Synthesis, Characterization, and Electronic Structure of New Type of Heterometallic Boride Clusters

Abstract

The reaction of [Cp*TaCl(4)], 1 (Cp* = η(5)-C(5)Me(5)), with [LiBH(4)·THF] at -78 °C, followed by thermolysis in the presence of excess [BH(3)·THF], results in the formation of the oxatantalaborane cluster [(Cp*Ta)(2)B(4)H(10)O], 2 in moderate yield. Compound 2 is a notable example of an oxatantalaborane cluster where oxygen is contiguously bound to both the metal and boron. Upon availability of 2, a room temperature reaction was performed with [Fe(2)(CO)(9)], which led to the isolation of [(Cp*Ta)(2)B(2)H(4)O{H(2)Fe(2)(CO)(6)BH}], 3. Compound 3 is an unusual heterometallic boride cluster in which the [Ta(2)Fe(2)] atoms define a butterfly framework with one boron atom lying in a semi-interstitial position. Likewise, the diselenamolybdaborane, [(Cp*Mo)(2)B(4)H(4)Se(2)], 4 was treated with an excess of [Fe(2)(CO)(9)] to afford the heterometallic boride cluster [(Cp*MoSe)(2)Fe(6)(CO)(13)B(2)(BH)(2)], 5. The cluster core of 5 consists of a cubane [Mo(2)Se(2)Fe(2)B(2)] and a tricapped trigonal prism [Fe(6)B(3)] fused together with four atoms held in common between the two subclusters. In the tricapped trigonal prism subunit, one of the boron atoms is completely encapsulated and bonded to six iron and two boron atoms. Compounds 2, 3, and 5 have been characterized by mass spectrometry, IR, (1)H, (11)B, (13)C NMR spectroscopy, and the geometric structures were unequivocally established by crystallographic analysis. The density functional theory calculations yielded geometries that are in close agreement with the observed structures. Furthermore, the calculated (11)B NMR chemical shifts also support the structural characterization of the compounds. Natural bond order analysis and Wiberg bond indices are used to gain insight into the bonding patterns of the observed geometries of 2, 3, and 5.

Synthesis and Structural Characterization of New Divanada‐ and Diniobaboranes Containing Chalcogen Atoms

“…Compound 3 is isostructural with oxatantalaborane, [(Cp*Ta) 2 B 4 H 10 O] 24. The number of metal, boron, and hydrogen atoms in compound 3 and in oxatantalaborane remain the same and, considering the close similarity of the chemical shifts, indicates that the structures are closely related.…”

Chemistry of ruthenium σ-borane complex, [Cp∗RuCO(μ-H)BH2L] (Cp∗= η5-C5Me5; L = C7H4NS2) with terminal and internal alkynes: Structural characterization of vinyl hydroborate and vinyl complexes of ruthenium

“…Transition-metal complexes of boron, [1][2][3] have attracted considerable interest over the last few decades. A wide variety of coordination modes of these complexes have been structurally characterized and theoretically examined [4] that led to the progress of new subclasses such as sigma, agostic, boryl, borylene, boratrane and more [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Hill, Parkin, Bourissou, Sabo-Etienne, Braunschweig, Weller, Aldridge, and others have synthesized a number of such novel complexes by substitution and addition reactions of boron containing ligands at an electronically unsaturated metal centre [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34].…”

Synthesis and characterization of novel eleven-vertex dimetallaheteroborane clusters containing Heavier group 16 elements

“…Similarly, the first boron-capped-pentagonal bipyramidal metallacarborane [(Ph 3 P) 2 HRuCB 6 H 4 (OMe) 3 ], B was isolated from the reaction of [nido-B 10 H 12 CH] À Cs þ with [RuCl 2 (PPh 3 ) 3 ] [34]. More recently, we have reported the first example of bicapped pentagonal bipyramidal metallaborane [(Cp*Ta) 2 B 5 H 7 {Fe(CO) 3 } 2 ], C with a deformed equatorial plane [35]. Over two decades ago, Mingos proposed that a putative 10-vertex cluster Ni 10 (CO) 18 , D and a 11-vertex cluster Ni 11 (CO) 19 , E could have a tricapped and tetracapped pentagonal bipyramidal geometry respectively [36].…”