A new synthetic route to Mg(2)Na(2)NiH(6) where a [NiH(4)] complex is for the first time stabilized by alkali metal counterions

Mg2Na2NiH6 was synthesized by reacting NaH and Mg2NiH4 at 310 degrees C under hydrogen pressure. The novel structure type was refined from neutron-diffraction data in the orthorhombic space group Pnma (No. 62), with unit cell dimensions of a = 11.428(2), b = 8.442(2), and c = 5.4165(9) Angstrom and a unit cell volume = 523 Angstrom(3) (Z = 4). The structure can be described by (Mg2H2)(2+) layers intersected by (Na2NiH4)(2-) layers. The [NiH4](4-) complex is approximately tetrahedral, indicating formal zerovalent nickel. This is the first example of a solid-state hydride where a [NiH4](4-) complex is directly stabilized by alkali metal ions instead of the more polarizing Mg(2+) ions. A rather long nickel-hydrogen bond distance of 1.65 Angstrom indicates a weaker Ni-H bond as a result of the weaker support from the less polarizing alkali metal counterions.     

Bonding and stability of the hydrogen storage material Mg(2)NiH(4)

Structural stability and bonding properties of the hydrogen storage material Mg(2)NiH(4) (monoclinic, C2/c, Z = 8) were investigated and compared to those of Ba(2)PdH(4) (orthorhombic, Pnma, Z = 8) using ab initio density functional calculations. Both compounds belong to the family of complex transition metal hydrides. Their crystal structures contain discrete tetrahedral 18 electron complexes T(0)H(4)(4-) (T = Ni, Pd). However, the bonding situation in the two systems was found to be quite different. For Ba(2)PdH(4), the electronic density of states mirrors perfectly the molecular states of the complex PdH(4)(4-), whereas for Mg(2)NiH(4) a clear relation between molecular states of TH(4)(4-) and the density of states of the solid-state compound is missing. Differences in bonding of Ba(2)PdH(4) and Mg(2)NiH(4) originate in the different strength of the T-H interactions (Pd[bond]H interactions are considerably stronger than Ni[bond]H ones) and in the different strength of the interaction between the alkaline-earth metal component and H (Ba[bond]H interactions are substantially weaker than Mg[bond]H ones). To lower the hydrogen desorption temperature of Mg(2)NiH(4), it is suggested to destabilize this compound by introducing defects in the counterion matrix surrounding the tetrahedral Ni(0)H(4)(4-) complexes. This might be achieved by substituting Mg for Al.     

关于立方晶体Mg2NiH4结构中复合体[NiH4]的几何构型

用相对论密度泛函法研究了立方晶体Mg₂NiH₄结构中复合体[NiH₄]的几何构型.晶体的环境用一个“切断”(Cut－off)的Madelung势来模拟.计算中分别假设了一个平面四边形NiH和一个四面体NiH的构型.对于平面四边形构型,计算的Ni-H键长及力常数与实验值相符;但对四面体计算的键长太短而力常数太大.研究结果表明;立方Mg₂NiH₄结构中对复合体[NiH₄]的选择是平面四边形构型,而不是四面体.     

CO(2) Dynamics in a Metal-Organic Framework with Open Metal Sites

Metal-organic frameworks (MOFs) with open metal sites are promising candidates for CO(2) capture from dry flue gas. We applied in situ(13)C NMR spectroscopy to investigate CO(2) adsorbed in Mg(2)(dobdc) (H(4)dobdc = 2,5-dihydroxyterephthalic acid; Mg-MOF-74, CPO-27-Mg), a key MOF in which exposed Mg(2+) cation sites give rise to exceptional CO(2) capture properties. Analysis of the resulting spectra reveals details of the binding and CO(2) rotational motion within the material. The dynamics of the motional processes are evaluated via analysis of the NMR line shapes and relaxation times observed between 12 and 400 K. These results form stringent and quantifiable metrics for computer simulations that seek to screen and improve the design of new MOFs for CO(2) capture.     

Structure and lithium dynamics of Li2AuSn2--a ternary stannide with condensed AuSn4/2 tetrahedra

The new stannide Li₂AuSn₂ was prepared by reaction of the elements in a sealed tantalum tube in a resistance furnace at 970 K followed by annealing at 720 K for five days. Li₂AuSn₂ was investigated by X‐ray diffraction on powders and single crystals and the structure was refined from single‐crystal data: Z=4, I4₁/amd, a=455.60(7), c=1957.4(4) pm, wR2=0.0681, 278 F² values, 10 parameters. The gold atoms display a slightly distorted tetrahedral tin coordination with Au? Sn distances of 273 pm. These tetrahedra are condensed through common corners leading to the formation of two‐dimensional AuSn_4/2 layers. The latter are connected in the third dimension through Sn? Sn bonds (296 pm). The lithium atoms fill distorted hexagonal channels formed by the three‐dimensional [AuSn₂] network. Modestly small ⁷Li Knight shifts are measured by solid‐state NMR spectroscopy that are consistent with a nearly complete state of lithium ionization. The noncubic local symmetry at the tin site is reflected by a nuclear electric quadrupolar splitting in the ¹¹⁹Sn Mössbauer spectra and a small chemical shift anisotropy evident from ¹¹⁹Sn solid‐state NMR spectroscopy. Variable‐temperature static ⁷Li solid‐state NMR spectra reveal motional narrowing effects at temperatures above 200 K, revealing lithium atomic mobility on the kHz time scale. Detailed lineshape as well as temperature‐dependent spin lattice relaxation time measurements indicate an activation energy of lithium motion of 27 kJ mol^?1.     

Structure of (NH4)3GaF6 investigated by multinuclear magic-angle spinning NMR spectroscopy in comparison with rietveld refinement

The structure of ammonium gallium cryolite (NH(4))(3)GaF(6) was investigated by (19)F and (69,71)Ga magic-angle spinning (MAS) NMR in comparison with X-ray powder diffraction followed by Rietveld refinement. In agreement with previous thermodynamic measurements, NMR experiments on (NH(4))(3)GaF(6) support the model of rigid GaF(6) octahedra. At high spinning speeds (30 kHz), the scalar coupling between the six equivalent (19)F nuclei and (69,71)Ga can be directly observed in the powder spectra. The coupling constants are J(19)F(69)Ga = 197 Hz and J(19)F(71)Ga = 264 Hz. To explain the (71)Ga spectra recorded at 3 kHz a small distribution of quadrupolar frequencies has to be included. The spread of the spinning sidebands hints to a largest nu(Q) value of 28 kHz for (71)Ga. This can be explained by the occurrence of highly symmetric GaF(6) octahedra, which are tilted against the surrounding atoms. In addition, the incomplete motional excitation does not average out the quadrupolar effects. NMR findings are in discrepancy to those of Rietveld refinement. As result it appears that X-ray diffraction is not sensitive enough to deliver proper results.     

Mg2NiH4对高氯酸铵热分解过程的影响

采用置换-扩散法制备了储氢材料Mg2NiH4, 用XRD, ICP和DSC-TG方法对其结构进行了表征. 用热分析法(DSC)研究了Mg2NiH4对高氯酸铵(AP)热分解过程的影响. 研究结果表明, Mg2NiH4对AP热分解过程有较大影响. Mg2NiH4可以显著促进AP的低温热分解过程, 降低高温热分解温度, 使DSC表观分解热明显增大. 随着加入量的增加, Mg2NiH4对AP热分解的催化促进作用增强, 当Mg2NiH4加入的质量分数为30％时, DSC表观分解热最大. 吸氢量越大, 储氢材料对AP的催化促进作用越强. Mg2NiH4催化促进AP分解过程的作用机理为: Mg2NiH4分解释放的H2及Mg和Ni与AP分解产物发生反应.     

A homologous series of alkaline earth phosphanides: syntheses,crystal structures,and unusual dynamic behavior of (THF)(n)M[P(CH(SiMe(3))(2))(C(6)H(4)-2-CH(2)NMe(2))](2) (M = Mg,Ca, Sr,Ba)

The secondary phosphine R(Me(2)NCH(2)-2-C(6)H(4))PH reacts with Bu(2)Mg to give the homoleptic complex Mg[PR(C(6)H(4)-2-CH(2)NMe(2))](2) (1) [R = CH(SiMe(3))(2)]. The analogous heavier alkaline earth metal complexes (THF)(n)Ae[PR(C(6)H(4)-2-CH(2)NMe(2))](2) [Ae = Ca (2), n = 0; Ae = Sr (3), Ba (4), n = 1] have been synthesized by metathesis reactions between K[PR(C(6)H(4)-2-CH(2)NMe(2))] and 0.5 equiv of the respective alkaline earth metal diiodide. Compounds 1-4 have been characterized by X-ray crystallography and multielement NMR spectroscopy. In the solid state, compounds 1-4 are monomeric, complexes 1 and 2 adopting a distorted tetrahedral geometry and complexes 3 and 4 adopting a distorted square pyramidal geometry (1: orthorhombic, P2(1)2(1)2(1), a = 11.413(3) A, b = 12.072(3) A, c = 32.620(11) A, Z = 4. 2: monoclinic, P2(1)/c, a = 9.5550(4) A, b = 17.4560(7) A, c = 24.5782(10) A, beta = 91.673(2) degrees, Z = 4. 3: monoclinic, C2/c, a = 15.0498(9) A, b = 13.0180(8) A, c = 24.3664(14) A, beta = 104.593(2) degrees, Z = 4. 4: monoclinic, C2/c, a = 15.2930(10) A, b = 13.0326(9) A, c = 24.6491(17) A, beta = 105.542(2) degrees, Z = 4). In toluene solution, compounds 2-4 are subject to dynamic processes which are attributed to a monomer-dimer equilibrium for which bridge-terminal exchange of the phosphanide ligands in the dimer may be frozen out at low temperatures.     

Synthesis and Crystal Structure of Bis（（2-methoxy-mercaptomethyl-benzene）hexacarbonyldiiron） Complex

The reaction of [Fe2S2(CO)6] with one equiv.of o-OCH3C6H4CH2Br under the re-duction of LiBHEt3 in dry THF afforded a tetranuclear cluster [(μ4-S){(μ-SCH2(o-OCH3)Ph)Fe2(CO)6}2](1).Complex 1 crystallizes in monoclinic,space group P21/n with a = 16.5623(6),b = 12.8265(5),c = 18.2702(7) ,β = 115.95(1)o,V = 3489.9(4) 3,Z = 4,μ = 1.87 mm-1,Dc = 1.709 Mg/m3,T = 296(2) K,C28H18Fe4O14S3,Mr = 898.03,F(000) = 1800,S = 1.10,R = 0.032 and wR = 0.058.Complex 1 consists of two diiron fragments possessing a {Fe2(CO)6} core.The two diiron units are bridged by an inorganic sulfide in a μ4-S binding mode and the sulfide is in a distorted tetrahedral geometry with the four iron atoms at each corner of the distorted tetrahedral.In its solid state,two types of non-classic intermolecular hydrogen bonding interactions plus a weak π-π stacking interaction led to a 2-D network.     

碘酸盐的晶体结构与热力学性质——(Ⅰ)碘酸盐的晶体结构特点

本文根据作者等人的实验结果并结合文献报导的数据,综述了碘酸盐及其复盐的晶体结构特点和分类。对α-LiIO_3,Li_2H(IO_3)3,Mg(IO_3)_2,Mg(IO_3)_2-LiIO_3固溶体,Zn(IO_3)_2等晶体结构变迁的情况进行了分析。阐述了由于空位数量和分布的不同,以及阳离子性质(电价、离子极化能力和离子半径等)的不同,晶格场发生变化,引起了IO_3~-在不同方向和不同程度的移动或转动,因而有可能在不同方向上形成不同程度的各种畸变型结构和超结构。     

Coordination chemistry of a new P,Te-centred ligand: synthesis, NMR spectra and X-ray structures of M(TePPri2NPPri2)2 (M = Zn, Cd, Hg)

The lithiation of the monotelluride TePPri2NP(H)Pri2 (2) with BunLi at -78 degrees C results in the formation of the reagent [LiTePPri2NPPri2] (5), which was characterized by 31P NMR spectroscopy but not isolated due to disproportionation upon solvent removal. Salt metathesis reactions of 5, generated in situ, with group 12 metal chlorides produce the complexes M(TePPri2NPPri2)2 (6, M = Zn; 7, M = Cd; 8, M = Hg), which were characterized by single crystal X-ray diffraction, multinuclear NMR spectroscopy and thermal analyses. The X-ray structures reveal distorted tetrahedral structures with two P,Te-chelating anionic ligands [TePPri2NPPri2](-). The 31P NMR spectra exhibit second order behaviour that arises from an AA'XX' spin system; the spectra were simulated to determine the 31P, 31P spin-spin coupling constants.     

Solid State Dynamics of Tricarbonyl(eta-1,5-cyclohexadienylium)iron Tetrafluoroborate and Tricarbonyl(eta-1,5-cycloheptadienylium)iron Tetrafluoroborate

The dynamic behavior of [(C(6)H(7))Fe(CO)(3)]BF(4) (I) and [(C(7)H(9))Fe(CO)(3)]BF(4) (II) in the solid state has been investigated principally by NMR spectroscopy. High-resolution variable-temperature (1)H and (13)C NMR spectra indicate that both complexes have a solid state phase transition above which there is rapid reorientation of the cyclodienylium rings and fast exchange of the carbonyl groups. The transition occurs between 253 and 263 K for I and between 329 and 341 K for II. The presence of the phase transition is confirmed by differential scanning calorimetry (DSC). (57)Fe M?ssbauer spectroscopy supports the notion that complex I is highly mobile at room temperature, while II is relatively static. The activation energy for the cyclodienylium group rotation in the high-temperature phase of I is estimated from (1)H spin-lattice relaxation time measurements to be 17.5 kJ mol(-)(1). Static (13)C NMR measurements of the solid complexes in the high-temperature phase indicate that the (13)C chemical shift anisotropies are only 20-30 ppm. This is significantly less than that expected to result from motion of individual groups and thus suggests that rotation of the whole molecule is involved. A single-crystal X-ray structural determination of complex II, at 295 K, showed that the complex is tetragonal (space group P4(1), a = 10.610(1) ?, c = 21.761(3) ?, V = 2449.7(5) ?(3), rho(calc) = 1.734 g cm(-)(3)), with eight cycloheptadienyl cations and eight tetrafluoroborate anions per unit cell. In addition, powder X-ray diffraction studies of both I and II confirm that at low temperatures both complexes have a tetragonal unit cell, which transforms to a cubic unit cell above the phase transition. The powder patterns, recorded above the phase transition, support the proposal that the complexes are undergoing whole-molecule tumbling in their dynamic regimes.     

Formation of liquid-crystalline-type structures in poly(paraamides)

It is shown that the sorption method makes it possible to quantitatively estimate the presence of ordered structures in the supramolecular structure of partially crystalline and liquid-crystalline paraamide polymers. Using ¹H NMR spectroscopy and the sorption method, the growth of liquid-crystalline type structures during spinning and thermal treatment of the poly(paraamide) fiber is analyzed. A comparison of the ¹H NMR spectra of the as-spun and heat-treated fibers at low temperatures (110–210 K) in a rigid lattice reveals that “loose” disordered microregions occur in the fiber before thermal treatment. Thermal treatment results in the “healing” of structural defects and leads to the appearance of liquid-crystalline-type structures owing to the large-scale quasi-segmental motion at a high temperature.     

Reversible photoswitching of the coordination numbers of silicon in organosilicon compounds bearing a 2-(phenylazo)phenyl group

Several organosilicon compounds bearing a 2-(phenylazo)phenyl group were synthesized from the corresponding chlorosilanes and 2-lithioazobenzene prepared by halogen-lithium transmetalation of 2-iodoazobenzene. Their structures were determined by (1)H, (13)C, (19)F, and (29)Si NMR spectra, UV-vis spectra, and X-ray crystallographic analyses. In the UV-vis spectra, silyl groups caused red shifts of both the n-pi and pi-pi transitions of the azo group compared with the transitions of the unsubstituted azobenzene. The E-isomers of the fluorosilanes showed an intramolecular interaction between a nitrogen atom of the azo group and the silicon atom, leading their intermediate structures between a distorted trigonal bipyramidal structure and a tetrahedral structure around the silicon atoms, which were revealed by the X-ray crystallographic analyses and the NMR spectra. On the other hand, silanes without fluorine atoms showed tetrahedral structures in the absence of such an interaction. The photoirradiation of the E-isomers of the fluorosilanes afforded reversibly the corresponding Z-isomers in good yields. The silicon atoms of the Z-isomers were found to be tetracoordinate in the absence of Si-N interactions by the (29)Si NMR spectra. The coordination numbers of the silicon atom of the fluorosilanes were reversibly switched between four and five by photoirradiation. These properties were compared to those of a tetrafluoro[2-(phenylazo)phenyl]silicate.     

Synthesis and Crystal Structure of 3,3＇-Bis（2-benzimidazolyl）-2,2＇-dipyridine with Hydrated Zinc（Ⅱ） Perchlorate

The reaction of Zn(ClO4)2·6H2O with 3,3'-bis(2-benzimidazolyl)-2,2'-dipyridine (L) gave a mononuclear zinc(II) complex: [ZnL2](ClO4)2·2DMF·4H2O, which was structurally characterized by EA, IR, UV, 1H NMR, fluorescence spectrum and single-crystal X-ray diffraction. The crystal (C54H54Cl2N14O14Zn, Mr = 1259.38) belongs to the monoclinic system, space group C2/c with a = 20.874(2), b = 14.9953(16), c = 20.462(3) , β = 101.553(2)°, V = 6274.8(13) 3, Z = 4, Dc = 1.333 g/cm3, F (000) = 2608, μ(MoKα) = 0.548 mm–1, R = 0.0682 and wR = 0.1931 for 4984 observed reflections with I > 2σ(I). The Zn(II) is four-coordinated in a slightly distorted tetrahedral geometry through four N atoms from four benzimidazole units of two ligands. In the crystal lattice, the [ZnL2]2+ cations are linked to each other by extensive intermolecular hydrogen bonds between nitrogen atoms of benzimidazole rings, water and DMF molecules.     

Synthesis and Crystal Structure of 3,3''-Bis(2-benzimidazolyl)-2,2''-dipyridine with Hydrated Zinc(Ⅱ) Perchlorate

The reaction of Zn(ClO4)2·6H2O with 3,3'-bis(2-benzimidazolyl)-2,2'-dipyridine (L) gave a mononuclear zinc(Ⅱ) complex: [ZnL2](ClO4)2·2DMF·4H2O, which was structurally characterized by EA, IR, UV, 1H NMR, fluorescence spectrum and single-crystal X-ray diffraction. The crystal (C54H54Cl2N14O14Zn, Mr=1259.38) belongs to the monoclinic system, space group C2/c with a=20.874(2), b=14.9953(16), c=20.462(3) (A), β=101.553(2)°, V=6274.8(13) (A)3, Z=4, Dc=1.333 g/cm3, F (000)=2608, μ(MoKα)=0.548 mm-1, R=0.0682 and Wr=0.1931 for 4984 observed reflections with Ⅰ ＞ 2σ(Ⅰ). The Zn(Ⅱ) is four-coordinated in a slightly distorted tetrahedral geometry through four N atoms from four benzimidazole units of two ligands. In the crystal lattice, the [ZnL2]2 cations are linked to each other by extensive intermolecular hydrogen bonds between nitrogen atoms of benzimidazole rings, water and DMF molecules.     

Vibrational analysis of Ag3(PO2NH)3, Na3(PO2NH)3 x H2O, Na3(PO2NH)3 x 4H2O,

FT IR and FT Raman spectra of Ag3(PO2NH), (Compound 1), Na3(PO2NH)3 x H2O (Compound II), Na3(PO2NH)3 x 4H2O (Compound III), [C(NH2)3]3(PO2NH)3 x H2O (Compound IV) and (NH4)4(PO2NH)4 x 4H2O (Compound V) are recorded and analyzed on the basis of the anions, cations and water molecules present in each of them. The PO2NH- anion ring in compound I is distorted due to the influence of Ag+ cation. Wide variation in the hydrogen bond lengths in compound III is indicated by the splitting of the v2 and v3 modes of vibration of water molecules. The NH4 ion in compound V occupies lower site symmetry and exhibits hindered rotation in the lattice. The correlations between the symmetric and asymmetric stretching vibrations of P-N-P bridge and the P-N-P bond angle have also been discussed.     

(Arene)tricarbonylchromium complexes synthesized on NaX zeolite: solid-state NMR and DRIFTS studies

Various (arene)tricarbonylchromium complexes were synthesized within the confines of NaX zeolite and studied with diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and carbon-13 magic-angle-spinning nuclear magnetic resonance (MAS NMR) spectroscopy. In each case, the surface complex Cr(CO)3(Oz)3 (Oz represents a framework oxygen of the NaX zeolite) was prepared before a particular arene was added. The arenes benzene, toluene, mesitylene, anisole, and aniline all produce hexahapto pi-complexes physisorbed within the zeolite supercage. DRIFTS spectra show three bands in the carbonyl region indicating less than C3v symmetry. The NMR spectra have narrow carbonyl bands near 240 ppm which indicate rapidly reorienting complexes within the zeolite. The (eta 6-benzene)tricarbonylchromium complex is physisorbed at two sites as indicated both by the DRIFTS spectra and by two carbonyl resonances at 242.5 and 239.1 ppm at 300 K. Variable-temperature MAS NMR shows these two resonances coalescing near 360 K with an activation energy of 48 +/- 6 kJ/mol. When the temperature is decreased to 205 K, the high-frequency carbonyl resonance disappears. The 239 ppm resonance is still narrow at 134 K while MAS sidebands show that the resonance from physisorbed benzene is ca. 200 ppm wide. The complex prepared with pyridine gave a broad resonance as indicated by the spinning sidebands in the MAS NMR spectra. The pyridine complex was identified as Cr(CO)3(C5H5N)3.     

Pentacoordinated Cu(II)/Zn(II) complexes bearing macrocyclic skeleton: synthesis, spectroscopic and molecular structure optimization studies

2,6-Diacetylpyridine and 1,2-diaminoethane in the presence of copper(II) and zinc(II) chlorides containing a few drops of acetic acid were condensed into compositions [CuLH2]2.2HCl.H2O (1), [Cu2LPyz]2.2HCl.4CH3COCH3 (2) [CuZnLPyz]2.2HCl.2CH3COCH3.10H2O (3) and [ZnL'Cl]3.3HCl.3H2O (4) substantiated by elemental analyses, IR, UV-vis, 1H NMR and FAB mass spectral data. Demetallation of a Ni(II) complex (isolated as above) afforded macrocyclic skeleton LH4, whereas L' symbolizes a skeleton of the ligand containing only ethylenediamine and 2,6-diacetylpyridine. Molecular structure optimization using MM2 force field calculations for the complexes revealed distorted square pyramidal geometry around Cu(II) centers in complexes 1 and 2 and tetrahedral geometry around Cu(II) and Zn(II) centers with different degrees of distortion in complex 3 whereas three Zn(II) atoms (each in distorted square pyramidal geometry) attached via Cl bridges form a cyclic structure in complex 4. In complexes 1 and 2,Cu-Cu = 2.63-2.66 angstroms indicated the possibility of coupling between the two Cu(II) centers which has been supported by lower magnetic moment as well as ESR spectra showing half-field signal.     

Solid-state (67)zn NMR spectroscopy in bioinorganic chemistry. Spectra of four- and six-coordinate zinc pyrazolylborate complexes obtained by management of proton relaxation rates with a paramagnetic dopant

Solid-state (67)Zn NMR spectra of model compounds for metalloproteins, such as [H(2)B(3,5-Me(2)pz)(2)](2)Zn (pz denotes pyrazolyl ring), have been obtained using low temperatures (10 K) to enhance the Boltzmann factor in combination with cross polarization (CP) from (1)H to (67)Zn. Attempts to observe spectra of other model compounds, such as [H(2)B(pz)(2)](2)Zn, were hindered by long relaxation times of the protons. To decrease the proton relaxation times, the high-spin six-coordinate complex [HB(3,4,5-Me(3)pz)(3)](2)Fe has been investigated as a dopant. NMR and EPR measurements have shown that this Fe(II) dopant effectively reduces the (1)H spin lattice relaxation time, T(1), of the zinc samples in the temperature range 5-10 K with minimal perturbations of the (1)H spin lattice relaxation time in the rotating frame, T(1)(rho). Using this methodology, we have determined the (67)Zn NMR parameters of four- and six-coordinate zinc(II) poly(pyrazolyl)borate complexes that are useful models for systems of biological importance. The (67)Zn NMR parameters are contrasted to the corresponding changes in the (113)Cd NMR parameters for the analogous compounds. Further, these investigations have demonstrated that a temperature-dependent phase transition occurs in the neighborhood of 185 K for [HB(3,5-Me(2)pz)(3)](2)Zn; the other poly(pyrazolyl)borate complexes we investigated did not show this temperature-dependent behavior. This conclusion is confirmed by a combination of room-temperature high-field (18.8 T) solid-state (67)Zn NMR spectroscopy and low-temperature X-ray methods. The utilization of paramagnetic dopants should enable low-temperature cross polarization experiments to be performed on a wide variety of nuclides that are important in bioinorganic chemistry, for example, (25)Mg, (43)Ca, and (67)Zn.