TY - JOUR

T1 - Trifluoromethyl-Substituted Benzocyclobutenone and Benzocyclobutenedione

T2 - The Structure Anomaly of (Benzocyclobutenedione)tricarbonylchromium Complexes

AU - Böning (née Pfennig), Monika

AU - Dongol, Krishna Gopal

AU - Romero Boston, Geanne Marize

AU - Schmitz, Stefan

AU - Wartchow, Rudolf

AU - Samaniego-Rojas, Juan D.

AU - Köster, Andreas M.

AU - Butenschön, Holger

N1 - Funding information: This research was kindly supported by the Gottlieb Daimler- and Karl Benz-Foundation (doctoral fellowship to K.G.D.) and by the Deutsche Forschungsgemeinschaft (BU 814/7-1, 7-2). We are indebted to Dr. Michael Wiebcke, Institut für Anorganische Chemie, Leibniz Universität Hannover, for help with a crystallographic analysis. J.D.S.-R. gratefully acknowledges a CONACyT Ph.D. fellowship (490270). The research at Cinvestav was supported by the SEP-Cinvestav project 65 and the CONACyT project GIC 268251.

PY - 2019/8/1

Y1 - 2019/8/1

N2 - The syntheses of methoxy- and trifluoromethyl-substituted benzocyclobutenone and benzocyclobutenedione tricarbonylchromium complexes are described. As with the unsubstituted complex, a route via the respective acetals was used. However, attempts to hydrolyze rac-tricarbonyl[1,2-bis(ethylenedioxy)-3-(trifluoromethyl)benzocyclobutene]chromium(0) (rac-12) resulted in only a single hydrolysis and led to rac-tricarbonyl{η6-[2-(ethylendioxy)-3-(trifluoromethyl)benzocyclobutenone]}chromium(0) (rac-14) with different regioselectivity in comparison to the respective reaction of the methoxy-substituted derivative. The synthesis of the desired rac-tricarbonyl[3-(trifluoromethyl)benzocyclobutenedione]chromium(0) (rac-13) was finally achieved by a route via an acyclic diacetal. Compounds were characterized spectroscopically and in a number of cases also by crystal structure analyses. The unusual bending of the annelated cyclobutenedione ring toward the tricarbonylchromium moiety was observed for rac-tricarbonyl-[η6-(methoxybenzocyclobutenedione)chromium(0) (rac-4) as well. To gain more insight into the unusually large bending of the annelated cyclobutenedione or cyclobutenone rings toward the tricarbonylchromium group in some of the studied compounds, we also performed density functional theory (DFT) calculations. In general, the gas-phase DFT optimized structure parameters show good agreement with the crystal structure data, indicating that the cyclobutenedione or cyclobutenone ring bending is a molecular rather than a crystal-packing effect. The DFT optimized structure data also show that annelated cyclobutenedione rings bend more strongly toward the tricarbonylchromium group than do their cyclobutenone analogues. Moreover, the staggered conformation of the tricarbonylchromium group favors larger bending angles. Topological analyses of the electron density of the studied (arene)tricarbonylchromium complexes suggest that the cyclobutenedione ring bending originates from the bending of πorbitals of the arene ring toward the tricarbonylchromium group.

AB - The syntheses of methoxy- and trifluoromethyl-substituted benzocyclobutenone and benzocyclobutenedione tricarbonylchromium complexes are described. As with the unsubstituted complex, a route via the respective acetals was used. However, attempts to hydrolyze rac-tricarbonyl[1,2-bis(ethylenedioxy)-3-(trifluoromethyl)benzocyclobutene]chromium(0) (rac-12) resulted in only a single hydrolysis and led to rac-tricarbonyl{η6-[2-(ethylendioxy)-3-(trifluoromethyl)benzocyclobutenone]}chromium(0) (rac-14) with different regioselectivity in comparison to the respective reaction of the methoxy-substituted derivative. The synthesis of the desired rac-tricarbonyl[3-(trifluoromethyl)benzocyclobutenedione]chromium(0) (rac-13) was finally achieved by a route via an acyclic diacetal. Compounds were characterized spectroscopically and in a number of cases also by crystal structure analyses. The unusual bending of the annelated cyclobutenedione ring toward the tricarbonylchromium moiety was observed for rac-tricarbonyl-[η6-(methoxybenzocyclobutenedione)chromium(0) (rac-4) as well. To gain more insight into the unusually large bending of the annelated cyclobutenedione or cyclobutenone rings toward the tricarbonylchromium group in some of the studied compounds, we also performed density functional theory (DFT) calculations. In general, the gas-phase DFT optimized structure parameters show good agreement with the crystal structure data, indicating that the cyclobutenedione or cyclobutenone ring bending is a molecular rather than a crystal-packing effect. The DFT optimized structure data also show that annelated cyclobutenedione rings bend more strongly toward the tricarbonylchromium group than do their cyclobutenone analogues. Moreover, the staggered conformation of the tricarbonylchromium group favors larger bending angles. Topological analyses of the electron density of the studied (arene)tricarbonylchromium complexes suggest that the cyclobutenedione ring bending originates from the bending of πorbitals of the arene ring toward the tricarbonylchromium group.

UR - http://www.scopus.com/inward/record.url?scp=85071313600&partnerID=8YFLogxK

U2 - 10.1021/acs.organomet.9b00370

DO - 10.1021/acs.organomet.9b00370

M3 - Article

AN - SCOPUS:85071313600

VL - 38

SP - 3039

EP - 3052

JO - Organometallics

JF - Organometallics

SN - 0276-7333

IS - 15

ER -