Saha Koushik, Ramalakshmi Rongala, Gomosta Suman, Pathak Kriti, Dorcet Vincent, Roisnel Thierry, Halet Jean-François, Ghosh Sundargopal
Department of Chemistry, Indian Institute of Technology Madras, Chennai, 600036, India.
Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS, Ecole Nationale Supérieure de Chimie de Rennes-Université de Rennes 1, 35042, Rennes Cedex, France.
Chemistry. 2017 Jul 21;23(41):9812-9820. doi: 10.1002/chem.201701423. Epub 2017 Jun 9.
A series of new bis(σ)borate and agostic complexes of group 7 metals have been synthesized and structurally characterized from various borate ligands, such as trihydrobis(benzothiazol-2-yl)amideborate (Na[(H B)bbza]), trihydro(2-aminobenzothiazolyl)borate (Na[(H B)abz]), and dihydrobis(2-mercaptopyridyl)borate (Na[(H B)mp ]) (bbza=bis(benzothiazol-2-yl)amine, abz=2-aminobenzothiazolyl, and mp=2-mercaptopyridyl). Photolysis of [Mn (CO) ] with Na[(H B)bbza] formed bis(σ)borate complex [Mn(CO) (μ-H) BHNCSC H (NR)] (1; R=NCSC H ). Octahedral complex [Re(CO) (N C S C H ) ] (2) was generated under similar reaction conditions with [Re (CO) ]. Similarly, when [Mn (CO) ] was treated with Na[(H B)abz], bis(σ)borate complex [Mn(CO) (μ-H) BH(HN CSC H )] (3) and the agostic complex [Mn(CO) (μ-H)BH(HN CSC H ) ] (4) were formed. To probe the potential formation of agostic complexes of the heavier group 7 metals, we carried out the photolysis of [M (CO) ] with Na[(H B)mp ] and found that [M(CO) (μ-H)BH(C H NS) ] (5: M=Re; 6: M=Mn) was formed in moderate yield. Complexes 1 and 3 feature a (κ -H,H,N) coordination mode, whereas 4, 5, and 6 display both (κ -H,N,N) and (κ -H,S,S) modes of the corresponding ligands. To investigate the lability of the CO ligands of 1 and 3, we treated the complexes with phosphine ligands that generated novel bis(σ)borate complexes [Mn(μ-H) (BHNCSC H )(NR)(CO) PL L'] (R=NCSC H ; 7 a: L=L'=Ph; 7 b: L=Ph, L'=Me) and [Mn(μ-H) BHN(NCSC H )R(CO) PL L'] (R=NCSC H ; 8 a: L=L'=Ph; 8 b: L=Ph, L'=Me). Complexes 7 and 8 are structural isomers with different coordination modes of the bbza ligand. In addition, DFT calculations were performed to shed some light on the bonding and electronic structures of these complexes.
一系列新的第7族金属双（σ）硼酸盐和螯合配合物已通过各种硼酸盐配体合成并进行了结构表征，这些配体包括三氢双（苯并噻唑-2-基）酰胺硼酸盐（Na[(H B)bbza]）、三氢（2-氨基苯并噻唑基）硼酸盐（Na[(H B)abz]）和二氢双（2-巯基吡啶基）硼酸盐（Na[(H B)mp ]）（bbza = 双（苯并噻唑-2-基）胺，abz = 2-氨基苯并噻唑基，mp = 2-巯基吡啶基）。用Na[(H B)bbza]对[Mn (CO) ]进行光解，形成双（σ）硼酸盐配合物[Mn(CO) (μ-H) BHNCSC H (NR)]（1；R = NCSC H ）。在类似的反应条件下，用[Re (CO) ]生成了八面体配合物[Re(CO) (N C S C H ) ]（2）。同样，当用Na[(H B)abz]处理[Mn (CO) ]时，则形成双（σ）硼酸盐配合物[Mn(CO) (μ-H) BH(HN CSC H )]（3）和螯合配合物[Mn(CO) (μ-H)BH(HN CSC H ) ]（4）。为了探究较重的第7族金属形成螯合配合物的可能性，我们用Na[(H B)mp ]对[M (CO) ]进行了光解，发现以中等产率形成了[M(CO) (μ-H)BH(C H NS) ]（5：M = Re；6：M = Mn）。配合物1和3具有（κ -H,H,N）配位模式，而4、5和6则显示出相应配体的（κ -H,N,N）和（κ -H,S,S）模式。为了研究1和3中CO配体的不稳定性，我们用膦配体处理这些配合物，生成了新型双（σ）硼酸盐配合物[Mn(μ-H) (BHNCSC H )(NR)(CO) PL L']（R = NCSC H ；7 a：L = L' = Ph；7 b：L = Ph，L' = Me）和[Mn(μ-H) BHN(NCSC H )R(CO) PL L']（R = NCSC H ；8 a：L = L' = Ph；8 b：L = Ph，L' = Me）。配合物7和8是bbza配体具有不同配位模式的结构异构体。此外，还进行了密度泛函理论（DFT）计算，以阐明这些配合物的键合和电子结构。
