Microwave assisted synthesis of molybdenum and tungsten tetracarbonyl complexes with a pyrazolylpyridine ligand. Crystal structure of cis-[Mo(CO)4{ethyl[3-(2-pyridyl)-1-pyrazolyl]acetate}

Ana C Coelho,Jacek Klinowski,Isabel S Gonçalves,Martyn Pillinger,Filipe A Almeida Paz

doi:10.3390/11120940

Ana C Coelho, Jacek Klinowski + Show 3 more

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https://doi.org/10.3390/11120940

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Abstract

We report the one-step syntheses in good yields of the complexes cis-[M(CO)4(pzpy)] {M = Mo, W; pzpy = ethyl[3-(2-pyridyl)-1-pyrazolyl]acetate} directly from the corresponding M(CO)6 starting materials by using microwave-assisted heating and reaction times of either 30 s (M = Mo) or 15 min (M = W). The structure of the molybdenum tetracarbonyl complex was determined by single crystal X-ray diffraction. The compound is monomeric and the molybdenum atom has a highly distorted octahedral geometry. The close packing of the individual cis-[Mo(CO)4(pzpy)] species is essentially driven by the need to fill the space effectively, closely mediated by weak C-H-O and pi-pi interactions.

Highlights

Transition metal carbonyl compounds continue to be investigated for applications in various fields, catalysis [1,2,3,4], non-linear optics [5,6,7] and medicine [8,9,10]
The two N-donor atoms and the two carbonyl groups which make up the equatorial pseudo-plane of the {MoC4N2} octahedron are not all located on the same geometrical plane
In the crystal structure of 1, adjacent cis[Mo(CO)4(pzpy)] complexes close pack with their substituent groups facing each other and interconnected via two weak C–H···O hydrogen bonding interactions: While the –CH2–C(O)O group interacts with the coordinated carbonyl from a neighbouring complex, the N(3)-adjacent C–H moiety of the pyrazole ring donates its hydrogen to form a contact with the acetate group from the same neighbouring Mo complex (Table 2), leading to a hydrogen bonding motif best described by the R22(13) graph set (Figure 2a) [50]

Summary

Introduction

Transition metal carbonyl compounds continue to be investigated for applications in various fields, catalysis [1,2,3,4], non-linear optics [5,6,7] and medicine [8,9,10]. To the best of our knowledge, no crystal structures have been reported for group 6 tetracarbonyl complexes containing the ethyl[3-(2-pyridyl)-1-pyrazolyl]acetate ligand.

Results

Conclusion