Synthesis, Structural Characterization, and Theoretical Studies of Silver(I) Complexes of Dihydrobis(2‐mercapto‐benzothiazolyl) Borate

Abstract

The complexes [Ag{κ 3 -S,SЈ,H-H 2 B(mbz) 2 }(PR 3 )] x , (1: x = 2, R = Ph; 2: x = 1, R = Cy) (mbz = 2-mercaptobenzothiazolyl) and amidine based dihydro(2-mercaptobenzo-thiazolyl) borates, [HN=C(Ph)-NH(R)-H 2 B(mbz)] (3: R = 2,6-diisopropylphenyl and 4: R = Ph) were synthesized and characterized by various spectroscopic methods and single-crystal X-ray crystallography. Complex [Ag{κ 3 -S,SЈ,H-H 2 B(mbz) 2 }(PPh 3 )] 2 (1) has a dimeric structure in its crystalline state, in which central silver(I) atoms adopt a * Prof. Dr. S. Ghosh E-Mail: sghosh@iitm.ac.in [a] 588 distorted trigonal bipyramid arrangement. In contrast, complex [Ag{κ 3 -S,SЈ,H-H 2 B(mbz) 2 }(PCy 3 )] (2) has a monomeric structure in its crystalline state, in which the central silver(I) atoms adopt a distorted trigonal planar arrangement. Infrared spectroscopy was utilized as a tool for investigating the presence of M···H-B interactions. In addition, density functional theory (DFT) calculations were used to analyse the B-H···[M] bonding interaction in the metal borate complexes. Crystal Data for 1: C 64 H 50 B 2 Ag 2 S 8 N 4 P 2 , M r = 1430.86, triclinic, P1, a = 11.5839(8) Å, b = 11.6836(8) Å, c = 12.2097(9) Å, α = 76.233(6)°, β = 80.921(6)°, γ = 73.582(6)°, V = 1532.3(2) Å 3 , Z = 1, ρ calcd. = 1.551 mg·m -3 , μ = 1.009 mm -1 , F(000) = 724, R 1 = 0.0507, wR 2 = 0.0653, 7252 independent reflections [2θ Յ 58.48°] and 378 parameters, Goodness-of-fit on F 2 = 1.029. Crystal Data for 2: C 32 H 43 BAgS 4 N 2 P, M r = 733.57, monoclinic, P2 1 /n, a = 9.7847(3) Å, b = 25.6692(6) Å, c = 13.9303(4) Å, α = 90°, β = 99.334(3)°, γ = 90°, V = 3452.48(17) Å 3 , Z = 4, ρ calcd. = 1.411 mg·m -3 , μ = 0.897 mm -1 , F(000) = 1520, R 1 = 0.0574, wR 2 = 0.0979, 8391 independent reflections [2θ Յ 58.066°] and 378 parameters, Goodness-of-fit on F 2 = 1.034. Crystal Data for 3: C 26 H 30 BS 2 N 3 , M r = 457.44, monoclinic, P2 1 /n, a = 12.8305(5) Å, b = 14.3085(4) Å, c = 13.9844(4) Å, α = 90°, β = 98.940(3)°, γ = 90°, V = 2536.14(14) Å 3 , Z = 4, ρ calcd. = 1.198 mg·m -3 , μ = 0.228 mm -1 , F(000) = 968, R 1 = 0.1074, wR 2 = 0.1880, 8484 independent reflections [2θ Յ 64.764°] and 310 parameters, Goodness-of-fit on F 2 = 1.106. Crystal Data for 4: C 20 H 18 BS 2 N 3 , M r = 585.61, monoclinic, P2 1 /c, a = 9.9343(10) Å, b = 14.2927(17) Å, c = 23.194(3) Å, α = 90°, β = 92.483(4)°, γ = 90°, V = 3290.2(6) Å 3 , Z = 4, ρ calcd. = 1.182 mg·m -3 , μ = 0.192 mm -593 independent reflections [2θ Յ 50.998°] and 447 parameters, Goodness-of-fit on F 2 = 1.032.Supporting Information (see footnote on the first page of this article): Detailed information about the packing diagram of compounds 3 and 4, spectroscopic data and DFT-computed results for compounds 1, 2, 3 and 4 have been provided in the supporting information.

Adding to the Family of Copper Complexes Featuring Borohydride Ligands Based on 2-Mercaptopyridyl Units

“…The ligand was based on soft sulfur donor atoms [16], and perhaps more significantly, greater flexibility had been incorporated into the ligand by addition of the extra atom between the boron and the donor atom. It was this greater flexibility within the ligand structure that opened up the potential for activation at the boron bridgehead and formation of metal-borane (metallaboratrane) complexes [17][18][19][20][24][25][26][27], giving rise to reactivity not observed in the analogous polypyrazolylborate ligands [10][11][12][13][14][15][16]. Over the following twenty years since the first report of hydride migration from the boron center of a scorpionate ligand, a number of research groups have focused on new, more flexible borohydride ligands containing a range of supporting units based on nitrogen [28][29][30][31] and other sulfur heterocycles [32][33][34][35][36][37][38][39][40][41][42][43][44][45][46].…”

“…The ligand was based on soft sulfur donor atoms [16], and perhaps more significantly, greater flexibility had been incorporated into the ligand by addition of the extra atom between the boron and the donor atom. It was this greater flexibility within the ligand structure that opened up the potential for activation at the boron bridgehead and formation of metal-borane (metallaboratrane) complexes [17][18][19][20][24][25][26][27], giving rise to reactivity not observed in the analogous polypyrazolylborate ligands [10][11][12][13][14][15][16].Inorganics 2019, 7, x FOR PEER REVIEW 2 of 11 differences when compared to Trofimenko's original scorpionates. The ligand was based on soft sulfur donor atoms [16], and perhaps more significantly, greater flexibility had been incorporated into the ligand by addition of the extra atom between the boron and the donor atom.…”

Copper(I) Complex of Dihydro Bis(2‐Mercapto Benzimidazolyl) Borate as an Efficient Homogeneous Catalyst for the Synthesis of 2H‐Indazoles and 5‐Substituted 1H‐Tetrazoles

“…[74][75][76][77] Although this sulfur donor ligand, has a rich history as a soft, strongly ligating system for late-transition metals, literaturea survey reveals that Cu(I) complexes of Sdonor scorpionate ligands are less explored. Considering these outstanding features, [78][79][80] transition metal-scorpionate complexes have often been the homogeneous catalytic of choice and various applications such as CÀ H activations, aerobic oxidations, polymerizations, enzyme mimicry, and multicomponent reactions have been reported. [81][82][83][84][85] In this article and as part of our ongoing studies on the catalytic applications of copper complexes in the organic transformations, [86][87][88][89] we examined the effect of Cu(I) complexes with bipodal sulfur donor borate ligands based on 2mercaptobenzimidazole and different phosphine co-ligands as an effective homogeneous catalytic system for the formation of 2H-indazoles and 5-substituted 1H-tetrazoles.…”

“…Although this sulfur donor ligand, has a rich history as a soft, strongly ligating system for late‐transition metals, literaturea survey reveals that Cu(I) complexes of S‐donor scorpionate ligands are less explored. Considering these outstanding features, [78–80] transition metal‐scorpionate complexes have often been the homogeneous catalytic of choice and various applications such as C−H activations, aerobic oxidations, polymerizations, enzyme mimicry, and multicomponent reactions have been reported [81–85] …”

Five‐Membered Ruthenacycles: Ligand‐Assisted Alkyne Insertion into 1,3‐N,S‐Chelated Ruthenium Borate Species

“…[13] The activation of terminal alkynes by ruthenium and iridium complexes has also been established throughl igandassisted protons huttle (LAPS) mechanism; [10c, [13][14][15] the LAPS mechanism for some alkyne-vinylidene tautomerizations has been proposed in Scheme 1. [10c] Although av ariety of transition metal boron complexes are knowni nt he literature, [16][17][18] their chemistryw ith small organic molecules has not been explored so far. [19][20][21][22] As ap art of our ongoing research, we have explored the reactivity of various transition metal boron complexes with alkynes.…”