Some American law enforcement agencies continue to experience disruptions in the level of trust and legitimacy ascribed to them by their communities. Citizen review boards (CRBs), may be an effective ...means for improving the police-community relationship. Utilizing a framework grounded in procedural justice and citizen participation, this study examines whether a link exists between CRBs and community satisfaction in the police and four procedural justice measures: 1) trust in the police, 2) belief the police are held accountable, 3) belief the police treat all people equally, and 4) belief the police are building positive community relationships. To estimate these correlations, this study uses a unique dataset from 48 U.S. cities and employs bivariate and multivariate methods to analyze the data. The findings indicate a mostly positive association between CRBs and procedural justice measures, which suggests that CRBs may be able to bolster legitimacy and enhance the police-community relationship in some communities.
Nonprofits continue to be faced with financial challenges to fulfill their missions. Both the academic literature and nonprofit practitioners have explored revenue diversification and concentration ...strategies to meet these challenges. While these two strategies are essentially antagonistic, both have received support as being viable strategies to create better outcomes for the organization. This article examines whether revenue diversification or concentration strategies lead to greater mission outputs in a nonprofit context. Using resource dependence theory as a guiding framework, two opposing hypotheses are tested to gain more insight into the diversification versus concentration dilemma. A unique dataset is built and utilized to estimate a zero-inflated negative binomial regression model to assess the correlation between revenue diversification and mission outputs. Results indicate that revenue diversification (and not concentration) is associated with an increase in organizational outputs.
Synthetic organic chemists enjoy the luxury of having a large collection of reliable reactions at their disposal for preparing small molecules, mesoscopic structures, and polymers. Coordination ...chemists, on the other hand, are faced with the fact that transition metal chemistry, when normalized for the number of transition metals, has relatively few high‐yielding reactions, when compared to the chemistry of carbon, for preparing even small molecule structures. This lack of control is manifested, in large part, in the weak metal–ligand interactions found in coordination complexes as compared with the strong covalent bonds in organic compounds. Weak bonding often translates into many reaction pathways that are not substantially different from an energetic point of view, and therefore, results in poor selectivity. As a result, many coordination chemists in recent years have come to the realization that it may be easier and more productive to develop straightforward and reliable routes to mesoscopic supramolecular structures by capitalizing on the modest collection of high‐yielding reactions in coordination chemistry, the directional bonding afforded by metal centers, and strategies aimed at taking advantage of the weak metal bonds found in coordination complexes. Three emerging synthetic strategies, the symmetry‐interaction, directional‐bonding, and weak‐link synthetic approaches, all use metal centers as structural building blocks to rationally assemble molecular components into supramolecular metallocyclophanes. These three approaches are discussed herein, and the fundamental principles underlying each as well as their capabilities are compared and contrasted.
Supramolecular coordination complexes or coordination chemistry supramolecules? Emerging synthetic approches for the construction of supramolecular structures by coordination chemistry (see picture) have led to a rapid expansion of the field of suprarmolecular chemistry. Many structures are now accessible through the general principles that define these approaches, and the applications of the structures formed from them are beginning to be explored.
Display omitted
► We review luminescent lanthanide-containing metallopolymers. ► Metallopolymers are classified as Wolf Types I–III. ► We review potential applications of lanthanide-containing ...metallopolymers. ► The advantages and disadvantages of each are discussed.
Recent work in the area of luminescent lanthanide-containing metallopolymers has been reviewed, as well as potential applications. These hybrid materials are classified into three types, Wolf Types I–III, which are distinguished by the position of the metal center relative to the polymer backbone and the subsequent electronic interactions of the two components. These interactions, the nature of the lowest lying excited state, energy transfer processes, and non-radiative deactivation pathways must all be carefully considered when designing luminescent lanthanide-containing metallopolymers. The advantages and disadvantages of each type have been discussed.
Display omitted
•We review recent advances in the functional applications of conducting metallopolymers (CMPs).•Molecular structures based on Wolf classification and the metal-organic backbone ...interaction of CMPs are discussed.•Recent development of CMPs for use in chemical sensors, memory devices, catalysis, and organic photovoltaics are reviewed.
As promising optoelectronic materials, conducting metallopolymers (CMPs), which are hybrid polymers based on a π-conjugated organic backbone combined with a metal complex, have attracted rapidly increasing interest in recent years. In addition to the properties directly introduced to the materials by incorporating a metal complex into an organic backbone, the optical and electronic properties of CMPs can rationally be tuned by varying the strength of electronic interactions between the two components. These tunable and varied functionalities have led to applications of CMPs in many different fields, including chemical sensors, memory devices, catalysis, photovoltaics, and light-emitting diodes. Recent advances in the development of CMPs are reviewed herein along with current challenges in these fields and how the use of CMPs could potentially fulfill the requirements.
Two series of 4d-4f clusters Ln8Cd24L12(OAc)48 and Ln6Cd18L9Cl8(10)(OAc)28(26) (Ln = Nd, Gd, Er, and Yb) with novel drum-like structures were prepared using a flexible Schiff base ligand. Their NIR ...luminescence properties were determined.
Metal complexes from cobalt(II/III) ions with two tridentate ligands and the corresponding conducting metallopolymers have been synthesized, characterized and subjected to magnetic studies which ...revealed a redox-controlled spin change. These complexes were designed to contain both a possible spin-crossover metal complex core and an electropolymerizable group for the production of the corresponding conducting metallopolymers. SQUID magnetic measurements revealed a gradual thermal spin crossover (T½ = 170 K) and a low spin state up to 400 K for the two complexes with terpyridine ligand cores chelating to Co(II) and Co(III) centers, respectively, supporting the viability of a spin change from paramagnetic (Co(II), S = 3/2) to diamagnetic (Co(III), S = 0) states via redox chemistry. We have also demonstrated that the reported cobalt(II) complexes can undergo a facile polymer growth process under electropolymerization conditions. Electrochemical studies revealed that the Co(II) and Co(III) metal centers in poly-CoIIL1 could be reversibly interconverted, which demonstrates that the magnetic properties of the conducting metallopolymers can be switched between paramagnetic and diamagnetic.
Display omitted
•Electropolymerizable metal complexes with spin-crossover behavior.•Redox-induced spin change in cobalt(II) and cobalt(III) complexes.•Conducting polymers containing spin-crossover complexes.•Spin crossover and spin change with large virtual thermal hysteresis.•Redox-induced spin change in conducting metallopolymers.
A new derivative of 2,6‐bis(pyrazol‐1‐yl)pyridine (bpp) symmetrically substituted with 3,4‐ethylenedioxy‐thienyl (EDOT) substituent groups, and the corresponding ruthenium(II) complex was synthesized ...and characterized by NMR spectroscopy, elemental analysis, mass spectrometry, and single‐crystal X‐ray diffraction. A new linear conducting metallopolymer consisting of Ru(bpp‐(EDOT)2)(terpy)2+ fragments was deposited directly on to electrode surfaces as a transparent, deep red film by electrochemical coupling of the pendant EDOT moieties. XPS analysis reveals that the film has the expected structure consisting of monomer repeats without degradation or loss of metal ions. Additionally, the absorption spectrum of the polymer film shows a broad absorption range from 310 to 700 nm.
A new metal‐containing conducting metallopolymer was deposited directly on electrode surfaces as a transparent, deep red film by electrochemical coupling reaction. The metal complex is located directly in the conjugated backbone of the polymer and displays strong electronic interactions between the organic bridge and metal center. Additionally, the Ru(bpp)(terpy)2+ moieties enhance the photosensitivity of the conducting metallopolymer in the visible region.
A new class of highly luminescent nine-coordinated europium(III) tris(beta-diketonate) bis(ethylenedioxythiophene)pyrazolylpyridine (L) complexes has been synthesized and the photophysical properties ...studied: 1 = Eu(hfac)(3)(L); 2 = Eu(tta)(3)(L); 3 = Eu(btfac)(3)(L). The solid-state structure of complex 1 has been determined by single-crystal X-ray crystallography and shows the geometry of the local coordination environment around the Eu(III) ion to be a slightly distorted tricapped trigonal prism. Luminescence lifetimes were found to be 581, 473, and 576 micros for complexes 1-3, respectively. Absolute quantum yields for complexes 1-3 were measured as 16.4 +/- 1.4%, 27.5 +/- 1.2%, and 22.2% +/- 0.3%, respectively.
Metal-controlled assembly results in a series of lanthanide clusters with the formula of Ln(5)(DBM)(10)(OH)(5) x n(solvent) (DBM = dibenzoylmethanido; Ln = Nd (1), Gd (2), Er (3), and Yb (4); solvent ...= CH(3)CN or toluene). These pentanuclear clusters with square-pyramidal core structures have been characterized by X-ray diffraction analysis. Clusters 1, 3, and 4 show typical near-infrared (NIR) luminescence upon excitation at 350 nm, which represents the first examples of pentanuclear lanthanide clusters with sensitized NIR emission.
PDF
