`IUPAC` name for complex `[Mn(pi-C_(6)H_(5))(CO)_(3)]`:

Options

A. Tricarbonyl `(eta^(5)`-cyclopentadiene)manganes(I)
B. Tricarbonyl `(eta^(5)`-cyclopentadiene)manganes(I)
C. Tricarbonyl `(eta^(5)`-cyclopentadiene)manganes(I)
D. `(eta^(5)`-cyclopentadiene)manganes(I)

Answer

To determine the IUPAC name for the complex \([Mn(\eta^5-C_5H_5)(CO)_3]\), we can follow these steps:

### Step 1: Identify the central metal and its oxidation state
- The central metal in the complex is manganese (Mn).
- The ligand \(\eta^5-C_5H_5\) (which is cyclopentadienyl) has a charge of -1, and the carbonyl (CO) ligands are neutral.
- Let \(x\) be the oxidation state of manganese. The equation for the charge balance is:
\[ x + (-1) + 3(0) = 0 \implies x - 1 = 0 \implies x = +1 \]
- Thus, the oxidation state of manganese is +1.

### Step 2: Identify the ligands
- The complex contains two types of ligands:
1. \(\eta^5-C_5H_5\) (cyclopentadienyl) - a bidentate ligand.
2. CO (carbonyl) - a neutral ligand.

### Step 3: Count the number of each ligand
- There is one \(\eta^5-C_5H_5\) ligand and three CO ligands.

### Step 4: Name the ligands in alphabetical order
- The ligands are named as follows:
- Carbonyl (CO) is named first because it starts with 'C'.
- Cyclopentadienyl (\(\eta^5-C_5H_5\)) is named next.

### Step 5: Combine the ligand names with their prefixes
- The prefix for one cyclopentadienyl is "cyclopentadienyl" and for three carbonyls, we use "tri" to indicate three.
- Therefore, the ligand names combined are "tricarbonyl" and "cyclopentadienyl".

### Step 6: Write the complete name of the complex
- The complete name of the complex is written as:
\[ \text{tricarbonyl} \, \text{cyclopentadienyl} \, \text{manganese} \, (I) \]
- The oxidation state of manganese is indicated in Roman numerals in parentheses.

### Final Answer
The IUPAC name for the complex \([Mn(\eta^5-C_5H_5)(CO)_3]\) is:
**tricarbonyl cyclopentadienyl manganese(I)**

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