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Item Calculation of chemical-shift tensors of heavy nuclei: a DFT/ZORA investigation of 199Hg chemical-shift tensors in solids, and the effects of cluster size and electronic-state approximations(Royal Society of Chemistry, 2014-06-02) Alkan, Fahri; Dybowski, Cecil; Fahri Alkan and C. Dybowski; Alkan, Fahri; Dybowski, C.Calculations of the nuclear magnetic resonance chemical-shielding tensors of a suite of mercury-containing materials using various cluster models for the structures provide a stringent test of the procedures for forming models and for calculation with various methods. The inclusion of higher co-ordination shells in the molecular clusters permits quantum chemical calculations of 199Hg chemical-shielding tensor elements within 3% of the experimental values. We show that it is possible to reduce the size of computationally expensive molecular-cluster calculations with limited effect on calculated NMR parameters by carefully introducing the frozen core approximation. The importance of the relativistic Hamiltonian for accurate predictions of chemical-shielding values is demonstrated within the molecular cluster approach. The results demonstrate that careful design of a cluster to represent the solid-state structure, inclusion of relativistic components in the Hamiltonian at least at the spin–orbit level, and judicious use of approximations are essential to obtain good agreement with experimental results.Item Coordination geometry of lead carboxylates – spectroscopic and crystallographic evidence(Royal Society of Chemistry, 2014-12-14) Catalano, Jaclyn; Murphy, Anna; Yao, Yao; Yap, Glenn P. A.; Zumbulyadis, Nicholas; Centeno, Silvia A.; Dybowski, Cecil; Jaclyn Catalano, Anna Murphy, Yao Yao, Glenn P. A. Yap, Nicholas Zumbulyadis, Silvia A. Centeno and Cecil Dybowski; Catalano, Jaclyn; Murphy, Anna; Yao, Yao; Yap, Glenn P. A.; Dybowski, CecilDespite their versatility, only a few single-crystal X-ray structures of lead carboxylates exist, due to difficulties with solubility. In particular, the structures of long-chain metal carboxylates have not been reported. The lone electron pair in Pb(II) can be stereochemically active or inactive, leading to two types of coordination geometries commonly referred to as hemidirected and holodirected structures, respectively. We report 13C and 207Pb solid-state NMR and infrared spectra for a series of lead carboxylates, ranging from lead hexanoate (C6) to lead hexadecanoate (C18). The lead carboxylates based on consistent NMR parameters can be divided in two groups, shorter-chain (C6, C7, and C8) and longer-chain (C9, C10, C11, C12, C14, C16, and C18) carboxylates. This dichotomy suggests two modes of packing in these solids, one for the short-chain lead carboxylates and one for long-chain lead carboxylates. The consistency of the 13C and 207Pb NMR parameters, as well as the IR data, in each group suggests that each motif represents a structure characteristic of each subgroup. We also report the single-crystal X-ray diffraction structure of lead nonanoate (C9), the first single-crystal structure to have been reported for the longer-chain subgroup. Taken together the evidence suggests that the coordination geometry of C6–C8 lead carboxylates is hemidirected, and that of C9–C14, C16 and C18 lead carboxylates is holodirected.Item Adsorption of 2-propanol on ice probed by ambient pressure X-ray photoelectron spectroscopy(Royal Society of Chemistry, 2015-08-18) Newberg, John T.; Bluhm, Hendrik; John T. Newberg and Hendrik Bluhm; Newberg, John T.The interaction of 2-propanol with ice was examined via ambient pressure X-ray photoelectron spectroscopy (APXPS), a surface sensitive technique that probes the adsorbed 2-propanol directly with submonolayer resolution. Isothermal uptake experiments were performed on vapor deposited ice at 227 K in the presence of the equilibrium water vapor pressure of 0.05 Torr and 2-propanol partial pressures ranging from 5 × 10−5 to 2 × 10−3 Torr. The C 1s APXPS spectra of adsorbed 2-propanol showed two characteristic peaks associated with the COH alcohol group and CMe methyl groups in a 1 : 2 ratio, respectively. Coverage increased with 2-propanol partial pressure and followed first order Langmuir kinetics with a Langmuir constant of K = 6.3 × 103 Torr−1. The 1 : 2 ratio of COH : CMe remained constant with increasing coverage, indicating there is no chemical reaction upon adsorption. The observed Langmuir kinetics using APXPS is consistent with previous observations of other small chain alcohols via indirect adsorption methods using, e.g., Knudsen cell and coated wall flow tube reactors. Graphical abstract: Adsorption of 2-propanol on ice probed by ambient pressure X-ray photoelectron spectroscopyItem Dinuclear copper(I) complexes with N-heterocyclic thione and selone ligands: synthesis, characterization, and electrochemical studies(Royal Society of Chemistry, 2015-08-18) Kimani, Martin M.; Watts, David; Graham, Leigh A.; Rabinovich, Daniel; Yap, Glenn P. A.; Brumaghim, Julia L.; Martin M. Kimani, David Watts, Leigh A. Graham, Daniel Rabinovich, Glenn P. A. Yap and Julia L. Brumaghim; Yap, Glenn P. A.The synthesis, characterization, and structures of a series of homoleptic and heteroleptic copper(I) complexes supported by N-heterocyclic chalcogenone ligands is reported herein. The quasi-reversible Cu(II/I) reduction potentials of these copper complexes with monodentate (dmit or dmise) and/or bidentate (BmmMe, BsemMe, BmeMe, BseeMe) chalcogenone ligands are highly dependent upon the nature and number of the donor groups and can be tuned over a 470 mV range (−369 to 102 mV). Copper–selone complexes have more negative Cu(II/I) reduction potentials relative to their thione analogs by an average of 137 mV, and increasing the number of methylene units linking the heterocyclic rings in the bidentate ligands results in more negative reduction potentials for their copper complexes. This ability to tune the copper reduction potentials over a wide range has potential applications in synthetic and industrial catalysis as well as the understanding of important biological processes such as electron transfer in blue copper proteins and respiration.Item Mechanism-based design of labile precursors for chromium(I) chemistry(Royal Society of Chemistry, 2015-08-27) Akturk, Eser S.; Yap, Glenn P. A.; Theopold, Klaus H.; Eser S. Akturk, Glenn P. A. Yap and Klaus H. Theopold; Akturk, Eser Sahin; Yap, Glenn P. A.; Theopold, Klaus H.Dinitrogen complexes of the type TpR,RCr–N2–CrTpR,R are not the most labile precursors for Cr(I) chemistry, as they are sterically protected from obligatory associative ligand substitution. A mononuclear alkyne complex – TptBu,MeCr(g2-C2(SiMe3)2) – proved to be much more reactive.Item Chemical-shift tensors of heavy nuclei in network solids: a DFT/ZORA investigation of 207Pb chemical-shift tensors using the bond-valence method(Royal Society of Chemistry, 2015-09-02) Alkan, Fahri; Dybowski, Cecil; Fahri Alkan and C. Dybowski; Alkan, Fahri; Dybowski, CecilCluster models are used in calculation of 207Pb NMR magnetic-shielding parameters of α-PbO, β-PbO, Pb3O4, Pb2SnO4, PbF2, PbCl2, PbBr2, PbClOH, PbBrOH, PbIOH, PbSiO3, and Pb3(PO4)2. We examine the effects of cluster size, method of termination of the cluster, charge on the cluster, introduction of exact exchange, and relativistic effects on calculation of magnetic-shielding tensors with density functional theory. Proper termination of the cluster for a network solid, including approximations such as compensation of charge by the bond-valence (BV) method, is essential to provide results that agree with experiment. The inclusion of relativistic effects at the spin–orbit level for such heavy nuclei is an essential factor in achieving agreement with experiment.Item Cr−Cr Quintuple Bonds: Ligand Topology and Interplay Between Metal−Metal and Metal−Ligand Bonding(American Chemical Society, 2015-10-26) Falceto, Andrés; Theopold, Klaus H.; Alvarez, Santiago; Andrés Falceto, Klaus H. Theopold, and Santiago Alvarez; Theopold, Klaus H.Chromium–chromium quintuple bonds seem to be approaching the lower limit for their bond distances, and this computational density functional theory study tries to explore the geometrical and electronic factors that determine that distance and to find ways to fine-tune it via the ligand choice. While for monodentate ligands the Cr–Cr distance is predicted to shorten as the Cr–Cr–L bond angle increases, with bridging bidentate ligands the trend is the opposite, since those ligands with a larger number of spacers between the donor atoms favor larger bond angles and longer bond distances. Compared to Cr–Cr quadruple bonds, the quintuple bonding in Cr2L2 compounds (with L a bridging bidentate N-donor ligand) involves a sophisticated mechanism that comprises a positive pyramidality effect for the σ and one π bond, but a negative effect for one of the δ bonds. Moreover, the shorter Cr–Cr distances produce a mismatch of the bridging ligand lone pairs and the metal acceptor orbitals, which results in a negative correlation of the Cr–Cr and Cr–N bond distances in both experimental and calculated structures.Item Cyclophilin A stabilizes the HIV-1 capsid through a novel non-canonical binding site(Nature Publishing Group, 2016-03-04) Liu, Chuang; Perilla, Juan R.; Ning, Jiying; Lu, Manman; Hou, Guangjin; Ramalho, Ruben; Himes, Benjamin A.; Zhao, Gongpu; Bedwell, Gregory J.; Byeon, In-Ja; Ahn, Jinwoo; Gronenborn, Angela M.; Prevelige, Peter E.; Rousso, Itay; Aiken, Christopher; Polenova, Tatyana; Schulten, Klaus; Zhang, Peijun; Chuang Liu, Juan R. Perilla, Jiying Ning, Manman Lu, Guangjin Hou, Ruben Ramalho, Benjamin A. Himes, Gongpu Zhao, Gregory J. Bedwell, In-Ja Byeon, Jinwoo Ahn, Angela M. Gronenborn, Peter E. Prevelige, Itay Rousso, Christopher Aiken, Tatyana Polenova, Klaus Schulten & Peijun Zhang; Lu, Manman; Hou, Guangjin; Polenova, TatyanaThe host cell factor cyclophilin A (CypA) interacts directly with the HIV-1 capsid and regulates viral infectivity. Although the crystal structure of CypA in complex with the N-terminal domain of the HIV-1 capsid protein (CA) has been known for nearly two decades, how CypA interacts with the viral capsid and modulates HIV-1 infectivity remains unclear. We determined the cryoEM structure of CypA in complex with the assembled HIV-1 capsid at 8-Å resolution. The structure exhibits a distinct CypA-binding pattern in which CypA selectively bridges the two CA hexamers along the direction of highest curvature. EM-guided all-atom molecular dynamics simulations and solid-state NMR further reveal that the CypA-binding pattern is achieved by single-CypA molecules simultaneously interacting with two CA subunits, in different hexamers, through a previously uncharacterized non-canonical interface. These results provide new insights into how CypA stabilizes the HIV-1 capsid and is recruited to facilitate HIV-1 infection.Item Quorum sensing regulators are required for metabolic fitness in Vibrio parahaemolyticus(American Society for Microbiology, 2017-01-09) Kalburge, Sai Siddarth; Carpenter, Megan R.; Rozovsky, Sharon; Boyd, E. Fidelma; Sai Siddarth Kalburge, Megan R. Carpenter, Sharon Rozovsky and E. Fidelma Boyd; Kalburge, Sai Siddarth; Carpenter, Megan R.; Rozovsky, Sharon; Boyd, E. FidelmaQuorum sensing (QS) is a process by which bacteria alter gene expression in response to cell density changes. In Vibrio species, at low cell density, the sigma 54-dependent response regulator LuxO, is active, and regulates the two QS master regulators AphA, which is induced and OpaR, which is repressed. At high cell density the opposite occurs, LuxO is inactive, therefore OpaR is induced and AphA is repressed. In V. parahaemolyticus, a significant enteric pathogen of humans, the role of these regulators in pathogenesis is less known. We examined deletion mutants of luxO, opaR and aphA for in vivo fitness using an adult mouse model. We found that the luxO and aphA mutants were defective in colonization compared to wild-type. The opaR mutant did not show any defect in vivo. Colonization was restored to wild-type levels in a luxO/opaR double mutant and was also increased in an opaR/aphA double mutant. These data suggest that AphA is important and that overexpression of opaR is detrimental to in vivo fitness. RNA-seq analysis of the wild-type and luxO mutant grown in mouse intestinal mucus showed that 60% of the genes that were downregulated in the luxO mutant were involved in amino acid and sugar transport and metabolism. These data suggest that the luxO mutant has a metabolic disadvantage, which was confirmed by growth pattern analysis using phenotype microarrays. Bioinformatics analysis revealed OpaR binding sites in the regulatory region of 55 carbon transporter and metabolism genes. Biochemical analysis of five representatives of these regulatory regions demonstrated direct binding of OpaR in all five tested. These data demonstrate the role of OpaR in carbon utilization and metabolic fitness, an overlooked role in the QS regulon.Item Quorum sensing regulators are required for metabolic fitness in Vibrio parahaemolyticus(American Society for Microbiology Journals, 2017-01-09) Kalburge, Sai Siddarth; Carpenter, Megan R.; Rozovsky, Sharon; Boyd, E. Fidelma; Sai Siddarth Kalburge, Megan R. Carpenter, Sharon Rozovsky, E. Fidelma Boyd; Kalburge, Sai Siddarth; Carpenter, Megan R.; Rozovsky, Sharon; Boyd, E. FidelmaQuorum sensing (QS) is a process by which bacteria alter gene expression in response to cell density changes. In Vibrio species, at low cell density, the sigma 54-dependent response regulator LuxO, is active, and regulates the two QS master regulators AphA, which is induced and OpaR, which is repressed. At high cell density the opposite occurs, LuxO is inactive, therefore OpaR is induced and AphA is repressed. In V. parahaemolyticus, a significant enteric pathogen of humans, the role of these regulators in pathogenesis is less known. We examined deletion mutants of luxO, opaR and aphA for in vivo fitness using an adult mouse model. We found that the luxO and aphA mutants were defective in colonization compared to wild-type. The opaR mutant did not show any defect in vivo. Colonization was restored to wild-type levels in a luxO/opaR double mutant and was also increased in an opaR/aphA double mutant. These data suggest that AphA is important and that overexpression of opaR is detrimental to in vivo fitness. RNA-seq analysis of the wild-type and luxO mutant grown in mouse intestinal mucus showed that 60% of the genes that were downregulated in the luxO mutant were involved in amino acid and sugar transport and metabolism. These data suggest that the luxO mutant has a metabolic disadvantage, which was confirmed by growth pattern analysis using phenotype microarrays. Bioinformatics analysis revealed OpaR binding sites in the regulatory region of 55 carbon transporter and metabolism genes. Biochemical analysis of five representatives of these regulatory regions demonstrated direct binding of OpaR in all five tested. These data demonstrate the role of OpaR in carbon utilization and metabolic fitness, an overlooked role in the QS regulon.Item Structural Analysis of Human Cofilin 2/Filamentous Actin Assemblies: Atomic-Resolution Insights from Magic Angle Spinning NMR Spectroscopy(Nature Publishing Group, 2017-03-17) Yehl, Jenna; Kudryashova, Elena; Reisler, Emil; Kudryashov, Dmitri; Polenova, Tatyana; Jenna Yehl, Elena Kudryashova, Emil Reisler, Dmitri Kudryashov & Tatyana Polenova; Polenova, TatyanaCellular actin dynamics is an essential element of numerous cellular processes, such as cell motility, cell division and endocytosis. Actin’s involvement in these processes is mediated by many actinbinding proteins, among which the cofilin family plays unique and essential role in accelerating actin treadmilling in filamentous actin (F-actin) in a nucleotide-state dependent manner. Cofilin preferentially interacts with older filaments by recognizing time-dependent changes in F-actin structure associated with the hydrolysis of ATP and release of inorganic phosphate (Pi) from the nucleotide cleft of actin. The structure of cofilin on F-actin and the details of the intermolecular interface remain poorly understood at atomic resolution. Here we report atomic-level characterization by magic angle spinning (MAS) NMR of the muscle isoform of human cofilin 2 (CFL2) bound to F-actin. We demonstrate that resonance assignments for the majority of atoms are readily accomplished and we derive the intermolecular interface between CFL2 and F-actin. The MAS NMR approach reported here establishes the foundation for atomic-resolution characterization of a broad range of actin-associated proteins bound to F-actin.Item Chemometric Software supporting NSF Project Variable Selection for Remedying the Effects of Uncontrolled Variation in Data Driven Predictions(Steven D. Brown, 2019-09-15) Poerio, Dominic V.; Kneale, Casey; Brown, Steven D.Item Iron Oxidation by a Fused Cytochrome-Porin Common to Diverse Iron-Oxidizing Bacteria(mBio, 2021-07-27) Keffer, Jessica L.; McAllister, Sean M.; Garber, Arkadiy I.; Hallahan, Beverly J.; Sutherland, Molly C.; Rozovsky, Sharon; Chan, Clara S.Iron (Fe) oxidation is one of Earth’s major biogeochemical processes, key to weathering, soil formation, water quality, and corrosion. However, our understanding of microbial contribution is limited by incomplete knowledge of microbial iron oxidation mechanisms, particularly in neutrophilic iron oxidizers. The genomes of many diverse iron oxidizers encode a homolog to an outer membrane cytochrome (Cyc2) shown to oxidize iron in two acidophiles. Phylogenetic analyses show Cyc2 sequences from neutrophiles cluster together, suggesting a common function, though this function has not been verified in these organisms. Therefore, we investigated the iron oxidase function of heterologously expressed Cyc2 from a neutrophilic iron oxidizer Mariprofundus ferrooxydans PV-1. Cyc2PV-1 is capable of oxidizing iron, and its redox potential is 208 ± 20 mV, consistent with the ability to accept electrons from Fe2+ at neutral pH. These results support the hypothesis that Cyc2 functions as an iron oxidase in neutrophilic iron-oxidizing organisms. The results of sequence analysis and modeling reveal that the entire Cyc2 family shares a unique fused cytochrome-porin structure, with a defining consensus motif in the cytochrome region. On the basis of results from structural analyses, we predict that the monoheme cytochrome Cyc2 specifically oxidizes dissolved Fe2+, in contrast to multiheme iron oxidases, which may oxidize solid Fe(II). With our results, there is now functional validation for diverse representatives of Cyc2 sequences. We present a comprehensive Cyc2 phylogenetic tree and offer a roadmap for identifying cyc2/Cyc2 homologs and interpreting their function. The occurrence of cyc2 in many genomes beyond known iron oxidizers presents the possibility that microbial iron oxidation may be a widespread metabolism.Item Photo-activatable Ub-PCNA probes reveal new structural features of the Saccharomyces cerevisiae Polη/PCNA complex(Nucleic Acids Research, 2021-08-14) Shen, Siqi; Davidson, Gregory A; Yang, Kun; Zhuang, ZhihaoThe Y-family DNA polymerase η (Polη) is critical for the synthesis past damaged DNA nucleotides in yeast through translesion DNA synthesis (TLS). TLS is initiated by monoubiquitination of proliferating cell nuclear antigen (PCNA) and the subsequent recruitment of TLS polymerases. Although individual structures of the Polη catalytic core and PCNA have been solved, a high-resolution structure of the complex of Polη/PCNA or Polη/monoubiquitinated PCNA (Ub-PCNA) still remains elusive, partly due to the disordered Polη C-terminal region and the flexibility of ubiquitin on PCNA. To circumvent these obstacles and obtain structural insights into this important TLS polymerase complex, we developed photo-activatable PCNA and Ub-PCNA probes containing a p-benzoyl-L-phenylalanine (pBpa) crosslinker at selected positions on PCNA. By photo-crosslinking the probes with full-length Polη, specific crosslinking sites were identified following tryptic digestion and tandem mass spectrometry analysis. We discovered direct interactions of the Polη catalytic core and its C-terminal region with both sides of the PCNA ring. Model building using the crosslinking site information as a restraint revealed multiple conformations of Polη in the polymerase complex. Availability of the photo-activatable PCNA and Ub-PCNA probes will also facilitate investigations into other PCNA-containing complexes important for DNA replication, repair and damage tolerance.Item Light and microwave driven spin pumping across FeGaB–BiSb interface(Physical Review Materials, 2021-12-16) Sharma, Vinay; Wu, Weipeng; Bajracharya, Prabesh; To, Duy Quang; Johnson, Anthony; Janotti, Anderson; Bryant, Garnett W.; Gundlach, Lars; Jungfleisch, M. Benjamin; Budhani, Ramesh C.Three-dimensional (3D) topological insulators (TIs) with large spin Hall conductivity have emerged as potential candidates for spintronic applications. Here, we report spin to charge conversion in bilayers of amorphous ferromagnet (FM) Fe78Ga13B9 (FeGaB) and 3D TI Bi85Sb15 (BiSb) activated by two complementary techniques: spin pumping and ultrafast spin-current injection. DC magnetization measurements establish the soft magnetic character of FeGaB films, which remains unaltered in the heterostructures of FeGaB-BiSb. Broadband ferromagnetic resonance (FMR) studies reveal enhanced damping of precessing magnetization and large value of spin mixing conductance (5.03×1019m–2) as the spin angular momentum leaks into the TI layer. Magnetic field controlled bipolar DC voltage generated across the TI layer by inverse spin Hall effect is analyzed to extract the values of spin Hall angle and spin diffusion length of BiSb. The spin pumping parameters derived from the measurements of the femtosecond light-pulse-induced terahertz emission are consistent with the result of FMR. The Kubo-Bastin formula and tight-binding model calculations shed light on the thickness-dependent spin-Hall conductivity of the TI films, with predictions that are in remarkable agreement with the experimental data. Our results suggest that room temperature deposited amorphous and polycrystalline heterostructures provide a promising platform for creating novel spin orbit torque devices.Item Experimental and Theoretical Study on the Substitution Patterns in Lithium Germanides: The Case of Li15Ge4 vs Li14ZnGe4(European Journal of Inorganic Chemistry, 2021-12-23) Osman, Hussien H.; Bobev, SvilenA new ternary lithium zinc germanide, Li13.83Zn1.17(2)Ge4, was synthesized by a high-temperature solid state reaction of the respective elements. The crystal structure was determined by single-crystal X-ray diffraction methods. The new phase crystallizes in the body-centered cubic space group /43d 3d (no. 220) with unit cell parameter of 10.695(1) Å. The crystal structure refinements show that the parent Li15Ge4 structure is stabilized as Li15−xZnxGe4 (x≈1) via random substitution of Li atoms by the one-electron-richer atoms of the element Zn, by virtue of which the number of valence electrons increases, leading to a more electronically stable system. The substitution effects in the parent Li15Ge4 structure were investigated through both theory and experiment, which confirm that the Zn atoms in this structure prefer to occupy only one of the two available crystallographic sites for Li. The preferred substitution pattern established from experimental results is supported by DFT electronic structure calculations, which also explore the subtleties of the chemical bonding and the electronic properties of the title compounds.Item Mirror-plane disorder in a nickel chloride Schiff base complex: a suitable case study for crystallographic instruction(Acta Crystallographica Section C: Structural Chemistry, 2022-01-27) Hsuan, Chang; Chen, Wen-Ching; Shen, Jiun-Shian; Ong, Tiow-Gan; Wang, Vincent C.-C.; Yap, Glenn P. A.The nickel chloride complex of the Schiff base N2,N20-propanediylbis(2,3-butanedione-2-imine-3-oxime), namely, chlorido(3,9-dimethylundeca-3,8-diene-2,10-dione 10-oxime 2-oximato- 4N,N0,N00,N000)nickel(II), [NiCl(C 11 H19 N4 O2 )], at 100 K crystallizes in the orthorhombic space group Cmce. The structure exhibits mirror disorder of the main molecule that is not present in the bromide analogue. The relatively small number of unique reflections in the data set and the disorder imposed by the crystallographic mirror plane present a challenging educational case study.Item Calcium Substitution in Rare-earth Metal Germanides with the Gd5Si4 Type Structure(Journal of Inorganic and General Chemistry, 2022-02-23) Suen, Nian-Tzu; Bobev, SvilenAn extended series of rare-earth metal calcium germanides have been synthesized and structurally characterized. The compounds have the general formula RE5−xCaxGe4 (1.5Item Natural Product Synthesis by Intramolecular Alkylidene Carbene C−H Insertion(European Journal of Organic Chemistry, 2022-03-15) Taber, Douglass F.Direct functionalization of unactivated C−H bonds is of increasing importance in organic synthesis. Of the many methods that have been developed, intramolecular alkylidene C−H insertion, proceeding with retention of absolute configuration, is among the most versatile. This Review explores all examples of the use of intramolecular alkylidene C−H insertion in natural product synthesis.Item A molecular substitutional disorder case study suitable for instruction: L2CrII(THF)/L2[(trimethylsilyl)methyl]CrIII (L is 2,5-bis{[(2,6-diisopropylphenyl)imino]methyl}pyrrol-1-ide)(Acta Crystallographica Section C: Structural Chemistry, 2022-04-06) Salisbury, Brian A.; Young, John F.; Theopold, Klaus H.; Yap, Glenn P. A.A solution of CrII and CrIII complexes, bis(2,5-bis{[(2,6-diisopropylphenyl)imino]methyl}pyrrol-1-ido)(tetrahydrofuran)chromium(II)–bis(2,5-bis{[(2,6-diisopropylphenyl)imino]methyl}pyrrol-1-ido)[(trimethylsilyl)methyl]chromium(III) (0.88/0.12), [Cr(C30H38N3)2(C4H8O)]0.88[Cr(C30H38N3)2(C4H11Si)]0.12 or L2CrII(THF)/L2[(trimethylsilyl)methyl]CrIII (L = 2,5-bis{[(2,6-diisopropylphenyl)imino]methyl}pyrrol-1-ide and THF is tetrahydrofuran), in pentane crystallizes in the monoclinic space group P21/c. The structure obtained shows most of the atoms coincident but with THF disordered with the (trimethylsilyl)methyl ligand. Structures with this disorder, involving more than two or three atoms, seem to appear rarely in the literature; however, in this case, the data set is ideal for the crystallographic instruction of molecular substitution disorder.