14221-06-8Relevant articles and documents
Cotton, F. Albert,Matonic, John H.,Silva, Denise de O.
, (1995)
Dimolybdenum tetracarboxylates as auxiliary chromophores in chiroptical studies of vic-diols
Jawiczuk, Magdalena,Gorecki, Marcin,Suszczynska, Agata,Karchier, Michal,Jazwinski, Jaroslaw,Frelek, Jadwiga
, p. 8250 - 8263 (2013)
The aim of the present work was to check the suitability of dimolybdenum carboxylates, other than commonly used [Mo2(OAc)4], as auxiliary chromophores for determining the absolute configuration of optically active vic-diols by means of electronic circular dichroism (ECD). To this end, a set of dimolybdenum tetracarboxylates was synthesized, and subsequently, the two most promising compounds were selected, namely dimolybdenum tetrakis(μ-pivalate) and tetrakis(μ-isovalerate). The selection was based on their solubility in commonly used solvents, their stability in solution, their tolerance to air exposure, as well as their utility for dichroic studies. The stability of the obtained in situ chiral complexes was verified by measuring the dependence of ECD, UV-vis, and NMR spectra on time, temperature, and concentration. We have shown that the ECD spectra of diverse vic-diols with these complexes are suitable for configurational assignment based on the correlation between signs of Cotton effects (CEs) arising in the spectra and the stereostructure of the ligand. Furthermore, to aid in the interpretation of experimental results, a separate set of DFT calculations has been incorporated to provide additional insight into the structure of the chiral complexes involved. In contrast to the earlier assumptions, experiments showed that the chelating mode of ligation is preferred for the studied complexes.
Hierarchically Ordered Two-Dimensional Coordination Polymers Assembled from Redox-Active Dimolybdenum Clusters
Claire, F. James,Tenney, Stephanie M.,Li, Minyuan M.,Siegler, Maxime A.,Wagner, Justine S.,Hall, Anthony Shoji,Kempa, Thomas J.
, p. 10673 - 10676 (2018)
Coordination polymers (CPs) supporting tunable through-framework conduction and responsive properties are of significant interest for enabling a new generation of active devices. However, such architectures are rare. We report a redox-active CP composed of two-dimensional (2D) lattices of coordinatively bonded Mo2(INA)4 clusters (INA = isonicotinate). The 2D lattices are commensurately stacked and their ordering topology can be synthetically tuned. The material has a hierarchical pore structure (pore sizes distributed between 7 and 33 ?) and exhibits unique CO2 adsorption (nominally Type VI) for an isotherm collected at 195 K. Furthermore, cyclic voltammetry and electrokinetic analyses identify a quasi-reversible feature at E1/2 = -1.275 V versus ferrocene/ferrocenium that can be ascribed to the [Mo2(INA)4]0/-1 redox couple, with an associated standard heterogeneous electron transfer rate constant ks = 1.49 s-1. The tunable structure, porosity, and redox activity of our material may render it a promising platform for CPs with responsive properties.
Preparation of core-shell coordination molecular assemblies via the enrichment of structure-directing codes of bridging ligands and metathesis of metal units
Park, Jinhee,Chen, Ying-Pin,Perry, Zachary,Li, Jian-Rong,Zhou, Hong-Cai
, p. 16895 - 16901 (2014)
A series of molybdenum- and copper-based MOPs were synthesized through coordination-driven process of a bridging ligand (3,3′-PDBAD, L1) and dimetal paddlewheel clusters. Three conformers of the ligand exist with an ideal bridging angle between the two carboxylate groups of 0° (H2α-L1), 120°(H2β-L1), and of 90°(H2γ-L1), respectively. At ambient or lower temperature, H2L1 and Mo2(OAc)4 or Cu2(OAc)4 were crystallized into a molecular square with γ-L1 and Mo2/Cu2 units. With proper temperature elevation, not only the molecular square with γ-L1 but also a lantern-shaped cage with α-L1 formed simultaneously. Similar to how Watson-Crick pairs stabilize the helical structure of duplex DNA, the core-shell molecular assembly possesses favorable H-bonding interaction sites. This is dictated by the ligand conformation in the shell, coding for the formation and providing stabilization of the central lantern shaped core, which was not observed without this complementary interaction. On the basis of the crystallographic implications, a heterobimetallic cage was obtained through a postsynthetic metal ion metathesis, showing different reactivity of coordination bonds in the core and shell. As an innovative synthetic strategy, the site-selective metathesis broadens the structural diversity and properties of coordination assemblies.
Syntheses and structures of di(carboxylato)hexakis(acetonitrile)-dimolybdenum(II) bis(tetrafluoroborate) and trans-[di(μ-acetato)-di(acetonitrile)di(μ-bis(diphenylphosphino)amine) dimolybdenum (II)] bis(tetrafluoroborate)
Cotton, F. Albert,Kühn, Fritz E.
, p. 257 - 264 (1996)
Di(carboxylato)hexakis(acetonitrile)dimolybdenum(II) bis(tetrafluoroborate) s, [Mo2(μ-O2CR)2(CH3CN) 6](BF4)2(R = CH3,CH2Cl, C(CH3)3, CF3) (3a-d), are easily accessible by reacting [Mo2(CH3CN)8](BF4)4 (2) with a stoichiometric amount or a slight excess of the appropriate carboxylic acid and anhydride in acetonitrile. A large excess of carboxylic acid leads to the formation of tetracarboxylates. As an example cis-[Mo2(μ-O2CCH2Cl)2(CH 3CN)6](BF4)2 (3b) has been structurally characterized. Crystallographic data are as follows: space group: I42d (No. 122), a = b = 10.733(2), c = 59.448(5) A?, V = 6848(2) A?3, Z = 8, d(Mo-Mo) = 2.140(1) A?. Trans-[Mo2(μ-O2CCH3)2(dppa) 2(CH3CN)2](BF4)2 (4) can be synthesized from cis-[Mo2(μ-O2CCH3)2(CH 3CN)6](BF4)2 (3a) and bis(diphenylphosphino)amine (dppa) at room temperature. This result contradicts earlier reports where bulky diphosphines such as dppm (sterically very similar to dppa) did not lead to bis-diphosphine products. Furthermore our results indicate that in all the syntheses reported to date for [Mo2(μ-O2CCH3)2(LL) 2](BF4)2 type-compounds [Mo2(μ-O2CCH3)2(CH 3CN)6](BF4)2 acts as the precursor compound. Crystallographic data for 4 are as follows: P21/c (No. 14), a = 19.683(3), b = 15.129(2), c = 21.084(1) A?, β = 101.30(1)°, V = 6848(2) A?3, Z = 4. There are two independent molecules of the cation in the unit cell, d(Mo-Mo) = 2.133(1) and 2.136(1) A?.
Mureinik
, p. 103 (1977)
Synthesis and crystal structure of [Re(CO)3(μ-CH3CO2)(THF)]4
Cotton, F. Albert,Dikarev, Evgeny V.,Petrukhina, Marina A.
, p. 304 - 309 (1999)
A tetrameric complex [Re(CO)3(μ-CH3CO2)(THF)]4 (1) is formed in high yield when the reaction product of Re(CO)5Cl with acetic acid in refluxing 1,2-dichlorobenzene is dissolved in THF. The use of Re2(CO)10 instead of rhenium pentacarbonyl chloride also affords 1. The characterization of 1·3THF·0.5C6H14 has been accomplished by X-ray crystallography. The structure of the tetrameric molecule 1 consists of four rhenium(I) atoms bridged by four acetate ligands. The coordination of each metal center is fulfilled by three CO groups and one THF molecule in a way that all carbonyls are trans to oxygen atoms. The geometry of each acetate bridge is anti-syn providing a Re to Re separation of 5.40 A. This bonding mode is seen here for the first time in rhenium carboxylates. Different coordination types for Re-RCO2 interaction are also discussed in the paper.