A Spectroscopic and Computational Evaluation of Uranyl Oxo Engagement with Transition Metal Cations.

We report the synthesis and characterization of five novel Cd2+/UO22+ heterometallic complexes that feature Cd-oxo distances ranging from 78 to 171% of the sum of the van der Waals radii for these atoms. This work marks an extension of our previously reported Pb2+/UO22+ and Ag+/UO22+ complexes, yet with much more pronounced structural and spectroscopic effects resulting from Cd-oxo interactions. We observe a major shift in the U═O symmetric stretch and significant uranyl bond length asymmetry. The ρbcp values calculated using Quantum Theory of Atoms in Molecules (QTAIM) support the asymmetry displayed in the structural data and indicate a decrease in covalent character in U═O bonds with close Cd-oxo contacts, more so than in related compounds containing Pb2+ and Ag+. Second-order perturbation theory (SOPT) analysis reveals that O spx → Cd s is the most significant orbital overlap and U═O bonding and antibonding orbitals also contribute to the interaction (U═O σ/π → Cd d and Cd s → U═O σ/π*). The overall stabilization energies for these interactions were lower than those in previously reported Pb2+ cations, yet larger than related Ag+ compounds. Analysis of the equatorial coordination sphere of the Cd2+/UO22+ compounds (along with Pb2+/UO22+ complexes) reveals that 7-coordinate uranium favors closer, stronger Mn+-oxo contacts. These results indicate that U═O bond strength tuning is possible with judicious choice of metal cations for oxo interactions and equatorial ligand coordination.

Structural, Spectroscopic, and Computational Analysis of Halogen- and Hydrogen-Bonding Effects within a Series of Uranyl Fluorides with 4-Halopyridinium.

Reported are the syntheses and characterization of five compounds containing one-dimensional uranyl fluoride chains charge balanced by 4-X-pyridinium (X = H, F, Cl, Br, I) cations. Structural analysis reveals molecular assembly via noncovalent interactions in the second coordination sphere with the X···Oyl interaction distances ranging from 2.987(7) to 3.142(3) Å, all of which are less than or close to the sum of the van der Waals radii. These interactions were probed via luminescence and Raman spectroscopy, where the latter indicates slight differences in the U═O symmetric stretches as a consequence of U═O in-phase and out-of-phase Raman-active stretches. The decrease in the X···Oyl sum of the van der Waals overlap between comparable compounds within the series manifests as a red-shifting trend among the Raman symmetric stretches. Computational density functional theory (DFT)-based frequency, electrostatic potential surfaces (ESPs), and natural bonding orbital (NBO) methods support the observed Raman spectroscopic features and provide a comprehensive rationale for assembly.

Systematic Study of Solid-State U(VI) Photoreactivity: Long-Lived Radicalization and Electron Transfer in Uranyl Tetrachloride.

Reported are the syntheses, structural characterizations, and luminescence properties of three novel [UO2Cl4]2- bearing compounds containing substituted 1,1'-dialkyl-4,4'-bipyridinum dications (i.e., viologens). These compounds undergo photoinduced luminescence quenching upon exposure to UV radiation. This reactivity is concurrent with two phenomena: radicalization of the uranyl tetrachloride anion and photoelectron transfer to the viologen which constitutes the formal transfer of one electron from [UO2Cl4]2- to the viologen species. This behavior is elucidated using electron paramagnetic resonance (EPR) spectroscopy and further probed through a series of characterization and computational techniques including Rehm-Weller analysis, time-dependent density functional theory (TD-DFT), and density of states (DOS). This work provides a systematic study of the photoreactivity of the uranyl unit in the solid state, an under-described aspect of fundamental uranyl chemistry.

Orbital Engineering Mediated by Cation Conjugation in Luminescent Uranyl-Organic Hybrid Materials.

A series of compounds of the form [HAr]2 [UO2 X4 ] is reported here, wherein Ar is systematically varied between pyridine (1-X), quinoline (2-X), acridine (3-X), 2,5-dimethylpyrazine (4-X), quinoxaline (5-X), and phenazine (6-X), and X=Cl or Br. With greater conjugation in the organic cation, a larger quenching in uranyl luminescence is observed in the solid state. Supporting our luminescence experiments with computation, we map out the potential energy diagrams for the singlet and triplet states of both the [HAr]+ cations and [UO2 Cl4 ]2- anion in the crystalline state, and of the assembly. The distinct energy transfer pathways in each compound are discussed.

Plutonium Hybrid Materials: A Platform to Explore Assembly and Metal-Ligand Bonding.

We report the synthesis of five new hybrid materials containing the [PuCl6]2- anion and charge-balancing, noncovalent interaction donating 4-X-pyridinium (X = H, Cl, Br, I) cations. Single crystals of the title compounds were grown and harvested from acidic, chloride-rich, aqueous media, and their structures were determined via X-ray diffraction. Compounds 1-4, (4XPyH)2[PuCl6], and 5, (4IPyH)4[PuCl6]·2Cl, exhibit two distinct sheet-like structure types. Structurally relevant noncovalent interactions were tabulated from crystallographic data and verified computationally using electrostatic surface potential maps and the quantum theory of atoms in molecules (QTAIM). The strength of the hydrogen and halogen bonds was quantified using Kohn-Sham density functional theory, and a hierarchy of acceptor-donor pairings was established. The PuIV-Cl bonds were studied using QTAIM and natural localized molecular orbital (NLMO) analyses to delineate the underlying bond mechanism and hybrid atomic orbital contributions therein. The results of the PuIV-Cl bond analyses were compared across compositions via analogous treatments of previously reported [PuO2Cl4]2- and [PuCl3(H2O)5] molecular units. The Pu-Cl bonds are predominately ionic yet exhibit small varying degrees of covalent character that increases from [PuCl3(H2O)5] and [PuO2Cl4]2- to [PuCl6]2-, while the participation of the Pu-based s/d and f orbitals concurrently decreases and increases, respectively.

Insight on noncovalent interactions and orbital constructs in low-dimensional antimony halide perovskites.

Reported is a series of eight antimony halide perovskite derivatives synthesized from acidic aqueous solutions of antimony oxide and halogen substituted pyridines. These materials feature anionic one-dimensional antimony halide (SbX; X = Cl, Br, I) chains or ribbons charge-balanced by organic para-halopyridinium cations (XPy; X = H, Cl, Br) which assemble into three-dimensional networks via halogen and hydrogen noncovalent interactions (NCIs) between ion pairs. Computational density functional theory (DFT) based natural bonding orbital (NBO) and density of state (DOS) methods were utilized to map the band structure and quantify and categorize noncovalent interaction strength and type. Moreover, we determined the presence of hybridized intermediate bands which are responsible for the small bandgap energies within this family and arise from mixing of the halide p-states and the Sb s-states. We note that the degree of hybridization, and thus optical properties, is influenced primarily by changes about inner sphere bonding and independent of second sphere interactions. This report is the first to specifically monitor the evolution of haloantimonate(III) hybrid perovskite atomic and molecular orbitals involved in optical behavior as a function of inner and outer sphere effects.

Pb-Oxo Interactions in Uranyl Hybrid Materials: A Combined Experimental and Computational Analysis of Bonding and Spectroscopic Properties.

Reported are the syntheses and characterization of six new heterometallic UO22+/Pb2+ compounds. These materials feature rare instances of M-oxo interactions, which influence the bonding properties of the uranyl cation. The spectroscopic effects of these interactions were measured using luminescence and Raman spectroscopy. Computational density functional theory-based natural bonding orbital and quantum theory of atoms in molecules methods indicate interactions arise predominantly through charge transfer between cationic units via the electron-donating uranyl O spx lone pair orbitals and electron-accepting Pb2+ p orbitals. The interaction strength varies as a function of Pb-oxo interaction distance and angle with energy values ranging from 0.47 kcal/mol in the longer contacts to 21.94 kcal/mol in the shorter contacts. Uranyl units with stronger interactions at the oxo display an asymmetric bond weakening and a loss of covalent character in the U═O bonds interacting closely with the Pb2+ ion. Luminescence quenching is observed in cases in which strong Pb-oxo interactions are present and is accompanied by red-shifting of the uranyl symmetric Raman stretch. Changes to inner sphere uranyl bonding manifest as a weakening of the U═O bond as a result of interaction with the Pb2+ ion. Comprehensive evaluation of the effects of metal ions on uranyl spectra supports modeling efforts probing uranyl bonding and may inform applications such as forensic signatures.

Structural Diversity of Lanthanide 3-Nitrotrispyrazolylborates: Tunable Nuclearity and Intra-Ligand Charge Transfer Sensitization of Visible and NIR Ln3+ Emission.

Reported are the syntheses, crystal structures, and photophysical properties of 28, novel lanthanide compounds across five structural types, [Ln(3-NO2Tp)2(NO3)] (1-Ln, Ln = La-Tm, except Pm), [Bu4N][Ln(3-NO2Tp)(NO3)3] (2-Ln, Ln = Yb, Lu), [Eu(3-NO2Tp)2Cl(H2O)]·2iPrOH (3-Eu), [{Ln(3-NO2Tp)2}2(µ2-CO3)]·MeOH (4-Ln, Ln = La-Gd, except Pm), and [{Ln(3-NO2Tp)}4(µ2-OMe)6(µ4-O)] (5-Ln, Ln = Pr-Tb, except Pm) with the 3-nitrotrispyrazolylborate (3-NO2Tp-) ligand. The reaction of methanol or isopropanol solutions of LnX3 (X = Cl, NO3) with the tetrabutyl ammonium salt of the flexidentate 3-NO2Tp- ([Bu4N][3-NO2Tp]) yields Ln(3-NO2Tp)x complexes of various nuclearities as either monomers (1-Ln, 2-Ln, 3-Eu), dimers (4-Ln), or tetramers (5-Ln) owing to the efficient conversion of atmospheric CO2 to CO32- (dimers) or ligand controlled solvolysis of lanthanide ions (tetramers). 3-NO2Tp- is an efficient sensitizer for both the visible and near-IR (NIR) emissions of most of the lanthanide series, except thulium. Optical measurements, supported by density functional theory calculations, indicate that the dual visible and NIR Ln3+ emission arises from two intraligand charge transfer (ILCT) transitions of 3-NO2Tp-. This is the first report of lanthanide complexes with a nitro-functionalized pyrazolylborate ligand. The derivatization of the known Tp- ligand results in new coordination chemistry governed by the increased denticity of 3-NO2Tp-, imparting remarkable structural diversity and charge transfer properties to resultant lanthanide complexes.

A Thorium Metal-Organic Framework with Outstanding Thermal and Chemical Stability.

A new thorium metal-organic framework (MOF), Th(OBA)2 , where OBA is 4,4'-oxybis(benzoic) acid, has been synthesized hydrothermally in the presence of a range of nitrogen-donor coordination modulators. This Th-MOF, described herein as GWMOF-13, has been characterized by single-crystal and powder X-ray diffraction, as well as through a range of techniques including gas sorption, thermogravimetric analysis (TGA), solid-state UV/Vis and luminescence spectroscopy. Single-crystal X-ray diffraction analysis of GWMOF-13 reveals an interesting, high symmetry (cubic Ia 3 ‾ d) structure, which yields a novel srs-a topology. Most notably, TGA analysis of GWMOF-13 reveals framework stability to 525 °C, matching the thermal stability benchmarks of the UiO-66 series MOFs and zeolitic imidazolate frameworks (ZIFs), and setting a new standard for thermal stability in f-block based MOFs.

Life-history variation along environmental and harvest clines of a northern freshwater fish: Plasticity and adaptation.

Plasticity, local adaptation and evolutionary trade-offs drive clinal variation in traits associated with lifetime growth. Disentangling the processes and determinants that cause these traits to vary helps to understand species' responses to changing environments. This is particularly urgent for exploited populations, where size-selective harvest can induce life-history evolution. Lake trout (Salvelinus namaycush) are an exploited fish with a life history adapted to low-productivity freshwaters of northern North America, which makes them highly vulnerable to ecosystem changes and overfishing. We characterized life-history variation across a broad and diverse landscape for this iconic northern freshwater fish and evaluated whether clinal variation was consistent with hypotheses for local adaptation or growth plasticity. We estimated growth-associated traits for 90 populations exposed to a diversity of environments using a Bayesian multivariate hierarchical model. We tested for clinal variation in their somatic growth, size at maturity and reproductive allocation along environmental gradients of lake productivity, climate, prey and exploitation clines under competing hypotheses of plasticity and local adaptation. Clinal life-history variation was consistent with growth plasticity and local adaptations but not harvest-induced evolution. Variation in somatic growth was explained by exploitation, climate and prey fish occurrence. Increased exploitation, from pristine to fully exploited conditions, led to increased somatic growth (from 32 to 45 mm/year) and adult life spans, and reduced age at maturity (from 11 to 8 years). Variation in size at maturity was explained by climate and, less certainly, prey fish occurrence, while reproductive allocation was explained by evolutionary trade-offs with mortality and other traits, but not environment. Lake trout life-history variation within this range was as wide as that observed across dozens of other freshwater species. Lake trout life histories resulted from evolutionary trade-offs, growth plasticity and local adaptations along several environmental clines. Presuming a plastic response, we documented ~1.4-fold growth compensation to exploitation-lower growth compensation than observed in many freshwater fishes. These results suggest that harvested species exposed to spatially structured and diverse environments may have substantial clinal variation on different traits, but due to different processes, and this has implications for their resilience and successful management.

Novel Heterometallic Uranyl-Transition Metal Materials: Structure, Topology, and Solid State Photoluminescence Properties.

Six new uranyl hybrid materials have been synthesized solvothermally utilizing the ligands 2,2'-bipyridine-3,3'-dicarboxylic acid (H2L) and 2,2':6',2''-terpyridine (TPY). The six compounds are classified as either molecular complexes (I0O0 connectivity), [(UO2)(L)(TPY)]·H2O (1), [Ni(TPY)2][(UO2)(L)2]·3H2O (2), and [Cu(TPY)2][(UO2)(L)2]·3H2O (3), or 3D metal-organic frameworks (MOFs, I0O3 connectivity), [Cu2(UO2)2(OH)(C2H3O2)(L)3(TPY)2]·6H2O (4), [Zn2(UO2)2(OH)(NO3)(C2H3O2)(L)3(TPY)2]·4H2O (5), and Na[Ni(UO2)3(OH)(O)(L)3]·9H2O (6). A discussion of the influence of transition metal incorporation, chelating effects of the ligand, and synthesis conditions on the formation of uranyl materials is presented. The structure of compound 6 is of particular note due to large channel-like voids with a diameter of approximately 19.6 Å. A topological analysis of 6 reveals a new topology with a 9-nodal 3,3,3,3,3,3,3,4,5-connected network, designated geg1 hereafter. Further, solid state photoluminescence experiments show emission and lifetimes values consistent with related uranyl compounds.

An Americium-Containing Metal-Organic Framework: A Platform for Studying Transplutonium Elements.

The synthesis, structure, and spectroscopic characterization of the first transplutonium metal-organic framework (MOF) is described. The preparation and structure of Am-GWMOF-6, [Am2 (C6 H8 O4 )3 (H2 O)2 ][(C10 H8 N2 )], is analogous to that of the isostructural trivalent lanthanide-only containing material GWMOF-6. The presented MOF architecture is used as a platform to probe Am3+ coordination chemistry and guest-enhanced luminescent emission, whereas the framework itself provides a means to monitor the effects of self-irradiation upon crystallinity over time. Presented here is a discussion of these properties and the opportunities that MOFs provide in the structural and spectroscopic study of actinides.

Restricted Speciation and Supramolecular Assembly in the 5f Block.

Hybrid materials bearing elements from the 5f block display a rich diversity of coordination geometries, connectivities, and assembly motifs. Exemplary in this regard have been uranyl coordination polymers, which feature a wide range of secondary building units resulting from hydrolysis and oligomerization of the [UO2 ]2+ cation. An alternative approach to novel materials, however, suppresses hydrolysis and relies on non-covalent interactions (e.g. hydrogen or halogen bonding) to direct assembly of a more limited suite of species or building units. This may be achieved through the use of high-anion media to promote singular actinyl anions that are assembled with organic cations, or by way of functionalized chelating ligands that produce complexes suited for assembly through peripheral donor/acceptor sites. Presented in this Concept article is therefore an overview of our efforts in this arena. We highlight examples of each approach, share our thoughts regarding delineation of assembly criteria, and discuss the opportunities for exploring structure-property relationships in these systems.

How to Bend the Uranyl Cation via Crystal Engineering.

Bending the linear uranyl (UO22+) cation represents both a significant challenge and opportunity within the field of actinide hybrid materials. As part of related efforts to engage the nominally terminal oxo atoms of uranyl cation in noncovalent interactions, we synthesized a new uranyl complex, [UO2(C12H8N2)2(C7H2Cl3O2)2]·2H2O (complex 2), that featured both deviations from equatorial planarity and uranyl linearity from simple hydrothermal conditions. Based on this complex, we developed an approach to probe the nature and origin of uranyl bending within a family of hybrid materials, which was done via the synthesis of complexes 1-3 that display significant deviations from equatorial planarity and uranyl linearity (O-U-O bond angles between 162° and 164°) featuring 2,4,6-trihalobenzoic acid ligands (where Hal = F, Cl, and Br) and 1,10-phenanthroline, along with nine additional "nonbent" hybrid materials that either coformed with the "bent" complexes (4-6) or were prepared as part of complementary efforts to understand the mechanism(s) of uranyl bending (7-12). Complexes were characterized via single crystal X-ray diffraction and Raman, infrared (IR), and luminescence spectroscopy, as well as via quantum chemical calculations and density-based quantum theory of atoms in molecules (QTAIM) analysis. Looking comprehensively, these results are compared with the small library of bent uranyl complexes in the literature, and herein we computationally demonstrate the origin of uranyl bending and delineate the energetics behind this process.

Thermochromic Uranyl Isothiocyanates: Influencing Charge Transfer Bands with Supramolecular Structure.

The synthesis and structural characterization of seven new [UO2(NCS)5]3-- and [UO2(NCS)4Cl]3--containing materials charge balanced by 4-phenylpyridinium or 4,4'-bipyridinium cations are reported. Assembly of these materials occurs via a diverse set of noncovalent interactions, with the most prevalent involving the terminal sulfur atoms, which can both accept hydrogen bonds and/or form S···S and S···Oyl interactions. The electrostatic potential of the [UO2(NCS)5]3- and [UO2(NCS)4Cl]3- anions was calculated and mapped on the 0.001 au isodensity surface to rationalize the observed assembly modes and to provide an electrostatic basis to elucidate the role of the S atoms as both donors and acceptors of noncovalent interactions. Compounds 1-7 display a range of colors (red to yellow) as well as pronounced thermochromism. A computational treatment (time-dependent density functional theory, TDDFT) of the absorbance properties supports the temperature dependence on the ratio of inter- to intramolecular ligand to metal charge transfer (LMCT) bands as obtained from UV-vis diffuse reflectance analysis. Finally, the luminescence profiles of these materials feature additional peaks atypical for most uranyl-containing materials, and a combined spectroscopic (Raman, IR, and fluorescence) and computational (harmonic frequency calculations) effort assigns these as originating from vibronic coupling between the ν1 U═O symmetric stretch and bending modes of the isothiocyanate ligands.

Transuranic Hybrid Materials: Crystallographic and Computational Metrics of Supramolecular Assembly.

Assembly of a family of 12 supramolecular compounds containing [AnO2Cl4]2- (An = U, Np, Pu), via hydrogen and halogen bonds donated by substituted 4-X-pyridinium cations (X = H, Cl, Br, I), is reported. These materials were prepared from a room-temperature synthesis wherein crystallization of unhydrolyzed and valence-pure [An(VI)O2Cl4]2- (An = U, Np, Pu) tectons is the norm. We present a hierarchy of assembly criteria based on crystallographic observations and subsequently quantify the strengths of the non-covalent interactions using Kohn-Sham density functional calculations. We provide, for the first time, a detailed description of the electrostatic potentials of the actinyl tetrahalide dianions and reconcile crystallographically observed structural motifs and non-covalent interaction acceptor-donor pairings. Our findings indicate that the average electrostatic potential across the halogen ligands (the acceptors) changes by only ∼2 kJ mol-1 across the AnO22+ series, indicating that the magnitude of the potential is independent of the metal center. The role of the cation is therefore critical in directing structural motifs and dictating the resulting hydrogen and halogen bond strengths, the former being stronger due to the positive charge centralized on the pyridyl nitrogen, N-H+. Subsequent analyses using the quantum theory of atoms in molecules and natural bond orbital approaches support this conclusion and highlight the structure-directing role of the cations. Whereas one can infer that Columbic attraction is the driver for assembly, the contribution of the non-covalent interaction is to direct the molecular-level arrangement (or disposition) of the tectons.

Engaging the Terminal: Promoting Halogen Bonding Interactions with Uranyl Oxo Atoms.

Engaging the nominally terminal oxo atoms of the linear uranyl (UO22+ ) cation in non-covalent interactions represents both a significant challenge and opportunity within the field of actinide hybrid materials. An approach has been developed for promoting oxo atom participation in a range of non-covalent interactions, through judicious choice of electron donating equatorial ligands and appropriately polarizable halogen-donor atoms. As such, a family of uranyl hybrid materials was generated based on a combination of 2,5-dihalobenzoic acid and aromatic, chelating N-donor ligands. Delineation of criteria for oxo participation in halogen bonding interactions has been achieved by preparing materials containing 2,5-dichloro- (25diClBA) and 2,5-dibromobenzoic acid (25diBrBA) coupled with 2,2'-bipyridine (bipy) (1 and 2), 1,10-phenanthroline (phen) (3-5), 2,2':6',2''-terpyridine (terpy) (6-8), or 4'-chloro-2,2':6',2''-terpyridine (Cl-terpy) (9-10), which have been characterized through single crystal X-ray diffraction, Raman, Infrared (IR), and luminescence spectroscopy, as well as through density functional calculations of electrostatic potentials. Looking comprehensively, these results are compared with recently published analogues featuring 2,5-diiodobenzoic acid which indicate that although inclusion of a capping ligand in the uranyl first coordination sphere is important, it is the polarizability of the selected halogen atom that ultimately drives halogen bonding interactions with the uranyl oxo atoms.

Syntheses, Structures, and Comparisons of Heterometallic Uranyl Iodobenzoates with Monovalent Cations.

The syntheses and crystal structures of six new heterometallic compounds containing the UO22+ cation, o-, m-, and p-iodobenzoic acid ligands, and Tl+, Rb+, and Cs+ cations which adopt the role of both charge balancing cation and secondary metal center are described, as are the luminescent properties for Tl+ containing compounds 1, 4, and 6. The structures of compounds 1-3 are isomorphous and contain uranyl monomers bound by o-iodobenzoic acid ligands with Tl+, Rb+, and Cs+ cations acting as secondary metal centers. Compounds 4 and 5 are also isomorphous and feature m-iodobenzoic acid ligands bound to the uranyl cation along with Tl+ and Rb+ cations. Compound 6 is unique in this series as it is assembled from a dimeric uranyl unit and features p-iodobenzoic acid ligands and Tl+ cations which function as charge balancing secondary metal centers. Single crystal X-ray diffraction analysis of these materials suggests that the secondary metal cations are incorporated based on the size of their ionic radius (Tl+ < Rb+ < Cs+), which is directly related to the size of the "pocket" observed in 1-6. Further, Voronoi-Dirichlet tessellation and Hirshfeld surface analysis were used to probe the coordination environment of the secondary metal centers as part of ongoing efforts to develop metrics for determining the coordination number of secondary metal cations in similar systems.

Hybrid Lanthanide-Actinide Peroxide Cage Clusters.

A cage cluster consisting of 31 uranyl and 9 Sm(3+) polyhedra self-assembles in an alkaline aqueous peroxide solution and crystallizes (U31Sm9). Trimers of Sm(3+) polyhedra are templated by µ3-η(2):η(2):η(2)-peroxide groups and link to oxo atoms of uranyl ions. Three such trimers link into a ring through uranyl hexagonal bipyramids, and these are attached through six polyhedra to a unit consisting of 21 uranyl hexagonal bipyramids to complete the cage. Luminescence spectra collected with an excitation wavelength of 420 nm reveal fine structure, which is not observed for a cluster containing only uranyl polyhedra.

Supramolecular Assembly of Molecular Rare-Earth-3,5-Dichlorobenzoic Acid-2,2':6',2″-Terpyridine Materials: Structural Systematics, Luminescence Properties, and Magnetic Behavior.

The syntheses and crystal structures of 16 new rare-earth (RE = La(3+)-Y(3+))-3,5-dichlorobenzoic acid-terpyridine molecular materials characterized via single-crystal and powder X-ray diffraction are reported. These 16 complexes consist of four unique structure types ranging from molecular dimers (La(3+) and Ce(3+)) to tetramers (Pr(3+)-Y(3+)) as one moves across the RE(3+) series. This structural evolution is accompanied by subsequent changes in modes of supramolecular assembly (halogen bonding, halogen-π, halogen-halogen, and π-π interactions). Solid-state visible and near-infrared lifetime measurements were performed on complexes 6 (Sm(3+)), 7 (Eu(3+)), 9 (Tb(3+)), 10 (Dy(3+)), 11 (Ho(3+)), 12 (Er(3+)), and 14 (Yb(3+)), and characteristic emission was observed for all complexes except 11. Lifetime data for 11, 12, and 14 suggest sensitization by the terpy antenna does occur in near-infrared systems, although not as efficiently as in the visible region. Additionally, direct current magnetic susceptibility measurements were taken for complexes 10 (Dy(3+)) and 12 (Er(3+)) and showed dominant ferromagnetic behavior.