examined. The doubly deprotonated form (L(Me))(2-) forms complexes of the type [(L(Me))Ni2II(mu-L')](n+) with a bioctahedral N(3)Ni(II)(mu-SR)(2)(mu-L')Ni(II)N(3) core and an overall calixarene-like structure. The bridging coordination site L' is accessible for a wide range of exogenous coligands.

Carboxylate and alkyl carbonate coordination at the hydrophobic binding site of redox-active dicobalt amine thiophenolate complexes.

A series of new dicobalt complexes of the permethylated macrocyclic hexaamine dithiophenolate ligand H(2)L(Me) have been prepared and investigated in the context of ligand binding and oxidation state changes. The octadentate ligand is an effective dinucleating ligand that supports the formation of bioctahedral complexes with a central N(3)Co(mu-SR)(2)(mu-X)CoN(3) core structure, leaving a free bridging position X for the coordination of the substrates. The acetato- and cinnamato-bridged complexes [(L(Me))Co(II)(2)(mu-O(2)CMe)](+) (2) and [(L(Me))Co(II)(2)(mu-O(2)CCH=CHPh)](+) (5) were prepared by reaction of the mu-Cl complex [(L(Me))Co(II)(2)(mu-Cl)](+) (1) with the corresponding sodium carboxylates in methanol.