Pyridine ligand complexes of [Bu4N][BiI4] were prepared using chelating ligands 2,2′‐bipyridyl (2,2′‐Bpy), 1,10‐phenanthroline (Phen), and 4‐nitro‐1,10‐phenanthroline (NO2Phen), producing monomeric complexes [Bu4N][(2,2′‐Bpy)BiI4], [Bu4N][(Phen)BiI4], and [Bu4N][(NO2Phen)BiI4], and bridging ligands 4,4′‐bipyridyl (4,4′‐Bpy), pyrazine (Pyz), and aminopyrazine (NH2Pyz) resulting in formation of polymers [Bu4N]n[(4,4′‐Bpy)BiI4]n and [Bu4N]2n[(RPyz)Bi2I8]n (R = H, NH2). The latter contain edge‐sharing Bi2I8 dimers. Organic ligand BiIII/CuI clusters [Bu4N]2[L2Bi2Cu2I10] {L = PPh3, P(OPh)3} and [Bu4N]2[PyBi2Cu2I10] (Py = pyridine) have been prepared. All bismuthate(III) centers are distorted octahedra and all cuprate(I) centers are tetrahedral, with organic ligands bonded to CuI. The first neutral BiI3/CuI organic ligand complex [BiCu3I6(PPh3)6] is reported. Diffuse reflectance spectroscopy measurements reveal strong absorption bands for both iodobismuthate(III) and iodocuprate(I)/bismuthate(III) complexes in the UV and visible range. Despite the similarity in absorption bands, DFT calculations support a distinct shift in transition from a mixed halide/metal‐to‐ligand charge transfer (X/MLCT) to a metal–halide cluster‐centered transition upon incorporation of copper(I) into the cluster.

Although microbial genomes harbor an abundance of biosynthetic gene clusters, there remain substantial technological gaps that impair the direct correlation of newly discovered gene clusters and their corresponding secondary metabolite products. As an example of one approach designed to minimize or bridge such gaps, we employed hierarchical clustering analysis and principal component analysis (hcapca, whose sole input is MS data) to prioritize 109 marine Micromonospora strains and ultimately identify novel strain WMMB482 as a candidate for in-depth "metabologenomics" analysis following its prioritization. Highlighting the power of current MSbased technologies, not only did hcapca enable the discovery of one new, nonribosomal peptide bearing an incredible diversity of unique functional groups, but metabolomics for WMMB482 unveiled 16 additional congeners via the application of Global Natural Product Social molecular networking (GNPS), herein named ecteinamines A−Q (1−17). The ecteinamines possess an unprecedented skeleton housing a host of uncommon functionalities including a menaquinone pathway-derived 2-naphthoate moiety, 4methyloxazoline, the first example of a naturally occurring Ψ[CH 2 NH] "reduced amide", a methylsulfinyl moiety, and a D-cysteinyl residue that appears to derive from a unique noncanonical epimerase domain. Extensive in silico analysis of the ecteinamine (ect) biosynthetic gene cluster and stable isotope-feeding experiments helped illuminate the novel enzymology driving ecteinamine assembly as well the role of cluster collaborations or "duets" in producing such structurally complex agents. Finally, ecteinamines were found to bind nickel, cobalt, zinc, and copper, suggesting a possible biological role as broad-spectrum metallophores.

Metal halide perovskites are an intriguing class of semiconductor materials being explored for their linear and non-linear optical, and potentially ferroelectric properties. In particular, layered two-dimensional Ruddlesden-Popper (RP) halide perovskites have shown non-linear optoelectronic properties. Optical second harmonic generation (SHG) is commonly used to screen for non-centrosymmetric and ferroelectric materials, however, SHG measurements of perovskites are complicated by their intense multiphoton photoluminescence (mPL) which can be mistaken for SHG signal. In this work, we introduce multidimensional harmonic generation as a method to eliminate the complications caused by mPL. By scanning and correlating both excitation and emission frequencies, we un-ambiguously assess whether a material supports SHG by examining if an emission feature scales as twice the excitation frequency. Careful multidimensional harmonic generation measurements of a series of n=2 and n=3 RP perovskites reveal that, contrary to previous belief, n-butylammonium (BA) RP perovskites display no SHG, thus they have inversion symmetry; but RP perovskites with phenylethylammonium (PEA) and 2-thiophenemethylammonium (TPMA) spacer cations display SHG. Multidimensional harmonic generation is also able to confirm the SHG and thus non-centrosymmetry of a recently reported ferroelectric RP perovskite even in the presence of an obscuring mPL background. This work establishes multidimensional harmonic generation as a definitive method to measure the SHG properties of materials and demonstrates that tuning organic cations can allow the design of new non-centrosymmetric or even ferroelectric RP perovskites. File list (2) download file view on ChemRxiv paper.pdf (2.91 MiB) download file view on ChemRxiv SI.pdf (16.17 MiB)

The observation of single-molecule magnetism in transition-metal complexes relies on the phenomenon of zero-field splitting (ZFS), which arises from the interplay of spin−orbit coupling (SOC) with ligand-field-induced symmetry lowering. Previous studies have demonstrated that the magnitude of ZFS in complexes with 3d metal ions is sometimes enhanced through coordination with heavy halide ligands (Br and I) that possess large free-atom SOC constants. In this study, we systematically probe this "heavy-atom effect" in high-spin cobalt(II)−halide complexes supported by substituted hydrotris(pyrazol-1-yl)borate ligands (Tp tBu,Me and Tp Ph,Me ). Two series of complexes were prepared: [Co II X(Tp tBu,Me )] (1-X; X = F, Cl, Br, and I) and [Co II X(Tp Ph,Me )(Hpz Ph,Me )] (2-X; X = Cl, Br, and I), where Hpz Ph,Me is a monodentate pyrazole ligand. Examination with dc magnetometry, high-frequency and -field electron paramagnetic resonance, and far-infrared magnetic spectroscopy yielded axial (D) and rhombic (E) ZFS parameters for each complex. With the exception of 1-F, complexes in the four-coordinate 1-X series exhibit positive D-values between 10 and 13 cm −1 , with no dependence on halide size. The five-coordinate 2-X series exhibit large and negative D-values between −60 and −90 cm −1 . Interpretation of the magnetic parameters with the aid of ligand-field theory and ab initio calculations elucidated the roles of molecular geometry, ligand-field effects, and metal−ligand covalency in controlling the magnitude of ZFS in cobalt−halide complexes.