Novel Metal‐Organic Frameworks Incorporating [Cp°₂Mo₂P₄S] (Cp° = 1‐tBu‐3,4‐Me₂C₅H₂), P₄S₃ and Cu₂I₂ Building Blocks

Abstract

The synthesis and characterization of [Cp°2Mo2P4S] (1) and [Cp°2Mo2P2S3] (2) (Cp° = 1‐tBu‐3,4‐Me2C5H2) has been described. The reaction of 1 in CH2Cl2 with 2 equiv. of CuI in MeCN under diffusion conditions gave [(Cp°2Mo2P4S)3(CuI)4]n (6a). The crystal structure of 6a consists of helical substructures of opposed chirality which are formed by the coordination of two Cu2I2 rings to three phosphorus atoms of the cyclo‐P4S middle deck of 1. The resulting helix is connected with four helices of the same chirality by front‐backside P coordination of another 1 unit. Compound 6a can reversibly include or release CH2Cl2 molecules without loosing its crystalline character. Thus, storing crystals of 6a under CH2Cl2 results in the formation of 6a·0.55CH2Cl2 (6b), the unit cell volume increasing by 113.6 Å3 per formula unit, while in high vacuum the unit cell volume of 6b decreases to the value of 6a. The reaction of 1 with CuI in the presence of P4S3 gave a mixture of two isomeric polymers 7 and 8 of composition [(Cp°2Mo2P4S)(P4S3)(CuI)2]n. The crystal structures of both compounds 7 and 8 contain linear strands of [1(CuI)2]n and [(P4S3)(CuI)2]n with planar Cu2I2 rings as common interface. A two‐dimensional framework is formed by interpenetration of both types of strands. The analogous reaction of the mixture of [Cp*2Mo2P4S] (Cp* = C5Me5) and P4S3 with CuI gave [(Cp*2Mo2P4S)(P4S3)(CuI)2]n (9). Contrary to the structures of 7 and 8 in this compound coordination of adjacent P atoms of the η3‐P3 ligand and the η2‐PS dumbbell leads to the formation of one‐dimensional ribbons.

Electronic Structure and Donor Ability of an Unsaturated Triphosphorus-Bridged Dimolybdenum Complex

“…Besides this, we should remark that the chemical shift for the central P atom in 2 is far lower (by some 250 ppm) than the ones previously determined for the few η 3 :η 3 -bridged complexes reported to date (ca. −375 ppm in [Mo 2 Cp′ 2 (μ-η 3 :η 3 -P 3 )(μ 2 -PS)] 5 , 6 and ca. −380 ppm in [Fe 2 (C 5 H 2 t Bu 3 ) 2 (μ-η 3 :η 3 -P 3 )] n ( n = 0, −1)).…”

“…4 There are two main points of interest concerning this compound: in the first place, we note that 2 is a rare example of a complex bearing a noncyclic P 3 ligand bridging a dimetal center in a symmetrical η 3 :η 3 mode. The only previously reported complexes of this type are the phosphorus sulfide complexes [Mo 2 Cp′ 2 (μ-η 3 :η 3 -P 3 )(μ 2 -PS)] (Cp′ = C 5 Me 5 , 5 C 5 H 2 t Bu 3 ), 6 the diiron radical [Fe 2 (C 5 H 2 t Bu 3 ) 2 (μ-η 3 :η 3 -P 3 )], a product obtained in 2% yield from the reaction of [Fe 2 (C 5 H 2 t Bu 3 ) 2 (CO) 4 (μ-κ 1 :κ 1 -P 4 )] with P≡C t Bu in refluxing toluene, 7 and its anionic derivative [Fe 2 (C 5 H 2 t Bu 3 ) 2 (μ-η 3 :η 3 -P 3 )] − , a complex recently prepared by degrading the above P 4 -bridged complex with a NHC ligand and thought to contain no metal–metal bond. 8 As a result of all of the above, only very limited chemistry of the acyclic P 3 ligand in such a coordination mode has been explored to date, it being restricted to some reactions of the mentioned dimolybdenum complexes with [Cr(CO) 5 (THF)] 5 and with different M(I)-based electrophiles (M = Cu, Ag).…”

“… 8 As a result of all of the above, only very limited chemistry of the acyclic P 3 ligand in such a coordination mode has been explored to date, it being restricted to some reactions of the mentioned dimolybdenum complexes with [Cr(CO) 5 (THF)] 5 and with different M(I)-based electrophiles (M = Cu, Ag). 6 , 9 On the other hand, a description of the chemical bonding in 2 was not obvious itself because application of the 18-electron rule to this molecule, if considering the P t Bu 2 and P 3 ligands as three- and five-electron donors, respectively (neutral counting scheme), would lead to the formulation of a Mo–Mo triple bond for this molecule ( A in Chart 1 ). However, this was rather inconsistent with the actual intermetallic separation of 2.6221(3) Å in 2 , significantly longer than expected for a 30-electron complex with P-bridging ligands (cf.…”