Tetrahedral Centers Research Articles

Zinc Complexes of Bipyrrolidine‐Based Diamine‐Diphenolato and Diamine‐Diolato Ligands: Predetermination of Helical Chirality Around Tetrahedral Centres

AbstractThe coordination chemistry of chiral tetradentate dianionic ligands of the diamine‐diphenolato and diamine‐diolato families having the (R,R)‐2,2′‐bipyrrolidine core around ZnII was investigated. Reactions with diethylzinc led to complexes of the type [{ONNO}Zn] for most ligands and to bridging dinuclear complexes of the type [μ‐Lig4(ZnEt)2] for one of the diamine‐diolato ligands. Reactions with bis(hexamethyldisilazide)zinc led to complete conversions. Most complexes were obtained as mononuclear complexes. The least bulky Salan ligand, Lig3, led to an equilibrium between mononuclear and dinuclear complexes in noncoordinating solvents. All ligands were found to wrap around the tetrahedral zinc with very high diastereoselectivities supporting predetermined chiral induction from the bipyrrolidine core to the helical ligand wrapping. Molecular structures determined by single‐crystal X‐ray diffraction for two complexes of the type [{ONNO}Zn] substantiated the predicted Δ wrapping of the (R,R)‐based ligands. In contrast, representative Salan and diamine‐diolato ligands assembled around the trans‐1,2‐diaminocyclohexane core led to diastereomer mixtures of the corresponding complexes.

Water-soluble scorpionate ligands and their reactions with molybdenum complexes. Crystal structures of lithium tris(3-isopropylpyrazol-1-yl)methanesulfonate and MoVOCl3(OPPh3)2·MoVIO2Cl2(OPPh3)2

The water soluble ligands, lithium and potassium tris(3-isopropylpyrazol-1-yl)methanesulfonate (LiTpms i Pr and KTpms i Pr) and potassium hydrotris(3-carboxyethyl-5-methylpyrazol-1-yl)borate (), have been prepared and their reactions with simple Mo-containing starting material investigated. The crystal structure of LiTpms i Pr·1.2MeOH consists of dinuclear units containing two distinctly different, four-coordinate, tetrahedral Li centers coordinated by bidentate κ2 N,O-Tpms i Pr− and methanol. The ligands fail to coordinate to aqueous molybdate under neutral to acidic conditions. Reaction of with MoO2Cl2(OPPh3)2 results in reduction and formation of MoVOCl3(OPPh3)2·MoVIO2Cl2(OPPh3)2. The crystal structure of this binary mixture revealed distorted octahedral molecules in crystallographically distinct sites.

Toward Understanding the Catalytic Synergy in the Design of Bimetallic Molecular Sieves for Selective Aerobic Oxidations

Structure-property correlations and mechanistic implications are important in the design of single-site catalysts for the activation of molecular oxygen. In this study we rationalize trends in catalytic synergy to elucidate the nature of the active site through structural and spectroscopic correlations. In particular, the redox behavior and coordination geometry in isomorphously substituted, bimetallic VTiAlPO-5 catalysts are investigated with a view to specifically engineering and enhancing their reactivity and selectivity in aerobic oxidations. By using a combination of HYSCORE EPR and in situ FTIR studies, we show that the well-defined and isolated oxophilic tetrahedral titanium centers coupled with redox-active VO(2+) ions at proximal framework positions provide the loci for the activation of oxidant that leads to a concomitant increase in catalytic activity compared to analogous monometallic systems.

Hydroxylation of silica nanoclusters (SiO2)M(H2O)N, M = 4, 8, 16, 24: stability and structural trends

Employing global optimisation and ab initio calculations, we follow the step-wise molecular hydroxylation of (SiO2)M(H2O)N, M = 4, 8, 16, 24, cluster species from their anhydrous state up to a N:M ratio (R(N/M)) of ≥0.5. Increasing N from zero for low R(N/M) values, significantly and progressively, energetically stabilises all cluster sizes. In all cases, this initial steep decrease in energy levels off at a well-defined threshold R(N/M) value to a linear regime where the decrease in energy per hydroxylation by a water molecule reaches a stable minimum value. Analysis of the structures of the globally optimised clusters for each size, M, and hydroxylation, N, reveals that the initially anhydrous cluster structures have increasingly tetrahedral SiO4 centres until the transition to the linear hydroxylation regime, whereupon the average deviation from tetrahedrality starts to increase. With increasing R(N/M) the smaller clusters (M = 4, 8) tend to open up and incorporate increasing numbers of Si-OH groups, seemingly approaching the limit of separate Si(OH)4 monomers. The larger clusters considered (M = 16, 24), however, are more resistant to structural disruption and with increasing R(N/M) energetically prefer not to form more Si-OH groups but, instead to form hydrogen bonds with subsequent water molecules on their surfaces. Such behaviour is also found to be more energetically favourable than the formation of fully-hydroxylated Si16O24(OH)16 and Si24O36(OH)24 cage isomers for R(N/M) = 0.5. We further found that the threshold R(N/M) value at which the transition to the linear hydroxylation regime is encountered follows an inverse power law with respect to increasing cluster size M which may indicate the existence of a more general fundamental basis underlying our results.

Ce4Ag3Ge4O0.5 – chains of oxygen-centered [OCe2Ce2/2] tetrahedra embedded in a [CeAg3Ge4] intermetallic matrix

The oxidation of an intermetallic phase under high-pressure/high-temperature conditions led to the synthesis of Ce4Ag3Ge4O(0.5) exhibiting [OCe2Ce(2/2] tetrahedral chains, in which the oxygen atoms statistically occupy the tetrahedral centres. Starting from a 1:1:1 CeAgGe precursor (NdPtSb type), a multianvil high-pressure/high-temperature experiment at 11.5 GPa and 1250-1300 °C revealed Ce4Ag3Ge4O(0.5), crystallizing in the space group Pnma with the following lattice parameters: a = 2087.3(4), b = 439.9(1), and c = 1113.8(2) pm. Magnetic measurements showed Curie-Weiss behavior above 100 K with an experimental magnetic moment of 2.42 µB per Ce atom, close to the value for the free Ce(3+) ion, clearly indicating trivalent cerium in Ce4Ag3Ge4O(0.5). Full potential GGA+U band structure calculations resulted in metallic properties and a magnetic ground state with one unpaired 4f-electron per cerium in agreement with the experiments.

Two New (3,6)-Connected Frameworks Based on an Unsymmetrical Tritopic Pyridyldicarboxylate Ligand and Co2 Dimer: Structures, Magnetic, and Sorption Properties

By reacting a tritopic ligand 5-(4-carboxyphenyl)nicotinic acid (H2cpna) with Co(NO3)2 under different conditions, two new three-dimensional (3D) frameworks, [Co2(cpna)2(H2O)3]·DMF·9(H2O) (1) and [Co4(cpna)4(H2O)8] (2), have been obtained. They exhibit (3,6)-connected topological nets based on Co2 clusters and Y-shaped trinodal cpna2– linkers. 1 presents a chiral anh net with the right-handed helical channels, while 2 shows an achiral framework with a rtl topology. The whole structures of 1 and 2 are constructed from 2D achiral layers interconnected by triangular cpna2– nodes. Notably, these layers contain two heterochiral vertical and parallel 21 helical chains for 1 and 2, respectively, and those chains are constructed with 4-connected tetrahedral or square planar centers in their respective layers. The magnetic studies indicate that 1 and 2 show antiferromagnetic and weak ferromagnetic exchanges transmitted through μ2-Owater/μ1,3-carboxylate bridges and carboxylate single μ2-O bridges between Co2+ ions...

Synthesis and Reaction Chemistry of Sb(ECH2CH2NMe2)3 (E = O, S)

AbstractThe antimony aminoalkoxide and aminothiolates Sb(ECH2CH2NMe2)3 [E = O (1), S (2)] were synthesized and their ability to form adducts with other metal moieties investigated. Compound 1 forms 1:1 adducts with NiI2 (3) and M(acac)2 [M = Cd (4), Ni (5)], while 2 undergoes ligand exchange with AlMe3 to afford Me2AlSCH2CH2NMe2 (6). The structures of 2–4 and 6 were determined. Compound 2 incorporates three S, N‐chelating ligands though the interaction with nitrogen is weaker than in analogous alkoxide complexes. Product 3 reveals one iodine has migrated from nickel to antimony, and all three alkoxide ligands bridge the two metals through μ2‐O atoms. In contrast, in 4, only one alkoxide links the antimony and cadmium. Compound 6 adopts the same structure, a chelating S,N ligand generating a tetrahedral center at aluminum, as known tBu2AlSCH2CH2NR2 species (R = Me, Et).

Conformational analysis of triphenylphosphine in square planar organometallic complexes: [(PPh3)(ML1L2L3)] and [M(acac)(L′)(PPh3)

The conformation analysis of free PPh(3) and PPh(3) coordinated to tetrahedral, trigonal-bipyramidal, octahedral or square planar achiral metal centres is discussed. Results from ADF calculations, in agreement with experimental structures, show that favoured degenerate conformations of complex-bound PPh(3) in square planar [(PPh(3))(ML(1)L(2)L(3))] and [M(acac)(L')(PPh(3))] complexes can be obtained by applying the following principles (P helicity, view along P-M axis), (i) superimpose C(ortho) of the vertical ring A onto the nadir plane perpendicular to the square plane and allow ring A to tilt towards the smallest ligand, (ii) allow ring B to tilt in the space below the smallest ligand in the quadrant between the nadir plane below the complex and a horizontal plane through the SQP of the complex, (iii) tilt ring C over the largest ligand and (iv) allow correlated tilting of rings A, B and C to minimize inter ring-ring and inter ring-ligand interactions.

Framework reconstruction between hR8 and cI16 germaniums: A molecular dynamics study

Using molecular dynamics simulations and a Density Functional based Tight Binding method, the metastable germanium allotropes hR8 and cI16 are shown to interconvert by means of two sets of quasi-1D chains. The first set hosts sequences of SN2 inversions of Ge tetrahedral centers, and represents the activated step. The second set does not imply any reconstruction, but assists the first one in propagating the reconstruction. The overall process is commenced by bond nucleation, followed by chain formation and reconstruction into either structure. A novel intermediate metastable phase is visited in the process. Elementary steps of chemical reactivity are accessible due to the appropriate time and spatial resolution of the methods used. This paves the way for a chemical understanding of structure reconstruction and metastable phase formation in solid materials.

Cp*(PiPr3)RuOTf: A Reagent for Access to Ruthenium Silylene Complexes

The ruthenium triflate complex Cp*(PiPr3)RuOTf (1) was generated from the reaction of Cp*(PiPr3)RuCl with Me3SiOTf in dibutyl ether. Complex 1 reacted with primary and secondary silanes to produce a family of Ru(IV) silyl dihydride complexes of the type Cp*(PiPr3)Ru(H)2(SiRR′OTf) (3–12). Structural analyses of complexes 8 (R = R′ = Ph) and 12 (R = R′ = fluorenyl) revealed the presence of a tetrahedral silicon center and a four-legged piano stool geometry about ruthenium. Anion abstraction from Cp*(PiPr3)Ru(H)2(SiHROTf) by [Et3Si·toluene][B(C6F5)4] afforded hydrogen-substituted cationic ruthenium silylene complexes [Cp*(PiPr3)Ru(H)2(═SiHR)][B(C6F5)4] (R = Mes (13), R = Si(SiMe3) (14)) that display a significant Ru–H···Si interaction, as indicated by relatively large 2JSiH coupling constants (2JSiH = 58.2 Hz (13), 2JSiH = 37.1 Hz (14)). The syntheses of secondary silylene complexes [Cp*(PiPr3)Ru(H)2(═SiRR′)][B(C6F5)4] (R = R′ = Ph (15); R = Ph, R′ = Me (16), R = R′ = fluorenyl (17)) were also achieved by anion abstraction with [Et3Si·toluene][B(C6F5)4]. Complexes 15–17 do not display strong Ru–H···Si secondary interactions, as indicated by very small 2JSiH coupling constant values.

La equivalencia entre las paridades de los intercambios de dos sustituyentes y las reflexiones especulares, en la determinación de la quiralidad de átomos tetraédricos: ¡Una demostración con espejos!

La quiralidad, de la palabra griega cheir que significa mano, es la propiedad de un objeto de no poder superponerse con su objeto imagen en el espejo. En las moléculas orgánicas esta propiedad se debe, en algunos casos, a la presencia de un carbono quiral (llamado también centro quiral, centro estereogénico o carbono asimétrico), un carbono tetraédrico que soporta cuatro sustituyentes diferentes (Eliel, 1994a). Los sustituyentes enlazados a ese átomo de carbono solamente pueden ser arreglados en el espacio de dos maneras diferentes (figura 1). Con el fin de distinguirlas, en 1956, Cahn, Ingold y Prelog propusieron un sistema de nomenclatura (conocido como nomenclatura absoluta)

Dynamic properties of the fluxional Rh2H(μ-PPh2)2(PPh3)3−1 complex

The rhodium dimer [Rh2H(PPh2)2(PPh3)3]− was prepared from RhCl(PPh3)3 and K4Sn9 in the presence of 2,2,2-cryptand in ethylenediamine/toluene solvent mixtures. The [K(2,2,2-crypt)]+ salt was isolated and characterized via NMR and X-ray diffraction studies. The solid state structure reveals a binuclear, diphenylphosphido-bridged, 32 electron Rh(I)–Rh(I) complex with edge-shared tetrahedral and square planar Rh centers with overall Cs point symmetry. 1-D and 2-D 1H, 31P, and 31P{1H} NMR experiments were used to characterize the complex.

Silver coordination networks and cages based on a semi-rigid bis(isoxazolyl) ligand

The semi-rigid ligand 1,4-bis((3,5-dimethylisoxazol-4-yl)methyl)benzene (bisox) reacts with a range of silver(i) salts to give products in which the anions dictate the structure. The reactions with AgNO(3) and AgO(2)CCF(3) both lead to compounds in which the anions are coordinated to the silver centres. Thus, the structure of [Ag(2)(NO(3))(2)(bisox)] 1 contains helical silver-nitrate chains that are linked into sheets by bridging bisox ligands, whereas the structures of [Ag(O(2)CCF(3))(bisox)]·0.5X (2a, X = MeOH; 2b, X = MeCN) consist of sheets in which Ag(2)(μ-O(2)CCF(3))(2) dimers act as 4-connecting nodes. In these structures bisox adopts the S-conformation, with the nitrogen donor atoms anti to each other. The reactions of bisox with AgClO(4) and AgBF(4) in methanol give the compounds [Ag(2)(bisox)(3)]X(2) (3, X = ClO(4); 5, X = BF(4)), the structures of which contain triply-interpenetrated sheets with Borromean links and ligands in the S-conformation. Recrystallisation of these compounds from acetonitrile-diethyl ether gives [Ag(2)(bisox)(3)]X(2)·xEt(2)O (4, X = ClO(4), x = 1; 6, X = BF(4), x = 1.2). The structures of 4 and 6 contain similar triply-interpenetrated sheets to those in 3 and 5, though these are sandwiched between sheets of discrete Ag(2)(bisox)(3) cages, in which the bisox ligands are in the C-conformation, with the nitrogen donor atoms syn to each other. Diethyl ether molecules project through the faces of the cages and template cage formation. Both 4 and 6 lose diethyl ether on heating in vacuum, and convert into 3 and 5, respectively. This solid state transformation requires a change in conformation of half the bisox ligands, with conversion of 6 into 5 occurring more readily than conversion of 4 into 3. The reactions of bisox with AgPF(6) and AgSbF(6) in methanol give mixtures of products from which [Ag(bisox)(2)]X·0.5bisox (7, X = PF(6); 8, X = SbF(6)) can be isolated. Both 7 and 8 have structures containing one-dimensional chains, in which the bisox ligands adopt C-conformations and interconnect distorted tetrahedral silver centres in a pairwise manner generating macrocycles. Additional uncoordinated bisox molecules lie within half of these macrocyclic rings. Recrystallisation of the crude AgSbF(6)/bisox reaction mixture from acetonitrile-diethyl ether gives [Ag(bisox)(2)]SbF(6)9, the structure of which consists of a triply-interpenetrated flattened diamondoid network. A similar structure was observed for [Ag(bisox)(2)]CF(3)SO(3)10, which is formed from the reaction of AgO(3)SCF(3) and bisox in methanol.

Bis(allyl)aluminum Cation, Tris(allyl)aluminum, and Tetrakis(allyl)aluminate: Synthesis, Characterization, and Reactivity

Cationic, neutral, and anionic aluminum allyl compounds were synthesized, and their reactivity toward electrophiles was studied. The THF adduct of the previously elusive tris(allyl)aluminum, [Al(η1-C3H5)3(THF)] (1), was isolated as an oil. Protonolysis of one allyl ligand in 1 using [NEt3H][BPh4] gave the cationic bis(allyl)aluminum, a fragment of the crystalline [Al(η1-C3H5)2(THF)3−n]+[BPh4]−·(n+1)THF (n = 0, 1) (2). Single-crystal X-ray diffraction of [Al(η1-C3H5)2(THF)2]+[BPh4]− (2a) revealed a tetrahedral aluminum center, while [Al(η1-C3H5)2(THF)3]+[BPh4]− (2b) contains a trigonal-bipyramidal aluminum center with both allyl ligands in the equatorial plane. The tetrakis(allyl)aluminate K+[Al(η1-C3H5)4]− (3) was also synthesized from the reaction of 1 with K(C3H5). Reactions of the allyl compounds 1−3 with (i) benzophenone, (ii) allyl halides C3H5X (X = Cl, Br, I), and (iii) halogen X2 (X = Br, I) showed considerable difference with respect to the ionic charge of the aluminum allyl.

D∞h B2(BS)2−/2− and Td B(BS)4−: Boron sulfide clusters containing BB multiple bonds and B− tetrahedral centers

AbstractA density functional theory investigation on the geometrical and electronic properties of B4S (B2(BS)) and B5S (B(BS)) clusters has been performed in this work. Both the doublet B2(BS) ([SBBBBS]−) (D∞h, 2Πu) and the singlet B2(BS) ([SBBBBS]2−) (D∞h, 1Σ) proved to have perfect linear ground‐state structures containing a multiply bonded BB core (BB or BB) terminated with two BS groups, while Td B(BS) turned out to possess a perfect B− tetrahedral center directly corrected to four BS groups, similar to the corresponding boron hydride molecules of D∞h B2H, D∞h B2H, and Td BH, respectively. B4S2 and B5S4 neutrals, however, appeared to be much different: they favor a planar fan‐shaped C2v B4S2 (a di‐S‐bridged B4 rhombus) and a planar kite‐like C2v B5S4 (a di‐S‐bridged B3 triangle bonded to two BS groups), respectively. One‐electron detachment energies and symmetrical stretching vibrational frequencies are calculated for D∞h B2(BS) and Td B(BS) monoanions to facilitate their future characterizations. Neutral salts of B2(BS)2Li2 with an elusive BB triple bond and B(BS)4Li containing a tetrahedral B− center are predicted possible to be targeted in experiments. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010

ChemInform Abstract: Syntheses and Structures of a Series of Very Low Coordinate Barium Compounds: Ba(N(SiMe3)2)2(THF)2, (Ba(N(SiMe3)2)2(THF))2, and (Ba(N( SiMe3)2)2)2.

Barium hexamethyldisilazide tetrahydrofuranate, Ba(N(SiMe{sub 3}){sub 2}){sub 2}(THF){sub 2} (1), is synthesized from barium granules and 1,1,1,3,3,3-hexamethyldisiliazane at 25{degree}C in THF. Gaseous ammonia is a necessary catalyst. In the solid state, the compound is a monomer containing a tetrahedral four-coordinate barium center. One of the coordinated THF molecules is removed from 1 by stripping a toluene solution of 1 to dryness in vacuo, yielding (Ba(N(SiMe{sub 3}){sub 2}){sub 2}(THF)){sub 2} (2). In the solid state, 2 is a dimer containing two bridging and two terminal hexamethyldisilamido groups. The four-coordinate, tetrahedral geometry at each barium is completed by terminal THF molecules. The solvent-free compound (Ba(N(SiMe{sub 3}){sub 2}){sub 2}){sub 2} (3) is obtained by sublimation of 1. This compound is a dimer in the solid state, with three-coordinate barium centers. Crystal data are reported for all these compounds 14 refs., 3 figs., 9 tabs.

Iron‐Containing Poly(propylene imine) Dendromesogens with Photoactive Properties

AbstractHere, we report the first results of investigation the local structure and photoactive properties of iron‐containing dendromesogens based on decyloxybenzoate substituted poly(propylene imine) dendrimers of the first to fifth generations. Iron ions existing in a high‐spin state are coordinated in dendrimer ligands by two kinds of iron‐complexing sites with an octahedral and a tetrahedral symmetry. Octahedral (high‐symmetry) centers are located at the border of the dendrimeric core, while the tetrahedral centers with strong rhombic distortion of iron environment are distributed throughout all branching of the dendrimeric core. It has been found that all iron‐containing dendromesogens exhibit light‐harvesting and fluorescence properties.magnified image

Volatile, Monomeric, and Fluorine‐Free Precursors for the Metal Organic Chemical Vapor Deposition of Zinc Oxide

AbstractTwo new bis(ketoiminato)zinc(II) compounds that show excellent precursor properties for the chemical vapor deposition (CVD) of zinc oxide materials are presented. The synthesis of the ketoiminato zinc complexes [Zn{[(CH2)xOCH3]NC(CH3)=C(H)C(CH3)=O}2] (1: x = 2; 2: x = 3) is straightforward and can easily be scaled up. Compounds 1 and 2 were analyzed by 1H and 13C NMR spectroscopy, elemental analysis, single‐crystal X‐ray diffraction analysis, and electron ionization mass spectrometry. The compounds exist as monomers with a distorted tetrahedral zinc center. Thermogravimetric studies, sublimation, and solubility tests reveal very promising properties for metal–organic CVD related applications. Preliminary metal–organic CVD experiments with the use of compound 1 were performed as a screening for the suitability of the new bis(ketoiminato)zinc complexes as precursors for the growth of ZnO thin films in the presence of oxygen. The films were characterized by X‐ray diffraction, scanning electron microscopy, energy dispersive analysis of X‐ray, and Rutherford backscattering measurements. The as‐deposited ZnO films were stoichiometric; the crystalline films exhibited strong preferred orientation along the c‐axis.

Water structure theory and some implications for drug design.

The development of theories of water structure has been hindered in the past by the difficulty of experimental measurement. Both measurement and computer modelling studies have now reached the stage where theoretical treatments of water structure are converging to a broadly acceptable model. In current understanding, water is a mixture of randomly hydrogen-bonded molecules and larger structures comprised of tetrahedral oxygen centres which, when hydrogen-bonded to each other, lead to five-membered and other rings which can aggregate to form three-dimensional structures. Evidence is taken from studies of the ices, from clathrates and other solid solutions, as well as from liquid solutions, that certain motifs occur very frequently and have relatively high stability, such as the (H2O)20 cavity-forming structure known from studies on clathrates. The implications of recent models of water structure for an understanding of biological events, including the interactions of drugs with receptors, are profound. It is becoming clear that modelling of aqueous solutions of any molecule must consider the explicit interactions with water molecules, which should not be regarded as a continuum: water itself is not a continuum. Solute molecules which possess hydrogen-bonding groups will provoke the formation of further hydrogen-bonding chains of water molecules: if these can form rings, such ringswilltend to persist longerthan chains, givingthesolute a secondary identity of associated water which may play a role in molecular recognition. Solutes that do not have hydrogen-bonding capability, or regions of solutes which are non-polar, may also produce partial cage-like water structures that are characteristic of the solute. The classification of many solutes as structure makers or structure breakers has relevance to the interactions between ligands and large biomolecules such as proteins. While it is generally accepted that sulfate and urea, respectively structure maker and breaker, may alter protein conformation through effects on water, it has not been recognised that bioactive ligands, which also change the conformation of proteins, may do so by a related, but more selective, mechanism. Very early studies of cell contents suggested that the associated water might be different from bulk water, a concept that lost support in the mid-20th century. Current theories of water structure may invite a reappraisal of this position, given the observation that structuring may extend for many molecular diameters from an ordered surface.

Synthesis and Characterization of 6,6′-(2,4,6-Triisopropylphenyl)-2,2′-bipyridine (tripbipy) and Its Complexes of the Late First Row Transition Metals

The synthesis of tripbipy, a new substituted bipyridine ligand (6,6'-(2,4,6-triisopropylphenyl)-2,2'-bipyridine), and the syntheses, structures, and magnetic properties of the first coordination compounds based on this ligand are described. Tripbipy was synthesized by the Suzuki coupling of 2,4,6-triisopropylphenyl boronic acid and 6,6'-dibromo-2,2'-bipyridine. Reported here are the tripbipy complexes of five late first row transition metal chlorides (MCl(2); M = Fe, Co, Ni, Cu, Zn). Four of the complexes MCl(2)tripbipy (M = Fe, Co, Ni, Zn) crystallize in the space group P2(1)/c and are isomorphous with one solvent molecule of crystallization. The complex CuCl(2)tripbipy crystallizes in the space group P2(1)2(1)2(1) with two solvent molecules of crystallization. All MCl(2)tripbipy complexes are four coordinate and contain distorted tetrahedral metal centers. CuCl(2)tripbipy shows a pseudo Jahn-Teller distortion, and X-band electron paramagnetic resonance (EPR) in a toluene glass gives approximate g( perpendicular, parallel) values of 2.2 and 2.1. Magnetic measurements (M = Fe, Co, Ni, Cu) are consistent with high spin d(n) configurations (n = 6-9, S = 2, 3/2, 1, 1/2) tetrahedral complexes and give chi(M)T values at 300 K of 3.56, 2.10, 1.01, and 0.37 cm(3) M(-1) K, respectively.